funzip.c

压缩解压,是unzip540的升级,这个外国网站摘来的源码,是evb编写.

int flush(w)    /* used by inflate.c (FLUSH macro) */
ulg w;          /* number of bytes to flush */
{
  G.crc32val = crc32(G.crc32val, slide, (extent)w);
  if (fwrite((char *)slide,1,(extent)w,out) != (extent)w && !PIPE_ERROR)
    err(9, "out of space on stdout");
  outsiz += w;
  return 0;
}

#endif /* ?(USE_DEFLATE64 && __16BIT__) */


int main(argc, argv)
int argc;
char **argv;
/* Given a zipfile on stdin, decompress the first entry to stdout. */
{
  ush n;
  uch h[LOCHDR];                /* first local header (GZPHDR < LOCHDR) */
  int g = 0;                    /* true if gzip format */
  unsigned method = 0;          /* initialized here to shut up gcc warning */
#if CRYPT
  char *s = " [-password]";
  char *p;                      /* password */
#else /* !CRYPT */
  char *s = "";
#endif /* ?CRYPT */
  CONSTRUCTGLOBALS();

  /* skip executable name */
  argc--;
  argv++;

#if CRYPT
  /* get the command line password, if any */
  p = (char *)NULL;
  if (argc && **argv == '-')
  {
    argc--;
    p = 1 + *argv++;
  }
#endif /* CRYPT */

#ifdef MALLOC_WORK
  /* The following expression is a cooked-down simplyfication of the
     calculation for the work area size of UnZip (see unzip.c).  For
     fUnZip, the work area does not need to match the granularity
     of the complex unshrink structures, because it only supports
     inflation.  But, like in UnZip, the zcalloc() wrapper function
     is needed for the allocation, to support the 64kByte buffer on
     16-bit systems.
   */
# define UZ_SLIDE_CHUNK (sizeof(shrint)+sizeof(uch)+sizeof(uch))
# define UZ_NUMOF_CHUNKS (unsigned)( (WSIZE+UZ_SLIDE_CHUNK-1)/UZ_SLIDE_CHUNK )
  G.area.Slide = (uch *)zcalloc(UZ_NUMOF_CHUNKS, UZ_SLIDE_CHUNK);
# undef UZ_SLIDE_CHUNK
# undef UZ_NUMOF_CHUNKS
#endif

  /* if no file argument and stdin not redirected, give the user help */
  if (argc == 0 && isatty(0))
  {
    Info(slide, 1, ((char *)slide, "fUnZip (filter UnZip), version %s\n",
      VERSION));
    Info(slide, 1, ((char *)slide, "usage: ... | funzip%s | ...\n", s));
    Info(slide, 1, ((char *)slide, "       ... | funzip%s > outfile\n", s));
    Info(slide, 1, ((char *)slide, "       funzip%s infile.zip > outfile\n",s));
    Info(slide, 1, ((char *)slide, "       funzip%s infile.gz > outfile\n", s));
    Info(slide, 1, ((char *)slide, "Extracts to stdout the gzip file or first\
 zip entry of stdin or the given file.\n"));
    DESTROYGLOBALS();
    EXIT(3);
  }

  /* prepare to be a binary filter */
  if (argc)
  {
    if ((G.in = fopen(*argv, FOPR)) == (FILE *)NULL)
      err(2, "cannot find input file");
  }
  else
  {
#ifdef DOS_FLX_NLM_OS2_W32
#if (defined(__HIGHC__) && !defined(FLEXOS))
    setmode(stdin, _BINARY);
#else
    setmode(0, O_BINARY);  /* some buggy C libraries require BOTH setmode() */
#endif                     /*  call AND the fdopen() in binary mode :-( */
#endif /* DOS_FLX_NLM_OS2_W32 */

#ifdef RISCOS
    G.in = stdin;
#else
    if ((G.in = fdopen(0, FOPR)) == (FILE *)NULL)
      err(2, "cannot find stdin");
#endif
  }

#ifdef DOS_FLX_H68_NLM_OS2_W32
#if (defined(__HIGHC__) && !defined(FLEXOS))
  setmode(stdout, _BINARY);
#else
  setmode(1, O_BINARY);
#endif
#endif /* DOS_FLX_H68_NLM_OS2_W32 */

#ifdef RISCOS
  out = stdout;
#else
  if ((out = fdopen(1, FOPW)) == (FILE *)NULL)
    err(2, "cannot write to stdout");
#endif

  /* read local header, check validity, and skip name and extra fields */
  n = getc(G.in);  n |= getc(G.in) << 8;
  if (n == ZIPMAG)
  {
    if (fread((char *)h, 1, LOCHDR, G.in) != LOCHDR || SH(h) != LOCREM)
      err(3, "invalid zipfile");
    switch (method = SH(h + LOCHOW)) {
      case STORED:
      case DEFLATED:
#ifdef USE_DEFLATE64
      case ENHDEFLATED:
#endif
        break;
      default:
        err(3, "first entry not deflated or stored--cannot unpack");
        break;
    }
    for (n = SH(h + LOCFIL); n--; ) g = getc(G.in);
    for (n = SH(h + LOCEXT); n--; ) g = getc(G.in);
    g = 0;
    encrypted = h[LOCFLG] & CRPFLG;
  }
  else if (n == GZPMAG)
  {
    if (fread((char *)h, 1, GZPHDR, G.in) != GZPHDR)
      err(3, "invalid gzip file");
    if ((method = h[GZPHOW]) != DEFLATED && method != ENHDEFLATED)
      err(3, "gzip file not deflated");
    if (h[GZPFLG] & GZPMUL)
      err(3, "cannot handle multi-part gzip files");
    if (h[GZPFLG] & GZPISX)
    {
      n = getc(G.in);  n |= getc(G.in) << 8;
      while (n--) g = getc(G.in);
    }
    if (h[GZPFLG] & GZPISF)
      while ((g = getc(G.in)) != 0 && g != EOF) ;
    if (h[GZPFLG] & GZPISC)
      while ((g = getc(G.in)) != 0 && g != EOF) ;
    g = 1;
    encrypted = h[GZPFLG] & GZPISE;
  }
  else
    err(3, "input not a zip or gzip file");

  /* if entry encrypted, decrypt and validate encryption header */
  if (encrypted)
#if CRYPT
    {
      ush i, e;

      if (p == (char *)NULL) {
        if ((p = (char *)malloc(IZ_PWLEN+1)) == (char *)NULL)
          err(1, "out of memory");
        else if ((p = getp("Enter password: ", p, IZ_PWLEN+1)) == (char *)NULL)
          err(1, "no tty to prompt for password");
      }
#if (defined(USE_ZLIB) && !defined(USE_OWN_CRCTAB))
      /* initialize crc_32_tab pointer for decryption */
      CRC_32_TAB = (ZCONST ulg Far *)get_crc_table();
#endif
      init_keys(p);
      for (i = 0; i < RAND_HEAD_LEN; i++)
        e = NEXTBYTE;
      if (e != (ush)(h[LOCFLG] & EXTFLG ? h[LOCTIM + 1] : h[LOCCRC + 3]))
        err(3, "incorrect password for first entry");
    }
#else /* !CRYPT */
    err(3, "cannot decrypt entry (need to recompile with full crypt.c)");
#endif /* ?CRYPT */

  /* prepare output buffer and crc */
  G.outptr = slide;
  G.outcnt = 0L;
  outsiz = 0L;
  G.crc32val = CRCVAL_INITIAL;

  /* decompress */
  if (g || h[LOCHOW])
  {                             /* deflated entry */
    int r;

#ifdef USE_ZLIB
    /* need to allocate and prepare input buffer */
    if ((G.inbuf = (uch *)malloc(INBUFSIZ)) == (uch *)NULL)
       err(1, "out of memory");
#endif /* USE_ZLIB */
    if ((r = UZinflate(__G__ (method == ENHDEFLATED))) != 0) {
      if (r == 3)
        err(1, "out of memory");
      else
        err(4, "invalid compressed data--format violated");
    }
    inflate_free(__G);
  }
  else
  {                             /* stored entry */
    register ulg n;

    n = LG(h + LOCLEN);
#if CRYPT
    if (n != LG(h + LOCSIZ) - (encrypted ? RAND_HEAD_LEN : 0)) {
#else
    if (n != LG(h + LOCSIZ)) {
#endif
      Info(slide, 1, ((char *)slide, "len %ld, siz %ld\n", n, LG(h + LOCSIZ)));
      err(4, "invalid compressed data--length mismatch");
    }
    while (n--) {
      ush c = getc(G.in);
#if CRYPT
      if (encrypted)
        zdecode(c);
#endif
      *G.outptr++ = (uch)c;
#if (defined(USE_DEFLATE64) && defined(__16BIT__))
      if (++G.outcnt == (WSIZE>>1))     /* do FlushOutput() */
#else
      if (++G.outcnt == WSIZE)    /* do FlushOutput() */
#endif
      {
        G.crc32val = crc32(G.crc32val, slide, (extent)G.outcnt);
        if (fwrite((char *)slide, 1,(extent)G.outcnt,out) != (extent)G.outcnt
            && !PIPE_ERROR)
          err(9, "out of space on stdout");
        outsiz += G.outcnt;
        G.outptr = slide;
        G.outcnt = 0L;
      }
    }
  }
  if (G.outcnt)   /* flush one last time; no need to reset G.outptr/outcnt */
  {
    G.crc32val = crc32(G.crc32val, slide, (extent)G.outcnt);
    if (fwrite((char *)slide, 1,(extent)G.outcnt,out) != (extent)G.outcnt
        && !PIPE_ERROR)
      err(9, "out of space on stdout");
    outsiz += G.outcnt;
  }
  fflush(out);

  /* if extended header, get it */
  if (g)
  {
    if (fread((char *)h + LOCCRC, 1, 8, G.in) != 8)
      err(3, "gzip file ended prematurely");
  }
  else
    if ((h[LOCFLG] & EXTFLG) &&
        fread((char *)h + LOCCRC - 4, 1, EXTHDR, G.in) != EXTHDR)
      err(3, "zipfile ended prematurely");

  /* validate decompression */
  if (LG(h + LOCCRC) != G.crc32val)
    err(4, "invalid compressed data--crc error");
  if (LG((g ? (h + LOCSIZ) : (h + LOCLEN))) != outsiz)
    err(4, "invalid compressed data--length error");

  /* check if there are more entries */
  if (!g && fread((char *)h, 1, 4, G.in) == 4 && LG(h) == LOCSIG)
    Info(slide, 1, ((char *)slide,
      "funzip warning: zipfile has more than one entry--rest ignored\n"));

  DESTROYGLOBALS();
  RETURN (0);
}