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>
51 static FILE *in_file
, *out_file
;
53 /* these are freed by gz_close */
54 static unsigned char *window
;
55 static unsigned long *crc_table
= NULL
;
57 static unsigned long crc
; /* shift register contents */
59 /* Return codes from gzip */
60 static const int ERROR
= 1;
63 * window size--must be a power of two, and
64 * at least 32K for zip's deflate method
66 static const int WSIZE
= 0x8000;
68 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
69 static const int BMAX
= 16; /* maximum bit length of any code (16 for explode) */
70 static const int N_MAX
= 288; /* maximum number of codes in any set */
72 static long bytes_out
; /* number of output bytes */
73 static unsigned long outcnt
; /* bytes in output buffer */
75 static unsigned hufts
; /* track memory usage */
76 static unsigned long bb
; /* bit buffer */
77 static unsigned bk
; /* bits in bit buffer */
79 typedef struct huft_s
{
80 unsigned char e
; /* number of extra bits or operation */
81 unsigned char b
; /* number of bits in this code or subcode */
83 unsigned short n
; /* literal, length base, or distance base */
84 struct huft_s
*t
; /* pointer to next level of table */
88 static const unsigned short mask_bits
[] = {
90 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
91 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
94 //static int error_number = 0;
95 /* ========================================================================
96 * Signal and error handler.
99 static void abort_gzip()
101 error_msg("gzip aborted\n");
105 static void make_crc_table()
107 unsigned long table_entry
; /* crc shift register */
108 unsigned long poly
= 0; /* polynomial exclusive-or pattern */
109 int i
; /* counter for all possible eight bit values */
110 int k
; /* byte being shifted into crc apparatus */
112 /* terms of polynomial defining this crc (except x^32): */
113 static int p
[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
115 /* initial shift register value */
117 crc_table
= (unsigned long *) xmalloc(256 * sizeof(unsigned long));
119 /* Make exclusive-or pattern from polynomial (0xedb88320) */
120 for (i
= 0; i
< sizeof(p
)/sizeof(int); i
++)
121 poly
|= 1L << (31 - p
[i
]);
123 /* Compute and print table of CRC's, five per line */
124 for (i
= 0; i
< 256; i
++) {
126 /* The idea to initialize the register with the byte instead of
127 * zero was stolen from Haruhiko Okumura's ar002
129 for (k
= 8; k
; k
--) {
130 table_entry
= table_entry
& 1 ? (table_entry
>> 1) ^ poly
: table_entry
>> 1;
132 crc_table
[i
]=table_entry
;
136 /* ===========================================================================
137 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
138 * (Used for the decompressed data only.)
140 static void flush_window(void)
147 for (n
= 0; n
< outcnt
; n
++) {
148 crc
= crc_table
[((int) crc
^ (window
[n
])) & 0xff] ^ (crc
>> 8);
151 if (fwrite(window
, 1, outcnt
, out_file
) != outcnt
) {
152 error_msg("Couldnt write");
155 bytes_out
+= (unsigned long) outcnt
;
160 * Free the malloc'ed tables built by huft_build(), which makes a linked
161 * list of the tables it made, with the links in a dummy first entry of
165 static int huft_free(huft_t
*t
)
169 /* Go through linked list, freeing from the malloced (t[-1]) address. */
171 while (p
!= (huft_t
*) NULL
) {
179 /* Given a list of code lengths and a maximum table size, make a set of
180 * tables to decode that set of codes. Return zero on success, one if
181 * the given code set is incomplete (the tables are still built in this
182 * case), two if the input is invalid (all zero length codes or an
183 * oversubscribed set of lengths), and three if not enough memory.
185 * b: code lengths in bits (all assumed <= BMAX)
186 * n: number of codes (assumed <= N_MAX)
187 * s: number of simple-valued codes (0..s-1)
188 * d: list of base values for non-simple codes
189 * e: list of extra bits for non-simple codes
190 * t: result: starting table
191 * m: maximum lookup bits, returns actual
193 static int huft_build(unsigned int *b
, const unsigned int n
, const unsigned int s
,
194 const unsigned short *d
, const unsigned short *e
, huft_t
**t
, int *m
)
196 unsigned a
; /* counter for codes of length k */
197 unsigned c
[BMAX
+ 1]; /* bit length count table */
198 unsigned f
; /* i repeats in table every f entries */
199 int g
; /* maximum code length */
200 int h
; /* table level */
201 unsigned i
; /* counter, current code */
202 unsigned j
; /* counter */
203 int k
; /* number of bits in current code */
204 int l
; /* bits per table (returned in m) */
205 unsigned *p
; /* pointer into c[], b[], or v[] */
206 huft_t
*q
; /* points to current table */
207 huft_t r
; /* table entry for structure assignment */
208 huft_t
*u
[BMAX
]; /* table stack */
209 unsigned v
[N_MAX
]; /* values in order of bit length */
210 int w
; /* bits before this table == (l * h) */
211 unsigned x
[BMAX
+ 1]; /* bit offsets, then code stack */
212 unsigned *xp
; /* pointer into x */
213 int y
; /* number of dummy codes added */
214 unsigned z
; /* number of entries in current table */
216 /* Generate counts for each bit length */
217 memset ((void *)(c
), 0, sizeof(c
));
221 c
[*p
]++; /* assume all entries <= BMAX */
222 p
++; /* Can't combine with above line (Solaris bug) */
224 if (c
[0] == n
) { /* null input--all zero length codes */
225 *t
= (huft_t
*) NULL
;
230 /* Find minimum and maximum length, bound *m by those */
232 for (j
= 1; j
<= BMAX
; j
++)
235 k
= j
; /* minimum code length */
236 if ((unsigned) l
< j
)
238 for (i
= BMAX
; i
; i
--)
241 g
= i
; /* maximum code length */
242 if ((unsigned) l
> i
)
246 /* Adjust last length count to fill out codes, if needed */
247 for (y
= 1 << j
; j
< i
; j
++, y
<<= 1)
249 return 2; /* bad input: more codes than bits */
254 /* Generate starting offsets into the value table for each length */
258 while (--i
) { /* note that i == g from above */
262 /* Make a table of values in order of bit lengths */
270 /* Generate the Huffman codes and for each, make the table entries */
271 x
[0] = i
= 0; /* first Huffman code is zero */
272 p
= v
; /* grab values in bit order */
273 h
= -1; /* no tables yet--level -1 */
274 w
= -l
; /* bits decoded == (l * h) */
275 u
[0] = (huft_t
*) NULL
; /* just to keep compilers happy */
276 q
= (huft_t
*) NULL
; /* ditto */
279 /* go through the bit lengths (k already is bits in shortest code) */
280 for (; k
<= g
; k
++) {
283 /* here i is the Huffman code of length k bits for value *p */
284 /* make tables up to required level */
287 w
+= l
; /* previous table always l bits */
289 /* compute minimum size table less than or equal to l bits */
290 z
= (z
= g
- w
) > (unsigned) l
? l
: z
; /* upper limit on table size */
291 if ((f
= 1 << (j
= k
- w
)) > a
+ 1) { /* try a k-w bit table *//* too few codes for k-w bit table */
292 f
-= a
+ 1; /* deduct codes from patterns left */
294 while (++j
< z
) { /* try smaller tables up to z bits */
295 if ((f
<<= 1) <= *++xp
)
296 break; /* enough codes to use up j bits */
297 f
-= *xp
; /* else deduct codes from patterns */
300 z
= 1 << j
; /* table entries for j-bit table */
302 /* allocate and link in new table */
303 if ((q
= (huft_t
*) xmalloc((z
+ 1) * sizeof(huft_t
))) == NULL
) {
307 return 3; /* not enough memory */
309 hufts
+= z
+ 1; /* track memory usage */
310 *t
= q
+ 1; /* link to list for huft_free() */
311 *(t
= &(q
->v
.t
)) = NULL
;
312 u
[h
] = ++q
; /* table starts after link */
314 /* connect to last table, if there is one */
316 x
[h
] = i
; /* save pattern for backing up */
317 r
.b
= (unsigned char) l
; /* bits to dump before this table */
318 r
.e
= (unsigned char) (16 + j
); /* bits in this table */
319 r
.v
.t
= q
; /* pointer to this table */
320 j
= i
>> (w
- l
); /* (get around Turbo C bug) */
321 u
[h
- 1][j
] = r
; /* connect to last table */
325 /* set up table entry in r */
326 r
.b
= (unsigned char) (k
- w
);
328 r
.e
= 99; /* out of values--invalid code */
330 r
.e
= (unsigned char) (*p
< 256 ? 16 : 15); /* 256 is end-of-block code */
331 r
.v
.n
= (unsigned short) (*p
); /* simple code is just the value */
332 p
++; /* one compiler does not like *p++ */
334 r
.e
= (unsigned char) e
[*p
- s
]; /* non-simple--look up in lists */
338 /* fill code-like entries with r */
340 for (j
= i
>> w
; j
< z
; j
+= f
)
343 /* backwards increment the k-bit code i */
344 for (j
= 1 << (k
- 1); i
& j
; j
>>= 1)
348 /* backup over finished tables */
349 while ((i
& ((1 << w
) - 1)) != x
[h
]) {
350 h
--; /* don't need to update q */
355 /* Return true (1) if we were given an incomplete table */
356 return y
!= 0 && g
!= 1;
360 * inflate (decompress) the codes in a deflated (compressed) block.
361 * Return an error code or zero if it all goes ok.
363 * tl, td: literal/length and distance decoder tables
364 * bl, bd: number of bits decoded by tl[] and td[]
366 static int inflate_codes(huft_t
*tl
, huft_t
*td
, int bl
, int bd
)
368 unsigned long e
; /* table entry flag/number of extra bits */
369 unsigned long n
, d
; /* length and index for copy */
370 unsigned long w
; /* current window position */
371 huft_t
*t
; /* pointer to table entry */
372 unsigned ml
, md
; /* masks for bl and bd bits */
373 unsigned long b
; /* bit buffer */
374 unsigned k
; /* number of bits in bit buffer */
376 /* make local copies of globals */
377 b
= bb
; /* initialize bit buffer */
379 w
= outcnt
; /* initialize window position */
381 /* inflate the coded data */
382 ml
= mask_bits
[bl
]; /* precompute masks for speed */
384 for (;;) { /* do until end of block */
385 while (k
< (unsigned) bl
) {
386 b
|= ((unsigned long)fgetc(in_file
)) << k
;
389 if ((e
= (t
= tl
+ ((unsigned) b
& ml
))->e
) > 16)
398 b
|= ((unsigned long)fgetc(in_file
)) << k
;
401 } while ((e
= (t
= t
->v
.t
+ ((unsigned) b
& mask_bits
[e
]))->e
) > 16);
404 if (e
== 16) { /* then it's a literal */
405 window
[w
++] = (unsigned char) t
->v
.n
;
411 } else { /* it's an EOB or a length */
413 /* exit if end of block */
418 /* get length of block to copy */
420 b
|= ((unsigned long)fgetc(in_file
)) << k
;
423 n
= t
->v
.n
+ ((unsigned) b
& mask_bits
[e
]);
427 /* decode distance of block to copy */
428 while (k
< (unsigned) bd
) {
429 b
|= ((unsigned long)fgetc(in_file
)) << k
;
433 if ((e
= (t
= td
+ ((unsigned) b
& md
))->e
) > 16)
441 b
|= ((unsigned long)fgetc(in_file
)) << k
;
444 } while ((e
= (t
= t
->v
.t
+ ((unsigned) b
& mask_bits
[e
]))->e
) > 16);
448 b
|= ((unsigned long)fgetc(in_file
)) << k
;
451 d
= w
- t
->v
.n
- ((unsigned) b
& mask_bits
[e
]);
457 n
-= (e
= (e
= WSIZE
- ((d
&= WSIZE
- 1) > w
? d
: w
)) > n
? n
: e
);
458 #if !defined(NOMEMCPY) && !defined(DEBUG)
459 if (w
- d
>= e
) { /* (this test assumes unsigned comparison) */
460 memcpy(window
+ w
, window
+ d
, e
);
463 } else /* do it slow to avoid memcpy() overlap */
464 #endif /* !NOMEMCPY */
466 window
[w
++] = window
[d
++];
477 /* restore the globals from the locals */
478 outcnt
= w
; /* restore global window pointer */
479 bb
= b
; /* restore global bit buffer */
487 * decompress an inflated block
490 * GLOBAL VARIABLES: bb, kk,
492 static int inflate_block(int *e
)
494 unsigned t
; /* block type */
495 unsigned long b
; /* bit buffer */
496 unsigned k
; /* number of bits in bit buffer */
497 static unsigned short cplens
[] = { /* Copy lengths for literal codes 257..285 */
498 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
499 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
501 /* note: see note #13 above about the 258 in this list. */
502 static unsigned short cplext
[] = { /* Extra bits for literal codes 257..285 */
503 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
504 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
506 static unsigned short cpdist
[] = { /* Copy offsets for distance codes 0..29 */
507 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
508 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
509 8193, 12289, 16385, 24577
511 static unsigned short cpdext
[] = { /* Extra bits for distance codes */
512 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
513 7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
517 /* make local bit buffer */
521 /* read in last block bit */
523 b
|= ((unsigned long)fgetc(in_file
)) << k
;
530 /* read in block type */
532 b
|= ((unsigned long)fgetc(in_file
)) << k
;
535 t
= (unsigned) b
& 3;
539 /* restore the global bit buffer */
543 /* inflate that block type */
545 case 0: /* Inflate stored */
547 unsigned long n
; /* number of bytes in block */
548 unsigned long w
; /* current window position */
549 unsigned long b_stored
; /* bit buffer */
550 unsigned long k_stored
; /* number of bits in bit buffer */
552 /* make local copies of globals */
553 b_stored
= bb
; /* initialize bit buffer */
555 w
= outcnt
; /* initialize window position */
557 /* go to byte boundary */
562 /* get the length and its complement */
563 while (k_stored
< 16) {
564 b_stored
|= ((unsigned long)fgetc(in_file
)) << k_stored
;
567 n
= ((unsigned) b_stored
& 0xffff);
570 while (k_stored
< 16) {
571 b_stored
|= ((unsigned long)fgetc(in_file
)) << k_stored
;
574 if (n
!= (unsigned) ((~b_stored
) & 0xffff)) {
575 return 1; /* error in compressed data */
580 /* read and output the compressed data */
582 while (k_stored
< 8) {
583 b_stored
|= ((unsigned long)fgetc(in_file
)) << k_stored
;
586 window
[w
++] = (unsigned char) b_stored
;
587 if (w
== (unsigned long)WSIZE
) {
596 /* restore the globals from the locals */
597 outcnt
= w
; /* restore global window pointer */
598 bb
= b_stored
; /* restore global bit buffer */
602 case 1: /* Inflate fixed
603 * decompress an inflated type 1 (fixed Huffman codes) block. We should
604 * either replace this with a custom decoder, or at least precompute the
608 int i
; /* temporary variable */
609 huft_t
*tl
; /* literal/length code table */
610 huft_t
*td
; /* distance code table */
611 int bl
; /* lookup bits for tl */
612 int bd
; /* lookup bits for td */
613 unsigned int l
[288]; /* length list for huft_build */
615 /* set up literal table */
616 for (i
= 0; i
< 144; i
++) {
619 for (; i
< 256; i
++) {
622 for (; i
< 280; i
++) {
625 for (; i
< 288; i
++) { /* make a complete, but wrong code set */
629 if ((i
= huft_build(l
, 288, 257, cplens
, cplext
, &tl
, &bl
)) != 0) {
633 /* set up distance table */
634 for (i
= 0; i
< 30; i
++) { /* make an incomplete code set */
638 if ((i
= huft_build(l
, 30, 0, cpdist
, cpdext
, &td
, &bd
)) > 1) {
643 /* decompress until an end-of-block code */
644 if (inflate_codes(tl
, td
, bl
, bd
)) {
650 /* free the decoding tables, return */
655 case 2: /* Inflate dynamic */
657 /* Tables for deflate from PKZIP's appnote.txt. */
658 static unsigned border
[] = { /* Order of the bit length code lengths */
659 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
661 int dbits
= 6; /* bits in base distance lookup table */
662 int lbits
= 9; /* bits in base literal/length lookup table */
664 int i
; /* temporary variables */
666 unsigned l
; /* last length */
667 unsigned m
; /* mask for bit lengths table */
668 unsigned n
; /* number of lengths to get */
669 huft_t
*tl
; /* literal/length code table */
670 huft_t
*td
; /* distance code table */
671 int bl
; /* lookup bits for tl */
672 int bd
; /* lookup bits for td */
673 unsigned nb
; /* number of bit length codes */
674 unsigned nl
; /* number of literal/length codes */
675 unsigned nd
; /* number of distance codes */
677 unsigned ll
[286 + 30]; /* literal/length and distance code lengths */
678 unsigned long b_dynamic
; /* bit buffer */
679 unsigned k_dynamic
; /* number of bits in bit buffer */
681 /* make local bit buffer */
685 /* read in table lengths */
686 while (k_dynamic
< 5) {
687 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
690 nl
= 257 + ((unsigned) b_dynamic
& 0x1f); /* number of literal/length codes */
693 while (k_dynamic
< 5) {
694 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
697 nd
= 1 + ((unsigned) b_dynamic
& 0x1f); /* number of distance codes */
700 while (k_dynamic
< 4) {
701 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
704 nb
= 4 + ((unsigned) b_dynamic
& 0xf); /* number of bit length codes */
707 if (nl
> 286 || nd
> 30) {
708 return 1; /* bad lengths */
711 /* read in bit-length-code lengths */
712 for (j
= 0; j
< nb
; j
++) {
713 while (k_dynamic
< 3) {
714 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
717 ll
[border
[j
]] = (unsigned) b_dynamic
& 7;
721 for (; j
< 19; j
++) {
725 /* build decoding table for trees--single level, 7 bit lookup */
727 if ((i
= huft_build(ll
, 19, 19, NULL
, NULL
, &tl
, &bl
)) != 0) {
731 return i
; /* incomplete code set */
734 /* read in literal and distance code lengths */
738 while ((unsigned) i
< n
) {
739 while (k_dynamic
< (unsigned) bl
) {
740 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
743 j
= (td
= tl
+ ((unsigned) b_dynamic
& m
))->b
;
747 if (j
< 16) { /* length of code in bits (0..15) */
748 ll
[i
++] = l
= j
; /* save last length in l */
750 else if (j
== 16) { /* repeat last length 3 to 6 times */
751 while (k_dynamic
< 2) {
752 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
755 j
= 3 + ((unsigned) b_dynamic
& 3);
758 if ((unsigned) i
+ j
> n
) {
764 } else if (j
== 17) { /* 3 to 10 zero length codes */
765 while (k_dynamic
< 3) {
766 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
769 j
= 3 + ((unsigned) b_dynamic
& 7);
772 if ((unsigned) i
+ j
> n
) {
779 } else { /* j == 18: 11 to 138 zero length codes */
780 while (k_dynamic
< 7) {
781 b_dynamic
|= ((unsigned long)fgetc(in_file
)) << k_dynamic
;
784 j
= 11 + ((unsigned) b_dynamic
& 0x7f);
787 if ((unsigned) i
+ j
> n
) {
797 /* free decoding table for trees */
800 /* restore the global bit buffer */
804 /* build the decoding tables for literal/length and distance codes */
806 if ((i
= huft_build(ll
, nl
, 257, cplens
, cplext
, &tl
, &bl
)) != 0) {
808 error_msg("Incomplete literal tree");
811 return i
; /* incomplete code set */
814 if ((i
= huft_build(ll
+ nl
, nd
, 0, cpdist
, cpdext
, &td
, &bd
)) != 0) {
816 error_msg("incomplete distance tree");
820 return i
; /* incomplete code set */
823 /* decompress until an end-of-block code */
824 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
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 /* decompress until the last block */
860 if ((r
= inflate_block(&e
)) != 0) {
868 /* Undo too much lookahead. The next read will be byte aligned so we
869 * can discard unused bits in the last meaningful byte. */
872 ungetc((bb
<< bk
), in_file
);
875 /* flush out window */
882 /* ===========================================================================
883 * Unzip in to out. This routine works on both gzip and pkzip files.
885 * IN assertions: the buffer inbuf contains already the beginning of
886 * the compressed data, from offsets inptr to insize-1 included.
887 * The magic header has already been checked. The output buffer is cleared.
888 * in, out: input and output file descriptors
890 extern int unzip(FILE *l_in_file
, FILE *l_out_file
)
892 const int extra_field
= 0x04; /* bit 2 set: extra field present */
893 const int orig_name
= 0x08; /* bit 3 set: original file name present */
894 const int comment
= 0x10; /* bit 4 set: file comment present */
895 unsigned char buf
[8]; /* extended local header */
896 unsigned char flags
; /* compression flags */
897 char magic
[2]; /* magic header */
899 typedef void (*sig_type
) (int);
900 int exit_code
=0; /* program exit code */
904 out_file
= l_out_file
;
906 if (signal(SIGINT
, SIG_IGN
) != SIG_IGN
) {
907 (void) signal(SIGINT
, (sig_type
) abort_gzip
);
910 // if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
911 // (void) signal(SIGTERM, (sig_type) abort_gzip);
915 if (signal(SIGHUP
, SIG_IGN
) != SIG_IGN
) {
916 (void) signal(SIGHUP
, (sig_type
) abort_gzip
);
920 /* Allocate all global buffers (for DYN_ALLOC option) */
921 window
= xmalloc((size_t)(((2L*WSIZE
)+1L)*sizeof(unsigned char)));
925 magic
[0] = fgetc(in_file
);
926 magic
[1] = fgetc(in_file
);
928 /* Magic header for gzip files, 1F 8B = \037\213 */
929 if (memcmp(magic
, "\037\213", 2) != 0) {
930 error_msg("Invalid gzip magic");
934 method
= (int) fgetc(in_file
);
936 error_msg("unknown method %d -- get newer version of gzip", method
);
941 flags
= (unsigned char) fgetc(in_file
);
943 /* Ignore time stamp(4), extra flags(1), OS type(1) */
944 for (i
= 0; i
< 6; i
++)
947 if ((flags
& extra_field
) != 0) {
949 extra
= fgetc(in_file
);
950 extra
+= fgetc(in_file
) << 8;
952 for (i
= 0; i
< extra
; i
++)
956 /* Discard original name if any */
957 if ((flags
& orig_name
) != 0) {
958 while (fgetc(in_file
) != 0); /* null */
961 /* Discard file comment if any */
962 if ((flags
& comment
) != 0) {
963 while (fgetc(in_file
) != 0); /* null */
967 printf("it failed\n");
968 return(exit_code
); /* error message already emitted */
979 error_msg(memory_exhausted
);
981 } else if (res
!= 0) {
982 error_msg("invalid compressed data--format violated");
987 error_msg("internal error, invalid method");
991 /* Get the crc and original length
992 * crc32 (see algorithm.doc)
993 * uncompressed input size modulo 2^32
995 fread(buf
, 1, 8, in_file
);
997 /* Validate decompression - crc */
998 if (!exit_code
&& (unsigned int)((buf
[0] | (buf
[1] << 8)) |((buf
[2] | (buf
[3] << 8)) << 16)) != (crc
^ 0xffffffffL
)) {
999 error_msg("invalid compressed data--crc error");
1002 /* Validate decompression - size */
1003 if (!exit_code
&& ((buf
[4] | (buf
[5] << 8)) |((buf
[6] | (buf
[7] << 8)) << 16)) != (unsigned long) bytes_out
) {
1004 error_msg("invalid compressed data--length error");