inflate.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.

        err = inflateInit2(&G.dstrm, -windowBits);

        if (err == Z_MEM_ERROR)
            return 3;
        else if (err != Z_OK)
            Trace((stderr, "oops!  (inflateInit2() err = %d)\n", err));
        G.inflInit = 1;
    }

#ifdef FUNZIP
    while (err != Z_STREAM_END) {
#else /* !FUNZIP */
    while (G.csize > 0) {
        Trace((stderr, "first loop:  G.csize = %ld\n", G.csize));
#endif /* ?FUNZIP */
        while (G.dstrm.avail_out > 0) {
            err = inflate(&G.dstrm, Z_PARTIAL_FLUSH);

            if (err == Z_DATA_ERROR) {
                retval = 2; goto uzinflate_cleanup_exit;
            } else if (err == Z_MEM_ERROR) {
                retval = 3; goto uzinflate_cleanup_exit;
            } else if (err != Z_OK && err != Z_STREAM_END)
                Trace((stderr, "oops!  (inflate(first loop) err = %d)\n", err));

#ifdef FUNZIP
            if (err == Z_STREAM_END)    /* "END-of-entry-condition" ? */
#else /* !FUNZIP */
            if (G.csize <= 0L)          /* "END-of-entry-condition" ? */
#endif /* ?FUNZIP */
                break;

            if (G.dstrm.avail_in == 0) {
                if (fillinbuf(__G) == 0) {
                    /* no "END-condition" yet, but no more data */
                    retval = 2; goto uzinflate_cleanup_exit;
                }

                G.dstrm.next_in = G.inptr;
                G.dstrm.avail_in = G.incnt;
            }
            Trace((stderr, "     avail_in = %u\n", G.dstrm.avail_in));
        }
        /* flush slide[] */
        if ((retval = FLUSH(wsize - G.dstrm.avail_out)) != 0)
            goto uzinflate_cleanup_exit;
        Trace((stderr, "inside loop:  flushing %ld bytes (ptr diff = %ld)\n",
          (long)(wsize - G.dstrm.avail_out),
          (long)(G.dstrm.next_out-(Bytef *)redirSlide)));
        G.dstrm.next_out = redirSlide;
        G.dstrm.avail_out = wsize;
    }

    /* no more input, so loop until we have all output */
    Trace((stderr, "beginning final loop:  err = %d\n", err));
    repeated_buf_err = FALSE;
    while (err != Z_STREAM_END) {
        err = inflate(&G.dstrm, Z_PARTIAL_FLUSH);
        if (err == Z_DATA_ERROR) {
            retval = 2; goto uzinflate_cleanup_exit;
        } else if (err == Z_MEM_ERROR) {
            retval = 3; goto uzinflate_cleanup_exit;
        } else if (err == Z_BUF_ERROR) {                /* DEBUG */
#ifdef FUNZIP
            Trace((stderr,
                   "zlib inflate() did not detect stream end\n"));
#else
            Trace((stderr,
                   "zlib inflate() did not detect stream end (%s, %s)\n",
                   G.zipfn, G.filename));
#endif
            if ((!repeated_buf_err) && (G.dstrm.avail_in == 0)) {
                /* when detecting this problem for the first time,
                   try to provide one fake byte beyond "EOF"... */
                G.dstrm.next_in = "";
                G.dstrm.avail_in = 1;
                repeated_buf_err = TRUE;
            } else
                break;
        } else if (err != Z_OK && err != Z_STREAM_END) {
            Trace((stderr, "oops!  (inflate(final loop) err = %d)\n", err));
            DESTROYGLOBALS();
            EXIT(PK_MEM3);
        }
        /* final flush of slide[] */
        if ((retval = FLUSH(wsize - G.dstrm.avail_out)) != 0)
            goto uzinflate_cleanup_exit;
        Trace((stderr, "final loop:  flushing %ld bytes (ptr diff = %ld)\n",
          (long)(wsize - G.dstrm.avail_out),
          (long)(G.dstrm.next_out-(Bytef *)redirSlide)));
        G.dstrm.next_out = redirSlide;
        G.dstrm.avail_out = wsize;
    }
    Trace((stderr, "total in = %lu, total out = %lu\n", G.dstrm.total_in,
      G.dstrm.total_out));

    G.inptr = (uch *)G.dstrm.next_in;
    G.incnt = (G.inbuf + INBUFSIZ) - G.inptr;  /* reset for other routines */

uzinflate_cleanup_exit:
    err = inflateReset(&G.dstrm);
    if (err != Z_OK)
        Trace((stderr, "oops!  (inflateReset() err = %d)\n", err));

    return retval;
}


/*---------------------------------------------------------------------------*/
#else /* !USE_ZLIB */


/* Function prototypes */
#ifndef OF
#  ifdef __STDC__
#    define OF(a) a
#  else
#    define OF(a) ()
#  endif
#endif /* !OF */
int inflate_codes OF((__GPRO__ struct huft *tl, struct huft *td,
                      unsigned bl, unsigned bd));
static int inflate_stored OF((__GPRO));
static int inflate_fixed OF((__GPRO));
static int inflate_dynamic OF((__GPRO));
static int inflate_block OF((__GPRO__ int *e));


/* The inflate algorithm uses a sliding 32K byte window on the uncompressed
   stream to find repeated byte strings.  This is implemented here as a
   circular buffer.  The index is updated simply by incrementing and then
   and'ing with 0x7fff (32K-1). */
/* It is left to other modules to supply the 32K area.  It is assumed
   to be usable as if it were declared "uch slide[32768];" or as just
   "uch *slide;" and then malloc'ed in the latter case.  The definition
   must be in unzip.h, included above. */


/* unsigned wp;  moved to globals.h */     /* current position in slide */

/* Tables for deflate from PKZIP's appnote.txt. */
/* - Order of the bit length code lengths */
static ZCONST unsigned border[] = {
        16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};

/* - Copy lengths for literal codes 257..285 */
#ifdef USE_DEFLATE64
static ZCONST ush cplens64[] = {
        3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
        35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 3, 0, 0};
        /* For Deflate64, the code 285 is defined differently. */
#else
#  define cplens32 cplens
#endif
static ZCONST ush cplens32[] = {
        3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
        35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
        /* note: see note #13 above about the 258 in this list. */
/* - Extra bits for literal codes 257..285 */
#ifdef USE_DEFLATE64
static ZCONST uch cplext64[] = {
        0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
        3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 16, INVALID_CODE, INVALID_CODE};
#else
#  define cplext32 cplext
#endif
static ZCONST uch cplext32[] = {
        0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
        3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, INVALID_CODE, INVALID_CODE};

/* - Copy offsets for distance codes 0..29 (0..31 for Deflate64) */
static ZCONST ush cpdist[] = {
        1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
        257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
#if (defined(USE_DEFLATE64) || defined(PKZIP_BUG_WORKAROUND))
        8193, 12289, 16385, 24577, 32769, 49153};
#else
        8193, 12289, 16385, 24577};
#endif

/* - Extra bits for distance codes 0..29 (0..31 for Deflate64) */
#ifdef USE_DEFLATE64
static ZCONST uch cpdext64[] = {
        0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
        7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
        12, 12, 13, 13, 14, 14};
#else
#  define cpdext32 cpdext
#endif
static ZCONST uch cpdext32[] = {
        0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
        7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
#ifdef PKZIP_BUG_WORKAROUND
        12, 12, 13, 13, INVALID_CODE, INVALID_CODE};
#else
        12, 12, 13, 13};
#endif

#ifdef PKZIP_BUG_WORKAROUND
#  define MAXLITLENS 288
#else
#  define MAXLITLENS 286
#endif
#if (defined(USE_DEFLATE64) || defined(PKZIP_BUG_WORKAROUND))
#  define MAXDISTS 32
#else
#  define MAXDISTS 30
#endif


/* moved to consts.h (included in unzip.c), resp. funzip.c */
#if 0
/* And'ing with mask_bits[n] masks the lower n bits */
ZCONST unsigned near mask_bits[17] = {
    0x0000,
    0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
    0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};
#endif /* 0 */


/* Macros for inflate() bit peeking and grabbing.
   The usage is:

        NEEDBITS(j)
        x = b & mask_bits[j];
        DUMPBITS(j)

   where NEEDBITS makes sure that b has at least j bits in it, and
   DUMPBITS removes the bits from b.  The macros use the variable k
   for the number of bits in b.  Normally, b and k are register
   variables for speed and are initialized at the beginning of a
   routine that uses these macros from a global bit buffer and count.

   In order to not ask for more bits than there are in the compressed
   stream, the Huffman tables are constructed to only ask for just
   enough bits to make up the end-of-block code (value 256).  Then no
   bytes need to be "returned" to the buffer at the end of the last
   block.  See the huft_build() routine.

   Actually, the precautions mentioned above are not sufficient to
   prevent fetches of bits beyound the end of the last block in every
   case. When the last code fetched before the end-of-block code was
   a very short distance code (shorter than "distance-prefetch-bits" -
   "end-of-block code bits"), this last distance code fetch already
   exausts the available data.  To prevent failure of extraction in this
   case, the "read beyond EOF" check delays the raise of the "invalid
   data" error until an actual overflow of "used data" is detected.
   This error condition is only fulfilled when the "number of available
   bits" counter k is found to be negative in the NEEDBITS() macro.

   An alternate fix for that problem adjusts the size of the distance code
   base table so that it does not exceed the length of the end-of-block code
   plus the minimum length of a distance code. This alternate fix can be
   enabled by defining the preprocessor symbol FIX_PAST_EOB_BY_TABLEADJUST.
 */

/* These have been moved to globals.h */
#if 0
ulg bb;                         /* bit buffer */
unsigned bk;                    /* bits in bit buffer */
#endif

#ifndef CHECK_EOF
#  define CHECK_EOF   /* default as of 5.13/5.2 */
#endif

#ifndef CHECK_EOF
#  define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE)<<k;k+=8;}}
#else
# ifdef FIX_PAST_EOB_BY_TABLEADJUST
#  define NEEDBITS(n) {while(k<(n)){int c=NEXTBYTE;\
    if(c==EOF){retval=1;goto cleanup_and_exit;}\
    b|=((ulg)c)<<k;k+=8;}}
# else
#  define NEEDBITS(n) {while((int)k<(int)(n)){int c=NEXTBYTE;\
    if(c==EOF){if((int)k>=0)break;retval=1;goto cleanup_and_exit;}\
    b|=((ulg)c)<<k;k+=8;}}
# endif
#endif

#define DUMPBITS(n) {b>>=(n);k-=(n);}


/*
   Huffman code decoding is performed using a multi-level table lookup.
   The fastest way to decode is to simply build a lookup table whose
   size is determined by the longest code.  However, the time it takes
   to build this table can also be a factor if the data being decoded
   are not very long.  The most common codes are necessarily the
   shortest codes, so those codes dominate the decoding time, and hence
   the speed.  The idea is you can have a shorter table that decodes the
   shorter, more probable codes, and then point to subsidiary tables for
   the longer codes.  The time it costs to decode the longer codes is
   then traded against the time it takes to make longer tables.

   This results of this trade are in the variables lbits and dbits
   below.  lbits is the number of bits the first level table for literal/
   length codes can decode in one step, and dbits is the same thing for
   the distance codes.  Subsequent tables are also less than or equal to
   those sizes.  These values may be adjusted either when all of the
   codes are shorter than that, in which case the longest code length in
   bits is used, or when the shortest code is *longer* than the requested
   table size, in which case the length of the shortest code in bits is
   used.

   There are two different values for the two tables, since they code a
   different number of possibilities each.  The literal/length table
   codes 286 possible values, or in a flat code, a little over eight
   bits.  The distance table codes 30 possible values, or a little less
   than five bits, flat.  The optimum values for speed end up being
   about one bit more than those, so lbits is 8+1 and dbits is 5+1.
   The optimum values may differ though from machine to machine, and
   possibly even between compilers.  Your mileage may vary.
 */


/* bits in base literal/length lookup table */
static ZCONST unsigned lbits = 9;
/* bits in base distance lookup table */
static ZCONST unsigned dbits = 6;


#ifndef ASM_INFLATECODES

int inflate_codes(__G__ tl, td, bl, bd)
     __GDEF
struct huft *tl, *td;   /* literal/length and distance decoder tables */
unsigned bl, bd;        /* number of bits decoded by tl[] and td[] */
/* inflate (decompress) the codes in a deflated (compressed) block.
   Return an error code or zero if it all goes ok. */
{
  register unsigned e;  /* table entry flag/number of extra bits */
  unsigned d;           /* index for copy */
  UINT_D64 n;           /* length for copy (deflate64: might be 64k+2) */
  UINT_D64 w;           /* current window position (deflate64: up to 64k) */
  struct huft *t;       /* pointer to table entry */
  unsigned ml, md;      /* masks for bl and bd bits */
  register ulg b;       /* bit buffer */
  register unsigned k;  /* number of bits in bit buffer */
  int retval = 0;       /* error code returned: initialized to "no error" */


  /* make local copies of globals */
  b = G.bb;                       /* initialize bit buffer */
  k = G.bk;
  w = G.wp;                       /* initialize window position */


  /* inflate the coded data */
  ml = mask_bits[bl];           /* precompute masks for speed */
  md = mask_bits[bd];
  while (1)                     /* do until end of block */
  {
    NEEDBITS(bl)
    t = tl + ((unsigned)b & ml);
    while (1) {
      DUMPBITS(t->b)

      if ((e = t->e) == 32)     /* then it's a literal */
      {
        redirSlide[w++] = (uch)t->v.n;
        if (w == wsize)
        {
          if ((retval = FLUSH(w)) != 0) goto cleanup_and_exit;
          w = 0;
        }
        break;
      }

      if (e < 31)               /* then it's a length */
      {
        /* get length of block to copy */
        NEEDBITS(e)
        n = t->v.n + ((unsigned)b & mask_bits[e]);
        DUMPBITS(e)

        /* decode distance of block to copy */
        NEEDBITS(bd)
        t = td + ((unsigned)b & md);
        while (1) {
          DUMPBITS(t->b)
          if ((e = t->e) < 32)
            break;
          if (IS_INVALID_CODE(e))
            return 1;
          e &= 31;
          NEEDBITS(e)