Update libz to zlib 1.2.11 and reapply local patches as far as this

made sense.

Tested in snaps for a few days. deraadt helped with fitting things on
floppies and jmatthew found a bug I introduced.

ok deraadt

21 files changed, 3402 insertions, 1896 deletions

diff --git a/sys/lib/libz/Makefile b/sys/lib/libz/Makefile
index 93f04fefd5c..f24d2193c04 100644
--- a/sys/lib/libz/Makefile
+++ b/sys/lib/libz/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.8 2003/12/18 02:27:13 millert Exp $
+#	$OpenBSD: Makefile,v 1.9 2021/07/04 14:24:49 tb Exp $
 #	$NetBSD: Makefile,v 1.2 1997/01/22 01:36:30 cgd Exp $
 
 LIB=	z
@@ -7,6 +7,7 @@ NOPROFILE=
 
 # Tweak knobs to generate small libz code
 CPPFLAGS+=	-DSLOW -DSMALL -DNOBYFOUR -DNO_GZIP -DDYNAMIC_CRC_TABLE
+CPPFLAGS+=	-DBUILDFIXED
 CPPFLAGS+=	-I. ${ZCPPFLAGS}
 
 # files to be copied down from libz.
diff --git a/sys/lib/libz/adler32.c b/sys/lib/libz/adler32.c
index 6afbdc620a4..ca34e389ed3 100644
--- a/sys/lib/libz/adler32.c
+++ b/sys/lib/libz/adler32.c
@@ -1,13 +1,14 @@
-/*	$OpenBSD: adler32.c,v 1.10 2011/07/07 02:57:24 deraadt Exp $	*/
+/*	$OpenBSD: adler32.c,v 1.11 2021/07/04 14:24:49 tb Exp $ */
 /* adler32.c -- compute the Adler-32 checksum of a data stream
- * Copyright (C) 1995-2004 Mark Adler
+ * Copyright (C) 1995-2011, 2016 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
-#define ZLIB_INTERNAL
-#include "zlib.h"
+#include "zutil.h"
 
-#define BASE 65521UL    /* largest prime smaller than 65536 */
+local uLong adler32_combine_ OF((uLong adler1, uLong adler2, z_off64_t len2));
+
+#define BASE 65521U     /* largest prime smaller than 65536 */
 #define NMAX 5552
 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
 
@@ -17,46 +18,51 @@
 #define DO8(buf,i)  DO4(buf,i); DO4(buf,i+4);
 #define DO16(buf)   DO8(buf,0); DO8(buf,8);
 
-/* use NO_DIVIDE if your processor does not do division in hardware */
+/* use NO_DIVIDE if your processor does not do division in hardware --
+   try it both ways to see which is faster */
 #ifdef NO_DIVIDE
-#  define MOD(a) \
+/* note that this assumes BASE is 65521, where 65536 % 65521 == 15
+   (thank you to John Reiser for pointing this out) */
+#  define CHOP(a) \
+    do { \
+        unsigned long tmp = a >> 16; \
+        a &= 0xffffUL; \
+        a += (tmp << 4) - tmp; \
+    } while (0)
+#  define MOD28(a) \
     do { \
-        if (a >= (BASE << 16)) a -= (BASE << 16); \
-        if (a >= (BASE << 15)) a -= (BASE << 15); \
-        if (a >= (BASE << 14)) a -= (BASE << 14); \
-        if (a >= (BASE << 13)) a -= (BASE << 13); \
-        if (a >= (BASE << 12)) a -= (BASE << 12); \
-        if (a >= (BASE << 11)) a -= (BASE << 11); \
-        if (a >= (BASE << 10)) a -= (BASE << 10); \
-        if (a >= (BASE << 9)) a -= (BASE << 9); \
-        if (a >= (BASE << 8)) a -= (BASE << 8); \
-        if (a >= (BASE << 7)) a -= (BASE << 7); \
-        if (a >= (BASE << 6)) a -= (BASE << 6); \
-        if (a >= (BASE << 5)) a -= (BASE << 5); \
-        if (a >= (BASE << 4)) a -= (BASE << 4); \
-        if (a >= (BASE << 3)) a -= (BASE << 3); \
-        if (a >= (BASE << 2)) a -= (BASE << 2); \
-        if (a >= (BASE << 1)) a -= (BASE << 1); \
+        CHOP(a); \
         if (a >= BASE) a -= BASE; \
     } while (0)
-#  define MOD4(a) \
+#  define MOD(a) \
     do { \
-        if (a >= (BASE << 4)) a -= (BASE << 4); \
-        if (a >= (BASE << 3)) a -= (BASE << 3); \
-        if (a >= (BASE << 2)) a -= (BASE << 2); \
-        if (a >= (BASE << 1)) a -= (BASE << 1); \
+        CHOP(a); \
+        MOD28(a); \
+    } while (0)
+#  define MOD63(a) \
+    do { /* this assumes a is not negative */ \
+        z_off64_t tmp = a >> 32; \
+        a &= 0xffffffffL; \
+        a += (tmp << 8) - (tmp << 5) + tmp; \
+        tmp = a >> 16; \
+        a &= 0xffffL; \
+        a += (tmp << 4) - tmp; \
+        tmp = a >> 16; \
+        a &= 0xffffL; \
+        a += (tmp << 4) - tmp; \
         if (a >= BASE) a -= BASE; \
     } while (0)
 #else
 #  define MOD(a) a %= BASE
-#  define MOD4(a) a %= BASE
+#  define MOD28(a) a %= BASE
+#  define MOD63(a) a %= BASE
 #endif
 
 /* ========================================================================= */
-uLong ZEXPORT adler32(adler, buf, len)
+uLong ZEXPORT adler32_z(adler, buf, len)
     uLong adler;
     const Bytef *buf;
-    uInt len;
+    z_size_t len;
 {
     unsigned long sum2;
     unsigned n;
@@ -88,7 +94,7 @@ uLong ZEXPORT adler32(adler, buf, len)
         }
         if (adler >= BASE)
             adler -= BASE;
-        MOD4(sum2);             /* only added so many BASE's */
+        MOD28(sum2);            /* only added so many BASE's */
         return adler | (sum2 << 16);
     }
 
@@ -124,25 +130,56 @@ uLong ZEXPORT adler32(adler, buf, len)
 }
 
 /* ========================================================================= */
-uLong ZEXPORT adler32_combine(adler1, adler2, len2)
+uLong ZEXPORT adler32(adler, buf, len)
+    uLong adler;
+    const Bytef *buf;
+    uInt len;
+{
+    return adler32_z(adler, buf, len);
+}
+
+/* ========================================================================= */
+local uLong adler32_combine_(adler1, adler2, len2)
     uLong adler1;
     uLong adler2;
-    z_off_t len2;
+    z_off64_t len2;
 {
     unsigned long sum1;
     unsigned long sum2;
     unsigned rem;
 
+    /* for negative len, return invalid adler32 as a clue for debugging */
+    if (len2 < 0)
+        return 0xffffffffUL;
+
     /* the derivation of this formula is left as an exercise for the reader */
-    rem = (unsigned)(len2 % BASE);
+    MOD63(len2);                /* assumes len2 >= 0 */
+    rem = (unsigned)len2;
     sum1 = adler1 & 0xffff;
     sum2 = rem * sum1;
     MOD(sum2);
     sum1 += (adler2 & 0xffff) + BASE - 1;
     sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem;
-    if (sum1 > BASE) sum1 -= BASE;
-    if (sum1 > BASE) sum1 -= BASE;
-    if (sum2 > (BASE << 1)) sum2 -= (BASE << 1);
-    if (sum2 > BASE) sum2 -= BASE;
+    if (sum1 >= BASE) sum1 -= BASE;
+    if (sum1 >= BASE) sum1 -= BASE;
+    if (sum2 >= ((unsigned long)BASE << 1)) sum2 -= ((unsigned long)BASE << 1);
+    if (sum2 >= BASE) sum2 -= BASE;
     return sum1 | (sum2 << 16);
 }
+
+/* ========================================================================= */
+uLong ZEXPORT adler32_combine(adler1, adler2, len2)
+    uLong adler1;
+    uLong adler2;
+    z_off_t len2;
+{
+    return adler32_combine_(adler1, adler2, len2);
+}
+
+uLong ZEXPORT adler32_combine64(adler1, adler2, len2)
+    uLong adler1;
+    uLong adler2;
+    z_off64_t len2;
+{
+    return adler32_combine_(adler1, adler2, len2);
+}
diff --git a/sys/lib/libz/compress.c b/sys/lib/libz/compress.c
index 70ab34d7d5b..a76385c07f0 100644
--- a/sys/lib/libz/compress.c
+++ b/sys/lib/libz/compress.c
@@ -1,10 +1,9 @@
-/*	$OpenBSD: compress.c,v 1.1 2011/07/07 02:57:24 deraadt Exp $	*/
+/*	$OpenBSD: compress.c,v 1.2 2021/07/04 14:24:49 tb Exp $ */
 /* compress.c -- compress a memory buffer
- * Copyright (C) 1995-2003 Jean-loup Gailly.
+ * Copyright (C) 1995-2005, 2014, 2016 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
-
 #define ZLIB_INTERNAL
 #include "zlib.h"
 
@@ -28,16 +27,11 @@ int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
 {
     z_stream stream;
     int err;
+    const uInt max = (uInt)-1;
+    uLong left;
 
-    stream.next_in = (Bytef*)source;
-    stream.avail_in = (uInt)sourceLen;
-#ifdef MAXSEG_64K
-    /* Check for source > 64K on 16-bit machine: */
-    if ((uLong)stream.avail_in != sourceLen) return Z_BUF_ERROR;
-#endif
-    stream.next_out = dest;
-    stream.avail_out = (uInt)*destLen;
-    if ((uLong)stream.avail_out != *destLen) return Z_BUF_ERROR;
+    left = *destLen;
+    *destLen = 0;
 
     stream.zalloc = (alloc_func)0;
     stream.zfree = (free_func)0;
@@ -46,15 +40,26 @@ int ZEXPORT compress2 (dest, destLen, source, sourceLen, level)
     err = deflateInit(&stream, level);
     if (err != Z_OK) return err;
 
-    err = deflate(&stream, Z_FINISH);
-    if (err != Z_STREAM_END) {
-        deflateEnd(&stream);
-        return err == Z_OK ? Z_BUF_ERROR : err;
-    }
-    *destLen = stream.total_out;
+    stream.next_out = dest;
+    stream.avail_out = 0;
+    stream.next_in = (z_const Bytef *)source;
+    stream.avail_in = 0;
+
+    do {
+        if (stream.avail_out == 0) {
+            stream.avail_out = left > (uLong)max ? max : (uInt)left;
+            left -= stream.avail_out;
+        }
+        if (stream.avail_in == 0) {
+            stream.avail_in = sourceLen > (uLong)max ? max : (uInt)sourceLen;
+            sourceLen -= stream.avail_in;
+        }
+        err = deflate(&stream, sourceLen ? Z_NO_FLUSH : Z_FINISH);
+    } while (err == Z_OK);
 
-    err = deflateEnd(&stream);
-    return err;
+    *destLen = stream.total_out;
+    deflateEnd(&stream);
+    return err == Z_STREAM_END ? Z_OK : err;
 }
 
 /* ===========================================================================
@@ -75,5 +80,6 @@ int ZEXPORT compress (dest, destLen, source, sourceLen)
 uLong ZEXPORT compressBound (sourceLen)
     uLong sourceLen;
 {
-    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + 11;
+    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
+           (sourceLen >> 25) + 13;
 }
diff --git a/sys/lib/libz/crc32.c b/sys/lib/libz/crc32.c
index eac7d74e563..8fb352c421c 100644
--- a/sys/lib/libz/crc32.c
+++ b/sys/lib/libz/crc32.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: crc32.c,v 1.12 2011/07/07 02:57:24 deraadt Exp $	*/
+/*	$OpenBSD: crc32.c,v 1.13 2021/07/04 14:24:49 tb Exp $ */
 /* crc32.c -- compute the CRC-32 of a data stream
- * Copyright (C) 1995-2005 Mark Adler
+ * Copyright (C) 1995-2006, 2010, 2011, 2012, 2016 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  *
  * Thanks to Rodney Brown <rbrown64@csc.com.au> for his contribution of faster
@@ -16,6 +16,8 @@
   of the crc tables.  Therefore, if you #define DYNAMIC_CRC_TABLE, you should
   first call get_crc_table() to initialize the tables before allowing more than
   one thread to use crc32().
+
+  DYNAMIC_CRC_TABLE and MAKECRCH can be #defined to write out crc32.h.
  */
 
 #ifdef MAKECRCH
@@ -24,42 +26,18 @@
 #    define DYNAMIC_CRC_TABLE
 #  endif /* !DYNAMIC_CRC_TABLE */
 #endif /* MAKECRCH */
-  
-#include "zutil.h"      /* for STDC and FAR definitions */
 
-#define local static
-
-#ifndef _KERNEL
-/* Find a four-byte integer type for crc32_little() and crc32_big(). */
-#ifndef NOBYFOUR
-#  ifdef STDC           /* need ANSI C limits.h to determine sizes */
-#    include <limits.h>
-#    define BYFOUR
-#    if (UINT_MAX == 0xffffffffUL)
-       typedef unsigned int u4;
-#    else
-#      if (ULONG_MAX == 0xffffffffUL)
-         typedef unsigned long u4;
-#      else
-#        if (USHRT_MAX == 0xffffffffUL)
-           typedef unsigned short u4;
-#        else
-#          undef BYFOUR     /* can't find a four-byte integer type! */
-#        endif
-#      endif
-#    endif
-#  endif /* STDC */
-#endif /* !NOBYFOUR */
-#endif
+#include "zutil.h"      /* for STDC and FAR definitions */
 
 /* Definitions for doing the crc four data bytes at a time. */
+#if !defined(NOBYFOUR) && defined(Z_U4)
+#  define BYFOUR
+#endif
 #ifdef BYFOUR
-#  define REV(w) (((w)>>24)+(((w)>>8)&0xff00)+ \
-                (((w)&0xff00)<<8)+(((w)&0xff)<<24))
    local unsigned long crc32_little OF((unsigned long,
-                        const unsigned char FAR *, unsigned));
+                        const unsigned char FAR *, z_size_t));
    local unsigned long crc32_big OF((unsigned long,
-                        const unsigned char FAR *, unsigned));
+                        const unsigned char FAR *, z_size_t));
 #  define TBLS 8
 #else
 #  define TBLS 1
@@ -69,14 +47,16 @@
 local unsigned long gf2_matrix_times OF((unsigned long *mat,
                                          unsigned long vec));
 local void gf2_matrix_square OF((unsigned long *square, unsigned long *mat));
+local uLong crc32_combine_ OF((uLong crc1, uLong crc2, z_off64_t len2));
+
 
 #ifdef DYNAMIC_CRC_TABLE
 
 local volatile int crc_table_empty = 1;
-local unsigned long FAR crc_table[TBLS][256];
+local z_crc_t FAR crc_table[TBLS][256];
 local void make_crc_table OF((void));
 #ifdef MAKECRCH
-   local void write_table OF((FILE *, const unsigned long FAR *));
+   local void write_table OF((FILE *, const z_crc_t FAR *));
 #endif /* MAKECRCH */
 /*
   Generate tables for a byte-wise 32-bit CRC calculation on the polynomial:
@@ -106,9 +86,9 @@ local void make_crc_table OF((void));
 */
 local void make_crc_table()
 {
-    unsigned long c;
+    z_crc_t c;
     int n, k;
-    unsigned long poly;                 /* polynomial exclusive-or pattern */
+    z_crc_t poly;                       /* polynomial exclusive-or pattern */
     /* terms of polynomial defining this crc (except x^32): */
     static volatile int first = 1;      /* flag to limit concurrent making */
     static const unsigned char p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
@@ -120,13 +100,13 @@ local void make_crc_table()
         first = 0;
 
         /* make exclusive-or pattern from polynomial (0xedb88320UL) */
-        poly = 0UL;
-        for (n = 0; n < sizeof(p)/sizeof(unsigned char); n++)
-            poly |= 1UL << (31 - p[n]);
+        poly = 0;
+        for (n = 0; n < (int)(sizeof(p)/sizeof(unsigned char)); n++)
+            poly |= (z_crc_t)1 << (31 - p[n]);
 
         /* generate a crc for every 8-bit value */
         for (n = 0; n < 256; n++) {
-            c = (unsigned long)n;
+            c = (z_crc_t)n;
             for (k = 0; k < 8; k++)
                 c = c & 1 ? poly ^ (c >> 1) : c >> 1;
             crc_table[0][n] = c;
@@ -137,11 +117,11 @@ local void make_crc_table()
            and then the byte reversal of those as well as the first table */
         for (n = 0; n < 256; n++) {
             c = crc_table[0][n];
-            crc_table[4][n] = REV(c);
+            crc_table[4][n] = ZSWAP32(c);
             for (k = 1; k < 4; k++) {
                 c = crc_table[0][c & 0xff] ^ (c >> 8);
                 crc_table[k][n] = c;
-                crc_table[k + 4][n] = REV(c);
+                crc_table[k + 4][n] = ZSWAP32(c);
             }
         }
 #endif /* BYFOUR */
@@ -163,7 +143,7 @@ local void make_crc_table()
         if (out == NULL) return;
         fprintf(out, "/* crc32.h -- tables for rapid CRC calculation\n");
         fprintf(out, " * Generated automatically by crc32.c\n */\n\n");
-        fprintf(out, "local const unsigned long FAR ");
+        fprintf(out, "local const z_crc_t FAR ");
         fprintf(out, "crc_table[TBLS][256] =\n{\n  {\n");
         write_table(out, crc_table[0]);
 #  ifdef BYFOUR
@@ -183,12 +163,13 @@ local void make_crc_table()
 #ifdef MAKECRCH
 local void write_table(out, table)
     FILE *out;
-    const unsigned long FAR *table;
+    const z_crc_t FAR *table;
 {
     int n;
 
     for (n = 0; n < 256; n++)
-        fprintf(out, "%s0x%08lxUL%s", n % 5 ? "" : "    ", table[n],
+        fprintf(out, "%s0x%08lxUL%s", n % 5 ? "" : "    ",
+                (unsigned long)(table[n]),
                 n == 255 ? "\n" : (n % 5 == 4 ? ",\n" : ", "));
 }
 #endif /* MAKECRCH */
@@ -203,13 +184,13 @@ local void write_table(out, table)
 /* =========================================================================
  * This function can be used by asm versions of crc32()
  */
-const unsigned long FAR * ZEXPORT get_crc_table()
+const z_crc_t FAR * ZEXPORT get_crc_table()
 {
 #ifdef DYNAMIC_CRC_TABLE
     if (crc_table_empty)
         make_crc_table();
 #endif /* DYNAMIC_CRC_TABLE */
-    return (const unsigned long FAR *)crc_table;
+    return (const z_crc_t FAR *)crc_table;
 }
 
 /* ========================================================================= */
@@ -217,10 +198,10 @@ const unsigned long FAR * ZEXPORT get_crc_table()
 #define DO8 DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1
 
 /* ========================================================================= */
-unsigned long ZEXPORT crc32(crc, buf, len)
+unsigned long ZEXPORT crc32_z(crc, buf, len)
     unsigned long crc;
     const unsigned char FAR *buf;
-    unsigned len;
+    z_size_t len;
 {
     if (buf == Z_NULL) return 0UL;
 
@@ -231,7 +212,7 @@ unsigned long ZEXPORT crc32(crc, buf, len)
 
 #ifdef BYFOUR
     if (sizeof(void *) == sizeof(ptrdiff_t)) {
-        u4 endian;
+        z_crc_t endian;
 
         endian = 1;
         if (*((unsigned char *)(&endian)))
@@ -251,8 +232,29 @@ unsigned long ZEXPORT crc32(crc, buf, len)
     return crc ^ 0xffffffffUL;
 }
 
+/* ========================================================================= */
+unsigned long ZEXPORT crc32(crc, buf, len)
+    unsigned long crc;
+    const unsigned char FAR *buf;
+    uInt len;
+{
+    return crc32_z(crc, buf, len);
+}
+
 #ifdef BYFOUR
 
+/*
+   This BYFOUR code accesses the passed unsigned char * buffer with a 32-bit
+   integer pointer type. This violates the strict aliasing rule, where a
+   compiler can assume, for optimization purposes, that two pointers to
+   fundamentally different types won't ever point to the same memory. This can
+   manifest as a problem only if one of the pointers is written to. This code
+   only reads from those pointers. So long as this code remains isolated in
+   this compilation unit, there won't be a problem. For this reason, this code
+   should not be copied and pasted into a compilation unit in which other code
+   writes to the buffer that is passed to these routines.
+ */
+
 /* ========================================================================= */
 #define DOLIT4 c ^= *buf4++; \
         c = crc_table[3][c & 0xff] ^ crc_table[2][(c >> 8) & 0xff] ^ \
@@ -263,19 +265,19 @@ unsigned long ZEXPORT crc32(crc, buf, len)
 local unsigned long crc32_little(crc, buf, len)
     unsigned long crc;
     const unsigned char FAR *buf;
-    unsigned len;
+    z_size_t len;
 {
-    register u4 c;
-    register const u4 FAR *buf4;
+    register z_crc_t c;
+    register const z_crc_t FAR *buf4;
 
-    c = (u4)crc;
+    c = (z_crc_t)crc;
     c = ~c;
     while (len && ((ptrdiff_t)buf & 3)) {
         c = crc_table[0][(c ^ *buf++) & 0xff] ^ (c >> 8);
         len--;
     }
 
-    buf4 = (const u4 FAR *)(const void FAR *)buf;
+    buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
     while (len >= 32) {
         DOLIT32;
         len -= 32;
@@ -294,7 +296,7 @@ local unsigned long crc32_little(crc, buf, len)
 }
 
 /* ========================================================================= */
-#define DOBIG4 c ^= *++buf4; \
+#define DOBIG4 c ^= *buf4++; \
         c = crc_table[4][c & 0xff] ^ crc_table[5][(c >> 8) & 0xff] ^ \
             crc_table[6][(c >> 16) & 0xff] ^ crc_table[7][c >> 24]
 #define DOBIG32 DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4; DOBIG4
@@ -303,20 +305,19 @@ local unsigned long crc32_little(crc, buf, len)
 local unsigned long crc32_big(crc, buf, len)
     unsigned long crc;
     const unsigned char FAR *buf;
-    unsigned len;
+    z_size_t len;
 {
-    register u4 c;
-    register const u4 FAR *buf4;
+    register z_crc_t c;
+    register const z_crc_t FAR *buf4;
 
-    c = REV((u4)crc);
+    c = ZSWAP32((z_crc_t)crc);
     c = ~c;
     while (len && ((ptrdiff_t)buf & 3)) {
         c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8);
         len--;
     }
 
-    buf4 = (const u4 FAR *)(const void FAR *)buf;
-    buf4--;
+    buf4 = (const z_crc_t FAR *)(const void FAR *)buf;
     while (len >= 32) {
         DOBIG32;
         len -= 32;
@@ -325,14 +326,13 @@ local unsigned long crc32_big(crc, buf, len)
         DOBIG4;
         len -= 4;
     }
-    buf4++;
     buf = (const unsigned char FAR *)buf4;
 
     if (len) do {
         c = crc_table[4][(c >> 24) ^ *buf++] ^ (c << 8);
     } while (--len);
     c = ~c;
-    return (unsigned long)(REV(c));
+    return (unsigned long)(ZSWAP32(c));
 }
 
 #endif /* BYFOUR */
@@ -368,22 +368,22 @@ local void gf2_matrix_square(square, mat)
 }
 
 /* ========================================================================= */
-uLong ZEXPORT crc32_combine(crc1, crc2, len2)
+local uLong crc32_combine_(crc1, crc2, len2)
     uLong crc1;
     uLong crc2;
-    z_off_t len2;
+    z_off64_t len2;
 {
     int n;
     unsigned long row;
     unsigned long even[GF2_DIM];    /* even-power-of-two zeros operator */
     unsigned long odd[GF2_DIM];     /* odd-power-of-two zeros operator */
 
-    /* degenerate case */
-    if (len2 == 0)
+    /* degenerate case (also disallow negative lengths) */
+    if (len2 <= 0)
         return crc1;
 
     /* put operator for one zero bit in odd */
-    odd[0] = 0xedb88320L;           /* CRC-32 polynomial */
+    odd[0] = 0xedb88320UL;          /* CRC-32 polynomial */
     row = 1;
     for (n = 1; n < GF2_DIM; n++) {
         odd[n] = row;
@@ -422,3 +422,20 @@ uLong ZEXPORT crc32_combine(crc1, crc2, len2)
     crc1 ^= crc2;
     return crc1;
 }
+
+/* ========================================================================= */
+uLong ZEXPORT crc32_combine(crc1, crc2, len2)
+    uLong crc1;
+    uLong crc2;
+    z_off_t len2;
+{
+    return crc32_combine_(crc1, crc2, len2);
+}
+
+uLong ZEXPORT crc32_combine64(crc1, crc2, len2)
+    uLong crc1;
+    uLong crc2;
+    z_off64_t len2;
+{
+    return crc32_combine_(crc1, crc2, len2);
+}
diff --git a/sys/lib/libz/crc32.h b/sys/lib/libz/crc32.h
index 8053b6117c0..9e0c7781025 100644
--- a/sys/lib/libz/crc32.h
+++ b/sys/lib/libz/crc32.h
@@ -2,7 +2,7 @@
  * Generated automatically by crc32.c
  */
 
-local const unsigned long FAR crc_table[TBLS][256] =
+local const z_crc_t FAR crc_table[TBLS][256] =
 {
   {
     0x00000000UL, 0x77073096UL, 0xee0e612cUL, 0x990951baUL, 0x076dc419UL,
diff --git a/sys/lib/libz/deflate.c b/sys/lib/libz/deflate.c
index 2178f312452..3247dd91975 100644
--- a/sys/lib/libz/deflate.c
+++ b/sys/lib/libz/deflate.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: deflate.c,v 1.3 2016/03/14 23:08:06 krw Exp $	*/
+/*	$OpenBSD: deflate.c,v 1.4 2021/07/04 14:24:49 tb Exp $ */
 /* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995-2005 Jean-loup Gailly.
+ * Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -38,7 +38,7 @@
  *  REFERENCES
  *
  *      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
- *      Available in http://www.ietf.org/rfc/rfc1951.txt
+ *      Available in http://tools.ietf.org/html/rfc1951
  *
  *      A description of the Rabin and Karp algorithm is given in the book
  *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
@@ -48,7 +48,6 @@
  *
  */
 
-
 #include "deflate.h"
 
 /*
@@ -71,27 +70,29 @@ typedef enum {
 typedef block_state (*compress_func) OF((deflate_state *s, int flush));
 /* Compression function. Returns the block state after the call. */
 
+local int deflateStateCheck      OF((z_streamp strm));
+local void slide_hash     OF((deflate_state *s));
 local void fill_window    OF((deflate_state *s));
 local block_state deflate_stored OF((deflate_state *s, int flush));
 local block_state deflate_fast   OF((deflate_state *s, int flush));
 #ifndef FASTEST
 local block_state deflate_slow   OF((deflate_state *s, int flush));
 #endif
+local block_state deflate_rle    OF((deflate_state *s, int flush));
+local block_state deflate_huff   OF((deflate_state *s, int flush));
 local void lm_init        OF((deflate_state *s));
 local void putShortMSB    OF((deflate_state *s, uInt b));
 local void flush_pending  OF((z_streamp strm));
-local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
-#ifndef FASTEST
+local unsigned read_buf   OF((z_streamp strm, Bytef *buf, unsigned size));
 #ifdef ASMV
+#  pragma message("Assembler code may have bugs -- use at your own risk")
       void match_init OF((void)); /* asm code initialization */
       uInt longest_match  OF((deflate_state *s, IPos cur_match));
 #else
 local uInt longest_match  OF((deflate_state *s, IPos cur_match));
 #endif
-#endif
-local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
 
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
 local  void check_match OF((deflate_state *s, IPos start, IPos match,
                             int length));
 #endif
@@ -108,11 +109,6 @@ local  void check_match OF((deflate_state *s, IPos start, IPos match,
 #endif
 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
 
-#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
-/* Minimum amount of lookahead, except at the end of the input file.
- * See deflate.c for comments about the MIN_MATCH+1.
- */
-
 /* Values for max_lazy_match, good_match and max_chain_length, depending on
  * the desired pack level (0..9). The values given below have been tuned to
  * exclude worst case performance for pathological files. Better values may be
@@ -152,18 +148,14 @@ local const config configuration_table[10] = {
  * meaning.
  */
 
-#define EQUAL 0
-/* result of memcmp for equal strings */
-
-#ifndef NO_DUMMY_DECL
-struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
-#endif
+/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
+#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))
 
 /* ===========================================================================
  * Update a hash value with the given input byte
- * IN  assertion: all calls to UPDATE_HASH are made with consecutive
- *    input characters, so that a running hash key can be computed from the
- *    previous key instead of complete recalculation each time.
+ * IN  assertion: all calls to UPDATE_HASH are made with consecutive input
+ *    characters, so that a running hash key can be computed from the previous
+ *    key instead of complete recalculation each time.
  */
 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
 
@@ -174,9 +166,9 @@ struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
  * the previous length of the hash chain.
  * If this file is compiled with -DFASTEST, the compression level is forced
  * to 1, and no hash chains are maintained.
- * IN  assertion: all calls to INSERT_STRING are made with consecutive
- *    input characters and the first MIN_MATCH bytes of str are valid
- *    (except for the last MIN_MATCH-1 bytes of the input file).
+ * IN  assertion: all calls to INSERT_STRING are made with consecutive input
+ *    characters and the first MIN_MATCH bytes of str are valid (except for
+ *    the last MIN_MATCH-1 bytes of the input file).
  */
 #ifdef FASTEST
 #define INSERT_STRING(s, str, match_head) \
@@ -198,6 +190,37 @@ struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
     s->head[s->hash_size-1] = NIL; \
     zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
 
+/* ===========================================================================
+ * Slide the hash table when sliding the window down (could be avoided with 32
+ * bit values at the expense of memory usage). We slide even when level == 0 to
+ * keep the hash table consistent if we switch back to level > 0 later.
+ */
+local void slide_hash(s)
+    deflate_state *s;
+{
+    unsigned n, m;
+    Posf *p;
+    uInt wsize = s->w_size;
+
+    n = s->hash_size;
+    p = &s->head[n];
+    do {
+        m = *--p;
+        *p = (Pos)(m >= wsize ? m - wsize : NIL);
+    } while (--n);
+    n = wsize;
+#ifndef FASTEST
+    p = &s->prev[n];
+    do {
+        m = *--p;
+        *p = (Pos)(m >= wsize ? m - wsize : NIL);
+        /* If n is not on any hash chain, prev[n] is garbage but
+         * its value will never be used.
+         */
+    } while (--n);
+#endif
+}
+
 /* ========================================================================= */
 int ZEXPORT deflateInit_(strm, level, version, stream_size)
     z_streamp strm;
@@ -239,10 +262,19 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
 
     strm->msg = Z_NULL;
     if (strm->zalloc == (alloc_func)0) {
+#ifdef Z_SOLO
+        return Z_STREAM_ERROR;
+#else
         strm->zalloc = zcalloc;
         strm->opaque = (voidpf)0;
+#endif
     }
-    if (strm->zfree == (free_func)0) strm->zfree = zcfree;
+    if (strm->zfree == (free_func)0)
+#ifdef Z_SOLO
+        return Z_STREAM_ERROR;
+#else
+        strm->zfree = zcfree;
+#endif
 
 #ifdef FASTEST
     if (level != 0) level = 1;
@@ -262,7 +294,7 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
 #endif
     if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
         windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
-        strategy < 0 || strategy > Z_FIXED) {
+        strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) {
         return Z_STREAM_ERROR;
     }
     if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */
@@ -270,14 +302,15 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     if (s == Z_NULL) return Z_MEM_ERROR;
     strm->state = (struct internal_state FAR *)s;
     s->strm = strm;
+    s->status = INIT_STATE;     /* to pass state test in deflateReset() */
 
     s->wrap = wrap;
     s->gzhead = Z_NULL;
-    s->w_bits = windowBits;
+    s->w_bits = (uInt)windowBits;
     s->w_size = 1 << s->w_bits;
     s->w_mask = s->w_size - 1;
 
-    s->hash_bits = memLevel + 7;
+    s->hash_bits = (uInt)memLevel + 7;
     s->hash_size = 1 << s->hash_bits;
     s->hash_mask = s->hash_size - 1;
     s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
@@ -286,6 +319,8 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
 
+    s->high_water = 0;      /* nothing written to s->window yet */
+
     s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
 
     overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
@@ -295,7 +330,7 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
         s->pending_buf == Z_NULL) {
         s->status = FINISH_STATE;
-        strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
+        strm->msg = ERR_MSG(Z_MEM_ERROR);
         deflateEnd (strm);
         return Z_MEM_ERROR;
     }
@@ -309,6 +344,31 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     return deflateReset(strm);
 }
 
+/* =========================================================================
+ * Check for a valid deflate stream state. Return 0 if ok, 1 if not.
+ */
+local int deflateStateCheck (strm)
+    z_streamp strm;
+{
+    deflate_state *s;
+    if (strm == Z_NULL ||
+        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
+        return 1;
+    s = strm->state;
+    if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
+#ifdef GZIP
+                                           s->status != GZIP_STATE &&
+#endif
+                                           s->status != EXTRA_STATE &&
+                                           s->status != NAME_STATE &&
+                                           s->status != COMMENT_STATE &&
+                                           s->status != HCRC_STATE &&
+                                           s->status != BUSY_STATE &&
+                                           s->status != FINISH_STATE))
+        return 1;
+    return 0;
+}
+
 /* ========================================================================= */
 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
     z_streamp strm;
@@ -316,49 +376,97 @@ int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
     uInt  dictLength;
 {
     deflate_state *s;
-    uInt length = dictLength;
-    uInt n;
-    IPos hash_head = 0;
+    uInt str, n;
+    int wrap;
+    unsigned avail;
+    z_const unsigned char *next;
 
-    if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
-        strm->state->wrap == 2 ||
-        (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
+    if (deflateStateCheck(strm) || dictionary == Z_NULL)
         return Z_STREAM_ERROR;
-
     s = strm->state;
-    if (s->wrap)
-        strm->adler = adler32(strm->adler, dictionary, dictLength);
+    wrap = s->wrap;
+    if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
+        return Z_STREAM_ERROR;
 
-    if (length < MIN_MATCH) return Z_OK;
-    if (length > MAX_DIST(s)) {
-        length = MAX_DIST(s);
-        dictionary += dictLength - length; /* use the tail of the dictionary */
+    /* when using zlib wrappers, compute Adler-32 for provided dictionary */
+    if (wrap == 1)
+        strm->adler = adler32(strm->adler, dictionary, dictLength);
+    s->wrap = 0;                    /* avoid computing Adler-32 in read_buf */
+
+    /* if dictionary would fill window, just replace the history */
+    if (dictLength >= s->w_size) {
+        if (wrap == 0) {            /* already empty otherwise */
+            CLEAR_HASH(s);
+            s->strstart = 0;
+            s->block_start = 0L;
+            s->insert = 0;
+        }
+        dictionary += dictLength - s->w_size;  /* use the tail */
+        dictLength = s->w_size;
     }
-    zmemcpy(s->window, dictionary, length);
-    s->strstart = length;
-    s->block_start = (long)length;
 
-    /* Insert all strings in the hash table (except for the last two bytes).
-     * s->lookahead stays null, so s->ins_h will be recomputed at the next
-     * call of fill_window.
-     */
-    s->ins_h = s->window[0];
-    UPDATE_HASH(s, s->ins_h, s->window[1]);
-    for (n = 0; n <= length - MIN_MATCH; n++) {
-        INSERT_STRING(s, n, hash_head);
+    /* insert dictionary into window and hash */
+    avail = strm->avail_in;
+    next = strm->next_in;
+    strm->avail_in = dictLength;
+    strm->next_in = (z_const Bytef *)dictionary;
+    fill_window(s);
+    while (s->lookahead >= MIN_MATCH) {
+        str = s->strstart;
+        n = s->lookahead - (MIN_MATCH-1);
+        do {
+            UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
+#ifndef FASTEST
+            s->prev[str & s->w_mask] = s->head[s->ins_h];
+#endif
+            s->head[s->ins_h] = (Pos)str;
+            str++;
+        } while (--n);
+        s->strstart = str;
+        s->lookahead = MIN_MATCH-1;
+        fill_window(s);
     }
-    if (hash_head) hash_head = 0;  /* to make compiler happy */
+    s->strstart += s->lookahead;
+    s->block_start = (long)s->strstart;
+    s->insert = s->lookahead;
+    s->lookahead = 0;
+    s->match_length = s->prev_length = MIN_MATCH-1;
+    s->match_available = 0;
+    strm->next_in = next;
+    strm->avail_in = avail;
+    s->wrap = wrap;
     return Z_OK;
 }
 
 /* ========================================================================= */
-int ZEXPORT deflateReset (strm)
+int ZEXPORT deflateGetDictionary (strm, dictionary, dictLength)
+    z_streamp strm;
+    Bytef *dictionary;
+    uInt  *dictLength;
+{
+    deflate_state *s;
+    uInt len;
+
+    if (deflateStateCheck(strm))
+        return Z_STREAM_ERROR;
+    s = strm->state;
+    len = s->strstart + s->lookahead;
+    if (len > s->w_size)
+        len = s->w_size;
+    if (dictionary != Z_NULL && len)
+        zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
+    if (dictLength != Z_NULL)
+        *dictLength = len;
+    return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateResetKeep (strm)
     z_streamp strm;
 {
     deflate_state *s;
 
-    if (strm == Z_NULL || strm->state == Z_NULL ||
-        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
+    if (deflateStateCheck(strm)) {
         return Z_STREAM_ERROR;
     }
 
@@ -373,7 +481,11 @@ int ZEXPORT deflateReset (strm)
     if (s->wrap < 0) {
         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
     }
-    s->status = s->wrap ? INIT_STATE : BUSY_STATE;
+    s->status =
+#ifdef GZIP
+        s->wrap == 2 ? GZIP_STATE :
+#endif
+        s->wrap ? INIT_STATE : BUSY_STATE;
     strm->adler =
 #ifdef GZIP
         s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
@@ -382,31 +494,70 @@ int ZEXPORT deflateReset (strm)
     s->last_flush = Z_NO_FLUSH;
 
     _tr_init(s);
-    lm_init(s);
 
     return Z_OK;
 }
 
 /* ========================================================================= */
+int ZEXPORT deflateReset (strm)
+    z_streamp strm;
+{
+    int ret;
+
+    ret = deflateResetKeep(strm);
+    if (ret == Z_OK)
+        lm_init(strm->state);
+    return ret;
+}
+
+/* ========================================================================= */
 int ZEXPORT deflateSetHeader (strm, head)
     z_streamp strm;
     gz_headerp head;
 {
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
-    if (strm->state->wrap != 2) return Z_STREAM_ERROR;
+    if (deflateStateCheck(strm) || strm->state->wrap != 2)
+        return Z_STREAM_ERROR;
     strm->state->gzhead = head;
     return Z_OK;
 }
 
 /* ========================================================================= */
+int ZEXPORT deflatePending (strm, pending, bits)
+    unsigned *pending;
+    int *bits;
+    z_streamp strm;
+{
+    if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+    if (pending != Z_NULL)
+        *pending = strm->state->pending;
+    if (bits != Z_NULL)
+        *bits = strm->state->bi_valid;
+    return Z_OK;
+}
+
+/* ========================================================================= */
 int ZEXPORT deflatePrime (strm, bits, value)
     z_streamp strm;
     int bits;
     int value;
 {
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
-    strm->state->bi_valid = bits;
-    strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
+    deflate_state *s;
+    int put;
+
+    if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+    s = strm->state;
+    if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))
+        return Z_BUF_ERROR;
+    do {
+        put = Buf_size - s->bi_valid;
+        if (put > bits)
+            put = bits;
+        s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
+        s->bi_valid += put;
+        _tr_flush_bits(s);
+        value >>= put;
+        bits -= put;
+    } while (bits);
     return Z_OK;
 }
 
@@ -418,9 +569,8 @@ int ZEXPORT deflateParams(strm, level, strategy)
 {
     deflate_state *s;
     compress_func func;
-    int err = Z_OK;
 
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
     s = strm->state;
 
 #ifdef FASTEST
@@ -433,11 +583,23 @@ int ZEXPORT deflateParams(strm, level, strategy)
     }
     func = configuration_table[s->level].func;
 
-    if (func != configuration_table[level].func && strm->total_in != 0) {
+    if ((strategy != s->strategy || func != configuration_table[level].func) &&
+        s->high_water) {
         /* Flush the last buffer: */
-        err = deflate(strm, Z_PARTIAL_FLUSH);
+        int err = deflate(strm, Z_BLOCK);
+        if (err == Z_STREAM_ERROR)
+            return err;
+        if (strm->avail_out == 0)
+            return Z_BUF_ERROR;
     }
     if (s->level != level) {
+        if (s->level == 0 && s->matches != 0) {
+            if (s->matches == 1)
+                slide_hash(s);
+            else
+                CLEAR_HASH(s);
+            s->matches = 0;
+        }
         s->level = level;
         s->max_lazy_match   = configuration_table[level].max_lazy;
         s->good_match       = configuration_table[level].good_length;
@@ -445,7 +607,7 @@ int ZEXPORT deflateParams(strm, level, strategy)
         s->max_chain_length = configuration_table[level].max_chain;
     }
     s->strategy = strategy;
-    return err;
+    return Z_OK;
 }
 
 /* ========================================================================= */
@@ -458,12 +620,12 @@ int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
 {
     deflate_state *s;
 
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
     s = strm->state;
-    s->good_match = good_length;
-    s->max_lazy_match = max_lazy;
+    s->good_match = (uInt)good_length;
+    s->max_lazy_match = (uInt)max_lazy;
     s->nice_match = nice_length;
-    s->max_chain_length = max_chain;
+    s->max_chain_length = (uInt)max_chain;
     return Z_OK;
 }
 
@@ -479,33 +641,68 @@ int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
  * resulting from using fixed blocks instead of stored blocks, which deflate
  * can emit on compressed data for some combinations of the parameters.
  *
- * This function could be more sophisticated to provide closer upper bounds
- * for every combination of windowBits and memLevel, as well as wrap.
- * But even the conservative upper bound of about 14% expansion does not
- * seem onerous for output buffer allocation.
+ * This function could be more sophisticated to provide closer upper bounds for
+ * every combination of windowBits and memLevel.  But even the conservative
+ * upper bound of about 14% expansion does not seem onerous for output buffer
+ * allocation.
  */
 uLong ZEXPORT deflateBound(strm, sourceLen)
     z_streamp strm;
     uLong sourceLen;
 {
     deflate_state *s;
-    uLong destLen;
+    uLong complen, wraplen;
 
-    /* conservative upper bound */
-    destLen = sourceLen +
-              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
+    /* conservative upper bound for compressed data */
+    complen = sourceLen +
+              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
 
-    /* if can't get parameters, return conservative bound */
-    if (strm == Z_NULL || strm->state == Z_NULL)
-        return destLen;
+    /* if can't get parameters, return conservative bound plus zlib wrapper */
+    if (deflateStateCheck(strm))
+        return complen + 6;
 
-    /* if not default parameters, return conservative bound */
+    /* compute wrapper length */
     s = strm->state;
+    switch (s->wrap) {
+    case 0:                                 /* raw deflate */
+        wraplen = 0;
+        break;
+    case 1:                                 /* zlib wrapper */
+        wraplen = 6 + (s->strstart ? 4 : 0);
+        break;
+#ifdef GZIP
+    case 2:                                 /* gzip wrapper */
+        wraplen = 18;
+        if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */
+            Bytef *str;
+            if (s->gzhead->extra != Z_NULL)
+                wraplen += 2 + s->gzhead->extra_len;
+            str = s->gzhead->name;
+            if (str != Z_NULL)
+                do {
+                    wraplen++;
+                } while (*str++);
+            str = s->gzhead->comment;
+            if (str != Z_NULL)
+                do {
+                    wraplen++;
+                } while (*str++);
+            if (s->gzhead->hcrc)
+                wraplen += 2;
+        }
+        break;
+#endif
+    default:                                /* for compiler happiness */
+        wraplen = 6;
+    }
+
+    /* if not default parameters, return conservative bound */
     if (s->w_bits != 15 || s->hash_bits != 8 + 7)
-        return destLen;
+        return complen + wraplen;
 
     /* default settings: return tight bound for that case */
-    return compressBound(sourceLen);
+    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
+           (sourceLen >> 25) + 13 - 6 + wraplen;
 }
 
 /* =========================================================================
@@ -522,30 +719,43 @@ local void putShortMSB (s, b)
 }
 
 /* =========================================================================
- * Flush as much pending output as possible. All deflate() output goes
- * through this function so some applications may wish to modify it
- * to avoid allocating a large strm->next_out buffer and copying into it.
- * (See also read_buf()).
+ * Flush as much pending output as possible. All deflate() output, except for
+ * some deflate_stored() output, goes through this function so some
+ * applications may wish to modify it to avoid allocating a large
+ * strm->next_out buffer and copying into it. (See also read_buf()).
  */
 local void flush_pending(strm)
     z_streamp strm;
 {
-    unsigned len = strm->state->pending;
+    unsigned len;
+    deflate_state *s = strm->state;
 
+    _tr_flush_bits(s);
+    len = s->pending;
     if (len > strm->avail_out) len = strm->avail_out;
     if (len == 0) return;
 
-    zmemcpy(strm->next_out, strm->state->pending_out, len);
+    zmemcpy(strm->next_out, s->pending_out, len);
     strm->next_out  += len;
-    strm->state->pending_out  += len;
+    s->pending_out  += len;
     strm->total_out += len;
-    strm->avail_out  -= len;
-    strm->state->pending -= len;
-    if (strm->state->pending == 0) {
-        strm->state->pending_out = strm->state->pending_buf;
+    strm->avail_out -= len;
+    s->pending      -= len;
+    if (s->pending == 0) {
+        s->pending_out = s->pending_buf;
     }
 }
 
+/* ===========================================================================
+ * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1].
+ */
+#define HCRC_UPDATE(beg) \
+    do { \
+        if (s->gzhead->hcrc && s->pending > (beg)) \
+            strm->adler = crc32(strm->adler, s->pending_buf + (beg), \
+                                s->pending - (beg)); \
+    } while (0)
+
 /* ========================================================================= */
 int ZEXPORT deflate (strm, flush)
     z_streamp strm;
@@ -554,230 +764,229 @@ int ZEXPORT deflate (strm, flush)
     int old_flush; /* value of flush param for previous deflate call */
     deflate_state *s;
 
-    if (strm == Z_NULL || strm->state == Z_NULL ||
-        flush > Z_FINISH || flush < 0) {
+    if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
         return Z_STREAM_ERROR;
     }
     s = strm->state;
 
     if (strm->next_out == Z_NULL ||
-        (strm->next_in == Z_NULL && strm->avail_in != 0) ||
+        (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
         (s->status == FINISH_STATE && flush != Z_FINISH)) {
         ERR_RETURN(strm, Z_STREAM_ERROR);
     }
     if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
 
-    s->strm = strm; /* just in case */
     old_flush = s->last_flush;
     s->last_flush = flush;
 
+    /* Flush as much pending output as possible */
+    if (s->pending != 0) {
+        flush_pending(strm);
+        if (strm->avail_out == 0) {
+            /* Since avail_out is 0, deflate will be called again with
+             * more output space, but possibly with both pending and
+             * avail_in equal to zero. There won't be anything to do,
+             * but this is not an error situation so make sure we
+             * return OK instead of BUF_ERROR at next call of deflate:
+             */
+            s->last_flush = -1;
+            return Z_OK;
+        }
+
+    /* Make sure there is something to do and avoid duplicate consecutive
+     * flushes. For repeated and useless calls with Z_FINISH, we keep
+     * returning Z_STREAM_END instead of Z_BUF_ERROR.
+     */
+    } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
+               flush != Z_FINISH) {
+        ERR_RETURN(strm, Z_BUF_ERROR);
+    }
+
+    /* User must not provide more input after the first FINISH: */
+    if (s->status == FINISH_STATE && strm->avail_in != 0) {
+        ERR_RETURN(strm, Z_BUF_ERROR);
+    }
+
     /* Write the header */
     if (s->status == INIT_STATE) {
-#ifdef GZIP
-        if (s->wrap == 2) {
-            strm->adler = crc32(0L, Z_NULL, 0);
-            put_byte(s, 31);
-            put_byte(s, 139);
-            put_byte(s, 8);
-            if (s->gzhead == NULL) {
-                put_byte(s, 0);
-                put_byte(s, 0);
-                put_byte(s, 0);
-                put_byte(s, 0);
-                put_byte(s, 0);
-                put_byte(s, s->level == 9 ? 2 :
-                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
-                             4 : 0));
-                put_byte(s, OS_CODE);
-                s->status = BUSY_STATE;
-            }
-            else {
-                put_byte(s, (s->gzhead->text ? 1 : 0) +
-                            (s->gzhead->hcrc ? 2 : 0) +
-                            (s->gzhead->extra == Z_NULL ? 0 : 4) +
-                            (s->gzhead->name == Z_NULL ? 0 : 8) +
-                            (s->gzhead->comment == Z_NULL ? 0 : 16)
-                        );
-                put_byte(s, (Byte)(s->gzhead->time & 0xff));
-                put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
-                put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
-                put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
-                put_byte(s, s->level == 9 ? 2 :
-                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
-                             4 : 0));
-                put_byte(s, s->gzhead->os & 0xff);
-                if (s->gzhead->extra != NULL) {
-                    put_byte(s, s->gzhead->extra_len & 0xff);
-                    put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
-                }
-                if (s->gzhead->hcrc)
-                    strm->adler = crc32(strm->adler, s->pending_buf,
-                                        s->pending);
-                s->gzindex = 0;
-                s->status = EXTRA_STATE;
-            }
-        }
+        /* zlib header */
+        uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
+        uInt level_flags;
+
+        if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
+            level_flags = 0;
+        else if (s->level < 6)
+            level_flags = 1;
+        else if (s->level == 6)
+            level_flags = 2;
         else
-#endif
-        {
-            uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
-            uInt level_flags;
-
-            if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
-                level_flags = 0;
-            else if (s->level < 6)
-                level_flags = 1;
-            else if (s->level == 6)
-                level_flags = 2;
-            else
-                level_flags = 3;
-            header |= (level_flags << 6);
-            if (s->strstart != 0) header |= PRESET_DICT;
-            header += 31 - (header % 31);
+            level_flags = 3;
+        header |= (level_flags << 6);
+        if (s->strstart != 0) header |= PRESET_DICT;
+        header += 31 - (header % 31);
 
+        putShortMSB(s, header);
+
+        /* Save the adler32 of the preset dictionary: */
+        if (s->strstart != 0) {
+            putShortMSB(s, (uInt)(strm->adler >> 16));
+            putShortMSB(s, (uInt)(strm->adler & 0xffff));
+        }
+        strm->adler = adler32(0L, Z_NULL, 0);
+        s->status = BUSY_STATE;
+
+        /* Compression must start with an empty pending buffer */
+        flush_pending(strm);
+        if (s->pending != 0) {
+            s->last_flush = -1;
+            return Z_OK;
+        }
+    }
+#ifdef GZIP
+    if (s->status == GZIP_STATE) {
+        /* gzip header */
+        strm->adler = crc32(0L, Z_NULL, 0);
+        put_byte(s, 31);
+        put_byte(s, 139);
+        put_byte(s, 8);
+        if (s->gzhead == Z_NULL) {
+            put_byte(s, 0);
+            put_byte(s, 0);
+            put_byte(s, 0);
+            put_byte(s, 0);
+            put_byte(s, 0);
+            put_byte(s, s->level == 9 ? 2 :
+                     (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
+                      4 : 0));
+            put_byte(s, OS_CODE);
             s->status = BUSY_STATE;
-            putShortMSB(s, header);
 
-            /* Save the adler32 of the preset dictionary: */
-            if (s->strstart != 0) {
-                putShortMSB(s, (uInt)(strm->adler >> 16));
-                putShortMSB(s, (uInt)(strm->adler & 0xffff));
+            /* Compression must start with an empty pending buffer */
+            flush_pending(strm);
+            if (s->pending != 0) {
+                s->last_flush = -1;
+                return Z_OK;
             }
-            strm->adler = adler32(0L, Z_NULL, 0);
+        }
+        else {
+            put_byte(s, (s->gzhead->text ? 1 : 0) +
+                     (s->gzhead->hcrc ? 2 : 0) +
+                     (s->gzhead->extra == Z_NULL ? 0 : 4) +
+                     (s->gzhead->name == Z_NULL ? 0 : 8) +
+                     (s->gzhead->comment == Z_NULL ? 0 : 16)
+                     );
+            put_byte(s, (Byte)(s->gzhead->time & 0xff));
+            put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
+            put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
+            put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
+            put_byte(s, s->level == 9 ? 2 :
+                     (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
+                      4 : 0));
+            put_byte(s, s->gzhead->os & 0xff);
+            if (s->gzhead->extra != Z_NULL) {
+                put_byte(s, s->gzhead->extra_len & 0xff);
+                put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
+            }
+            if (s->gzhead->hcrc)
+                strm->adler = crc32(strm->adler, s->pending_buf,
+                                    s->pending);
+            s->gzindex = 0;
+            s->status = EXTRA_STATE;
         }
     }
-#ifdef GZIP
     if (s->status == EXTRA_STATE) {
-        if (s->gzhead->extra != NULL) {
-            uInt beg = s->pending;  /* start of bytes to update crc */
-
-            while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
-                if (s->pending == s->pending_buf_size) {
-                    if (s->gzhead->hcrc && s->pending > beg)
-                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
-                                            s->pending - beg);
-                    flush_pending(strm);
-                    beg = s->pending;
-                    if (s->pending == s->pending_buf_size)
-                        break;
+        if (s->gzhead->extra != Z_NULL) {
+            ulg beg = s->pending;   /* start of bytes to update crc */
+            uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
+            while (s->pending + left > s->pending_buf_size) {
+                uInt copy = s->pending_buf_size - s->pending;
+                zmemcpy(s->pending_buf + s->pending,
+                        s->gzhead->extra + s->gzindex, copy);
+                s->pending = s->pending_buf_size;
+                HCRC_UPDATE(beg);
+                s->gzindex += copy;
+                flush_pending(strm);
+                if (s->pending != 0) {
+                    s->last_flush = -1;
+                    return Z_OK;
                 }
-                put_byte(s, s->gzhead->extra[s->gzindex]);
-                s->gzindex++;
-            }
-            if (s->gzhead->hcrc && s->pending > beg)
-                strm->adler = crc32(strm->adler, s->pending_buf + beg,
-                                    s->pending - beg);
-            if (s->gzindex == s->gzhead->extra_len) {
-                s->gzindex = 0;
-                s->status = NAME_STATE;
+                beg = 0;
+                left -= copy;
             }
+            zmemcpy(s->pending_buf + s->pending,
+                    s->gzhead->extra + s->gzindex, left);
+            s->pending += left;
+            HCRC_UPDATE(beg);
+            s->gzindex = 0;
         }
-        else
-            s->status = NAME_STATE;
+        s->status = NAME_STATE;
     }
     if (s->status == NAME_STATE) {
-        if (s->gzhead->name != NULL) {
-            uInt beg = s->pending;  /* start of bytes to update crc */
+        if (s->gzhead->name != Z_NULL) {
+            ulg beg = s->pending;   /* start of bytes to update crc */
             int val;
-
             do {
                 if (s->pending == s->pending_buf_size) {
-                    if (s->gzhead->hcrc && s->pending > beg)
-                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
-                                            s->pending - beg);
+                    HCRC_UPDATE(beg);
                     flush_pending(strm);
-                    beg = s->pending;
-                    if (s->pending == s->pending_buf_size) {
-                        val = 1;
-                        break;
+                    if (s->pending != 0) {
+                        s->last_flush = -1;
+                        return Z_OK;
                     }
+                    beg = 0;
                 }
                 val = s->gzhead->name[s->gzindex++];
                 put_byte(s, val);
             } while (val != 0);
-            if (s->gzhead->hcrc && s->pending > beg)
-                strm->adler = crc32(strm->adler, s->pending_buf + beg,
-                                    s->pending - beg);
-            if (val == 0) {
-                s->gzindex = 0;
-                s->status = COMMENT_STATE;
-            }
+            HCRC_UPDATE(beg);
+            s->gzindex = 0;
         }
-        else
-            s->status = COMMENT_STATE;
+        s->status = COMMENT_STATE;
     }
     if (s->status == COMMENT_STATE) {
-        if (s->gzhead->comment != NULL) {
-            uInt beg = s->pending;  /* start of bytes to update crc */
+        if (s->gzhead->comment != Z_NULL) {
+            ulg beg = s->pending;   /* start of bytes to update crc */
             int val;
-
             do {
                 if (s->pending == s->pending_buf_size) {
-                    if (s->gzhead->hcrc && s->pending > beg)
-                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
-                                            s->pending - beg);
+                    HCRC_UPDATE(beg);
                     flush_pending(strm);
-                    beg = s->pending;
-                    if (s->pending == s->pending_buf_size) {
-                        val = 1;
-                        break;
+                    if (s->pending != 0) {
+                        s->last_flush = -1;
+                        return Z_OK;
                     }
+                    beg = 0;
                 }
                 val = s->gzhead->comment[s->gzindex++];
                 put_byte(s, val);
             } while (val != 0);
-            if (s->gzhead->hcrc && s->pending > beg)
-                strm->adler = crc32(strm->adler, s->pending_buf + beg,
-                                    s->pending - beg);
-            if (val == 0)
-                s->status = HCRC_STATE;
+            HCRC_UPDATE(beg);
         }
-        else
-            s->status = HCRC_STATE;
+        s->status = HCRC_STATE;
     }
     if (s->status == HCRC_STATE) {
         if (s->gzhead->hcrc) {
-            if (s->pending + 2 > s->pending_buf_size)
+            if (s->pending + 2 > s->pending_buf_size) {
                 flush_pending(strm);
-            if (s->pending + 2 <= s->pending_buf_size) {
-                put_byte(s, (Byte)(strm->adler & 0xff));
-                put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
-                strm->adler = crc32(0L, Z_NULL, 0);
-                s->status = BUSY_STATE;
+                if (s->pending != 0) {
+                    s->last_flush = -1;
+                    return Z_OK;
+                }
             }
+            put_byte(s, (Byte)(strm->adler & 0xff));
+            put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
+            strm->adler = crc32(0L, Z_NULL, 0);
         }
-        else
-            s->status = BUSY_STATE;
-    }
-#endif
+        s->status = BUSY_STATE;
 
-    /* Flush as much pending output as possible */
-    if (s->pending != 0) {
+        /* Compression must start with an empty pending buffer */
         flush_pending(strm);
-        if (strm->avail_out == 0) {
-            /* Since avail_out is 0, deflate will be called again with
-             * more output space, but possibly with both pending and
-             * avail_in equal to zero. There won't be anything to do,
-             * but this is not an error situation so make sure we
-             * return OK instead of BUF_ERROR at next call of deflate:
-             */
+        if (s->pending != 0) {
             s->last_flush = -1;
             return Z_OK;
         }
-
-    /* Make sure there is something to do and avoid duplicate consecutive
-     * flushes. For repeated and useless calls with Z_FINISH, we keep
-     * returning Z_STREAM_END instead of Z_BUF_ERROR.
-     */
-    } else if (strm->avail_in == 0 && flush <= old_flush &&
-               flush != Z_FINISH) {
-        ERR_RETURN(strm, Z_BUF_ERROR);
-    }
-
-    /* User must not provide more input after the first FINISH: */
-    if (s->status == FINISH_STATE && strm->avail_in != 0) {
-        ERR_RETURN(strm, Z_BUF_ERROR);
     }
+#endif
 
     /* Start a new block or continue the current one.
      */
@@ -785,7 +994,10 @@ int ZEXPORT deflate (strm, flush)
         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
         block_state bstate;
 
-        bstate = (*(configuration_table[s->level].func))(s, flush);
+        bstate = s->level == 0 ? deflate_stored(s, flush) :
+                 s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
+                 s->strategy == Z_RLE ? deflate_rle(s, flush) :
+                 (*(configuration_table[s->level].func))(s, flush);
 
         if (bstate == finish_started || bstate == finish_done) {
             s->status = FINISH_STATE;
@@ -806,13 +1018,18 @@ int ZEXPORT deflate (strm, flush)
         if (bstate == block_done) {
             if (flush == Z_PARTIAL_FLUSH) {
                 _tr_align(s);
-            } else { /* FULL_FLUSH or SYNC_FLUSH */
-                _tr_stored_block(s, NULL, 0L, 0);
+            } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
+                _tr_stored_block(s, (char*)0, 0L, 0);
                 /* For a full flush, this empty block will be recognized
                  * as a special marker by inflate_sync().
                  */
                 if (flush == Z_FULL_FLUSH) {
                     CLEAR_HASH(s);             /* forget history */
+                    if (s->lookahead == 0) {
+                        s->strstart = 0;
+                        s->block_start = 0L;
+                        s->insert = 0;
+                    }
                 }
             }
             flush_pending(strm);
@@ -822,7 +1039,6 @@ int ZEXPORT deflate (strm, flush)
             }
         }
     }
-    Assert(strm->avail_out > 0, "bug2");
 
     if (flush != Z_FINISH) return Z_OK;
     if (s->wrap <= 0) return Z_STREAM_END;
@@ -859,18 +1075,9 @@ int ZEXPORT deflateEnd (strm)
 {
     int status;
 
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
 
     status = strm->state->status;
-    if (status != INIT_STATE &&
-        status != EXTRA_STATE &&
-        status != NAME_STATE &&
-        status != COMMENT_STATE &&
-        status != HCRC_STATE &&
-        status != BUSY_STATE &&
-        status != FINISH_STATE) {
-      return Z_STREAM_ERROR;
-    }
 
     /* Deallocate in reverse order of allocations: */
     TRY_FREE(strm, strm->state->pending_buf);
@@ -901,18 +1108,18 @@ int ZEXPORT deflateCopy (dest, source)
     ushf *overlay;
 
 
-    if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
+    if (deflateStateCheck(source) || dest == Z_NULL) {
         return Z_STREAM_ERROR;
     }
 
     ss = source->state;
 
-    zmemcpy(dest, source, sizeof(z_stream));
+    zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
 
     ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
     if (ds == Z_NULL) return Z_MEM_ERROR;
     dest->state = (struct internal_state FAR *) ds;
-    zmemcpy(ds, ss, sizeof(deflate_state));
+    zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
     ds->strm = dest;
 
     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
@@ -928,8 +1135,8 @@ int ZEXPORT deflateCopy (dest, source)
     }
     /* following zmemcpy do not work for 16-bit MSDOS */
     zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
-    zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
-    zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
+    zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
+    zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
 
     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
@@ -951,7 +1158,7 @@ int ZEXPORT deflateCopy (dest, source)
  * allocating a large strm->next_in buffer and copying from it.
  * (See also flush_pending()).
  */
-local int read_buf(strm, buf, size)
+local unsigned read_buf(strm, buf, size)
     z_streamp strm;
     Bytef *buf;
     unsigned size;
@@ -963,19 +1170,19 @@ local int read_buf(strm, buf, size)
 
     strm->avail_in  -= len;
 
+    zmemcpy(buf, strm->next_in, len);
     if (strm->state->wrap == 1) {
-        strm->adler = adler32(strm->adler, strm->next_in, len);
+        strm->adler = adler32(strm->adler, buf, len);
     }
 #ifdef GZIP
     else if (strm->state->wrap == 2) {
-        strm->adler = crc32(strm->adler, strm->next_in, len);
+        strm->adler = crc32(strm->adler, buf, len);
     }
 #endif
-    zmemcpy(buf, strm->next_in, len);
     strm->next_in  += len;
     strm->total_in += len;
 
-    return (int)len;
+    return len;
 }
 
 /* ===========================================================================
@@ -998,6 +1205,7 @@ local void lm_init (s)
     s->strstart = 0;
     s->block_start = 0L;
     s->lookahead = 0;
+    s->insert = 0;
     s->match_length = s->prev_length = MIN_MATCH-1;
     s->match_available = 0;
     s->ins_h = 0;
@@ -1028,9 +1236,9 @@ local uInt longest_match(s, cur_match)
 {
     unsigned chain_length = s->max_chain_length;/* max hash chain length */
     register Bytef *scan = s->window + s->strstart; /* current string */
-    register Bytef *match;                       /* matched string */
+    register Bytef *match;                      /* matched string */
     register int len;                           /* length of current match */
-    int best_len = s->prev_length;              /* best match length so far */
+    int best_len = (int)s->prev_length;         /* best match length so far */
     int nice_match = s->nice_match;             /* stop if match long enough */
     IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
         s->strstart - (IPos)MAX_DIST(s) : NIL;
@@ -1065,7 +1273,7 @@ local uInt longest_match(s, cur_match)
     /* Do not look for matches beyond the end of the input. This is necessary
      * to make deflate deterministic.
      */
-    if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
+    if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead;
 
     Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
 
@@ -1165,12 +1373,13 @@ local uInt longest_match(s, cur_match)
     return s->lookahead;
 }
 #endif /* ASMV */
-#endif /* FASTEST */
+
+#else /* FASTEST */
 
 /* ---------------------------------------------------------------------------
- * Optimized version for level == 1 or strategy == Z_RLE only
+ * Optimized version for FASTEST only
  */
-local uInt longest_match_fast(s, cur_match)
+local uInt longest_match(s, cur_match)
     deflate_state *s;
     IPos cur_match;                             /* current match */
 {
@@ -1223,7 +1432,13 @@ local uInt longest_match_fast(s, cur_match)
     return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
 }
 
-#ifdef DEBUG_LIBZ
+#endif /* FASTEST */
+
+#ifdef ZLIB_DEBUG
+
+#define EQUAL 0
+/* result of memcmp for equal strings */
+
 /* ===========================================================================
  * Check that the match at match_start is indeed a match.
  */
@@ -1249,7 +1464,7 @@ local void check_match(s, start, match, length)
 }
 #else
 #  define check_match(s, start, match, length)
-#endif /* DEBUG_LIBZ */
+#endif /* ZLIB_DEBUG */
 
 /* ===========================================================================
  * Fill the window when the lookahead becomes insufficient.
@@ -1264,11 +1479,12 @@ local void check_match(s, start, match, length)
 local void fill_window(s)
     deflate_state *s;
 {
-    register unsigned n, m;
-    register Posf *p;
+    unsigned n;
     unsigned more;    /* Amount of free space at the end of the window. */
     uInt wsize = s->w_size;
 
+    Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
+
     do {
         more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
 
@@ -1290,39 +1506,14 @@ local void fill_window(s)
          */
         if (s->strstart >= wsize+MAX_DIST(s)) {
 
-            zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
+            zmemcpy(s->window, s->window+wsize, (unsigned)wsize - more);
             s->match_start -= wsize;
             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
             s->block_start -= (long) wsize;
-
-            /* Slide the hash table (could be avoided with 32 bit values
-               at the expense of memory usage). We slide even when level == 0
-               to keep the hash table consistent if we switch back to level > 0
-               later. (Using level 0 permanently is not an optimal usage of
-               zlib, so we don't care about this pathological case.)
-             */
-            /* %%% avoid this when Z_RLE */
-            n = s->hash_size;
-            p = &s->head[n];
-            do {
-                m = *--p;
-                *p = (Pos)(m >= wsize ? m-wsize : NIL);
-            } while (--n);
-
-            n = wsize;
-#ifndef FASTEST
-            p = &s->prev[n];
-            do {
-                m = *--p;
-                *p = (Pos)(m >= wsize ? m-wsize : NIL);
-                /* If n is not on any hash chain, prev[n] is garbage but
-                 * its value will never be used.
-                 */
-            } while (--n);
-#endif
+            slide_hash(s);
             more += wsize;
         }
-        if (s->strm->avail_in == 0) return;
+        if (s->strm->avail_in == 0) break;
 
         /* If there was no sliding:
          *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
@@ -1341,99 +1532,285 @@ local void fill_window(s)
         s->lookahead += n;
 
         /* Initialize the hash value now that we have some input: */
-        if (s->lookahead >= MIN_MATCH) {
-            s->ins_h = s->window[s->strstart];
-            UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
+        if (s->lookahead + s->insert >= MIN_MATCH) {
+            uInt str = s->strstart - s->insert;
+            s->ins_h = s->window[str];
+            UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
 #if MIN_MATCH != 3
             Call UPDATE_HASH() MIN_MATCH-3 more times
 #endif
+            while (s->insert) {
+                UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
+#ifndef FASTEST
+                s->prev[str & s->w_mask] = s->head[s->ins_h];
+#endif
+                s->head[s->ins_h] = (Pos)str;
+                str++;
+                s->insert--;
+                if (s->lookahead + s->insert < MIN_MATCH)
+                    break;
+            }
         }
         /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
          * but this is not important since only literal bytes will be emitted.
          */
 
     } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
+
+    /* If the WIN_INIT bytes after the end of the current data have never been
+     * written, then zero those bytes in order to avoid memory check reports of
+     * the use of uninitialized (or uninitialised as Julian writes) bytes by
+     * the longest match routines.  Update the high water mark for the next
+     * time through here.  WIN_INIT is set to MAX_MATCH since the longest match
+     * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
+     */
+    if (s->high_water < s->window_size) {
+        ulg curr = s->strstart + (ulg)(s->lookahead);
+        ulg init;
+
+        if (s->high_water < curr) {
+            /* Previous high water mark below current data -- zero WIN_INIT
+             * bytes or up to end of window, whichever is less.
+             */
+            init = s->window_size - curr;
+            if (init > WIN_INIT)
+                init = WIN_INIT;
+            zmemzero(s->window + curr, (unsigned)init);
+            s->high_water = curr + init;
+        }
+        else if (s->high_water < (ulg)curr + WIN_INIT) {
+            /* High water mark at or above current data, but below current data
+             * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
+             * to end of window, whichever is less.
+             */
+            init = (ulg)curr + WIN_INIT - s->high_water;
+            if (init > s->window_size - s->high_water)
+                init = s->window_size - s->high_water;
+            zmemzero(s->window + s->high_water, (unsigned)init);
+            s->high_water += init;
+        }
+    }
+
+    Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
+           "not enough room for search");
 }
 
 /* ===========================================================================
  * Flush the current block, with given end-of-file flag.
  * IN assertion: strstart is set to the end of the current match.
  */
-#define FLUSH_BLOCK_ONLY(s, eof) { \
+#define FLUSH_BLOCK_ONLY(s, last) { \
    _tr_flush_block(s, (s->block_start >= 0L ? \
                    (charf *)&s->window[(unsigned)s->block_start] : \
                    (charf *)Z_NULL), \
                 (ulg)((long)s->strstart - s->block_start), \
-                (eof)); \
+                (last)); \
    s->block_start = s->strstart; \
    flush_pending(s->strm); \
    Tracev((stderr,"[FLUSH]")); \
 }
 
 /* Same but force premature exit if necessary. */
-#define FLUSH_BLOCK(s, eof) { \
-   FLUSH_BLOCK_ONLY(s, eof); \
-   if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
+#define FLUSH_BLOCK(s, last) { \
+   FLUSH_BLOCK_ONLY(s, last); \
+   if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
 }
 
+/* Maximum stored block length in deflate format (not including header). */
+#define MAX_STORED 65535
+
+#ifndef MIN
+/* Minimum of a and b. */
+#define MIN(a, b) ((a) > (b) ? (b) : (a))
+#endif
+
 /* ===========================================================================
  * Copy without compression as much as possible from the input stream, return
  * the current block state.
- * This function does not insert new strings in the dictionary since
- * uncompressible data is probably not useful. This function is used
- * only for the level=0 compression option.
- * NOTE: this function should be optimized to avoid extra copying from
- * window to pending_buf.
+ *
+ * In case deflateParams() is used to later switch to a non-zero compression
+ * level, s->matches (otherwise unused when storing) keeps track of the number
+ * of hash table slides to perform. If s->matches is 1, then one hash table
+ * slide will be done when switching. If s->matches is 2, the maximum value
+ * allowed here, then the hash table will be cleared, since two or more slides
+ * is the same as a clear.
+ *
+ * deflate_stored() is written to minimize the number of times an input byte is
+ * copied. It is most efficient with large input and output buffers, which
+ * maximizes the opportunites to have a single copy from next_in to next_out.
  */
 local block_state deflate_stored(s, flush)
     deflate_state *s;
     int flush;
 {
-    /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
-     * to pending_buf_size, and each stored block has a 5 byte header:
+    /* Smallest worthy block size when not flushing or finishing. By default
+     * this is 32K. This can be as small as 507 bytes for memLevel == 1. For
+     * large input and output buffers, the stored block size will be larger.
      */
-    ulg max_block_size = 0xffff;
-    ulg max_start;
+    unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);
 
-    if (max_block_size > s->pending_buf_size - 5) {
-        max_block_size = s->pending_buf_size - 5;
-    }
-
-    /* Copy as much as possible from input to output: */
-    for (;;) {
-        /* Fill the window as much as possible: */
-        if (s->lookahead <= 1) {
-
-            Assert(s->strstart < s->w_size+MAX_DIST(s) ||
-                   s->block_start >= (long)s->w_size, "slide too late");
+    /* Copy as many min_block or larger stored blocks directly to next_out as
+     * possible. If flushing, copy the remaining available input to next_out as
+     * stored blocks, if there is enough space.
+     */
+    unsigned len, left, have, last = 0;
+    unsigned used = s->strm->avail_in;
+    do {
+        /* Set len to the maximum size block that we can copy directly with the
+         * available input data and output space. Set left to how much of that
+         * would be copied from what's left in the window.
+         */
+        len = MAX_STORED;       /* maximum deflate stored block length */
+        have = (s->bi_valid + 42) >> 3;         /* number of header bytes */
+        if (s->strm->avail_out < have)          /* need room for header */
+            break;
+            /* maximum stored block length that will fit in avail_out: */
+        have = s->strm->avail_out - have;
+        left = s->strstart - s->block_start;    /* bytes left in window */
+        if (len > (ulg)left + s->strm->avail_in)
+            len = left + s->strm->avail_in;     /* limit len to the input */
+        if (len > have)
+            len = have;                         /* limit len to the output */
+
+        /* If the stored block would be less than min_block in length, or if
+         * unable to copy all of the available input when flushing, then try
+         * copying to the window and the pending buffer instead. Also don't
+         * write an empty block when flushing -- deflate() does that.
+         */
+        if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
+                                flush == Z_NO_FLUSH ||
+                                len != left + s->strm->avail_in))
+            break;
 
-            fill_window(s);
-            if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
+        /* Make a dummy stored block in pending to get the header bytes,
+         * including any pending bits. This also updates the debugging counts.
+         */
+        last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
+        _tr_stored_block(s, (char *)0, 0L, last);
+
+        /* Replace the lengths in the dummy stored block with len. */
+        s->pending_buf[s->pending - 4] = len;
+        s->pending_buf[s->pending - 3] = len >> 8;
+        s->pending_buf[s->pending - 2] = ~len;
+        s->pending_buf[s->pending - 1] = ~len >> 8;
+
+        /* Write the stored block header bytes. */
+        flush_pending(s->strm);
+
+#ifdef ZLIB_DEBUG
+        /* Update debugging counts for the data about to be copied. */
+        s->compressed_len += len << 3;
+        s->bits_sent += len << 3;
+#endif
 
-            if (s->lookahead == 0) break; /* flush the current block */
+        /* Copy uncompressed bytes from the window to next_out. */
+        if (left) {
+            if (left > len)
+                left = len;
+            zmemcpy(s->strm->next_out, s->window + s->block_start, left);
+            s->strm->next_out += left;
+            s->strm->avail_out -= left;
+            s->strm->total_out += left;
+            s->block_start += left;
+            len -= left;
         }
-        Assert(s->block_start >= 0L, "block gone");
-
-        s->strstart += s->lookahead;
-        s->lookahead = 0;
-
-        /* Emit a stored block if pending_buf will be full: */
-        max_start = s->block_start + max_block_size;
-        if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
-            /* strstart == 0 is possible when wraparound on 16-bit machine */
-            s->lookahead = (uInt)(s->strstart - max_start);
-            s->strstart = (uInt)max_start;
-            FLUSH_BLOCK(s, 0);
+
+        /* Copy uncompressed bytes directly from next_in to next_out, updating
+         * the check value.
+         */
+        if (len) {
+            read_buf(s->strm, s->strm->next_out, len);
+            s->strm->next_out += len;
+            s->strm->avail_out -= len;
+            s->strm->total_out += len;
         }
-        /* Flush if we may have to slide, otherwise block_start may become
-         * negative and the data will be gone:
+    } while (last == 0);
+
+    /* Update the sliding window with the last s->w_size bytes of the copied
+     * data, or append all of the copied data to the existing window if less
+     * than s->w_size bytes were copied. Also update the number of bytes to
+     * insert in the hash tables, in the event that deflateParams() switches to
+     * a non-zero compression level.
+     */
+    used -= s->strm->avail_in;      /* number of input bytes directly copied */
+    if (used) {
+        /* If any input was used, then no unused input remains in the window,
+         * therefore s->block_start == s->strstart.
          */
-        if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
-            FLUSH_BLOCK(s, 0);
+        if (used >= s->w_size) {    /* supplant the previous history */
+            s->matches = 2;         /* clear hash */
+            zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
+            s->strstart = s->w_size;
         }
+        else {
+            if (s->window_size - s->strstart <= used) {
+                /* Slide the window down. */
+                s->strstart -= s->w_size;
+                zmemcpy(s->window, s->window + s->w_size, s->strstart);
+                if (s->matches < 2)
+                    s->matches++;   /* add a pending slide_hash() */
+            }
+            zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
+            s->strstart += used;
+        }
+        s->block_start = s->strstart;
+        s->insert += MIN(used, s->w_size - s->insert);
+    }
+    if (s->high_water < s->strstart)
+        s->high_water = s->strstart;
+
+    /* If the last block was written to next_out, then done. */
+    if (last)
+        return finish_done;
+
+    /* If flushing and all input has been consumed, then done. */
+    if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
+        s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
+        return block_done;
+
+    /* Fill the window with any remaining input. */
+    have = s->window_size - s->strstart - 1;
+    if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
+        /* Slide the window down. */
+        s->block_start -= s->w_size;
+        s->strstart -= s->w_size;
+        zmemcpy(s->window, s->window + s->w_size, s->strstart);
+        if (s->matches < 2)
+            s->matches++;           /* add a pending slide_hash() */
+        have += s->w_size;          /* more space now */
+    }
+    if (have > s->strm->avail_in)
+        have = s->strm->avail_in;
+    if (have) {
+        read_buf(s->strm, s->window + s->strstart, have);
+        s->strstart += have;
+    }
+    if (s->high_water < s->strstart)
+        s->high_water = s->strstart;
+
+    /* There was not enough avail_out to write a complete worthy or flushed
+     * stored block to next_out. Write a stored block to pending instead, if we
+     * have enough input for a worthy block, or if flushing and there is enough
+     * room for the remaining input as a stored block in the pending buffer.
+     */
+    have = (s->bi_valid + 42) >> 3;         /* number of header bytes */
+        /* maximum stored block length that will fit in pending: */
+    have = MIN(s->pending_buf_size - have, MAX_STORED);
+    min_block = MIN(have, s->w_size);
+    left = s->strstart - s->block_start;
+    if (left >= min_block ||
+        ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
+         s->strm->avail_in == 0 && left <= have)) {
+        len = MIN(left, have);
+        last = flush == Z_FINISH && s->strm->avail_in == 0 &&
+               len == left ? 1 : 0;
+        _tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
+        s->block_start += len;
+        flush_pending(s->strm);
     }
-    FLUSH_BLOCK(s, flush == Z_FINISH);
-    return flush == Z_FINISH ? finish_done : block_done;
+
+    /* We've done all we can with the available input and output. */
+    return last ? finish_started : need_more;
 }
 
 /* ===========================================================================
@@ -1447,7 +1824,7 @@ local block_state deflate_fast(s, flush)
     deflate_state *s;
     int flush;
 {
-    IPos hash_head = NIL; /* head of the hash chain */
+    IPos hash_head;       /* head of the hash chain */
     int bflush;           /* set if current block must be flushed */
 
     for (;;) {
@@ -1467,6 +1844,7 @@ local block_state deflate_fast(s, flush)
         /* Insert the string window[strstart .. strstart+2] in the
          * dictionary, and set hash_head to the head of the hash chain:
          */
+        hash_head = NIL;
         if (s->lookahead >= MIN_MATCH) {
             INSERT_STRING(s, s->strstart, hash_head);
         }
@@ -1479,19 +1857,8 @@ local block_state deflate_fast(s, flush)
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
-#ifdef FASTEST
-            if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
-                (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
-                s->match_length = longest_match_fast (s, hash_head);
-            }
-#else
-            if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
-                s->match_length = longest_match (s, hash_head);
-            } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
-                s->match_length = longest_match_fast (s, hash_head);
-            }
-#endif
-            /* longest_match() or longest_match_fast() sets match_start */
+            s->match_length = longest_match (s, hash_head);
+            /* longest_match() sets match_start */
         }
         if (s->match_length >= MIN_MATCH) {
             check_match(s, s->strstart, s->match_start, s->match_length);
@@ -1539,8 +1906,14 @@ local block_state deflate_fast(s, flush)
         }
         if (bflush) FLUSH_BLOCK(s, 0);
     }
-    FLUSH_BLOCK(s, flush == Z_FINISH);
-    return flush == Z_FINISH ? finish_done : block_done;
+    s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
+    if (flush == Z_FINISH) {
+        FLUSH_BLOCK(s, 1);
+        return finish_done;
+    }
+    if (s->last_lit)
+        FLUSH_BLOCK(s, 0);
+    return block_done;
 }
 
 #ifndef FASTEST
@@ -1553,7 +1926,7 @@ local block_state deflate_slow(s, flush)
     deflate_state *s;
     int flush;
 {
-    IPos hash_head = NIL;    /* head of hash chain */
+    IPos hash_head;          /* head of hash chain */
     int bflush;              /* set if current block must be flushed */
 
     /* Process the input block. */
@@ -1574,6 +1947,7 @@ local block_state deflate_slow(s, flush)
         /* Insert the string window[strstart .. strstart+2] in the
          * dictionary, and set hash_head to the head of the hash chain:
          */
+        hash_head = NIL;
         if (s->lookahead >= MIN_MATCH) {
             INSERT_STRING(s, s->strstart, hash_head);
         }
@@ -1589,12 +1963,8 @@ local block_state deflate_slow(s, flush)
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
-            if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
-                s->match_length = longest_match (s, hash_head);
-            } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
-                s->match_length = longest_match_fast (s, hash_head);
-            }
-            /* longest_match() or longest_match_fast() sets match_start */
+            s->match_length = longest_match (s, hash_head);
+            /* longest_match() sets match_start */
 
             if (s->match_length <= 5 && (s->strategy == Z_FILTERED
 #if TOO_FAR <= 32767
@@ -1667,12 +2037,17 @@ local block_state deflate_slow(s, flush)
         _tr_tally_lit(s, s->window[s->strstart-1], bflush);
         s->match_available = 0;
     }
-    FLUSH_BLOCK(s, flush == Z_FINISH);
-    return flush == Z_FINISH ? finish_done : block_done;
+    s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
+    if (flush == Z_FINISH) {
+        FLUSH_BLOCK(s, 1);
+        return finish_done;
+    }
+    if (s->last_lit)
+        FLUSH_BLOCK(s, 0);
+    return block_done;
 }
 #endif /* FASTEST */
 
-#if 0
 /* ===========================================================================
  * For Z_RLE, simply look for runs of bytes, generate matches only of distance
  * one.  Do not maintain a hash table.  (It will be regenerated if this run of
@@ -1682,43 +2057,52 @@ local block_state deflate_rle(s, flush)
     deflate_state *s;
     int flush;
 {
-    int bflush;         /* set if current block must be flushed */
-    uInt run;           /* length of run */
-    uInt max;           /* maximum length of run */
-    uInt prev;          /* byte at distance one to match */
-    Bytef *scan;        /* scan for end of run */
+    int bflush;             /* set if current block must be flushed */
+    uInt prev;              /* byte at distance one to match */
+    Bytef *scan, *strend;   /* scan goes up to strend for length of run */
 
     for (;;) {
         /* Make sure that we always have enough lookahead, except
          * at the end of the input file. We need MAX_MATCH bytes
-         * for the longest encodable run.
+         * for the longest run, plus one for the unrolled loop.
          */
-        if (s->lookahead < MAX_MATCH) {
+        if (s->lookahead <= MAX_MATCH) {
             fill_window(s);
-            if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
+            if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
                 return need_more;
             }
             if (s->lookahead == 0) break; /* flush the current block */
         }
 
         /* See how many times the previous byte repeats */
-        run = 0;
-        if (s->strstart > 0) {      /* if there is a previous byte, that is */
-            max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
+        s->match_length = 0;
+        if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
             scan = s->window + s->strstart - 1;
-            prev = *scan++;
-            do {
-                if (*scan++ != prev)
-                    break;
-            } while (++run < max);
+            prev = *scan;
+            if (prev == *++scan && prev == *++scan && prev == *++scan) {
+                strend = s->window + s->strstart + MAX_MATCH;
+                do {
+                } while (prev == *++scan && prev == *++scan &&
+                         prev == *++scan && prev == *++scan &&
+                         prev == *++scan && prev == *++scan &&
+                         prev == *++scan && prev == *++scan &&
+                         scan < strend);
+                s->match_length = MAX_MATCH - (uInt)(strend - scan);
+                if (s->match_length > s->lookahead)
+                    s->match_length = s->lookahead;
+            }
+            Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
         }
 
         /* Emit match if have run of MIN_MATCH or longer, else emit literal */
-        if (run >= MIN_MATCH) {
-            check_match(s, s->strstart, s->strstart - 1, run);
-            _tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
-            s->lookahead -= run;
-            s->strstart += run;
+        if (s->match_length >= MIN_MATCH) {
+            check_match(s, s->strstart, s->strstart - 1, s->match_length);
+
+            _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
+
+            s->lookahead -= s->match_length;
+            s->strstart += s->match_length;
+            s->match_length = 0;
         } else {
             /* No match, output a literal byte */
             Tracevv((stderr,"%c", s->window[s->strstart]));
@@ -1728,7 +2112,51 @@ local block_state deflate_rle(s, flush)
         }
         if (bflush) FLUSH_BLOCK(s, 0);
     }
-    FLUSH_BLOCK(s, flush == Z_FINISH);
-    return flush == Z_FINISH ? finish_done : block_done;
+    s->insert = 0;
+    if (flush == Z_FINISH) {
+        FLUSH_BLOCK(s, 1);
+        return finish_done;
+    }
+    if (s->last_lit)
+        FLUSH_BLOCK(s, 0);
+    return block_done;
+}
+
+/* ===========================================================================
+ * For Z_HUFFMAN_ONLY, do not look for matches.  Do not maintain a hash table.
+ * (It will be regenerated if this run of deflate switches away from Huffman.)
+ */
+local block_state deflate_huff(s, flush)
+    deflate_state *s;
+    int flush;
+{
+    int bflush;             /* set if current block must be flushed */
+
+    for (;;) {
+        /* Make sure that we have a literal to write. */
+        if (s->lookahead == 0) {
+            fill_window(s);
+            if (s->lookahead == 0) {
+                if (flush == Z_NO_FLUSH)
+                    return need_more;
+                break;      /* flush the current block */
+            }
+        }
+
+        /* Output a literal byte */
+        s->match_length = 0;
+        Tracevv((stderr,"%c", s->window[s->strstart]));
+        _tr_tally_lit (s, s->window[s->strstart], bflush);
+        s->lookahead--;
+        s->strstart++;
+        if (bflush) FLUSH_BLOCK(s, 0);
+    }
+    s->insert = 0;
+    if (flush == Z_FINISH) {
+        FLUSH_BLOCK(s, 1);
+        return finish_done;
+    }
+    if (s->last_lit)
+        FLUSH_BLOCK(s, 0);
+    return block_done;
 }
-#endif
diff --git a/sys/lib/libz/deflate.h b/sys/lib/libz/deflate.h
index bb22284f477..2a01547b94e 100644
--- a/sys/lib/libz/deflate.h
+++ b/sys/lib/libz/deflate.h
@@ -1,6 +1,5 @@
-/*	$OpenBSD: deflate.h,v 1.2 2011/07/16 07:25:29 jsing Exp $	*/
 /* deflate.h -- internal compression state
- * Copyright (C) 1995-2004 Jean-loup Gailly
+ * Copyright (C) 1995-2016 Jean-loup Gailly
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,7 +8,6 @@
    subject to change. Applications should only use zlib.h.
  */
 
-
 #ifndef DEFLATE_H
 #define DEFLATE_H
 
@@ -48,13 +46,19 @@
 #define MAX_BITS 15
 /* All codes must not exceed MAX_BITS bits */
 
-#define INIT_STATE    42
-#define EXTRA_STATE   69
-#define NAME_STATE    73
-#define COMMENT_STATE 91
-#define HCRC_STATE   103
-#define BUSY_STATE   113
-#define FINISH_STATE 666
+#define Buf_size 16
+/* size of bit buffer in bi_buf */
+
+#define INIT_STATE    42    /* zlib header -> BUSY_STATE */
+#ifdef GZIP
+#  define GZIP_STATE  57    /* gzip header -> BUSY_STATE | EXTRA_STATE */
+#endif
+#define EXTRA_STATE   69    /* gzip extra block -> NAME_STATE */
+#define NAME_STATE    73    /* gzip file name -> COMMENT_STATE */
+#define COMMENT_STATE 91    /* gzip comment -> HCRC_STATE */
+#define HCRC_STATE   103    /* gzip header CRC -> BUSY_STATE */
+#define BUSY_STATE   113    /* deflate -> FINISH_STATE */
+#define FINISH_STATE 666    /* stream complete */
 /* Stream status */
 
 
@@ -80,7 +84,7 @@ typedef struct static_tree_desc_s  static_tree_desc;
 typedef struct tree_desc_s {
     ct_data *dyn_tree;           /* the dynamic tree */
     int     max_code;            /* largest code with non zero frequency */
-    static_tree_desc *stat_desc; /* the corresponding static tree */
+    const static_tree_desc *stat_desc;  /* the corresponding static tree */
 } FAR tree_desc;
 
 typedef ush Pos;
@@ -97,11 +101,11 @@ typedef struct internal_state {
     Bytef *pending_buf;  /* output still pending */
     ulg   pending_buf_size; /* size of pending_buf */
     Bytef *pending_out;  /* next pending byte to output to the stream */
-    uInt   pending;      /* nb of bytes in the pending buffer */
+    ulg   pending;       /* nb of bytes in the pending buffer */
     int   wrap;          /* bit 0 true for zlib, bit 1 true for gzip */
     gz_headerp  gzhead;  /* gzip header information to write */
-    uInt   gzindex;      /* where in extra, name, or comment */
-    Byte  method;        /* STORED (for zip only) or DEFLATED */
+    ulg   gzindex;       /* where in extra, name, or comment */
+    Byte  method;        /* can only be DEFLATED */
     int   last_flush;    /* value of flush param for previous deflate call */
 
                 /* used by deflate.c: */
@@ -244,9 +248,9 @@ typedef struct internal_state {
     ulg opt_len;        /* bit length of current block with optimal trees */
     ulg static_len;     /* bit length of current block with static trees */
     uInt matches;       /* number of string matches in current block */
-    int last_eob_len;   /* bit length of EOB code for last block */
+    uInt insert;        /* bytes at end of window left to insert */
 
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
     ulg compressed_len; /* total bit length of compressed file mod 2^32 */
     ulg bits_sent;      /* bit length of compressed data sent mod 2^32 */
 #endif
@@ -260,12 +264,19 @@ typedef struct internal_state {
      * are always zero.
      */
 
+    ulg high_water;
+    /* High water mark offset in window for initialized bytes -- bytes above
+     * this are set to zero in order to avoid memory check warnings when
+     * longest match routines access bytes past the input.  This is then
+     * updated to the new high water mark.
+     */
+
 } FAR deflate_state;
 
 /* Output a byte on the stream.
  * IN assertion: there is enough room in pending_buf.
  */
-#define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
+#define put_byte(s, c) {s->pending_buf[s->pending++] = (Bytef)(c);}
 
 
 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
@@ -278,14 +289,19 @@ typedef struct internal_state {
  * distances are limited to MAX_DIST instead of WSIZE.
  */
 
+#define WIN_INIT MAX_MATCH
+/* Number of bytes after end of data in window to initialize in order to avoid
+   memory checker errors from longest match routines */
+
         /* in trees.c */
-void _tr_init         OF((deflate_state *s));
-int  _tr_tally        OF((deflate_state *s, unsigned dist, unsigned lc));
-void _tr_flush_block  OF((deflate_state *s, charf *buf, ulg stored_len,
-                          int eof));
-void _tr_align        OF((deflate_state *s));
-void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
-                          int eof));
+void ZLIB_INTERNAL _tr_init OF((deflate_state *s));
+int ZLIB_INTERNAL _tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
+void ZLIB_INTERNAL _tr_flush_block OF((deflate_state *s, charf *buf,
+                        ulg stored_len, int last));
+void ZLIB_INTERNAL _tr_flush_bits OF((deflate_state *s));
+void ZLIB_INTERNAL _tr_align OF((deflate_state *s));
+void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
+                        ulg stored_len, int last));
 
 #define d_code(dist) \
    ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
@@ -294,15 +310,15 @@ void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
  * used.
  */
 
-#ifndef DEBUG_LIBZ
+#ifndef ZLIB_DEBUG
 /* Inline versions of _tr_tally for speed: */
 
 #if defined(GEN_TREES_H) || !defined(STDC)
-  extern uch _length_code[];
-  extern uch _dist_code[];
+  extern uch ZLIB_INTERNAL _length_code[];
+  extern uch ZLIB_INTERNAL _dist_code[];
 #else
-  extern const uch _length_code[];
-  extern const uch _dist_code[];
+  extern const uch ZLIB_INTERNAL _length_code[];
+  extern const uch ZLIB_INTERNAL _dist_code[];
 #endif
 
 # define _tr_tally_lit(s, c, flush) \
@@ -313,8 +329,8 @@ void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
     flush = (s->last_lit == s->lit_bufsize-1); \
    }
 # define _tr_tally_dist(s, distance, length, flush) \
-  { uch len = (length); \
-    ush dist = (distance); \
+  { uch len = (uch)(length); \
+    ush dist = (ush)(distance); \
     s->d_buf[s->last_lit] = dist; \
     s->l_buf[s->last_lit++] = len; \
     dist--; \
diff --git a/sys/lib/libz/infback.c b/sys/lib/libz/infback.c
index e9803588915..037ecac581c 100644
--- a/sys/lib/libz/infback.c
+++ b/sys/lib/libz/infback.c
@@ -1,5 +1,6 @@
+/*	$OpenBSD: infback.c,v 1.7 2021/07/04 14:24:49 tb Exp $ */
 /* infback.c -- inflate using a call-back interface
- * Copyright (C) 1995-2005 Mark Adler
+ * Copyright (C) 1995-2016 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -42,20 +43,29 @@ int stream_size;
         return Z_STREAM_ERROR;
     strm->msg = Z_NULL;                 /* in case we return an error */
     if (strm->zalloc == (alloc_func)0) {
+#ifdef Z_SOLO
+        return Z_STREAM_ERROR;
+#else
         strm->zalloc = zcalloc;
         strm->opaque = (voidpf)0;
+#endif
     }
-    if (strm->zfree == (free_func)0) strm->zfree = zcfree;
+    if (strm->zfree == (free_func)0)
+#ifdef Z_SOLO
+        return Z_STREAM_ERROR;
+#else
+    strm->zfree = zcfree;
+#endif
     state = (struct inflate_state FAR *)ZALLOC(strm, 1,
                                                sizeof(struct inflate_state));
     if (state == Z_NULL) return Z_MEM_ERROR;
     Tracev((stderr, "inflate: allocated\n"));
     strm->state = (struct internal_state FAR *)state;
     state->dmax = 32768U;
-    state->wbits = windowBits;
+    state->wbits = (uInt)windowBits;
     state->wsize = 1U << windowBits;
     state->window = window;
-    state->write = 0;
+    state->wnext = 0;
     state->whave = 0;
     return Z_OK;
 }
@@ -253,7 +263,7 @@ void FAR *out_desc;
     unsigned bits;              /* bits in bit buffer */
     unsigned copy;              /* number of stored or match bytes to copy */
     unsigned char FAR *from;    /* where to copy match bytes from */
-    code this;                  /* current decoding table entry */
+    code here;                  /* current decoding table entry */
     code last;                  /* parent table entry */
     unsigned len;               /* length to copy for repeats, bits to drop */
     int ret;                    /* return code */
@@ -308,8 +318,8 @@ void FAR *out_desc;
                 state->mode = TABLE;
                 break;
             case 3:
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid block type";
 #endif
@@ -323,8 +333,8 @@ void FAR *out_desc;
             BYTEBITS();                         /* go to byte boundary */
             NEEDBITS(32);
             if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid stored block lengths";
 #endif
@@ -365,8 +375,8 @@ void FAR *out_desc;
             DROPBITS(4);
 #ifndef PKZIP_BUG_WORKAROUND
             if (state->nlen > 286 || state->ndist > 30) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"too many length or distance symbols";
 #endif
@@ -391,7 +401,11 @@ void FAR *out_desc;
             ret = inflate_table(CODES, state->lens, 19, &(state->next),
                                 &(state->lenbits), state->work);
             if (ret) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
                 strm->msg = (char *)"invalid code lengths set";
+#endif
                 state->mode = BAD;
                 break;
             }
@@ -401,21 +415,24 @@ void FAR *out_desc;
             state->have = 0;
             while (state->have < state->nlen + state->ndist) {
                 for (;;) {
-                    this = state->lencode[BITS(state->lenbits)];
-                    if ((unsigned)(this.bits) <= bits) break;
+                    here = state->lencode[BITS(state->lenbits)];
+                    if ((unsigned)(here.bits) <= bits) break;
                     PULLBYTE();
                 }
-                if (this.val < 16) {
-                    NEEDBITS(this.bits);
-                    DROPBITS(this.bits);
-                    state->lens[state->have++] = this.val;
+                if (here.val < 16) {
+                    DROPBITS(here.bits);
+                    state->lens[state->have++] = here.val;
                 }
                 else {
-                    if (this.val == 16) {
-                        NEEDBITS(this.bits + 2);
-                        DROPBITS(this.bits);
+                    if (here.val == 16) {
+                        NEEDBITS(here.bits + 2);
+                        DROPBITS(here.bits);
                         if (state->have == 0) {
+#ifdef SMALL
+                            strm->msg = "error";
+#else
                             strm->msg = (char *)"invalid bit length repeat";
+#endif
                             state->mode = BAD;
                             break;
                         }
@@ -423,22 +440,26 @@ void FAR *out_desc;
                         copy = 3 + BITS(2);
                         DROPBITS(2);
                     }
-                    else if (this.val == 17) {
-                        NEEDBITS(this.bits + 3);
-                        DROPBITS(this.bits);
+                    else if (here.val == 17) {
+                        NEEDBITS(here.bits + 3);
+                        DROPBITS(here.bits);
                         len = 0;
                         copy = 3 + BITS(3);
                         DROPBITS(3);
                     }
                     else {
-                        NEEDBITS(this.bits + 7);
-                        DROPBITS(this.bits);
+                        NEEDBITS(here.bits + 7);
+                        DROPBITS(here.bits);
                         len = 0;
                         copy = 11 + BITS(7);
                         DROPBITS(7);
                     }
                     if (state->have + copy > state->nlen + state->ndist) {
+#ifdef SMALL
+                        strm->msg = "error";
+#else
                         strm->msg = (char *)"invalid bit length repeat";
+#endif
                         state->mode = BAD;
                         break;
                     }
@@ -450,14 +471,31 @@ void FAR *out_desc;
             /* handle error breaks in while */
             if (state->mode == BAD) break;
 
-            /* build code tables */
+            /* check for end-of-block code (better have one) */
+            if (state->lens[256] == 0) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
+                strm->msg = (char *)"invalid code -- missing end-of-block";
+#endif
+                state->mode = BAD;
+                break;
+            }
+
+            /* build code tables -- note: do not change the lenbits or distbits
+               values here (9 and 6) without reading the comments in inftrees.h
+               concerning the ENOUGH constants, which depend on those values */
             state->next = state->codes;
             state->lencode = (code const FAR *)(state->next);
             state->lenbits = 9;
             ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
                                 &(state->lenbits), state->work);
             if (ret) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
                 strm->msg = (char *)"invalid literal/lengths set";
+#endif
                 state->mode = BAD;
                 break;
             }
@@ -466,7 +504,11 @@ void FAR *out_desc;
             ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
                             &(state->next), &(state->distbits), state->work);
             if (ret) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
                 strm->msg = (char *)"invalid distances set";
+#endif
                 state->mode = BAD;
                 break;
             }
@@ -488,28 +530,28 @@ void FAR *out_desc;
 
             /* get a literal, length, or end-of-block code */
             for (;;) {
-                this = state->lencode[BITS(state->lenbits)];
-                if ((unsigned)(this.bits) <= bits) break;
+                here = state->lencode[BITS(state->lenbits)];
+                if ((unsigned)(here.bits) <= bits) break;
                 PULLBYTE();
             }
-            if (this.op && (this.op & 0xf0) == 0) {
-                last = this;
+            if (here.op && (here.op & 0xf0) == 0) {
+                last = here;
                 for (;;) {
-                    this = state->lencode[last.val +
+                    here = state->lencode[last.val +
                             (BITS(last.bits + last.op) >> last.bits)];
-                    if ((unsigned)(last.bits + this.bits) <= bits) break;
+                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                     PULLBYTE();
                 }
                 DROPBITS(last.bits);
             }
-            DROPBITS(this.bits);
-            state->length = (unsigned)this.val;
+            DROPBITS(here.bits);
+            state->length = (unsigned)here.val;
 
             /* process literal */
-            if (this.op == 0) {
-                Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
+            if (here.op == 0) {
+                Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
                         "inflate:         literal '%c'\n" :
-                        "inflate:         literal 0x%02x\n", this.val));
+                        "inflate:         literal 0x%02x\n", here.val));
                 ROOM();
                 *put++ = (unsigned char)(state->length);
                 left--;
@@ -518,21 +560,25 @@ void FAR *out_desc;
             }
 
             /* process end of block */
-            if (this.op & 32) {
+            if (here.op & 32) {
                 Tracevv((stderr, "inflate:         end of block\n"));
                 state->mode = TYPE;
                 break;
             }
 
             /* invalid code */
-            if (this.op & 64) {
+            if (here.op & 64) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
                 strm->msg = (char *)"invalid literal/length code";
+#endif
                 state->mode = BAD;
                 break;
             }
 
             /* length code -- get extra bits, if any */
-            state->extra = (unsigned)(this.op) & 15;
+            state->extra = (unsigned)(here.op) & 15;
             if (state->extra != 0) {
                 NEEDBITS(state->extra);
                 state->length += BITS(state->extra);
@@ -542,30 +588,34 @@ void FAR *out_desc;
 
             /* get distance code */
             for (;;) {
-                this = state->distcode[BITS(state->distbits)];
-                if ((unsigned)(this.bits) <= bits) break;
+                here = state->distcode[BITS(state->distbits)];
+                if ((unsigned)(here.bits) <= bits) break;
                 PULLBYTE();
             }
-            if ((this.op & 0xf0) == 0) {
-                last = this;
+            if ((here.op & 0xf0) == 0) {
+                last = here;
                 for (;;) {
-                    this = state->distcode[last.val +
+                    here = state->distcode[last.val +
                             (BITS(last.bits + last.op) >> last.bits)];
-                    if ((unsigned)(last.bits + this.bits) <= bits) break;
+                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                     PULLBYTE();
                 }
                 DROPBITS(last.bits);
             }
-            DROPBITS(this.bits);
-            if (this.op & 64) {
+            DROPBITS(here.bits);
+            if (here.op & 64) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
                 strm->msg = (char *)"invalid distance code";
+#endif
                 state->mode = BAD;
                 break;
             }
-            state->offset = (unsigned)this.val;
+            state->offset = (unsigned)here.val;
 
             /* get distance extra bits, if any */
-            state->extra = (unsigned)(this.op) & 15;
+            state->extra = (unsigned)(here.op) & 15;
             if (state->extra != 0) {
                 NEEDBITS(state->extra);
                 state->offset += BITS(state->extra);
@@ -573,7 +623,11 @@ void FAR *out_desc;
             }
             if (state->offset > state->wsize - (state->whave < state->wsize ?
                                                 left : 0)) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
                 strm->msg = (char *)"invalid distance too far back";
+#endif
                 state->mode = BAD;
                 break;
             }
diff --git a/sys/lib/libz/inffast.c b/sys/lib/libz/inffast.c
index 9e7b53f715c..4902dacdc1a 100644
--- a/sys/lib/libz/inffast.c
+++ b/sys/lib/libz/inffast.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: inffast.c,v 1.12 2019/06/01 11:39:57 jca Exp $	*/
+/*	$OpenBSD: inffast.c,v 1.13 2021/07/04 14:24:49 tb Exp $ */
 /* inffast.c -- fast decoding
- * Copyright (C) 1995-2004 Mark Adler
+ * Copyright (C) 1995-2017 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,26 +9,9 @@
 #include "inflate.h"
 #include "inffast.h"
 
-#ifndef ASMINF
-
-/* Allow machine dependent optimization for post-increment or pre-increment.
-   Based on testing to date,
-   Pre-increment preferred for:
-   - PowerPC G3 (Adler)
-   - MIPS R5000 (Randers-Pehrson)
-   Post-increment preferred for:
-   - none
-   No measurable difference:
-   - Pentium III (Anderson)
-   - M68060 (Nikl)
- */
-#ifdef POSTINC
-#  define OFF 0
-#  define PUP(a) *(a)++
+#ifdef ASMINF
+#  pragma message("Assembler code may have bugs -- use at your own risk")
 #else
-#  define OFF 1
-#  define PUP(a) *++(a)
-#endif
 
 /*
    Decode literal, length, and distance codes and write out the resulting
@@ -65,13 +48,13 @@
       requires strm->avail_out >= 258 for each loop to avoid checking for
       output space.
  */
-void inflate_fast(strm, start)
+void ZLIB_INTERNAL inflate_fast(strm, start)
 z_streamp strm;
 unsigned start;         /* inflate()'s starting value for strm->avail_out */
 {
     struct inflate_state FAR *state;
     z_const unsigned char FAR *in;      /* local strm->next_in */
-    z_const unsigned char FAR *last;    /* while in < last, enough input available */
+    z_const unsigned char FAR *last;    /* have enough input while in < last */
     unsigned char FAR *out;     /* local strm->next_out */
     unsigned char FAR *beg;     /* inflate()'s initial strm->next_out */
     unsigned char FAR *end;     /* while out < end, enough space available */
@@ -80,7 +63,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
 #endif
     unsigned wsize;             /* window size or zero if not using window */
     unsigned whave;             /* valid bytes in the window */
-    unsigned write;             /* window write index */
+    unsigned wnext;             /* window write index */
     unsigned char FAR *window;  /* allocated sliding window, if wsize != 0 */
     unsigned long hold;         /* local strm->hold */
     unsigned bits;              /* local strm->bits */
@@ -88,7 +71,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
     code const FAR *dcode;      /* local strm->distcode */
     unsigned lmask;             /* mask for first level of length codes */
     unsigned dmask;             /* mask for first level of distance codes */
-    code this;                  /* retrieved table entry */
+    code here;                  /* retrieved table entry */
     unsigned op;                /* code bits, operation, extra bits, or */
                                 /*  window position, window bytes to copy */
     unsigned len;               /* match length, unused bytes */
@@ -97,9 +80,9 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
 
     /* copy state to local variables */
     state = (struct inflate_state FAR *)strm->state;
-    in = strm->next_in - OFF;
+    in = strm->next_in;
     last = in + (strm->avail_in - 5);
-    out = strm->next_out - OFF;
+    out = strm->next_out;
     beg = out - (start - strm->avail_out);
     end = out + (strm->avail_out - 257);
 #ifdef INFLATE_STRICT
@@ -107,7 +90,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
 #endif
     wsize = state->wsize;
     whave = state->whave;
-    write = state->write;
+    wnext = state->wnext;
     window = state->window;
     hold = state->hold;
     bits = state->bits;
@@ -120,29 +103,29 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
        input data or output space */
     do {
         if (bits < 15) {
-            hold += (unsigned long)(PUP(in)) << bits;
+            hold += (unsigned long)(*in++) << bits;
             bits += 8;
-            hold += (unsigned long)(PUP(in)) << bits;
+            hold += (unsigned long)(*in++) << bits;
             bits += 8;
         }
-        this = lcode[hold & lmask];
+        here = lcode[hold & lmask];
       dolen:
-        op = (unsigned)(this.bits);
+        op = (unsigned)(here.bits);
         hold >>= op;
         bits -= op;
-        op = (unsigned)(this.op);
+        op = (unsigned)(here.op);
         if (op == 0) {                          /* literal */
-            Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
+            Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
                     "inflate:         literal '%c'\n" :
-                    "inflate:         literal 0x%02x\n", this.val));
-            PUP(out) = (unsigned char)(this.val);
+                    "inflate:         literal 0x%02x\n", here.val));
+            *out++ = (unsigned char)(here.val);
         }
         else if (op & 16) {                     /* length base */
-            len = (unsigned)(this.val);
+            len = (unsigned)(here.val);
             op &= 15;                           /* number of extra bits */
             if (op) {
                 if (bits < op) {
-                    hold += (unsigned long)(PUP(in)) << bits;
+                    hold += (unsigned long)(*in++) << bits;
                     bits += 8;
                 }
                 len += (unsigned)hold & ((1U << op) - 1);
@@ -151,25 +134,25 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
             }
             Tracevv((stderr, "inflate:         length %u\n", len));
             if (bits < 15) {
-                hold += (unsigned long)(PUP(in)) << bits;
+                hold += (unsigned long)(*in++) << bits;
                 bits += 8;
-                hold += (unsigned long)(PUP(in)) << bits;
+                hold += (unsigned long)(*in++) << bits;
                 bits += 8;
             }
-            this = dcode[hold & dmask];
+            here = dcode[hold & dmask];
           dodist:
-            op = (unsigned)(this.bits);
+            op = (unsigned)(here.bits);
             hold >>= op;
             bits -= op;
-            op = (unsigned)(this.op);
+            op = (unsigned)(here.op);
             if (op & 16) {                      /* distance base */
-                dist = (unsigned)(this.val);
+                dist = (unsigned)(here.val);
                 op &= 15;                       /* number of extra bits */
                 if (bits < op) {
-                    hold += (unsigned long)(PUP(in)) << bits;
+                    hold += (unsigned long)(*in++) << bits;
                     bits += 8;
                     if (bits < op) {
-                        hold += (unsigned long)(PUP(in)) << bits;
+                        hold += (unsigned long)(*in++) << bits;
                         bits += 8;
                     }
                 }
@@ -188,88 +171,110 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
                 if (dist > op) {                /* see if copy from window */
                     op = dist - op;             /* distance back in window */
                     if (op > whave) {
-#ifdef SMALL  
-			strm->msg = "error";
+                        if (state->sane) {
+#ifdef SMALL
+                            strm->msg = "error";
 #else
-                        strm->msg = (char *)"invalid distance too far back";
+                            strm->msg =
+                                (char *)"invalid distance too far back";
+#endif
+                            state->mode = BAD;
+                            break;
+                        }
+#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
+                        if (len <= op - whave) {
+                            do {
+                                *out++ = 0;
+                            } while (--len);
+                            continue;
+                        }
+                        len -= op - whave;
+                        do {
+                            *out++ = 0;
+                        } while (--op > whave);
+                        if (op == 0) {
+                            from = out - dist;
+                            do {
+                                *out++ = *from++;
+                            } while (--len);
+                            continue;
+                        }
 #endif
-                        state->mode = BAD;
-                        break;
                     }
-                    from = window - OFF;
-                    if (write == 0) {           /* very common case */
+                    from = window;
+                    if (wnext == 0) {           /* very common case */
                         from += wsize - op;
                         if (op < len) {         /* some from window */
                             len -= op;
                             do {
-                                PUP(out) = PUP(from);
+                                *out++ = *from++;
                             } while (--op);
                             from = out - dist;  /* rest from output */
                         }
                     }
-                    else if (write < op) {      /* wrap around window */
-                        from += wsize + write - op;
-                        op -= write;
+                    else if (wnext < op) {      /* wrap around window */
+                        from += wsize + wnext - op;
+                        op -= wnext;
                         if (op < len) {         /* some from end of window */
                             len -= op;
                             do {
-                                PUP(out) = PUP(from);
+                                *out++ = *from++;
                             } while (--op);
-                            from = window - OFF;
-                            if (write < len) {  /* some from start of window */
-                                op = write;
+                            from = window;
+                            if (wnext < len) {  /* some from start of window */
+                                op = wnext;
                                 len -= op;
                                 do {
-                                    PUP(out) = PUP(from);
+                                    *out++ = *from++;
                                 } while (--op);
                                 from = out - dist;      /* rest from output */
                             }
                         }
                     }
                     else {                      /* contiguous in window */
-                        from += write - op;
+                        from += wnext - op;
                         if (op < len) {         /* some from window */
                             len -= op;
                             do {
-                                PUP(out) = PUP(from);
+                                *out++ = *from++;
                             } while (--op);
                             from = out - dist;  /* rest from output */
                         }
                     }
                     while (len > 2) {
-                        PUP(out) = PUP(from);
-                        PUP(out) = PUP(from);
-                        PUP(out) = PUP(from);
+                        *out++ = *from++;
+                        *out++ = *from++;
+                        *out++ = *from++;
                         len -= 3;
                     }
                     if (len) {
-                        PUP(out) = PUP(from);
+                        *out++ = *from++;
                         if (len > 1)
-                            PUP(out) = PUP(from);
+                            *out++ = *from++;
                     }
                 }
                 else {
                     from = out - dist;          /* copy direct from output */
                     do {                        /* minimum length is three */
-                        PUP(out) = PUP(from);
-                        PUP(out) = PUP(from);
-                        PUP(out) = PUP(from);
+                        *out++ = *from++;
+                        *out++ = *from++;
+                        *out++ = *from++;
                         len -= 3;
                     } while (len > 2);
                     if (len) {
-                        PUP(out) = PUP(from);
+                        *out++ = *from++;
                         if (len > 1)
-                            PUP(out) = PUP(from);
+                            *out++ = *from++;
                     }
                 }
             }
             else if ((op & 64) == 0) {          /* 2nd level distance code */
-                this = dcode[this.val + (hold & ((1U << op) - 1))];
+                here = dcode[here.val + (hold & ((1U << op) - 1))];
                 goto dodist;
             }
             else {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid distance code";
 #endif
@@ -278,7 +283,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
             }
         }
         else if ((op & 64) == 0) {              /* 2nd level length code */
-            this = lcode[this.val + (hold & ((1U << op) - 1))];
+            here = lcode[here.val + (hold & ((1U << op) - 1))];
             goto dolen;
         }
         else if (op & 32) {                     /* end-of-block */
@@ -287,8 +292,8 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
             break;
         }
         else {
-#ifdef SMALL  
-	    strm->msg = "error";
+#ifdef SMALL
+            strm->msg = "error";
 #else
             strm->msg = (char *)"invalid literal/length code";
 #endif
@@ -304,8 +309,8 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
     hold &= (1U << bits) - 1;
 
     /* update state and return */
-    strm->next_in = in + OFF;
-    strm->next_out = out + OFF;
+    strm->next_in = in;
+    strm->next_out = out;
     strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last));
     strm->avail_out = (unsigned)(out < end ?
                                  257 + (end - out) : 257 - (out - end));
@@ -318,7 +323,7 @@ unsigned start;         /* inflate()'s starting value for strm->avail_out */
    inflate_fast() speedups that turned out slower (on a PowerPC G3 750CXe):
    - Using bit fields for code structure
    - Different op definition to avoid & for extra bits (do & for table bits)
-   - Three separate decoding do-loops for direct, window, and write == 0
+   - Three separate decoding do-loops for direct, window, and wnext == 0
    - Special case for distance > 1 copies to do overlapped load and store copy
    - Explicit branch predictions (based on measured branch probabilities)
    - Deferring match copy and interspersed it with decoding subsequent codes
diff --git a/sys/lib/libz/inffast.h b/sys/lib/libz/inffast.h
index ab391257e72..e5c1aa4ca8c 100644
--- a/sys/lib/libz/inffast.h
+++ b/sys/lib/libz/inffast.h
@@ -1,6 +1,5 @@
-/*	$OpenBSD: inffast.h,v 1.6 2003/12/16 23:57:48 millert Exp $	*/
 /* inffast.h -- header to use inffast.c
- * Copyright (C) 1995-2003 Mark Adler
+ * Copyright (C) 1995-2003, 2010 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,4 +8,4 @@
    subject to change. Applications should only use zlib.h.
  */
 
-void inflate_fast OF((z_streamp strm, unsigned start));
+void ZLIB_INTERNAL inflate_fast OF((z_streamp strm, unsigned start));
diff --git a/sys/lib/libz/inffixed.h b/sys/lib/libz/inffixed.h
index d2ef636d4b7..d6283277694 100644
--- a/sys/lib/libz/inffixed.h
+++ b/sys/lib/libz/inffixed.h
@@ -1,11 +1,10 @@
-/*	$OpenBSD: inffixed.h,v 1.3 2003/12/16 23:57:48 millert Exp $	*/
     /* inffixed.h -- table for decoding fixed codes
      * Generated automatically by makefixed().
      */
 
-    /* WARNING: this file should *not* be used by applications. It
-       is part of the implementation of the compression library and
-       is subject to change. Applications should only use zlib.h.
+    /* WARNING: this file should *not* be used by applications.
+       It is part of the implementation of this library and is
+       subject to change. Applications should only use zlib.h.
      */
 
     static const code lenfix[512] = {
diff --git a/sys/lib/libz/inflate.c b/sys/lib/libz/inflate.c
index 27bfb1c5fd6..5e3d8ef2169 100644
--- a/sys/lib/libz/inflate.c
+++ b/sys/lib/libz/inflate.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: inflate.c,v 1.15 2019/06/01 11:39:57 jca Exp $	*/
+/*	$OpenBSD: inflate.c,v 1.16 2021/07/04 14:24:49 tb Exp $ */
 /* inflate.c -- zlib decompression
- * Copyright (C) 1995-2005 Mark Adler
+ * Copyright (C) 1995-2016 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -46,7 +46,7 @@
  * - Rearrange window copies in inflate_fast() for speed and simplification
  * - Unroll last copy for window match in inflate_fast()
  * - Use local copies of window variables in inflate_fast() for speed
- * - Pull out common write == 0 case for speed in inflate_fast()
+ * - Pull out common wnext == 0 case for speed in inflate_fast()
  * - Make op and len in inflate_fast() unsigned for consistency
  * - Add FAR to lcode and dcode declarations in inflate_fast()
  * - Simplified bad distance check in inflate_fast()
@@ -93,53 +93,104 @@
 #endif
 
 /* function prototypes */
+local int inflateStateCheck OF((z_streamp strm));
 local void fixedtables OF((struct inflate_state FAR *state));
-local int updatewindow OF((z_streamp strm, unsigned out));
+local int updatewindow OF((z_streamp strm, const unsigned char FAR *end,
+                           unsigned copy));
 #ifdef BUILDFIXED
    void makefixed OF((void));
 #endif
-local unsigned syncsearch OF((unsigned FAR *have, z_const unsigned char FAR *buf,
+local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf,
                               unsigned len));
 
-int ZEXPORT inflateReset(strm)
+local int inflateStateCheck(strm)
 z_streamp strm;
 {
     struct inflate_state FAR *state;
+    if (strm == Z_NULL ||
+        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
+        return 1;
+    state = (struct inflate_state FAR *)strm->state;
+    if (state == Z_NULL || state->strm != strm ||
+        state->mode < HEAD || state->mode > SYNC)
+        return 1;
+    return 0;
+}
 
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+int ZEXPORT inflateResetKeep(strm)
+z_streamp strm;
+{
+    struct inflate_state FAR *state;
+
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
     strm->total_in = strm->total_out = state->total = 0;
     strm->msg = Z_NULL;
-    strm->adler = 1;        /* to support ill-conceived Java test suite */
+    if (state->wrap)        /* to support ill-conceived Java test suite */
+        strm->adler = state->wrap & 1;
     state->mode = HEAD;
     state->last = 0;
     state->havedict = 0;
     state->dmax = 32768U;
     state->head = Z_NULL;
-    state->wsize = 0;
-    state->whave = 0;
-    state->write = 0;
     state->hold = 0;
     state->bits = 0;
     state->lencode = state->distcode = state->next = state->codes;
+    state->sane = 1;
+    state->back = -1;
     Tracev((stderr, "inflate: reset\n"));
     return Z_OK;
 }
 
-int ZEXPORT inflatePrime(strm, bits, value)
+int ZEXPORT inflateReset(strm)
 z_streamp strm;
-int bits;
-int value;
 {
     struct inflate_state FAR *state;
 
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
-    if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR;
-    value &= (1L << bits) - 1;
-    state->hold += value << state->bits;
-    state->bits += bits;
-    return Z_OK;
+    state->wsize = 0;
+    state->whave = 0;
+    state->wnext = 0;
+    return inflateResetKeep(strm);
+}
+
+int ZEXPORT inflateReset2(strm, windowBits)
+z_streamp strm;
+int windowBits;
+{
+    int wrap;
+    struct inflate_state FAR *state;
+
+    /* get the state */
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
+    state = (struct inflate_state FAR *)strm->state;
+
+    /* extract wrap request from windowBits parameter */
+    if (windowBits < 0) {
+        wrap = 0;
+        windowBits = -windowBits;
+    }
+    else {
+        wrap = (windowBits >> 4) + 5;
+#ifdef GUNZIP
+        if (windowBits < 48)
+            windowBits &= 15;
+#endif
+    }
+
+    /* set number of window bits, free window if different */
+    if (windowBits && (windowBits < 8 || windowBits > 15))
+        return Z_STREAM_ERROR;
+    if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
+        ZFREE(strm, state->window);
+        state->window = Z_NULL;
+    }
+
+    /* update state and reset the rest of it */
+    state->wrap = wrap;
+    state->wbits = (unsigned)windowBits;
+    return inflateReset(strm);
 }
 
 int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
@@ -148,6 +199,7 @@ int windowBits;
 const char *version;
 int stream_size;
 {
+    int ret;
     struct inflate_state FAR *state;
 
     if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
@@ -156,33 +208,33 @@ int stream_size;
     if (strm == Z_NULL) return Z_STREAM_ERROR;
     strm->msg = Z_NULL;                 /* in case we return an error */
     if (strm->zalloc == (alloc_func)0) {
+#ifdef Z_SOLO
+        return Z_STREAM_ERROR;
+#else
         strm->zalloc = zcalloc;
         strm->opaque = (voidpf)0;
+#endif
     }
-    if (strm->zfree == (free_func)0) strm->zfree = zcfree;
+    if (strm->zfree == (free_func)0)
+#ifdef Z_SOLO
+        return Z_STREAM_ERROR;
+#else
+        strm->zfree = zcfree;
+#endif
     state = (struct inflate_state FAR *)
             ZALLOC(strm, 1, sizeof(struct inflate_state));
     if (state == Z_NULL) return Z_MEM_ERROR;
     Tracev((stderr, "inflate: allocated\n"));
     strm->state = (struct internal_state FAR *)state;
-    if (windowBits < 0) {
-        state->wrap = 0;
-        windowBits = -windowBits;
-    }
-    else {
-        state->wrap = (windowBits >> 4) + 1;
-#ifdef GUNZIP
-        if (windowBits < 48) windowBits &= 15;
-#endif
-    }
-    if (windowBits < 8 || windowBits > 15) {
+    state->strm = strm;
+    state->window = Z_NULL;
+    state->mode = HEAD;     /* to pass state test in inflateReset2() */
+    ret = inflateReset2(strm, windowBits);
+    if (ret != Z_OK) {
         ZFREE(strm, state);
         strm->state = Z_NULL;
-        return Z_STREAM_ERROR;
     }
-    state->wbits = (unsigned)windowBits;
-    state->window = Z_NULL;
-    return inflateReset(strm);
+    return ret;
 }
 
 int ZEXPORT inflateInit_(strm, version, stream_size)
@@ -193,6 +245,27 @@ int stream_size;
     return inflateInit2_(strm, DEF_WBITS, version, stream_size);
 }
 
+int ZEXPORT inflatePrime(strm, bits, value)
+z_streamp strm;
+int bits;
+int value;
+{
+    struct inflate_state FAR *state;
+
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
+    state = (struct inflate_state FAR *)strm->state;
+    if (bits < 0) {
+        state->hold = 0;
+        state->bits = 0;
+        return Z_OK;
+    }
+    if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;
+    value &= (1L << bits) - 1;
+    state->hold += (unsigned)value << state->bits;
+    state->bits += (uInt)bits;
+    return Z_OK;
+}
+
 /*
    Return state with length and distance decoding tables and index sizes set to
    fixed code decoding.  Normally this returns fixed tables from inffixed.h.
@@ -287,8 +360,8 @@ void makefixed()
     low = 0;
     for (;;) {
         if ((low % 7) == 0) printf("\n        ");
-        printf("{%u,%u,%d}", state.lencode[low].op, state.lencode[low].bits,
-               state.lencode[low].val);
+        printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
+               state.lencode[low].bits, state.lencode[low].val);
         if (++low == size) break;
         putchar(',');
     }
@@ -321,12 +394,13 @@ void makefixed()
    output will fall in the output data, making match copies simpler and faster.
    The advantage may be dependent on the size of the processor's data caches.
  */
-local int updatewindow(strm, out)
+local int updatewindow(strm, end, copy)
 z_streamp strm;
-unsigned out;
+const Bytef *end;
+unsigned copy;
 {
     struct inflate_state FAR *state;
-    unsigned copy, dist;
+    unsigned dist;
 
     state = (struct inflate_state FAR *)strm->state;
 
@@ -341,30 +415,29 @@ unsigned out;
     /* if window not in use yet, initialize */
     if (state->wsize == 0) {
         state->wsize = 1U << state->wbits;
-        state->write = 0;
+        state->wnext = 0;
         state->whave = 0;
     }
 
     /* copy state->wsize or less output bytes into the circular window */
-    copy = out - strm->avail_out;
     if (copy >= state->wsize) {
-        zmemcpy(state->window, strm->next_out - state->wsize, state->wsize);
-        state->write = 0;
+        zmemcpy(state->window, end - state->wsize, state->wsize);
+        state->wnext = 0;
         state->whave = state->wsize;
     }
     else {
-        dist = state->wsize - state->write;
+        dist = state->wsize - state->wnext;
         if (dist > copy) dist = copy;
-        zmemcpy(state->window + state->write, strm->next_out - copy, dist);
+        zmemcpy(state->window + state->wnext, end - copy, dist);
         copy -= dist;
         if (copy) {
-            zmemcpy(state->window, strm->next_out - copy, copy);
-            state->write = copy;
+            zmemcpy(state->window, end - copy, copy);
+            state->wnext = copy;
             state->whave = state->wsize;
         }
         else {
-            state->write += dist;
-            if (state->write == state->wsize) state->write = 0;
+            state->wnext += dist;
+            if (state->wnext == state->wsize) state->wnext = 0;
             if (state->whave < state->wsize) state->whave += dist;
         }
     }
@@ -465,11 +538,6 @@ unsigned out;
         bits -= bits & 7; \
     } while (0)
 
-/* Reverse the bytes in a 32-bit value */
-#define REVERSE(q) \
-    ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
-     (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
-
 /*
    inflate() uses a state machine to process as much input data and generate as
    much output data as possible before returning.  The state machine is
@@ -565,7 +633,7 @@ int flush;
     unsigned in, out;           /* save starting available input and output */
     unsigned copy;              /* number of stored or match bytes to copy */
     unsigned char FAR *from;    /* where to copy match bytes from */
-    code this;                  /* current decoding table entry */
+    code here;                  /* current decoding table entry */
     code last;                  /* parent table entry */
     unsigned len;               /* length to copy for repeats, bits to drop */
     int ret;                    /* return code */
@@ -575,7 +643,7 @@ int flush;
     static const unsigned short order[19] = /* permutation of code lengths */
         {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
 
-    if (strm == Z_NULL || strm->state == Z_NULL || strm->next_out == Z_NULL ||
+    if (inflateStateCheck(strm) || strm->next_out == Z_NULL ||
         (strm->next_in == Z_NULL && strm->avail_in != 0))
         return Z_STREAM_ERROR;
 
@@ -595,6 +663,8 @@ int flush;
             NEEDBITS(16);
 #ifdef GUNZIP
             if ((state->wrap & 2) && hold == 0x8b1f) {  /* gzip header */
+                if (state->wbits == 0)
+                    state->wbits = 15;
                 state->check = crc32(0L, Z_NULL, 0);
                 CRC2(state->check, hold);
                 INITBITS();
@@ -609,8 +679,8 @@ int flush;
             if (
 #endif
                 ((BITS(8) << 8) + (hold >> 8)) % 31) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"incorrect header check";
 #endif
@@ -618,8 +688,8 @@ int flush;
                 break;
             }
             if (BITS(4) != Z_DEFLATED) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"unknown compression method";
 #endif
@@ -627,17 +697,19 @@ int flush;
                 break;
             }
             DROPBITS(4);
-	    len = BITS(4) + 8;
-	    if (len > state->wbits) {
-#ifdef SMALL  
-		strm->msg = "error";
+            len = BITS(4) + 8;
+            if (state->wbits == 0)
+                state->wbits = len;
+            if (len > 15 || len > state->wbits) {
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid window size";
 #endif
                 state->mode = BAD;
                 break;
             }
-	    state->dmax = 1U << len;
+            state->dmax = 1U << len;
             Tracev((stderr, "inflate:   zlib header ok\n"));
             strm->adler = state->check = adler32(0L, Z_NULL, 0);
             state->mode = hold & 0x200 ? DICTID : TYPE;
@@ -648,8 +720,8 @@ int flush;
             NEEDBITS(16);
             state->flags = (int)(hold);
             if ((state->flags & 0xff) != Z_DEFLATED) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"unknown compression method";
 #endif
@@ -657,8 +729,8 @@ int flush;
                 break;
             }
             if (state->flags & 0xe000) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"unknown header flags set";
 #endif
@@ -667,14 +739,16 @@ int flush;
             }
             if (state->head != Z_NULL)
                 state->head->text = (int)((hold >> 8) & 1);
-            if (state->flags & 0x0200) CRC2(state->check, hold);
+            if ((state->flags & 0x0200) && (state->wrap & 4))
+                CRC2(state->check, hold);
             INITBITS();
             state->mode = TIME;
         case TIME:
             NEEDBITS(32);
             if (state->head != Z_NULL)
                 state->head->time = hold;
-            if (state->flags & 0x0200) CRC4(state->check, hold);
+            if ((state->flags & 0x0200) && (state->wrap & 4))
+                CRC4(state->check, hold);
             INITBITS();
             state->mode = OS;
         case OS:
@@ -683,7 +757,8 @@ int flush;
                 state->head->xflags = (int)(hold & 0xff);
                 state->head->os = (int)(hold >> 8);
             }
-            if (state->flags & 0x0200) CRC2(state->check, hold);
+            if ((state->flags & 0x0200) && (state->wrap & 4))
+                CRC2(state->check, hold);
             INITBITS();
             state->mode = EXLEN;
         case EXLEN:
@@ -692,7 +767,8 @@ int flush;
                 state->length = (unsigned)(hold);
                 if (state->head != Z_NULL)
                     state->head->extra_len = (unsigned)hold;
-                if (state->flags & 0x0200) CRC2(state->check, hold);
+                if ((state->flags & 0x0200) && (state->wrap & 4))
+                    CRC2(state->check, hold);
                 INITBITS();
             }
             else if (state->head != Z_NULL)
@@ -710,7 +786,7 @@ int flush;
                                 len + copy > state->head->extra_max ?
                                 state->head->extra_max - len : copy);
                     }
-                    if (state->flags & 0x0200)
+                    if ((state->flags & 0x0200) && (state->wrap & 4))
                         state->check = crc32(state->check, next, copy);
                     have -= copy;
                     next += copy;
@@ -729,9 +805,9 @@ int flush;
                     if (state->head != Z_NULL &&
                             state->head->name != Z_NULL &&
                             state->length < state->head->name_max)
-                        state->head->name[state->length++] = len;
+                        state->head->name[state->length++] = (Bytef)len;
                 } while (len && copy < have);
-                if (state->flags & 0x0200)
+                if ((state->flags & 0x0200) && (state->wrap & 4))
                     state->check = crc32(state->check, next, copy);
                 have -= copy;
                 next += copy;
@@ -750,9 +826,9 @@ int flush;
                     if (state->head != Z_NULL &&
                             state->head->comment != Z_NULL &&
                             state->length < state->head->comm_max)
-                        state->head->comment[state->length++] = len;
+                        state->head->comment[state->length++] = (Bytef)len;
                 } while (len && copy < have);
-                if (state->flags & 0x0200)
+                if ((state->flags & 0x0200) && (state->wrap & 4))
                     state->check = crc32(state->check, next, copy);
                 have -= copy;
                 next += copy;
@@ -764,9 +840,9 @@ int flush;
         case HCRC:
             if (state->flags & 0x0200) {
                 NEEDBITS(16);
-                if (hold != (state->check & 0xffff)) {
-#ifdef SMALL  
-		    strm->msg = "error";
+                if ((state->wrap & 4) && hold != (state->check & 0xffff)) {
+#ifdef SMALL
+                    strm->msg = "error";
 #else
                     strm->msg = (char *)"header crc mismatch";
 #endif
@@ -785,7 +861,7 @@ int flush;
 #endif
         case DICTID:
             NEEDBITS(32);
-            strm->adler = state->check = REVERSE(hold);
+            strm->adler = state->check = ZSWAP32(hold);
             INITBITS();
             state->mode = DICT;
         case DICT:
@@ -796,7 +872,7 @@ int flush;
             strm->adler = state->check = adler32(0L, Z_NULL, 0);
             state->mode = TYPE;
         case TYPE:
-            if (flush == Z_BLOCK) goto inf_leave;
+            if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
         case TYPEDO:
             if (state->last) {
                 BYTEBITS();
@@ -816,7 +892,11 @@ int flush;
                 fixedtables(state);
                 Tracev((stderr, "inflate:     fixed codes block%s\n",
                         state->last ? " (last)" : ""));
-                state->mode = LEN;              /* decode codes */
+                state->mode = LEN_;             /* decode codes */
+                if (flush == Z_TREES) {
+                    DROPBITS(2);
+                    goto inf_leave;
+                }
                 break;
             case 2:                             /* dynamic block */
                 Tracev((stderr, "inflate:     dynamic codes block%s\n",
@@ -824,8 +904,8 @@ int flush;
                 state->mode = TABLE;
                 break;
             case 3:
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid block type";
 #endif
@@ -837,8 +917,8 @@ int flush;
             BYTEBITS();                         /* go to byte boundary */
             NEEDBITS(32);
             if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid stored block lengths";
 #endif
@@ -849,6 +929,9 @@ int flush;
             Tracev((stderr, "inflate:       stored length %u\n",
                     state->length));
             INITBITS();
+            state->mode = COPY_;
+            if (flush == Z_TREES) goto inf_leave;
+        case COPY_:
             state->mode = COPY;
         case COPY:
             copy = state->length;
@@ -877,8 +960,8 @@ int flush;
             DROPBITS(4);
 #ifndef PKZIP_BUG_WORKAROUND
             if (state->nlen > 286 || state->ndist > 30) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"too many length or distance symbols";
 #endif
@@ -898,13 +981,13 @@ int flush;
             while (state->have < 19)
                 state->lens[order[state->have++]] = 0;
             state->next = state->codes;
-            state->lencode = (code const FAR *)(state->next);
+            state->lencode = (const code FAR *)(state->next);
             state->lenbits = 7;
             ret = inflate_table(CODES, state->lens, 19, &(state->next),
                                 &(state->lenbits), state->work);
             if (ret) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid code lengths set";
 #endif
@@ -917,22 +1000,21 @@ int flush;
         case CODELENS:
             while (state->have < state->nlen + state->ndist) {
                 for (;;) {
-                    this = state->lencode[BITS(state->lenbits)];
-                    if ((unsigned)(this.bits) <= bits) break;
+                    here = state->lencode[BITS(state->lenbits)];
+                    if ((unsigned)(here.bits) <= bits) break;
                     PULLBYTE();
                 }
-                if (this.val < 16) {
-                    NEEDBITS(this.bits);
-                    DROPBITS(this.bits);
-                    state->lens[state->have++] = this.val;
+                if (here.val < 16) {
+                    DROPBITS(here.bits);
+                    state->lens[state->have++] = here.val;
                 }
                 else {
-                    if (this.val == 16) {
-                        NEEDBITS(this.bits + 2);
-                        DROPBITS(this.bits);
+                    if (here.val == 16) {
+                        NEEDBITS(here.bits + 2);
+                        DROPBITS(here.bits);
                         if (state->have == 0) {
-#ifdef SMALL  
-			    strm->msg = "error";
+#ifdef SMALL
+                            strm->msg = "error";
 #else
                             strm->msg = (char *)"invalid bit length repeat";
 #endif
@@ -943,23 +1025,23 @@ int flush;
                         copy = 3 + BITS(2);
                         DROPBITS(2);
                     }
-                    else if (this.val == 17) {
-                        NEEDBITS(this.bits + 3);
-                        DROPBITS(this.bits);
+                    else if (here.val == 17) {
+                        NEEDBITS(here.bits + 3);
+                        DROPBITS(here.bits);
                         len = 0;
                         copy = 3 + BITS(3);
                         DROPBITS(3);
                     }
                     else {
-                        NEEDBITS(this.bits + 7);
-                        DROPBITS(this.bits);
+                        NEEDBITS(here.bits + 7);
+                        DROPBITS(here.bits);
                         len = 0;
                         copy = 11 + BITS(7);
                         DROPBITS(7);
                     }
                     if (state->have + copy > state->nlen + state->ndist) {
-#ifdef SMALL  
-			strm->msg = "error";
+#ifdef SMALL
+                        strm->msg = "error";
 #else
                         strm->msg = (char *)"invalid bit length repeat";
 #endif
@@ -974,28 +1056,41 @@ int flush;
             /* handle error breaks in while */
             if (state->mode == BAD) break;
 
-            /* build code tables */
+            /* check for end-of-block code (better have one) */
+            if (state->lens[256] == 0) {
+#ifdef SMALL
+                strm->msg = "error";
+#else
+                strm->msg = (char *)"invalid code -- missing end-of-block";
+#endif
+                state->mode = BAD;
+                break;
+            }
+
+            /* build code tables -- note: do not change the lenbits or distbits
+               values here (9 and 6) without reading the comments in inftrees.h
+               concerning the ENOUGH constants, which depend on those values */
             state->next = state->codes;
-            state->lencode = (code const FAR *)(state->next);
+            state->lencode = (const code FAR *)(state->next);
             state->lenbits = 9;
             ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
                                 &(state->lenbits), state->work);
             if (ret) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid literal/lengths set";
 #endif
                 state->mode = BAD;
                 break;
             }
-            state->distcode = (code const FAR *)(state->next);
+            state->distcode = (const code FAR *)(state->next);
             state->distbits = 6;
             ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
                             &(state->next), &(state->distbits), state->work);
             if (ret) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid distances set";
 #endif
@@ -1003,6 +1098,9 @@ int flush;
                 break;
             }
             Tracev((stderr, "inflate:       codes ok\n"));
+            state->mode = LEN_;
+            if (flush == Z_TREES) goto inf_leave;
+        case LEN_:
             state->mode = LEN;
         case LEN:
 #ifndef SLOW
@@ -1010,108 +1108,114 @@ int flush;
                 RESTORE();
                 inflate_fast(strm, out);
                 LOAD();
+                if (state->mode == TYPE)
+                    state->back = -1;
                 break;
             }
 #endif
+            state->back = 0;
             for (;;) {
-                this = state->lencode[BITS(state->lenbits)];
-                if ((unsigned)(this.bits) <= bits) break;
+                here = state->lencode[BITS(state->lenbits)];
+                if ((unsigned)(here.bits) <= bits) break;
                 PULLBYTE();
             }
-            if (this.op && (this.op & 0xf0) == 0) {
-                last = this;
+            if (here.op && (here.op & 0xf0) == 0) {
+                last = here;
                 for (;;) {
-                    this = state->lencode[last.val +
+                    here = state->lencode[last.val +
                             (BITS(last.bits + last.op) >> last.bits)];
-                    if ((unsigned)(last.bits + this.bits) <= bits) break;
+                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                     PULLBYTE();
                 }
                 DROPBITS(last.bits);
+                state->back += last.bits;
             }
-            DROPBITS(this.bits);
-            state->length = (unsigned)this.val;
-            if ((int)(this.op) == 0) {
-                Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
+            DROPBITS(here.bits);
+            state->back += here.bits;
+            state->length = (unsigned)here.val;
+            if ((int)(here.op) == 0) {
+                Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
                         "inflate:         literal '%c'\n" :
-                        "inflate:         literal 0x%02x\n", this.val));
+                        "inflate:         literal 0x%02x\n", here.val));
                 state->mode = LIT;
                 break;
             }
-            if (this.op & 32) {
+            if (here.op & 32) {
                 Tracevv((stderr, "inflate:         end of block\n"));
+                state->back = -1;
                 state->mode = TYPE;
                 break;
             }
-            if (this.op & 64) {
-#ifdef SMALL  
-		strm->msg = "error";
+            if (here.op & 64) {
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid literal/length code";
 #endif
                 state->mode = BAD;
                 break;
             }
-            state->extra = (unsigned)(this.op) & 15;
+            state->extra = (unsigned)(here.op) & 15;
             state->mode = LENEXT;
         case LENEXT:
             if (state->extra) {
                 NEEDBITS(state->extra);
                 state->length += BITS(state->extra);
                 DROPBITS(state->extra);
+                state->back += state->extra;
             }
             Tracevv((stderr, "inflate:         length %u\n", state->length));
+            state->was = state->length;
             state->mode = DIST;
         case DIST:
             for (;;) {
-                this = state->distcode[BITS(state->distbits)];
-                if ((unsigned)(this.bits) <= bits) break;
+                here = state->distcode[BITS(state->distbits)];
+                if ((unsigned)(here.bits) <= bits) break;
                 PULLBYTE();
             }
-            if ((this.op & 0xf0) == 0) {
-                last = this;
+            if ((here.op & 0xf0) == 0) {
+                last = here;
                 for (;;) {
-                    this = state->distcode[last.val +
+                    here = state->distcode[last.val +
                             (BITS(last.bits + last.op) >> last.bits)];
-                    if ((unsigned)(last.bits + this.bits) <= bits) break;
+                    if ((unsigned)(last.bits + here.bits) <= bits) break;
                     PULLBYTE();
                 }
                 DROPBITS(last.bits);
+                state->back += last.bits;
             }
-            DROPBITS(this.bits);
-            if (this.op & 64) {
-#ifdef SMALL  
-		strm->msg = "error";
+            DROPBITS(here.bits);
+            state->back += here.bits;
+            if (here.op & 64) {
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid distance code";
 #endif
                 state->mode = BAD;
                 break;
             }
-            state->offset = (unsigned)this.val;
-            state->extra = (unsigned)(this.op) & 15;
+            state->offset = (unsigned)here.val;
+            state->extra = (unsigned)(here.op) & 15;
             state->mode = DISTEXT;
         case DISTEXT:
             if (state->extra) {
                 NEEDBITS(state->extra);
                 state->offset += BITS(state->extra);
                 DROPBITS(state->extra);
+                state->back += state->extra;
             }
 #ifdef INFLATE_STRICT
             if (state->offset > state->dmax) {
-                strm->msg = (char *)"invalid distance too far back";
-                state->mode = BAD;
-                break;
-            }
-#endif
-            if (state->offset > state->whave + out - left) {
-#ifdef SMALL  
-		strm->msg = "error";
+#ifdef SMALL
+                strm->msg = "error";
 #else
                 strm->msg = (char *)"invalid distance too far back";
 #endif
                 state->mode = BAD;
                 break;
             }
+#endif
             Tracevv((stderr, "inflate:         distance %u\n", state->offset));
             state->mode = MATCH;
         case MATCH:
@@ -1119,12 +1223,36 @@ int flush;
             copy = out - left;
             if (state->offset > copy) {         /* copy from window */
                 copy = state->offset - copy;
-                if (copy > state->write) {
-                    copy -= state->write;
+                if (copy > state->whave) {
+                    if (state->sane) {
+#ifdef SMALL
+                        strm->msg = "error";
+#else
+                        strm->msg = (char *)"invalid distance too far back";
+#endif
+                        state->mode = BAD;
+                        break;
+                    }
+#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
+                    Trace((stderr, "inflate.c too far\n"));
+                    copy -= state->whave;
+                    if (copy > state->length) copy = state->length;
+                    if (copy > left) copy = left;
+                    left -= copy;
+                    state->length -= copy;
+                    do {
+                        *put++ = 0;
+                    } while (--copy);
+                    if (state->length == 0) state->mode = LEN;
+                    break;
+#endif
+                }
+                if (copy > state->wnext) {
+                    copy -= state->wnext;
                     from = state->window + (state->wsize - copy);
                 }
                 else
-                    from = state->window + (state->write - copy);
+                    from = state->window + (state->wnext - copy);
                 if (copy > state->length) copy = state->length;
             }
             else {                              /* copy from output */
@@ -1151,17 +1279,17 @@ int flush;
                 out -= left;
                 strm->total_out += out;
                 state->total += out;
-                if (out)
+                if ((state->wrap & 4) && out)
                     strm->adler = state->check =
                         UPDATE(state->check, put - out, out);
                 out = left;
-                if ((
+                if ((state->wrap & 4) && (
 #ifdef GUNZIP
                      state->flags ? hold :
 #endif
-                     REVERSE(hold)) != state->check) {
-#ifdef SMALL  
-		    strm->msg = "error";
+                     ZSWAP32(hold)) != state->check) {
+#ifdef SMALL
+                    strm->msg = "error";
 #else
                     strm->msg = (char *)"incorrect data check";
 #endif
@@ -1177,8 +1305,8 @@ int flush;
             if (state->wrap && state->flags) {
                 NEEDBITS(32);
                 if (hold != (state->total & 0xffffffffUL)) {
-#ifdef SMALL  
-		    strm->msg = "error";
+#ifdef SMALL
+                    strm->msg = "error";
 #else
                     strm->msg = (char *)"incorrect length check";
 #endif
@@ -1211,8 +1339,9 @@ int flush;
      */
   inf_leave:
     RESTORE();
-    if (state->wsize || (state->mode < CHECK && out != strm->avail_out))
-        if (updatewindow(strm, out)) {
+    if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
+            (state->mode < CHECK || flush != Z_FINISH)))
+        if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
             state->mode = MEM;
             return Z_MEM_ERROR;
         }
@@ -1221,11 +1350,12 @@ int flush;
     strm->total_in += in;
     strm->total_out += out;
     state->total += out;
-    if (state->wrap && out)
+    if ((state->wrap & 4) && out)
         strm->adler = state->check =
             UPDATE(state->check, strm->next_out - out, out);
-    strm->data_type = state->bits + (state->last ? 64 : 0) +
-                      (state->mode == TYPE ? 128 : 0);
+    strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
+                      (state->mode == TYPE ? 128 : 0) +
+                      (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
     if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
         ret = Z_BUF_ERROR;
     return ret;
@@ -1235,7 +1365,7 @@ int ZEXPORT inflateEnd(strm)
 z_streamp strm;
 {
     struct inflate_state FAR *state;
-    if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
+    if (inflateStateCheck(strm))
         return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
     if (state->window != Z_NULL) ZFREE(strm, state->window);
@@ -1245,43 +1375,59 @@ z_streamp strm;
     return Z_OK;
 }
 
+int ZEXPORT inflateGetDictionary(strm, dictionary, dictLength)
+z_streamp strm;
+Bytef *dictionary;
+uInt *dictLength;
+{
+    struct inflate_state FAR *state;
+
+    /* check state */
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
+    state = (struct inflate_state FAR *)strm->state;
+
+    /* copy dictionary */
+    if (state->whave && dictionary != Z_NULL) {
+        zmemcpy(dictionary, state->window + state->wnext,
+                state->whave - state->wnext);
+        zmemcpy(dictionary + state->whave - state->wnext,
+                state->window, state->wnext);
+    }
+    if (dictLength != Z_NULL)
+        *dictLength = state->whave;
+    return Z_OK;
+}
+
 int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
 z_streamp strm;
 const Bytef *dictionary;
 uInt dictLength;
 {
     struct inflate_state FAR *state;
-    unsigned long id;
+    unsigned long dictid;
+    int ret;
 
     /* check state */
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
     if (state->wrap != 0 && state->mode != DICT)
         return Z_STREAM_ERROR;
 
-    /* check for correct dictionary id */
+    /* check for correct dictionary identifier */
     if (state->mode == DICT) {
-        id = adler32(0L, Z_NULL, 0);
-        id = adler32(id, dictionary, dictLength);
-        if (id != state->check)
+        dictid = adler32(0L, Z_NULL, 0);
+        dictid = adler32(dictid, dictionary, dictLength);
+        if (dictid != state->check)
             return Z_DATA_ERROR;
     }
 
-    /* copy dictionary to window */
-    if (updatewindow(strm, strm->avail_out)) {
+    /* copy dictionary to window using updatewindow(), which will amend the
+       existing dictionary if appropriate */
+    ret = updatewindow(strm, dictionary + dictLength, dictLength);
+    if (ret) {
         state->mode = MEM;
         return Z_MEM_ERROR;
     }
-    if (dictLength > state->wsize) {
-        zmemcpy(state->window, dictionary + dictLength - state->wsize,
-                state->wsize);
-        state->whave = state->wsize;
-    }
-    else {
-        zmemcpy(state->window + state->wsize - dictLength, dictionary,
-                dictLength);
-        state->whave = dictLength;
-    }
     state->havedict = 1;
     Tracev((stderr, "inflate:   dictionary set\n"));
     return Z_OK;
@@ -1294,7 +1440,7 @@ gz_headerp head;
     struct inflate_state FAR *state;
 
     /* check state */
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
     if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
 
@@ -1317,7 +1463,7 @@ gz_headerp head;
  */
 local unsigned syncsearch(have, buf, len)
 unsigned FAR *have;
-z_const unsigned char FAR *buf;
+const unsigned char FAR *buf;
 unsigned len;
 {
     unsigned got;
@@ -1347,7 +1493,7 @@ z_streamp strm;
     struct inflate_state FAR *state;
 
     /* check parameters */
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
     if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
 
@@ -1394,7 +1540,7 @@ z_streamp strm;
 {
     struct inflate_state FAR *state;
 
-    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)strm->state;
     return state->mode == STORED && state->bits == 0;
 }
@@ -1409,8 +1555,7 @@ z_streamp source;
     unsigned wsize;
 
     /* check input */
-    if (dest == Z_NULL || source == Z_NULL || source->state == Z_NULL ||
-        source->zalloc == (alloc_func)0 || source->zfree == (free_func)0)
+    if (inflateStateCheck(source) || dest == Z_NULL)
         return Z_STREAM_ERROR;
     state = (struct inflate_state FAR *)source->state;
 
@@ -1429,8 +1574,9 @@ z_streamp source;
     }
 
     /* copy state */
-    zmemcpy(dest, source, sizeof(z_stream));
-    zmemcpy(copy, state, sizeof(struct inflate_state));
+    zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
+    zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
+    copy->strm = dest;
     if (state->lencode >= state->codes &&
         state->lencode <= state->codes + ENOUGH - 1) {
         copy->lencode = copy->codes + (state->lencode - state->codes);
@@ -1445,3 +1591,58 @@ z_streamp source;
     dest->state = (struct internal_state FAR *)copy;
     return Z_OK;
 }
+
+int ZEXPORT inflateUndermine(strm, subvert)
+z_streamp strm;
+int subvert;
+{
+    struct inflate_state FAR *state;
+
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
+    state = (struct inflate_state FAR *)strm->state;
+#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
+    state->sane = !subvert;
+    return Z_OK;
+#else
+    (void)subvert;
+    state->sane = 1;
+    return Z_DATA_ERROR;
+#endif
+}
+
+int ZEXPORT inflateValidate(strm, check)
+z_streamp strm;
+int check;
+{
+    struct inflate_state FAR *state;
+
+    if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
+    state = (struct inflate_state FAR *)strm->state;
+    if (check)
+        state->wrap |= 4;
+    else
+        state->wrap &= ~4;
+    return Z_OK;
+}
+
+long ZEXPORT inflateMark(strm)
+z_streamp strm;
+{
+    struct inflate_state FAR *state;
+
+    if (inflateStateCheck(strm))
+        return -(1L << 16);
+    state = (struct inflate_state FAR *)strm->state;
+    return (long)(((unsigned long)((long)state->back)) << 16) +
+        (state->mode == COPY ? state->length :
+            (state->mode == MATCH ? state->was - state->length : 0));
+}
+
+unsigned long ZEXPORT inflateCodesUsed(strm)
+z_streamp strm;
+{
+    struct inflate_state FAR *state;
+    if (inflateStateCheck(strm)) return (unsigned long)-1;
+    state = (struct inflate_state FAR *)strm->state;
+    return (unsigned long)(state->next - state->codes);
+}
diff --git a/sys/lib/libz/inflate.h b/sys/lib/libz/inflate.h
index 07bd3e78a7c..a46cce6b6d0 100644
--- a/sys/lib/libz/inflate.h
+++ b/sys/lib/libz/inflate.h
@@ -1,5 +1,5 @@
 /* inflate.h -- internal inflate state definition
- * Copyright (C) 1995-2004 Mark Adler
+ * Copyright (C) 1995-2016 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -18,7 +18,7 @@
 
 /* Possible inflate modes between inflate() calls */
 typedef enum {
-    HEAD,       /* i: waiting for magic header */
+    HEAD = 16180,   /* i: waiting for magic header */
     FLAGS,      /* i: waiting for method and flags (gzip) */
     TIME,       /* i: waiting for modification time (gzip) */
     OS,         /* i: waiting for extra flags and operating system (gzip) */
@@ -32,11 +32,13 @@ typedef enum {
         TYPE,       /* i: waiting for type bits, including last-flag bit */
         TYPEDO,     /* i: same, but skip check to exit inflate on new block */
         STORED,     /* i: waiting for stored size (length and complement) */
+        COPY_,      /* i/o: same as COPY below, but only first time in */
         COPY,       /* i/o: waiting for input or output to copy stored block */
         TABLE,      /* i: waiting for dynamic block table lengths */
         LENLENS,    /* i: waiting for code length code lengths */
         CODELENS,   /* i: waiting for length/lit and distance code lengths */
-            LEN,        /* i: waiting for length/lit code */
+            LEN_,       /* i: same as LEN below, but only first time in */
+            LEN,        /* i: waiting for length/lit/eob code */
             LENEXT,     /* i: waiting for length extra bits */
             DIST,       /* i: waiting for distance code */
             DISTEXT,    /* i: waiting for distance extra bits */
@@ -53,19 +55,21 @@ typedef enum {
 /*
     State transitions between above modes -
 
-    (most modes can go to the BAD or MEM mode -- not shown for clarity)
+    (most modes can go to BAD or MEM on error -- not shown for clarity)
 
     Process header:
-        HEAD -> (gzip) or (zlib)
-        (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME
-        NAME -> COMMENT -> HCRC -> TYPE
+        HEAD -> (gzip) or (zlib) or (raw)
+        (gzip) -> FLAGS -> TIME -> OS -> EXLEN -> EXTRA -> NAME -> COMMENT ->
+                  HCRC -> TYPE
         (zlib) -> DICTID or TYPE
         DICTID -> DICT -> TYPE
+        (raw) -> TYPEDO
     Read deflate blocks:
-            TYPE -> STORED or TABLE or LEN or CHECK
-            STORED -> COPY -> TYPE
-            TABLE -> LENLENS -> CODELENS -> LEN
-    Read deflate codes:
+            TYPE -> TYPEDO -> STORED or TABLE or LEN_ or CHECK
+            STORED -> COPY_ -> COPY -> TYPE
+            TABLE -> LENLENS -> CODELENS -> LEN_
+            LEN_ -> LEN
+    Read deflate codes in fixed or dynamic block:
                 LEN -> LENEXT or LIT or TYPE
                 LENEXT -> DIST -> DISTEXT -> MATCH -> LEN
                 LIT -> LEN
@@ -73,11 +77,14 @@ typedef enum {
         CHECK -> LENGTH -> DONE
  */
 
-/* state maintained between inflate() calls.  Approximately 7K bytes. */
+/* State maintained between inflate() calls -- approximately 7K bytes, not
+   including the allocated sliding window, which is up to 32K bytes. */
 struct inflate_state {
+    z_streamp strm;             /* pointer back to this zlib stream */
     inflate_mode mode;          /* current inflate mode */
     int last;                   /* true if processing last block */
-    int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip */
+    int wrap;                   /* bit 0 true for zlib, bit 1 true for gzip,
+                                   bit 2 true to validate check value */
     int havedict;               /* true if dictionary provided */
     int flags;                  /* gzip header method and flags (0 if zlib) */
     unsigned dmax;              /* zlib header max distance (INFLATE_STRICT) */
@@ -88,7 +95,7 @@ struct inflate_state {
     unsigned wbits;             /* log base 2 of requested window size */
     unsigned wsize;             /* window size or zero if not using window */
     unsigned whave;             /* valid bytes in the window */
-    unsigned write;             /* window write index */
+    unsigned wnext;             /* window write index */
     unsigned char FAR *window;  /* allocated sliding window, if needed */
         /* bit accumulator */
     unsigned long hold;         /* input bit accumulator */
@@ -112,4 +119,7 @@ struct inflate_state {
     unsigned short lens[320];   /* temporary storage for code lengths */
     unsigned short work[288];   /* work area for code table building */
     code codes[ENOUGH];         /* space for code tables */
+    int sane;                   /* if false, allow invalid distance too far */
+    int back;                   /* bits back of last unprocessed length/lit */
+    unsigned was;               /* initial length of match */
 };
diff --git a/sys/lib/libz/inftrees.c b/sys/lib/libz/inftrees.c
index 053d66ac317..8553f2ade55 100644
--- a/sys/lib/libz/inftrees.c
+++ b/sys/lib/libz/inftrees.c
@@ -1,6 +1,6 @@
-/*	$OpenBSD: inftrees.c,v 1.15 2011/07/07 02:57:24 deraadt Exp $	*/
+/*	$OpenBSD: inftrees.c,v 1.16 2021/07/04 14:24:49 tb Exp $ */
 /* inftrees.c -- generate Huffman trees for efficient decoding
- * Copyright (C) 1995-2005 Mark Adler
+ * Copyright (C) 1995-2017 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -28,7 +28,7 @@
    table index bits.  It will differ if the request is greater than the
    longest code or if it is less than the shortest code.
  */
-int inflate_table(type, lens, codes, table, bits, work)
+int ZLIB_INTERNAL inflate_table(type, lens, codes, table, bits, work)
 codetype type;
 unsigned short FAR *lens;
 unsigned codes;
@@ -49,11 +49,11 @@ unsigned short FAR *work;
     unsigned fill;              /* index for replicating entries */
     unsigned low;               /* low bits for current root entry */
     unsigned mask;              /* mask for low root bits */
-    code this;                  /* table entry for duplication */
+    code here;                  /* table entry for duplication */
     code FAR *next;             /* next available space in table */
     const unsigned short FAR *base;     /* base value table to use */
     const unsigned short FAR *extra;    /* extra bits table to use */
-    int end;                    /* use base and extra for symbol > end */
+    unsigned match;             /* use base and extra for symbol >= match */
     unsigned short count[MAXBITS+1];    /* number of codes of each length */
     unsigned short offs[MAXBITS+1];     /* offsets in table for each length */
     static const unsigned short lbase[31] = { /* Length codes 257..285 base */
@@ -61,7 +61,7 @@ unsigned short FAR *work;
         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
     static const unsigned short lext[31] = { /* Length codes 257..285 extra */
         16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
-        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 201, 196};
+        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 77, 202};
     static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
@@ -114,15 +114,15 @@ unsigned short FAR *work;
         if (count[max] != 0) break;
     if (root > max) root = max;
     if (max == 0) {                     /* no symbols to code at all */
-        this.op = (unsigned char)64;    /* invalid code marker */
-        this.bits = (unsigned char)1;
-        this.val = (unsigned short)0;
-        *(*table)++ = this;             /* make a table to force an error */
-        *(*table)++ = this;
+        here.op = (unsigned char)64;    /* invalid code marker */
+        here.bits = (unsigned char)1;
+        here.val = (unsigned short)0;
+        *(*table)++ = here;             /* make a table to force an error */
+        *(*table)++ = here;
         *bits = 1;
         return 0;     /* no symbols, but wait for decoding to report error */
     }
-    for (min = 1; min <= MAXBITS; min++)
+    for (min = 1; min < max; min++)
         if (count[min] != 0) break;
     if (root < min) root = min;
 
@@ -165,11 +165,10 @@ unsigned short FAR *work;
        entered in the tables.
 
        used keeps track of how many table entries have been allocated from the
-       provided *table space.  It is checked when a LENS table is being made
-       against the space in *table, ENOUGH, minus the maximum space needed by
-       the worst case distance code, MAXD.  This should never happen, but the
-       sufficiency of ENOUGH has not been proven exhaustively, hence the check.
-       This assumes that when type == LENS, bits == 9.
+       provided *table space.  It is checked for LENS and DIST tables against
+       the constants ENOUGH_LENS and ENOUGH_DISTS to guard against changes in
+       the initial root table size constants.  See the comments in inftrees.h
+       for more information.
 
        sym increments through all symbols, and the loop terminates when
        all codes of length max, i.e. all codes, have been processed.  This
@@ -181,19 +180,17 @@ unsigned short FAR *work;
     switch (type) {
     case CODES:
         base = extra = work;    /* dummy value--not used */
-        end = 19;
+        match = 20;
         break;
     case LENS:
         base = lbase;
-        base -= 257;
         extra = lext;
-        extra -= 257;
-        end = 256;
+        match = 257;
         break;
-    default:            /* DISTS */
+    default:    /* DISTS */
         base = dbase;
         extra = dext;
-        end = -1;
+        match = 0;
     }
 
     /* initialize state for loop */
@@ -208,24 +205,25 @@ unsigned short FAR *work;
     mask = used - 1;            /* mask for comparing low */
 
     /* check available table space */
-    if (type == LENS && used >= ENOUGH - MAXD)
+    if ((type == LENS && used > ENOUGH_LENS) ||
+        (type == DISTS && used > ENOUGH_DISTS))
         return 1;
 
     /* process all codes and make table entries */
     for (;;) {
         /* create table entry */
-        this.bits = (unsigned char)(len - drop);
-        if ((int)(work[sym]) < end) {
-            this.op = (unsigned char)0;
-            this.val = work[sym];
+        here.bits = (unsigned char)(len - drop);
+        if (work[sym] + 1U < match) {
+            here.op = (unsigned char)0;
+            here.val = work[sym];
         }
-        else if ((int)(work[sym]) > end) {
-            this.op = (unsigned char)(extra[work[sym]]);
-            this.val = base[work[sym]];
+        else if (work[sym] >= match) {
+            here.op = (unsigned char)(extra[work[sym] - match]);
+            here.val = base[work[sym] - match];
         }
         else {
-            this.op = (unsigned char)(32 + 64);         /* end of block */
-            this.val = 0;
+            here.op = (unsigned char)(32 + 64);         /* end of block */
+            here.val = 0;
         }
 
         /* replicate for those indices with low len bits equal to huff */
@@ -234,7 +232,7 @@ unsigned short FAR *work;
         min = fill;                 /* save offset to next table */
         do {
             fill -= incr;
-            next[(huff >> drop) + fill] = this;
+            next[(huff >> drop) + fill] = here;
         } while (fill != 0);
 
         /* backwards increment the len-bit code huff */
@@ -276,7 +274,8 @@ unsigned short FAR *work;
 
             /* check for enough space */
             used += 1U << curr;
-            if (type == LENS && used >= ENOUGH - MAXD)
+            if ((type == LENS && used > ENOUGH_LENS) ||
+                (type == DISTS && used > ENOUGH_DISTS))
                 return 1;
 
             /* point entry in root table to sub-table */
@@ -287,38 +286,14 @@ unsigned short FAR *work;
         }
     }
 
-    /*
-       Fill in rest of table for incomplete codes.  This loop is similar to the
-       loop above in incrementing huff for table indices.  It is assumed that
-       len is equal to curr + drop, so there is no loop needed to increment
-       through high index bits.  When the current sub-table is filled, the loop
-       drops back to the root table to fill in any remaining entries there.
-     */
-    this.op = (unsigned char)64;                /* invalid code marker */
-    this.bits = (unsigned char)(len - drop);
-    this.val = (unsigned short)0;
-    while (huff != 0) {
-        /* when done with sub-table, drop back to root table */
-        if (drop != 0 && (huff & mask) != low) {
-            drop = 0;
-            len = root;
-            next = *table;
-            this.bits = (unsigned char)len;
-        }
-
-        /* put invalid code marker in table */
-        next[huff >> drop] = this;
-
-        /* backwards increment the len-bit code huff */
-        incr = 1U << (len - 1);
-        while (huff & incr)
-            incr >>= 1;
-        if (incr != 0) {
-            huff &= incr - 1;
-            huff += incr;
-        }
-        else
-            huff = 0;
+    /* fill in remaining table entry if code is incomplete (guaranteed to have
+       at most one remaining entry, since if the code is incomplete, the
+       maximum code length that was allowed to get this far is one bit) */
+    if (huff != 0) {
+        here.op = (unsigned char)64;            /* invalid code marker */
+        here.bits = (unsigned char)(len - drop);
+        here.val = (unsigned short)0;
+        next[huff] = here;
     }
 
     /* set return parameters */
diff --git a/sys/lib/libz/inftrees.h b/sys/lib/libz/inftrees.h
index cfd48b908d9..baa53a0b1a1 100644
--- a/sys/lib/libz/inftrees.h
+++ b/sys/lib/libz/inftrees.h
@@ -1,6 +1,5 @@
-/*	$OpenBSD: inftrees.h,v 1.8 2005/07/20 15:56:46 millert Exp $	*/
 /* inftrees.h -- header to use inftrees.c
- * Copyright (C) 1995-2005 Mark Adler
+ * Copyright (C) 1995-2005, 2010 Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -36,21 +35,28 @@ typedef struct {
     01000000 - invalid code
  */
 
-/* Maximum size of dynamic tree.  The maximum found in a long but non-
-   exhaustive search was 1444 code structures (852 for length/literals
-   and 592 for distances, the latter actually the result of an
-   exhaustive search).  The true maximum is not known, but the value
-   below is more than safe. */
-#define ENOUGH 2048
-#define MAXD 592
+/* Maximum size of the dynamic table.  The maximum number of code structures is
+   1444, which is the sum of 852 for literal/length codes and 592 for distance
+   codes.  These values were found by exhaustive searches using the program
+   examples/enough.c found in the zlib distribtution.  The arguments to that
+   program are the number of symbols, the initial root table size, and the
+   maximum bit length of a code.  "enough 286 9 15" for literal/length codes
+   returns returns 852, and "enough 30 6 15" for distance codes returns 592.
+   The initial root table size (9 or 6) is found in the fifth argument of the
+   inflate_table() calls in inflate.c and infback.c.  If the root table size is
+   changed, then these maximum sizes would be need to be recalculated and
+   updated. */
+#define ENOUGH_LENS 852
+#define ENOUGH_DISTS 592
+#define ENOUGH (ENOUGH_LENS+ENOUGH_DISTS)
 
-/* Type of code to build for inftable() */
+/* Type of code to build for inflate_table() */
 typedef enum {
     CODES,
     LENS,
     DISTS
 } codetype;
 
-extern int inflate_table OF((codetype type, unsigned short FAR *lens,
+int ZLIB_INTERNAL inflate_table OF((codetype type, unsigned short FAR *lens,
                              unsigned codes, code FAR * FAR *table,
                              unsigned FAR *bits, unsigned short FAR *work));
diff --git a/sys/lib/libz/trees.c b/sys/lib/libz/trees.c
index ac1c93718c9..23c1f6bee99 100644
--- a/sys/lib/libz/trees.c
+++ b/sys/lib/libz/trees.c
@@ -1,6 +1,7 @@
-/*	$OpenBSD: trees.c,v 1.3 2016/03/14 23:08:06 krw Exp $	*/
+/*	$OpenBSD: trees.c,v 1.4 2021/07/04 14:24:49 tb Exp $ */
 /* trees.c -- output deflated data using Huffman coding
- * Copyright (C) 1995-2005 Jean-loup Gailly
+ * Copyright (C) 1995-2017 Jean-loup Gailly
+ * detect_data_type() function provided freely by Cosmin Truta, 2006
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -30,12 +31,11 @@
  *          Addison-Wesley, 1983. ISBN 0-201-06672-6.
  */
 
-
 /* #define GEN_TREES_H */
 
 #include "deflate.h"
 
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
 #  include <ctype.h>
 #endif
 
@@ -73,11 +73,6 @@ local const uch bl_order[BL_CODES]
  * probability, to avoid transmitting the lengths for unused bit length codes.
  */
 
-#define Buf_size (8 * 2*sizeof(char))
-/* Number of bits used within bi_buf. (bi_buf might be implemented on
- * more than 16 bits on some systems.)
- */
-
 /* ===========================================================================
  * Local data. These are initialized only once.
  */
@@ -126,13 +121,13 @@ struct static_tree_desc_s {
     int     max_length;          /* max bit length for the codes */
 };
 
-local static_tree_desc  static_l_desc =
+local const static_tree_desc  static_l_desc =
 {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
 
-local static_tree_desc  static_d_desc =
+local const static_tree_desc  static_d_desc =
 {static_dtree, extra_dbits, 0,          D_CODES, MAX_BITS};
 
-local static_tree_desc  static_bl_desc =
+local const static_tree_desc  static_bl_desc =
 {(const ct_data *)0, extra_blbits, 0,   BL_CODES, MAX_BL_BITS};
 
 /* ===========================================================================
@@ -150,24 +145,22 @@ local void send_tree      OF((deflate_state *s, ct_data *tree, int max_code));
 local int  build_bl_tree  OF((deflate_state *s));
 local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
                               int blcodes));
-local void compress_block OF((deflate_state *s, ct_data *ltree,
-                              ct_data *dtree));
-local void set_data_type  OF((deflate_state *s));
+local void compress_block OF((deflate_state *s, const ct_data *ltree,
+                              const ct_data *dtree));
+local int  detect_data_type OF((deflate_state *s));
 local unsigned bi_reverse OF((unsigned value, int length));
 local void bi_windup      OF((deflate_state *s));
 local void bi_flush       OF((deflate_state *s));
-local void copy_block     OF((deflate_state *s, charf *buf, unsigned len,
-                              int header));
 
 #ifdef GEN_TREES_H
 local void gen_trees_header OF((void));
 #endif
 
-#ifndef DEBUG_LIBZ
+#ifndef ZLIB_DEBUG
 #  define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
    /* Send a code of the given tree. c and tree must not have side effects */
 
-#else /* DEBUG_LIBZ */
+#else /* !ZLIB_DEBUG */
 #  define send_code(s, c, tree) \
      { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
        send_bits(s, tree[c].Code, tree[c].Len); }
@@ -186,7 +179,7 @@ local void gen_trees_header OF((void));
  * Send a value on a given number of bits.
  * IN assertion: length <= 16 and value fits in length bits.
  */
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
 local void send_bits      OF((deflate_state *s, int value, int length));
 
 local void send_bits(s, value, length)
@@ -203,31 +196,31 @@ local void send_bits(s, value, length)
      * unused bits in value.
      */
     if (s->bi_valid > (int)Buf_size - length) {
-        s->bi_buf |= (value << s->bi_valid);
+        s->bi_buf |= (ush)value << s->bi_valid;
         put_short(s, s->bi_buf);
         s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
         s->bi_valid += length - Buf_size;
     } else {
-        s->bi_buf |= value << s->bi_valid;
+        s->bi_buf |= (ush)value << s->bi_valid;
         s->bi_valid += length;
     }
 }
-#else /* !DEBUG_LIBZ */
+#else /* !ZLIB_DEBUG */
 
 #define send_bits(s, value, length) \
 { int len = length;\
   if (s->bi_valid > (int)Buf_size - len) {\
-    int val = value;\
-    s->bi_buf |= (val << s->bi_valid);\
+    int val = (int)value;\
+    s->bi_buf |= (ush)val << s->bi_valid;\
     put_short(s, s->bi_buf);\
     s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
     s->bi_valid += len - Buf_size;\
   } else {\
-    s->bi_buf |= (value) << s->bi_valid;\
+    s->bi_buf |= (ush)(value) << s->bi_valid;\
     s->bi_valid += len;\
   }\
 }
-#endif /* DEBUG_LIBZ */
+#endif /* ZLIB_DEBUG */
 
 
 /* the arguments must not have side effects */
@@ -250,11 +243,13 @@ local void tr_static_init()
     if (static_init_done) return;
 
     /* For some embedded targets, global variables are not initialized: */
+#ifdef NO_INIT_GLOBAL_POINTERS
     static_l_desc.static_tree = static_ltree;
     static_l_desc.extra_bits = extra_lbits;
     static_d_desc.static_tree = static_dtree;
     static_d_desc.extra_bits = extra_dbits;
     static_bl_desc.extra_bits = extra_blbits;
+#endif
 
     /* Initialize the mapping length (0..255) -> length code (0..28) */
     length = 0;
@@ -319,7 +314,7 @@ local void tr_static_init()
  * Genererate the file trees.h describing the static trees.
  */
 #ifdef GEN_TREES_H
-#  ifndef DEBUG_LIBZ
+#  ifndef ZLIB_DEBUG
 #    include <stdio.h>
 #  endif
 
@@ -348,13 +343,14 @@ void gen_trees_header()
                 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
     }
 
-    fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n");
+    fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
     for (i = 0; i < DIST_CODE_LEN; i++) {
         fprintf(header, "%2u%s", _dist_code[i],
                 SEPARATOR(i, DIST_CODE_LEN-1, 20));
     }
 
-    fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
+    fprintf(header,
+        "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
     for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
         fprintf(header, "%2u%s", _length_code[i],
                 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
@@ -379,7 +375,7 @@ void gen_trees_header()
 /* ===========================================================================
  * Initialize the tree data structures for a new zlib stream.
  */
-void _tr_init(s)
+void ZLIB_INTERNAL _tr_init(s)
     deflate_state *s;
 {
     tr_static_init();
@@ -395,8 +391,7 @@ void _tr_init(s)
 
     s->bi_buf = 0;
     s->bi_valid = 0;
-    s->last_eob_len = 8; /* enough lookahead for inflate */
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
     s->compressed_len = 0L;
     s->bits_sent = 0L;
 #endif
@@ -524,12 +519,12 @@ local void gen_bitlen(s, desc)
         xbits = 0;
         if (n >= base) xbits = extra[n-base];
         f = tree[n].Freq;
-        s->opt_len += (ulg)f * (bits + xbits);
-        if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
+        s->opt_len += (ulg)f * (unsigned)(bits + xbits);
+        if (stree) s->static_len += (ulg)f * (unsigned)(stree[n].Len + xbits);
     }
     if (overflow == 0) return;
 
-    Trace((stderr,"\nbit length overflow\n"));
+    Tracev((stderr,"\nbit length overflow\n"));
     /* This happens for example on obj2 and pic of the Calgary corpus */
 
     /* Find the first bit length which could increase: */
@@ -556,9 +551,8 @@ local void gen_bitlen(s, desc)
             m = s->heap[--h];
             if (m > max_code) continue;
             if ((unsigned) tree[m].Len != (unsigned) bits) {
-                Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
-                s->opt_len += ((long)bits - (long)tree[m].Len)
-                              *(long)tree[m].Freq;
+                Tracev((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
+                s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq;
                 tree[m].Len = (ush)bits;
             }
             n--;
@@ -580,7 +574,7 @@ local void gen_codes (tree, max_code, bl_count)
     ushf *bl_count;            /* number of codes at each bit length */
 {
     ush next_code[MAX_BITS+1]; /* next code value for each bit length */
-    ush code = 0;              /* running code value */
+    unsigned code = 0;         /* running code value */
     int bits;                  /* bit index */
     int n;                     /* code index */
 
@@ -588,7 +582,8 @@ local void gen_codes (tree, max_code, bl_count)
      * without bit reversal.
      */
     for (bits = 1; bits <= MAX_BITS; bits++) {
-        next_code[bits] = code = (code + bl_count[bits-1]) << 1;
+        code = (code + bl_count[bits-1]) << 1;
+        next_code[bits] = (ush)code;
     }
     /* Check that the bit counts in bl_count are consistent. The last code
      * must be all ones.
@@ -601,7 +596,7 @@ local void gen_codes (tree, max_code, bl_count)
         int len = tree[n].Len;
         if (len == 0) continue;
         /* Now reverse the bits */
-        tree[n].Code = bi_reverse(next_code[len]++, len);
+        tree[n].Code = (ush)bi_reverse(next_code[len]++, len);
 
         Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
              n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
@@ -823,7 +818,7 @@ local int build_bl_tree(s)
         if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
     }
     /* Update opt_len to include the bit length tree and counts */
-    s->opt_len += 3*(max_blindex+1) + 5+5+4;
+    s->opt_len += 3*((ulg)max_blindex+1) + 5+5+4;
     Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
             s->opt_len, s->static_len));
 
@@ -864,65 +859,59 @@ local void send_all_trees(s, lcodes, dcodes, blcodes)
 /* ===========================================================================
  * Send a stored block
  */
-void _tr_stored_block(s, buf, stored_len, eof)
+void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
     deflate_state *s;
     charf *buf;       /* input block */
     ulg stored_len;   /* length of input block */
-    int eof;          /* true if this is the last block for a file */
+    int last;         /* one if this is the last block for a file */
 {
-    send_bits(s, (STORED_BLOCK<<1)+eof, 3);  /* send block type */
-#ifdef DEBUG_LIBZ
+    send_bits(s, (STORED_BLOCK<<1)+last, 3);    /* send block type */
+    bi_windup(s);        /* align on byte boundary */
+    put_short(s, (ush)stored_len);
+    put_short(s, (ush)~stored_len);
+    zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len);
+    s->pending += stored_len;
+#ifdef ZLIB_DEBUG
     s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
     s->compressed_len += (stored_len + 4) << 3;
+    s->bits_sent += 2*16;
+    s->bits_sent += stored_len<<3;
 #endif
-    copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
+}
+
+/* ===========================================================================
+ * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
+ */
+void ZLIB_INTERNAL _tr_flush_bits(s)
+    deflate_state *s;
+{
+    bi_flush(s);
 }
 
 /* ===========================================================================
  * Send one empty static block to give enough lookahead for inflate.
  * This takes 10 bits, of which 7 may remain in the bit buffer.
- * The current inflate code requires 9 bits of lookahead. If the
- * last two codes for the previous block (real code plus EOB) were coded
- * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
- * the last real code. In this case we send two empty static blocks instead
- * of one. (There are no problems if the previous block is stored or fixed.)
- * To simplify the code, we assume the worst case of last real code encoded
- * on one bit only.
  */
-void _tr_align(s)
+void ZLIB_INTERNAL _tr_align(s)
     deflate_state *s;
 {
     send_bits(s, STATIC_TREES<<1, 3);
     send_code(s, END_BLOCK, static_ltree);
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
     s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
 #endif
     bi_flush(s);
-    /* Of the 10 bits for the empty block, we have already sent
-     * (10 - bi_valid) bits. The lookahead for the last real code (before
-     * the EOB of the previous block) was thus at least one plus the length
-     * of the EOB plus what we have just sent of the empty static block.
-     */
-    if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
-        send_bits(s, STATIC_TREES<<1, 3);
-        send_code(s, END_BLOCK, static_ltree);
-#ifdef DEBUG_LIBZ
-        s->compressed_len += 10L;
-#endif
-        bi_flush(s);
-    }
-    s->last_eob_len = 7;
 }
 
 /* ===========================================================================
  * Determine the best encoding for the current block: dynamic trees, static
- * trees or store, and output the encoded block to the zip file.
+ * trees or store, and write out the encoded block.
  */
-void _tr_flush_block(s, buf, stored_len, eof)
+void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
     deflate_state *s;
     charf *buf;       /* input block, or NULL if too old */
     ulg stored_len;   /* length of input block */
-    int eof;          /* true if this is the last block for a file */
+    int last;         /* one if this is the last block for a file */
 {
     ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
     int max_blindex = 0;  /* index of last bit length code of non zero freq */
@@ -931,8 +920,8 @@ void _tr_flush_block(s, buf, stored_len, eof)
     if (s->level > 0) {
 
         /* Check if the file is binary or text */
-        if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN)
-            set_data_type(s);
+        if (s->strm->data_type == Z_UNKNOWN)
+            s->strm->data_type = detect_data_type(s);
 
         /* Construct the literal and distance trees */
         build_tree(s, (tree_desc *)(&(s->l_desc)));
@@ -962,14 +951,14 @@ void _tr_flush_block(s, buf, stored_len, eof)
         if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
 
     } else {
-        Assert(buf != NULL, "lost buf");
+        Assert(buf != (char*)0, "lost buf");
         opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
     }
 
 #ifdef FORCE_STORED
-    if (buf != NULL) { /* force stored block */
+    if (buf != (char*)0) { /* force stored block */
 #else
-    if (stored_len+4 <= opt_lenb && buf != NULL) {
+    if (stored_len+4 <= opt_lenb && buf != (char*)0) {
                        /* 4: two words for the lengths */
 #endif
         /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
@@ -978,24 +967,26 @@ void _tr_flush_block(s, buf, stored_len, eof)
          * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
          * transform a block into a stored block.
          */
-        _tr_stored_block(s, buf, stored_len, eof);
+        _tr_stored_block(s, buf, stored_len, last);
 
 #ifdef FORCE_STATIC
     } else if (static_lenb >= 0) { /* force static trees */
 #else
     } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
 #endif
-        send_bits(s, (STATIC_TREES<<1)+eof, 3);
-        compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
-#ifdef DEBUG_LIBZ
+        send_bits(s, (STATIC_TREES<<1)+last, 3);
+        compress_block(s, (const ct_data *)static_ltree,
+                       (const ct_data *)static_dtree);
+#ifdef ZLIB_DEBUG
         s->compressed_len += 3 + s->static_len;
 #endif
     } else {
-        send_bits(s, (DYN_TREES<<1)+eof, 3);
+        send_bits(s, (DYN_TREES<<1)+last, 3);
         send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
                        max_blindex+1);
-        compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
-#ifdef DEBUG_LIBZ
+        compress_block(s, (const ct_data *)s->dyn_ltree,
+                       (const ct_data *)s->dyn_dtree);
+#ifdef ZLIB_DEBUG
         s->compressed_len += 3 + s->opt_len;
 #endif
     }
@@ -1005,21 +996,21 @@ void _tr_flush_block(s, buf, stored_len, eof)
      */
     init_block(s);
 
-    if (eof) {
+    if (last) {
         bi_windup(s);
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
         s->compressed_len += 7;  /* align on byte boundary */
 #endif
     }
     Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
-           s->compressed_len-7*eof));
+           s->compressed_len-7*last));
 }
 
 /* ===========================================================================
  * Save the match info and tally the frequency counts. Return true if
  * the current block must be flushed.
  */
-int _tr_tally (s, dist, lc)
+int ZLIB_INTERNAL _tr_tally (s, dist, lc)
     deflate_state *s;
     unsigned dist;  /* distance of matched string */
     unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */
@@ -1071,8 +1062,8 @@ int _tr_tally (s, dist, lc)
  */
 local void compress_block(s, ltree, dtree)
     deflate_state *s;
-    ct_data *ltree; /* literal tree */
-    ct_data *dtree; /* distance tree */
+    const ct_data *ltree; /* literal tree */
+    const ct_data *dtree; /* distance tree */
 {
     unsigned dist;      /* distance of matched string */
     int lc;             /* match length or unmatched char (if dist == 0) */
@@ -1102,7 +1093,7 @@ local void compress_block(s, ltree, dtree)
             send_code(s, code, dtree);       /* send the distance code */
             extra = extra_dbits[code];
             if (extra != 0) {
-                dist -= base_dist[code];
+                dist -= (unsigned)base_dist[code];
                 send_bits(s, dist, extra);   /* send the extra distance bits */
             }
         } /* literal or match pair ? */
@@ -1114,28 +1105,48 @@ local void compress_block(s, ltree, dtree)
     } while (lx < s->last_lit);
 
     send_code(s, END_BLOCK, ltree);
-    s->last_eob_len = ltree[END_BLOCK].Len;
 }
 
 /* ===========================================================================
- * Set the data type to BINARY or TEXT, using a crude approximation:
- * set it to Z_TEXT if all symbols are either printable characters (33 to 255)
- * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise.
+ * Check if the data type is TEXT or BINARY, using the following algorithm:
+ * - TEXT if the two conditions below are satisfied:
+ *    a) There are no non-portable control characters belonging to the
+ *       "black list" (0..6, 14..25, 28..31).
+ *    b) There is at least one printable character belonging to the
+ *       "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
+ * - BINARY otherwise.
+ * - The following partially-portable control characters form a
+ *   "gray list" that is ignored in this detection algorithm:
+ *   (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
  * IN assertion: the fields Freq of dyn_ltree are set.
  */
-local void set_data_type(s)
+local int detect_data_type(s)
     deflate_state *s;
 {
+    /* black_mask is the bit mask of black-listed bytes
+     * set bits 0..6, 14..25, and 28..31
+     * 0xf3ffc07f = binary 11110011111111111100000001111111
+     */
+    unsigned long black_mask = 0xf3ffc07fUL;
     int n;
 
-    for (n = 0; n < 9; n++)
+    /* Check for non-textual ("black-listed") bytes. */
+    for (n = 0; n <= 31; n++, black_mask >>= 1)
+        if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
+            return Z_BINARY;
+
+    /* Check for textual ("white-listed") bytes. */
+    if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
+            || s->dyn_ltree[13].Freq != 0)
+        return Z_TEXT;
+    for (n = 32; n < LITERALS; n++)
         if (s->dyn_ltree[n].Freq != 0)
-            break;
-    if (n == 9)
-        for (n = 14; n < 32; n++)
-            if (s->dyn_ltree[n].Freq != 0)
-                break;
-    s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY;
+            return Z_TEXT;
+
+    /* There are no "black-listed" or "white-listed" bytes:
+     * this stream either is empty or has tolerated ("gray-listed") bytes only.
+     */
+    return Z_BINARY;
 }
 
 /* ===========================================================================
@@ -1185,35 +1196,7 @@ local void bi_windup(s)
     }
     s->bi_buf = 0;
     s->bi_valid = 0;
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
     s->bits_sent = (s->bits_sent+7) & ~7;
 #endif
 }
-
-/* ===========================================================================
- * Copy a stored block, storing first the length and its
- * one's complement if requested.
- */
-local void copy_block(s, buf, len, header)
-    deflate_state *s;
-    charf    *buf;    /* the input data */
-    unsigned len;     /* its length */
-    int      header;  /* true if block header must be written */
-{
-    bi_windup(s);        /* align on byte boundary */
-    s->last_eob_len = 8; /* enough lookahead for inflate */
-
-    if (header) {
-        put_short(s, (ush)len);
-        put_short(s, (ush)~len);
-#ifdef DEBUG_LIBZ
-        s->bits_sent += 2*16;
-#endif
-    }
-#ifdef DEBUG_LIBZ
-    s->bits_sent += (ulg)len<<3;
-#endif
-    while (len--) {
-        put_byte(s, *buf++);
-    }
-}
diff --git a/sys/lib/libz/trees.h b/sys/lib/libz/trees.h
index 05f597670dc..d35639d82a2 100644
--- a/sys/lib/libz/trees.h
+++ b/sys/lib/libz/trees.h
@@ -1,4 +1,3 @@
-/*	$OpenBSD: trees.h,v 1.1 2011/07/07 02:57:24 deraadt Exp $	*/
 /* header created automatically with -DGEN_TREES_H */
 
 local const ct_data static_ltree[L_CODES+2] = {
@@ -71,7 +70,7 @@ local const ct_data static_dtree[D_CODES] = {
 {{19},{ 5}}, {{11},{ 5}}, {{27},{ 5}}, {{ 7},{ 5}}, {{23},{ 5}}
 };
 
-const uch _dist_code[DIST_CODE_LEN] = {
+const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {
  0,  1,  2,  3,  4,  4,  5,  5,  6,  6,  6,  6,  7,  7,  7,  7,  8,  8,  8,  8,
  8,  8,  8,  8,  9,  9,  9,  9,  9,  9,  9,  9, 10, 10, 10, 10, 10, 10, 10, 10,
 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
@@ -100,7 +99,7 @@ const uch _dist_code[DIST_CODE_LEN] = {
 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29
 };
 
-const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {
+const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {
  0,  1,  2,  3,  4,  5,  6,  7,  8,  8,  9,  9, 10, 10, 11, 11, 12, 12, 12, 12,
 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16,
 17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19,
diff --git a/sys/lib/libz/zconf.h b/sys/lib/libz/zconf.h
index 5d269e197b6..d25bdcc6279 100644
--- a/sys/lib/libz/zconf.h
+++ b/sys/lib/libz/zconf.h
@@ -1,62 +1,166 @@
-/*	$OpenBSD: zconf.h,v 1.12 2019/05/12 15:56:56 jca Exp $	*/
 /* zconf.h -- configuration of the zlib compression library
- * Copyright (C) 1995-2005 Jean-loup Gailly.
+ * Copyright (C) 1995-2016 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
-
 #ifndef ZCONF_H
 #define ZCONF_H
 
 /*
  * If you *really* need a unique prefix for all types and library functions,
  * compile with -DZ_PREFIX. The "standard" zlib should be compiled without it.
+ * Even better than compiling with -DZ_PREFIX would be to use configure to set
+ * this permanently in zconf.h using "./configure --zprefix".
  */
-#ifdef Z_PREFIX
-#  define deflateInit_          z_deflateInit_
+#ifdef Z_PREFIX     /* may be set to #if 1 by ./configure */
+#  define Z_PREFIX_SET
+
+/* all linked symbols and init macros */
+#  define _dist_code            z__dist_code
+#  define _length_code          z__length_code
+#  define _tr_align             z__tr_align
+#  define _tr_flush_bits        z__tr_flush_bits
+#  define _tr_flush_block       z__tr_flush_block
+#  define _tr_init              z__tr_init
+#  define _tr_stored_block      z__tr_stored_block
+#  define _tr_tally             z__tr_tally
+#  define adler32               z_adler32
+#  define adler32_combine       z_adler32_combine
+#  define adler32_combine64     z_adler32_combine64
+#  define adler32_z             z_adler32_z
+#  ifndef Z_SOLO
+#    define compress              z_compress
+#    define compress2             z_compress2
+#    define compressBound         z_compressBound
+#  endif
+#  define crc32                 z_crc32
+#  define crc32_combine         z_crc32_combine
+#  define crc32_combine64       z_crc32_combine64
+#  define crc32_z               z_crc32_z
 #  define deflate               z_deflate
+#  define deflateBound          z_deflateBound
+#  define deflateCopy           z_deflateCopy
 #  define deflateEnd            z_deflateEnd
-#  define inflateInit_          z_inflateInit_
-#  define inflate               z_inflate
-#  define inflateEnd            z_inflateEnd
+#  define deflateGetDictionary  z_deflateGetDictionary
+#  define deflateInit           z_deflateInit
+#  define deflateInit2          z_deflateInit2
 #  define deflateInit2_         z_deflateInit2_
-#  define deflateSetDictionary  z_deflateSetDictionary
-#  define deflateCopy           z_deflateCopy
-#  define deflateReset          z_deflateReset
+#  define deflateInit_          z_deflateInit_
 #  define deflateParams         z_deflateParams
-#  define deflateBound          z_deflateBound
+#  define deflatePending        z_deflatePending
 #  define deflatePrime          z_deflatePrime
+#  define deflateReset          z_deflateReset
+#  define deflateResetKeep      z_deflateResetKeep
+#  define deflateSetDictionary  z_deflateSetDictionary
+#  define deflateSetHeader      z_deflateSetHeader
+#  define deflateTune           z_deflateTune
+#  define deflate_copyright     z_deflate_copyright
+#  define get_crc_table         z_get_crc_table
+#  ifndef Z_SOLO
+#    define gz_error              z_gz_error
+#    define gz_intmax             z_gz_intmax
+#    define gz_strwinerror        z_gz_strwinerror
+#    define gzbuffer              z_gzbuffer
+#    define gzclearerr            z_gzclearerr
+#    define gzclose               z_gzclose
+#    define gzclose_r             z_gzclose_r
+#    define gzclose_w             z_gzclose_w
+#    define gzdirect              z_gzdirect
+#    define gzdopen               z_gzdopen
+#    define gzeof                 z_gzeof
+#    define gzerror               z_gzerror
+#    define gzflush               z_gzflush
+#    define gzfread               z_gzfread
+#    define gzfwrite              z_gzfwrite
+#    define gzgetc                z_gzgetc
+#    define gzgetc_               z_gzgetc_
+#    define gzgets                z_gzgets
+#    define gzoffset              z_gzoffset
+#    define gzoffset64            z_gzoffset64
+#    define gzopen                z_gzopen
+#    define gzopen64              z_gzopen64
+#    ifdef _WIN32
+#      define gzopen_w              z_gzopen_w
+#    endif
+#    define gzprintf              z_gzprintf
+#    define gzputc                z_gzputc
+#    define gzputs                z_gzputs
+#    define gzread                z_gzread
+#    define gzrewind              z_gzrewind
+#    define gzseek                z_gzseek
+#    define gzseek64              z_gzseek64
+#    define gzsetparams           z_gzsetparams
+#    define gztell                z_gztell
+#    define gztell64              z_gztell64
+#    define gzungetc              z_gzungetc
+#    define gzvprintf             z_gzvprintf
+#    define gzwrite               z_gzwrite
+#  endif
+#  define inflate               z_inflate
+#  define inflateBack           z_inflateBack
+#  define inflateBackEnd        z_inflateBackEnd
+#  define inflateBackInit       z_inflateBackInit
+#  define inflateBackInit_      z_inflateBackInit_
+#  define inflateCodesUsed      z_inflateCodesUsed
+#  define inflateCopy           z_inflateCopy
+#  define inflateEnd            z_inflateEnd
+#  define inflateGetDictionary  z_inflateGetDictionary
+#  define inflateGetHeader      z_inflateGetHeader
+#  define inflateInit           z_inflateInit
+#  define inflateInit2          z_inflateInit2
 #  define inflateInit2_         z_inflateInit2_
+#  define inflateInit_          z_inflateInit_
+#  define inflateMark           z_inflateMark
+#  define inflatePrime          z_inflatePrime
+#  define inflateReset          z_inflateReset
+#  define inflateReset2         z_inflateReset2
+#  define inflateResetKeep      z_inflateResetKeep
 #  define inflateSetDictionary  z_inflateSetDictionary
 #  define inflateSync           z_inflateSync
 #  define inflateSyncPoint      z_inflateSyncPoint
-#  define inflateCopy           z_inflateCopy
-#  define inflateReset          z_inflateReset
-#  define inflateBack           z_inflateBack
-#  define inflateBackEnd        z_inflateBackEnd
-#  define compress              z_compress
-#  define compress2             z_compress2
-#  define compressBound         z_compressBound
-#  define uncompress            z_uncompress
-#  define adler32               z_adler32
-#  define crc32                 z_crc32
-#  define get_crc_table         z_get_crc_table
+#  define inflateUndermine      z_inflateUndermine
+#  define inflateValidate       z_inflateValidate
+#  define inflate_copyright     z_inflate_copyright
+#  define inflate_fast          z_inflate_fast
+#  define inflate_table         z_inflate_table
+#  ifndef Z_SOLO
+#    define uncompress            z_uncompress
+#    define uncompress2           z_uncompress2
+#  endif
 #  define zError                z_zError
+#  ifndef Z_SOLO
+#    define zcalloc               z_zcalloc
+#    define zcfree                z_zcfree
+#  endif
+#  define zlibCompileFlags      z_zlibCompileFlags
+#  define zlibVersion           z_zlibVersion
 
+/* all zlib typedefs in zlib.h and zconf.h */
+#  define Byte                  z_Byte
+#  define Bytef                 z_Bytef
 #  define alloc_func            z_alloc_func
+#  define charf                 z_charf
 #  define free_func             z_free_func
+#  ifndef Z_SOLO
+#    define gzFile                z_gzFile
+#  endif
+#  define gz_header             z_gz_header
+#  define gz_headerp            z_gz_headerp
 #  define in_func               z_in_func
+#  define intf                  z_intf
 #  define out_func              z_out_func
-#  define Byte                  z_Byte
 #  define uInt                  z_uInt
-#  define uLong                 z_uLong
-#  define Bytef                 z_Bytef
-#  define charf                 z_charf
-#  define intf                  z_intf
 #  define uIntf                 z_uIntf
+#  define uLong                 z_uLong
 #  define uLongf                z_uLongf
-#  define voidpf                z_voidpf
 #  define voidp                 z_voidp
+#  define voidpc                z_voidpc
+#  define voidpf                z_voidpf
+
+/* all zlib structs in zlib.h and zconf.h */
+#  define gz_header_s           z_gz_header_s
+#  define internal_state        z_internal_state
+
 #endif
 
 #if defined(__MSDOS__) && !defined(MSDOS)
@@ -131,9 +235,19 @@
 #  define z_const
 #endif
 
-/* Some Mac compilers merge all .h files incorrectly: */
-#if defined(__MWERKS__)||defined(applec)||defined(THINK_C)||defined(__SC__)
-#  define NO_DUMMY_DECL
+#ifdef Z_SOLO
+   typedef unsigned long z_size_t;
+#else
+#  define z_longlong long long
+#  if defined(NO_SIZE_T)
+     typedef unsigned NO_SIZE_T z_size_t;
+#  elif defined(STDC)
+#    include <sys/types.h>
+     typedef size_t z_size_t;
+#  else
+     typedef unsigned long z_size_t;
+#  endif
+#  undef z_longlong
 #endif
 
 /* Maximum value for memLevel in deflateInit2 */
@@ -163,7 +277,7 @@
  Of course this will generally degrade compression (there's no free lunch).
 
    The memory requirements for inflate are (in bytes) 1 << windowBits
- that is, 32K for windowBits=15 (default value) plus a few kilobytes
+ that is, 32K for windowBits=15 (default value) plus about 7 kilobytes
  for small objects.
 */
 
@@ -177,6 +291,14 @@
 #  endif
 #endif
 
+#ifndef Z_ARG /* function prototypes for stdarg */
+#  if defined(STDC) || defined(Z_HAVE_STDARG_H)
+#    define Z_ARG(args)  args
+#  else
+#    define Z_ARG(args)  ()
+#  endif
+#endif
+
 /* The following definitions for FAR are needed only for MSDOS mixed
  * model programming (small or medium model with some far allocations).
  * This was tested only with MSC; for other MSDOS compilers you may have
@@ -290,41 +412,125 @@ typedef uLong FAR uLongf;
    typedef Byte       *voidp;
 #endif
 
-#include <sys/types.h> /* for off_t */
-#include <sys/unistd.h> /* for SEEK_* and off_t */
-#define z_off_t  off_t
-#ifndef SEEK_SET
+#if !defined(Z_U4) && !defined(Z_SOLO) && defined(STDC)
+#  include <sys/limits.h>
+#  if (UINT_MAX == 0xffffffffUL)
+#    define Z_U4 unsigned
+#  elif (ULONG_MAX == 0xffffffffUL)
+#    define Z_U4 unsigned long
+#  elif (USHRT_MAX == 0xffffffffUL)
+#    define Z_U4 unsigned short
+#  endif
+#endif
+
+#ifdef Z_U4
+   typedef Z_U4 z_crc_t;
+#else
+   typedef unsigned long z_crc_t;
+#endif
+
+#ifdef _KERNEL
+#  define Z_HAVE_UNISTD_H
+#endif
+
+#ifdef HAVE_UNISTD_H    /* may be set to #if 1 by ./configure */
+#  define Z_HAVE_UNISTD_H
+#endif
+
+#ifdef HAVE_STDARG_H    /* may be set to #if 1 by ./configure */
+#  define Z_HAVE_STDARG_H
+#endif
+
+#ifdef STDC
+#  ifndef Z_SOLO
+#    include <sys/types.h>      /* for off_t */
+#  endif
+#endif
+
+#if defined(STDC) || defined(Z_HAVE_STDARG_H)
+#  ifndef Z_SOLO
+#    include <sys/stdarg.h>         /* for va_list */
+#  endif
+#endif
+
+#ifdef _WIN32
+#  ifndef Z_SOLO
+#    include <stddef.h>         /* for wchar_t */
+#  endif
+#endif
+
+/* a little trick to accommodate both "#define _LARGEFILE64_SOURCE" and
+ * "#define _LARGEFILE64_SOURCE 1" as requesting 64-bit operations, (even
+ * though the former does not conform to the LFS document), but considering
+ * both "#undef _LARGEFILE64_SOURCE" and "#define _LARGEFILE64_SOURCE 0" as
+ * equivalently requesting no 64-bit operations
+ */
+#if defined(_LARGEFILE64_SOURCE) && -_LARGEFILE64_SOURCE - -1 == 1
+#  undef _LARGEFILE64_SOURCE
+#endif
+
+#if defined(__WATCOMC__) && !defined(Z_HAVE_UNISTD_H)
+#  define Z_HAVE_UNISTD_H
+#endif
+#ifndef Z_SOLO
+#  if defined(Z_HAVE_UNISTD_H) || defined(_LARGEFILE64_SOURCE)
+#    include <sys/unistd.h>         /* for SEEK_*, off_t, and _LFS64_LARGEFILE */
+#    ifdef VMS
+#      include <unixio.h>       /* for off_t */
+#    endif
+#    ifndef z_off_t
+#      define z_off_t off_t
+#    endif
+#  endif
+#endif
+
+#if defined(_LFS64_LARGEFILE) && _LFS64_LARGEFILE-0
+#  define Z_LFS64
+#endif
+
+#if defined(_LARGEFILE64_SOURCE) && defined(Z_LFS64)
+#  define Z_LARGE64
+#endif
+
+#if defined(_FILE_OFFSET_BITS) && _FILE_OFFSET_BITS-0 == 64 && defined(Z_LFS64)
+#  define Z_WANT64
+#endif
+
+#if !defined(SEEK_SET) && !defined(Z_SOLO)
 #  define SEEK_SET        0       /* Seek from beginning of file.  */
 #  define SEEK_CUR        1       /* Seek from current position.  */
 #  define SEEK_END        2       /* Set file pointer to EOF plus "offset" */
 #endif
 
-#if defined(__OS400__)
-#define NO_vsnprintf
+#ifndef z_off_t
+#  define z_off_t long
 #endif
 
-#if defined(__MVS__)
-#  define NO_vsnprintf
-#  ifdef FAR
-#    undef FAR
+#if !defined(_WIN32) && defined(Z_LARGE64)
+#  define z_off64_t off64_t
+#else
+#  if defined(_WIN32) && !defined(__GNUC__) && !defined(Z_SOLO)
+#    define z_off64_t __int64
+#  else
+#    define z_off64_t z_off_t
 #  endif
 #endif
 
 /* MVS linker does not support external names larger than 8 bytes */
 #if defined(__MVS__)
-#   pragma map(deflateInit_,"DEIN")
-#   pragma map(deflateInit2_,"DEIN2")
-#   pragma map(deflateEnd,"DEEND")
-#   pragma map(deflateBound,"DEBND")
-#   pragma map(inflateInit_,"ININ")
-#   pragma map(inflateInit2_,"ININ2")
-#   pragma map(inflateEnd,"INEND")
-#   pragma map(inflateSync,"INSY")
-#   pragma map(inflateSetDictionary,"INSEDI")
-#   pragma map(compressBound,"CMBND")
-#   pragma map(inflate_table,"INTABL")
-#   pragma map(inflate_fast,"INFA")
-#   pragma map(inflate_copyright,"INCOPY")
+  #pragma map(deflateInit_,"DEIN")
+  #pragma map(deflateInit2_,"DEIN2")
+  #pragma map(deflateEnd,"DEEND")
+  #pragma map(deflateBound,"DEBND")
+  #pragma map(inflateInit_,"ININ")
+  #pragma map(inflateInit2_,"ININ2")
+  #pragma map(inflateEnd,"INEND")
+  #pragma map(inflateSync,"INSY")
+  #pragma map(inflateSetDictionary,"INSEDI")
+  #pragma map(compressBound,"CMBND")
+  #pragma map(inflate_table,"INTABL")
+  #pragma map(inflate_fast,"INFA")
+  #pragma map(inflate_copyright,"INCOPY")
 #endif
 
 #endif /* ZCONF_H */
diff --git a/sys/lib/libz/zlib.h b/sys/lib/libz/zlib.h
index a2c23f08b76..f3d6cb6c05e 100644
--- a/sys/lib/libz/zlib.h
+++ b/sys/lib/libz/zlib.h
@@ -1,8 +1,7 @@
-/*	$OpenBSD: zlib.h,v 1.11 2019/05/12 15:56:56 jca Exp $	*/
 /* zlib.h -- interface of the 'zlib' general purpose compression library
-  version 1.2.3, July 18th, 2005
+  version 1.2.11, January 15th, 2017
 
-  Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
+  Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -25,8 +24,8 @@
 
 
   The data format used by the zlib library is described by RFCs (Request for
-  Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
-  (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
+  Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
+  (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
 */
 
 #ifndef ZLIB_H
@@ -38,41 +37,45 @@
 extern "C" {
 #endif
 
-#define ZLIB_VERSION "1.2.3"
-#define ZLIB_VERNUM 0x1230
+#define ZLIB_VERSION "1.2.11"
+#define ZLIB_VERNUM 0x12b0
+#define ZLIB_VER_MAJOR 1
+#define ZLIB_VER_MINOR 2
+#define ZLIB_VER_REVISION 11
+#define ZLIB_VER_SUBREVISION 0
 
 /*
-     The 'zlib' compression library provides in-memory compression and
-  decompression functions, including integrity checks of the uncompressed
-  data.  This version of the library supports only one compression method
-  (deflation) but other algorithms will be added later and will have the same
-  stream interface.
-
-     Compression can be done in a single step if the buffers are large
-  enough (for example if an input file is mmap'ed), or can be done by
-  repeated calls of the compression function.  In the latter case, the
-  application must provide more input and/or consume the output
+    The 'zlib' compression library provides in-memory compression and
+  decompression functions, including integrity checks of the uncompressed data.
+  This version of the library supports only one compression method (deflation)
+  but other algorithms will be added later and will have the same stream
+  interface.
+
+    Compression can be done in a single step if the buffers are large enough,
+  or can be done by repeated calls of the compression function.  In the latter
+  case, the application must provide more input and/or consume the output
   (providing more output space) before each call.
 
-     The compressed data format used by default by the in-memory functions is
+    The compressed data format used by default by the in-memory functions is
   the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
   around a deflate stream, which is itself documented in RFC 1951.
 
-     The library also supports reading and writing files in gzip (.gz) format
+    The library also supports reading and writing files in gzip (.gz) format
   with an interface similar to that of stdio using the functions that start
   with "gz".  The gzip format is different from the zlib format.  gzip is a
   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
 
-     This library can optionally read and write gzip streams in memory as well.
+    This library can optionally read and write gzip and raw deflate streams in
+  memory as well.
 
-     The zlib format was designed to be compact and fast for use in memory
+    The zlib format was designed to be compact and fast for use in memory
   and on communications channels.  The gzip format was designed for single-
   file compression on file systems, has a larger header than zlib to maintain
   directory information, and uses a different, slower check method than zlib.
 
-     The library does not install any signal handler. The decoder checks
-  the consistency of the compressed data, so the library should never
-  crash even in case of corrupted input.
+    The library does not install any signal handler.  The decoder checks
+  the consistency of the compressed data, so the library should never crash
+  even in the case of corrupted input.
 */
 
 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
@@ -83,11 +86,11 @@ struct internal_state;
 typedef struct z_stream_s {
     z_const Bytef *next_in;     /* next input byte */
     uInt     avail_in;  /* number of bytes available at next_in */
-    z_off_t  total_in;  /* total nb of input bytes read so far */
+    z_off_t  total_in;  /* total number of input bytes read so far */
 
-    Bytef    *next_out; /* next output byte should be put there */
+    Bytef    *next_out; /* next output byte will go here */
     uInt     avail_out; /* remaining free space at next_out */
-    z_off_t  total_out; /* total nb of bytes output so far */
+    z_off_t  total_out; /* total number of bytes output so far */
 
     z_const char *msg;  /* last error message, NULL if no error */
     struct internal_state FAR *state; /* not visible by applications */
@@ -96,8 +99,9 @@ typedef struct z_stream_s {
     free_func  zfree;   /* used to free the internal state */
     voidpf     opaque;  /* private data object passed to zalloc and zfree */
 
-    int     data_type;  /* best guess about the data type: binary or text */
-    uLong   adler;      /* adler32 value of the uncompressed data */
+    int     data_type;  /* best guess about the data type: binary or text
+                           for deflate, or the decoding state for inflate */
+    uLong   adler;      /* Adler-32 or CRC-32 value of the uncompressed data */
     uLong   reserved;   /* reserved for future use */
 } z_stream;
 
@@ -127,45 +131,47 @@ typedef struct gz_header_s {
 typedef gz_header FAR *gz_headerp;
 
 /*
-   The application must update next_in and avail_in when avail_in has
-   dropped to zero. It must update next_out and avail_out when avail_out
-   has dropped to zero. The application must initialize zalloc, zfree and
-   opaque before calling the init function. All other fields are set by the
-   compression library and must not be updated by the application.
-
-   The opaque value provided by the application will be passed as the first
-   parameter for calls of zalloc and zfree. This can be useful for custom
-   memory management. The compression library attaches no meaning to the
+     The application must update next_in and avail_in when avail_in has dropped
+   to zero.  It must update next_out and avail_out when avail_out has dropped
+   to zero.  The application must initialize zalloc, zfree and opaque before
+   calling the init function.  All other fields are set by the compression
+   library and must not be updated by the application.
+
+     The opaque value provided by the application will be passed as the first
+   parameter for calls of zalloc and zfree.  This can be useful for custom
+   memory management.  The compression library attaches no meaning to the
    opaque value.
 
-   zalloc must return Z_NULL if there is not enough memory for the object.
+     zalloc must return Z_NULL if there is not enough memory for the object.
    If zlib is used in a multi-threaded application, zalloc and zfree must be
-   thread safe.
-
-   On 16-bit systems, the functions zalloc and zfree must be able to allocate
-   exactly 65536 bytes, but will not be required to allocate more than this
-   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
-   pointers returned by zalloc for objects of exactly 65536 bytes *must*
-   have their offset normalized to zero. The default allocation function
-   provided by this library ensures this (see zutil.c). To reduce memory
-   requirements and avoid any allocation of 64K objects, at the expense of
-   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
-
-   The fields total_in and total_out can be used for statistics or
-   progress reports. After compression, total_in holds the total size of
-   the uncompressed data and may be saved for use in the decompressor
-   (particularly if the decompressor wants to decompress everything in
-   a single step).
+   thread safe.  In that case, zlib is thread-safe.  When zalloc and zfree are
+   Z_NULL on entry to the initialization function, they are set to internal
+   routines that use the standard library functions malloc() and free().
+
+     On 16-bit systems, the functions zalloc and zfree must be able to allocate
+   exactly 65536 bytes, but will not be required to allocate more than this if
+   the symbol MAXSEG_64K is defined (see zconf.h).  WARNING: On MSDOS, pointers
+   returned by zalloc for objects of exactly 65536 bytes *must* have their
+   offset normalized to zero.  The default allocation function provided by this
+   library ensures this (see zutil.c).  To reduce memory requirements and avoid
+   any allocation of 64K objects, at the expense of compression ratio, compile
+   the library with -DMAX_WBITS=14 (see zconf.h).
+
+     The fields total_in and total_out can be used for statistics or progress
+   reports.  After compression, total_in holds the total size of the
+   uncompressed data and may be saved for use by the decompressor (particularly
+   if the decompressor wants to decompress everything in a single step).
 */
 
                         /* constants */
 
 #define Z_NO_FLUSH      0
-#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
+#define Z_PARTIAL_FLUSH 1
 #define Z_SYNC_FLUSH    2
 #define Z_FULL_FLUSH    3
 #define Z_FINISH        4
 #define Z_BLOCK         5
+#define Z_TREES         6
 /* Allowed flush values; see deflate() and inflate() below for details */
 
 #define Z_OK            0
@@ -177,8 +183,8 @@ typedef gz_header FAR *gz_headerp;
 #define Z_MEM_ERROR    (-4)
 #define Z_BUF_ERROR    (-5)
 #define Z_VERSION_ERROR (-6)
-/* Return codes for the compression/decompression functions. Negative
- * values are errors, positive values are used for special but normal events.
+/* Return codes for the compression/decompression functions. Negative values
+ * are errors, positive values are used for special but normal events.
  */
 
 #define Z_NO_COMPRESSION         0
@@ -198,7 +204,7 @@ typedef gz_header FAR *gz_headerp;
 #define Z_TEXT     1
 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
 #define Z_UNKNOWN  2
-/* Possible values of the data_type field (though see inflate()) */
+/* Possible values of the data_type field for deflate() */
 
 #define Z_DEFLATED   8
 /* The deflate compression method (the only one supported in this version) */
@@ -208,67 +214,70 @@ typedef gz_header FAR *gz_headerp;
 #define zlib_version zlibVersion()
 /* for compatibility with versions < 1.0.2 */
 
+
                         /* basic functions */
 
 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
-   If the first character differs, the library code actually used is
-   not compatible with the zlib.h header file used by the application.
-   This check is automatically made by deflateInit and inflateInit.
+   If the first character differs, the library code actually used is not
+   compatible with the zlib.h header file used by the application.  This check
+   is automatically made by deflateInit and inflateInit.
  */
 
 /*
 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
 
-     Initializes the internal stream state for compression. The fields
-   zalloc, zfree and opaque must be initialized before by the caller.
-   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
-   use default allocation functions.
+     Initializes the internal stream state for compression.  The fields
+   zalloc, zfree and opaque must be initialized before by the caller.  If
+   zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
+   allocation functions.
 
      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
-   1 gives best speed, 9 gives best compression, 0 gives no compression at
-   all (the input data is simply copied a block at a time).
-   Z_DEFAULT_COMPRESSION requests a default compromise between speed and
-   compression (currently equivalent to level 6).
+   1 gives best speed, 9 gives best compression, 0 gives no compression at all
+   (the input data is simply copied a block at a time).  Z_DEFAULT_COMPRESSION
+   requests a default compromise between speed and compression (currently
+   equivalent to level 6).
 
-     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
-   enough memory, Z_STREAM_ERROR if level is not a valid compression level,
+     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
+   memory, Z_STREAM_ERROR if level is not a valid compression level, or
    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
-   with the version assumed by the caller (ZLIB_VERSION).
-   msg is set to null if there is no error message.  deflateInit does not
-   perform any compression: this will be done by deflate().
+   with the version assumed by the caller (ZLIB_VERSION).  msg is set to null
+   if there is no error message.  deflateInit does not perform any compression:
+   this will be done by deflate().
 */
 
 
 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
 /*
     deflate compresses as much data as possible, and stops when the input
-  buffer becomes empty or the output buffer becomes full. It may introduce some
-  output latency (reading input without producing any output) except when
+  buffer becomes empty or the output buffer becomes full.  It may introduce
+  some output latency (reading input without producing any output) except when
   forced to flush.
 
-    The detailed semantics are as follows. deflate performs one or both of the
+    The detailed semantics are as follows.  deflate performs one or both of the
   following actions:
 
   - Compress more input starting at next_in and update next_in and avail_in
-    accordingly. If not all input can be processed (because there is not
+    accordingly.  If not all input can be processed (because there is not
     enough room in the output buffer), next_in and avail_in are updated and
     processing will resume at this point for the next call of deflate().
 
-  - Provide more output starting at next_out and update next_out and avail_out
-    accordingly. This action is forced if the parameter flush is non zero.
+  - Generate more output starting at next_out and update next_out and avail_out
+    accordingly.  This action is forced if the parameter flush is non zero.
     Forcing flush frequently degrades the compression ratio, so this parameter
-    should be set only when necessary (in interactive applications).
-    Some output may be provided even if flush is not set.
-
-  Before the call of deflate(), the application should ensure that at least
-  one of the actions is possible, by providing more input and/or consuming
-  more output, and updating avail_in or avail_out accordingly; avail_out
-  should never be zero before the call. The application can consume the
-  compressed output when it wants, for example when the output buffer is full
-  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
-  and with zero avail_out, it must be called again after making room in the
-  output buffer because there might be more output pending.
+    should be set only when necessary.  Some output may be provided even if
+    flush is zero.
+
+    Before the call of deflate(), the application should ensure that at least
+  one of the actions is possible, by providing more input and/or consuming more
+  output, and updating avail_in or avail_out accordingly; avail_out should
+  never be zero before the call.  The application can consume the compressed
+  output when it wants, for example when the output buffer is full (avail_out
+  == 0), or after each call of deflate().  If deflate returns Z_OK and with
+  zero avail_out, it must be called again after making room in the output
+  buffer because there might be more output pending. See deflatePending(),
+  which can be used if desired to determine whether or not there is more ouput
+  in that case.
 
     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
   decide how much data to accumulate before producing output, in order to
@@ -276,66 +285,91 @@ ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
 
     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
   flushed to the output buffer and the output is aligned on a byte boundary, so
-  that the decompressor can get all input data available so far. (In particular
-  avail_in is zero after the call if enough output space has been provided
-  before the call.)  Flushing may degrade compression for some compression
-  algorithms and so it should be used only when necessary.
+  that the decompressor can get all input data available so far.  (In
+  particular avail_in is zero after the call if enough output space has been
+  provided before the call.) Flushing may degrade compression for some
+  compression algorithms and so it should be used only when necessary.  This
+  completes the current deflate block and follows it with an empty stored block
+  that is three bits plus filler bits to the next byte, followed by four bytes
+  (00 00 ff ff).
+
+    If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
+  output buffer, but the output is not aligned to a byte boundary.  All of the
+  input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
+  This completes the current deflate block and follows it with an empty fixed
+  codes block that is 10 bits long.  This assures that enough bytes are output
+  in order for the decompressor to finish the block before the empty fixed
+  codes block.
+
+    If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
+  for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
+  seven bits of the current block are held to be written as the next byte after
+  the next deflate block is completed.  In this case, the decompressor may not
+  be provided enough bits at this point in order to complete decompression of
+  the data provided so far to the compressor.  It may need to wait for the next
+  block to be emitted.  This is for advanced applications that need to control
+  the emission of deflate blocks.
 
     If flush is set to Z_FULL_FLUSH, all output is flushed as with
   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
   restart from this point if previous compressed data has been damaged or if
-  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
+  random access is desired.  Using Z_FULL_FLUSH too often can seriously degrade
   compression.
 
     If deflate returns with avail_out == 0, this function must be called again
   with the same value of the flush parameter and more output space (updated
   avail_out), until the flush is complete (deflate returns with non-zero
-  avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
+  avail_out).  In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
   avail_out is greater than six to avoid repeated flush markers due to
   avail_out == 0 on return.
 
     If the parameter flush is set to Z_FINISH, pending input is processed,
-  pending output is flushed and deflate returns with Z_STREAM_END if there
-  was enough output space; if deflate returns with Z_OK, this function must be
-  called again with Z_FINISH and more output space (updated avail_out) but no
-  more input data, until it returns with Z_STREAM_END or an error. After
-  deflate has returned Z_STREAM_END, the only possible operations on the
-  stream are deflateReset or deflateEnd.
-
-    Z_FINISH can be used immediately after deflateInit if all the compression
-  is to be done in a single step. In this case, avail_out must be at least
-  the value returned by deflateBound (see below). If deflate does not return
-  Z_STREAM_END, then it must be called again as described above.
-
-    deflate() sets strm->adler to the adler32 checksum of all input read
-  so far (that is, total_in bytes).
+  pending output is flushed and deflate returns with Z_STREAM_END if there was
+  enough output space.  If deflate returns with Z_OK or Z_BUF_ERROR, this
+  function must be called again with Z_FINISH and more output space (updated
+  avail_out) but no more input data, until it returns with Z_STREAM_END or an
+  error.  After deflate has returned Z_STREAM_END, the only possible operations
+  on the stream are deflateReset or deflateEnd.
+
+    Z_FINISH can be used in the first deflate call after deflateInit if all the
+  compression is to be done in a single step.  In order to complete in one
+  call, avail_out must be at least the value returned by deflateBound (see
+  below).  Then deflate is guaranteed to return Z_STREAM_END.  If not enough
+  output space is provided, deflate will not return Z_STREAM_END, and it must
+  be called again as described above.
+
+    deflate() sets strm->adler to the Adler-32 checksum of all input read
+  so far (that is, total_in bytes).  If a gzip stream is being generated, then
+  strm->adler will be the CRC-32 checksum of the input read so far.  (See
+  deflateInit2 below.)
 
     deflate() may update strm->data_type if it can make a good guess about
-  the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
-  binary. This field is only for information purposes and does not affect
-  the compression algorithm in any manner.
+  the input data type (Z_BINARY or Z_TEXT).  If in doubt, the data is
+  considered binary.  This field is only for information purposes and does not
+  affect the compression algorithm in any manner.
 
     deflate() returns Z_OK if some progress has been made (more input
   processed or more output produced), Z_STREAM_END if all input has been
   consumed and all output has been produced (only when flush is set to
   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
-  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
-  (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
-  fatal, and deflate() can be called again with more input and more output
-  space to continue compressing.
+  if next_in or next_out was Z_NULL or the state was inadvertently written over
+  by the application), or Z_BUF_ERROR if no progress is possible (for example
+  avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not fatal, and
+  deflate() can be called again with more input and more output space to
+  continue compressing.
 */
 
 
 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
 /*
      All dynamically allocated data structures for this stream are freed.
-   This function discards any unprocessed input and does not flush any
-   pending output.
+   This function discards any unprocessed input and does not flush any pending
+   output.
 
      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
-   prematurely (some input or output was discarded). In the error case,
-   msg may be set but then points to a static string (which must not be
+   prematurely (some input or output was discarded).  In the error case, msg
+   may be set but then points to a static string (which must not be
    deallocated).
 */
 
@@ -343,134 +377,157 @@ ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
 /*
 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
 
-     Initializes the internal stream state for decompression. The fields
+     Initializes the internal stream state for decompression.  The fields
    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
-   the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
-   value depends on the compression method), inflateInit determines the
-   compression method from the zlib header and allocates all data structures
-   accordingly; otherwise the allocation will be deferred to the first call of
-   inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
-   use default allocation functions.
+   the caller.  In the current version of inflate, the provided input is not
+   read or consumed.  The allocation of a sliding window will be deferred to
+   the first call of inflate (if the decompression does not complete on the
+   first call).  If zalloc and zfree are set to Z_NULL, inflateInit updates
+   them to use default allocation functions.
 
      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
-   version assumed by the caller.  msg is set to null if there is no error
-   message. inflateInit does not perform any decompression apart from reading
-   the zlib header if present: this will be done by inflate().  (So next_in and
-   avail_in may be modified, but next_out and avail_out are unchanged.)
+   version assumed by the caller, or Z_STREAM_ERROR if the parameters are
+   invalid, such as a null pointer to the structure.  msg is set to null if
+   there is no error message.  inflateInit does not perform any decompression.
+   Actual decompression will be done by inflate().  So next_in, and avail_in,
+   next_out, and avail_out are unused and unchanged.  The current
+   implementation of inflateInit() does not process any header information --
+   that is deferred until inflate() is called.
 */
 
 
 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
 /*
     inflate decompresses as much data as possible, and stops when the input
-  buffer becomes empty or the output buffer becomes full. It may introduce
+  buffer becomes empty or the output buffer becomes full.  It may introduce
   some output latency (reading input without producing any output) except when
   forced to flush.
 
-  The detailed semantics are as follows. inflate performs one or both of the
+  The detailed semantics are as follows.  inflate performs one or both of the
   following actions:
 
   - Decompress more input starting at next_in and update next_in and avail_in
-    accordingly. If not all input can be processed (because there is not
-    enough room in the output buffer), next_in is updated and processing
-    will resume at this point for the next call of inflate().
-
-  - Provide more output starting at next_out and update next_out and avail_out
-    accordingly.  inflate() provides as much output as possible, until there
-    is no more input data or no more space in the output buffer (see below
-    about the flush parameter).
-
-  Before the call of inflate(), the application should ensure that at least
-  one of the actions is possible, by providing more input and/or consuming
-  more output, and updating the next_* and avail_* values accordingly.
-  The application can consume the uncompressed output when it wants, for
-  example when the output buffer is full (avail_out == 0), or after each
-  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
-  must be called again after making room in the output buffer because there
-  might be more output pending.
-
-    The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
-  Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
-  output as possible to the output buffer. Z_BLOCK requests that inflate() stop
-  if and when it gets to the next deflate block boundary. When decoding the
-  zlib or gzip format, this will cause inflate() to return immediately after
-  the header and before the first block. When doing a raw inflate, inflate()
-  will go ahead and process the first block, and will return when it gets to
-  the end of that block, or when it runs out of data.
+    accordingly.  If not all input can be processed (because there is not
+    enough room in the output buffer), then next_in and avail_in are updated
+    accordingly, and processing will resume at this point for the next call of
+    inflate().
+
+  - Generate more output starting at next_out and update next_out and avail_out
+    accordingly.  inflate() provides as much output as possible, until there is
+    no more input data or no more space in the output buffer (see below about
+    the flush parameter).
+
+    Before the call of inflate(), the application should ensure that at least
+  one of the actions is possible, by providing more input and/or consuming more
+  output, and updating the next_* and avail_* values accordingly.  If the
+  caller of inflate() does not provide both available input and available
+  output space, it is possible that there will be no progress made.  The
+  application can consume the uncompressed output when it wants, for example
+  when the output buffer is full (avail_out == 0), or after each call of
+  inflate().  If inflate returns Z_OK and with zero avail_out, it must be
+  called again after making room in the output buffer because there might be
+  more output pending.
+
+    The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
+  Z_BLOCK, or Z_TREES.  Z_SYNC_FLUSH requests that inflate() flush as much
+  output as possible to the output buffer.  Z_BLOCK requests that inflate()
+  stop if and when it gets to the next deflate block boundary.  When decoding
+  the zlib or gzip format, this will cause inflate() to return immediately
+  after the header and before the first block.  When doing a raw inflate,
+  inflate() will go ahead and process the first block, and will return when it
+  gets to the end of that block, or when it runs out of data.
 
     The Z_BLOCK option assists in appending to or combining deflate streams.
-  Also to assist in this, on return inflate() will set strm->data_type to the
-  number of unused bits in the last byte taken from strm->next_in, plus 64
-  if inflate() is currently decoding the last block in the deflate stream,
-  plus 128 if inflate() returned immediately after decoding an end-of-block
-  code or decoding the complete header up to just before the first byte of the
-  deflate stream. The end-of-block will not be indicated until all of the
-  uncompressed data from that block has been written to strm->next_out.  The
-  number of unused bits may in general be greater than seven, except when
-  bit 7 of data_type is set, in which case the number of unused bits will be
-  less than eight.
+  To assist in this, on return inflate() always sets strm->data_type to the
+  number of unused bits in the last byte taken from strm->next_in, plus 64 if
+  inflate() is currently decoding the last block in the deflate stream, plus
+  128 if inflate() returned immediately after decoding an end-of-block code or
+  decoding the complete header up to just before the first byte of the deflate
+  stream.  The end-of-block will not be indicated until all of the uncompressed
+  data from that block has been written to strm->next_out.  The number of
+  unused bits may in general be greater than seven, except when bit 7 of
+  data_type is set, in which case the number of unused bits will be less than
+  eight.  data_type is set as noted here every time inflate() returns for all
+  flush options, and so can be used to determine the amount of currently
+  consumed input in bits.
+
+    The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
+  end of each deflate block header is reached, before any actual data in that
+  block is decoded.  This allows the caller to determine the length of the
+  deflate block header for later use in random access within a deflate block.
+  256 is added to the value of strm->data_type when inflate() returns
+  immediately after reaching the end of the deflate block header.
 
     inflate() should normally be called until it returns Z_STREAM_END or an
-  error. However if all decompression is to be performed in a single step
-  (a single call of inflate), the parameter flush should be set to
-  Z_FINISH. In this case all pending input is processed and all pending
-  output is flushed; avail_out must be large enough to hold all the
-  uncompressed data. (The size of the uncompressed data may have been saved
-  by the compressor for this purpose.) The next operation on this stream must
-  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
-  is never required, but can be used to inform inflate that a faster approach
-  may be used for the single inflate() call.
+  error.  However if all decompression is to be performed in a single step (a
+  single call of inflate), the parameter flush should be set to Z_FINISH.  In
+  this case all pending input is processed and all pending output is flushed;
+  avail_out must be large enough to hold all of the uncompressed data for the
+  operation to complete.  (The size of the uncompressed data may have been
+  saved by the compressor for this purpose.)  The use of Z_FINISH is not
+  required to perform an inflation in one step.  However it may be used to
+  inform inflate that a faster approach can be used for the single inflate()
+  call.  Z_FINISH also informs inflate to not maintain a sliding window if the
+  stream completes, which reduces inflate's memory footprint.  If the stream
+  does not complete, either because not all of the stream is provided or not
+  enough output space is provided, then a sliding window will be allocated and
+  inflate() can be called again to continue the operation as if Z_NO_FLUSH had
+  been used.
 
      In this implementation, inflate() always flushes as much output as
   possible to the output buffer, and always uses the faster approach on the
-  first call. So the only effect of the flush parameter in this implementation
-  is on the return value of inflate(), as noted below, or when it returns early
-  because Z_BLOCK is used.
+  first call.  So the effects of the flush parameter in this implementation are
+  on the return value of inflate() as noted below, when inflate() returns early
+  when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
+  memory for a sliding window when Z_FINISH is used.
 
      If a preset dictionary is needed after this call (see inflateSetDictionary
-  below), inflate sets strm->adler to the adler32 checksum of the dictionary
+  below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
-  strm->adler to the adler32 checksum of all output produced so far (that is,
+  strm->adler to the Adler-32 checksum of all output produced so far (that is,
   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
-  below. At the end of the stream, inflate() checks that its computed adler32
+  below.  At the end of the stream, inflate() checks that its computed Adler-32
   checksum is equal to that saved by the compressor and returns Z_STREAM_END
   only if the checksum is correct.
 
-    inflate() will decompress and check either zlib-wrapped or gzip-wrapped
-  deflate data.  The header type is detected automatically.  Any information
-  contained in the gzip header is not retained, so applications that need that
-  information should instead use raw inflate, see inflateInit2() below, or
-  inflateBack() and perform their own processing of the gzip header and
-  trailer.
+    inflate() can decompress and check either zlib-wrapped or gzip-wrapped
+  deflate data.  The header type is detected automatically, if requested when
+  initializing with inflateInit2().  Any information contained in the gzip
+  header is not retained unless inflateGetHeader() is used.  When processing
+  gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
+  produced so far.  The CRC-32 is checked against the gzip trailer, as is the
+  uncompressed length, modulo 2^32.
 
     inflate() returns Z_OK if some progress has been made (more input processed
   or more output produced), Z_STREAM_END if the end of the compressed data has
   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
   corrupted (input stream not conforming to the zlib format or incorrect check
-  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
-  if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
-  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
-  output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
+  value, in which case strm->msg points to a string with a more specific
+  error), Z_STREAM_ERROR if the stream structure was inconsistent (for example
+  next_in or next_out was Z_NULL, or the state was inadvertently written over
+  by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR
+  if no progress was possible or if there was not enough room in the output
+  buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
   inflate() can be called again with more input and more output space to
-  continue decompressing. If Z_DATA_ERROR is returned, the application may then
-  call inflateSync() to look for a good compression block if a partial recovery
-  of the data is desired.
+  continue decompressing.  If Z_DATA_ERROR is returned, the application may
+  then call inflateSync() to look for a good compression block if a partial
+  recovery of the data is to be attempted.
 */
 
 
 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
 /*
      All dynamically allocated data structures for this stream are freed.
-   This function discards any unprocessed input and does not flush any
-   pending output.
+   This function discards any unprocessed input and does not flush any pending
+   output.
 
-     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
-   was inconsistent. In the error case, msg may be set but then points to a
-   static string (which must not be deallocated).
+     inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state
+   was inconsistent.
 */
 
+
                         /* Advanced functions */
 
 /*
@@ -485,55 +542,70 @@ ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
                                      int  memLevel,
                                      int  strategy));
 
-     This is another version of deflateInit with more compression options. The
-   fields next_in, zalloc, zfree and opaque must be initialized before by
-   the caller.
+     This is another version of deflateInit with more compression options.  The
+   fields next_in, zalloc, zfree and opaque must be initialized before by the
+   caller.
 
-     The method parameter is the compression method. It must be Z_DEFLATED in
+     The method parameter is the compression method.  It must be Z_DEFLATED in
    this version of the library.
 
      The windowBits parameter is the base two logarithm of the window size
-   (the size of the history buffer). It should be in the range 8..15 for this
-   version of the library. Larger values of this parameter result in better
-   compression at the expense of memory usage. The default value is 15 if
+   (the size of the history buffer).  It should be in the range 8..15 for this
+   version of the library.  Larger values of this parameter result in better
+   compression at the expense of memory usage.  The default value is 15 if
    deflateInit is used instead.
 
-     windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
-   determines the window size. deflate() will then generate raw deflate data
-   with no zlib header or trailer, and will not compute an adler32 check value.
+     For the current implementation of deflate(), a windowBits value of 8 (a
+   window size of 256 bytes) is not supported.  As a result, a request for 8
+   will result in 9 (a 512-byte window).  In that case, providing 8 to
+   inflateInit2() will result in an error when the zlib header with 9 is
+   checked against the initialization of inflate().  The remedy is to not use 8
+   with deflateInit2() with this initialization, or at least in that case use 9
+   with inflateInit2().
 
-     windowBits can also be greater than 15 for optional gzip encoding. Add
+     windowBits can also be -8..-15 for raw deflate.  In this case, -windowBits
+   determines the window size.  deflate() will then generate raw deflate data
+   with no zlib header or trailer, and will not compute a check value.
+
+     windowBits can also be greater than 15 for optional gzip encoding.  Add
    16 to windowBits to write a simple gzip header and trailer around the
-   compressed data instead of a zlib wrapper. The gzip header will have no
-   file name, no extra data, no comment, no modification time (set to zero),
-   no header crc, and the operating system will be set to 255 (unknown).  If a
-   gzip stream is being written, strm->adler is a crc32 instead of an adler32.
+   compressed data instead of a zlib wrapper.  The gzip header will have no
+   file name, no extra data, no comment, no modification time (set to zero), no
+   header crc, and the operating system will be set to the appropriate value,
+   if the operating system was determined at compile time.  If a gzip stream is
+   being written, strm->adler is a CRC-32 instead of an Adler-32.
+
+     For raw deflate or gzip encoding, a request for a 256-byte window is
+   rejected as invalid, since only the zlib header provides a means of
+   transmitting the window size to the decompressor.
 
      The memLevel parameter specifies how much memory should be allocated
-   for the internal compression state. memLevel=1 uses minimum memory but
-   is slow and reduces compression ratio; memLevel=9 uses maximum memory
-   for optimal speed. The default value is 8. See zconf.h for total memory
-   usage as a function of windowBits and memLevel.
+   for the internal compression state.  memLevel=1 uses minimum memory but is
+   slow and reduces compression ratio; memLevel=9 uses maximum memory for
+   optimal speed.  The default value is 8.  See zconf.h for total memory usage
+   as a function of windowBits and memLevel.
 
-     The strategy parameter is used to tune the compression algorithm. Use the
+     The strategy parameter is used to tune the compression algorithm.  Use the
    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
    filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
    string match), or Z_RLE to limit match distances to one (run-length
-   encoding). Filtered data consists mostly of small values with a somewhat
-   random distribution. In this case, the compression algorithm is tuned to
-   compress them better. The effect of Z_FILTERED is to force more Huffman
+   encoding).  Filtered data consists mostly of small values with a somewhat
+   random distribution.  In this case, the compression algorithm is tuned to
+   compress them better.  The effect of Z_FILTERED is to force more Huffman
    coding and less string matching; it is somewhat intermediate between
-   Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
-   Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
-   parameter only affects the compression ratio but not the correctness of the
-   compressed output even if it is not set appropriately.  Z_FIXED prevents the
-   use of dynamic Huffman codes, allowing for a simpler decoder for special
-   applications.
-
-      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
-   memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
-   method). msg is set to null if there is no error message.  deflateInit2 does
-   not perform any compression: this will be done by deflate().
+   Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.  Z_RLE is designed to be almost as
+   fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data.  The
+   strategy parameter only affects the compression ratio but not the
+   correctness of the compressed output even if it is not set appropriately.
+   Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
+   decoder for special applications.
+
+     deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
+   memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
+   method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
+   incompatible with the version assumed by the caller (ZLIB_VERSION).  msg is
+   set to null if there is no error message.  deflateInit2 does not perform any
+   compression: this will be done by deflate().
 */
 
 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
@@ -541,38 +613,65 @@ ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
                                              uInt  dictLength));
 /*
      Initializes the compression dictionary from the given byte sequence
-   without producing any compressed output. This function must be called
-   immediately after deflateInit, deflateInit2 or deflateReset, before any
-   call of deflate. The compressor and decompressor must use exactly the same
-   dictionary (see inflateSetDictionary).
+   without producing any compressed output.  When using the zlib format, this
+   function must be called immediately after deflateInit, deflateInit2 or
+   deflateReset, and before any call of deflate.  When doing raw deflate, this
+   function must be called either before any call of deflate, or immediately
+   after the completion of a deflate block, i.e. after all input has been
+   consumed and all output has been delivered when using any of the flush
+   options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH.  The
+   compressor and decompressor must use exactly the same dictionary (see
+   inflateSetDictionary).
 
      The dictionary should consist of strings (byte sequences) that are likely
    to be encountered later in the data to be compressed, with the most commonly
-   used strings preferably put towards the end of the dictionary. Using a
+   used strings preferably put towards the end of the dictionary.  Using a
    dictionary is most useful when the data to be compressed is short and can be
    predicted with good accuracy; the data can then be compressed better than
    with the default empty dictionary.
 
      Depending on the size of the compression data structures selected by
    deflateInit or deflateInit2, a part of the dictionary may in effect be
-   discarded, for example if the dictionary is larger than the window size in
-   deflate or deflate2. Thus the strings most likely to be useful should be
-   put at the end of the dictionary, not at the front. In addition, the
-   current implementation of deflate will use at most the window size minus
-   262 bytes of the provided dictionary.
+   discarded, for example if the dictionary is larger than the window size
+   provided in deflateInit or deflateInit2.  Thus the strings most likely to be
+   useful should be put at the end of the dictionary, not at the front.  In
+   addition, the current implementation of deflate will use at most the window
+   size minus 262 bytes of the provided dictionary.
 
-     Upon return of this function, strm->adler is set to the adler32 value
+     Upon return of this function, strm->adler is set to the Adler-32 value
    of the dictionary; the decompressor may later use this value to determine
-   which dictionary has been used by the compressor. (The adler32 value
+   which dictionary has been used by the compressor.  (The Adler-32 value
    applies to the whole dictionary even if only a subset of the dictionary is
    actually used by the compressor.) If a raw deflate was requested, then the
-   adler32 value is not computed and strm->adler is not set.
+   Adler-32 value is not computed and strm->adler is not set.
 
      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
-   parameter is invalid (such as NULL dictionary) or the stream state is
+   parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
    inconsistent (for example if deflate has already been called for this stream
-   or if the compression method is bsort). deflateSetDictionary does not
-   perform any compression: this will be done by deflate().
+   or if not at a block boundary for raw deflate).  deflateSetDictionary does
+   not perform any compression: this will be done by deflate().
+*/
+
+ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm,
+                                             Bytef *dictionary,
+                                             uInt  *dictLength));
+/*
+     Returns the sliding dictionary being maintained by deflate.  dictLength is
+   set to the number of bytes in the dictionary, and that many bytes are copied
+   to dictionary.  dictionary must have enough space, where 32768 bytes is
+   always enough.  If deflateGetDictionary() is called with dictionary equal to
+   Z_NULL, then only the dictionary length is returned, and nothing is copied.
+   Similary, if dictLength is Z_NULL, then it is not set.
+
+     deflateGetDictionary() may return a length less than the window size, even
+   when more than the window size in input has been provided. It may return up
+   to 258 bytes less in that case, due to how zlib's implementation of deflate
+   manages the sliding window and lookahead for matches, where matches can be
+   up to 258 bytes long. If the application needs the last window-size bytes of
+   input, then that would need to be saved by the application outside of zlib.
+
+     deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
+   stream state is inconsistent.
 */
 
 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
@@ -582,26 +681,26 @@ ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
 
      This function can be useful when several compression strategies will be
    tried, for example when there are several ways of pre-processing the input
-   data with a filter. The streams that will be discarded should then be freed
+   data with a filter.  The streams that will be discarded should then be freed
    by calling deflateEnd.  Note that deflateCopy duplicates the internal
-   compression state which can be quite large, so this strategy is slow and
-   can consume lots of memory.
+   compression state which can be quite large, so this strategy is slow and can
+   consume lots of memory.
 
      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
-   (such as zalloc being NULL). msg is left unchanged in both source and
+   (such as zalloc being Z_NULL).  msg is left unchanged in both source and
    destination.
 */
 
 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
 /*
-     This function is equivalent to deflateEnd followed by deflateInit,
-   but does not free and reallocate all the internal compression state.
-   The stream will keep the same compression level and any other attributes
-   that may have been set by deflateInit2.
+     This function is equivalent to deflateEnd followed by deflateInit, but
+   does not free and reallocate the internal compression state.  The stream
+   will leave the compression level and any other attributes that may have been
+   set unchanged.
 
-      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
-   stream state was inconsistent (such as zalloc or state being NULL).
+     deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
+   stream state was inconsistent (such as zalloc or state being Z_NULL).
 */
 
 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
@@ -609,20 +708,36 @@ ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
                                       int strategy));
 /*
      Dynamically update the compression level and compression strategy.  The
-   interpretation of level and strategy is as in deflateInit2.  This can be
+   interpretation of level and strategy is as in deflateInit2().  This can be
    used to switch between compression and straight copy of the input data, or
-   to switch to a different kind of input data requiring a different
-   strategy. If the compression level is changed, the input available so far
-   is compressed with the old level (and may be flushed); the new level will
-   take effect only at the next call of deflate().
-
-     Before the call of deflateParams, the stream state must be set as for
-   a call of deflate(), since the currently available input may have to
-   be compressed and flushed. In particular, strm->avail_out must be non-zero.
-
-     deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
-   stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
-   if strm->avail_out was zero.
+   to switch to a different kind of input data requiring a different strategy.
+   If the compression approach (which is a function of the level) or the
+   strategy is changed, and if any input has been consumed in a previous
+   deflate() call, then the input available so far is compressed with the old
+   level and strategy using deflate(strm, Z_BLOCK).  There are three approaches
+   for the compression levels 0, 1..3, and 4..9 respectively.  The new level
+   and strategy will take effect at the next call of deflate().
+
+     If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
+   not have enough output space to complete, then the parameter change will not
+   take effect.  In this case, deflateParams() can be called again with the
+   same parameters and more output space to try again.
+
+     In order to assure a change in the parameters on the first try, the
+   deflate stream should be flushed using deflate() with Z_BLOCK or other flush
+   request until strm.avail_out is not zero, before calling deflateParams().
+   Then no more input data should be provided before the deflateParams() call.
+   If this is done, the old level and strategy will be applied to the data
+   compressed before deflateParams(), and the new level and strategy will be
+   applied to the the data compressed after deflateParams().
+
+     deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream
+   state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
+   there was not enough output space to complete the compression of the
+   available input data before a change in the strategy or approach.  Note that
+   in the case of a Z_BUF_ERROR, the parameters are not changed.  A return
+   value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be
+   retried with more output space.
 */
 
 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
@@ -646,31 +761,53 @@ ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
                                        uLong sourceLen));
 /*
      deflateBound() returns an upper bound on the compressed size after
-   deflation of sourceLen bytes.  It must be called after deflateInit()
-   or deflateInit2().  This would be used to allocate an output buffer
-   for deflation in a single pass, and so would be called before deflate().
+   deflation of sourceLen bytes.  It must be called after deflateInit() or
+   deflateInit2(), and after deflateSetHeader(), if used.  This would be used
+   to allocate an output buffer for deflation in a single pass, and so would be
+   called before deflate().  If that first deflate() call is provided the
+   sourceLen input bytes, an output buffer allocated to the size returned by
+   deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
+   to return Z_STREAM_END.  Note that it is possible for the compressed size to
+   be larger than the value returned by deflateBound() if flush options other
+   than Z_FINISH or Z_NO_FLUSH are used.
 */
 
+ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
+                                       unsigned *pending,
+                                       int *bits));
+/*
+     deflatePending() returns the number of bytes and bits of output that have
+   been generated, but not yet provided in the available output.  The bytes not
+   provided would be due to the available output space having being consumed.
+   The number of bits of output not provided are between 0 and 7, where they
+   await more bits to join them in order to fill out a full byte.  If pending
+   or bits are Z_NULL, then those values are not set.
+
+     deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
+   stream state was inconsistent.
+ */
+
 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
                                      int bits,
                                      int value));
 /*
      deflatePrime() inserts bits in the deflate output stream.  The intent
-  is that this function is used to start off the deflate output with the
-  bits leftover from a previous deflate stream when appending to it.  As such,
-  this function can only be used for raw deflate, and must be used before the
-  first deflate() call after a deflateInit2() or deflateReset().  bits must be
-  less than or equal to 16, and that many of the least significant bits of
-  value will be inserted in the output.
-
-      deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
-   stream state was inconsistent.
+   is that this function is used to start off the deflate output with the bits
+   leftover from a previous deflate stream when appending to it.  As such, this
+   function can only be used for raw deflate, and must be used before the first
+   deflate() call after a deflateInit2() or deflateReset().  bits must be less
+   than or equal to 16, and that many of the least significant bits of value
+   will be inserted in the output.
+
+     deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
+   room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
+   source stream state was inconsistent.
 */
 
 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
                                          gz_headerp head));
 /*
-      deflateSetHeader() provides gzip header information for when a gzip
+     deflateSetHeader() provides gzip header information for when a gzip
    stream is requested by deflateInit2().  deflateSetHeader() may be called
    after deflateInit2() or deflateReset() and before the first call of
    deflate().  The text, time, os, extra field, name, and comment information
@@ -683,11 +820,11 @@ ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
    1.3.x) do not support header crc's, and will report that it is a "multi-part
    gzip file" and give up.
 
-      If deflateSetHeader is not used, the default gzip header has text false,
+     If deflateSetHeader is not used, the default gzip header has text false,
    the time set to zero, and os set to 255, with no extra, name, or comment
    fields.  The gzip header is returned to the default state by deflateReset().
 
-      deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
+     deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
    stream state was inconsistent.
 */
 
@@ -695,43 +832,53 @@ ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
                                      int  windowBits));
 
-     This is another version of inflateInit with an extra parameter. The
+     This is another version of inflateInit with an extra parameter.  The
    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
    before by the caller.
 
      The windowBits parameter is the base two logarithm of the maximum window
    size (the size of the history buffer).  It should be in the range 8..15 for
-   this version of the library. The default value is 15 if inflateInit is used
-   instead. windowBits must be greater than or equal to the windowBits value
+   this version of the library.  The default value is 15 if inflateInit is used
+   instead.  windowBits must be greater than or equal to the windowBits value
    provided to deflateInit2() while compressing, or it must be equal to 15 if
-   deflateInit2() was not used. If a compressed stream with a larger window
+   deflateInit2() was not used.  If a compressed stream with a larger window
    size is given as input, inflate() will return with the error code
    Z_DATA_ERROR instead of trying to allocate a larger window.
 
-     windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
-   determines the window size. inflate() will then process raw deflate data,
+     windowBits can also be zero to request that inflate use the window size in
+   the zlib header of the compressed stream.
+
+     windowBits can also be -8..-15 for raw inflate.  In this case, -windowBits
+   determines the window size.  inflate() will then process raw deflate data,
    not looking for a zlib or gzip header, not generating a check value, and not
-   looking for any check values for comparison at the end of the stream. This
+   looking for any check values for comparison at the end of the stream.  This
    is for use with other formats that use the deflate compressed data format
-   such as zip.  Those formats provide their own check values. If a custom
+   such as zip.  Those formats provide their own check values.  If a custom
    format is developed using the raw deflate format for compressed data, it is
-   recommended that a check value such as an adler32 or a crc32 be applied to
+   recommended that a check value such as an Adler-32 or a CRC-32 be applied to
    the uncompressed data as is done in the zlib, gzip, and zip formats.  For
-   most applications, the zlib format should be used as is. Note that comments
+   most applications, the zlib format should be used as is.  Note that comments
    above on the use in deflateInit2() applies to the magnitude of windowBits.
 
-     windowBits can also be greater than 15 for optional gzip decoding. Add
+     windowBits can also be greater than 15 for optional gzip decoding.  Add
    32 to windowBits to enable zlib and gzip decoding with automatic header
    detection, or add 16 to decode only the gzip format (the zlib format will
-   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is
-   a crc32 instead of an adler32.
+   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
+   CRC-32 instead of an Adler-32.  Unlike the gunzip utility and gzread() (see
+   below), inflate() will not automatically decode concatenated gzip streams.
+   inflate() will return Z_STREAM_END at the end of the gzip stream.  The state
+   would need to be reset to continue decoding a subsequent gzip stream.
 
      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
-   memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
-   is set to null if there is no error message.  inflateInit2 does not perform
-   any decompression apart from reading the zlib header if present: this will
-   be done by inflate(). (So next_in and avail_in may be modified, but next_out
-   and avail_out are unchanged.)
+   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
+   version assumed by the caller, or Z_STREAM_ERROR if the parameters are
+   invalid, such as a null pointer to the structure.  msg is set to null if
+   there is no error message.  inflateInit2 does not perform any decompression
+   apart from possibly reading the zlib header if present: actual decompression
+   will be done by inflate().  (So next_in and avail_in may be modified, but
+   next_out and avail_out are unused and unchanged.) The current implementation
+   of inflateInit2() does not process any header information -- that is
+   deferred until inflate() is called.
 */
 
 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
@@ -739,36 +886,56 @@ ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
                                              uInt  dictLength));
 /*
      Initializes the decompression dictionary from the given uncompressed byte
-   sequence. This function must be called immediately after a call of inflate,
-   if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
-   can be determined from the adler32 value returned by that call of inflate.
+   sequence.  This function must be called immediately after a call of inflate,
+   if that call returned Z_NEED_DICT.  The dictionary chosen by the compressor
+   can be determined from the Adler-32 value returned by that call of inflate.
    The compressor and decompressor must use exactly the same dictionary (see
-   deflateSetDictionary).  For raw inflate, this function can be called
-   immediately after inflateInit2() or inflateReset() and before any call of
-   inflate() to set the dictionary.  The application must insure that the
-   dictionary that was used for compression is provided.
+   deflateSetDictionary).  For raw inflate, this function can be called at any
+   time to set the dictionary.  If the provided dictionary is smaller than the
+   window and there is already data in the window, then the provided dictionary
+   will amend what's there.  The application must insure that the dictionary
+   that was used for compression is provided.
 
      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
-   parameter is invalid (such as NULL dictionary) or the stream state is
+   parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
-   expected one (incorrect adler32 value). inflateSetDictionary does not
+   expected one (incorrect Adler-32 value).  inflateSetDictionary does not
    perform any decompression: this will be done by subsequent calls of
    inflate().
 */
 
-ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
+ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
+                                             Bytef *dictionary,
+                                             uInt  *dictLength));
 /*
-    Skips invalid compressed data until a full flush point (see above the
-  description of deflate with Z_FULL_FLUSH) can be found, or until all
-  available input is skipped. No output is provided.
+     Returns the sliding dictionary being maintained by inflate.  dictLength is
+   set to the number of bytes in the dictionary, and that many bytes are copied
+   to dictionary.  dictionary must have enough space, where 32768 bytes is
+   always enough.  If inflateGetDictionary() is called with dictionary equal to
+   Z_NULL, then only the dictionary length is returned, and nothing is copied.
+   Similary, if dictLength is Z_NULL, then it is not set.
+
+     inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
+   stream state is inconsistent.
+*/
 
-    inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
-  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
-  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
-  case, the application may save the current current value of total_in which
-  indicates where valid compressed data was found. In the error case, the
-  application may repeatedly call inflateSync, providing more input each time,
-  until success or end of the input data.
+ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
+/*
+     Skips invalid compressed data until a possible full flush point (see above
+   for the description of deflate with Z_FULL_FLUSH) can be found, or until all
+   available input is skipped.  No output is provided.
+
+     inflateSync searches for a 00 00 FF FF pattern in the compressed data.
+   All full flush points have this pattern, but not all occurrences of this
+   pattern are full flush points.
+
+     inflateSync returns Z_OK if a possible full flush point has been found,
+   Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
+   has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
+   In the success case, the application may save the current current value of
+   total_in which indicates where valid compressed data was found.  In the
+   error case, the application may repeatedly call inflateSync, providing more
+   input each time, until success or end of the input data.
 */
 
 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
@@ -783,18 +950,32 @@ ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
 
      inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
-   (such as zalloc being NULL). msg is left unchanged in both source and
+   (such as zalloc being Z_NULL).  msg is left unchanged in both source and
    destination.
 */
 
 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
 /*
      This function is equivalent to inflateEnd followed by inflateInit,
-   but does not free and reallocate all the internal decompression state.
-   The stream will keep attributes that may have been set by inflateInit2.
+   but does not free and reallocate the internal decompression state.  The
+   stream will keep attributes that may have been set by inflateInit2.
+
+     inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
+   stream state was inconsistent (such as zalloc or state being Z_NULL).
+*/
 
-      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
-   stream state was inconsistent (such as zalloc or state being NULL).
+ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
+                                      int windowBits));
+/*
+     This function is the same as inflateReset, but it also permits changing
+   the wrap and window size requests.  The windowBits parameter is interpreted
+   the same as it is for inflateInit2.  If the window size is changed, then the
+   memory allocated for the window is freed, and the window will be reallocated
+   by inflate() if needed.
+
+     inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
+   stream state was inconsistent (such as zalloc or state being Z_NULL), or if
+   the windowBits parameter is invalid.
 */
 
 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
@@ -802,54 +983,87 @@ ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
                                      int value));
 /*
      This function inserts bits in the inflate input stream.  The intent is
-  that this function is used to start inflating at a bit position in the
-  middle of a byte.  The provided bits will be used before any bytes are used
-  from next_in.  This function should only be used with raw inflate, and
-  should be used before the first inflate() call after inflateInit2() or
-  inflateReset().  bits must be less than or equal to 16, and that many of the
-  least significant bits of value will be inserted in the input.
-
-      inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
+   that this function is used to start inflating at a bit position in the
+   middle of a byte.  The provided bits will be used before any bytes are used
+   from next_in.  This function should only be used with raw inflate, and
+   should be used before the first inflate() call after inflateInit2() or
+   inflateReset().  bits must be less than or equal to 16, and that many of the
+   least significant bits of value will be inserted in the input.
+
+     If bits is negative, then the input stream bit buffer is emptied.  Then
+   inflatePrime() can be called again to put bits in the buffer.  This is used
+   to clear out bits leftover after feeding inflate a block description prior
+   to feeding inflate codes.
+
+     inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
    stream state was inconsistent.
 */
 
+ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
+/*
+     This function returns two values, one in the lower 16 bits of the return
+   value, and the other in the remaining upper bits, obtained by shifting the
+   return value down 16 bits.  If the upper value is -1 and the lower value is
+   zero, then inflate() is currently decoding information outside of a block.
+   If the upper value is -1 and the lower value is non-zero, then inflate is in
+   the middle of a stored block, with the lower value equaling the number of
+   bytes from the input remaining to copy.  If the upper value is not -1, then
+   it is the number of bits back from the current bit position in the input of
+   the code (literal or length/distance pair) currently being processed.  In
+   that case the lower value is the number of bytes already emitted for that
+   code.
+
+     A code is being processed if inflate is waiting for more input to complete
+   decoding of the code, or if it has completed decoding but is waiting for
+   more output space to write the literal or match data.
+
+     inflateMark() is used to mark locations in the input data for random
+   access, which may be at bit positions, and to note those cases where the
+   output of a code may span boundaries of random access blocks.  The current
+   location in the input stream can be determined from avail_in and data_type
+   as noted in the description for the Z_BLOCK flush parameter for inflate.
+
+     inflateMark returns the value noted above, or -65536 if the provided
+   source stream state was inconsistent.
+*/
+
 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
                                          gz_headerp head));
 /*
-      inflateGetHeader() requests that gzip header information be stored in the
+     inflateGetHeader() requests that gzip header information be stored in the
    provided gz_header structure.  inflateGetHeader() may be called after
    inflateInit2() or inflateReset(), and before the first call of inflate().
    As inflate() processes the gzip stream, head->done is zero until the header
    is completed, at which time head->done is set to one.  If a zlib stream is
    being decoded, then head->done is set to -1 to indicate that there will be
-   no gzip header information forthcoming.  Note that Z_BLOCK can be used to
-   force inflate() to return immediately after header processing is complete
-   and before any actual data is decompressed.
+   no gzip header information forthcoming.  Note that Z_BLOCK or Z_TREES can be
+   used to force inflate() to return immediately after header processing is
+   complete and before any actual data is decompressed.
 
-      The text, time, xflags, and os fields are filled in with the gzip header
+     The text, time, xflags, and os fields are filled in with the gzip header
    contents.  hcrc is set to true if there is a header CRC.  (The header CRC
-   was valid if done is set to one.)  If extra is not Z_NULL, then extra_max
+   was valid if done is set to one.) If extra is not Z_NULL, then extra_max
    contains the maximum number of bytes to write to extra.  Once done is true,
    extra_len contains the actual extra field length, and extra contains the
    extra field, or that field truncated if extra_max is less than extra_len.
    If name is not Z_NULL, then up to name_max characters are written there,
    terminated with a zero unless the length is greater than name_max.  If
    comment is not Z_NULL, then up to comm_max characters are written there,
-   terminated with a zero unless the length is greater than comm_max.  When
-   any of extra, name, or comment are not Z_NULL and the respective field is
-   not present in the header, then that field is set to Z_NULL to signal its
+   terminated with a zero unless the length is greater than comm_max.  When any
+   of extra, name, or comment are not Z_NULL and the respective field is not
+   present in the header, then that field is set to Z_NULL to signal its
    absence.  This allows the use of deflateSetHeader() with the returned
    structure to duplicate the header.  However if those fields are set to
    allocated memory, then the application will need to save those pointers
    elsewhere so that they can be eventually freed.
 
-      If inflateGetHeader is not used, then the header information is simply
+     If inflateGetHeader is not used, then the header information is simply
    discarded.  The header is always checked for validity, including the header
    CRC if present.  inflateReset() will reset the process to discard the header
    information.  The application would need to call inflateGetHeader() again to
    retrieve the header from the next gzip stream.
 
-      inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
+     inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
    stream state was inconsistent.
 */
 
@@ -870,9 +1084,9 @@ ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
      See inflateBack() for the usage of these routines.
 
      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
-   the parameters are invalid, Z_MEM_ERROR if the internal state could not
-   be allocated, or Z_VERSION_ERROR if the version of the library does not
-   match the version of the header file.
+   the parameters are invalid, Z_MEM_ERROR if the internal state could not be
+   allocated, or Z_VERSION_ERROR if the version of the library does not match
+   the version of the header file.
 */
 
 typedef unsigned (*in_func) OF((void FAR *,
@@ -884,25 +1098,26 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
                                     out_func out, void FAR *out_desc));
 /*
      inflateBack() does a raw inflate with a single call using a call-back
-   interface for input and output.  This is more efficient than inflate() for
-   file i/o applications in that it avoids copying between the output and the
-   sliding window by simply making the window itself the output buffer.  This
-   function trusts the application to not change the output buffer passed by
-   the output function, at least until inflateBack() returns.
+   interface for input and output.  This is potentially more efficient than
+   inflate() for file i/o applications, in that it avoids copying between the
+   output and the sliding window by simply making the window itself the output
+   buffer.  inflate() can be faster on modern CPUs when used with large
+   buffers.  inflateBack() trusts the application to not change the output
+   buffer passed by the output function, at least until inflateBack() returns.
 
      inflateBackInit() must be called first to allocate the internal state
    and to initialize the state with the user-provided window buffer.
    inflateBack() may then be used multiple times to inflate a complete, raw
-   deflate stream with each call.  inflateBackEnd() is then called to free
-   the allocated state.
+   deflate stream with each call.  inflateBackEnd() is then called to free the
+   allocated state.
 
      A raw deflate stream is one with no zlib or gzip header or trailer.
    This routine would normally be used in a utility that reads zip or gzip
    files and writes out uncompressed files.  The utility would decode the
-   header and process the trailer on its own, hence this routine expects
-   only the raw deflate stream to decompress.  This is different from the
-   normal behavior of inflate(), which expects either a zlib or gzip header and
-   trailer around the deflate stream.
+   header and process the trailer on its own, hence this routine expects only
+   the raw deflate stream to decompress.  This is different from the default
+   behavior of inflate(), which expects a zlib header and trailer around the
+   deflate stream.
 
      inflateBack() uses two subroutines supplied by the caller that are then
    called by inflateBack() for input and output.  inflateBack() calls those
@@ -911,12 +1126,12 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
    parameters and return types are defined above in the in_func and out_func
    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
    number of bytes of provided input, and a pointer to that input in buf.  If
-   there is no input available, in() must return zero--buf is ignored in that
-   case--and inflateBack() will return a buffer error.  inflateBack() will call
-   out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
-   should return zero on success, or non-zero on failure.  If out() returns
-   non-zero, inflateBack() will return with an error.  Neither in() nor out()
-   are permitted to change the contents of the window provided to
+   there is no input available, in() must return zero -- buf is ignored in that
+   case -- and inflateBack() will return a buffer error.  inflateBack() will
+   call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].
+   out() should return zero on success, or non-zero on failure.  If out()
+   returns non-zero, inflateBack() will return with an error.  Neither in() nor
+   out() are permitted to change the contents of the window provided to
    inflateBackInit(), which is also the buffer that out() uses to write from.
    The length written by out() will be at most the window size.  Any non-zero
    amount of input may be provided by in().
@@ -927,7 +1142,7 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
    must also be initialized, and then if strm->avail_in is not zero, input will
-   initially be taken from strm->next_in[0 .. strm->avail_in - 1].
+   initially be taken from strm->next_in[0 ..  strm->avail_in - 1].
 
      The in_desc and out_desc parameters of inflateBack() is passed as the
    first parameter of in() and out() respectively when they are called.  These
@@ -937,15 +1152,15 @@ ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
      On return, inflateBack() will set strm->next_in and strm->avail_in to
    pass back any unused input that was provided by the last in() call.  The
    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
-   if in() or out() returned an error, Z_DATA_ERROR if there was a format
-   error in the deflate stream (in which case strm->msg is set to indicate the
-   nature of the error), or Z_STREAM_ERROR if the stream was not properly
-   initialized.  In the case of Z_BUF_ERROR, an input or output error can be
-   distinguished using strm->next_in which will be Z_NULL only if in() returned
-   an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
-   out() returning non-zero.  (in() will always be called before out(), so
-   strm->next_in is assured to be defined if out() returns non-zero.)  Note
-   that inflateBack() cannot return Z_OK.
+   if in() or out() returned an error, Z_DATA_ERROR if there was a format error
+   in the deflate stream (in which case strm->msg is set to indicate the nature
+   of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
+   In the case of Z_BUF_ERROR, an input or output error can be distinguished
+   using strm->next_in which will be Z_NULL only if in() returned an error.  If
+   strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
+   non-zero.  (in() will always be called before out(), so strm->next_in is
+   assured to be defined if out() returns non-zero.)  Note that inflateBack()
+   cannot return Z_OK.
 */
 
 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
@@ -966,7 +1181,7 @@ ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
      7.6: size of z_off_t
 
     Compiler, assembler, and debug options:
-     8: DEBUG
+     8: ZLIB_DEBUG
      9: ASMV or ASMINF -- use ASM code
      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
      11: 0 (reserved)
@@ -997,27 +1212,28 @@ ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
      27-31: 0 (reserved)
  */
 
+#ifndef Z_SOLO
 
                         /* utility functions */
 
 /*
-     The following utility functions are implemented on top of the
-   basic stream-oriented functions. To simplify the interface, some
-   default options are assumed (compression level and memory usage,
-   standard memory allocation functions). The source code of these
-   utility functions can easily be modified if you need special options.
+     The following utility functions are implemented on top of the basic
+   stream-oriented functions.  To simplify the interface, some default options
+   are assumed (compression level and memory usage, standard memory allocation
+   functions).  The source code of these utility functions can be modified if
+   you need special options.
 */
 
 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
                                  const Bytef *source, uLong sourceLen));
 /*
      Compresses the source buffer into the destination buffer.  sourceLen is
-   the byte length of the source buffer. Upon entry, destLen is the total
-   size of the destination buffer, which must be at least the value returned
-   by compressBound(sourceLen). Upon exit, destLen is the actual size of the
-   compressed buffer.
-     This function can be used to compress a whole file at once if the
-   input file is mmap'ed.
+   the byte length of the source buffer.  Upon entry, destLen is the total size
+   of the destination buffer, which must be at least the value returned by
+   compressBound(sourceLen).  Upon exit, destLen is the actual size of the
+   compressed data.  compress() is equivalent to compress2() with a level
+   parameter of Z_DEFAULT_COMPRESSION.
+
      compress returns Z_OK if success, Z_MEM_ERROR if there was not
    enough memory, Z_BUF_ERROR if there was not enough room in the output
    buffer.
@@ -1027,12 +1243,12 @@ ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
                                   const Bytef *source, uLong sourceLen,
                                   int level));
 /*
-     Compresses the source buffer into the destination buffer. The level
+     Compresses the source buffer into the destination buffer.  The level
    parameter has the same meaning as in deflateInit.  sourceLen is the byte
-   length of the source buffer. Upon entry, destLen is the total size of the
+   length of the source buffer.  Upon entry, destLen is the total size of the
    destination buffer, which must be at least the value returned by
-   compressBound(sourceLen). Upon exit, destLen is the actual size of the
-   compressed buffer.
+   compressBound(sourceLen).  Upon exit, destLen is the actual size of the
+   compressed data.
 
      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
@@ -1042,159 +1258,306 @@ ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
 /*
      compressBound() returns an upper bound on the compressed size after
-   compress() or compress2() on sourceLen bytes.  It would be used before
-   a compress() or compress2() call to allocate the destination buffer.
+   compress() or compress2() on sourceLen bytes.  It would be used before a
+   compress() or compress2() call to allocate the destination buffer.
 */
 
 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
                                    const Bytef *source, uLong sourceLen));
 /*
      Decompresses the source buffer into the destination buffer.  sourceLen is
-   the byte length of the source buffer. Upon entry, destLen is the total
-   size of the destination buffer, which must be large enough to hold the
-   entire uncompressed data. (The size of the uncompressed data must have
-   been saved previously by the compressor and transmitted to the decompressor
-   by some mechanism outside the scope of this compression library.)
-   Upon exit, destLen is the actual size of the compressed buffer.
-     This function can be used to decompress a whole file at once if the
-   input file is mmap'ed.
+   the byte length of the source buffer.  Upon entry, destLen is the total size
+   of the destination buffer, which must be large enough to hold the entire
+   uncompressed data.  (The size of the uncompressed data must have been saved
+   previously by the compressor and transmitted to the decompressor by some
+   mechanism outside the scope of this compression library.) Upon exit, destLen
+   is the actual size of the uncompressed data.
 
      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
    enough memory, Z_BUF_ERROR if there was not enough room in the output
-   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
+   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.  In
+   the case where there is not enough room, uncompress() will fill the output
+   buffer with the uncompressed data up to that point.
 */
 
+ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest,   uLongf *destLen,
+                                    const Bytef *source, uLong *sourceLen));
+/*
+     Same as uncompress, except that sourceLen is a pointer, where the
+   length of the source is *sourceLen.  On return, *sourceLen is the number of
+   source bytes consumed.
+*/
+
+                        /* gzip file access functions */
+
+/*
+     This library supports reading and writing files in gzip (.gz) format with
+   an interface similar to that of stdio, using the functions that start with
+   "gz".  The gzip format is different from the zlib format.  gzip is a gzip
+   wrapper, documented in RFC 1952, wrapped around a deflate stream.
+*/
 
-typedef voidp gzFile;
+typedef struct gzFile_s *gzFile;    /* semi-opaque gzip file descriptor */
 
-ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));
 /*
-     Opens a gzip (.gz) file for reading or writing. The mode parameter
-   is as in fopen ("rb" or "wb") but can also include a compression level
-   ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
-   Huffman only compression as in "wb1h", or 'R' for run-length encoding
-   as in "wb1R". (See the description of deflateInit2 for more information
-   about the strategy parameter.)
+ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
+
+     Opens a gzip (.gz) file for reading or writing.  The mode parameter is as
+   in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
+   a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
+   compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
+   for fixed code compression as in "wb9F".  (See the description of
+   deflateInit2 for more information about the strategy parameter.)  'T' will
+   request transparent writing or appending with no compression and not using
+   the gzip format.
+
+     "a" can be used instead of "w" to request that the gzip stream that will
+   be written be appended to the file.  "+" will result in an error, since
+   reading and writing to the same gzip file is not supported.  The addition of
+   "x" when writing will create the file exclusively, which fails if the file
+   already exists.  On systems that support it, the addition of "e" when
+   reading or writing will set the flag to close the file on an execve() call.
+
+     These functions, as well as gzip, will read and decode a sequence of gzip
+   streams in a file.  The append function of gzopen() can be used to create
+   such a file.  (Also see gzflush() for another way to do this.)  When
+   appending, gzopen does not test whether the file begins with a gzip stream,
+   nor does it look for the end of the gzip streams to begin appending.  gzopen
+   will simply append a gzip stream to the existing file.
 
      gzopen can be used to read a file which is not in gzip format; in this
-   case gzread will directly read from the file without decompression.
+   case gzread will directly read from the file without decompression.  When
+   reading, this will be detected automatically by looking for the magic two-
+   byte gzip header.
+
+     gzopen returns NULL if the file could not be opened, if there was
+   insufficient memory to allocate the gzFile state, or if an invalid mode was
+   specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
+   errno can be checked to determine if the reason gzopen failed was that the
+   file could not be opened.
+*/
 
-     gzopen returns NULL if the file could not be opened or if there was
-   insufficient memory to allocate the (de)compression state; errno
-   can be checked to distinguish the two cases (if errno is zero, the
-   zlib error is Z_MEM_ERROR).  */
+ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
+/*
+     gzdopen associates a gzFile with the file descriptor fd.  File descriptors
+   are obtained from calls like open, dup, creat, pipe or fileno (if the file
+   has been previously opened with fopen).  The mode parameter is as in gzopen.
+
+     The next call of gzclose on the returned gzFile will also close the file
+   descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
+   fd.  If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
+   mode);.  The duplicated descriptor should be saved to avoid a leak, since
+   gzdopen does not close fd if it fails.  If you are using fileno() to get the
+   file descriptor from a FILE *, then you will have to use dup() to avoid
+   double-close()ing the file descriptor.  Both gzclose() and fclose() will
+   close the associated file descriptor, so they need to have different file
+   descriptors.
+
+     gzdopen returns NULL if there was insufficient memory to allocate the
+   gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
+   provided, or '+' was provided), or if fd is -1.  The file descriptor is not
+   used until the next gz* read, write, seek, or close operation, so gzdopen
+   will not detect if fd is invalid (unless fd is -1).
+*/
 
-ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));
+ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
 /*
-     gzdopen() associates a gzFile with the file descriptor fd.  File
-   descriptors are obtained from calls like open, dup, creat, pipe or
-   fileno (in the file has been previously opened with fopen).
-   The mode parameter is as in gzopen.
-     The next call of gzclose on the returned gzFile will also close the
-   file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
-   descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
-     gzdopen returns NULL if there was insufficient memory to allocate
-   the (de)compression state.
+     Set the internal buffer size used by this library's functions.  The
+   default buffer size is 8192 bytes.  This function must be called after
+   gzopen() or gzdopen(), and before any other calls that read or write the
+   file.  The buffer memory allocation is always deferred to the first read or
+   write.  Three times that size in buffer space is allocated.  A larger buffer
+   size of, for example, 64K or 128K bytes will noticeably increase the speed
+   of decompression (reading).
+
+     The new buffer size also affects the maximum length for gzprintf().
+
+     gzbuffer() returns 0 on success, or -1 on failure, such as being called
+   too late.
 */
 
 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
 /*
-     Dynamically update the compression level or strategy. See the description
-   of deflateInit2 for the meaning of these parameters.
-     gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
-   opened for writing.
+     Dynamically update the compression level or strategy.  See the description
+   of deflateInit2 for the meaning of these parameters.  Previously provided
+   data is flushed before the parameter change.
+
+     gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
+   opened for writing, Z_ERRNO if there is an error writing the flushed data,
+   or Z_MEM_ERROR if there is a memory allocation error.
+*/
+
+ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
+/*
+     Reads the given number of uncompressed bytes from the compressed file.  If
+   the input file is not in gzip format, gzread copies the given number of
+   bytes into the buffer directly from the file.
+
+     After reaching the end of a gzip stream in the input, gzread will continue
+   to read, looking for another gzip stream.  Any number of gzip streams may be
+   concatenated in the input file, and will all be decompressed by gzread().
+   If something other than a gzip stream is encountered after a gzip stream,
+   that remaining trailing garbage is ignored (and no error is returned).
+
+     gzread can be used to read a gzip file that is being concurrently written.
+   Upon reaching the end of the input, gzread will return with the available
+   data.  If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
+   gzclearerr can be used to clear the end of file indicator in order to permit
+   gzread to be tried again.  Z_OK indicates that a gzip stream was completed
+   on the last gzread.  Z_BUF_ERROR indicates that the input file ended in the
+   middle of a gzip stream.  Note that gzread does not return -1 in the event
+   of an incomplete gzip stream.  This error is deferred until gzclose(), which
+   will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
+   stream.  Alternatively, gzerror can be used before gzclose to detect this
+   case.
+
+     gzread returns the number of uncompressed bytes actually read, less than
+   len for end of file, or -1 for error.  If len is too large to fit in an int,
+   then nothing is read, -1 is returned, and the error state is set to
+   Z_STREAM_ERROR.
 */
 
-ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
+ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems,
+                                     gzFile file));
 /*
-     Reads the given number of uncompressed bytes from the compressed file.
-   If the input file was not in gzip format, gzread copies the given number
-   of bytes into the buffer.
-     gzread returns the number of uncompressed bytes actually read (0 for
-   end of file, -1 for error). */
+     Read up to nitems items of size size from file to buf, otherwise operating
+   as gzread() does.  This duplicates the interface of stdio's fread(), with
+   size_t request and return types.  If the library defines size_t, then
+   z_size_t is identical to size_t.  If not, then z_size_t is an unsigned
+   integer type that can contain a pointer.
+
+     gzfread() returns the number of full items read of size size, or zero if
+   the end of the file was reached and a full item could not be read, or if
+   there was an error.  gzerror() must be consulted if zero is returned in
+   order to determine if there was an error.  If the multiplication of size and
+   nitems overflows, i.e. the product does not fit in a z_size_t, then nothing
+   is read, zero is returned, and the error state is set to Z_STREAM_ERROR.
+
+     In the event that the end of file is reached and only a partial item is
+   available at the end, i.e. the remaining uncompressed data length is not a
+   multiple of size, then the final partial item is nevetheless read into buf
+   and the end-of-file flag is set.  The length of the partial item read is not
+   provided, but could be inferred from the result of gztell().  This behavior
+   is the same as the behavior of fread() implementations in common libraries,
+   but it prevents the direct use of gzfread() to read a concurrently written
+   file, reseting and retrying on end-of-file, when size is not 1.
+*/
 
-ZEXTERN int ZEXPORT    gzwrite OF((gzFile file,
-                                   voidpc buf, unsigned len));
+ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
+                                voidpc buf, unsigned len));
 /*
      Writes the given number of uncompressed bytes into the compressed file.
-   gzwrite returns the number of uncompressed bytes actually written
-   (0 in case of error).
+   gzwrite returns the number of uncompressed bytes written or 0 in case of
+   error.
+*/
+
+ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size,
+                                      z_size_t nitems, gzFile file));
+/*
+     gzfwrite() writes nitems items of size size from buf to file, duplicating
+   the interface of stdio's fwrite(), with size_t request and return types.  If
+   the library defines size_t, then z_size_t is identical to size_t.  If not,
+   then z_size_t is an unsigned integer type that can contain a pointer.
+
+     gzfwrite() returns the number of full items written of size size, or zero
+   if there was an error.  If the multiplication of size and nitems overflows,
+   i.e. the product does not fit in a z_size_t, then nothing is written, zero
+   is returned, and the error state is set to Z_STREAM_ERROR.
 */
 
-ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
+ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
 /*
-     Converts, formats, and writes the args to the compressed file under
-   control of the format string, as in fprintf. gzprintf returns the number of
-   uncompressed bytes actually written (0 in case of error).  The number of
-   uncompressed bytes written is limited to 4095. The caller should assure that
-   this limit is not exceeded. If it is exceeded, then gzprintf() will return
-   return an error (0) with nothing written. In this case, there may also be a
+     Converts, formats, and writes the arguments to the compressed file under
+   control of the format string, as in fprintf.  gzprintf returns the number of
+   uncompressed bytes actually written, or a negative zlib error code in case
+   of error.  The number of uncompressed bytes written is limited to 8191, or
+   one less than the buffer size given to gzbuffer().  The caller should assure
+   that this limit is not exceeded.  If it is exceeded, then gzprintf() will
+   return an error (0) with nothing written.  In this case, there may also be a
    buffer overflow with unpredictable consequences, which is possible only if
    zlib was compiled with the insecure functions sprintf() or vsprintf()
    because the secure snprintf() or vsnprintf() functions were not available.
+   This can be determined using zlibCompileFlags().
 */
 
 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
 /*
-      Writes the given null-terminated string to the compressed file, excluding
+     Writes the given null-terminated string to the compressed file, excluding
    the terminating null character.
-      gzputs returns the number of characters written, or -1 in case of error.
+
+     gzputs returns the number of characters written, or -1 in case of error.
 */
 
 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
 /*
-      Reads bytes from the compressed file until len-1 characters are read, or
-   a newline character is read and transferred to buf, or an end-of-file
-   condition is encountered.  The string is then terminated with a null
-   character.
-      gzgets returns buf, or Z_NULL in case of error.
+     Reads bytes from the compressed file until len-1 characters are read, or a
+   newline character is read and transferred to buf, or an end-of-file
+   condition is encountered.  If any characters are read or if len == 1, the
+   string is terminated with a null character.  If no characters are read due
+   to an end-of-file or len < 1, then the buffer is left untouched.
+
+     gzgets returns buf which is a null-terminated string, or it returns NULL
+   for end-of-file or in case of error.  If there was an error, the contents at
+   buf are indeterminate.
 */
 
-ZEXTERN int ZEXPORT    gzputc OF((gzFile file, int c));
+ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
 /*
-      Writes c, converted to an unsigned char, into the compressed file.
-   gzputc returns the value that was written, or -1 in case of error.
+     Writes c, converted to an unsigned char, into the compressed file.  gzputc
+   returns the value that was written, or -1 in case of error.
 */
 
-ZEXTERN int ZEXPORT    gzgetc OF((gzFile file));
+ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
 /*
-      Reads one byte from the compressed file. gzgetc returns this byte
-   or -1 in case of end of file or error.
+     Reads one byte from the compressed file.  gzgetc returns this byte or -1
+   in case of end of file or error.  This is implemented as a macro for speed.
+   As such, it does not do all of the checking the other functions do.  I.e.
+   it does not check to see if file is NULL, nor whether the structure file
+   points to has been clobbered or not.
 */
 
-ZEXTERN int ZEXPORT    gzungetc OF((int c, gzFile file));
+ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
 /*
-      Push one character back onto the stream to be read again later.
-   Only one character of push-back is allowed.  gzungetc() returns the
-   character pushed, or -1 on failure.  gzungetc() will fail if a
-   character has been pushed but not read yet, or if c is -1. The pushed
-   character will be discarded if the stream is repositioned with gzseek()
-   or gzrewind().
+     Push one character back onto the stream to be read as the first character
+   on the next read.  At least one character of push-back is allowed.
+   gzungetc() returns the character pushed, or -1 on failure.  gzungetc() will
+   fail if c is -1, and may fail if a character has been pushed but not read
+   yet.  If gzungetc is used immediately after gzopen or gzdopen, at least the
+   output buffer size of pushed characters is allowed.  (See gzbuffer above.)
+   The pushed character will be discarded if the stream is repositioned with
+   gzseek() or gzrewind().
 */
 
-ZEXTERN int ZEXPORT    gzflush OF((gzFile file, int flush));
+ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
 /*
-     Flushes all pending output into the compressed file. The parameter
-   flush is as in the deflate() function. The return value is the zlib
-   error number (see function gzerror below). gzflush returns Z_OK if
-   the flush parameter is Z_FINISH and all output could be flushed.
-     gzflush should be called only when strictly necessary because it can
-   degrade compression.
+     Flushes all pending output into the compressed file.  The parameter flush
+   is as in the deflate() function.  The return value is the zlib error number
+   (see function gzerror below).  gzflush is only permitted when writing.
+
+     If the flush parameter is Z_FINISH, the remaining data is written and the
+   gzip stream is completed in the output.  If gzwrite() is called again, a new
+   gzip stream will be started in the output.  gzread() is able to read such
+   concatenated gzip streams.
+
+     gzflush should be called only when strictly necessary because it will
+   degrade compression if called too often.
 */
 
-ZEXTERN z_off_t ZEXPORT    gzseek OF((gzFile file,
-                                      z_off_t offset, int whence));
 /*
-      Sets the starting position for the next gzread or gzwrite on the
-   given compressed file. The offset represents a number of bytes in the
-   uncompressed data stream. The whence parameter is defined as in lseek(2);
+ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
+                                   z_off_t offset, int whence));
+
+     Sets the starting position for the next gzread or gzwrite on the given
+   compressed file.  The offset represents a number of bytes in the
+   uncompressed data stream.  The whence parameter is defined as in lseek(2);
    the value SEEK_END is not supported.
+
      If the file is opened for reading, this function is emulated but can be
-   extremely slow. If the file is opened for writing, only forward seeks are
+   extremely slow.  If the file is opened for writing, only forward seeks are
    supported; gzseek then compresses a sequence of zeroes up to the new
    starting position.
 
-      gzseek returns the resulting offset location as measured in bytes from
+     gzseek returns the resulting offset location as measured in bytes from
    the beginning of the uncompressed stream, or -1 in case of error, in
    particular if the file is opened for writing and the new starting position
    would be before the current position.
@@ -1204,68 +1567,134 @@ ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
 /*
      Rewinds the given file. This function is supported only for reading.
 
-   gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
+     gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
 */
 
+/*
 ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
+
+     Returns the starting position for the next gzread or gzwrite on the given
+   compressed file.  This position represents a number of bytes in the
+   uncompressed data stream, and is zero when starting, even if appending or
+   reading a gzip stream from the middle of a file using gzdopen().
+
+     gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
+*/
+
 /*
-     Returns the starting position for the next gzread or gzwrite on the
-   given compressed file. This position represents a number of bytes in the
-   uncompressed data stream.
+ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
 
-   gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
+     Returns the current offset in the file being read or written.  This offset
+   includes the count of bytes that precede the gzip stream, for example when
+   appending or when using gzdopen() for reading.  When reading, the offset
+   does not include as yet unused buffered input.  This information can be used
+   for a progress indicator.  On error, gzoffset() returns -1.
 */
 
 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
 /*
-     Returns 1 when EOF has previously been detected reading the given
-   input stream, otherwise zero.
+     Returns true (1) if the end-of-file indicator has been set while reading,
+   false (0) otherwise.  Note that the end-of-file indicator is set only if the
+   read tried to go past the end of the input, but came up short.  Therefore,
+   just like feof(), gzeof() may return false even if there is no more data to
+   read, in the event that the last read request was for the exact number of
+   bytes remaining in the input file.  This will happen if the input file size
+   is an exact multiple of the buffer size.
+
+     If gzeof() returns true, then the read functions will return no more data,
+   unless the end-of-file indicator is reset by gzclearerr() and the input file
+   has grown since the previous end of file was detected.
 */
 
 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
 /*
-     Returns 1 if file is being read directly without decompression, otherwise
-   zero.
+     Returns true (1) if file is being copied directly while reading, or false
+   (0) if file is a gzip stream being decompressed.
+
+     If the input file is empty, gzdirect() will return true, since the input
+   does not contain a gzip stream.
+
+     If gzdirect() is used immediately after gzopen() or gzdopen() it will
+   cause buffers to be allocated to allow reading the file to determine if it
+   is a gzip file.  Therefore if gzbuffer() is used, it should be called before
+   gzdirect().
+
+     When writing, gzdirect() returns true (1) if transparent writing was
+   requested ("wT" for the gzopen() mode), or false (0) otherwise.  (Note:
+   gzdirect() is not needed when writing.  Transparent writing must be
+   explicitly requested, so the application already knows the answer.  When
+   linking statically, using gzdirect() will include all of the zlib code for
+   gzip file reading and decompression, which may not be desired.)
 */
 
 ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
 /*
-     Flushes all pending output if necessary, closes the compressed file
-   and deallocates all the (de)compression state. The return value is the zlib
-   error number (see function gzerror below).
+     Flushes all pending output if necessary, closes the compressed file and
+   deallocates the (de)compression state.  Note that once file is closed, you
+   cannot call gzerror with file, since its structures have been deallocated.
+   gzclose must not be called more than once on the same file, just as free
+   must not be called more than once on the same allocation.
+
+     gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
+   file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
+   last read ended in the middle of a gzip stream, or Z_OK on success.
+*/
+
+ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
+ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
+/*
+     Same as gzclose(), but gzclose_r() is only for use when reading, and
+   gzclose_w() is only for use when writing or appending.  The advantage to
+   using these instead of gzclose() is that they avoid linking in zlib
+   compression or decompression code that is not used when only reading or only
+   writing respectively.  If gzclose() is used, then both compression and
+   decompression code will be included the application when linking to a static
+   zlib library.
 */
 
 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
 /*
-     Returns the error message for the last error which occurred on the
-   given compressed file. errnum is set to zlib error number. If an
-   error occurred in the file system and not in the compression library,
-   errnum is set to Z_ERRNO and the application may consult errno
-   to get the exact error code.
+     Returns the error message for the last error which occurred on the given
+   compressed file.  errnum is set to zlib error number.  If an error occurred
+   in the file system and not in the compression library, errnum is set to
+   Z_ERRNO and the application may consult errno to get the exact error code.
+
+     The application must not modify the returned string.  Future calls to
+   this function may invalidate the previously returned string.  If file is
+   closed, then the string previously returned by gzerror will no longer be
+   available.
+
+     gzerror() should be used to distinguish errors from end-of-file for those
+   functions above that do not distinguish those cases in their return values.
 */
 
 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
 /*
-     Clears the error and end-of-file flags for file. This is analogous to the
-   clearerr() function in stdio. This is useful for continuing to read a gzip
+     Clears the error and end-of-file flags for file.  This is analogous to the
+   clearerr() function in stdio.  This is useful for continuing to read a gzip
    file that is being written concurrently.
 */
 
+#endif /* !Z_SOLO */
+
                         /* checksum functions */
 
 /*
      These functions are not related to compression but are exported
-   anyway because they might be useful in applications using the
-   compression library.
+   anyway because they might be useful in applications using the compression
+   library.
 */
 
 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
 /*
      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
-   return the updated checksum. If buf is NULL, this function returns
-   the required initial value for the checksum.
-   An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
-   much faster. Usage example:
+   return the updated checksum.  If buf is Z_NULL, this function returns the
+   required initial value for the checksum.
+
+     An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed
+   much faster.
+
+   Usage example:
 
      uLong adler = adler32(0L, Z_NULL, 0);
 
@@ -1275,21 +1704,31 @@ ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
      if (adler != original_adler) error();
 */
 
+ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf,
+                                    z_size_t len));
+/*
+     Same as adler32(), but with a size_t length.
+*/
+
+/*
 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
                                           z_off_t len2));
-/*
+
      Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
    and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
    each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
-   seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
+   seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.  Note
+   that the z_off_t type (like off_t) is a signed integer.  If len2 is
+   negative, the result has no meaning or utility.
 */
 
 ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
 /*
      Update a running CRC-32 with the bytes buf[0..len-1] and return the
-   updated CRC-32. If buf is NULL, this function returns the required initial
-   value for the for the crc. Pre- and post-conditioning (one's complement) is
+   updated CRC-32.  If buf is Z_NULL, this function returns the required
+   initial value for the crc.  Pre- and post-conditioning (one's complement) is
    performed within this function so it shouldn't be done by the application.
+
    Usage example:
 
      uLong crc = crc32(0L, Z_NULL, 0);
@@ -1300,9 +1739,15 @@ ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
      if (crc != original_crc) error();
 */
 
-ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
+ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf,
+                                  z_size_t len));
+/*
+     Same as crc32(), but with a size_t length.
+*/
 
 /*
+ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
+
      Combine two CRC-32 check values into one.  For two sequences of bytes,
    seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
    calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
@@ -1330,27 +1775,135 @@ ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
                                          unsigned char FAR *window,
                                          const char *version,
                                          int stream_size));
-#define deflateInit(strm, level) \
-        deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
-#define inflateInit(strm) \
-        inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
-#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
-        deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
-                      (strategy),           ZLIB_VERSION, sizeof(z_stream))
-#define inflateInit2(strm, windowBits) \
-        inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
-#define inflateBackInit(strm, windowBits, window) \
-        inflateBackInit_((strm), (windowBits), (window), \
-        ZLIB_VERSION, sizeof(z_stream))
-
-
-#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
-    struct internal_state {int dummy;}; /* hack for buggy compilers */
+#ifdef Z_PREFIX_SET
+#  define z_deflateInit(strm, level) \
+          deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
+#  define z_inflateInit(strm) \
+          inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
+#  define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
+          deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
+                        (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
+#  define z_inflateInit2(strm, windowBits) \
+          inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
+                        (int)sizeof(z_stream))
+#  define z_inflateBackInit(strm, windowBits, window) \
+          inflateBackInit_((strm), (windowBits), (window), \
+                           ZLIB_VERSION, (int)sizeof(z_stream))
+#else
+#  define deflateInit(strm, level) \
+          deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
+#  define inflateInit(strm) \
+          inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
+#  define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
+          deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
+                        (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
+#  define inflateInit2(strm, windowBits) \
+          inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
+                        (int)sizeof(z_stream))
+#  define inflateBackInit(strm, windowBits, window) \
+          inflateBackInit_((strm), (windowBits), (window), \
+                           ZLIB_VERSION, (int)sizeof(z_stream))
+#endif
+
+#ifndef Z_SOLO
+
+/* gzgetc() macro and its supporting function and exposed data structure.  Note
+ * that the real internal state is much larger than the exposed structure.
+ * This abbreviated structure exposes just enough for the gzgetc() macro.  The
+ * user should not mess with these exposed elements, since their names or
+ * behavior could change in the future, perhaps even capriciously.  They can
+ * only be used by the gzgetc() macro.  You have been warned.
+ */
+struct gzFile_s {
+    unsigned have;
+    unsigned char *next;
+    z_off64_t pos;
+};
+ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
+#ifdef Z_PREFIX_SET
+#  undef z_gzgetc
+#  define z_gzgetc(g) \
+          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
+#else
+#  define gzgetc(g) \
+          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
+#endif
+
+/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
+ * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
+ * both are true, the application gets the *64 functions, and the regular
+ * functions are changed to 64 bits) -- in case these are set on systems
+ * without large file support, _LFS64_LARGEFILE must also be true
+ */
+#ifdef Z_LARGE64
+   ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
+   ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
+   ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
+   ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
+   ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
+   ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
+#endif
+
+#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
+#  ifdef Z_PREFIX_SET
+#    define z_gzopen z_gzopen64
+#    define z_gzseek z_gzseek64
+#    define z_gztell z_gztell64
+#    define z_gzoffset z_gzoffset64
+#    define z_adler32_combine z_adler32_combine64
+#    define z_crc32_combine z_crc32_combine64
+#  else
+#    define gzopen gzopen64
+#    define gzseek gzseek64
+#    define gztell gztell64
+#    define gzoffset gzoffset64
+#    define adler32_combine adler32_combine64
+#    define crc32_combine crc32_combine64
+#  endif
+#  ifndef Z_LARGE64
+     ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
+     ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
+     ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
+     ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
+     ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
+     ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
+#  endif
+#else
+   ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
+   ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
+   ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
+   ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
+   ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
+   ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
 #endif
 
+#else /* Z_SOLO */
+
+   ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
+   ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
+
+#endif /* !Z_SOLO */
+
+/* undocumented functions */
 ZEXTERN const char   * ZEXPORT zError           OF((int));
-ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp z));
-ZEXTERN const uLongf * ZEXPORT get_crc_table    OF((void));
+ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp));
+ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table    OF((void));
+ZEXTERN int            ZEXPORT inflateUndermine OF((z_streamp, int));
+ZEXTERN int            ZEXPORT inflateValidate OF((z_streamp, int));
+ZEXTERN unsigned long  ZEXPORT inflateCodesUsed OF ((z_streamp));
+ZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
+ZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
+#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
+ZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
+                                            const char *mode));
+#endif
+#if defined(STDC) || defined(Z_HAVE_STDARG_H)
+#  ifndef Z_SOLO
+ZEXTERN int            ZEXPORTVA gzvprintf Z_ARG((gzFile file,
+                                                  const char *format,
+                                                  va_list va));
+#  endif
+#endif
 
 #ifdef __cplusplus
 }
diff --git a/sys/lib/libz/zutil.c b/sys/lib/libz/zutil.c
index ab68c4df9ca..dcd548fbd3e 100644
--- a/sys/lib/libz/zutil.c
+++ b/sys/lib/libz/zutil.c
@@ -1,27 +1,29 @@
-/*	$OpenBSD: zutil.c,v 1.2 2011/07/16 07:25:29 jsing Exp $	*/
+/*	$OpenBSD: zutil.c,v 1.3 2021/07/04 14:24:49 tb Exp $ */
 /* zutil.c -- target dependent utility functions for the compression library
- * Copyright (C) 1995-2005 Jean-loup Gailly.
+ * Copyright (C) 1995-2017 Jean-loup Gailly
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
-
 #include "zutil.h"
 
-#ifndef NO_DUMMY_DECL
-struct internal_state      {int dummy;}; /* for buggy compilers */
+#ifndef _KERNEL
+#ifndef Z_SOLO
+#  include "gzguts.h"
+#endif
 #endif
 
-const char * const z_errmsg[10] = {
-"need dictionary",     /* Z_NEED_DICT       2  */
-"stream end",          /* Z_STREAM_END      1  */
-"",                    /* Z_OK              0  */
-"file error",          /* Z_ERRNO         (-1) */
-"stream error",        /* Z_STREAM_ERROR  (-2) */
-"data error",          /* Z_DATA_ERROR    (-3) */
-"insufficient memory", /* Z_MEM_ERROR     (-4) */
-"buffer error",        /* Z_BUF_ERROR     (-5) */
-"incompatible version",/* Z_VERSION_ERROR (-6) */
-""};
+z_const char * const z_errmsg[10] = {
+    (z_const char *)"need dictionary",     /* Z_NEED_DICT       2  */
+    (z_const char *)"stream end",          /* Z_STREAM_END      1  */
+    (z_const char *)"",                    /* Z_OK              0  */
+    (z_const char *)"file error",          /* Z_ERRNO         (-1) */
+    (z_const char *)"stream error",        /* Z_STREAM_ERROR  (-2) */
+    (z_const char *)"data error",          /* Z_DATA_ERROR    (-3) */
+    (z_const char *)"insufficient memory", /* Z_MEM_ERROR     (-4) */
+    (z_const char *)"buffer error",        /* Z_BUF_ERROR     (-5) */
+    (z_const char *)"incompatible version",/* Z_VERSION_ERROR (-6) */
+    (z_const char *)""
+};
 
 
 const char * ZEXPORT zlibVersion()
@@ -34,31 +36,31 @@ uLong ZEXPORT zlibCompileFlags()
     uLong flags;
 
     flags = 0;
-    switch (sizeof(uInt)) {
+    switch ((int)(sizeof(uInt))) {
     case 2:     break;
     case 4:     flags += 1;     break;
     case 8:     flags += 2;     break;
     default:    flags += 3;
     }
-    switch (sizeof(uLong)) {
+    switch ((int)(sizeof(uLong))) {
     case 2:     break;
     case 4:     flags += 1 << 2;        break;
     case 8:     flags += 2 << 2;        break;
     default:    flags += 3 << 2;
     }
-    switch (sizeof(voidpf)) {
+    switch ((int)(sizeof(voidpf))) {
     case 2:     break;
     case 4:     flags += 1 << 4;        break;
     case 8:     flags += 2 << 4;        break;
     default:    flags += 3 << 4;
     }
-    switch (sizeof(z_off_t)) {
+    switch ((int)(sizeof(z_off_t))) {
     case 2:     break;
     case 4:     flags += 1 << 6;        break;
     case 8:     flags += 2 << 6;        break;
     default:    flags += 3 << 6;
     }
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
     flags += 1 << 8;
 #endif
 #if defined(ASMV) || defined(ASMINF)
@@ -85,41 +87,41 @@ uLong ZEXPORT zlibCompileFlags()
 #ifdef FASTEST
     flags += 1L << 21;
 #endif
-#ifdef STDC
+#if defined(STDC) || defined(Z_HAVE_STDARG_H)
 #  ifdef NO_vsnprintf
-        flags += 1L << 25;
+    flags += 1L << 25;
 #    ifdef HAS_vsprintf_void
-        flags += 1L << 26;
+    flags += 1L << 26;
 #    endif
 #  else
 #    ifdef HAS_vsnprintf_void
-        flags += 1L << 26;
+    flags += 1L << 26;
 #    endif
 #  endif
 #else
-        flags += 1L << 24;
+    flags += 1L << 24;
 #  ifdef NO_snprintf
-        flags += 1L << 25;
+    flags += 1L << 25;
 #    ifdef HAS_sprintf_void
-        flags += 1L << 26;
+    flags += 1L << 26;
 #    endif
 #  else
 #    ifdef HAS_snprintf_void
-        flags += 1L << 26;
+    flags += 1L << 26;
 #    endif
 #  endif
 #endif
     return flags;
 }
 
-#ifdef DEBUG_LIBZ
-
+#ifdef ZLIB_DEBUG
+#include <stdlib.h>
 #  ifndef verbose
 #    define verbose 0
 #  endif
-int z_verbose = verbose;
+int ZLIB_INTERNAL z_verbose = verbose;
 
-void z_error (m)
+void ZLIB_INTERNAL z_error (m)
     char *m;
 {
     fprintf(stderr, "%s\n", m);
@@ -146,7 +148,7 @@ const char * ZEXPORT zError(err)
 
 #ifndef HAVE_MEMCPY
 
-void zmemcpy(dest, source, len)
+void ZLIB_INTERNAL zmemcpy(dest, source, len)
     Bytef* dest;
     const Bytef* source;
     uInt  len;
@@ -157,7 +159,7 @@ void zmemcpy(dest, source, len)
     } while (--len != 0);
 }
 
-int zmemcmp(s1, s2, len)
+int ZLIB_INTERNAL zmemcmp(s1, s2, len)
     const Bytef* s1;
     const Bytef* s2;
     uInt  len;
@@ -170,7 +172,7 @@ int zmemcmp(s1, s2, len)
     return 0;
 }
 
-void zmemzero(dest, len)
+void ZLIB_INTERNAL zmemzero(dest, len)
     Bytef* dest;
     uInt  len;
 {
@@ -181,6 +183,7 @@ void zmemzero(dest, len)
 }
 #endif
 
+#ifndef Z_SOLO
 
 #ifdef SYS16BIT
 
@@ -213,11 +216,13 @@ local ptr_table table[MAX_PTR];
  * a protected system like OS/2. Use Microsoft C instead.
  */
 
-voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
+voidpf ZLIB_INTERNAL zcalloc (voidpf opaque, unsigned items, unsigned size)
 {
-    voidpf buf = opaque; /* just to make some compilers happy */
+    voidpf buf;
     ulg bsize = (ulg)items*size;
 
+    (void)opaque;
+
     /* If we allocate less than 65520 bytes, we assume that farmalloc
      * will return a usable pointer which doesn't have to be normalized.
      */
@@ -237,9 +242,12 @@ voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
     return buf;
 }
 
-void  zcfree (voidpf opaque, voidpf ptr)
+void ZLIB_INTERNAL zcfree (voidpf opaque, voidpf ptr)
 {
     int n;
+
+    (void)opaque;
+
     if (*(ush*)&ptr != 0) { /* object < 64K */
         farfree(ptr);
         return;
@@ -255,7 +263,6 @@ void  zcfree (voidpf opaque, voidpf ptr)
         next_ptr--;
         return;
     }
-    ptr = opaque; /* just to make some compilers happy */
     Assert(0, "zcfree: ptr not found");
 }
 
@@ -272,15 +279,15 @@ void  zcfree (voidpf opaque, voidpf ptr)
 #  define _hfree   hfree
 #endif
 
-voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
+voidpf ZLIB_INTERNAL zcalloc (voidpf opaque, uInt items, uInt size)
 {
-    if (opaque) opaque = 0; /* to make compiler happy */
+    (void)opaque;
     return _halloc((long)items, size);
 }
 
-void  zcfree (voidpf opaque, voidpf ptr)
+void ZLIB_INTERNAL zcfree (voidpf opaque, voidpf ptr)
 {
-    if (opaque) opaque = 0; /* to make compiler happy */
+    (void)opaque;
     _hfree(ptr);
 }
 
@@ -297,24 +304,25 @@ extern voidp  calloc OF((uInt items, uInt size));
 extern void   free   OF((voidpf ptr));
 #endif
 
-voidpf zcalloc (opaque, items, size)
+voidpf ZLIB_INTERNAL zcalloc (opaque, items, size)
     voidpf opaque;
     unsigned items;
     unsigned size;
 {
-    if (opaque) items += size - size; /* make compiler happy */
-    if (items * size == 0)
-	return (NULL);
-    return sizeof(uInt) > 2 ? (voidpf)malloc(items * size) :
-                              (voidpf)calloc(items, size);
+    (void)opaque;
+    if (items == 0 || size == 0)
+        return (NULL);
+    return reallocarray(NULL, items, size);
 }
 
-void  zcfree (opaque, ptr)
+void ZLIB_INTERNAL zcfree (opaque, ptr)
     voidpf opaque;
     voidpf ptr;
 {
+    (void)opaque;
     free(ptr);
-    if (opaque) return; /* make compiler happy */
 }
 
 #endif /* MY_ZCALLOC */
+
+#endif /* !Z_SOLO */
diff --git a/sys/lib/libz/zutil.h b/sys/lib/libz/zutil.h
index 28eb10d8ab6..8b10a3fbb0a 100644
--- a/sys/lib/libz/zutil.h
+++ b/sys/lib/libz/zutil.h
@@ -1,6 +1,5 @@
-/*	$OpenBSD: zutil.h,v 1.18 2011/07/07 02:57:24 deraadt Exp $	*/
 /* zutil.h -- internal interface and configuration of the compression library
- * Copyright (C) 1995-2005 Jean-loup Gailly.
+ * Copyright (C) 1995-2016 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -9,52 +8,50 @@
    subject to change. Applications should only use zlib.h.
  */
 
-
 #ifndef ZUTIL_H
 #define ZUTIL_H
 
-#define ZLIB_INTERNAL
+#ifdef HAVE_HIDDEN
+#  define ZLIB_INTERNAL __attribute__((visibility ("hidden")))
+#else
+#  define ZLIB_INTERNAL
+#endif
+
 #include "zlib.h"
 
 #ifdef _KERNEL
 #include <sys/param.h>
 #include <sys/systm.h>
+
+#define BUILDFIXED
 #define MY_ZCALLOC
-#else
+#define NOBYFOUR
 
+typedef long ptrdiff_t;
+#else
 #ifdef _STANDALONE
 #include <lib/libsa/stand.h>
 #else
-#ifdef STDC
-#  ifndef _WIN32_WCE
+#if defined(STDC) && !defined(Z_SOLO)
+#  if !(defined(_WIN32_WCE) && defined(_MSC_VER))
 #    include <stddef.h>
 #  endif
 #  include <string.h>
 #  include <stdlib.h>
 #endif
-#ifdef NO_ERRNO_H
-#   ifdef _WIN32_WCE
-      /* The Microsoft C Run-Time Library for Windows CE doesn't have
-       * errno.  We define it as a global variable to simplify porting.
-       * Its value is always 0 and should not be used.  We rename it to
-       * avoid conflict with other libraries that use the same workaround.
-       */
-#     define errno z_errno
-#   endif
-    extern int errno;
-#else
-#  ifndef _WIN32_WCE
-#    include <errno.h>
-#  endif
 #endif
 #endif
 
+#ifdef Z_SOLO
+   typedef long ptrdiff_t;  /* guess -- will be caught if guess is wrong */
 #endif
 
 #ifndef local
 #  define local static
 #endif
-/* compile with -Dlocal if your debugger can't find static symbols */
+/* since "static" is used to mean two completely different things in C, we
+   define "local" for the non-static meaning of "static", for readability
+   (compile with -Dlocal if your debugger can't find static symbols) */
 
 typedef unsigned char  uch;
 typedef uch FAR uchf;
@@ -62,13 +59,13 @@ typedef unsigned short ush;
 typedef ush FAR ushf;
 typedef unsigned long  ulg;
 
-extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
+extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 /* (size given to avoid silly warnings with Visual C++) */
 
 #define ERR_MSG(err) z_errmsg[Z_NEED_DICT-(err)]
 
 #define ERR_RETURN(strm,err) \
-  return (strm->msg = (char*)ERR_MSG(err), (err))
+  return (strm->msg = ERR_MSG(err), (err))
 /* To be used only when the state is known to be valid */
 
         /* common constants */
@@ -100,70 +97,90 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 
 #if defined(MSDOS) || (defined(WINDOWS) && !defined(WIN32))
 #  define OS_CODE  0x00
-#  if defined(__TURBOC__) || defined(__BORLANDC__)
-#    if(__STDC__ == 1) && (defined(__LARGE__) || defined(__COMPACT__))
-       /* Allow compilation with ANSI keywords only enabled */
-       void _Cdecl farfree( void *block );
-       void *_Cdecl farmalloc( unsigned long nbytes );
-#    else
-#      include <alloc.h>
+#  ifndef Z_SOLO
+#    if defined(__TURBOC__) || defined(__BORLANDC__)
+#      if (__STDC__ == 1) && (defined(__LARGE__) || defined(__COMPACT__))
+         /* Allow compilation with ANSI keywords only enabled */
+         void _Cdecl farfree( void *block );
+         void *_Cdecl farmalloc( unsigned long nbytes );
+#      else
+#        include <alloc.h>
+#      endif
+#    else /* MSC or DJGPP */
+#      include <malloc.h>
 #    endif
-#  else /* MSC or DJGPP */
-#    include <malloc.h>
 #  endif
 #endif
 
 #ifdef AMIGA
-#  define OS_CODE  0x01
+#  define OS_CODE  1
 #endif
 
 #if defined(VAXC) || defined(VMS)
-#  define OS_CODE  0x02
+#  define OS_CODE  2
 #  define F_OPEN(name, mode) \
      fopen((name), (mode), "mbc=60", "ctx=stm", "rfm=fix", "mrs=512")
 #endif
 
+#ifdef __370__
+#  if __TARGET_LIB__ < 0x20000000
+#    define OS_CODE 4
+#  elif __TARGET_LIB__ < 0x40000000
+#    define OS_CODE 11
+#  else
+#    define OS_CODE 8
+#  endif
+#endif
+
 #if defined(ATARI) || defined(atarist)
-#  define OS_CODE  0x05
+#  define OS_CODE  5
 #endif
 
 #ifdef OS2
-#  define OS_CODE  0x06
-#  ifdef M_I86
-     #include <malloc.h>
+#  define OS_CODE  6
+#  if defined(M_I86) && !defined(Z_SOLO)
+#    include <malloc.h>
 #  endif
 #endif
 
 #if defined(MACOS) || defined(TARGET_OS_MAC)
-#  define OS_CODE  0x07
-#  if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
-#    include <unix.h> /* for fdopen */
-#  else
-#    ifndef fdopen
-#      define fdopen(fd,mode) NULL /* No fdopen() */
+#  define OS_CODE  7
+#  ifndef Z_SOLO
+#    if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
+#      include <unix.h> /* for fdopen */
+#    else
+#      ifndef fdopen
+#        define fdopen(fd,mode) NULL /* No fdopen() */
+#      endif
 #    endif
 #  endif
 #endif
 
-#ifdef TOPS20
-#  define OS_CODE  0x0a
+#ifdef __acorn
+#  define OS_CODE 13
 #endif
 
-#ifdef WIN32
-#  ifndef __CYGWIN__  /* Cygwin is Unix, not Win32 */
-#    define OS_CODE  0x0b
-#  endif
+#if defined(WIN32) && !defined(__CYGWIN__)
+#  define OS_CODE  10
+#endif
+
+#ifdef _BEOS_
+#  define OS_CODE  16
 #endif
 
-#ifdef __50SERIES /* Prime/PRIMOS */
-#  define OS_CODE  0x0f
+#ifdef __TOS_OS400__
+#  define OS_CODE 18
+#endif
+
+#ifdef __APPLE__
+#  define OS_CODE 19
 #endif
 
 #if defined(_BEOS_) || defined(RISCOS)
 #  define fdopen(fd,mode) NULL /* No fdopen() */
 #endif
 
-#if (defined(_MSC_VER) && (_MSC_VER > 600))
+#if (defined(_MSC_VER) && (_MSC_VER > 600)) && !defined __INTERIX
 #  if defined(_WIN32_WCE)
 #    define fdopen(fd,mode) NULL /* No fdopen() */
 #    ifndef _PTRDIFF_T_DEFINED
@@ -175,10 +192,23 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #  endif
 #endif
 
+#if defined(__BORLANDC__) && !defined(MSDOS)
+  #pragma warn -8004
+  #pragma warn -8008
+  #pragma warn -8066
+#endif
+
+/* provide prototypes for these when building zlib without LFS */
+#if !defined(_WIN32) && \
+    (!defined(_LARGEFILE64_SOURCE) || _LFS64_LARGEFILE-0 == 0)
+    ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
+    ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
+#endif
+
         /* common defaults */
 
 #ifndef OS_CODE
-#  define OS_CODE  0x03  /* assume Unix */
+#  define OS_CODE  3     /* assume Unix */
 #endif
 
 #ifndef F_OPEN
@@ -187,40 +217,7 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 
          /* functions */
 
-#if defined(STDC99) || (defined(__TURBOC__) && __TURBOC__ >= 0x550)
-#  ifndef HAVE_VSNPRINTF
-#    define HAVE_VSNPRINTF
-#  endif
-#endif
-#if defined(__CYGWIN__)
-#  ifndef HAVE_VSNPRINTF
-#    define HAVE_VSNPRINTF
-#  endif
-#endif
-#ifndef HAVE_VSNPRINTF
-#  ifdef MSDOS
-     /* vsnprintf may exist on some MS-DOS compilers (DJGPP?),
-        but for now we just assume it doesn't. */
-#    define NO_vsnprintf
-#  endif
-#  ifdef __TURBOC__
-#    define NO_vsnprintf
-#  endif
-#  ifdef WIN32
-     /* In Win32, vsnprintf is available as the "non-ANSI" _vsnprintf. */
-#    if !defined(vsnprintf) && !defined(NO_vsnprintf)
-#      define vsnprintf _vsnprintf
-#    endif
-#  endif
-#  ifdef __SASC
-#    define NO_vsnprintf
-#  endif
-#endif
-#ifdef VMS
-#  define NO_vsnprintf
-#endif
-
-#if defined(pyr)
+#if defined(pyr) || defined(Z_SOLO)
 #  define NO_MEMCPY
 #endif
 #if defined(SMALL_MEDIUM) && !defined(_MSC_VER) && !defined(__SC__)
@@ -244,16 +241,16 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #    define zmemzero(dest, len) memset(dest, 0, len)
 #  endif
 #else
-   extern void zmemcpy  OF((Bytef* dest, const Bytef* source, uInt len));
-   extern int  zmemcmp  OF((const Bytef* s1, const Bytef* s2, uInt len));
-   extern void zmemzero OF((Bytef* dest, uInt len));
+   void ZLIB_INTERNAL zmemcpy OF((Bytef* dest, const Bytef* source, uInt len));
+   int ZLIB_INTERNAL zmemcmp OF((const Bytef* s1, const Bytef* s2, uInt len));
+   void ZLIB_INTERNAL zmemzero OF((Bytef* dest, uInt len));
 #endif
 
 /* Diagnostic functions */
-#ifdef DEBUG_LIBZ
+#ifdef ZLIB_DEBUG
 #  include <stdio.h>
-   extern int z_verbose;
-   extern void z_error    OF((char *m));
+   extern int ZLIB_INTERNAL z_verbose;
+   extern void ZLIB_INTERNAL z_error OF((char *m));
 #  define Assert(cond,msg) {if(!(cond)) z_error(msg);}
 #  define Trace(x) {if (z_verbose>=0) fprintf x ;}
 #  define Tracev(x) {if (z_verbose>0) fprintf x ;}
@@ -269,13 +266,19 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #  define Tracecv(c,x)
 #endif
 
-
-voidpf zcalloc OF((voidpf opaque, unsigned items, unsigned size));
-void   zcfree  OF((voidpf opaque, voidpf ptr));
+#ifndef Z_SOLO
+   voidpf ZLIB_INTERNAL zcalloc OF((voidpf opaque, unsigned items,
+                                    unsigned size));
+   void ZLIB_INTERNAL zcfree  OF((voidpf opaque, voidpf ptr));
+#endif
 
 #define ZALLOC(strm, items, size) \
            (*((strm)->zalloc))((strm)->opaque, (items), (size))
 #define ZFREE(strm, addr)  (*((strm)->zfree))((strm)->opaque, (voidpf)(addr))
 #define TRY_FREE(s, p) {if (p) ZFREE(s, p);}
 
+/* Reverse the bytes in a 32-bit value */
+#define ZSWAP32(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
+                    (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
+
 #endif /* ZUTIL_H */