1 /* vi: set sw=4 ts=4: */
3 * gunzip implementation for busybox
5 * Based on GNU gzip v1.2.4 Copyright (C) 1992-1993 Jean-loup Gailly.
7 * Originally adjusted for busybox by Sven Rudolph <sr1@inf.tu-dresden.de>
8 * based on gzip sources
10 * Adjusted further by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
11 * to support files as well as stdin/stdout, and to generally behave itself wrt
12 * command line handling.
14 * General cleanup to better adhere to the style guide and make use of standard
15 * busybox functions by Glenn McGrath <bug1@optushome.com.au>
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25 * General Public License for more details.
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, write to the Free Software
29 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
32 * gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
33 * Copyright (C) 1992-1993 Jean-loup Gailly
34 * The unzip code was written and put in the public domain by Mark Adler.
35 * Portions of the lzw code are derived from the public domain 'compress'
36 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
37 * Ken Turkowski, Dave Mack and Peter Jannesen.
39 * See the license_msg below and the file COPYING for the software license.
40 * See the file algorithm.doc for the compression algorithms and file formats.
44 static char *license_msg[] = {
45 " Copyright (C) 1992-1993 Jean-loup Gailly",
46 " This program is free software; you can redistribute it and/or modify",
47 " it under the terms of the GNU General Public License as published by",
48 " the Free Software Foundation; either version 2, or (at your option)",
49 " any later version.",
51 " This program is distributed in the hope that it will be useful,",
52 " but WITHOUT ANY WARRANTY; without even the implied warranty of",
53 " MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the",
54 " GNU General Public License for more details.",
56 " You should have received a copy of the GNU General Public License",
57 " along with this program; if not, write to the Free Software",
58 " Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.",
63 #include <sys/types.h>
68 #define BB_DECLARE_EXTERN
69 #define bb_need_memory_exhausted
70 #define bb_need_name_too_long
71 #include "../messages.c"
73 FILE *in_file, *out_file;
75 /* these are freed by gz_close */
76 static unsigned char *window;
77 static unsigned long *crc_table;
79 static unsigned long crc = 0xffffffffL; /* shift register contents */
81 /* Return codes from gzip */
82 static const int ERROR = 1;
85 * window size--must be a power of two, and
86 * at least 32K for zip's deflate method
88 static const int WSIZE = 0x8000;
90 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
91 static const int BMAX = 16; /* maximum bit length of any code (16 for explode) */
92 static const int N_MAX = 288; /* maximum number of codes in any set */
94 static long bytes_out; /* number of output bytes */
95 static unsigned long outcnt; /* bytes in output buffer */
97 unsigned hufts; /* track memory usage */
98 unsigned long bb; /* bit buffer */
99 unsigned bk; /* bits in bit buffer */
101 typedef struct huft_s {
102 unsigned char e; /* number of extra bits or operation */
103 unsigned char b; /* number of bits in this code or subcode */
105 unsigned short n; /* literal, length base, or distance base */
106 struct huft_s *t; /* pointer to next level of table */
110 unsigned short mask_bits[] = {
112 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
113 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
116 //static int error_number = 0;
117 /* ========================================================================
118 * Signal and error handler.
121 static void abort_gzip()
123 error_msg("gzip aborted\n");
127 static void make_crc_table()
129 unsigned long table_entry; /* crc shift register */
130 unsigned long poly = 0; /* polynomial exclusive-or pattern */
131 int i; /* counter for all possible eight bit values */
132 int k; /* byte being shifted into crc apparatus */
134 /* terms of polynomial defining this crc (except x^32): */
135 static int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
137 crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long));
139 /* Make exclusive-or pattern from polynomial (0xedb88320) */
140 for (i = 0; i < sizeof(p)/sizeof(int); i++)
141 poly |= 1L << (31 - p[i]);
143 /* Compute and print table of CRC's, five per line */
144 for (i = 0; i < 256; i++) {
146 /* The idea to initialize the register with the byte instead of
147 * zero was stolen from Haruhiko Okumura's ar002
149 for (k = 8; k; k--) {
150 table_entry = table_entry & 1 ? (table_entry >> 1) ^ poly : table_entry >> 1;
152 crc_table[i]=table_entry;
156 /* ===========================================================================
157 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
158 * (Used for the decompressed data only.)
167 for (n = 0; n < outcnt; n++) {
168 crc = crc_table[((int) crc ^ (window[n])) & 0xff] ^ (crc >> 8);
171 if (fwrite(window, 1, outcnt, out_file) != outcnt) {
172 error_msg_and_die("Couldnt write");
174 bytes_out += (unsigned long) outcnt;
179 * Free the malloc'ed tables built by huft_build(), which makes a linked
180 * list of the tables it made, with the links in a dummy first entry of
184 static int huft_free(huft_t *t)
188 /* Go through linked list, freeing from the malloced (t[-1]) address. */
190 while (p != (huft_t *) NULL) {
198 /* Given a list of code lengths and a maximum table size, make a set of
199 * tables to decode that set of codes. Return zero on success, one if
200 * the given code set is incomplete (the tables are still built in this
201 * case), two if the input is invalid (all zero length codes or an
202 * oversubscribed set of lengths), and three if not enough memory.
204 * b: code lengths in bits (all assumed <= BMAX)
205 * n: number of codes (assumed <= N_MAX)
206 * s: number of simple-valued codes (0..s-1)
207 * d: list of base values for non-simple codes
208 * e: list of extra bits for non-simple codes
209 * t: result: starting table
210 * m: maximum lookup bits, returns actual
212 static int huft_build(unsigned int *b, const unsigned int n, const unsigned int s,
213 const unsigned short *d, const unsigned short *e, huft_t **t, int *m)
215 unsigned a; /* counter for codes of length k */
216 unsigned c[BMAX + 1]; /* bit length count table */
217 unsigned f; /* i repeats in table every f entries */
218 int g; /* maximum code length */
219 int h; /* table level */
220 register unsigned i; /* counter, current code */
221 register unsigned j; /* counter */
222 register int k; /* number of bits in current code */
223 int l; /* bits per table (returned in m) */
224 register unsigned *p; /* pointer into c[], b[], or v[] */
225 register huft_t *q; /* points to current table */
226 huft_t r; /* table entry for structure assignment */
227 huft_t *u[BMAX]; /* table stack */
228 unsigned v[N_MAX]; /* values in order of bit length */
229 register int w; /* bits before this table == (l * h) */
230 unsigned x[BMAX + 1]; /* bit offsets, then code stack */
231 unsigned *xp; /* pointer into x */
232 int y; /* number of dummy codes added */
233 unsigned z; /* number of entries in current table */
235 /* Generate counts for each bit length */
236 memset ((void *)(c), 0, sizeof(c));
240 c[*p]++; /* assume all entries <= BMAX */
241 p++; /* Can't combine with above line (Solaris bug) */
243 if (c[0] == n) { /* null input--all zero length codes */
244 *t = (huft_t *) NULL;
249 /* Find minimum and maximum length, bound *m by those */
251 for (j = 1; j <= BMAX; j++)
254 k = j; /* minimum code length */
255 if ((unsigned) l < j)
257 for (i = BMAX; i; i--)
260 g = i; /* maximum code length */
261 if ((unsigned) l > i)
265 /* Adjust last length count to fill out codes, if needed */
266 for (y = 1 << j; j < i; j++, y <<= 1)
268 return 2; /* bad input: more codes than bits */
273 /* Generate starting offsets into the value table for each length */
277 while (--i) { /* note that i == g from above */
281 /* Make a table of values in order of bit lengths */
289 /* Generate the Huffman codes and for each, make the table entries */
290 x[0] = i = 0; /* first Huffman code is zero */
291 p = v; /* grab values in bit order */
292 h = -1; /* no tables yet--level -1 */
293 w = -l; /* bits decoded == (l * h) */
294 u[0] = (huft_t *) NULL; /* just to keep compilers happy */
295 q = (huft_t *) NULL; /* ditto */
298 /* go through the bit lengths (k already is bits in shortest code) */
299 for (; k <= g; k++) {
302 /* here i is the Huffman code of length k bits for value *p */
303 /* make tables up to required level */
306 w += l; /* previous table always l bits */
308 /* compute minimum size table less than or equal to l bits */
309 z = (z = g - w) > (unsigned) l ? l : z; /* upper limit on table size */
310 if ((f = 1 << (j = k - w)) > a + 1) { /* try a k-w bit table *//* too few codes for k-w bit table */
311 f -= a + 1; /* deduct codes from patterns left */
313 while (++j < z) { /* try smaller tables up to z bits */
314 if ((f <<= 1) <= *++xp)
315 break; /* enough codes to use up j bits */
316 f -= *xp; /* else deduct codes from patterns */
319 z = 1 << j; /* table entries for j-bit table */
321 /* allocate and link in new table */
322 if ((q = (huft_t *) xmalloc((z + 1) * sizeof(huft_t))) == NULL) {
326 return 3; /* not enough memory */
328 hufts += z + 1; /* track memory usage */
329 *t = q + 1; /* link to list for huft_free() */
330 *(t = &(q->v.t)) = NULL;
331 u[h] = ++q; /* table starts after link */
333 /* connect to last table, if there is one */
335 x[h] = i; /* save pattern for backing up */
336 r.b = (unsigned char) l; /* bits to dump before this table */
337 r.e = (unsigned char) (16 + j); /* bits in this table */
338 r.v.t = q; /* pointer to this table */
339 j = i >> (w - l); /* (get around Turbo C bug) */
340 u[h - 1][j] = r; /* connect to last table */
344 /* set up table entry in r */
345 r.b = (unsigned char) (k - w);
347 r.e = 99; /* out of values--invalid code */
349 r.e = (unsigned char) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */
350 r.v.n = (unsigned short) (*p); /* simple code is just the value */
351 p++; /* one compiler does not like *p++ */
353 r.e = (unsigned char) e[*p - s]; /* non-simple--look up in lists */
357 /* fill code-like entries with r */
359 for (j = i >> w; j < z; j += f)
362 /* backwards increment the k-bit code i */
363 for (j = 1 << (k - 1); i & j; j >>= 1)
367 /* backup over finished tables */
368 while ((i & ((1 << w) - 1)) != x[h]) {
369 h--; /* don't need to update q */
374 /* Return true (1) if we were given an incomplete table */
375 return y != 0 && g != 1;
379 * inflate (decompress) the codes in a deflated (compressed) block.
380 * Return an error code or zero if it all goes ok.
382 * tl, td: literal/length and distance decoder tables
383 * bl, bd: number of bits decoded by tl[] and td[]
385 static int inflate_codes(huft_t *tl, huft_t *td, int bl, int bd)
387 register unsigned long e; /* table entry flag/number of extra bits */
388 unsigned long n, d; /* length and index for copy */
389 unsigned long w; /* current window position */
390 huft_t *t; /* pointer to table entry */
391 unsigned ml, md; /* masks for bl and bd bits */
392 register unsigned long b; /* bit buffer */
393 register unsigned k; /* number of bits in bit buffer */
395 /* make local copies of globals */
396 b = bb; /* initialize bit buffer */
398 w = outcnt; /* initialize window position */
400 /* inflate the coded data */
401 ml = mask_bits[bl]; /* precompute masks for speed */
403 for (;;) { /* do until end of block */
404 while (k < (unsigned) bl) {
405 b |= ((unsigned long)fgetc(in_file)) << k;
408 if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
417 b |= ((unsigned long)fgetc(in_file)) << k;
420 } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
423 if (e == 16) { /* then it's a literal */
424 window[w++] = (unsigned char) t->v.n;
430 } else { /* it's an EOB or a length */
432 /* exit if end of block */
437 /* get length of block to copy */
439 b |= ((unsigned long)fgetc(in_file)) << k;
442 n = t->v.n + ((unsigned) b & mask_bits[e]);
446 /* decode distance of block to copy */
447 while (k < (unsigned) bd) {
448 b |= ((unsigned long)fgetc(in_file)) << k;
452 if ((e = (t = td + ((unsigned) b & md))->e) > 16)
460 b |= ((unsigned long)fgetc(in_file)) << k;
463 } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
467 b |= ((unsigned long)fgetc(in_file)) << k;
470 d = w - t->v.n - ((unsigned) b & mask_bits[e]);
476 n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n : e);
477 #if !defined(NOMEMCPY) && !defined(DEBUG)
478 if (w - d >= e) { /* (this test assumes unsigned comparison) */
479 memcpy(window + w, window + d, e);
482 } else /* do it slow to avoid memcpy() overlap */
483 #endif /* !NOMEMCPY */
485 window[w++] = window[d++];
496 /* restore the globals from the locals */
497 outcnt = w; /* restore global window pointer */
498 bb = b; /* restore global bit buffer */
506 * decompress an inflated block
509 * GLOBAL VARIABLES: bb, kk,
511 static int inflate_block(int *e)
513 unsigned t; /* block type */
514 register unsigned long b; /* bit buffer */
515 register unsigned k; /* number of bits in bit buffer */
516 static unsigned short cplens[] = { /* Copy lengths for literal codes 257..285 */
517 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
518 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
520 /* note: see note #13 above about the 258 in this list. */
521 static unsigned short cplext[] = { /* Extra bits for literal codes 257..285 */
522 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
523 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
525 static unsigned short cpdist[] = { /* Copy offsets for distance codes 0..29 */
526 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
527 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
528 8193, 12289, 16385, 24577
530 static unsigned short cpdext[] = { /* Extra bits for distance codes */
531 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
532 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
536 /* make local bit buffer */
540 /* read in last block bit */
542 b |= ((unsigned long)fgetc(in_file)) << k;
549 /* read in block type */
551 b |= ((unsigned long)fgetc(in_file)) << k;
554 t = (unsigned) b & 3;
558 /* restore the global bit buffer */
562 /* inflate that block type */
564 case 0: /* Inflate stored */
566 unsigned long n; /* number of bytes in block */
567 unsigned long w; /* current window position */
568 register unsigned long b_stored; /* bit buffer */
569 register unsigned long k_stored; /* number of bits in bit buffer */
571 /* make local copies of globals */
572 b_stored = bb; /* initialize bit buffer */
574 w = outcnt; /* initialize window position */
576 /* go to byte boundary */
581 /* get the length and its complement */
582 while (k_stored < 16) {
583 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
586 n = ((unsigned) b_stored & 0xffff);
589 while (k_stored < 16) {
590 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
593 if (n != (unsigned) ((~b_stored) & 0xffff)) {
594 return 1; /* error in compressed data */
599 /* read and output the compressed data */
601 while (k_stored < 8) {
602 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
605 window[w++] = (unsigned char) b_stored;
606 if (w == (unsigned long)WSIZE) {
615 /* restore the globals from the locals */
616 outcnt = w; /* restore global window pointer */
617 bb = b_stored; /* restore global bit buffer */
621 case 1: /* Inflate fixed
622 * decompress an inflated type 1 (fixed Huffman codes) block. We should
623 * either replace this with a custom decoder, or at least precompute the
627 int i; /* temporary variable */
628 huft_t *tl; /* literal/length code table */
629 huft_t *td; /* distance code table */
630 int bl; /* lookup bits for tl */
631 int bd; /* lookup bits for td */
632 unsigned int l[288]; /* length list for huft_build */
634 /* set up literal table */
635 for (i = 0; i < 144; i++) {
638 for (; i < 256; i++) {
641 for (; i < 280; i++) {
644 for (; i < 288; i++) { /* make a complete, but wrong code set */
648 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
652 /* set up distance table */
653 for (i = 0; i < 30; i++) { /* make an incomplete code set */
657 if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
662 /* decompress until an end-of-block code */
663 if (inflate_codes(tl, td, bl, bd))
666 /* free the decoding tables, return */
671 case 2: /* Inflate dynamic */
673 /* Tables for deflate from PKZIP's appnote.txt. */
674 static unsigned border[] = { /* Order of the bit length code lengths */
675 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
677 int dbits = 6; /* bits in base distance lookup table */
678 int lbits = 9; /* bits in base literal/length lookup table */
680 int i; /* temporary variables */
682 unsigned l; /* last length */
683 unsigned m; /* mask for bit lengths table */
684 unsigned n; /* number of lengths to get */
685 huft_t *tl; /* literal/length code table */
686 huft_t *td; /* distance code table */
687 int bl; /* lookup bits for tl */
688 int bd; /* lookup bits for td */
689 unsigned nb; /* number of bit length codes */
690 unsigned nl; /* number of literal/length codes */
691 unsigned nd; /* number of distance codes */
693 unsigned ll[286 + 30]; /* literal/length and distance code lengths */
694 register unsigned long b_dynamic; /* bit buffer */
695 register unsigned k_dynamic; /* number of bits in bit buffer */
697 /* make local bit buffer */
701 /* read in table lengths */
702 while (k_dynamic < 5) {
703 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
706 nl = 257 + ((unsigned) b_dynamic & 0x1f); /* number of literal/length codes */
709 while (k_dynamic < 5) {
710 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
713 nd = 1 + ((unsigned) b_dynamic & 0x1f); /* number of distance codes */
716 while (k_dynamic < 4) {
717 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
720 nb = 4 + ((unsigned) b_dynamic & 0xf); /* number of bit length codes */
723 if (nl > 286 || nd > 30) {
724 return 1; /* bad lengths */
727 /* read in bit-length-code lengths */
728 for (j = 0; j < nb; j++) {
729 while (k_dynamic < 3) {
730 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
733 ll[border[j]] = (unsigned) b_dynamic & 7;
737 for (; j < 19; j++) {
741 /* build decoding table for trees--single level, 7 bit lookup */
743 if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
747 return i; /* incomplete code set */
750 /* read in literal and distance code lengths */
754 while ((unsigned) i < n) {
755 while (k_dynamic < (unsigned) bl) {
756 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
759 j = (td = tl + ((unsigned) b_dynamic & m))->b;
763 if (j < 16) { /* length of code in bits (0..15) */
764 ll[i++] = l = j; /* save last length in l */
766 else if (j == 16) { /* repeat last length 3 to 6 times */
767 while (k_dynamic < 2) {
768 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
771 j = 3 + ((unsigned) b_dynamic & 3);
774 if ((unsigned) i + j > n) {
780 } else if (j == 17) { /* 3 to 10 zero length codes */
781 while (k_dynamic < 3) {
782 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
785 j = 3 + ((unsigned) b_dynamic & 7);
788 if ((unsigned) i + j > n) {
795 } else { /* j == 18: 11 to 138 zero length codes */
796 while (k_dynamic < 7) {
797 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
800 j = 11 + ((unsigned) b_dynamic & 0x7f);
803 if ((unsigned) i + j > n) {
813 /* free decoding table for trees */
816 /* restore the global bit buffer */
820 /* build the decoding tables for literal/length and distance codes */
822 if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
824 error_msg("Incomplete literal tree");
827 return i; /* incomplete code set */
830 if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
832 error_msg("incomplete distance tree");
836 return i; /* incomplete code set */
839 /* decompress until an end-of-block code */
840 if (inflate_codes(tl, td, bl, bd))
843 /* free the decoding tables, return */
855 * decompress an inflated entry
857 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
861 int e; /* last block flag */
862 int r; /* result code */
863 unsigned h = 0; /* maximum struct huft's malloc'ed */
865 /* initialize window, bit buffer */
870 /* decompress until the last block */
873 if ((r = inflate_block(&e)) != 0) {
881 /* flush out window */
888 /* ===========================================================================
889 * Unzip in to out. This routine works on both gzip and pkzip files.
891 * IN assertions: the buffer inbuf contains already the beginning of
892 * the compressed data, from offsets inptr to insize-1 included.
893 * The magic header has already been checked. The output buffer is cleared.
894 * in, out: input and output file descriptors
896 extern int unzip(FILE *l_in_file, FILE *l_out_file)
898 const int extra_field = 0x04; /* bit 2 set: extra field present */
899 const int orig_name = 0x08; /* bit 3 set: original file name present */
900 const int comment = 0x10; /* bit 4 set: file comment present */
901 unsigned char buf[8]; /* extended local header */
902 unsigned char flags; /* compression flags */
903 char magic[2]; /* magic header */
905 typedef void (*sig_type) (int);
906 int exit_code=0; /* program exit code */
910 out_file = l_out_file;
912 if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
913 (void) signal(SIGINT, (sig_type) abort_gzip);
916 // if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
917 // (void) signal(SIGTERM, (sig_type) abort_gzip);
921 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
922 (void) signal(SIGHUP, (sig_type) abort_gzip);
926 /* Allocate all global buffers (for DYN_ALLOC option) */
927 window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
931 /* set the buffer size */
932 setvbuf(in_file, NULL, _IOFBF, 0x8000);
934 magic[0] = fgetc(in_file);
935 magic[1] = fgetc(in_file);
937 /* Magic header for gzip files, 1F 8B = \037\213 */
938 if (memcmp(magic, "\037\213", 2) != 0) {
939 error_msg("Invalid gzip magic");
943 method = (int) fgetc(in_file);
945 error_msg("unknown method %d -- get newer version of gzip", method);
950 flags = (unsigned char) fgetc(in_file);
952 /* Ignore time stamp(4), extra flags(1), OS type(1) */
953 for (i = 0; i < 6; i++)
956 if ((flags & extra_field) != 0) {
958 extra = fgetc(in_file);
959 extra += fgetc(in_file) << 8;
961 for (i = 0; i < extra; i++)
965 /* Discard original name if any */
966 if ((flags & orig_name) != 0) {
967 while (fgetc(in_file) != 0); /* null */
970 /* Discard file comment if any */
971 if ((flags & comment) != 0) {
972 while (fgetc(in_file) != 0); /* null */
976 printf("it failed\n");
977 return(exit_code); /* error message already emitted */
988 error_msg(memory_exhausted);
989 } else if (res != 0) {
990 error_msg("invalid compressed data--format violated");
994 error_msg("internal error, invalid method");
997 /* Get the crc and original length
998 * crc32 (see algorithm.doc)
999 * uncompressed input size modulo 2^32
1001 fread(buf, 1, 8, in_file);
1003 /* Validate decompression - crc */
1004 if (((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
1005 error_msg("invalid compressed data--crc error");
1007 /* Validate decompression - size */
1008 if (((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
1009 error_msg("invalid compressed data--length error");
1019 * This needs access to global variables wondow and crc_table, so its not in its own file.
1021 extern void gz_close(int gunzip_pid)
1023 if (kill(gunzip_pid, SIGTERM) == -1) {
1024 error_msg_and_die("*** Couldnt kill old gunzip process *** aborting");
1027 if (waitpid(gunzip_pid, NULL, 0) == -1) {
1028 printf("Couldnt wait ?");