/* unlzw.c -- decompress files in LZW format. * The code in this file is directly derived from the public domain 'compress' * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies, * Ken Turkowski, Dave Mack and Peter Jannesen. * * This is a temporary version which will be rewritten in some future version * to accommodate in-memory decompression. */ #ifdef RCSID static char rcsid[] = "$Id: unlzw.c,v 1.1 1995/10/18 08:40:54 deraadt Exp $"; #endif #include #include "tailor.h" #ifdef HAVE_UNISTD_H # include #endif #ifndef NO_FCNTL_H # include #endif #include "gzip.h" #include "lzw.h" typedef unsigned char char_type; typedef long code_int; typedef unsigned long count_int; typedef unsigned short count_short; typedef unsigned long cmp_code_int; #define MAXCODE(n) (1L << (n)) #ifndef REGISTERS # define REGISTERS 2 #endif #define REG1 #define REG2 #define REG3 #define REG4 #define REG5 #define REG6 #define REG7 #define REG8 #define REG9 #define REG10 #define REG11 #define REG12 #define REG13 #define REG14 #define REG15 #define REG16 #if REGISTERS >= 1 # undef REG1 # define REG1 register #endif #if REGISTERS >= 2 # undef REG2 # define REG2 register #endif #if REGISTERS >= 3 # undef REG3 # define REG3 register #endif #if REGISTERS >= 4 # undef REG4 # define REG4 register #endif #if REGISTERS >= 5 # undef REG5 # define REG5 register #endif #if REGISTERS >= 6 # undef REG6 # define REG6 register #endif #if REGISTERS >= 7 # undef REG7 # define REG7 register #endif #if REGISTERS >= 8 # undef REG8 # define REG8 register #endif #if REGISTERS >= 9 # undef REG9 # define REG9 register #endif #if REGISTERS >= 10 # undef REG10 # define REG10 register #endif #if REGISTERS >= 11 # undef REG11 # define REG11 register #endif #if REGISTERS >= 12 # undef REG12 # define REG12 register #endif #if REGISTERS >= 13 # undef REG13 # define REG13 register #endif #if REGISTERS >= 14 # undef REG14 # define REG14 register #endif #if REGISTERS >= 15 # undef REG15 # define REG15 register #endif #if REGISTERS >= 16 # undef REG16 # define REG16 register #endif #ifndef BYTEORDER # define BYTEORDER 0000 #endif #ifndef NOALLIGN # define NOALLIGN 0 #endif union bytes { long word; struct { #if BYTEORDER == 4321 char_type b1; char_type b2; char_type b3; char_type b4; #else #if BYTEORDER == 1234 char_type b4; char_type b3; char_type b2; char_type b1; #else # undef BYTEORDER int dummy; #endif #endif } bytes; }; #if BYTEORDER == 4321 && NOALLIGN == 1 # define input(b,o,c,n,m){ \ (c) = (*(long *)(&(b)[(o)>>3])>>((o)&0x7))&(m); \ (o) += (n); \ } #else # define input(b,o,c,n,m){ \ REG1 char_type *p = &(b)[(o)>>3]; \ (c) = ((((long)(p[0]))|((long)(p[1])<<8)| \ ((long)(p[2])<<16))>>((o)&0x7))&(m); \ (o) += (n); \ } #endif #ifndef MAXSEG_64K /* DECLARE(ush, tab_prefix, (1<>1] # define clear_tab_prefixof() \ memzero(tab_prefix0, 128), \ memzero(tab_prefix1, 128); #endif #define de_stack ((char_type *)(&d_buf[DIST_BUFSIZE-1])) #define tab_suffixof(i) tab_suffix[i] int block_mode = BLOCK_MODE; /* block compress mode -C compatible with 2.0 */ /* ============================================================================ * Decompress in to out. This routine adapts to the codes in the * file building the "string" table on-the-fly; requiring no table to * be stored in the compressed file. * IN assertions: the buffer inbuf contains already the beginning of * the compressed data, from offsets iptr to insize-1 included. * The magic header has already been checked and skipped. * bytes_in and bytes_out have been initialized. */ int unlzw(in, out) int in, out; /* input and output file descriptors */ { REG2 char_type *stackp; REG3 code_int code; REG4 int finchar; REG5 code_int oldcode; REG6 code_int incode; REG7 long inbits; REG8 long posbits; REG9 int outpos; /* REG10 int insize; (global) */ REG11 unsigned bitmask; REG12 code_int free_ent; REG13 code_int maxcode; REG14 code_int maxmaxcode; REG15 int n_bits; REG16 int rsize; #ifdef MAXSEG_64K tab_prefix[0] = tab_prefix0; tab_prefix[1] = tab_prefix1; #endif maxbits = get_byte(); block_mode = maxbits & BLOCK_MODE; if ((maxbits & LZW_RESERVED) != 0) { WARN((stderr, "\n%s: %s: warning, unknown flags 0x%x\n", progname, ifname, maxbits & LZW_RESERVED)); } maxbits &= BIT_MASK; maxmaxcode = MAXCODE(maxbits); if (maxbits > BITS) { fprintf(stderr, "\n%s: %s: compressed with %d bits, can only handle %d bits\n", progname, ifname, maxbits, BITS); exit_code = ERROR; return ERROR; } rsize = insize; maxcode = MAXCODE(n_bits = INIT_BITS)-1; bitmask = (1<= 0 ; --code) { tab_suffixof(code) = (char_type)code; } do { REG1 int i; int e; int o; resetbuf: e = insize-(o = (posbits>>3)); for (i = 0 ; i < e ; ++i) { inbuf[i] = inbuf[i+o]; } insize = e; posbits = 0; if (insize < INBUF_EXTRA) { if ((rsize = read(in, (char*)inbuf+insize, INBUFSIZ)) == EOF) { read_error(); } insize += rsize; bytes_in += (ulg)rsize; } inbits = ((rsize != 0) ? ((long)insize - insize%n_bits)<<3 : ((long)insize<<3)-(n_bits-1)); while (inbits > posbits) { if (free_ent > maxcode) { posbits = ((posbits-1) + ((n_bits<<3)-(posbits-1+(n_bits<<3))%(n_bits<<3))); ++n_bits; if (n_bits == maxbits) { maxcode = maxmaxcode; } else { maxcode = MAXCODE(n_bits)-1; } bitmask = (1<= 256) error("corrupt input."); outbuf[outpos++] = (char_type)(finchar = (int)(oldcode=code)); continue; } if (code == CLEAR && block_mode) { clear_tab_prefixof(); free_ent = FIRST - 1; posbits = ((posbits-1) + ((n_bits<<3)-(posbits-1+(n_bits<<3))%(n_bits<<3))); maxcode = MAXCODE(n_bits = INIT_BITS)-1; bitmask = (1<= free_ent) { /* Special case for KwKwK string. */ if (code > free_ent) { #ifdef DEBUG char_type *p; posbits -= n_bits; p = &inbuf[posbits>>3]; fprintf(stderr, "code:%ld free_ent:%ld n_bits:%d insize:%u\n", code, free_ent, n_bits, insize); fprintf(stderr, "posbits:%ld inbuf:%02X %02X %02X %02X %02X\n", posbits, p[-1],p[0],p[1],p[2],p[3]); #endif if (!test && outpos > 0) { write_buf(out, (char*)outbuf, outpos); bytes_out += (ulg)outpos; } error(to_stdout ? "corrupt input." : "corrupt input. Use zcat to recover some data."); } *--stackp = (char_type)finchar; code = oldcode; } while ((cmp_code_int)code >= (cmp_code_int)256) { /* Generate output characters in reverse order */ *--stackp = tab_suffixof(code); code = tab_prefixof(code); } *--stackp = (char_type)(finchar = tab_suffixof(code)); /* And put them out in forward order */ { REG1 int i; if (outpos+(i = (de_stack-stackp)) >= OUTBUFSIZ) { do { if (i > OUTBUFSIZ-outpos) i = OUTBUFSIZ-outpos; if (i > 0) { memcpy(outbuf+outpos, stackp, i); outpos += i; } if (outpos >= OUTBUFSIZ) { if (!test) { write_buf(out, (char*)outbuf, outpos); bytes_out += (ulg)outpos; } outpos = 0; } stackp+= i; } while ((i = (de_stack-stackp)) > 0); } else { memcpy(outbuf+outpos, stackp, i); outpos += i; } } if ((code = free_ent) < maxmaxcode) { /* Generate the new entry. */ tab_prefixof(code) = (unsigned short)oldcode; tab_suffixof(code) = (char_type)finchar; free_ent = code+1; } oldcode = incode; /* Remember previous code. */ } } while (rsize != 0); if (!test && outpos > 0) { write_buf(out, (char*)outbuf, outpos); bytes_out += (ulg)outpos; } return OK; }