zip.c

给出了 zip 压缩算法的完整实现过程。

/*
  Copyright (c) 1990-2006 Info-ZIP.  All rights reserved.

  See the accompanying file LICENSE, version 2005-Feb-10 or later
  (the contents of which are also included in zip.h) for terms of use.
  If, for some reason, all these files are missing, the Info-ZIP license
  also may be found at:  ftp://ftp.info-zip.org/pub/infozip/license.html
*/
/*
 *  zip.c by Mark Adler.
 */
#define __ZIP_C

#include "zip.h"
#include <time.h>       /* for tzset() declaration */
#ifdef WINDLL
#  include <windows.h>
#  include <setjmp.h>
#  include "windll/windll.h"
#endif
#define DEFCPYRT        /* main module: enable copyright string defines! */
#include "revision.h"
#include "crypt.h"
#include "ttyio.h"
#ifdef VMS
#  include <stsdef.h>
#  include "vms/vmsmunch.h"
#endif

#ifdef MACOS
#  include "macglob.h"
   extern MacZipGlobals MacZip;
   extern int error_level;
#endif

#if (defined(MSDOS) && !defined(__GO32__)) || defined(__human68k__)
#  include <process.h>
#  if (!defined(P_WAIT) && defined(_P_WAIT))
#    define P_WAIT _P_WAIT
#  endif
#endif

#include <signal.h>

#define MAXCOM 256      /* Maximum one-line comment size */


/* Local option flags */
#ifndef DELETE
#define DELETE  0
#endif
#define ADD     1
#define UPDATE  2
#define FRESHEN 3
local int action = ADD; /* one of ADD, UPDATE, FRESHEN, or DELETE */
local int comadd = 0;   /* 1=add comments for new files */
local int zipedit = 0;  /* 1=edit zip comment and all file comments */
local int latest = 0;   /* 1=set zip file time to time of latest file */
local ulg before = 0;   /* 0=ignore, else exclude files before this time */
local ulg after = 0;    /* 0=ignore, else exclude files newer than this time */
local int test = 0;     /* 1=test zip file with unzip -t */
local int tempdir = 0;  /* 1=use temp directory (-b) */
local int junk_sfx = 0; /* 1=junk the sfx prefix */
#if defined(AMIGA) || defined(MACOS)
local int filenotes = 0; /* 1=take comments from AmigaDOS/MACOS filenotes */
#endif

#ifdef EBCDIC
int aflag = __EBCDIC;   /* Convert EBCDIC to ASCII or stay EBCDIC ? */
#endif
#ifdef CMS_MVS
int bflag = 0;          /* Use text mode as default */
#endif

#ifdef QDOS
char _version[] = VERSION;
#endif

#ifdef WINDLL
jmp_buf zipdll_error_return;
#endif

/* Temporary zip file name and file pointer */
#ifndef MACOS
local char *tempzip;
local FILE *tempzf;
#else
char *tempzip;
FILE *tempzf;
#endif

#if CRYPT
/* Pointer to crc_table, needed in crypt.c */
# if (!defined(USE_ZLIB) || defined(USE_OWN_CRCTAB))
ZCONST ulg near *crc_32_tab;
# else
ZCONST uLongf *crc_32_tab;
# endif
#endif /* CRYPT */

/* Local functions */

local void freeup  OF((void));
local int  finish  OF((int));
#if (!defined(MACOS) && !defined(WINDLL))
local void handler OF((int));
local void license OF((void));
#ifndef VMSCLI
local void help    OF((void));
#endif /* !VMSCLI */
#endif /* !MACOS && !WINDLL */
local int get_filters OF((int argc, char **argv));
#if (!defined(MACOS) && !defined(WINDLL))
local void check_zipfile OF((char *zipname, char *zippath));
local void version_info OF((void));
local void zipstdout OF((void));
#endif /* !MACOS && !WINDLL */

local void freeup()
/* Free all allocations in the 'found' list, the 'zfiles' list and
   the 'patterns' list. */
{
  struct flist far *f;  /* steps through found list */
  struct zlist far *z;  /* pointer to next entry in zfiles list */

  for (f = found; f != NULL; f = fexpel(f))
    ;
  while (zfiles != NULL)
  {
    z = zfiles->nxt;
    if (zfiles->zname && zfiles->zname != zfiles->name)
      free((zvoid *)(zfiles->zname));
    if (zfiles->name)
      free((zvoid *)(zfiles->name));
    if (zfiles->iname)
      free((zvoid *)(zfiles->iname));
    if (zfiles->cext && zfiles->cextra && zfiles->cextra != zfiles->extra)
      free((zvoid *)(zfiles->cextra));
    if (zfiles->ext && zfiles->extra)
      free((zvoid *)(zfiles->extra));
    if (zfiles->com && zfiles->comment)
      free((zvoid *)(zfiles->comment));
    farfree((zvoid far *)zfiles);
    zfiles = z;
    zcount--;
  }

  if (patterns != NULL) {
    while (pcount-- > 0) {
      if (patterns[pcount].zname != NULL)
        free((zvoid *)(patterns[pcount].zname));
    }
    free((zvoid *)patterns);
    patterns = NULL;
  }
}

local int finish(e)
int e;                  /* exit code */
/* Process -o and -m options (if specified), free up malloc'ed stuff, and
   exit with the code e. */
{
  int r;                /* return value from trash() */
  ulg t;                /* latest time in zip file */
  struct zlist far *z;  /* pointer into zfile list */

  /* If latest, set time to zip file to latest file in zip file */
  if (latest && zipfile && strcmp(zipfile, "-"))
  {
    diag("changing time of zip file to time of latest file in it");
    /* find latest time in zip file */
    if (zfiles == NULL)
       zipwarn("zip file is empty, can't make it as old as latest entry", "");
    else {
      t = 0;
      for (z = zfiles; z != NULL; z = z->nxt)
        /* Ignore directories in time comparisons */
#ifdef USE_EF_UT_TIME
        if (z->iname[z->nam-1] != (char)0x2f)   /* ascii '/' */
        {
          iztimes z_utim;
          ulg z_tim;

          z_tim = ((get_ef_ut_ztime(z, &z_utim) & EB_UT_FL_MTIME) ?
                   unix2dostime(&z_utim.mtime) : z->tim);
          if (t < z_tim)
            t = z_tim;
        }
#else /* !USE_EF_UT_TIME */
        if (z->iname[z->nam-1] != (char)0x2f    /* ascii '/' */
            && t < z->tim)
          t = z->tim;
#endif /* ?USE_EF_UT_TIME */
      /* set modified time of zip file to that time */
      if (t != 0)
        stamp(zipfile, t);
      else
        zipwarn(
         "zip file has only directories, can't make it as old as latest entry",
         "");
    }
  }
  if (tempath != NULL)
  {
    free((zvoid *)tempath);
    tempath = NULL;
  }
  if (zipfile != NULL)
  {
    free((zvoid *)zipfile);
    zipfile = NULL;
  }
  if (zcomment != NULL)
  {
    free((zvoid *)zcomment);
    zcomment = NULL;
  }


  /* If dispose, delete all files in the zfiles list that are marked */
  if (dispose)
  {
    diag("deleting files that were added to zip file");
    if ((r = trash()) != ZE_OK)
      ZIPERR(r, "was deleting moved files and directories");
  }


  /* Done! */
  freeup();
  return e;
}

void ziperr(c, h)
int c;                  /* error code from the ZE_ class */
ZCONST char *h;         /* message about how it happened */
/* Issue a message for the error, clean up files and memory, and exit. */
{
#ifndef WINDLL
#ifndef MACOS
  static int error_level = 0;
#endif

  if (error_level++ > 0)
     /* avoid recursive ziperr() printouts (his should never happen) */
     EXIT(ZE_LOGIC);  /* ziperr recursion is an internal logic error! */
#endif /* !WINDLL */

  if (h != NULL) {
    if (PERR(c))
      perror("zip I/O error");
    fflush(mesg);
    fprintf(stderr, "\nzip error: %s (%s)\n", ziperrors[c-1], h);
#ifdef DOS
    check_for_windows("Zip");
#endif
  }
  if (tempzip != NULL)
  {
    if (tempzip != zipfile) {
      if (tempzf != NULL)
        fclose(tempzf);
#ifndef DEBUG
      destroy(tempzip);
#endif
      free((zvoid *)tempzip);
    } else {
      /* -g option, attempt to restore the old file */
      int k = 0;                        /* keep count for end header */
      ulg cb = cenbeg;                  /* get start of central */
      struct zlist far *z;  /* steps through zfiles linked list */

      fprintf(stderr, "attempting to restore %s to its previous state\n",
         zipfile);
      fseek(tempzf, cenbeg, SEEK_SET);
      tempzn = cenbeg;
      for (z = zfiles; z != NULL; z = z->nxt)
      {
        putcentral(z, tempzf);
        tempzn += 4 + CENHEAD + z->nam + z->cext + z->com;
        k++;
      }
      putend(k, tempzn - cb, cb, zcomlen, zcomment, tempzf);
      fclose(tempzf);
      tempzf = NULL;
    }
  }
  if (key != NULL) {
    free((zvoid *)key);
    key = NULL;
  }
  if (tempath != NULL) {
    free((zvoid *)tempath);
    tempath = NULL;
  }
  if (zipfile != NULL) {
    free((zvoid *)zipfile);
    zipfile = NULL;
  }
  if (zcomment != NULL) {
    free((zvoid *)zcomment);
    zcomment = NULL;
  }
  freeup();
#ifndef WINDLL
  EXIT(c);
#else
  longjmp(zipdll_error_return, c);
#endif
}


void error(h)
  ZCONST char *h;
/* Internal error, should never happen */
{
  ziperr(ZE_LOGIC, h);
}

#if (!defined(MACOS) && !defined(WINDLL))
local void handler(s)
int s;                  /* signal number (ignored) */
/* Upon getting a user interrupt, turn echo back on for tty and abort
   cleanly using ziperr(). */
{
#if defined(AMIGA) && defined(__SASC)
   _abort();
#else
#if !defined(MSDOS) && !defined(__human68k__) && !defined(RISCOS)
  echon();
  putc('\n', stderr);
#endif /* !MSDOS */
#endif /* AMIGA && __SASC */
  ziperr(ZE_ABORT, "aborting");
  s++;                                  /* keep some compilers happy */
}
#endif /* !MACOS && !WINDLL */

void zipwarn(a, b)
ZCONST char *a, *b;     /* message strings juxtaposed in output */
/* Print a warning message to stderr and return. */
{
  if (noisy) {
    fprintf(stderr, "\tzip warning: %s%s\n", a, b);
    fflush(stderr);
  }
}

#ifndef WINDLL
local void license()
/* Print license information to stdout. */
{
  extent i;             /* counter for copyright array */

#if 0
  for (i = 0; i < sizeof(copyright)/sizeof(char *); i++) {
    printf(copyright[i], "zip");
    putchar('\n');
  }
#endif
  for (i = 0; i < sizeof(swlicense)/sizeof(char *); i++)
    puts(swlicense[i]);
}

#ifdef VMSCLI
void help()
#else
local void help()
#endif
/* Print help (along with license info) to stdout. */
{
  extent i;             /* counter for help array */

  /* help array */
  static ZCONST char *text[] = {
#ifdef VMS
"Zip %s (%s). Usage: zip==\"$disk:[dir]zip.exe\"",
#else
"Zip %s (%s). Usage:",
#endif
#ifdef MACOS
"zip [-options] [-b fm] [-t mmddyyyy] [-n suffixes] [zipfile list] [-xi list]",
"  The default action is to add or replace zipfile entries from list.",
" ",
"  -f   freshen: only changed files  -u   update: only changed or new files",
"  -d   delete entries in zipfile    -m   move into zipfile (delete files)",
"  -r   recurse into directories     -j   junk (don't record) directory names",
"  -0   store only                   -l   convert LF to CR LF (-ll CR LF to LF)",
"  -1   compress faster              -9   compress better",
"  -q   quiet operation              -v   verbose operation/print version info",
"  -c   add one-line comments        -z   add zipfile comment",
"                                    -o   make zipfile as old as latest entry",
"  -F   fix zipfile (-FF try harder) -D   do not add directory entries",
"  -T   test zipfile integrity       -X   eXclude eXtra file attributes",
#  if CRYPT
"  -e   encrypt                      -n   don't compress these suffixes"
#  else
"  -h   show this help               -n   don't compress these suffixes"
#  endif
," ",
"  Macintosh specific:",
"  -jj  record Fullpath (+ Volname)  -N store finder-comments as comments",
"  -df  zip only datafork of a file  -S include finder invisible/system files"
#else /* !MACOS */
#ifdef VM_CMS
"zip [-options] [-b fm] [-t mmddyyyy] [-n suffixes] [zipfile list] [-xi list]",
#else  /* !VM_CMS */
"zip [-options] [-b path] [-t mmddyyyy] [-n suffixes] [zipfile list] [-xi list]",
#endif /* ?VM_CMS */
"  The default action is to add or replace zipfile entries from list, which",
"  can include the special name - to compress standard input.",
"  If zipfile and list are omitted, zip compresses stdin to stdout.",
"  -f   freshen: only changed files  -u   update: only changed or new files",
"  -d   delete entries in zipfile    -m   move into zipfile (delete files)",
"  -r   recurse into directories     -j   junk (don't record) directory names",
#ifdef THEOS
"  -0   store only                   -l   convert CR to CR LF (-ll CR LF to CR)",
#else
"  -0   store only                   -l   convert LF to CR LF (-ll CR LF to LF)",
#endif
"  -1   compress faster              -9   compress better",
"  -q   quiet operation              -v   verbose operation/print version info",
"  -c   add one-line comments        -z   add zipfile comment",
"  -@   read names from stdin        -o   make zipfile as old as latest entry",
"  -x   exclude the following names  -i   include only the following names",
#ifdef EBCDIC
#ifdef CMS_MVS
"  -a   translate to ASCII           -B   force binary read (text is default)",
#else  /* !CMS_MVS */
"  -a   translate to ASCII",
#endif /* ?CMS_MVS */
#endif /* EBCDIC */
#ifdef TANDEM
"                                    -Bn  set Enscribe formatting options",
#endif
#ifdef VMS
" \"-F\"  fix zipfile(\"-FF\" try harder) \"-D\"  do not add directory entries",
" \"-A\"  adjust self-extracting exe  \"-J\"  junk zipfile prefix (unzipsfx)",
" \"-T\"  test zipfile integrity      \"-X\"  eXclude eXtra file attributes",
" \"-V\"  save VMS file attributes (\"-VV\" also save allocated blocks past EOF)",
#else /* !VMS */
"  -F   fix zipfile (-FF try harder) -D   do not add directory entries",