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authorJason Downs <downsj@cvs.openbsd.org>1997-02-06 02:56:57 +0000
committerJason Downs <downsj@cvs.openbsd.org>1997-02-06 02:56:57 +0000
commit40ab3310e733696c3abaa3ad2934c9975275dfca (patch)
treebd5b3f9a272ad6516701b4a983eccf9e9e3fe1fa /sys/lib/libz/adler32.c
parent9e2c2dbcee4a3ad77a401ec09f3cc6ae4c030520 (diff)
Add libz and make libsa aware of it. From NetBSD.
Diffstat (limited to 'sys/lib/libz/adler32.c')
-rw-r--r--sys/lib/libz/adler32.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/sys/lib/libz/adler32.c b/sys/lib/libz/adler32.c
new file mode 100644
index 00000000000..3a16a40534d
--- /dev/null
+++ b/sys/lib/libz/adler32.c
@@ -0,0 +1,48 @@
+/* adler32.c -- compute the Adler-32 checksum of a data stream
+ * Copyright (C) 1995-1996 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+/* $Id: adler32.c,v 1.1 1997/02/06 02:56:49 downsj Exp $ */
+
+#include "zlib.h"
+
+#define BASE 65521L /* 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 */
+
+#define DO1(buf,i) {s1 += buf[i]; s2 += s1;}
+#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
+#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
+#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
+#define DO16(buf) DO8(buf,0); DO8(buf,8);
+
+/* ========================================================================= */
+uLong adler32(adler, buf, len)
+ uLong adler;
+ const Bytef *buf;
+ uInt len;
+{
+ unsigned long s1 = adler & 0xffff;
+ unsigned long s2 = (adler >> 16) & 0xffff;
+ int k;
+
+ if (buf == Z_NULL) return 1L;
+
+ while (len > 0) {
+ k = len < NMAX ? len : NMAX;
+ len -= k;
+ while (k >= 16) {
+ DO16(buf);
+ buf += 16;
+ k -= 16;
+ }
+ if (k != 0) do {
+ s1 += *buf++;
+ s2 += s1;
+ } while (--k);
+ s1 %= BASE;
+ s2 %= BASE;
+ }
+ return (s2 << 16) | s1;
+}