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hush/gunzip.c
Eric Andersen b610615be9 Updates to a number of apps to remove warnings/compile errors under libc5. 
Tested under both libc5 and libc6 and all seems well with these fixes.
 -Erik
2000-06-19 17:25:40 +00:00

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/* vi: set sw=4 ts=4: */
/*
* Gzip implementation for busybox
*
* Based on GNU gzip 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 <andersen@lineo.com>, <andersee@debian.org>
* to support files as well as stdin/stdout, and to generally behave itself wrt
* command line handling.
*
* 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
*
*/
#include "internal.h"
static const char gunzip_usage[] =
"gunzip [OPTION]... FILE\n"
#ifndef BB_FEATURE_TRIVIAL_HELP
"\nUncompress FILE (or standard input if FILE is '-').\n\n"
"Options:\n"
"\t-c\tWrite output to standard output\n"
"\t-t\tTest compressed file integrity\n"
#endif
;
/* These defines are very important for BusyBox. Without these,
* huge chunks of ram are pre-allocated making the BusyBox bss
* size Freaking Huge(tm), which is a bad thing.*/
#define SMALL_MEM
#define DYN_ALLOC
#define BB_DECLARE_EXTERN
#define bb_need_memory_exhausted
#define bb_need_name_too_long
#include "messages.c"
/* 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
/* Compress files with zip algorithm and 'compress' interface.
* See usage() and help() functions below for all options.
* Outputs:
* file.gz: compressed file with same mode, owner, and utimes
* or stdout with -c option or if stdin used as input.
* If the output file name had to be truncated, the original name is kept
* in the compressed file.
* On MSDOS, file.tmp -> file.tmz. On VMS, file.tmp -> file.tmp-gz.
*
* Using gz on MSDOS would create too many file name conflicts. For
* example, foo.txt -> foo.tgz (.tgz must be reserved as shorthand for
* tar.gz). Similarly, foo.dir and foo.doc would both be mapped to foo.dgz.
* I also considered 12345678.txt -> 12345txt.gz but this truncates the name
* too heavily. There is no ideal solution given the MSDOS 8+3 limitation.
*
* For the meaning of all compilation flags, see comments in Makefile.in.
*/
#include <ctype.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/stat.h>
#include <errno.h>
/* #include "tailor.h" */
/* tailor.h -- target dependent definitions
* Copyright (C) 1992-1993 Jean-loup Gailly.
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
/* The target dependent definitions should be defined here only.
* The target dependent functions should be defined in tailor.c.
*/
#define RECORD_IO 0
#define get_char() get_byte()
#define put_char(c) put_byte(c)
/* I don't like nested includes, but the string and io functions are used
* too often
*/
#include <stdio.h>
#if !defined(NO_STRING_H) || defined(STDC_HEADERS)
# include <string.h>
# if !defined(STDC_HEADERS) && !defined(NO_MEMORY_H) && !defined(__GNUC__)
# include <memory.h>
# endif
# define memzero(s, n) memset ((void *)(s), 0, (n))
#else
# include <strings.h>
# define strchr index
# define strrchr rindex
# define memcpy(d, s, n) bcopy((s), (d), (n))
# define memcmp(s1, s2, n) bcmp((s1), (s2), (n))
# define memzero(s, n) bzero((s), (n))
#endif
#ifndef RETSIGTYPE
# define RETSIGTYPE void
#endif
#define local static
typedef unsigned char uch;
typedef unsigned short ush;
typedef unsigned long ulg;
/* Return codes from gzip */
#define OK 0
#define ERROR 1
#define WARNING 2
/* Compression methods (see algorithm.doc) */
#define DEFLATED 8
extern int method; /* compression method */
/* To save memory for 16 bit systems, some arrays are overlaid between
* the various modules:
* deflate: prev+head window d_buf l_buf outbuf
* unlzw: tab_prefix tab_suffix stack inbuf outbuf
* inflate: window inbuf
* unpack: window inbuf prefix_len
* unlzh: left+right window c_table inbuf c_len
* For compression, input is done in window[]. For decompression, output
* is done in window except for unlzw.
*/
#ifndef INBUFSIZ
# ifdef SMALL_MEM
# define INBUFSIZ 0x2000 /* input buffer size */
# else
# define INBUFSIZ 0x8000 /* input buffer size */
# endif
#endif
#define INBUF_EXTRA 64 /* required by unlzw() */
#ifndef OUTBUFSIZ
# ifdef SMALL_MEM
# define OUTBUFSIZ 8192 /* output buffer size */
# else
# define OUTBUFSIZ 16384 /* output buffer size */
# endif
#endif
#define OUTBUF_EXTRA 2048 /* required by unlzw() */
#define SMALL_MEM
#ifndef DIST_BUFSIZE
# ifdef SMALL_MEM
# define DIST_BUFSIZE 0x2000 /* buffer for distances, see trees.c */
# else
# define DIST_BUFSIZE 0x8000 /* buffer for distances, see trees.c */
# endif
#endif
/*#define DYN_ALLOC*/
#ifdef DYN_ALLOC
# define EXTERN(type, array) extern type * array
# define DECLARE(type, array, size) type * array
# define ALLOC(type, array, size) { \
array = (type*)calloc((size_t)(((size)+1L)/2), 2*sizeof(type)); \
if (array == NULL) errorMsg(memory_exhausted, "gunzip"); \
}
# define FREE(array) {if (array != NULL) free(array), array=NULL;}
#else
# define EXTERN(type, array) extern type array[]
# define DECLARE(type, array, size) type array[size]
# define ALLOC(type, array, size)
# define FREE(array)
#endif
EXTERN(uch, inbuf); /* input buffer */
EXTERN(uch, outbuf); /* output buffer */
EXTERN(ush, d_buf); /* buffer for distances, see trees.c */
EXTERN(uch, window); /* Sliding window and suffix table (unlzw) */
#define tab_suffix window
#ifndef MAXSEG_64K
# define tab_prefix prev /* hash link (see deflate.c) */
# define head (prev+WSIZE) /* hash head (see deflate.c) */
EXTERN(ush, tab_prefix); /* prefix code (see unlzw.c) */
#else
# define tab_prefix0 prev
# define head tab_prefix1
EXTERN(ush, tab_prefix0); /* prefix for even codes */
EXTERN(ush, tab_prefix1); /* prefix for odd codes */
#endif
extern unsigned insize; /* valid bytes in inbuf */
extern unsigned inptr; /* index of next byte to be processed in inbuf */
extern unsigned outcnt; /* bytes in output buffer */
extern long bytes_in; /* number of input bytes */
extern long bytes_out; /* number of output bytes */
extern long header_bytes; /* number of bytes in gzip header */
extern long ifile_size; /* input file size, -1 for devices (debug only) */
typedef int file_t; /* Do not use stdio */
#define NO_FILE (-1) /* in memory compression */
#define GZIP_MAGIC "\037\213" /* Magic header for gzip files, 1F 8B */
/* gzip flag byte */
#define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */
#define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define COMMENT 0x10 /* bit 4 set: file comment present */
#define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */
#define RESERVED 0xC0 /* bit 6,7: reserved */
#ifndef WSIZE
# define WSIZE 0x8000 /* window size--must be a power of two, and */
#endif /* at least 32K for zip's deflate method */
#define MIN_MATCH 3
#define MAX_MATCH 258
/* The minimum and maximum match lengths */
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
* See deflate.c for comments about the MIN_MATCH+1.
*/
#define MAX_DIST (WSIZE-MIN_LOOKAHEAD)
/* In order to simplify the code, particularly on 16 bit machines, match
* distances are limited to MAX_DIST instead of WSIZE.
*/
extern int exit_code; /* program exit code */
extern int verbose; /* be verbose (-v) */
extern int level; /* compression level */
extern int test; /* check .z file integrity */
extern int save_orig_name; /* set if original name must be saved */
#define get_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(0))
#define try_byte() (inptr < insize ? inbuf[inptr++] : fill_inbuf(1))
/* put_byte is used for the compressed output, put_ubyte for the
* uncompressed output. However unlzw() uses window for its
* suffix table instead of its output buffer, so it does not use put_ubyte
* (to be cleaned up).
*/
#define put_byte(c) {outbuf[outcnt++]=(uch)(c); if (outcnt==OUTBUFSIZ)\
flush_outbuf();}
#define put_ubyte(c) {window[outcnt++]=(uch)(c); if (outcnt==WSIZE)\
flush_window();}
/* Output a 16 bit value, lsb first */
#define put_short(w) \
{ if (outcnt < OUTBUFSIZ-2) { \
outbuf[outcnt++] = (uch) ((w) & 0xff); \
outbuf[outcnt++] = (uch) ((ush)(w) >> 8); \
} else { \
put_byte((uch)((w) & 0xff)); \
put_byte((uch)((ush)(w) >> 8)); \
} \
}
/* Output a 32 bit value to the bit stream, lsb first */
#define put_long(n) { \
put_short((n) & 0xffff); \
put_short(((ulg)(n)) >> 16); \
}
#define seekable() 0 /* force sequential output */
#define translate_eol 0 /* no option -a yet */
#define tolow(c) (isupper(c) ? (c)-'A'+'a' : (c)) /* force to lower case */
/* Macros for getting two-byte and four-byte header values */
#define SH(p) ((ush)(uch)((p)[0]) | ((ush)(uch)((p)[1]) << 8))
#define LG(p) ((ulg)(SH(p)) | ((ulg)(SH((p)+2)) << 16))
/* Diagnostic functions */
#ifdef DEBUG
# define Assert(cond,msg) {if(!(cond)) errorMsg(msg);}
# define Trace(x) fprintf x
# define Tracev(x) {if (verbose) fprintf x ;}
# define Tracevv(x) {if (verbose>1) fprintf x ;}
# define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
#else
# define Assert(cond,msg)
# define Trace(x)
# define Tracev(x)
# define Tracevv(x)
# define Tracec(c,x)
# define Tracecv(c,x)
#endif
#define WARN(msg) {fprintf msg ; \
if (exit_code == OK) exit_code = WARNING;}
/* in unzip.c */
extern int unzip (int in, int out);
/* in gzip.c */
RETSIGTYPE abort_gzip (void);
/* in deflate.c */
void lm_init (int pack_level, ush * flags);
ulg deflate (void);
/* in trees.c */
void ct_init (ush * attr, int *method);
int ct_tally (int dist, int lc);
ulg flush_block (char *buf, ulg stored_len, int eof);
/* in bits.c */
void bi_init (file_t zipfile);
void send_bits (int value, int length);
unsigned bi_reverse (unsigned value, int length);
void bi_windup (void);
void copy_block (char *buf, unsigned len, int header);
/* in util.c: */
extern ulg updcrc (uch * s, unsigned n);
extern void clear_bufs (void);
static int fill_inbuf (int eof_ok);
extern void flush_outbuf (void);
static void flush_window (void);
extern void write_buf (int fd, void * buf, unsigned cnt);
#ifndef __linux__
static char *basename (char *fname);
#endif /* not __linux__ */
void read_error_msg (void);
void write_error_msg (void);
/* in inflate.c */
static int inflate (void);
/* #include "lzw.h" */
/* lzw.h -- define the lzw functions.
* Copyright (C) 1992-1993 Jean-loup Gailly.
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
#if !defined(OF) && defined(lint)
# include "gzip.h"
#endif
#ifndef BITS
# define BITS 16
#endif
#define INIT_BITS 9 /* Initial number of bits per code */
#define LZW_MAGIC "\037\235" /* Magic header for lzw files, 1F 9D */
#define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
/* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
* It's a pity that old uncompress does not check bit 0x20. That makes
* extension of the format actually undesirable because old compress
* would just crash on the new format instead of giving a meaningful
* error message. It does check the number of bits, but it's more
* helpful to say "unsupported format, get a new version" than
* "can only handle 16 bits".
*/
#define BLOCK_MODE 0x80
/* Block compression: if table is full and compression rate is dropping,
* clear the dictionary.
*/
#define LZW_RESERVED 0x60 /* reserved bits */
#define CLEAR 256 /* flush the dictionary */
#define FIRST (CLEAR+1) /* first free entry */
extern int maxbits; /* max bits per code for LZW */
extern int block_mode; /* block compress mode -C compatible with 2.0 */
extern int lzw (int in, int out);
extern int unlzw (int in, int out);
/* #include "revision.h" */
/* revision.h -- define the version number
* Copyright (C) 1992-1993 Jean-loup Gailly.
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
#define VERSION "1.2.4"
#define PATCHLEVEL 0
#define REVDATE "18 Aug 93"
/* This version does not support compression into old compress format: */
#ifdef LZW
# undef LZW
#endif
#include <time.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#if defined(DIRENT)
# include <dirent.h>
typedef struct dirent dir_type;
# define NLENGTH(dirent) ((int)strlen((dirent)->d_name))
# define DIR_OPT "DIRENT"
#else
# define NLENGTH(dirent) ((dirent)->d_namlen)
# ifdef SYSDIR
# include <sys/dir.h>
typedef struct direct dir_type;
# define DIR_OPT "SYSDIR"
# else
# ifdef SYSNDIR
# include <sys/ndir.h>
typedef struct direct dir_type;
# define DIR_OPT "SYSNDIR"
# else
# ifdef NDIR
# include <ndir.h>
typedef struct direct dir_type;
# define DIR_OPT "NDIR"
# else
# define NO_DIR
# define DIR_OPT "NO_DIR"
# endif
# endif
# endif
#endif
#if !defined(S_ISDIR) && defined(S_IFDIR)
# define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif
#if !defined(S_ISREG) && defined(S_IFREG)
# define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#endif
typedef RETSIGTYPE(*sig_type) (int);
#ifndef O_BINARY
# define O_BINARY 0 /* creation mode for open() */
#endif
#ifndef O_CREAT
/* Pure BSD system? */
# include <sys/file.h>
# ifndef O_CREAT
# define O_CREAT FCREAT
# endif
# ifndef O_EXCL
# define O_EXCL FEXCL
# endif
#endif
#ifndef S_IRUSR
# define S_IRUSR 0400
#endif
#ifndef S_IWUSR
# define S_IWUSR 0200
#endif
#define RW_USER (S_IRUSR | S_IWUSR) /* creation mode for open() */
#ifndef MAX_PATH_LEN /* max pathname length */
# ifdef BUFSIZ
# define MAX_PATH_LEN BUFSIZ
# else
# define MAX_PATH_LEN 1024
# endif
#endif
#ifndef SEEK_END
# define SEEK_END 2
#endif
#ifdef NO_OFF_T
typedef long off_t;
off_t lseek (int fd, off_t offset, int whence);
#endif
/* global buffers */
DECLARE(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
DECLARE(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
DECLARE(ush, d_buf, DIST_BUFSIZE);
DECLARE(uch, window, 2L * WSIZE);
#ifndef MAXSEG_64K
DECLARE(ush, tab_prefix, 1L << BITS);
#else
DECLARE(ush, tab_prefix0, 1L << (BITS - 1));
DECLARE(ush, tab_prefix1, 1L << (BITS - 1));
#endif
/* local variables */
int test_mode = 0; /* check file integrity option */
int foreground; /* set if program run in foreground */
int maxbits = BITS; /* max bits per code for LZW */
int method = DEFLATED; /* compression method */
int exit_code = OK; /* program exit code */
int last_member; /* set for .zip and .Z files */
int part_nb; /* number of parts in .gz file */
long ifile_size; /* input file size, -1 for devices (debug only) */
long bytes_in; /* number of input bytes */
long bytes_out; /* number of output bytes */
long total_in = 0; /* input bytes for all files */
long total_out = 0; /* output bytes for all files */
struct stat istat; /* status for input file */
int ifd; /* input file descriptor */
int ofd; /* output file descriptor */
unsigned insize; /* valid bytes in inbuf */
unsigned inptr; /* index of next byte to be processed in inbuf */
unsigned outcnt; /* bytes in output buffer */
long header_bytes; /* number of bytes in gzip header */
/* local functions */
local int get_method (int in);
#define strequ(s1, s2) (strcmp((s1),(s2)) == 0)
/* ======================================================================== */
int gunzip_main(int argc, char **argv)
{
int file_count; /* number of files to precess */
int to_stdout = 0;
int fromstdin = 0;
int result;
int inFileNum;
int outFileNum;
int delInputFile = 0;
struct stat statBuf;
char *delFileName;
char ifname[MAX_PATH_LEN + 1]; /* input file name */
char ofname[MAX_PATH_LEN + 1]; /* output file name */
if (strcmp(*argv, "zcat") == 0) {
to_stdout = 1;
if (argc == 1) {
fromstdin = 1;
}
}
/* Parse any options */
while (--argc > 0 && **(++argv) == '-') {
if (*((*argv) + 1) == '\0') {
fromstdin = 1;
to_stdout = 1;
}
while (*(++(*argv))) {
switch (**argv) {
case 'c':
to_stdout = 1;
break;
case 't':
test_mode = 1;
break;
default:
usage(gunzip_usage);
}
}
}
foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
if (foreground) {
(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
file_count = argc - optind;
/* Allocate all global buffers (for DYN_ALLOC option) */
ALLOC(uch, inbuf, INBUFSIZ + INBUF_EXTRA);
ALLOC(uch, outbuf, OUTBUFSIZ + OUTBUF_EXTRA);
ALLOC(ush, d_buf, DIST_BUFSIZE);
ALLOC(uch, window, 2L * WSIZE);
#ifndef MAXSEG_64K
ALLOC(ush, tab_prefix, 1L << BITS);
#else
ALLOC(ush, tab_prefix0, 1L << (BITS - 1));
ALLOC(ush, tab_prefix1, 1L << (BITS - 1));
#endif
if (fromstdin == 1) {
strcpy(ofname, "stdin");
inFileNum = fileno(stdin);
ifile_size = -1L; /* convention for unknown size */
} else {
/* Open up the input file */
if (*argv == '\0')
usage(gunzip_usage);
if (strlen(*argv) > MAX_PATH_LEN) {
fprintf(stderr, name_too_long, "gunzip");
exit(WARNING);
}
strcpy(ifname, *argv);
/* Open input fille */
inFileNum = open(ifname, O_RDONLY);
if (inFileNum < 0) {
perror(ifname);
exit(WARNING);
}
/* Get the time stamp on the input file. */
result = stat(ifname, &statBuf);
if (result < 0) {
perror(ifname);
exit(WARNING);
}
ifile_size = statBuf.st_size;
}
if (to_stdout == 1) {
/* And get to work */
strcpy(ofname, "stdout");
outFileNum = fileno(stdout);
clear_bufs(); /* clear input and output buffers */
part_nb = 0;
/* Actually do the compression/decompression. */
unzip(inFileNum, outFileNum);
} else if (test_mode) {
/* Actually do the compression/decompression. */
unzip(inFileNum, 2);
} else {
char *pos;
/* And get to work */
if (strlen(ifname) > MAX_PATH_LEN - 4) {
fprintf(stderr, name_too_long, "gunzip");
exit(WARNING);
}
strcpy(ofname, ifname);
pos = strstr(ofname, ".gz");
if (pos != NULL) {
*pos = '\0';
delInputFile = 1;
} else {
pos = strstr(ofname, ".tgz");
if (pos != NULL) {
*pos = '\0';
strcat(pos, ".tar");
delInputFile = 1;
}
}
/* Open output fille */
#if (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW);
#else
outFileNum = open(ofname, O_RDWR | O_CREAT | O_EXCL);
#endif
if (outFileNum < 0) {
perror(ofname);
exit(WARNING);
}
/* Set permissions on the file */
fchmod(outFileNum, statBuf.st_mode);
clear_bufs(); /* clear input and output buffers */
part_nb = 0;
/* Actually do the compression/decompression. */
result = unzip(inFileNum, outFileNum);
close(outFileNum);
close(inFileNum);
/* Delete the original file */
if (result == OK)
delFileName = ifname;
else
delFileName = ofname;
if (delInputFile == 1 && unlink(delFileName) < 0) {
perror(delFileName);
exit(FALSE);
}
}
return(exit_code);
}
/* ========================================================================
* Check the magic number of the input file and update ofname if an
* original name was given and to_stdout is not set.
* Return the compression method, -1 for error, -2 for warning.
* Set inptr to the offset of the next byte to be processed.
* Updates time_stamp if there is one and --no-time is not used.
* This function may be called repeatedly for an input file consisting
* of several contiguous gzip'ed members.
* IN assertions: there is at least one remaining compressed member.
* If the member is a zip file, it must be the only one.
*/
local int get_method(in)
int in; /* input file descriptor */
{
uch flags; /* compression flags */
char magic[2]; /* magic header */
magic[0] = (char) get_byte();
magic[1] = (char) get_byte();
method = -1; /* unknown yet */
part_nb++; /* number of parts in gzip file */
header_bytes = 0;
last_member = RECORD_IO;
/* assume multiple members in gzip file except for record oriented I/O */
if (memcmp(magic, GZIP_MAGIC, 2) == 0) {
method = (int) get_byte();
if (method != DEFLATED) {
fprintf(stderr,
"unknown method %d -- get newer version of gzip\n",
method);
exit_code = ERROR;
return -1;
}
flags = (uch) get_byte();
(ulg) get_byte(); /* Ignore time stamp */
(ulg) get_byte();
(ulg) get_byte();
(ulg) get_byte();
(void) get_byte(); /* Ignore extra flags for the moment */
(void) get_byte(); /* Ignore OS type for the moment */
if ((flags & EXTRA_FIELD) != 0) {
unsigned len = (unsigned) get_byte();
len |= ((unsigned) get_byte()) << 8;
while (len--)
(void) get_byte();
}
/* Discard original name if any */
if ((flags & ORIG_NAME) != 0) {
while (get_char() != 0) /* null */
;
}
/* Discard file comment if any */
if ((flags & COMMENT) != 0) {
while (get_char() != 0) /* null */
;
}
if (part_nb == 1) {
header_bytes = inptr + 2 * sizeof(long); /* include crc and size */
}
}
if (method >= 0)
return method;
if (part_nb == 1) {
fprintf(stderr, "\nnot in gzip format\n");
exit_code = ERROR;
return -1;
} else {
WARN((stderr, "\ndecompression OK, trailing garbage ignored\n"));
return -2;
}
}
/* ========================================================================
* Signal and error handler.
*/
RETSIGTYPE abort_gzip()
{
exit(ERROR);
}
/* unzip.c -- decompress files in gzip or pkzip format.
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*
* The code in this file is derived from the file funzip.c written
* and put in the public domain by Mark Adler.
*/
/*
This version can extract files in gzip or pkzip format.
For the latter, only the first entry is extracted, and it has to be
either deflated or stored.
*/
/* #include "crypt.h" */
/* crypt.h (dummy version) -- do not perform encryption
* Hardly worth copyrighting :-)
*/
#ifdef CRYPT
# undef CRYPT /* dummy version */
#endif
#define RAND_HEAD_LEN 12 /* length of encryption random header */
#define zencode
#define zdecode
/* PKZIP header definitions */
#define LOCSIG 0x04034b50L /* four-byte lead-in (lsb first) */
#define LOCFLG 6 /* offset of bit flag */
#define CRPFLG 1 /* bit for encrypted entry */
#define EXTFLG 8 /* bit for extended local header */
#define LOCHOW 8 /* offset of compression method */
#define LOCTIM 10 /* file mod time (for decryption) */
#define LOCCRC 14 /* offset of crc */
#define LOCSIZ 18 /* offset of compressed size */
#define LOCLEN 22 /* offset of uncompressed length */
#define LOCFIL 26 /* offset of file name field length */
#define LOCEXT 28 /* offset of extra field length */
#define LOCHDR 30 /* size of local header, including sig */
#define EXTHDR 16 /* size of extended local header, inc sig */
/* Globals */
char *key; /* not used--needed to link crypt.c */
int pkzip = 0; /* set for a pkzip file */
int ext_header = 0; /* set if extended local header */
/* ===========================================================================
* Unzip in to out. This routine works on both gzip and pkzip files.
*
* 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.
*/
int unzip(in, out)
int in, out; /* input and output file descriptors */
{
ulg orig_crc = 0; /* original crc */
ulg orig_len = 0; /* original uncompressed length */
int n;
uch buf[EXTHDR]; /* extended local header */
ifd = in;
ofd = out;
method = get_method(ifd);
if (method < 0) {
exit(exit_code); /* error message already emitted */
}
updcrc(NULL, 0); /* initialize crc */
if (pkzip && !ext_header) { /* crc and length at the end otherwise */
orig_crc = LG(inbuf + LOCCRC);
orig_len = LG(inbuf + LOCLEN);
}
/* Decompress */
if (method == DEFLATED) {
int res = inflate();
if (res == 3) {
errorMsg(memory_exhausted, "gunzip");
} else if (res != 0) {
errorMsg("invalid compressed data--format violated");
}
} else {
errorMsg("internal error, invalid method");
}
/* Get the crc and original length */
if (!pkzip) {
/* crc32 (see algorithm.doc)
* uncompressed input size modulo 2^32
*/
for (n = 0; n < 8; n++) {
buf[n] = (uch) get_byte(); /* may cause an error if EOF */
}
orig_crc = LG(buf);
orig_len = LG(buf + 4);
} else if (ext_header) { /* If extended header, check it */
/* signature - 4bytes: 0x50 0x4b 0x07 0x08
* CRC-32 value
* compressed size 4-bytes
* uncompressed size 4-bytes
*/
for (n = 0; n < EXTHDR; n++) {
buf[n] = (uch) get_byte(); /* may cause an error if EOF */
}
orig_crc = LG(buf + 4);
orig_len = LG(buf + 12);
}
/* Validate decompression */
if (orig_crc != updcrc(outbuf, 0)) {
errorMsg("invalid compressed data--crc error");
}
if (orig_len != (ulg) bytes_out) {
errorMsg("invalid compressed data--length error");
}
/* Check if there are more entries in a pkzip file */
if (pkzip && inptr + 4 < insize && LG(inbuf + inptr) == LOCSIG) {
WARN((stderr, "has more than one entry--rest ignored\n"));
}
ext_header = pkzip = 0; /* for next file */
return OK;
}
/* util.c -- utility functions for gzip support
* Copyright (C) 1992-1993 Jean-loup Gailly
* This is free software; you can redistribute it and/or modify it under the
* terms of the GNU General Public License, see the file COPYING.
*/
#include <ctype.h>
#include <errno.h>
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifndef NO_FCNTL_H
# include <fcntl.h>
#endif
#if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
# include <stdlib.h>
#else
extern int errno;
#endif
static const ulg crc_32_tab[]; /* crc table, defined below */
/* ===========================================================================
* Run a set of bytes through the crc shift register. If s is a NULL
* pointer, then initialize the crc shift register contents instead.
* Return the current crc in either case.
*/
ulg updcrc(s, n)
uch *s; /* pointer to bytes to pump through */
unsigned n; /* number of bytes in s[] */
{
register ulg c; /* temporary variable */
static ulg crc = (ulg) 0xffffffffL; /* shift register contents */
if (s == NULL) {
c = 0xffffffffL;
} else {
c = crc;
if (n)
do {
c = crc_32_tab[((int) c ^ (*s++)) & 0xff] ^ (c >> 8);
} while (--n);
}
crc = c;
return c ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
}
/* ===========================================================================
* Clear input and output buffers
*/
void clear_bufs(void)
{
outcnt = 0;
insize = inptr = 0;
bytes_in = bytes_out = 0L;
}
/* ===========================================================================
* Fill the input buffer. This is called only when the buffer is empty.
*/
int fill_inbuf(eof_ok)
int eof_ok; /* set if EOF acceptable as a result */
{
int len;
/* Read as much as possible */
insize = 0;
errno = 0;
do {
len = read(ifd, (char *) inbuf + insize, INBUFSIZ - insize);
if (len == 0 || len == EOF)
break;
insize += len;
} while (insize < INBUFSIZ);
if (insize == 0) {
if (eof_ok)
return EOF;
read_error_msg();
}
bytes_in += (ulg) insize;
inptr = 1;
return inbuf[0];
}
/* ===========================================================================
* Write the output buffer outbuf[0..outcnt-1] and update bytes_out.
* (used for the compressed data only)
*/
void flush_outbuf()
{
if (outcnt == 0)
return;
if (!test_mode)
write_buf(ofd, (char *) outbuf, outcnt);
bytes_out += (ulg) outcnt;
outcnt = 0;
}
/* ===========================================================================
* Write the output window window[0..outcnt-1] and update crc and bytes_out.
* (Used for the decompressed data only.)
*/
void flush_window()
{
if (outcnt == 0)
return;
updcrc(window, outcnt);
if (!test_mode)
write_buf(ofd, (char *) window, outcnt);
bytes_out += (ulg) outcnt;
outcnt = 0;
}
/* ===========================================================================
* Does the same as write(), but also handles partial pipe writes and checks
* for error return.
*/
void write_buf(fd, buf, cnt)
int fd;
void * buf;
unsigned cnt;
{
unsigned n;
while ((n = write(fd, buf, cnt)) != cnt) {
if (n == (unsigned) (-1)) {
write_error_msg();
}
cnt -= n;
buf = (void *) ((char *) buf + n);
}
}
#if defined(NO_STRING_H) && !defined(STDC_HEADERS)
/* Provide missing strspn and strcspn functions. */
# ifndef __STDC__
# define const
# endif
int strspn (const char *s, const char *accept);
int strcspn (const char *s, const char *reject);
/* ========================================================================
* Return the length of the maximum initial segment
* of s which contains only characters in accept.
*/
int strspn(s, accept)
const char *s;
const char *accept;
{
register const char *p;
register const char *a;
register int count = 0;
for (p = s; *p != '\0'; ++p) {
for (a = accept; *a != '\0'; ++a) {
if (*p == *a)
break;
}
if (*a == '\0')
return count;
++count;
}
return count;
}
/* ========================================================================
* Return the length of the maximum inital segment of s
* which contains no characters from reject.
*/
int strcspn(s, reject)
const char *s;
const char *reject;
{
register int count = 0;
while (*s != '\0') {
if (strchr(reject, *s++) != NULL)
return count;
++count;
}
return count;
}
#endif /* NO_STRING_H */
/* ========================================================================
* Error handlers.
*/
void read_error_msg()
{
fprintf(stderr, "\n");
if (errno != 0) {
perror("");
} else {
fprintf(stderr, "unexpected end of file\n");
}
abort_gzip();
}
void write_error_msg()
{
fprintf(stderr, "\n");
perror("");
abort_gzip();
}
/* ========================================================================
* Table of CRC-32's of all single-byte values (made by makecrc.c)
*/
static const ulg crc_32_tab[] = {
0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
0x2d02ef8dL
};
/* inflate.c -- Not copyrighted 1992 by Mark Adler
version c10p1, 10 January 1993 */
/* You can do whatever you like with this source file, though I would
prefer that if you modify it and redistribute it that you include
comments to that effect with your name and the date. Thank you.
[The history has been moved to the file ChangeLog.]
*/
/*
Inflate deflated (PKZIP's method 8 compressed) data. The compression
method searches for as much of the current string of bytes (up to a
length of 258) in the previous 32K bytes. If it doesn't find any
matches (of at least length 3), it codes the next byte. Otherwise, it
codes the length of the matched string and its distance backwards from
the current position. There is a single Huffman code that codes both
single bytes (called "literals") and match lengths. A second Huffman
code codes the distance information, which follows a length code. Each
length or distance code actually represents a base value and a number
of "extra" (sometimes zero) bits to get to add to the base value. At
the end of each deflated block is a special end-of-block (EOB) literal/
length code. The decoding process is basically: get a literal/length
code; if EOB then done; if a literal, emit the decoded byte; if a
length then get the distance and emit the referred-to bytes from the
sliding window of previously emitted data.
There are (currently) three kinds of inflate blocks: stored, fixed, and
dynamic. The compressor deals with some chunk of data at a time, and
decides which method to use on a chunk-by-chunk basis. A chunk might
typically be 32K or 64K. If the chunk is uncompressible, then the
"stored" method is used. In this case, the bytes are simply stored as
is, eight bits per byte, with none of the above coding. The bytes are
preceded by a count, since there is no longer an EOB code.
If the data is compressible, then either the fixed or dynamic methods
are used. In the dynamic method, the compressed data is preceded by
an encoding of the literal/length and distance Huffman codes that are
to be used to decode this block. The representation is itself Huffman
coded, and so is preceded by a description of that code. These code
descriptions take up a little space, and so for small blocks, there is
a predefined set of codes, called the fixed codes. The fixed method is
used if the block codes up smaller that way (usually for quite small
chunks), otherwise the dynamic method is used. In the latter case, the
codes are customized to the probabilities in the current block, and so
can code it much better than the pre-determined fixed codes.
The Huffman codes themselves are decoded using a mutli-level table
lookup, in order to maximize the speed of decoding plus the speed of
building the decoding tables. See the comments below that precede the
lbits and dbits tuning parameters.
*/
/*
Notes beyond the 1.93a appnote.txt:
1. Distance pointers never point before the beginning of the output
stream.
2. Distance pointers can point back across blocks, up to 32k away.
3. There is an implied maximum of 7 bits for the bit length table and
15 bits for the actual data.
4. If only one code exists, then it is encoded using one bit. (Zero
would be more efficient, but perhaps a little confusing.) If two
codes exist, they are coded using one bit each (0 and 1).
5. There is no way of sending zero distance codes--a dummy must be
sent if there are none. (History: a pre 2.0 version of PKZIP would
store blocks with no distance codes, but this was discovered to be
too harsh a criterion.) Valid only for 1.93a. 2.04c does allow
zero distance codes, which is sent as one code of zero bits in
length.
6. There are up to 286 literal/length codes. Code 256 represents the
end-of-block. Note however that the static length tree defines
288 codes just to fill out the Huffman codes. Codes 286 and 287
cannot be used though, since there is no length base or extra bits
defined for them. Similarly, there are up to 30 distance codes.
However, static trees define 32 codes (all 5 bits) to fill out the
Huffman codes, but the last two had better not show up in the data.
7. Unzip can check dynamic Huffman blocks for complete code sets.
The exception is that a single code would not be complete (see #4).
8. The five bits following the block type is really the number of
literal codes sent minus 257.
9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
(1+6+6). Therefore, to output three times the length, you output
three codes (1+1+1), whereas to output four times the same length,
you only need two codes (1+3). Hmm.
10. In the tree reconstruction algorithm, Code = Code + Increment
only if BitLength(i) is not zero. (Pretty obvious.)
11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19)
12. Note: length code 284 can represent 227-258, but length code 285
really is 258. The last length deserves its own, short code
since it gets used a lot in very redundant files. The length
258 is special since 258 - 3 (the min match length) is 255.
13. The literal/length and distance code bit lengths are read as a
single stream of lengths. It is possible (and advantageous) for
a repeat code (16, 17, or 18) to go across the boundary between
the two sets of lengths.
*/
#include <sys/types.h>
#if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
# include <stdlib.h>
#endif
#define slide window
/* Huffman code lookup table entry--this entry is four bytes for machines
that have 16-bit pointers (e.g. PC's in the small or medium model).
Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16
means that v is a literal, 16 < e < 32 means that v is a pointer to
the next table, which codes e - 16 bits, and lastly e == 99 indicates
an unused code. If a code with e == 99 is looked up, this implies an
error in the data. */
struct huft {
uch e; /* number of extra bits or operation */
uch b; /* number of bits in this code or subcode */
union {
ush n; /* literal, length base, or distance base */
struct huft *t; /* pointer to next level of table */
} v;
};
/* Function prototypes */
int huft_build (unsigned *, unsigned, unsigned, ush *, ush *,
struct huft **, int *);
int huft_free (struct huft *);
int inflate_codes (struct huft *, struct huft *, int, int);
int inflate_stored (void);
int inflate_fixed (void);
int inflate_dynamic (void);
int inflate_block (int *);
int inflate (void);
/* The inflate algorithm uses a sliding 32K byte window on the uncompressed
stream to find repeated byte strings. This is implemented here as a
circular buffer. The index is updated simply by incrementing and then
and'ing with 0x7fff (32K-1). */
/* It is left to other modules to supply the 32K area. It is assumed
to be usable as if it were declared "uch slide[32768];" or as just
"uch *slide;" and then malloc'ed in the latter case. The definition
must be in unzip.h, included above. */
/* unsigned wp; current position in slide */
#define wp outcnt
#define flush_output(w) (wp=(w),flush_window())
/* Tables for deflate from PKZIP's appnote.txt. */
static unsigned 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
};
static ush 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 ush 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 ush 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 ush 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
};
/* Macros for inflate() bit peeking and grabbing.
The usage is:
NEEDBITS(j)
x = b & mask_bits[j];
DUMPBITS(j)
where NEEDBITS makes sure that b has at least j bits in it, and
DUMPBITS removes the bits from b. The macros use the variable k
for the number of bits in b. Normally, b and k are register
variables for speed, and are initialized at the beginning of a
routine that uses these macros from a global bit buffer and count.
If we assume that EOB will be the longest code, then we will never
ask for bits with NEEDBITS that are beyond the end of the stream.
So, NEEDBITS should not read any more bytes than are needed to
meet the request. Then no bytes need to be "returned" to the buffer
at the end of the last block.
However, this assumption is not true for fixed blocks--the EOB code
is 7 bits, but the other literal/length codes can be 8 or 9 bits.
(The EOB code is shorter than other codes because fixed blocks are
generally short. So, while a block always has an EOB, many other
literal/length codes have a significantly lower probability of
showing up at all.) However, by making the first table have a
lookup of seven bits, the EOB code will be found in that first
lookup, and so will not require that too many bits be pulled from
the stream.
*/
ulg bb; /* bit buffer */
unsigned bk; /* bits in bit buffer */
ush mask_bits[] = {
0x0000,
0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};
#ifdef CRYPT
uch cc;
# define NEXTBYTE() (cc = get_byte(), zdecode(cc), cc)
#else
# define NEXTBYTE() (uch)get_byte()
#endif
#define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}}
#define DUMPBITS(n) {b>>=(n);k-=(n);}
/*
Huffman code decoding is performed using a multi-level table lookup.
The fastest way to decode is to simply build a lookup table whose
size is determined by the longest code. However, the time it takes
to build this table can also be a factor if the data being decoded
is not very long. The most common codes are necessarily the
shortest codes, so those codes dominate the decoding time, and hence
the speed. The idea is you can have a shorter table that decodes the
shorter, more probable codes, and then point to subsidiary tables for
the longer codes. The time it costs to decode the longer codes is
then traded against the time it takes to make longer tables.
This results of this trade are in the variables lbits and dbits
below. lbits is the number of bits the first level table for literal/
length codes can decode in one step, and dbits is the same thing for
the distance codes. Subsequent tables are also less than or equal to
those sizes. These values may be adjusted either when all of the
codes are shorter than that, in which case the longest code length in
bits is used, or when the shortest code is *longer* than the requested
table size, in which case the length of the shortest code in bits is
used.
There are two different values for the two tables, since they code a
different number of possibilities each. The literal/length table
codes 286 possible values, or in a flat code, a little over eight
bits. The distance table codes 30 possible values, or a little less
than five bits, flat. The optimum values for speed end up being
about one bit more than those, so lbits is 8+1 and dbits is 5+1.
The optimum values may differ though from machine to machine, and
possibly even between compilers. Your mileage may vary.
*/
int lbits = 9; /* bits in base literal/length lookup table */
int dbits = 6; /* bits in base distance lookup table */
/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
#define BMAX 16 /* maximum bit length of any code (16 for explode) */
#define N_MAX 288 /* maximum number of codes in any set */
unsigned hufts; /* track memory usage */
int huft_build(b, n, s, d, e, t, m)
unsigned *b; /* code lengths in bits (all assumed <= BMAX) */
unsigned n; /* number of codes (assumed <= N_MAX) */
unsigned s; /* number of simple-valued codes (0..s-1) */
ush *d; /* list of base values for non-simple codes */
ush *e; /* list of extra bits for non-simple codes */
struct huft **t; /* result: starting table */
int *m; /* maximum lookup bits, returns actual */
/* 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. */
{
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 struct huft *q; /* points to current table */
struct huft r; /* table entry for structure assignment */
struct huft *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 */
memzero(c, sizeof(c));
p = b;
i = n;
do {
Tracecv(*p,
(stderr,
(n - i >= ' '
&& n - i <= '~' ? "%c %d\n" : "0x%x %d\n"), n - i, *p));
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 = (struct huft *) 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] = (struct huft *) NULL; /* just to keep compilers happy */
q = (struct huft *) 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 */
if (
(q =
(struct huft *) malloc((z + 1) *
sizeof(struct huft))) ==
(struct huft *) NULL) {
if (h)
huft_free(u[0]);
return 3; /* not enough memory */
}
hufts += z + 1; /* track memory usage */
*t = q + 1; /* link to list for huft_free() */
*(t = &(q->v.t)) = (struct huft *) 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 = (uch) l; /* bits to dump before this table */
r.e = (uch) (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 = (uch) (k - w);
if (p >= v + n)
r.e = 99; /* out of values--invalid code */
else if (*p < s) {
r.e = (uch) (*p < 256 ? 16 : 15); /* 256 is end-of-block code */
r.v.n = (ush) (*p); /* simple code is just the value */
p++; /* one compiler does not like *p++ */
} else {
r.e = (uch) 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;
}
int huft_free(t)
struct huft *t; /* table to free */
/* 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. */
{
register struct huft *p, *q;
/* Go through linked list, freeing from the malloced (t[-1]) address. */
p = t;
while (p != (struct huft *) NULL) {
q = (--p)->v.t;
free((char *) p);
p = q;
}
return 0;
}
int inflate_codes(tl, td, bl, bd)
struct huft *tl, *td; /* literal/length and distance decoder tables */
int bl, bd; /* number of bits decoded by tl[] and td[] */
/* inflate (decompress) the codes in a deflated (compressed) block.
Return an error code or zero if it all goes ok. */
{
register unsigned e; /* table entry flag/number of extra bits */
unsigned n, d; /* length and index for copy */
unsigned w; /* current window position */
struct huft *t; /* pointer to table entry */
unsigned ml, md; /* masks for bl and bd bits */
register ulg 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 = wp; /* 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 */
NEEDBITS((unsigned) bl)
if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
do {
if (e == 99)
return 1;
DUMPBITS(t->b)
e -= 16;
NEEDBITS(e)
} while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e)
> 16);
DUMPBITS(t->b)
if (e == 16) { /* then it's a literal */
slide[w++] = (uch) t->v.n;
Tracevv((stderr, "%c", slide[w - 1]));
if (w == WSIZE) {
flush_output(w);
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 */
NEEDBITS(e)
n = t->v.n + ((unsigned) b & mask_bits[e]);
DUMPBITS(e);
/* decode distance of block to copy */
NEEDBITS((unsigned) bd)
if ((e = (t = td + ((unsigned) b & md))->e) > 16)
do {
if (e == 99)
return 1;
DUMPBITS(t->b)
e -= 16;
NEEDBITS(e)
}
while (
(e =
(t =
t->v.t + ((unsigned) b & mask_bits[e]))->e) >
16);
DUMPBITS(t->b)
NEEDBITS(e)
d = w - t->v.n - ((unsigned) b & mask_bits[e]);
DUMPBITS(e)
Tracevv((stderr, "\\[%d,%d]", w - d, n));
/* 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(slide + w, slide + d, e);
w += e;
d += e;
} else /* do it slow to avoid memcpy() overlap */
#endif /* !NOMEMCPY */
do {
slide[w++] = slide[d++];
Tracevv((stderr, "%c", slide[w - 1]));
} while (--e);
if (w == WSIZE) {
flush_output(w);
w = 0;
}
} while (n);
}
}
/* restore the globals from the locals */
wp = w; /* restore global window pointer */
bb = b; /* restore global bit buffer */
bk = k;
/* done */
return 0;
}
int inflate_stored()
/* "decompress" an inflated type 0 (stored) block. */
{
unsigned n; /* number of bytes in block */
unsigned w; /* current window position */
register ulg 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 = wp; /* initialize window position */
/* go to byte boundary */
n = k & 7;
DUMPBITS(n);
/* get the length and its complement */
NEEDBITS(16)
n = ((unsigned) b & 0xffff);
DUMPBITS(16)
NEEDBITS(16)
if (n != (unsigned) ((~b) & 0xffff))
return 1; /* error in compressed data */
DUMPBITS(16)
/* read and output the compressed data */
while (n--) {
NEEDBITS(8)
slide[w++] = (uch) b;
if (w == WSIZE) {
flush_output(w);
w = 0;
}
DUMPBITS(8)
}
/* restore the globals from the locals */
wp = w; /* restore global window pointer */
bb = b; /* restore global bit buffer */
bk = k;
return 0;
}
int 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 */
struct huft *tl; /* literal/length code table */
struct huft *td; /* distance code table */
int bl; /* lookup bits for tl */
int bd; /* lookup bits for td */
unsigned 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;
}
int inflate_dynamic()
/* decompress an inflated type 2 (dynamic Huffman codes) block. */
{
int i; /* temporary variables */
unsigned j;
unsigned l; /* last length */
unsigned m; /* mask for bit lengths table */
unsigned n; /* number of lengths to get */
struct huft *tl; /* literal/length code table */
struct huft *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 */
#ifdef PKZIP_BUG_WORKAROUND
unsigned ll[288 + 32]; /* literal/length and distance code lengths */
#else
unsigned ll[286 + 30]; /* literal/length and distance code lengths */
#endif
register ulg b; /* bit buffer */
register unsigned k; /* number of bits in bit buffer */
/* make local bit buffer */
b = bb;
k = bk;
/* read in table lengths */
NEEDBITS(5)
nl = 257 + ((unsigned) b & 0x1f); /* number of literal/length codes */
DUMPBITS(5)
NEEDBITS(5)
nd = 1 + ((unsigned) b & 0x1f); /* number of distance codes */
DUMPBITS(5)
NEEDBITS(4)
nb = 4 + ((unsigned) b & 0xf); /* number of bit length codes */
DUMPBITS(4)
#ifdef PKZIP_BUG_WORKAROUND
if (nl > 288 || nd > 32)
#else
if (nl > 286 || nd > 30)
#endif
return 1; /* bad lengths */
/* read in bit-length-code lengths */
for (j = 0; j < nb; j++) {
NEEDBITS(3)
ll[border[j]] = (unsigned) b & 7;
DUMPBITS(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) {
NEEDBITS((unsigned) bl)
j = (td = tl + ((unsigned) b & m))->b;
DUMPBITS(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 */
NEEDBITS(2)
j = 3 + ((unsigned) b & 3);
DUMPBITS(2)
if ((unsigned) i + j > n)
return 1;
while (j--)
ll[i++] = l;
} else if (j == 17) { /* 3 to 10 zero length codes */
NEEDBITS(3)
j = 3 + ((unsigned) b & 7);
DUMPBITS(3)
if ((unsigned) i + j > n)
return 1;
while (j--)
ll[i++] = 0;
l = 0;
} else { /* j == 18: 11 to 138 zero length codes */
NEEDBITS(7)
j = 11 + ((unsigned) b & 0x7f);
DUMPBITS(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;
bk = k;
/* 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) {
fprintf(stderr, " incomplete literal tree\n");
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) {
fprintf(stderr, " incomplete distance tree\n");
#ifdef PKZIP_BUG_WORKAROUND
i = 0;
}
#else
huft_free(td);
}
huft_free(tl);
return i; /* incomplete code set */
#endif
}
/* 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;
}
int inflate_block(e)
int *e; /* last block flag */
/* decompress an inflated block */
{
unsigned t; /* block type */
register ulg 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 */
NEEDBITS(1)
* e = (int) b & 1;
DUMPBITS(1)
/* read in block type */
NEEDBITS(2)
t = (unsigned) b & 3;
DUMPBITS(2)
/* restore the global bit buffer */
bb = b;
bk = k;
/* inflate that block type */
if (t == 2)
return inflate_dynamic();
if (t == 0)
return inflate_stored();
if (t == 1)
return inflate_fixed();
/* bad block type */
return 2;
}
int inflate()
/* decompress an inflated entry */
{
int e; /* last block flag */
int r; /* result code */
unsigned h; /* maximum struct huft's malloc'ed */
/* initialize window, bit buffer */
wp = 0;
bk = 0;
bb = 0;
/* decompress until the last block */
h = 0;
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;
inptr--;
}
/* flush out slide */
flush_output(wp);
/* return success */
#ifdef DEBUG
fprintf(stderr, "<%u> ", h);
#endif /* DEBUG */
return 0;
}
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