inflate.c

turecrypt最新6.0版本的源码

  /* make local copies of globals */
  Trace((stderr, "\nstored block"));
  b = G.bb;                       /* initialize bit buffer */
  k = G.bk;
  w = G.wp;                       /* initialize window position */


  /* go to byte boundary */
  n = k & 7;
  DUMPBITS(n);


  /* get the length and its complement */
  NEEDBITS(16)
  n = ((unsigned)b & 0xffff);
  DUMPBITS(16)
  NEEDBITS(16)
  if (n != (unsigned)((~b) & 0xffff))
    return 1;                   /* error in compressed data */
  DUMPBITS(16)


  /* read and output the compressed data */
  while (n--)
  {
    NEEDBITS(8)
    redirSlide[w++] = (uch)b;
    if (w == wsize)
    {
      FLUSH(w);
      w = 0;
    }
    DUMPBITS(8)
  }


  /* restore the globals from the locals */
  G.wp = w;                       /* restore global window pointer */
  G.bb = b;                       /* restore global bit buffer */
  G.bk = k;
  return 0;
}


/* Globals for literal tables (built once) */
/* Moved to globals.h                      */
#if 0
struct huft *fixed_tl = (struct huft *)NULL;
struct huft *fixed_td;
int fixed_bl, fixed_bd;
#endif

static int inflate_fixed(__G)
     __GDEF
/* decompress an inflated type 1 (fixed Huffman codes) block.  We should
   either replace this with a custom decoder, or at least precompute the
   Huffman tables. */
{
  /* if first time, set up tables for fixed blocks */
  Trace((stderr, "\nliteral block"));
  if (G.fixed_tl == (struct huft *)NULL)
  {
    int i;                /* temporary variable */
    unsigned l[288];      /* length list for huft_build */

    /* literal table */
    for (i = 0; i < 144; i++)
      l[i] = 8;
    for (; i < 256; i++)
      l[i] = 9;
    for (; i < 280; i++)
      l[i] = 7;
    for (; i < 288; i++)          /* make a complete, but wrong code set */
      l[i] = 8;
    G.fixed_bl = 7;
    if ((i = huft_build(__G__ l, 288, 257, cplens, cplext,
                        &G.fixed_tl, &G.fixed_bl)) != 0)
    {
      G.fixed_tl = (struct huft *)NULL;
      return i;
    }

    /* distance table */
    for (i = 0; i < 30; i++)      /* make an incomplete code set */
      l[i] = 5;
    G.fixed_bd = 5;
    if ((i = huft_build(__G__ l, 30, 0, cpdist, cpdext,
                        &G.fixed_td, &G.fixed_bd)) > 1)
    {
      huft_free(G.fixed_tl);
      G.fixed_tl = (struct huft *)NULL;
      return i;
    }
  }

  /* decompress until an end-of-block code */
  return inflate_codes(__G__ G.fixed_tl, G.fixed_td,
                             G.fixed_bl, G.fixed_bd) != 0;
}



static int inflate_dynamic(__G)
  __GDEF
/* decompress an inflated type 2 (dynamic Huffman codes) block. */
{
  int i;                /* temporary variables */
  unsigned j;
  unsigned l;           /* last length */
  unsigned m;           /* mask for bit lengths table */
  unsigned n;           /* number of lengths to get */
  struct huft *tl;      /* literal/length code table */
  struct huft *td;      /* distance code table */
  int bl;               /* lookup bits for tl */
  int bd;               /* lookup bits for td */
  unsigned nb;          /* number of bit length codes */
  unsigned nl;          /* number of literal/length codes */
  unsigned nd;          /* number of distance codes */
#ifdef PKZIP_BUG_WORKAROUND
  unsigned ll[288+32]; /* literal/length and distance code lengths */
#else
  unsigned ll[286+30]; /* literal/length and distance code lengths */
#endif
  register ulg b;       /* bit buffer */
  register unsigned k;  /* number of bits in bit buffer */


  /* make local bit buffer */
  Trace((stderr, "\ndynamic block"));
  b = G.bb;
  k = G.bk;


  /* read in table lengths */
  NEEDBITS(5)
  nl = 257 + ((unsigned)b & 0x1f);      /* number of literal/length codes */
  DUMPBITS(5)
  NEEDBITS(5)
  nd = 1 + ((unsigned)b & 0x1f);        /* number of distance codes */
  DUMPBITS(5)
  NEEDBITS(4)
  nb = 4 + ((unsigned)b & 0xf);         /* number of bit length codes */
  DUMPBITS(4)
#ifdef PKZIP_BUG_WORKAROUND
  if (nl > 288 || nd > 32)
#else
  if (nl > 286 || nd > 30)
#endif
    return 1;                   /* bad lengths */


  /* read in bit-length-code lengths */
  for (j = 0; j < nb; j++)
  {
    NEEDBITS(3)
    ll[border[j]] = (unsigned)b & 7;
    DUMPBITS(3)
  }
  for (; j < 19; j++)
    ll[border[j]] = 0;


  /* build decoding table for trees--single level, 7 bit lookup */
  bl = 7;
  i = huft_build(__G__ ll, 19, 19, NULL, NULL, &tl, &bl);
  if (bl == 0)                        /* no bit lengths */
    i = 1;
  if (i)
  {
    if (i == 1)
      huft_free(tl);
    return i;                   /* incomplete code set */
  }


  /* read in literal and distance code lengths */
  n = nl + nd;
  m = mask_bits[bl];
  i = l = 0;
  while ((unsigned)i < n)
  {
    NEEDBITS((unsigned)bl)
    j = (td = tl + ((unsigned)b & m))->b;
    DUMPBITS(j)
    j = td->v.n;
    if (j < 16)                 /* length of code in bits (0..15) */
      ll[i++] = l = j;          /* save last length in l */
    else if (j == 16)           /* repeat last length 3 to 6 times */
    {
      NEEDBITS(2)
      j = 3 + ((unsigned)b & 3);
      DUMPBITS(2)
      if ((unsigned)i + j > n)
        return 1;
      while (j--)
        ll[i++] = l;
    }
    else if (j == 17)           /* 3 to 10 zero length codes */
    {
      NEEDBITS(3)
      j = 3 + ((unsigned)b & 7);
      DUMPBITS(3)
      if ((unsigned)i + j > n)
        return 1;
      while (j--)
        ll[i++] = 0;
      l = 0;
    }
    else                        /* j == 18: 11 to 138 zero length codes */
    {
      NEEDBITS(7)
      j = 11 + ((unsigned)b & 0x7f);
      DUMPBITS(7)
      if ((unsigned)i + j > n)
        return 1;
      while (j--)
        ll[i++] = 0;
      l = 0;
    }
  }


  /* free decoding table for trees */
  huft_free(tl);


  /* restore the global bit buffer */
  G.bb = b;
  G.bk = k;


  /* build the decoding tables for literal/length and distance codes */
  bl = lbits;
  i = huft_build(__G__ ll, nl, 257, cplens, cplext, &tl, &bl);
  if (bl == 0)                        /* no literals or lengths */
    i = 1;
  if (i)
  {
    if (i == 1) {
      //if (!uO.qflag)
        MESSAGE((uch *)"(incomplete l-tree)  ", 21L, 1);
      huft_free(tl);
    }
    return i;                   /* incomplete code set */
  }
  bd = dbits;
  i = huft_build(__G__ ll + nl, nd, 0, cpdist, cpdext, &td, &bd);
  if (bd == 0 && nl > 257)    /* lengths but no distances */
  {
    //if (!uO.qflag)
      MESSAGE((uch *)"(incomplete d-tree)  ", 21L, 1);
    huft_free(tl);
    return 1;
  }
  if (i == 1) {
#ifdef PKZIP_BUG_WORKAROUND
    i = 0;
#else
    //if (!uO.qflag)
      MESSAGE((uch *)"(incomplete d-tree)  ", 21L, 1);
    huft_free(td);
#endif
  }
  if (i)
  {
    huft_free(tl);
    return i;
  }


  /* decompress until an end-of-block code */
  if (inflate_codes(__G__ tl, td, bl, bd))
    return 1;


  /* free the decoding tables, return */
  huft_free(tl);
  huft_free(td);
  return 0;
}



static int inflate_block(__G__ e)
  __GDEF
  int *e;               /* last block flag */
/* decompress an inflated block */
{
  unsigned t;           /* block type */
  register ulg b;       /* bit buffer */
  register unsigned k;  /* number of bits in bit buffer */


  /* make local bit buffer */
  b = G.bb;
  k = G.bk;


  /* read in last block bit */
  NEEDBITS(1)
  *e = (int)b & 1;
  DUMPBITS(1)


  /* read in block type */
  NEEDBITS(2)
  t = (unsigned)b & 3;
  DUMPBITS(2)


  /* restore the global bit buffer */
  G.bb = b;
  G.bk = k;


  /* inflate that block type */
  if (t == 2)
    return inflate_dynamic(__G);
  if (t == 0)
    return inflate_stored(__G);
  if (t == 1)
    return inflate_fixed(__G);


  /* bad block type */