--- /dev/null
+/* 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[] = "$Id$";
+#endif
+
+#include <sys/types.h>
+
+#include "tailor.h"
+
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+#ifndef NO_FCNTL_H
+# include <fcntl.h>
+#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<<BITS)); -- prefix code */
+# define tab_prefixof(i) tab_prefix[i]
+# define clear_tab_prefixof() memzero(tab_prefix, 256);
+#else
+ /* DECLARE(ush, tab_prefix0, (1<<(BITS-1)); -- prefix for even codes */
+ /* DECLARE(ush, tab_prefix1, (1<<(BITS-1)); -- prefix for odd codes */
+ ush *tab_prefix[2];
+# define tab_prefixof(i) tab_prefix[(i)&1][(i)>>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<<n_bits)-1;
+ oldcode = -1;
+ finchar = 0;
+ outpos = 0;
+ posbits = inptr<<3;
+
+ free_ent = ((block_mode) ? FIRST : 256);
+
+ clear_tab_prefixof(); /* Initialize the first 256 entries in the table. */
+
+ for (code = 255 ; code >= 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<<n_bits)-1;
+ goto resetbuf;
+ }
+ input(inbuf,posbits,code,n_bits,bitmask);
+ Tracev((stderr, "%d ", code));
+
+ if (oldcode == -1) {
+ if (code >= 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<<n_bits)-1;
+ goto resetbuf;
+ }
+ incode = code;
+ stackp = de_stack;
+
+ if (code >= 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;
+}
projects / debian / gzip / commitdiff