zip.c

给出了 zip 压缩算法的完整实现过程。

      if (action == DELETE) {
        /* only delete files in date range */
#ifdef USE_EF_UT_TIME
        z_tim = (get_ef_ut_ztime(z, &z_utim) & EB_UT_FL_MTIME) ?
                unix2dostime(&z_utim.mtime) : z->tim;
#else /* !USE_EF_UT_TIME */
#       define z_tim  z->tim
#endif /* ?USE_EF_UT_TIME */
        if (z_tim < before || (after && z_tim >= after)) {
          /* include in archive */
          z->mark = 0;
        } else {
          /* delete file */
          k++;
        }
      } else if (
#ifdef USE_EF_UT_TIME
          ((t = filetime(z->name, (ulg *)NULL, (long *)NULL, &f_utim))
#else /* !USE_EF_UT_TIME */
          ((t = filetime(z->name, (ulg *)NULL, (long *)NULL, (iztimes *)NULL))
#endif /* ?USE_EF_UT_TIME */
              == 0 ||
           t < before || (after && t >= after) ||
           ((action == UPDATE || action == FRESHEN) &&
#ifdef USE_EF_UT_TIME
            ((get_ef_ut_ztime(z, &z_utim) & EB_UT_FL_MTIME) ?
             f_utim.mtime <= ROUNDED_TIME(z_utim.mtime) : t <= z->tim)
#else /* !USE_EF_UT_TIME */
            t <= z->tim
#endif /* ?USE_EF_UT_TIME */
           )))
      {
        z->mark = comadd ? 2 : 0;
        z->trash = t && t >= before &&
                   (after == 0 || t < after);   /* delete if -um or -fm */
        if (verbose) {
          fprintf(mesg, "zip diagnostic: %s %s\n", z->zname,
                 z->trash ? "up to date" : "missing or early");
        }
      }
      else
        k++;
    }

  /* Remove entries from found list that do not exist or are too old */
  diag("stating new entries");
  Trace((stderr, "zip diagnostic: fcount=%u\n", (unsigned)fcount));
  for (f = found; f != NULL;) {
    Trace((stderr, "zip diagnostic: new file=%s\n", f->zname));
    if (action == DELETE || action == FRESHEN ||
        (t = filetime(f->name, (ulg *)NULL, (long *)NULL, (iztimes *)NULL))
           == 0 ||
        t < before || (after && t >= after) ||
        (namecmp(f->zname, zipfile) == 0 && strcmp(zipfile, "-")))
      f = fexpel(f);
    else
      f = f->nxt;
  }
#ifdef MACOS
  PrintStatProgress("done");
#endif

  /* Make sure there's something left to do */
  if (k == 0 && found == NULL &&
      !(zfiles != NULL &&
        (latest || fix || adjust || junk_sfx || comadd || zipedit))) {
    if (test && (zfiles != NULL || zipbeg != 0)) {
#ifndef WINDLL
      check_zipfile(zipfile, argv[0]);
#endif
      RETURN(finish(ZE_OK));
    }
    if (action == UPDATE || action == FRESHEN) {
      RETURN(finish(ZE_NONE));
    }
    else if (zfiles == NULL && (latest || fix || adjust || junk_sfx)) {
      ZIPERR(ZE_NAME, zipfile);
    }
#ifndef WINDLL
    else if (recurse && (pcount == 0) && (first_listarg > 0)) {
#ifdef VMS
      strcpy(errbuf, "try: zip \"");
      for (i = 1; i < (first_listarg - 1); i++)
        strcat(strcat(errbuf, argv[i]), "\" ");
      strcat(strcat(errbuf, argv[i]), " *.* -i");
#else /* !VMS */
      strcpy(errbuf, "try: zip");
      for (i = 1; i < first_listarg; i++)
        strcat(strcat(errbuf, " "), argv[i]);
#  ifdef AMIGA
      strcat(errbuf, " \"\" -i");
#  else
      strcat(errbuf, " . -i");
#  endif
#endif /* ?VMS */
      for (i = first_listarg; i < argc; i++)
        strcat(strcat(errbuf, " "), argv[i]);
      ZIPERR(ZE_NONE, errbuf);
    }
#endif /* !WINDLL */
    else {
      ZIPERR(ZE_NONE, zipfile);
    }
  }
  d = (d && k == 0 && (zipbeg || zfiles != NULL)); /* d true if appending */

#if CRYPT
  /* Initialize the crc_32_tab pointer, when encryption was requested. */
  if (key != NULL) {
    crc_32_tab = get_crc_table();
#ifdef EBCDIC
    /* convert encryption key to ASCII (ISO variant for 8-bit ASCII chars) */
    strtoasc(key, key);
#endif /* EBCDIC */
  }
#endif /* CRYPT */

  /* Before we get carried away, make sure zip file is writeable. This
   * has the undesired side effect of leaving one empty junk file on a WORM,
   * so when the zipfile does not exist already and when -b is specified,
   * the writability check is made in replace().
   */
  if (strcmp(zipfile, "-"))
  {
    if (tempdir && zfiles == NULL && zipbeg == 0) {
      a = 0;
    } else {
      x = zfiles == NULL && zipbeg == 0 ? fopen(zipfile, FOPW) :
                                          fopen(zipfile, FOPM);
      /* Note: FOPW and FOPM expand to several parameters for VMS */
      if (x == NULL) {
        ZIPERR(ZE_CREAT, zipfile);
      }
      fclose(x);
      a = getfileattr(zipfile);
      if (zfiles == NULL && zipbeg == 0)
        destroy(zipfile);
    }
  }
  else
    a = 0;

  /* Throw away the garbage in front of the zip file for -J */
  if (junk_sfx) zipbeg = 0;

  /* Open zip file and temporary output file */
  diag("opening zip file and creating temporary zip file");
  x = NULL;
  tempzn = 0;
  if (strcmp(zipfile, "-") == 0)
  {
#ifdef MSDOS
    /* It is nonsense to emit the binary data stream of a zipfile to
     * the (text mode) console.  This case should already have been caught
     * in a call to zipstdout() far above.  Therefore, if the following
     * failsafe check detects a console attached to stdout, zip is stopped
     * with an "internal logic error"!  */
    if (isatty(fileno(stdout)))
      ZIPERR(ZE_LOGIC, "tried to write binary zipfile data to console!");
    /* Set stdout mode to binary for MSDOS systems */
#  ifdef __HIGHC__
    setmode(stdout, _BINARY);
#  else
    setmode(fileno(stdout), O_BINARY);
#  endif
    tempzf = y = fdopen(fileno(stdout), FOPW);
#else
    tempzf = y = stdout;
#endif
    /* tempzip must be malloced so a later free won't barf */
    tempzip = malloc(4);
    if (tempzip == NULL) {
      ZIPERR(ZE_MEM, "allocating temp filename");
    }
    strcpy(tempzip, "-");
  }
  else if (d) /* d true if just appending (-g) */
  {
    if ((y = fopen(zipfile, FOPM)) == NULL) {
      ZIPERR(ZE_NAME, zipfile);
    }
    tempzip = zipfile;
    tempzf = y;
    if (fseek(y, cenbeg, SEEK_SET)) {
      ZIPERR(ferror(y) ? ZE_READ : ZE_EOF, zipfile);
    }
    tempzn = cenbeg;
  }
  else
  {
    if ((zfiles != NULL || zipbeg) && (x = fopen(zipfile, FOPR_EX)) == NULL) {
      ZIPERR(ZE_NAME, zipfile);
    }
    if ((tempzip = tempname(zipfile)) == NULL) {
      ZIPERR(ZE_MEM, "allocating temp filename");
    }
    if ((tempzf = y = fopen(tempzip, FOPW_TMP)) == NULL) {
      ZIPERR(ZE_TEMP, tempzip);
    }
  }

#if (!defined(VMS) && !defined(CMS_MVS))
  /* Use large buffer to speed up stdio: */
#if (defined(_IOFBF) || !defined(BUFSIZ))
  zipbuf = (char *)malloc(ZBSZ);
#else
  zipbuf = (char *)malloc(BUFSIZ);
#endif
  if (zipbuf == NULL) {
    ZIPERR(ZE_MEM, tempzip);
  }
# ifdef _IOFBF
  setvbuf(y, zipbuf, _IOFBF, ZBSZ);
# else
  setbuf(y, zipbuf);
# endif /* _IOBUF */
#endif /* !VMS  && !CMS_MVS */

  if (strcmp(zipfile, "-") != 0 && !d)  /* this must go *after* set[v]buf */
  {
    if (zipbeg && (r = fcopy(x, y, zipbeg)) != ZE_OK) {
      ZIPERR(r, r == ZE_TEMP ? tempzip : zipfile);
    }
    tempzn = zipbeg;
  }

  o = 0;                                /* no ZE_OPEN errors yet */


  /* Process zip file, updating marked files */
#ifdef DEBUG
  if (zfiles != NULL)
    diag("going through old zip file");
#endif
  w = &zfiles;
  while ((z = *w) != NULL) {
    if (z->mark == 1)
    {
      /* if not deleting, zip it up */
      if (action != DELETE)
      {
        if (noisy)
        {
          if (action == FRESHEN)
             fprintf(mesg, "freshening: %s", z->zname);
          else
             fprintf(mesg, "updating: %s", z->zname);
          fflush(mesg);
        }
        if ((r = zipup(z, y)) != ZE_OK && r != ZE_OPEN && r != ZE_MISS)
        {
          if (noisy)
          {
#if (!defined(MACOS) && !defined(WINDLL))
            putc('\n', mesg);
            fflush(mesg);
#else
            fprintf(stdout, "\n");
#endif
          }
          sprintf(errbuf, "was zipping %s", z->name);
          ZIPERR(r, errbuf);
        }
        if (r == ZE_OPEN || r == ZE_MISS)
        {
          o = 1;
          if (noisy)
          {
#if (!defined(MACOS) && !defined(WINDLL))
            putc('\n', mesg);
            fflush(mesg);
#else
            fprintf(stdout, "\n");
#endif
          }
          if (r == ZE_OPEN) {
            if (bad_open_is_error) {
              sprintf(errbuf, "was zipping %s", z->name);
              ZIPERR(r, errbuf);
            } else {
              perror(z->zname);
              zipwarn("could not open for reading: ", z->zname);
            }
          } else {
            zipwarn("file and directory with the same name: ", z->zname);
          }
          zipwarn("will just copy entry over: ", z->zname);
          if ((r = zipcopy(z, x, y)) != ZE_OK)
          {
            sprintf(errbuf, "was copying %s", z->zname);
            ZIPERR(r, errbuf);
          }
          z->mark = 0;
        }
        w = &z->nxt;
      }
      else
      {
        if (noisy)
        {
          fprintf(mesg, "deleting: %s\n", z->zname);
          fflush(mesg);
        }
#ifdef WINDLL
        if (lpZipUserFunctions->ServiceApplication != NULL) {
          if ((*lpZipUserFunctions->ServiceApplication)(z->zname, 0))
            ZIPERR(ZE_ABORT, "User terminated operation");
        }
#endif
        v = z->nxt;                     /* delete entry from list */
        free((zvoid *)(z->iname));
        free((zvoid *)(z->zname));
        if (z->ext)
          free((zvoid *)(z->extra));
        if (z->cext && z->cextra != z->extra)
          free((zvoid *)(z->cextra));
        if (z->com)
          free((zvoid *)(z->comment));
        farfree((zvoid far *)z);
        *w = v;
        zcount--;
      }
    }
    else
    {
      /* copy the original entry verbatim */
      if (!d && (r = zipcopy(z, x, y)) != ZE_OK)
      {
        sprintf(errbuf, "was copying %s", z->zname);
        ZIPERR(r, errbuf);
      }
      w = &z->nxt;
    }
  }


  /* Process the edited found list, adding them to the zip file */
  diag("zipping up new entries, if any");
  Trace((stderr, "zip diagnostic: fcount=%u\n", (unsigned)fcount));
  for (f = found; f != NULL; f = fexpel(f))
  {
    /* add a new zfiles entry and set the name */
    if ((z = (struct zlist far *)farmalloc(sizeof(struct zlist))) == NULL) {
      ZIPERR(ZE_MEM, "was adding files to zip file");
    }
    z->nxt = NULL;
    z->name = f->name;
    f->name = NULL;
    z->iname = f->iname;
    f->iname = NULL;
    z->zname = f->zname;
    f->zname = NULL;
    z->ext = z->cext = z->com = 0;
    z->extra = z->cextra = NULL;
    z->mark = 1;
    z->dosflag = f->dosflag;
    /* zip it up */
    if (noisy)
    {
      fprintf(mesg, "  adding: %s", z->zname);
      fflush(mesg);
    }
    if ((r = zipup(z, y)) != ZE_OK  && r != ZE_OPEN && r != ZE_MISS)
    {
      if (noisy)
      {
#if (!defined(MACOS) && !defined(WINDLL))
        putc('\n', mesg);
        fflush(mesg);
#else
        fprintf(stdout, "\n");
#endif
      }
      sprintf(errbuf, "was zipping %s", z->zname);
      ZIPERR(r, errbuf);
    }
    if (r == ZE_OPEN || r == ZE_MISS)
    {
      o = 1;
      if (noisy)
      {
#if (!defined(MACOS) && !defined(WINDLL))
        putc('\n', mesg);
        fflush(mesg);
#else
        fprintf(stdout, "\n");
#endif
      }
      if (r == ZE_OPEN) {
        if (bad_open_is_error) {
          sprintf(errbuf, "was zipping %s", z->name);
          ZIPERR(r, errbuf);
        } else {
          perror("zip warning");
          zipwarn("could not open for reading: ", z->zname);
        }
      } else {
        zipwarn("file and directory with the same name: ", z->zname);
      }
      free((zvoid *)(z->name));
      free((zvoid *)(z->iname));
      free((zvoid *)(z->zname));
      farfree((zvoid far *)z);
    }
    else
    {
      *w = z;
      w = &z->nxt;
      zcount++;
    }
  }
  if (key != NULL)
  {
    free((zvoid *)key);
    key = NULL;
  }


  /* Get one line comment for each new entry */
#if defined(AMIGA) || defined(MACOS)
  if (comadd || filenotes)
  {
    if (comadd)
#else
  if (comadd)
  {
#endif
    {
      if (comment_stream == NULL) {
#ifndef RISCOS
        comment_stream = (FILE*)fdopen(fileno(stderr), "r");
#else
        comment_stream = stderr;
#endif
      }
      if ((e = malloc(MAXCOM + 1)) == NULL) {
        ZIPERR(ZE_MEM, "was reading comment lines");