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
15 * standard 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.
43 #include <sys/types.h>
52 static FILE *in_file
, *out_file
;
54 /* these are freed by gz_close */
55 static unsigned char *window
;
56 static unsigned long *crc_table
= NULL
;
58 static unsigned long crc
; /* shift register contents */
60 /* Return codes from gzip */
61 static const int ERROR
= 1;
64 * window size--must be a power of two, and
65 * at least 32K for zip's deflate method
67 static const int WSIZE
= 0x8000;
69 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
70 static const int BMAX
= 16; /* maximum bit length of any code (16 for explode) */
71 static const int N_MAX
= 288; /* maximum number of codes in any set */
73 static long bytes_out
; /* number of output bytes */
74 static unsigned long outcnt
; /* bytes in output buffer */
76 static unsigned hufts
; /* track memory usage */
77 static unsigned long bb
; /* bit buffer */
78 static unsigned bk
; /* bits in bit buffer */
80 typedef struct huft_s
{
81 unsigned char e
; /* number of extra bits or operation */
82 unsigned char b
; /* number of bits in this code or subcode */
84 unsigned short n
; /* literal, length base, or distance base */
85 struct huft_s
*t
; /* pointer to next level of table */
89 static const unsigned short mask_bits
[] = {
91 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
92 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
95 //static int error_number = 0;
96 /* ========================================================================
97 * Signal and error handler.
100 static void abort_gzip()
102 error_msg("gzip aborted\n");
106 static void make_crc_table()
108 unsigned long table_entry
; /* crc shift register */
109 unsigned long poly
= 0; /* polynomial exclusive-or pattern */
110 int i
; /* counter for all possible eight bit values */
111 int k
; /* byte being shifted into crc apparatus */
113 /* terms of polynomial defining this crc (except x^32): */
114 static int p
[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
116 /* initial shift register value */
118 crc_table
= (unsigned long *) xmalloc(256 * sizeof(unsigned long));
120 /* Make exclusive-or pattern from polynomial (0xedb88320) */
121 for (i
= 0; i
< sizeof(p
)/sizeof(int); i
++)
122 poly
|= 1L << (31 - p
[i
]);
124 /* Compute and print table of CRC's, five per line */
125 for (i
= 0; i
< 256; i
++) {
127 /* The idea to initialize the register with the byte instead of
128 * zero was stolen from Haruhiko Okumura's ar002
130 for (k
= 8; k
; k
--) {
131 table_entry
= table_entry
& 1 ? (table_entry
>> 1) ^ poly
: table_entry
>> 1;
133 crc_table
[i
]=table_entry
;
137 /* ===========================================================================
138 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
139 * (Used for the decompressed data only.)
141 static void flush_window(void)
148 for (n
= 0; n
< outcnt
; n
++) {
149 crc
= crc_table
[((int) crc
^ (window
[n
])) & 0xff] ^ (crc
>> 8);
152 if (fwrite(window
, 1, outcnt
, out_file
) != outcnt
) {
154 * The Parent process may not be interested in all the data we have,
155 * in which case it will rudely close its end of the pipe and
156 * wait for us to exit.
161 error_msg("Couldnt write");
164 bytes_out
+= (unsigned long) outcnt
;
169 * Free the malloc'ed tables built by huft_build(), which makes a linked
170 * list of the tables it made, with the links in a dummy first entry of
174 static int huft_free(huft_t
*t
)
178 /* Go through linked list, freeing from the malloced (t[-1]) address. */
180 while (p
!= (huft_t
*) NULL
) {
188 /* Given a list of code lengths and a maximum table size, make a set of
189 * tables to decode that set of codes. Return zero on success, one if
190 * the given code set is incomplete (the tables are still built in this
191 * case), two if the input is invalid (all zero length codes or an
192 * oversubscribed set of lengths), and three if not enough memory.
194 * b: code lengths in bits (all assumed <= BMAX)
195 * n: number of codes (assumed <= N_MAX)
196 * s: number of simple-valued codes (0..s-1)
197 * d: list of base values for non-simple codes
198 * e: list of extra bits for non-simple codes
199 * t: result: starting table
200 * m: maximum lookup bits, returns actual
202 static int huft_build(unsigned int *b
, const unsigned int n
, const unsigned int s
,
203 const unsigned short *d
, const unsigned short *e
, huft_t
**t
, int *m
)
205 unsigned a
; /* counter for codes of length k */
206 unsigned c
[BMAX
+ 1]; /* bit length count table */
207 unsigned f
; /* i repeats in table every f entries */
208 int g
; /* maximum code length */
209 int h
; /* table level */
210 unsigned i
; /* counter, current code */
211 unsigned j
; /* counter */
212 int k
; /* number of bits in current code */
213 int l
; /* bits per table (returned in m) */
214 unsigned *p
; /* pointer into c[], b[], or v[] */
215 huft_t
*q
; /* points to current table */
216 huft_t r
; /* table entry for structure assignment */
217 huft_t
*u
[BMAX
]; /* table stack */
218 unsigned v
[N_MAX
]; /* values in order of bit length */
219 int w
; /* bits before this table == (l * h) */
220 unsigned x
[BMAX
+ 1]; /* bit offsets, then code stack */
221 unsigned *xp
; /* pointer into x */
222 int y
; /* number of dummy codes added */
223 unsigned z
; /* number of entries in current table */
225 /* Generate counts for each bit length */
226 memset ((void *)(c
), 0, sizeof(c
));
230 c
[*p
]++; /* assume all entries <= BMAX */
231 p
++; /* Can't combine with above line (Solaris bug) */
233 if (c
[0] == n
) { /* null input--all zero length codes */
234 *t
= (huft_t
*) NULL
;
239 /* Find minimum and maximum length, bound *m by those */
241 for (j
= 1; j
<= BMAX
; j
++)
244 k
= j
; /* minimum code length */
245 if ((unsigned) l
< j
)
247 for (i
= BMAX
; i
; i
--)
250 g
= i
; /* maximum code length */
251 if ((unsigned) l
> i
)
255 /* Adjust last length count to fill out codes, if needed */
256 for (y
= 1 << j
; j
< i
; j
++, y
<<= 1)
258 return 2; /* bad input: more codes than bits */
263 /* Generate starting offsets into the value table for each length */
267 while (--i
) { /* note that i == g from above */
271 /* Make a table of values in order of bit lengths */
279 /* Generate the Huffman codes and for each, make the table entries */
280 x
[0] = i
= 0; /* first Huffman code is zero */
281 p
= v
; /* grab values in bit order */
282 h
= -1; /* no tables yet--level -1 */
283 w
= -l
; /* bits decoded == (l * h) */
284 u
[0] = (huft_t
*) NULL
; /* just to keep compilers happy */
285 q
= (huft_t
*) NULL
; /* ditto */
288 /* go through the bit lengths (k already is bits in shortest code) */
289 for (; k
<= g
; k
++) {
292 /* here i is the Huffman code of length k bits for value *p */
293 /* make tables up to required level */
296 w
+= l
; /* previous table always l bits */
298 /* compute minimum size table less than or equal to l bits */
299 z
= (z
= g
- w
) > (unsigned) l
? l
: z
; /* upper limit on table size */
300 if ((f
= 1 << (j
= k
- w
)) > a
+ 1) { /* try a k-w bit table *//* too few codes for k-w bit table */
301 f
-= a
+ 1; /* deduct codes from patterns left */
303 while (++j
< z
) { /* try smaller tables up to z bits */
304 if ((f
<<= 1) <= *++xp
)
305 break; /* enough codes to use up j bits */
306 f
-= *xp
; /* else deduct codes from patterns */
309 z
= 1 << j
; /* table entries for j-bit table */
311 /* allocate and link in new table */
312 if ((q
= (huft_t
*) xmalloc((z
+ 1) * sizeof(huft_t
))) == NULL
) {
316 return 3; /* not enough memory */
318 hufts
+= z
+ 1; /* track memory usage */
319 *t
= q
+ 1; /* link to list for huft_free() */
320 *(t
= &(q
->v
.t
)) = NULL
;
321 u
[h
] = ++q
; /* table starts after link */
323 /* connect to last table, if there is one */
325 x
[h
] = i
; /* save pattern for backing up */
326 r
.b
= (unsigned char) l
; /* bits to dump before this table */
327 r
.e
= (unsigned char) (16 + j
); /* bits in this table */
328 r
.v
.t
= q
; /* pointer to this table */
329 j
= i
>> (w
- l
); /* (get around Turbo C bug) */
330 u
[h
- 1][j
] = r
; /* connect to last table */
334 /* set up table entry in r */
335 r
.b
= (unsigned char) (k
- w
);
337 r
.e
= 99; /* out of values--invalid code */
339 r
.e
= (unsigned char) (*p
< 256 ? 16 : 15); /* 256 is end-of-block code */
340 r
.v
.n
= (unsigned short) (*p
); /* simple code is just the value */
341 p
++; /* one compiler does not like *p++ */
343 r
.e
= (unsigned char) e
[*p
- s
]; /* non-simple--look up in lists */
347 /* fill code-like entries with r */
349 for (j
= i
>> w
; j
< z
; j
+= f
)
352 /* backwards increment the k-bit code i */
353 for (j
= 1 << (k
- 1); i
& j
; j
>>= 1)
357 /* backup over finished tables */
358 while ((i
& ((1 << w
) - 1)) != x
[h
]) {
359 h
--; /* don't need to update q */
364 /* Return true (1) if we were given an incomplete table */
365 return y
!= 0 && g
!= 1;
369 * inflate (decompress) the codes in a deflated (compressed) block.
370 * Return an error code or zero if it all goes ok.
372 * tl, td: literal/length and distance decoder tables
373 * bl, bd: number of bits decoded by tl[] and td[]
375 static int inflate_codes(huft_t
*tl
, huft_t
*td
, int bl
, int bd
)
377 unsigned long e
; /* table entry flag/number of extra bits */
378 unsigned long n
, d
; /* length and index for copy */
379 unsigned long w
; /* current window position */
380 huft_t
*t
; /* pointer to table entry */
381 unsigned ml
, md
; /* masks for bl and bd bits */
382 unsigned long b
; /* bit buffer */
383 unsigned k
; /* number of bits in bit buffer */
385 /* make local copies of globals */
386 b
= bb
; /* initialize bit buffer */
388 w
= outcnt
; /* initialize window position */
390 /* inflate the coded data */
391 ml
= mask_bits
[bl
]; /* precompute masks for speed */
393 for (;;) { /* do until end of block */
394 while (k
< (unsigned) bl
) {
395 b
|= ((unsigned long)fgetc(in_file
)) << k
;
398 if ((e
= (t
= tl
+ ((unsigned) b
& ml
))->e
) > 16)
407 b
|= ((unsigned long)fgetc(in_file
)) << k
;
410 } while ((e
= (t
= t
->v
.t
+ ((unsigned) b
& mask_bits
[e
]))->e
) > 16);
413 if (e
== 16) { /* then it's a literal */
414 window
[w
++] = (unsigned char) t
->v
.n
;
420 } else { /* it's an EOB or a length */
422 /* exit if end of block */
427 /* get length of block to copy */
429 b
|= ((unsigned long)fgetc(in_file
)) << k
;
432 n
= t
->v
.n
+ ((unsigned) b
& mask_bits
[e
]);
436 /* decode distance of block to copy */
437 while (k
< (unsigned) bd
) {
438 b
|= ((unsigned long)fgetc(in_file
)) << k
;
442 if ((e
= (t
= td
+ ((unsigned) b
& md
))->e
) > 16)
450 b
|= ((unsigned long)fgetc(in_file
)) << k
;
453 } while ((e
= (t
= t
->v
.t
+ ((unsigned) b
& mask_bits
[e
]))->e
) > 16);
457 b
|= ((unsigned long)fgetc(in_file
)) << k
;
460 d
= w
- t
->v
.n
- ((unsigned) b
& mask_bits
[e
]);
466 n
-= (e
= (e
= WSIZE
- ((d
&= WSIZE
- 1) > w
? d
: w
)) > n
? n
: e
);
467 #if !defined(NOMEMCPY) && !defined(DEBUG)
468 if (w
- d
>= e
) { /* (this test assumes unsigned comparison) */
469 memcpy(window
+ w
, window
+ d
, e
);
472 } else /* do it slow to avoid memcpy() overlap */
473 #endif /* !NOMEMCPY */
475 window
[w
++] = window
[d
++];
486 /* restore the globals from the locals */
487 outcnt
= w
; /* restore global window pointer */
488 bb
= b
; /* restore global bit buffer */
496 * decompress an inflated block
499 * GLOBAL VARIABLES: bb, kk,
501 static int inflate_block(int *e
)
503 unsigned t
; /* block type */
504 unsigned long b
; /* bit buffer */
505 unsigned k
; /* number of bits in bit buffer */
506 static unsigned short cplens
[] = { /* Copy lengths for literal codes 257..285 */
507 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
508 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
510 /* note: see note #13 above about the 258 in this list. */
511 static unsigned short cplext
[] = { /* Extra bits for literal codes 257..285 */
512 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
513 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
515 static unsigned short cpdist
[] = { /* Copy offsets for distance codes 0..29 */
516 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
517 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
518 8193, 12289, 16385, 24577
520 static unsigned short cpdext
[] = { /* Extra bits for distance codes */
521 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
522 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
526 /* make local bit buffer */
530 /* read in last block bit */
532 b
|= ((unsigned long)fgetc(in_file
)) << k
;
539 /* read in block type */
541 b
|= ((unsigned long)fgetc(in_file
)) << k
;
544 t
= (unsigned) b
& 3;
548 /* restore the global bit buffer */
552 /* inflate that block type */
554 case 0: /* Inflate stored */
556 unsigned long n
; /* number of bytes in block */
557 unsigned long w
; /* current window position */
558 unsigned long b_stored
; /* bit buffer */
559 unsigned long k_stored
; /* number of bits in bit buffer */
561 /* make local copies of globals */
562 b_stored
= bb
; /* initialize bit buffer */
564 w
= outcnt
; /* initialize window position */
566 /* go to byte boundary */
571 /* get the length and its complement */
572 while (k_stored
< 16) {
573 b_stored
|= ((unsigned long)fgetc(in_file
)) << k_stored
;
576 n
= ((unsigned) b_stored
& 0xffff);
579 while (k_stored
< 16) {
580 b_stored
|= ((unsigned long)fgetc(in_file
)) << k_stored
;
583 if (n
!= (unsigned) ((~b_stored
) & 0xffff)) {
584 return 1; /* error in compressed data */
589 /* read and output the compressed data */
591 while (k_stored
< 8) {
592 b_stored
|= ((unsigned long)fgetc(in_file
)) << k_stored
;
595 window
[w
++] = (unsigned char) b_stored
;
596 if (w
== (unsigned long)WSIZE
) {
605 /* restore the globals from the locals */
606 outcnt
= w
; /* restore global window pointer */
607 bb
= b_stored
; /* restore global bit buffer */
611 case 1: /* Inflate fixed
612 * decompress an inflated type 1 (fixed Huffman codes) block. We should
613 * either replace this with a custom decoder, or at least precompute the
617 int i
; /* temporary variable */
618 huft_t
*tl
; /* literal/length code table */
619 huft_t
*td
; /* distance code table */
620 int bl
; /* lookup bits for tl */
621 int bd
; /* lookup bits for td */
622 unsigned int l
[288]; /* length list for huft_build */
624 /* set up literal table */
625 for (i
= 0; i
< 144; i
++) {
628 for (; i
< 256; i
++) {
631 for (; i
< 280; i
++) {
634 for (; i
< 288; i
++) { /* make a complete, but wrong code set */
638 if ((i
= huft_build(l
, 288, 257, cplens
, cplext
, &tl
, &bl
)) != 0) {
642 /* set up distance table */
643 for (i
= 0; i
< 30; i
++) { /* make an incomplete code set */
647 if ((i
= huft_build(l
, 30, 0, cpdist
, cpdext
, &td
, &bd
)) > 1) {
652 /* decompress until an end-of-block code */
653 if (inflate_codes(tl
, td
, bl
, bd
)) {
659 /* free the decoding tables, return */
664 case 2: /* Inflate dynamic */
666 /* Tables for deflate from PKZIP's appnote.txt. */
667 static unsigned border
[] = { /* Order of the bit length code lengths */
668 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
670 int dbits
= 6; /* bits in base distance lookup table */
671 int lbits
= 9; /* bits in base literal/length lookup table */
673 int i
; /* temporary variables */
675 unsigned l
; /* last length */
676 unsigned m
; /* mask for bit lengths table */
677 unsigned n
; /* number of lengths to get */
678 huft_t
*tl
; /* literal/length code table */
679 huft_t
*td
; /* distance code table */
680 int bl
; /* lookup bits for tl */
681 int bd
; /* lookup bits for td */
682 unsigned nb
; /* number of bit length codes */
683 unsigned nl
; /* number of literal/length codes */
684 unsigned nd
; /* number of distance codes */
686 unsigned ll
[286 + 30]; /* literal/length and distance code lengths */
687 unsigned long b_dynamic
; /* bit buffer */
688 unsigned k_dynamic
; /* number of bits in bit buffer */
690 /* make local bit buffer */
694 /* read in table lengths */
695 while (k_dynamic
< 5) {
696 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
699 nl
= 257 + ((unsigned) b_dynamic
& 0x1f); /* number of literal/length codes */
702 while (k_dynamic
< 5) {
703 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
706 nd
= 1 + ((unsigned) b_dynamic
& 0x1f); /* number of distance codes */
709 while (k_dynamic
< 4) {
710 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
713 nb
= 4 + ((unsigned) b_dynamic
& 0xf); /* number of bit length codes */
716 if (nl
> 286 || nd
> 30) {
717 return 1; /* bad lengths */
720 /* read in bit-length-code lengths */
721 for (j
= 0; j
< nb
; j
++) {
722 while (k_dynamic
< 3) {
723 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
726 ll
[border
[j
]] = (unsigned) b_dynamic
& 7;
730 for (; j
< 19; j
++) {
734 /* build decoding table for trees--single level, 7 bit lookup */
736 if ((i
= huft_build(ll
, 19, 19, NULL
, NULL
, &tl
, &bl
)) != 0) {
740 return i
; /* incomplete code set */
743 /* read in literal and distance code lengths */
747 while ((unsigned) i
< n
) {
748 while (k_dynamic
< (unsigned) bl
) {
749 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
752 j
= (td
= tl
+ ((unsigned) b_dynamic
& m
))->b
;
756 if (j
< 16) { /* length of code in bits (0..15) */
757 ll
[i
++] = l
= j
; /* save last length in l */
759 else if (j
== 16) { /* repeat last length 3 to 6 times */
760 while (k_dynamic
< 2) {
761 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
764 j
= 3 + ((unsigned) b_dynamic
& 3);
767 if ((unsigned) i
+ j
> n
) {
773 } else if (j
== 17) { /* 3 to 10 zero length codes */
774 while (k_dynamic
< 3) {
775 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
778 j
= 3 + ((unsigned) b_dynamic
& 7);
781 if ((unsigned) i
+ j
> n
) {
788 } else { /* j == 18: 11 to 138 zero length codes */
789 while (k_dynamic
< 7) {
790 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
793 j
= 11 + ((unsigned) b_dynamic
& 0x7f);
796 if ((unsigned) i
+ j
> n
) {
806 /* free decoding table for trees */
809 /* restore the global bit buffer */
813 /* build the decoding tables for literal/length and distance codes */
815 if ((i
= huft_build(ll
, nl
, 257, cplens
, cplext
, &tl
, &bl
)) != 0) {
817 error_msg("Incomplete literal tree");
820 return i
; /* incomplete code set */
823 if ((i
= huft_build(ll
+ nl
, nd
, 0, cpdist
, cpdext
, &td
, &bd
)) != 0) {
825 error_msg("incomplete distance tree");
829 return i
; /* incomplete code set */
832 /* decompress until an end-of-block code */
833 if (inflate_codes(tl
, td
, bl
, bd
)) {
839 /* free the decoding tables, return */
851 * decompress an inflated entry
853 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
857 int e
; /* last block flag */
858 int r
; /* result code */
859 unsigned h
= 0; /* maximum struct huft's malloc'ed */
861 /* initialize window, bit buffer */
866 /* decompress until the last block */
869 if ((r
= inflate_block(&e
)) != 0) {
877 /* Undo too much lookahead. The next read will be byte aligned so we
878 * can discard unused bits in the last meaningful byte. */
881 ungetc((bb
<< bk
), in_file
);
884 /* flush out window */
891 /* ===========================================================================
892 * Unzip in to out. This routine works on both gzip and pkzip files.
894 * IN assertions: the buffer inbuf contains already the beginning of
895 * the compressed data, from offsets inptr to insize-1 included.
896 * The magic header has already been checked. The output buffer is cleared.
897 * in, out: input and output file descriptors
899 extern int unzip(FILE *l_in_file
, FILE *l_out_file
)
901 const int extra_field
= 0x04; /* bit 2 set: extra field present */
902 const int orig_name
= 0x08; /* bit 3 set: original file name present */
903 const int comment
= 0x10; /* bit 4 set: file comment present */
904 unsigned char buf
[8]; /* extended local header */
905 unsigned char flags
; /* compression flags */
906 char magic
[2]; /* magic header */
908 typedef void (*sig_type
) (int);
909 int exit_code
=0; /* program exit code */
913 out_file
= l_out_file
;
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 signal(SIGPIPE
, SIG_IGN
);
931 /* Allocate all global buffers (for DYN_ALLOC option) */
932 window
= xmalloc((size_t)(((2L*WSIZE
)+1L)*sizeof(unsigned char)));
936 magic
[0] = fgetc(in_file
);
937 magic
[1] = fgetc(in_file
);
939 /* Magic header for gzip files, 1F 8B = \037\213 */
940 if (memcmp(magic
, "\037\213", 2) != 0) {
941 error_msg("Invalid gzip magic");
945 method
= (int) fgetc(in_file
);
947 error_msg("unknown method %d -- get newer version of gzip", method
);
952 flags
= (unsigned char) fgetc(in_file
);
954 /* Ignore time stamp(4), extra flags(1), OS type(1) */
955 for (i
= 0; i
< 6; i
++)
958 if ((flags
& extra_field
) != 0) {
960 extra
= fgetc(in_file
);
961 extra
+= fgetc(in_file
) << 8;
963 for (i
= 0; i
< extra
; i
++)
967 /* Discard original name if any */
968 if ((flags
& orig_name
) != 0) {
969 while (fgetc(in_file
) != 0); /* null */
972 /* Discard file comment if any */
973 if ((flags
& comment
) != 0) {
974 while (fgetc(in_file
) != 0); /* null */
978 printf("it failed\n");
979 return(exit_code
); /* error message already emitted */
990 error_msg(memory_exhausted
);
992 } else if (res
!= 0) {
993 error_msg("invalid compressed data--format violated");
998 error_msg("internal error, invalid method");
1002 /* Get the crc and original length
1003 * crc32 (see algorithm.doc)
1004 * uncompressed input size modulo 2^32
1006 fread(buf
, 1, 8, in_file
);
1008 /* Validate decompression - crc */
1009 if (!exit_code
&& (unsigned int)((buf
[0] | (buf
[1] << 8)) |((buf
[2] | (buf
[3] << 8)) << 16)) != (crc
^ 0xffffffffL
)) {
1010 error_msg("invalid compressed data--crc error");
1013 /* Validate decompression - size */
1014 if (!exit_code
&& ((buf
[4] | (buf
[5] << 8)) |((buf
[6] | (buf
[7] << 8)) << 16)) != (unsigned long) bytes_out
) {
1015 error_msg("invalid compressed data--length error");