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hush/libbb/unzip.c
Glenn L McGrath 87ac7028e0 unzip applet by Laurence Anderson 
----------------------------------------------------------------------
2002-01-02 13:52:26 +00:00

1006 lines
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/* vi: set sw=4 ts=4: */
/*
* gunzip implementation for busybox
*
* Based on GNU gzip v1.2.4 Copyright (C) 1992-1993 Jean-loup Gailly.
*
* Originally adjusted for busybox by Sven Rudolph <sr1@inf.tu-dresden.de>
* based on gzip sources
*
* Adjusted further by Erik Andersen <andersee@debian.org> to support
* files as well as stdin/stdout, and to generally behave itself wrt
* command line handling.
*
* General cleanup to better adhere to the style guide and make use of standard
* busybox functions by Glenn McGrath <bug1@optushome.com.au>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
* gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
* Copyright (C) 1992-1993 Jean-loup Gailly
* The unzip code was written and put in the public domain by Mark Adler.
* Portions of the lzw code are derived from the public domain 'compress'
* written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
* Ken Turkowski, Dave Mack and Peter Jannesen.
*
* See the license_msg below and the file COPYING for the software license.
* See the file algorithm.doc for the compression algorithms and file formats.
*/
#if 0
static char *license_msg[] = {
" Copyright (C) 1992-1993 Jean-loup Gailly",
" This program is free software; you can redistribute it and/or modify",
" it under the terms of the GNU General Public License as published by",
" the Free Software Foundation; either version 2, or (at your option)",
" any later version.",
"",
" This program is distributed in the hope that it will be useful,",
" but WITHOUT ANY WARRANTY; without even the implied warranty of",
" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the",
" GNU General Public License for more details.",
"",
" You should have received a copy of the GNU General Public License",
" along with this program; if not, write to the Free Software",
" Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.",
0
};
#endif
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include "libbb.h"
static FILE *in_file, *out_file;
/* these are freed by gz_close */
static unsigned char *window;
static unsigned long *crc_table;
static unsigned long crc = 0xffffffffL; /* shift register contents */
/* Return codes from gzip */
static const int ERROR = 1;
/*
* window size--must be a power of two, and
* at least 32K for zip's deflate method
*/
static const int WSIZE = 0x8000;
/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
static const int BMAX = 16; /* maximum bit length of any code (16 for explode) */
static const int N_MAX = 288; /* maximum number of codes in any set */
static long bytes_out; /* number of output bytes */
static unsigned long outcnt; /* bytes in output buffer */
static unsigned hufts; /* track memory usage */
static unsigned long bb; /* bit buffer */
static unsigned bk; /* bits in bit buffer */
typedef struct huft_s {
unsigned char e; /* number of extra bits or operation */
unsigned char b; /* number of bits in this code or subcode */
union {
unsigned short n; /* literal, length base, or distance base */
struct huft_s *t; /* pointer to next level of table */
} v;
} huft_t;
static const unsigned short mask_bits[] = {
0x0000,
0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};
//static int error_number = 0;
/* ========================================================================
* Signal and error handler.
*/
static void abort_gzip(void)
{
error_msg("gzip aborted\n");
exit(ERROR);
}
static void make_crc_table(void)
{
const unsigned long poly = 0xedb88320; /* polynomial exclusive-or pattern */
unsigned short i; /* counter for all possible eight bit values */
crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long));
/* Compute and print table of CRC's, five per line */
for (i = 0; i < 256; i++) {
unsigned long table_entry; /* crc shift register */
char k; /* byte being shifted into crc apparatus */
table_entry = i;
/* The idea to initialize the register with the byte instead of
* zero was stolen from Haruhiko Okumura's ar002
*/
for (k = 8; k; k--) {
table_entry = table_entry & 1 ? (table_entry >> 1) ^ poly : table_entry >> 1;
}
crc_table[i]=table_entry;
}
}
/* ===========================================================================
* Write the output window window[0..outcnt-1] and update crc and bytes_out.
* (Used for the decompressed data only.)
*/
static void flush_window(void)
{
int n;
if (outcnt == 0)
return;
for (n = 0; n < outcnt; n++) {
crc = crc_table[((int) crc ^ (window[n])) & 0xff] ^ (crc >> 8);
}
if (fwrite(window, 1, outcnt, out_file) != outcnt) {
error_msg_and_die("Couldnt write");
}
bytes_out += (unsigned long) outcnt;
outcnt = 0;
}
/*
* Free the malloc'ed tables built by huft_build(), which makes a linked
* list of the tables it made, with the links in a dummy first entry of
* each table.
* t: table to free
*/
static int huft_free(huft_t *t)
{
huft_t *p, *q;
/* Go through linked list, freeing from the malloced (t[-1]) address. */
p = t;
while (p != (huft_t *) NULL) {
q = (--p)->v.t;
free((char *) p);
p = q;
}
return 0;
}
typedef unsigned char extra_bits_t;
/* Given a list of code lengths and a maximum table size, make a set of
* tables to decode that set of codes. Return zero on success, one if
* the given code set is incomplete (the tables are still built in this
* case), two if the input is invalid (all zero length codes or an
* oversubscribed set of lengths), and three if not enough memory.
*
* b: code lengths in bits (all assumed <= BMAX)
* n: number of codes (assumed <= N_MAX)
* s: number of simple-valued codes (0..s-1)
* d: list of base values for non-simple codes
* e: list of extra bits for non-simple codes
* t: result: starting table
* m: maximum lookup bits, returns actual
*/
static int huft_build(unsigned int *b, const unsigned int n, const unsigned int s,
const unsigned short *d, const extra_bits_t *e, huft_t **t, int *m)
{
unsigned a; /* counter for codes of length k */
unsigned c[BMAX + 1]; /* bit length count table */
unsigned f; /* i repeats in table every f entries */
int g; /* maximum code length */
int h; /* table level */
register unsigned i; /* counter, current code */
register unsigned j; /* counter */
register int k; /* number of bits in current code */
int l; /* bits per table (returned in m) */
register unsigned *p; /* pointer into c[], b[], or v[] */
register huft_t *q; /* points to current table */
huft_t r; /* table entry for structure assignment */
huft_t *u[BMAX]; /* table stack */
unsigned v[N_MAX]; /* values in order of bit length */
register int w; /* bits before this table == (l * h) */
unsigned x[BMAX + 1]; /* bit offsets, then code stack */
unsigned *xp; /* pointer into x */
int y; /* number of dummy codes added */
unsigned z; /* number of entries in current table */
/* Generate counts for each bit length */
memset ((void *)(c), 0, sizeof(c));
p = b;
i = n;
do {
c[*p]++; /* assume all entries <= BMAX */
p++; /* Can't combine with above line (Solaris bug) */
} while (--i);
if (c[0] == n) { /* null input--all zero length codes */
*t = (huft_t *) NULL;
*m = 0;
return 0;
}
/* Find minimum and maximum length, bound *m by those */
l = *m;
for (j = 1; j <= BMAX; j++)
if (c[j])
break;
k = j; /* minimum code length */
if ((unsigned) l < j)
l = j;
for (i = BMAX; i; i--)
if (c[i])
break;
g = i; /* maximum code length */
if ((unsigned) l > i)
l = i;
*m = l;
/* Adjust last length count to fill out codes, if needed */
for (y = 1 << j; j < i; j++, y <<= 1)
if ((y -= c[j]) < 0)
return 2; /* bad input: more codes than bits */
if ((y -= c[i]) < 0)
return 2;
c[i] += y;
/* Generate starting offsets into the value table for each length */
x[1] = j = 0;
p = c + 1;
xp = x + 2;
while (--i) { /* note that i == g from above */
*xp++ = (j += *p++);
}
/* Make a table of values in order of bit lengths */
p = b;
i = 0;
do {
if ((j = *p++) != 0)
v[x[j]++] = i;
} while (++i < n);
/* Generate the Huffman codes and for each, make the table entries */
x[0] = i = 0; /* first Huffman code is zero */
p = v; /* grab values in bit order */
h = -1; /* no tables yet--level -1 */
w = -l; /* bits decoded == (l * h) */
u[0] = (huft_t *) NULL; /* just to keep compilers happy */
q = (huft_t *) NULL; /* ditto */
z = 0; /* ditto */
/* go through the bit lengths (k already is bits in shortest code) */
for (; k <= g; k++) {
a = c[k];
while (a--) {
/* here i is the Huffman code of length k bits for value *p */
/* make tables up to required level */
while (k > w + l) {
h++;
w += l; /* previous table always l bits */
/* compute minimum size table less than or equal to l bits */
z = (z = g - w) > (unsigned) l ? l : z; /* upper limit on table size */
if ((f = 1 << (j = k - w)) > a + 1) { /* try a k-w bit table *//* too few codes for k-w bit table */
f -= a + 1; /* deduct codes from patterns left */
xp = c + k;
while (++j < z) { /* try smaller tables up to z bits */
if ((f <<= 1) <= *++xp)
break; /* enough codes to use up j bits */
f -= *xp; /* else deduct codes from patterns */
}
}
z = 1 << j; /* table entries for j-bit table */
/* allocate and link in new table */
q = (huft_t *) xmalloc((z + 1) * sizeof(huft_t));
hufts += z + 1; /* track memory usage */
*t = q + 1; /* link to list for huft_free() */
*(t = &(q->v.t)) = NULL;
u[h] = ++q; /* table starts after link */
/* connect to last table, if there is one */
if (h) {
x[h] = i; /* save pattern for backing up */
r.b = (unsigned char) l; /* bits to dump before this table */
r.e = (unsigned char) (16 + j); /* bits in this table */
r.v.t = q; /* pointer to this table */
j = i >> (w - l); /* (get around Turbo C bug) */
u[h - 1][j] = r; /* connect to last table */
}
}
/* set up table entry in r */
r.b = (unsigned char) (k - w);
if (p >= v + n)
r.e = 99; /* out of values--invalid code */
else if (*p < s) {
r.e = (unsigned char) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */
r.v.n = (unsigned short) (*p); /* simple code is just the value */
p++; /* one compiler does not like *p++ */
} else {
r.e = (unsigned char) e[*p - s]; /* non-simple--look up in lists */
r.v.n = d[*p++ - s];
}
/* fill code-like entries with r */
f = 1 << (k - w);
for (j = i >> w; j < z; j += f)
q[j] = r;
/* backwards increment the k-bit code i */
for (j = 1 << (k - 1); i & j; j >>= 1)
i ^= j;
i ^= j;
/* backup over finished tables */
while ((i & ((1 << w) - 1)) != x[h]) {
h--; /* don't need to update q */
w -= l;
}
}
}
/* Return true (1) if we were given an incomplete table */
return y != 0 && g != 1;
}
/*
* inflate (decompress) the codes in a deflated (compressed) block.
* Return an error code or zero if it all goes ok.
*
* tl, td: literal/length and distance decoder tables
* bl, bd: number of bits decoded by tl[] and td[]
*/
static int inflate_codes(huft_t *tl, huft_t *td, int bl, int bd)
{
register unsigned long e; /* table entry flag/number of extra bits */
unsigned long n, d; /* length and index for copy */
unsigned long w; /* current window position */
huft_t *t; /* pointer to table entry */
unsigned ml, md; /* masks for bl and bd bits */
register unsigned long b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local copies of globals */
b = bb; /* initialize bit buffer */
k = bk;
w = outcnt; /* initialize window position */
/* inflate the coded data */
ml = mask_bits[bl]; /* precompute masks for speed */
md = mask_bits[bd];
for (;;) { /* do until end of block */
while (k < (unsigned) bl) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
do {
if (e == 99) {
return 1;
}
b >>= t->b;
k -= t->b;
e -= 16;
while (k < e) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
} while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
b >>= t->b;
k -= t->b;
if (e == 16) { /* then it's a literal */
window[w++] = (unsigned char) t->v.n;
if (w == WSIZE) {
outcnt=(w),
flush_window();
w = 0;
}
} else { /* it's an EOB or a length */
/* exit if end of block */
if (e == 15) {
break;
}
/* get length of block to copy */
while (k < e) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
n = t->v.n + ((unsigned) b & mask_bits[e]);
b >>= e;
k -= e;
/* decode distance of block to copy */
while (k < (unsigned) bd) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
if ((e = (t = td + ((unsigned) b & md))->e) > 16)
do {
if (e == 99)
return 1;
b >>= t->b;
k -= t->b;
e -= 16;
while (k < e) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
} while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
b >>= t->b;
k -= t->b;
while (k < e) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
d = w - t->v.n - ((unsigned) b & mask_bits[e]);
b >>= e;
k -= e;
/* do the copy */
do {
n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n : e);
#if !defined(NOMEMCPY) && !defined(DEBUG)
if (w - d >= e) { /* (this test assumes unsigned comparison) */
memcpy(window + w, window + d, e);
w += e;
d += e;
} else /* do it slow to avoid memcpy() overlap */
#endif /* !NOMEMCPY */
do {
window[w++] = window[d++];
} while (--e);
if (w == WSIZE) {
outcnt=(w),
flush_window();
w = 0;
}
} while (n);
}
}
/* restore the globals from the locals */
outcnt = w; /* restore global window pointer */
bb = b; /* restore global bit buffer */
bk = k;
/* done */
return 0;
}
static const unsigned short cplens[] = { /* Copy lengths for literal codes 257..285 */
3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
};
/* note: see note #13 above about the 258 in this list. */
static const extra_bits_t cplext[] = { /* Extra bits for literal codes 257..285 */
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
}; /* 99==invalid */
static const unsigned short cpdist[] = { /* Copy offsets for distance codes 0..29 */
1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
8193, 12289, 16385, 24577
};
static const extra_bits_t cpdext[] = { /* Extra bits for distance codes */
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
12, 12, 13, 13
};
/* Tables for deflate from PKZIP's appnote.txt. */
static const extra_bits_t border[] = { /* Order of the bit length code lengths */
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
};
/*
* decompress an inflated block
* e: last block flag
*
* GLOBAL VARIABLES: bb, kk,
*/
static int inflate_block(int *e)
{
unsigned t; /* block type */
register unsigned long b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local bit buffer */
b = bb;
k = bk;
/* read in last block bit */
while (k < 1) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
*e = (int) b & 1;
b >>= 1;
k -= 1;
/* read in block type */
while (k < 2) {
b |= ((unsigned long)fgetc(in_file)) << k;
k += 8;
}
t = (unsigned) b & 3;
b >>= 2;
k -= 2;
/* restore the global bit buffer */
bb = b;
bk = k;
/* inflate that block type */
switch (t) {
case 0: /* Inflate stored */
{
unsigned long n; /* number of bytes in block */
unsigned long w; /* current window position */
register unsigned long b_stored; /* bit buffer */
register unsigned long k_stored; /* number of bits in bit buffer */
/* make local copies of globals */
b_stored = bb; /* initialize bit buffer */
k_stored = bk;
w = outcnt; /* initialize window position */
/* go to byte boundary */
n = k_stored & 7;
b_stored >>= n;
k_stored -= n;
/* get the length and its complement */
while (k_stored < 16) {
b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
k_stored += 8;
}
n = ((unsigned) b_stored & 0xffff);
b_stored >>= 16;
k_stored -= 16;
while (k_stored < 16) {
b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
k_stored += 8;
}
if (n != (unsigned) ((~b_stored) & 0xffff)) {
return 1; /* error in compressed data */
}
b_stored >>= 16;
k_stored -= 16;
/* read and output the compressed data */
while (n--) {
while (k_stored < 8) {
b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
k_stored += 8;
}
window[w++] = (unsigned char) b_stored;
if (w == (unsigned long)WSIZE) {
outcnt=(w),
flush_window();
w = 0;
}
b_stored >>= 8;
k_stored -= 8;
}
/* restore the globals from the locals */
outcnt = w; /* restore global window pointer */
bb = b_stored; /* restore global bit buffer */
bk = k_stored;
return 0;
}
case 1: /* Inflate fixed
* decompress an inflated type 1 (fixed Huffman codes) block. We should
* either replace this with a custom decoder, or at least precompute the
* Huffman tables.
*/
{
int i; /* temporary variable */
huft_t *tl; /* literal/length code table */
huft_t *td; /* distance code table */
int bl; /* lookup bits for tl */
int bd; /* lookup bits for td */
unsigned int l[288]; /* length list for huft_build */
/* set up literal table */
for (i = 0; i < 144; i++) {
l[i] = 8;
}
for (; i < 256; i++) {
l[i] = 9;
}
for (; i < 280; i++) {
l[i] = 7;
}
for (; i < 288; i++) { /* make a complete, but wrong code set */
l[i] = 8;
}
bl = 7;
if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
return i;
}
/* set up distance table */
for (i = 0; i < 30; i++) { /* make an incomplete code set */
l[i] = 5;
}
bd = 5;
if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
huft_free(tl);
return i;
}
/* decompress until an end-of-block code */
if (inflate_codes(tl, td, bl, bd))
return 1;
/* free the decoding tables, return */
huft_free(tl);
huft_free(td);
return 0;
}
case 2: /* Inflate dynamic */
{
const int dbits = 6; /* bits in base distance lookup table */
const int lbits = 9; /* bits in base literal/length lookup table */
int i; /* temporary variables */
unsigned j;
unsigned l; /* last length */
unsigned m; /* mask for bit lengths table */
unsigned n; /* number of lengths to get */
huft_t *tl; /* literal/length code table */
huft_t *td; /* distance code table */
int bl; /* lookup bits for tl */
int bd; /* lookup bits for td */
unsigned nb; /* number of bit length codes */
unsigned nl; /* number of literal/length codes */
unsigned nd; /* number of distance codes */
unsigned ll[286 + 30]; /* literal/length and distance code lengths */
register unsigned long b_dynamic; /* bit buffer */
register unsigned k_dynamic; /* number of bits in bit buffer */
/* make local bit buffer */
b_dynamic = bb;
k_dynamic = bk;
/* read in table lengths */
while (k_dynamic < 5) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
nl = 257 + ((unsigned) b_dynamic & 0x1f); /* number of literal/length codes */
b_dynamic >>= 5;
k_dynamic -= 5;
while (k_dynamic < 5) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
nd = 1 + ((unsigned) b_dynamic & 0x1f); /* number of distance codes */
b_dynamic >>= 5;
k_dynamic -= 5;
while (k_dynamic < 4) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
nb = 4 + ((unsigned) b_dynamic & 0xf); /* number of bit length codes */
b_dynamic >>= 4;
k_dynamic -= 4;
if (nl > 286 || nd > 30) {
return 1; /* bad lengths */
}
/* read in bit-length-code lengths */
for (j = 0; j < nb; j++) {
while (k_dynamic < 3) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
ll[border[j]] = (unsigned) b_dynamic & 7;
b_dynamic >>= 3;
k_dynamic -= 3;
}
for (; j < 19; j++) {
ll[border[j]] = 0;
}
/* build decoding table for trees--single level, 7 bit lookup */
bl = 7;
if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
if (i == 1) {
huft_free(tl);
}
return i; /* incomplete code set */
}
/* read in literal and distance code lengths */
n = nl + nd;
m = mask_bits[bl];
i = l = 0;
while ((unsigned) i < n) {
while (k_dynamic < (unsigned) bl) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
j = (td = tl + ((unsigned) b_dynamic & m))->b;
b_dynamic >>= j;
k_dynamic -= j;
j = td->v.n;
if (j < 16) { /* length of code in bits (0..15) */
ll[i++] = l = j; /* save last length in l */
}
else if (j == 16) { /* repeat last length 3 to 6 times */
while (k_dynamic < 2) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
j = 3 + ((unsigned) b_dynamic & 3);
b_dynamic >>= 2;
k_dynamic -= 2;
if ((unsigned) i + j > n) {
return 1;
}
while (j--) {
ll[i++] = l;
}
} else if (j == 17) { /* 3 to 10 zero length codes */
while (k_dynamic < 3) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
j = 3 + ((unsigned) b_dynamic & 7);
b_dynamic >>= 3;
k_dynamic -= 3;
if ((unsigned) i + j > n) {
return 1;
}
while (j--) {
ll[i++] = 0;
}
l = 0;
} else { /* j == 18: 11 to 138 zero length codes */
while (k_dynamic < 7) {
b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
k_dynamic += 8;
}
j = 11 + ((unsigned) b_dynamic & 0x7f);
b_dynamic >>= 7;
k_dynamic -= 7;
if ((unsigned) i + j > n) {
return 1;
}
while (j--) {
ll[i++] = 0;
}
l = 0;
}
}
/* free decoding table for trees */
huft_free(tl);
/* restore the global bit buffer */
bb = b_dynamic;
bk = k_dynamic;
/* build the decoding tables for literal/length and distance codes */
bl = lbits;
if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
if (i == 1) {
error_msg("Incomplete literal tree");
huft_free(tl);
}
return i; /* incomplete code set */
}
bd = dbits;
if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
if (i == 1) {
error_msg("incomplete distance tree");
huft_free(td);
}
huft_free(tl);
return i; /* incomplete code set */
}
/* decompress until an end-of-block code */
if (inflate_codes(tl, td, bl, bd))
return 1;
/* free the decoding tables, return */
huft_free(tl);
huft_free(td);
return 0;
}
default:
/* bad block type */
return 2;
}
}
/*
* decompress an inflated entry
*
* GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
*/
extern int inflate(FILE *in, FILE *out)
{
int e; /* last block flag */
int r; /* result code */
unsigned h = 0; /* maximum struct huft's malloc'ed */
/* initialize window, bit buffer */
outcnt = 0;
bk = 0;
bb = 0;
in_file = in;
out_file = out;
/* Allocate all global buffers (for DYN_ALLOC option) */
window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
bytes_out = 0L;
/* Create the crc table */
make_crc_table();
/* decompress until the last block */
do {
hufts = 0;
if ((r = inflate_block(&e)) != 0) {
return r;
}
if (hufts > h) {
h = hufts;
}
} while (!e);
/* Undo too much lookahead. The next read will be byte aligned so we
* can discard unused bits in the last meaningful byte.
*/
while (bk >= 8) {
bk -= 8;
ungetc((bb << bk), in_file);
}
/* flush out window */
flush_window();
free(window);
free(crc_table);
/* return success */
return 0;
}
/* ===========================================================================
* Unzip in to out. This routine works on gzip files only.
*
* IN assertions: the buffer inbuf contains already the beginning of
* the compressed data, from offsets inptr to insize-1 included.
* The magic header has already been checked. The output buffer is cleared.
* in, out: input and output file descriptors
*/
extern int unzip(FILE *l_in_file, FILE *l_out_file)
{
unsigned char buf[8]; /* extended local header */
unsigned char flags; /* compression flags */
typedef void (*sig_type) (int);
unsigned short i;
if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
(void) signal(SIGINT, (sig_type) abort_gzip);
}
#ifdef SIGTERM
// if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
// (void) signal(SIGTERM, (sig_type) abort_gzip);
// }
#endif
#ifdef SIGHUP
if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
(void) signal(SIGHUP, (sig_type) abort_gzip);
}
#endif
/* Magic header for gzip files, 1F 8B = \037\213 */
if ((fgetc(l_in_file) != 0x1F) || (fgetc(l_in_file) != 0x8b)) {
error_msg("Invalid gzip magic");
return EXIT_FAILURE;
}
/* Check the compression method */
if (fgetc(l_in_file) != 8) {
error_msg("Unknown compression method");
return(-1);
}
flags = (unsigned char) fgetc(l_in_file);
/* Ignore time stamp(4), extra flags(1), OS type(1) */
for (i = 0; i < 6; i++) {
fgetc(l_in_file);
}
if (flags & 0x04) {
/* bit 2 set: extra field present */
const unsigned short extra = fgetc(l_in_file) + (fgetc(l_in_file) << 8);
for (i = 0; i < extra; i++) {
fgetc(l_in_file);
}
}
/* Discard original name if any */
if (flags & 0x08) {
/* bit 3 set: original file name present */
while (fgetc(l_in_file) != 0); /* null */
}
/* Discard file comment if any */
if (flags & 0x10) {
/* bit 4 set: file comment present */
while (fgetc(l_in_file) != 0); /* null */
}
/* Decompress */
if (inflate(l_in_file, l_out_file) != 0) {
error_msg("invalid compressed data--format violated");
}
/* Get the crc and original length
* crc32 (see algorithm.doc)
* uncompressed input size modulo 2^32
*/
fread(buf, 1, 8, l_in_file);
/* Validate decompression - crc */
if ((unsigned int)((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
error_msg("invalid compressed data--crc error");
}
/* Validate decompression - size */
if (((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
error_msg("invalid compressed data--length error");
}
return 0;
}
/*
* This needs access to global variables window and crc_table, so its not in its own file.
*/
extern void gz_close(int gunzip_pid)
{
if (kill(gunzip_pid, SIGTERM) == -1) {
error_msg_and_die("*** Couldnt kill old gunzip process *** aborting");
}
if (waitpid(gunzip_pid, NULL, 0) == -1) {
printf("Couldnt wait ?");
}
free(window);
free(crc_table);
}
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