zip.c

给出了 zip 压缩算法的完整实现过程。

#ifndef USE_ZIPMAIN
int main(argc, argv)
#else
int zipmain(argc, argv)
#endif
int argc;               /* number of tokens in command line */
char **argv;            /* command line tokens */
/* Add, update, freshen, or delete zip entries in a zip file.  See the
   command help in help() above. */
{
  int a;                /* attributes of zip file */
  ulg c;                /* start of central directory */
  int d;                /* true if just adding to a zip file */
  char *e;              /* malloc'd comment buffer */
  struct flist far *f;  /* steps through found linked list */
  int i;                /* arg counter, root directory flag */
  int k;                /* next argument type, marked counter,
                           comment size, entry count */
  ulg n;                /* total of entry len's */
  int o;                /* true if there were any ZE_OPEN errors */
  char *p;              /* steps through option arguments */
  char *pp;             /* temporary pointer */
  ulg *cmptime = NULL;  /* pointer to 'before' or 'after' */
  int r;                /* temporary variable */
  int s;                /* flag to read names from stdin */
  ulg t;                /* file time, length of central directory */
  int first_listarg = 0;/* index of first arg of "process these files" list */
  struct zlist far *v;  /* temporary variable */
  struct zlist far * far *w;    /* pointer to last link in zfiles list */
  FILE *x, *y;          /* input and output zip files */
  struct zlist far *z;  /* steps through zfiles linked list */
  int bad_open_is_error = 0; /* if open read fails, 0=warning, 1=error */
#ifdef WINDLL
  int retcode;          /* return code for dll */
#endif
#if (!defined(VMS) && !defined(CMS_MVS))
  char *zipbuf;         /* stdio buffer for the zip file */
#endif /* !VMS && !CMS_MVS */
  FILE *comment_stream; /* set to stderr if anything is read from stdin */

#ifdef THEOS
  /* the argument expansion from the standard library is full of bugs */
  /* use mine instead */
  _setargv(&argc, &argv);
  setlocale(LC_CTYPE,"I");
#else
  SETLOCALE(LC_CTYPE,"");
#endif

#if defined(__IBMC__) && defined(__DEBUG_ALLOC__)
  {
    extern void DebugMalloc(void);
    atexit(DebugMalloc);
  }
#endif

#ifdef QDOS
  {
    extern void QDOSexit(void);
    atexit(QDOSexit);
  }
#endif

#ifdef RISCOS
  set_prefix();
#endif

#ifdef __human68k__
  fflush(stderr);
  setbuf(stderr, NULL);
#endif

/* Re-initialize global variables to make the zip dll re-entrant. It is
 * possible that we could get away with not re-initializing all of these
 * but better safe than sorry.
 */
#if defined(MACOS) || defined(WINDLL)
  action = ADD; /* one of ADD, UPDATE, FRESHEN, or DELETE */
  comadd = 0;   /* 1=add comments for new files */
  zipedit = 0;  /* 1=edit zip comment and all file comments */
  latest = 0;   /* 1=set zip file time to time of latest file */
  before = 0;   /* 0=ignore, else exclude files before this time */
  after = 0;    /* 0=ignore, else exclude files newer than this time */
  test = 0;     /* 1=test zip file with unzip -t */
  tempdir = 0;  /* 1=use temp directory (-b) */
  junk_sfx = 0; /* 1=junk the sfx prefix */
#if defined(AMIGA) || defined(MACOS)
  filenotes = 0;/* 1=take comments from AmigaDOS/MACOS filenotes */
#endif
  zipstate = -1;
  tempzip = NULL;
  fcount = 0;
  recurse = 0;         /* 1=recurse into directories; 2=match filenames */
  dispose = 0;         /* 1=remove files after put in zip file */
  pathput = 1;         /* 1=store path with name */
  method = BEST;       /* one of BEST, DEFLATE (only), or STORE (only) */
  dosify = 0;          /* 1=make new entries look like MSDOS */
  verbose = 0;         /* 1=report oddities in zip file structure */
  fix = 0;             /* 1=fix the zip file */
  adjust = 0;          /* 1=adjust offsets for sfx'd file (keep preamble) */
  level = 6;           /* 0=fastest compression, 9=best compression */
  translate_eol = 0;   /* Translate end-of-line LF -> CR LF */
#if defined(OS2) || defined(WIN32)
  use_longname_ea = 0; /* 1=use the .LONGNAME EA as the file's name */
#endif
#ifdef NTSD_EAS
  use_privileges = 0;  /* 1=use security privileges overrides */
#endif
  hidden_files = 0;    /* process hidden and system files */
  volume_label = 0;    /* add volume label */
  dirnames = 1;        /* include directory entries by default */
  linkput = 0;         /* 1=store symbolic links as such */
  noisy = 1;           /* 0=quiet operation */
  extra_fields = 1;    /* 0=do not create extra fields */
  special = ".Z:.zip:.zoo:.arc:.lzh:.arj"; /* List of special suffixes */
  key = NULL;          /* Scramble password if scrambling */
  tempath = NULL;      /* Path for temporary files */
  found = NULL;        /* where in found, or new found entry */
  fnxt = &found;
  patterns = NULL;     /* List of patterns to be matched */
  pcount = 0;          /* number of patterns */
  icount = 0;          /* number of include only patterns */
  Rcount = 0;          /* number of -R include patterns */
  bad_open_is_error = 0; /* if read fails, 0=warning, 1=error */

#ifndef MACOS
  retcode = setjmp(zipdll_error_return);
  if (retcode) {
    return retcode;
  }
#endif /* !MACOS */
#endif /* MACOS || WINDLL */

  mesg = (FILE *) stdout; /* cannot be made at link time for VMS */
  comment_stream = (FILE *)stdin;

  init_upper();           /* build case map table */

#if (defined(WIN32) && defined(USE_EF_UT_TIME))
  /* For the Win32 environment, we may have to "prepare" the environment
     prior to the tzset() call, to work around tzset() implementation bugs.
   */
  iz_w32_prepareTZenv();
#endif

#if (defined(IZ_CHECK_TZ) && defined(USE_EF_UT_TIME))
#  ifndef VALID_TIMEZONE
#     define VALID_TIMEZONE(tmp) \
             (((tmp = getenv("TZ")) != NULL) && (*tmp != '\0'))
#  endif
  zp_tz_is_valid = VALID_TIMEZONE(p);
#if (defined(AMIGA) || defined(DOS))
  if (!zp_tz_is_valid)
    extra_fields = 0;     /* disable storing "UT" time stamps */
#endif /* AMIGA || DOS */
#endif /* IZ_CHECK_TZ && USE_EF_UT_TIME */

/* For systems that do not have tzset() but supply this function using another
   name (_tzset() or something similar), an appropiate "#define tzset ..."
   should be added to the system specifc configuration section.  */
#if (!defined(TOPS20) && !defined(VMS))
#if (!defined(RISCOS) && !defined(MACOS) && !defined(QDOS))
#if (!defined(BSD) && !defined(MTS) && !defined(CMS_MVS) && !defined(TANDEM))
  tzset();
#endif
#endif
#endif

#ifdef VMSCLI
    {
        ulg status = vms_zip_cmdline(&argc, &argv);
        if (!(status & 1))
            return status;
    }
#endif /* VMSCLI */

  /* extract extended argument list from environment */
  expand_args(&argc, &argv);


#ifndef WINDLL
  /* Process arguments */
  diag("processing arguments");
  /* First, check if just the help or version screen should be displayed */
  if (argc == 1 && isatty(1))   /* no arguments, and output screen available */
  {                             /* show help screen */
#ifdef VMSCLI
    VMSCLI_help();
#else
    help();
#endif
    EXIT(ZE_OK);
  }
  else if (argc == 2 && strcmp(argv[1], "-v") == 0 &&
           /* only "-v" as argument, and */
           (isatty(1) || isatty(0)))
           /* stdout or stdin is connected to console device */
  {                             /* show diagnostic version info */
    version_info();
    EXIT(ZE_OK);
  }
#ifndef VMS
#  ifndef RISCOS
  envargs(&argc, &argv, "ZIPOPT", "ZIP");  /* get options from environment */
#  else /* RISCOS */
  envargs(&argc, &argv, "ZIPOPT", "Zip$Options");  /* get options from environment */
  getRISCOSexts("Zip$Exts");        /* get the extensions to swap from environment */
#  endif /* ? RISCOS */
#else /* VMS */
  envargs(&argc, &argv, "ZIPOPT", "ZIP_OPTS");  /* 4th arg for unzip compat. */
#endif /* ?VMS */
#endif /* !WINDLL */

  zipfile = tempzip = NULL;
  tempzf = NULL;
  d = 0;                        /* disallow adding to a zip file */
#if (!defined(MACOS) && !defined(WINDLL))
   signal(SIGINT, handler);
# ifdef SIGTERM                  /* AMIGADOS and others have no SIGTERM */
   signal(SIGTERM, handler);
# endif
# if defined(SIGABRT) && !(defined(AMIGA) && defined(__SASC))
   signal(SIGABRT, handler);
# endif
# ifdef SIGBREAK
   signal(SIGBREAK, handler);
# endif
# ifdef SIGBUS
   signal(SIGBUS, handler);
# endif
# ifdef SIGILL
   signal(SIGILL, handler);
# endif
# ifdef SIGSEGV
   signal(SIGSEGV, handler);
# endif
#endif /* !MACOS && !WINDLL */
  k = 0;                        /* Next non-option argument type */
  s = 0;                        /* set by -@ if -@ is early */

  r = get_filters(argc, argv);      /* scan first the -x and -i patterns */
#ifdef WINDLL
  if (r != ZE_OK)
    return r;
#endif

  for (i = 1; i < argc; i++)
  {
    if (argv[i][0] == '-')
    {
      if (argv[i][1])
        for (p = argv[i]+1; *p; p++)
          switch (*p)
          {
#ifdef EBCDIC
            case 'a':
              aflag = ASCII;
              printf("Translating to ASCII...\n");
              break;
#endif /* EBCDIC */
#ifdef CMS_MVS
            case 'B':
              bflag = 1;
              printf("Using binary mode...\n");
              break;
#endif /* CMS_MVS */
#ifdef TANDEM
            case 'B':
              nskformatopt(&p);
              break;
#endif
            case '0':
              method = STORE; level = 0; break;
            case '1':  case '2':  case '3':  case '4':
            case '5':  case '6':  case '7':  case '8':  case '9':
                        /* Set the compression efficacy */
              level = *p - '0';  break;
            case 'A':   /* Adjust unzipsfx'd zipfile:  adjust offsets only */
              adjust = 1; break;
            case 'b':   /* Specify path for temporary file */
              tempdir = 1;
              if (k != 0) {
                ZIPERR(ZE_PARMS, "use -b before zip file name");
              }
              else
                k = 1;          /* Next non-option is path */
              break;
            case 'c':   /* Add comments for new files in zip file */
              comadd = 1;  break;
            case 'd':   /* Delete files from zip file */
#ifdef MACOS
              if (p[1] == 'f') {
                ++p;
                MacZip.DataForkOnly = true;
              } else
#endif /* MACOS */
              {
                if (action != ADD) {
                  ZIPERR(ZE_PARMS, "specify just one action");
                }
                action = DELETE;
                break;
              }
            case 'D':   /* Do not add directory entries */
              dirnames = 0; break;
            case 'e':   /* Encrypt */
#if !CRYPT
              ZIPERR(ZE_PARMS, "encryption not supported");
#else /* CRYPT */
              if (key == NULL) {
                if ((key = malloc(IZ_PWLEN+1)) == NULL) {
                  ZIPERR(ZE_MEM, "was getting encryption password");
                }
                r = encr_passwd(ZP_PW_ENTER, key, IZ_PWLEN+1, zipfile);
                if (r != IZ_PW_ENTERED) {
                  if (r < IZ_PW_ENTERED)
                    r = ZE_PARMS;
                  ZIPERR(r, "was getting encryption password");
                }
                if (*key == '\0') {
                  ZIPERR(ZE_PARMS, "zero length password not allowed");
                }
                if ((e = malloc(IZ_PWLEN+1)) == NULL) {
                  ZIPERR(ZE_MEM, "was verifying encryption password");
                }
                r = encr_passwd(ZP_PW_VERIFY, e, IZ_PWLEN+1, zipfile);
                if (r != IZ_PW_ENTERED && r != IZ_PW_SKIPVERIFY) {
                  free((zvoid *)e);
                  if (r < ZE_OK) r = ZE_PARMS;
                  ZIPERR(r, "was verifying encryption password");
                }
                r = ((r == IZ_PW_SKIPVERIFY) ? 0 : strcmp(key, e));
                free((zvoid *)e);
                if (r) {
                  ZIPERR(ZE_PARMS, "password verification failed");
                }
              }
#endif /* !CRYPT */
              break;
            case 'F':   /* fix the zip file */
              fix++; break;
            case 'f':   /* Freshen zip file--overwrite only */
              if (action != ADD) {
                ZIPERR(ZE_PARMS, "specify just one action");
              }
              action = FRESHEN;
              break;
            case 'g':   /* Allow appending to a zip file */
              d = 1;  break;
#ifndef WINDLL
            case 'h': case 'H': case '?':  /* Help */
#ifdef VMSCLI
              VMSCLI_help();
#else
              help();
#endif
              RETURN(finish(ZE_OK));
#endif /* !WINDLL */

#ifdef RISCOS
            case 'I':   /* Don't scan through Image files */
              scanimage = 0;
              break;
#endif
#ifdef MACOS
            case 'j':   /* Junk path / Store absolute path */
              if (p[1] == 'j') {    /* store absolute path including volname */
                ++p;
                MacZip.StoreFullPath = true;
              } else {              /* junk directory names */
                pathput = 0;  break;
              }
#else /* !MACOS */
            case 'j':   /* Junk directory names */
              pathput = 0;  break;
#endif /* ?MACOS */
            case 'J':   /* Junk sfx prefix */
              junk_sfx = 1;  break;
            case 'k':   /* Make entries using DOS names (k for Katz) */
              dosify = 1;  break;
            case 'l':   /* Translate end-of-line */
              translate_eol++; break;
#ifndef WINDLL
            case 'L':   /* Show license */
              license();
              RETURN(finish(ZE_OK));
#endif
            case 'm':   /* Delete files added or updated in zip file */
              dispose++;
              if (dispose == 2)
                ZIPERR(ZE_PARMS, "mm not supported");
              break;
            case 'M':   /* Read failures (misses) are errors instead of warnings */
              bad_open_is_error++;
              break;
            case 'n':   /* Don't compress files with a special suffix */
              special = NULL; /* will be set at next argument */
              break;
#if defined(AMIGA) || defined(MACOS)
            case 'N':   /* Get zipfile comments from AmigaDOS/MACOS filenotes */
              filenotes = 1; break;
#endif
            case 'o':   /* Set zip file time to time of latest file in it */
              latest = 1;  break;
            case 'p':   /* Store path with name */
              break;            /* (do nothing as annoyance avoidance) */
            case 'P':   /* password for encryption */
              if (k != 0) {
                ZIPERR(ZE_PARMS, "use -P before zip file name");
              }
              if (key != NULL) {
                ZIPERR(ZE_PARMS, "can only have one -P");
              }
#if CRYPT
              k = 7;
#else
              ZIPERR(ZE_PARMS, "encryption not supported");
#endif /* CRYPT */
              break;
#if defined(QDOS) || defined(QLZIP)
            case 'Q':
              qlflag  = strtol((p+1), &p, 10);
              if (qlflag == 0) qlflag = 4;
              p--;
              break;
#endif
            case 'q':   /* Quiet operation */
              noisy = 0;
#ifdef MACOS
              MacZip.MacZip_Noisy = false;
#endif  /* MACOS */
              if (verbose) verbose--;
              break;
            case 'r':   /* Recurse into subdirectories, match full path */
              if (recurse == 2) {
                ZIPERR(ZE_PARMS, "do not specify both -r and -R");
              }
              recurse = 1;  break;
            case 'R':   /* Recurse into subdirectories, match filename */
              if (recurse == 1) {
                ZIPERR(ZE_PARMS, "do not specify both -r and -R");