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 <andersee@debian.org> to support
11 * 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>
70 static FILE *in_file, *out_file;
72 /* these are freed by gz_close */
73 static unsigned char *window;
74 static unsigned long *crc_table;
76 static unsigned long crc; /* shift register contents */
78 /* Return codes from gzip */
79 static const int ERROR = 1;
82 * window size--must be a power of two, and
83 * at least 32K for zip's deflate method
85 static const int WSIZE = 0x8000;
87 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
88 static const int BMAX = 16; /* maximum bit length of any code (16 for explode) */
89 static const int N_MAX = 288; /* maximum number of codes in any set */
91 static long bytes_out; /* number of output bytes */
92 static unsigned long outcnt; /* bytes in output buffer */
94 static unsigned hufts; /* track memory usage */
95 static unsigned long bb; /* bit buffer */
96 static unsigned bk; /* bits in bit buffer */
98 typedef struct huft_s {
99 unsigned char e; /* number of extra bits or operation */
100 unsigned char b; /* number of bits in this code or subcode */
102 unsigned short n; /* literal, length base, or distance base */
103 struct huft_s *t; /* pointer to next level of table */
107 static const unsigned short mask_bits[] = {
109 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
110 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
113 //static int error_number = 0;
114 /* ========================================================================
115 * Signal and error handler.
118 static void abort_gzip(void)
120 error_msg("gzip aborted\n");
124 static void make_crc_table(void)
126 const unsigned long poly = 0xedb88320; /* polynomial exclusive-or pattern */
127 unsigned short i; /* counter for all possible eight bit values */
129 /* initial shift register value */
131 crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long));
133 /* Compute and print table of CRC's, five per line */
134 for (i = 0; i < 256; i++) {
135 unsigned long table_entry; /* crc shift register */
136 char k; /* byte being shifted into crc apparatus */
139 /* The idea to initialize the register with the byte instead of
140 * zero was stolen from Haruhiko Okumura's ar002
142 for (k = 8; k; k--) {
143 table_entry = table_entry & 1 ? (table_entry >> 1) ^ poly : table_entry >> 1;
145 crc_table[i]=table_entry;
149 /* ===========================================================================
150 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
151 * (Used for the decompressed data only.)
153 static void flush_window(void)
160 for (n = 0; n < outcnt; n++) {
161 crc = crc_table[((int) crc ^ (window[n])) & 0xff] ^ (crc >> 8);
164 if (fwrite(window, 1, outcnt, out_file) != outcnt) {
165 error_msg_and_die("Couldnt write");
167 bytes_out += (unsigned long) outcnt;
172 * Free the malloc'ed tables built by huft_build(), which makes a linked
173 * list of the tables it made, with the links in a dummy first entry of
177 static int huft_free(huft_t *t)
181 /* Go through linked list, freeing from the malloced (t[-1]) address. */
183 while (p != (huft_t *) NULL) {
191 typedef unsigned char extra_bits_t;
193 /* Given a list of code lengths and a maximum table size, make a set of
194 * tables to decode that set of codes. Return zero on success, one if
195 * the given code set is incomplete (the tables are still built in this
196 * case), two if the input is invalid (all zero length codes or an
197 * oversubscribed set of lengths), and three if not enough memory.
199 * b: code lengths in bits (all assumed <= BMAX)
200 * n: number of codes (assumed <= N_MAX)
201 * s: number of simple-valued codes (0..s-1)
202 * d: list of base values for non-simple codes
203 * e: list of extra bits for non-simple codes
204 * t: result: starting table
205 * m: maximum lookup bits, returns actual
207 static int huft_build(unsigned int *b, const unsigned int n, const unsigned int s,
208 const unsigned short *d, const extra_bits_t *e, huft_t **t, int *m)
210 unsigned a; /* counter for codes of length k */
211 unsigned c[BMAX + 1]; /* bit length count table */
212 unsigned f; /* i repeats in table every f entries */
213 int g; /* maximum code length */
214 int h; /* table level */
215 register unsigned i; /* counter, current code */
216 register unsigned j; /* counter */
217 register int k; /* number of bits in current code */
218 int l; /* bits per table (returned in m) */
219 register unsigned *p; /* pointer into c[], b[], or v[] */
220 register huft_t *q; /* points to current table */
221 huft_t r; /* table entry for structure assignment */
222 huft_t *u[BMAX]; /* table stack */
223 unsigned v[N_MAX]; /* values in order of bit length */
224 register int w; /* bits before this table == (l * h) */
225 unsigned x[BMAX + 1]; /* bit offsets, then code stack */
226 unsigned *xp; /* pointer into x */
227 int y; /* number of dummy codes added */
228 unsigned z; /* number of entries in current table */
230 /* Generate counts for each bit length */
231 memset ((void *)(c), 0, sizeof(c));
235 c[*p]++; /* assume all entries <= BMAX */
236 p++; /* Can't combine with above line (Solaris bug) */
238 if (c[0] == n) { /* null input--all zero length codes */
239 *t = (huft_t *) NULL;
244 /* Find minimum and maximum length, bound *m by those */
246 for (j = 1; j <= BMAX; j++)
249 k = j; /* minimum code length */
250 if ((unsigned) l < j)
252 for (i = BMAX; i; i--)
255 g = i; /* maximum code length */
256 if ((unsigned) l > i)
260 /* Adjust last length count to fill out codes, if needed */
261 for (y = 1 << j; j < i; j++, y <<= 1)
263 return 2; /* bad input: more codes than bits */
268 /* Generate starting offsets into the value table for each length */
272 while (--i) { /* note that i == g from above */
276 /* Make a table of values in order of bit lengths */
284 /* Generate the Huffman codes and for each, make the table entries */
285 x[0] = i = 0; /* first Huffman code is zero */
286 p = v; /* grab values in bit order */
287 h = -1; /* no tables yet--level -1 */
288 w = -l; /* bits decoded == (l * h) */
289 u[0] = (huft_t *) NULL; /* just to keep compilers happy */
290 q = (huft_t *) NULL; /* ditto */
293 /* go through the bit lengths (k already is bits in shortest code) */
294 for (; k <= g; k++) {
297 /* here i is the Huffman code of length k bits for value *p */
298 /* make tables up to required level */
301 w += l; /* previous table always l bits */
303 /* compute minimum size table less than or equal to l bits */
304 z = (z = g - w) > (unsigned) l ? l : z; /* upper limit on table size */
305 if ((f = 1 << (j = k - w)) > a + 1) { /* try a k-w bit table *//* too few codes for k-w bit table */
306 f -= a + 1; /* deduct codes from patterns left */
308 while (++j < z) { /* try smaller tables up to z bits */
309 if ((f <<= 1) <= *++xp)
310 break; /* enough codes to use up j bits */
311 f -= *xp; /* else deduct codes from patterns */
314 z = 1 << j; /* table entries for j-bit table */
316 /* allocate and link in new table */
317 q = (huft_t *) xmalloc((z + 1) * sizeof(huft_t));
319 hufts += z + 1; /* track memory usage */
320 *t = q + 1; /* link to list for huft_free() */
321 *(t = &(q->v.t)) = NULL;
322 u[h] = ++q; /* table starts after link */
324 /* connect to last table, if there is one */
326 x[h] = i; /* save pattern for backing up */
327 r.b = (unsigned char) l; /* bits to dump before this table */
328 r.e = (unsigned char) (16 + j); /* bits in this table */
329 r.v.t = q; /* pointer to this table */
330 j = i >> (w - l); /* (get around Turbo C bug) */
331 u[h - 1][j] = r; /* connect to last table */
335 /* set up table entry in r */
336 r.b = (unsigned char) (k - w);
338 r.e = 99; /* out of values--invalid code */
340 r.e = (unsigned char) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */
341 r.v.n = (unsigned short) (*p); /* simple code is just the value */
342 p++; /* one compiler does not like *p++ */
344 r.e = (unsigned char) e[*p - s]; /* non-simple--look up in lists */
348 /* fill code-like entries with r */
350 for (j = i >> w; j < z; j += f)
353 /* backwards increment the k-bit code i */
354 for (j = 1 << (k - 1); i & j; j >>= 1)
358 /* backup over finished tables */
359 while ((i & ((1 << w) - 1)) != x[h]) {
360 h--; /* don't need to update q */
365 /* Return true (1) if we were given an incomplete table */
366 return y != 0 && g != 1;
370 * inflate (decompress) the codes in a deflated (compressed) block.
371 * Return an error code or zero if it all goes ok.
373 * tl, td: literal/length and distance decoder tables
374 * bl, bd: number of bits decoded by tl[] and td[]
376 static int inflate_codes(huft_t *tl, huft_t *td, int bl, int bd)
378 register unsigned long e; /* table entry flag/number of extra bits */
379 unsigned long n, d; /* length and index for copy */
380 unsigned long w; /* current window position */
381 huft_t *t; /* pointer to table entry */
382 unsigned ml, md; /* masks for bl and bd bits */
383 register unsigned long b; /* bit buffer */
384 register unsigned k; /* number of bits in bit buffer */
386 /* make local copies of globals */
387 b = bb; /* initialize bit buffer */
389 w = outcnt; /* initialize window position */
391 /* inflate the coded data */
392 ml = mask_bits[bl]; /* precompute masks for speed */
394 for (;;) { /* do until end of block */
395 while (k < (unsigned) bl) {
396 b |= ((unsigned long)fgetc(in_file)) << k;
399 if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
408 b |= ((unsigned long)fgetc(in_file)) << k;
411 } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
414 if (e == 16) { /* then it's a literal */
415 window[w++] = (unsigned char) t->v.n;
421 } else { /* it's an EOB or a length */
423 /* exit if end of block */
428 /* get length of block to copy */
430 b |= ((unsigned long)fgetc(in_file)) << k;
433 n = t->v.n + ((unsigned) b & mask_bits[e]);
437 /* decode distance of block to copy */
438 while (k < (unsigned) bd) {
439 b |= ((unsigned long)fgetc(in_file)) << k;
443 if ((e = (t = td + ((unsigned) b & md))->e) > 16)
451 b |= ((unsigned long)fgetc(in_file)) << k;
454 } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
458 b |= ((unsigned long)fgetc(in_file)) << k;
461 d = w - t->v.n - ((unsigned) b & mask_bits[e]);
467 n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n : e);
468 #if !defined(NOMEMCPY) && !defined(DEBUG)
469 if (w - d >= e) { /* (this test assumes unsigned comparison) */
470 memcpy(window + w, window + d, e);
473 } else /* do it slow to avoid memcpy() overlap */
474 #endif /* !NOMEMCPY */
476 window[w++] = window[d++];
487 /* restore the globals from the locals */
488 outcnt = w; /* restore global window pointer */
489 bb = b; /* restore global bit buffer */
496 static const unsigned short cplens[] = { /* Copy lengths for literal codes 257..285 */
497 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
498 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
500 /* note: see note #13 above about the 258 in this list. */
501 static const extra_bits_t cplext[] = { /* Extra bits for literal codes 257..285 */
502 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
503 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
505 static const unsigned short cpdist[] = { /* Copy offsets for distance codes 0..29 */
506 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
507 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
508 8193, 12289, 16385, 24577
510 static const extra_bits_t cpdext[] = { /* Extra bits for distance codes */
511 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
512 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
515 /* Tables for deflate from PKZIP's appnote.txt. */
516 static const extra_bits_t border[] = { /* Order of the bit length code lengths */
517 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
521 * decompress an inflated block
524 * GLOBAL VARIABLES: bb, kk,
526 static int inflate_block(int *e)
528 unsigned t; /* block type */
529 register unsigned long b; /* bit buffer */
530 register unsigned k; /* number of bits in bit buffer */
532 /* make local bit buffer */
536 /* read in last block bit */
538 b |= ((unsigned long)fgetc(in_file)) << k;
545 /* read in block type */
547 b |= ((unsigned long)fgetc(in_file)) << k;
550 t = (unsigned) b & 3;
554 /* restore the global bit buffer */
558 /* inflate that block type */
560 case 0: /* Inflate stored */
562 unsigned long n; /* number of bytes in block */
563 unsigned long w; /* current window position */
564 register unsigned long b_stored; /* bit buffer */
565 register unsigned long k_stored; /* number of bits in bit buffer */
567 /* make local copies of globals */
568 b_stored = bb; /* initialize bit buffer */
570 w = outcnt; /* initialize window position */
572 /* go to byte boundary */
577 /* get the length and its complement */
578 while (k_stored < 16) {
579 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
582 n = ((unsigned) b_stored & 0xffff);
585 while (k_stored < 16) {
586 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
589 if (n != (unsigned) ((~b_stored) & 0xffff)) {
590 return 1; /* error in compressed data */
595 /* read and output the compressed data */
597 while (k_stored < 8) {
598 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
601 window[w++] = (unsigned char) b_stored;
602 if (w == (unsigned long)WSIZE) {
611 /* restore the globals from the locals */
612 outcnt = w; /* restore global window pointer */
613 bb = b_stored; /* restore global bit buffer */
617 case 1: /* Inflate fixed
618 * decompress an inflated type 1 (fixed Huffman codes) block. We should
619 * either replace this with a custom decoder, or at least precompute the
623 int i; /* temporary variable */
624 huft_t *tl; /* literal/length code table */
625 huft_t *td; /* distance code table */
626 int bl; /* lookup bits for tl */
627 int bd; /* lookup bits for td */
628 unsigned int l[288]; /* length list for huft_build */
630 /* set up literal table */
631 for (i = 0; i < 144; i++) {
634 for (; i < 256; i++) {
637 for (; i < 280; i++) {
640 for (; i < 288; i++) { /* make a complete, but wrong code set */
644 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
648 /* set up distance table */
649 for (i = 0; i < 30; i++) { /* make an incomplete code set */
653 if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
658 /* decompress until an end-of-block code */
659 if (inflate_codes(tl, td, bl, bd))
662 /* free the decoding tables, return */
667 case 2: /* Inflate dynamic */
669 const int dbits = 6; /* bits in base distance lookup table */
670 const int lbits = 9; /* bits in base literal/length lookup table */
672 int i; /* temporary variables */
674 unsigned l; /* last length */
675 unsigned m; /* mask for bit lengths table */
676 unsigned n; /* number of lengths to get */
677 huft_t *tl; /* literal/length code table */
678 huft_t *td; /* distance code table */
679 int bl; /* lookup bits for tl */
680 int bd; /* lookup bits for td */
681 unsigned nb; /* number of bit length codes */
682 unsigned nl; /* number of literal/length codes */
683 unsigned nd; /* number of distance codes */
685 unsigned ll[286 + 30]; /* literal/length and distance code lengths */
686 register unsigned long b_dynamic; /* bit buffer */
687 register unsigned k_dynamic; /* number of bits in bit buffer */
689 /* make local bit buffer */
693 /* read in table lengths */
694 while (k_dynamic < 5) {
695 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
698 nl = 257 + ((unsigned) b_dynamic & 0x1f); /* number of literal/length codes */
701 while (k_dynamic < 5) {
702 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
705 nd = 1 + ((unsigned) b_dynamic & 0x1f); /* number of distance codes */
708 while (k_dynamic < 4) {
709 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
712 nb = 4 + ((unsigned) b_dynamic & 0xf); /* number of bit length codes */
715 if (nl > 286 || nd > 30) {
716 return 1; /* bad lengths */
719 /* read in bit-length-code lengths */
720 for (j = 0; j < nb; j++) {
721 while (k_dynamic < 3) {
722 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
725 ll[border[j]] = (unsigned) b_dynamic & 7;
729 for (; j < 19; j++) {
733 /* build decoding table for trees--single level, 7 bit lookup */
735 if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
739 return i; /* incomplete code set */
742 /* read in literal and distance code lengths */
746 while ((unsigned) i < n) {
747 while (k_dynamic < (unsigned) bl) {
748 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
751 j = (td = tl + ((unsigned) b_dynamic & m))->b;
755 if (j < 16) { /* length of code in bits (0..15) */
756 ll[i++] = l = j; /* save last length in l */
758 else if (j == 16) { /* repeat last length 3 to 6 times */
759 while (k_dynamic < 2) {
760 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
763 j = 3 + ((unsigned) b_dynamic & 3);
766 if ((unsigned) i + j > n) {
772 } else if (j == 17) { /* 3 to 10 zero length codes */
773 while (k_dynamic < 3) {
774 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
777 j = 3 + ((unsigned) b_dynamic & 7);
780 if ((unsigned) i + j > n) {
787 } else { /* j == 18: 11 to 138 zero length codes */
788 while (k_dynamic < 7) {
789 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
792 j = 11 + ((unsigned) b_dynamic & 0x7f);
795 if ((unsigned) i + j > n) {
805 /* free decoding table for trees */
808 /* restore the global bit buffer */
812 /* build the decoding tables for literal/length and distance codes */
814 if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
816 error_msg("Incomplete literal tree");
819 return i; /* incomplete code set */
822 if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
824 error_msg("incomplete distance tree");
828 return i; /* incomplete code set */
831 /* decompress until an end-of-block code */
832 if (inflate_codes(tl, td, bl, bd))
835 /* free the decoding tables, return */
847 * decompress an inflated entry
849 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
851 extern int inflate(FILE *in, FILE *out)
853 int e; /* last block flag */
854 int r; /* result code */
855 unsigned h = 0; /* maximum struct huft's malloc'ed */
857 /* initialize window, bit buffer */
865 /* Allocate all global buffers (for DYN_ALLOC option) */
866 window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
869 /* Create the crc table */
872 /* decompress until the last block */
875 if ((r = inflate_block(&e)) != 0) {
883 /* Undo too much lookahead. The next read will be byte aligned so we
884 * can discard unused bits in the last meaningful byte.
888 ungetc((bb << bk), in_file);
891 /* flush out window */
900 /* ===========================================================================
901 * Unzip in to out. This routine works on gzip files only.
903 * IN assertions: the buffer inbuf contains already the beginning of
904 * the compressed data, from offsets inptr to insize-1 included.
905 * The magic header has already been checked. The output buffer is cleared.
906 * in, out: input and output file descriptors
908 extern int unzip(FILE *l_in_file, FILE *l_out_file)
910 unsigned char buf[8]; /* extended local header */
911 unsigned char flags; /* compression flags */
912 typedef void (*sig_type) (int);
915 if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
916 (void) signal(SIGINT, (sig_type) abort_gzip);
919 // if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
920 // (void) signal(SIGTERM, (sig_type) abort_gzip);
924 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
925 (void) signal(SIGHUP, (sig_type) abort_gzip);
929 /* Magic header for gzip files, 1F 8B = \037\213 */
930 if ((fgetc(l_in_file) != 0x1F) || (fgetc(l_in_file) != 0x8b)) {
931 error_msg("Invalid gzip magic");
935 /* Check the compression method */
936 if (fgetc(l_in_file) != 8) {
937 error_msg("Unknown compression method");
941 flags = (unsigned char) fgetc(l_in_file);
943 /* Ignore time stamp(4), extra flags(1), OS type(1) */
944 for (i = 0; i < 6; i++) {
949 /* bit 2 set: extra field present */
950 const unsigned short extra = fgetc(l_in_file) + (fgetc(l_in_file) << 8);
952 for (i = 0; i < extra; i++) {
957 /* Discard original name if any */
959 /* bit 3 set: original file name present */
960 while (fgetc(l_in_file) != 0); /* null */
963 /* Discard file comment if any */
965 /* bit 4 set: file comment present */
966 while (fgetc(l_in_file) != 0); /* null */
970 if (inflate(l_in_file, l_out_file) != 0) {
971 error_msg("invalid compressed data--format violated");
974 /* Get the crc and original length
975 * crc32 (see algorithm.doc)
976 * uncompressed input size modulo 2^32
978 fread(buf, 1, 8, l_in_file);
980 /* Validate decompression - crc */
981 if ((unsigned int)((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
982 error_msg("invalid compressed data--crc error");
984 /* Validate decompression - size */
985 if (((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
986 error_msg("invalid compressed data--length error");
993 * This needs access to global variables window and crc_table, so its not in its own file.
995 extern void gz_close(int gunzip_pid)
997 if (kill(gunzip_pid, SIGTERM) == -1) {
998 error_msg_and_die("*** Couldnt kill old gunzip process *** aborting");
1001 if (waitpid(gunzip_pid, NULL, 0) == -1) {
1002 printf("Couldnt wait ?");