gzip.c

GNU 系统开发的基于Iz77语法的压缩 学习lz77压缩算法

/* 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.
 */

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};

/* Compress files with zip algorithm and 'compress' interface.
 * See usage() and help() functions below for all options.
 * Outputs:
 *        file.z:   compressed file with same mode, owner, and utimes
 *        file.Z:   same with -Z option (old compress format)
 *     or stdout with -c option or if stdin used as input.
 * If the OS does not support file names with multiple dots (MSDOS, VMS) or
 * if the output file name had to be truncated, the original name is kept
 * in the compressed .z file. (Feature not available in old compress format.)
 * On MSDOS, file.tmp -> file.tmz. On VMS, file.tmp -> file.tmp-z.
 *
 * For the meaning of all compilation flags, see comments in Makefile.in.
 */

#ifndef lint
static char rcsid[] = "$Id: gzip.c,v 0.17 1993/03/18 18:14:56 jloup Exp $";
#endif

#include "tailor.h"
#include "gzip.h"
#include "lzw.h"
#include "revision.h"
#include "getopt.h"

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/stat.h>
#include <errno.h>

		/* configuration */

#ifndef NO_FCNTL_H
#  include <fcntl.h>
#endif

#ifdef HAVE_UNISTD_H
#  include <unistd.h>
#endif

#if defined(STDC_HEADERS) || !defined(NO_STDLIB_H)
#  include <stdlib.h>
#else
   extern int errno;
#endif

#if defined(DIRENT) || defined(_POSIX_VERSION)
#  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

#ifndef NO_UTIME
#  ifndef NO_UTIME_H
#    include <utime.h>
#    define TIME_OPT "UTIME"
#  else
#    ifdef HAVE_SYS_UTIME_H
#      include <sys/utime.h>
#      define TIME_OPT "SYS_UTIME"
#    else
       struct utimbuf {
         time_t actime;
         time_t modtime;
       };
#      define TIME_OPT ""
#    endif
#  endif
#else
#  define TIME_OPT "NO_UTIME"
#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)();

#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

#define RW_USER 0600    /* creation mode for open() */

#ifndef MAX_PATH_LEN
#  define MAX_PATH_LEN   1024 /* max pathname length */
#endif

#define MAX_HEADER_LEN   16
/* max length of a compressed file header, fixed part only */

		/* 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 to_stdout = 0;    /* output to stdout (-c) */
int decompress = 0;   /* decompress (-d) */
int force = 0;        /* don't ask questions, compress links (-f) */
int recursive = 0;    /* recurse through directories (-r) */
int verbose = 0;      /* be verbose (-v) */
int quiet = 0;        /* be very quiet (-q) */
int quit_on_tty = 0;  /* quit if compressing to or decompressing from a tty */
int do_lzw = 0;       /* generate output compatible with old compress (-Z) */
int test = 0;         /* test .z file integrity */
int foreground;       /* set if program run in foreground */
char *progname;       /* program name */
int maxbits = BITS;   /* max bits per code for LZW */
int method = DEFLATED;/* compression method */
int level = 5;        /* compression level */
int exit_code = OK;   /* program exit code */
int save_orig_name;   /* set if original name must be saved */
int last_member;      /* set for .zip and .Z files */
int part_nb;          /* number of parts in .z file */
ulg time_stamp;       /* original time stamp (modification time) */
long ifile_size;      /* input file size, -1 for devices (debug only) */
char *env;            /* contents of GZIP env variable */
char **args = NULL;   /* argv pointer if GZIP env variable defined */

long bytes_in;             /* number of input bytes */
long bytes_out;            /* number of output bytes */
char ifname[MAX_PATH_LEN]; /* input filename */
char ofname[MAX_PATH_LEN]; /* output filename */
int  remove_ofname = 0;	   /* remove output file on error */
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 */

struct option longopts[] =
{
 /* { name  has_arg  *flag  val } */
 /* {"ascii",      0, 0, 'a'},  ascii text mode */
    {"stdout",     0, 0, 'c'}, /* write output on standard output */
    {"decompress", 0, 0, 'd'}, /* decompress */
    {"uncompress", 0, 0, 'd'}, /* decompress */
 /* {"encrypt",    0, 0, 'e'},    encrypt */
    {"force",      0, 0, 'f'}, /* force overwrite of output file */
    {"help",       0, 0, 'h'}, /* give help */
 /* {"pkzip",      0, 0, 'k'},    force output in pkzip format */
 /* {"list",       0, 0, 'l'},    list .z file contents */
    {"license",    0, 0, 'L'}, /* display software license */
    {"quiet",      0, 0, 'q'}, /* quiet mode */
    {"recurse",    0, 0, 'r'}, /* recurse through directories */
    {"test",       0, 0, 't'}, /* test compressed file integrity */
    {"verbose",    0, 0, 'v'}, /* verbose mode */
    {"version",    0, 0, 'V'}, /* display version number */
    {"fast",       0, 0, '1'}, /* compress faster */
    {"best",       0, 0, '9'}, /* compress better */
    {"lzw",        0, 0, 'Z'}, /* make output compatible with old compress */
    {"bits",       1, 0, 'b'}, /* max number of bits per code (implies -Z) */
    { 0, 0, 0, 0 }
};

/* local functions */

local void usage        OF((void));
local void help         OF((void));
local void license      OF((void));
local void version      OF((void));
local void treat_stdin  OF((void));
local void treat_file   OF((char *iname));
local int create_outfile OF((void));
local int  do_stat      OF((char *name, struct stat *sbuf));
local char *get_suffix  OF((char *name));
local int  get_istat    OF((char *iname, struct stat *sbuf));
local int  make_ofname  OF((void));
local int  same_file    OF((struct stat *stat1, struct stat *stat2));
local int name_too_long OF((char *name, struct stat *statb));
local int  get_method   OF((int in));
local int  check_ofname OF((void));
local void reset_times  OF((char *name, struct stat *statb));
local void copy_stat    OF((struct stat *ifstat));
local void treat_dir    OF((char *dir));
local void do_exit      OF((int exitcode));
      int main          OF((int argc, char **argv));

void (*work) OF((int infile, int outfile)) = zip; /* function to call */

#define strequ(s1, s2) (strcmp((s1),(s2)) == 0)

/* ======================================================================== */
local void usage()
{
    fprintf(stderr,
#ifdef LZW
#  ifdef NO_DIR
            "usage: %s [-cdfhLtvVZ19] [-b maxbits] [file ...]\n",
#  else
            "usage: %s [-cdfhLrtvVZ19] [-b maxbits] [file ...]\n",
#  endif
#else /* !LZW */
#  ifdef NO_DIR
            "usage: %s [-cdfhLtvV19] [file ...]\n",
#  else
            "usage: %s [-cdfhLrtvV19] [file ...]\n",
#  endif
#endif /* LZW */
             progname);
}
/* ======================================================================== */
local void help()
{
    static char  *help_msg[] = {
/* -a --ascii       ascii text; convert end-of-lines to local OS conventions */
 " -c --stdout      write on standard output, keep original files unchanged",
 " -d --decompress  decompress",
/* -e --encrypt     encrypt */
 " -f --force       force overwrite of output file and compress links",
 " -h --help        give this help",
/* -k --pkzip       force output in pkzip format */
/* -l --list        list .z file contents */
 " -L --license     display software license",
 " -q --quiet       suppress all warnings",
#ifndef NO_DIR
 " -r --recurse     recurse through directories",
#endif
 " -t --test        test compressed file integrity",
 " -v --verbose     verbose mode",
 " -V --version     display version number",
 " -1 --fast        compress faster",
 " -9 --best        compress better",
#ifdef LZW
 " -Z --lzw         produce output compatible with old compress",
 " -b --bits maxbits   max number of bits per code (implies -Z)",
#endif
 " file...          files to (de)compress. If none given, use standard input.",
  0};
    char **p = help_msg;

    fprintf(stderr,"%s %s (%s)\n", progname, VERSION, REVDATE);
    usage();
    while (*p) fprintf(stderr, "%s\n", *p++);
}

/* ======================================================================== */
local void license()
{
    char **p = license_msg;

    fprintf(stderr,"%s %s (%s)\n", progname, VERSION, REVDATE);
    while (*p) fprintf(stderr, "%s\n", *p++);
}

/* ======================================================================== */
local void version()
{
    fprintf(stderr,"%s %s (%s)\n", progname, VERSION, REVDATE);

    fprintf(stderr, "Compilation options:\n%s %s ", DIR_OPT, TIME_OPT);
#ifdef STDC_HEADERS
    fprintf(stderr, "STDC_HEADERS ");
#endif
#ifdef HAVE_UNISTD_H
    fprintf(stderr, "HAVE_UNISTD_H ");
#endif
#ifdef NO_MEMORY_H
    fprintf(stderr, "NO_MEMORY_H ");
#endif
#ifdef NO_STRING_H
    fprintf(stderr, "NO_STRING_H ");
#endif
#ifdef NO_SYMLINK
    fprintf(stderr, "NO_SYMLINK ");
#endif
#ifdef NO_MULTIPLE_DOTS
    fprintf(stderr, "NO_MULTIPLE_DOTS ");
#endif
#ifdef NO_CHOWN
    fprintf(stderr, "NO_CHOWN ");
#endif
#ifdef PROTO
    fprintf(stderr, "PROTO ");
#endif
#ifdef ASMV
    fprintf(stderr, "ASMV ");
#endif
#ifdef DEBUG
    fprintf(stderr, "DEBUG ");
#endif
#ifdef DYN_ALLOC
    fprintf(stderr, "DYN_ALLOC ");
#endif
#ifdef MAXSEG_64K
    fprintf(stderr, "MAXSEG_64K");
#endif
    fprintf(stderr, "\n");
}

/* ======================================================================== */
int main (argc, argv)
    int argc;
    char **argv;
{
    int file_count = 0; /* number of files to precess */
    int proglen;        /* length of progname */
    int optc;           /* current option */

    EXPAND(argc, argv); /* wild card expansion if necessary */

    progname = basename(argv[0]);
    proglen = strlen(progname);

    /* Suppress .exe for MSDOS, OS/2 and VMS: */
    if (proglen > 4 && strequ(progname+proglen-4, ".exe")) {
        progname[proglen-4] = '\0';
    }

    /* Add options in GZIP environment variable if there is one */
    env = add_envopt(&argc, &argv, OPTIONS_VAR);
    if (env != NULL) args = argv;

    foreground = signal(SIGINT, SIG_IGN) != SIG_IGN;
    if (foreground) {
	signal (SIGINT, (sig_type)abort_gzip);
    }
#ifdef SIGTERM
    signal(SIGTERM, (sig_type)abort_gzip);
#endif
#ifdef SIGHUP
    signal(SIGHUP,  (sig_type)abort_gzip);
#endif

#ifndef GNU_STANDARD
    /* For compatibility with old compress, use program name as an option.
     * If you compile with -DGNU_STANDARD, this program will behave as
     * gzip even if it is invoked under the name gunzip or zcat.
     *
     * Systems which do not support links can still use -d or -dc.
     * Ignore an .exe extension for MSDOS, OS/2 and VMS.
     */
    if (  strncmp(progname, "un",  2) == 0     /* ungzip, uncompress */
       || strncmp(progname, "gun", 3) == 0) {  /* gunzip */
	decompress = 1;
    } else if (strequ(progname+1, "cat")       /* zcat, pcat */
	    || strequ(progname, "gzcat")) {    /* gzcat */
	decompress = to_stdout = 1;
    }
#endif

    while ((optc = getopt_long (argc, argv, "b:cdfhLqrtvVZ123456789",
				longopts, (int *)0)) != EOF) {
	switch (optc) {
	case 'b':
	    maxbits = atoi(optarg);
	    break;
	case 'c':
	    to_stdout = 1; break;
	case 'd':
	    decompress = 1; break;
	case 'f':
	    force++; break;
	case 'h':
	    help(); do_exit(OK); break;
	case 'L':
	    license(); do_exit(OK); break;
	case 'q':
	    quiet = 1; verbose = 0; break;
	case 'r':
#ifdef NO_DIR
	    fprintf(stderr, "%s: -r not supported on this system\n", progname);
	    usage();
	    do_exit(ERROR); break;
#else
	    recursive = 1; break;
#endif
	case 't':
	    test = decompress = to_stdout = 1;
	    break;
	case 'v':
	    verbose++; quiet = 0; break;
	case 'V':
	    version(); quit_on_tty = 1; break;
	case 'Z':
#ifdef LZW
	    do_lzw = 1; break;
#else
	    fprintf(stderr, "%s: -Z not supported in this version\n",
		    progname);