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>
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 = 0xffffffffL; /* 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 crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long));
131 /* Compute and print table of CRC's, five per line */
132 for (i = 0; i < 256; i++) {
133 unsigned long table_entry; /* crc shift register */
134 char k; /* byte being shifted into crc apparatus */
137 /* The idea to initialize the register with the byte instead of
138 * zero was stolen from Haruhiko Okumura's ar002
140 for (k = 8; k; k--) {
141 table_entry = table_entry & 1 ? (table_entry >> 1) ^ poly : table_entry >> 1;
143 crc_table[i]=table_entry;
147 /* ===========================================================================
148 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
149 * (Used for the decompressed data only.)
151 static void flush_window(void)
158 for (n = 0; n < outcnt; n++) {
159 crc = crc_table[((int) crc ^ (window[n])) & 0xff] ^ (crc >> 8);
162 if (fwrite(window, 1, outcnt, out_file) != outcnt) {
163 error_msg_and_die("Couldnt write");
165 bytes_out += (unsigned long) outcnt;
170 * Free the malloc'ed tables built by huft_build(), which makes a linked
171 * list of the tables it made, with the links in a dummy first entry of
175 static int huft_free(huft_t *t)
179 /* Go through linked list, freeing from the malloced (t[-1]) address. */
181 while (p != (huft_t *) NULL) {
189 /* Given a list of code lengths and a maximum table size, make a set of
190 * tables to decode that set of codes. Return zero on success, one if
191 * the given code set is incomplete (the tables are still built in this
192 * case), two if the input is invalid (all zero length codes or an
193 * oversubscribed set of lengths), and three if not enough memory.
195 * b: code lengths in bits (all assumed <= BMAX)
196 * n: number of codes (assumed <= N_MAX)
197 * s: number of simple-valued codes (0..s-1)
198 * d: list of base values for non-simple codes
199 * e: list of extra bits for non-simple codes
200 * t: result: starting table
201 * m: maximum lookup bits, returns actual
203 static int huft_build(unsigned int *b, const unsigned int n, const unsigned int s,
204 const unsigned short *d, const unsigned short *e, huft_t **t, int *m)
206 unsigned a; /* counter for codes of length k */
207 unsigned c[BMAX + 1]; /* bit length count table */
208 unsigned f; /* i repeats in table every f entries */
209 int g; /* maximum code length */
210 int h; /* table level */
211 register unsigned i; /* counter, current code */
212 register unsigned j; /* counter */
213 register int k; /* number of bits in current code */
214 int l; /* bits per table (returned in m) */
215 register unsigned *p; /* pointer into c[], b[], or v[] */
216 register huft_t *q; /* points to current table */
217 huft_t r; /* table entry for structure assignment */
218 huft_t *u[BMAX]; /* table stack */
219 unsigned v[N_MAX]; /* values in order of bit length */
220 register int w; /* bits before this table == (l * h) */
221 unsigned x[BMAX + 1]; /* bit offsets, then code stack */
222 unsigned *xp; /* pointer into x */
223 int y; /* number of dummy codes added */
224 unsigned z; /* number of entries in current table */
226 /* Generate counts for each bit length */
227 memset ((void *)(c), 0, sizeof(c));
231 c[*p]++; /* assume all entries <= BMAX */
232 p++; /* Can't combine with above line (Solaris bug) */
234 if (c[0] == n) { /* null input--all zero length codes */
235 *t = (huft_t *) NULL;
240 /* Find minimum and maximum length, bound *m by those */
242 for (j = 1; j <= BMAX; j++)
245 k = j; /* minimum code length */
246 if ((unsigned) l < j)
248 for (i = BMAX; i; i--)
251 g = i; /* maximum code length */
252 if ((unsigned) l > i)
256 /* Adjust last length count to fill out codes, if needed */
257 for (y = 1 << j; j < i; j++, y <<= 1)
259 return 2; /* bad input: more codes than bits */
264 /* Generate starting offsets into the value table for each length */
268 while (--i) { /* note that i == g from above */
272 /* Make a table of values in order of bit lengths */
280 /* Generate the Huffman codes and for each, make the table entries */
281 x[0] = i = 0; /* first Huffman code is zero */
282 p = v; /* grab values in bit order */
283 h = -1; /* no tables yet--level -1 */
284 w = -l; /* bits decoded == (l * h) */
285 u[0] = (huft_t *) NULL; /* just to keep compilers happy */
286 q = (huft_t *) NULL; /* ditto */
289 /* go through the bit lengths (k already is bits in shortest code) */
290 for (; k <= g; k++) {
293 /* here i is the Huffman code of length k bits for value *p */
294 /* make tables up to required level */
297 w += l; /* previous table always l bits */
299 /* compute minimum size table less than or equal to l bits */
300 z = (z = g - w) > (unsigned) l ? l : z; /* upper limit on table size */
301 if ((f = 1 << (j = k - w)) > a + 1) { /* try a k-w bit table *//* too few codes for k-w bit table */
302 f -= a + 1; /* deduct codes from patterns left */
304 while (++j < z) { /* try smaller tables up to z bits */
305 if ((f <<= 1) <= *++xp)
306 break; /* enough codes to use up j bits */
307 f -= *xp; /* else deduct codes from patterns */
310 z = 1 << j; /* table entries for j-bit table */
312 /* allocate and link in new table */
313 q = (huft_t *) xmalloc((z + 1) * sizeof(huft_t));
315 hufts += z + 1; /* track memory usage */
316 *t = q + 1; /* link to list for huft_free() */
317 *(t = &(q->v.t)) = NULL;
318 u[h] = ++q; /* table starts after link */
320 /* connect to last table, if there is one */
322 x[h] = i; /* save pattern for backing up */
323 r.b = (unsigned char) l; /* bits to dump before this table */
324 r.e = (unsigned char) (16 + j); /* bits in this table */
325 r.v.t = q; /* pointer to this table */
326 j = i >> (w - l); /* (get around Turbo C bug) */
327 u[h - 1][j] = r; /* connect to last table */
331 /* set up table entry in r */
332 r.b = (unsigned char) (k - w);
334 r.e = 99; /* out of values--invalid code */
336 r.e = (unsigned char) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */
337 r.v.n = (unsigned short) (*p); /* simple code is just the value */
338 p++; /* one compiler does not like *p++ */
340 r.e = (unsigned char) e[*p - s]; /* non-simple--look up in lists */
344 /* fill code-like entries with r */
346 for (j = i >> w; j < z; j += f)
349 /* backwards increment the k-bit code i */
350 for (j = 1 << (k - 1); i & j; j >>= 1)
354 /* backup over finished tables */
355 while ((i & ((1 << w) - 1)) != x[h]) {
356 h--; /* don't need to update q */
361 /* Return true (1) if we were given an incomplete table */
362 return y != 0 && g != 1;
366 * inflate (decompress) the codes in a deflated (compressed) block.
367 * Return an error code or zero if it all goes ok.
369 * tl, td: literal/length and distance decoder tables
370 * bl, bd: number of bits decoded by tl[] and td[]
372 static int inflate_codes(huft_t *tl, huft_t *td, int bl, int bd)
374 register unsigned long e; /* table entry flag/number of extra bits */
375 unsigned long n, d; /* length and index for copy */
376 unsigned long w; /* current window position */
377 huft_t *t; /* pointer to table entry */
378 unsigned ml, md; /* masks for bl and bd bits */
379 register unsigned long b; /* bit buffer */
380 register unsigned k; /* number of bits in bit buffer */
382 /* make local copies of globals */
383 b = bb; /* initialize bit buffer */
385 w = outcnt; /* initialize window position */
387 /* inflate the coded data */
388 ml = mask_bits[bl]; /* precompute masks for speed */
390 for (;;) { /* do until end of block */
391 while (k < (unsigned) bl) {
392 b |= ((unsigned long)fgetc(in_file)) << k;
395 if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
404 b |= ((unsigned long)fgetc(in_file)) << k;
407 } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
410 if (e == 16) { /* then it's a literal */
411 window[w++] = (unsigned char) t->v.n;
417 } else { /* it's an EOB or a length */
419 /* exit if end of block */
424 /* get length of block to copy */
426 b |= ((unsigned long)fgetc(in_file)) << k;
429 n = t->v.n + ((unsigned) b & mask_bits[e]);
433 /* decode distance of block to copy */
434 while (k < (unsigned) bd) {
435 b |= ((unsigned long)fgetc(in_file)) << k;
439 if ((e = (t = td + ((unsigned) b & md))->e) > 16)
447 b |= ((unsigned long)fgetc(in_file)) << k;
450 } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
454 b |= ((unsigned long)fgetc(in_file)) << k;
457 d = w - t->v.n - ((unsigned) b & mask_bits[e]);
463 n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n : e);
464 #if !defined(NOMEMCPY) && !defined(DEBUG)
465 if (w - d >= e) { /* (this test assumes unsigned comparison) */
466 memcpy(window + w, window + d, e);
469 } else /* do it slow to avoid memcpy() overlap */
470 #endif /* !NOMEMCPY */
472 window[w++] = window[d++];
483 /* restore the globals from the locals */
484 outcnt = w; /* restore global window pointer */
485 bb = b; /* restore global bit buffer */
493 * decompress an inflated block
496 * GLOBAL VARIABLES: bb, kk,
498 static int inflate_block(int *e)
500 unsigned t; /* block type */
501 register unsigned long b; /* bit buffer */
502 register unsigned k; /* number of bits in bit buffer */
503 static unsigned short cplens[] = { /* Copy lengths for literal codes 257..285 */
504 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
505 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
507 /* note: see note #13 above about the 258 in this list. */
508 static unsigned short cplext[] = { /* Extra bits for literal codes 257..285 */
509 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
510 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
512 static unsigned short cpdist[] = { /* Copy offsets for distance codes 0..29 */
513 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
514 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
515 8193, 12289, 16385, 24577
517 static unsigned short cpdext[] = { /* Extra bits for distance codes */
518 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
519 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
523 /* make local bit buffer */
527 /* read in last block bit */
529 b |= ((unsigned long)fgetc(in_file)) << k;
536 /* read in block type */
538 b |= ((unsigned long)fgetc(in_file)) << k;
541 t = (unsigned) b & 3;
545 /* restore the global bit buffer */
549 /* inflate that block type */
551 case 0: /* Inflate stored */
553 unsigned long n; /* number of bytes in block */
554 unsigned long w; /* current window position */
555 register unsigned long b_stored; /* bit buffer */
556 register unsigned long k_stored; /* number of bits in bit buffer */
558 /* make local copies of globals */
559 b_stored = bb; /* initialize bit buffer */
561 w = outcnt; /* initialize window position */
563 /* go to byte boundary */
568 /* get the length and its complement */
569 while (k_stored < 16) {
570 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
573 n = ((unsigned) b_stored & 0xffff);
576 while (k_stored < 16) {
577 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
580 if (n != (unsigned) ((~b_stored) & 0xffff)) {
581 return 1; /* error in compressed data */
586 /* read and output the compressed data */
588 while (k_stored < 8) {
589 b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
592 window[w++] = (unsigned char) b_stored;
593 if (w == (unsigned long)WSIZE) {
602 /* restore the globals from the locals */
603 outcnt = w; /* restore global window pointer */
604 bb = b_stored; /* restore global bit buffer */
608 case 1: /* Inflate fixed
609 * decompress an inflated type 1 (fixed Huffman codes) block. We should
610 * either replace this with a custom decoder, or at least precompute the
614 int i; /* temporary variable */
615 huft_t *tl; /* literal/length code table */
616 huft_t *td; /* distance code table */
617 int bl; /* lookup bits for tl */
618 int bd; /* lookup bits for td */
619 unsigned int l[288]; /* length list for huft_build */
621 /* set up literal table */
622 for (i = 0; i < 144; i++) {
625 for (; i < 256; i++) {
628 for (; i < 280; i++) {
631 for (; i < 288; i++) { /* make a complete, but wrong code set */
635 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
639 /* set up distance table */
640 for (i = 0; i < 30; i++) { /* make an incomplete code set */
644 if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
649 /* decompress until an end-of-block code */
650 if (inflate_codes(tl, td, bl, bd))
653 /* free the decoding tables, return */
658 case 2: /* Inflate dynamic */
660 /* Tables for deflate from PKZIP's appnote.txt. */
661 static unsigned border[] = { /* Order of the bit length code lengths */
662 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
664 int dbits = 6; /* bits in base distance lookup table */
665 int lbits = 9; /* bits in base literal/length lookup table */
667 int i; /* temporary variables */
669 unsigned l; /* last length */
670 unsigned m; /* mask for bit lengths table */
671 unsigned n; /* number of lengths to get */
672 huft_t *tl; /* literal/length code table */
673 huft_t *td; /* distance code table */
674 int bl; /* lookup bits for tl */
675 int bd; /* lookup bits for td */
676 unsigned nb; /* number of bit length codes */
677 unsigned nl; /* number of literal/length codes */
678 unsigned nd; /* number of distance codes */
680 unsigned ll[286 + 30]; /* literal/length and distance code lengths */
681 register unsigned long b_dynamic; /* bit buffer */
682 register unsigned k_dynamic; /* number of bits in bit buffer */
684 /* make local bit buffer */
688 /* read in table lengths */
689 while (k_dynamic < 5) {
690 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
693 nl = 257 + ((unsigned) b_dynamic & 0x1f); /* number of literal/length codes */
696 while (k_dynamic < 5) {
697 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
700 nd = 1 + ((unsigned) b_dynamic & 0x1f); /* number of distance codes */
703 while (k_dynamic < 4) {
704 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
707 nb = 4 + ((unsigned) b_dynamic & 0xf); /* number of bit length codes */
710 if (nl > 286 || nd > 30) {
711 return 1; /* bad lengths */
714 /* read in bit-length-code lengths */
715 for (j = 0; j < nb; j++) {
716 while (k_dynamic < 3) {
717 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
720 ll[border[j]] = (unsigned) b_dynamic & 7;
724 for (; j < 19; j++) {
728 /* build decoding table for trees--single level, 7 bit lookup */
730 if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
734 return i; /* incomplete code set */
737 /* read in literal and distance code lengths */
741 while ((unsigned) i < n) {
742 while (k_dynamic < (unsigned) bl) {
743 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
746 j = (td = tl + ((unsigned) b_dynamic & m))->b;
750 if (j < 16) { /* length of code in bits (0..15) */
751 ll[i++] = l = j; /* save last length in l */
753 else if (j == 16) { /* repeat last length 3 to 6 times */
754 while (k_dynamic < 2) {
755 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
758 j = 3 + ((unsigned) b_dynamic & 3);
761 if ((unsigned) i + j > n) {
767 } else if (j == 17) { /* 3 to 10 zero length codes */
768 while (k_dynamic < 3) {
769 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
772 j = 3 + ((unsigned) b_dynamic & 7);
775 if ((unsigned) i + j > n) {
782 } else { /* j == 18: 11 to 138 zero length codes */
783 while (k_dynamic < 7) {
784 b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
787 j = 11 + ((unsigned) b_dynamic & 0x7f);
790 if ((unsigned) i + j > n) {
800 /* free decoding table for trees */
803 /* restore the global bit buffer */
807 /* build the decoding tables for literal/length and distance codes */
809 if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
811 error_msg("Incomplete literal tree");
814 return i; /* incomplete code set */
817 if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
819 error_msg("incomplete distance tree");
823 return i; /* incomplete code set */
826 /* decompress until an end-of-block code */
827 if (inflate_codes(tl, td, bl, bd))
830 /* free the decoding tables, return */
842 * decompress an inflated entry
844 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
846 static int inflate(void)
848 int e; /* last block flag */
849 int r; /* result code */
850 unsigned h = 0; /* maximum struct huft's malloc'ed */
852 /* initialize window, bit buffer */
857 /* Create the crc table */
860 /* decompress until the last block */
863 if ((r = inflate_block(&e)) != 0) {
871 /* Undo too much lookahead. The next read will be byte aligned so we
872 * can discard unused bits in the last meaningful byte.
876 ungetc((bb << bk), in_file);
879 /* flush out window */
886 /* ===========================================================================
887 * Unzip in to out. This routine works on both gzip and pkzip files.
889 * IN assertions: the buffer inbuf contains already the beginning of
890 * the compressed data, from offsets inptr to insize-1 included.
891 * The magic header has already been checked. The output buffer is cleared.
892 * in, out: input and output file descriptors
894 extern int unzip(FILE *l_in_file, FILE *l_out_file)
896 unsigned char buf[8]; /* extended local header */
897 unsigned char flags; /* compression flags */
898 typedef void (*sig_type) (int);
902 out_file = l_out_file;
904 if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
905 (void) signal(SIGINT, (sig_type) abort_gzip);
908 // if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
909 // (void) signal(SIGTERM, (sig_type) abort_gzip);
913 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
914 (void) signal(SIGHUP, (sig_type) abort_gzip);
918 /* Allocate all global buffers (for DYN_ALLOC option) */
919 window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
923 /* Magic header for gzip files, 1F 8B = \037\213 */
924 if ((fgetc(in_file) != 0x1F) || (fgetc(in_file) != 0x8b)) {
925 error_msg("Invalid gzip magic");
929 /* Check the compression method */
930 if (fgetc(in_file) != 8) {
931 error_msg("Unknown compression method");
935 flags = (unsigned char) fgetc(in_file);
937 /* Ignore time stamp(4), extra flags(1), OS type(1) */
938 for (i = 0; i < 6; i++) {
943 /* bit 2 set: extra field present */
944 const unsigned short extra = fgetc(in_file) + (fgetc(in_file) << 8);
946 for (i = 0; i < extra; i++) {
951 /* Discard original name if any */
953 /* bit 3 set: original file name present */
954 while (fgetc(in_file) != 0); /* null */
957 /* Discard file comment if any */
959 /* bit 4 set: file comment present */
960 while (fgetc(in_file) != 0); /* null */
964 if (inflate() != 0) {
965 error_msg("invalid compressed data--format violated");
968 /* Get the crc and original length
969 * crc32 (see algorithm.doc)
970 * uncompressed input size modulo 2^32
972 fread(buf, 1, 8, in_file);
974 /* Validate decompression - crc */
975 if ((unsigned int)((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
976 error_msg("invalid compressed data--crc error");
978 /* Validate decompression - size */
979 if (((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
980 error_msg("invalid compressed data--length error");
990 * This needs access to global variables wondow and crc_table, so its not in its own file.
992 extern void gz_close(int gunzip_pid)
994 if (kill(gunzip_pid, SIGTERM) == -1) {
995 error_msg_and_die("*** Couldnt kill old gunzip process *** aborting");
998 if (waitpid(gunzip_pid, NULL, 0) == -1) {
999 printf("Couldnt wait ?");