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.

          t = t->v.t + ((unsigned)b & mask_bits[e]);
        }
        NEEDBITS(e)
        d = (unsigned)w - t->v.n - ((unsigned)b & mask_bits[e]);
        DUMPBITS(e)

        /* do the copy */
        do {
#if (defined(DLL) && !defined(NO_SLIDE_REDIR))
          if (G.redirect_slide) {
            /* &= w/ wsize unnecessary & wrong if redirect */
            if ((UINT_D64)d >= wsize)
              return 1;         /* invalid compressed data */
            e = (unsigned)(wsize - (d > (unsigned)w ? (UINT_D64)d : w));
          }
          else
#endif
            e = (unsigned)(wsize -
                           ((d &= (unsigned)(wsize-1)) > (unsigned)w ?
                            (UINT_D64)d : w));
          if ((UINT_D64)e > n) e = (unsigned)n;
          n -= e;
#ifndef NOMEMCPY
          if ((unsigned)w - d >= e)
          /* (this test assumes unsigned comparison) */
          {
            memcpy(redirSlide + (unsigned)w, redirSlide + d, e);
            w += e;
            d += e;
          }
          else                  /* do it slowly to avoid memcpy() overlap */
#endif /* !NOMEMCPY */
            do {
              redirSlide[w++] = redirSlide[d++];
            } while (--e);
          if (w == wsize)
          {
            if ((retval = FLUSH(w)) != 0) goto cleanup_and_exit;
            w = 0;
          }
        } while (n);
        break;
      }

      if (e == 31)              /* it's the EOB signal */
      {
        /* sorry for this goto, but we have to exit two loops at once */
        goto cleanup_decode;
      }

      if (IS_INVALID_CODE(e))
        return 1;

      e &= 31;
      NEEDBITS(e)
      t = t->v.t + ((unsigned)b & mask_bits[e]);
    }
  }
cleanup_decode:

  /* restore the globals from the locals */
  G.wp = (unsigned)w;             /* restore global window pointer */
  G.bb = b;                       /* restore global bit buffer */
  G.bk = k;


cleanup_and_exit:
  /* done */
  return retval;
}

#endif /* ASM_INFLATECODES */



static int inflate_stored(__G)
     __GDEF
/* "decompress" an inflated type 0 (stored) block. */
{
  UINT_D64 w;           /* current window position (deflate64: up to 64k!) */
  unsigned n;           /* number of bytes in block */
  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 */
  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)
    {
      if ((retval = FLUSH(w)) != 0) goto cleanup_and_exit;
      w = 0;
    }
    DUMPBITS(8)
  }


  /* restore the globals from the locals */
  G.wp = (unsigned)w;             /* restore global window pointer */
  G.bb = b;                       /* restore global bit buffer */
  G.bk = k;

cleanup_and_exit:
  return retval;
}


/* 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;
#ifdef USE_DEFLATE64
    if ((i = huft_build(__G__ l, 288, 257, G.cplens, G.cplext,
                        &G.fixed_tl, &G.fixed_bl)) != 0)
#else
    if ((i = huft_build(__G__ l, 288, 257, cplens, cplext,
                        &G.fixed_tl, &G.fixed_bl)) != 0)
#endif
    {
      G.fixed_tl = (struct huft *)NULL;
      return i;
    }

    /* distance table */
    for (i = 0; i < MAXDISTS; i++)      /* make an incomplete code set */
      l[i] = 5;
    G.fixed_bd = 5;
#ifdef USE_DEFLATE64
    if ((i = huft_build(__G__ l, MAXDISTS, 0, cpdist, G.cpdext,
                        &G.fixed_td, &G.fixed_bd)) > 1)
#else
    if ((i = huft_build(__G__ l, MAXDISTS, 0, cpdist, cpdext,
                        &G.fixed_td, &G.fixed_bd)) > 1)
#endif
    {
      huft_free(G.fixed_tl);
      G.fixed_td = 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);
}



static int inflate_dynamic(__G)
  __GDEF
/* decompress an inflated type 2 (dynamic Huffman codes) block. */
{
  unsigned 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 */
  unsigned bl;          /* lookup bits for tl */
  unsigned 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 */
  unsigned ll[MAXLITLENS+MAXDISTS]; /* lit./length and distance code lengths */
  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 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)
  if (nl > MAXLITLENS || nd > MAXDISTS)
    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;
  retval = huft_build(__G__ ll, 19, 19, NULL, NULL, &tl, &bl);
  if (bl == 0)                  /* no bit lengths */
    retval = 1;
  if (retval)
  {
    if (retval == 1)
      huft_free(tl);
    return retval;              /* incomplete code set */
  }


  /* read in literal and distance code lengths */
  n = nl + nd;
  m = mask_bits[bl];
  i = l = 0;
  while (i < n)
  {
    NEEDBITS(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;
#ifdef USE_DEFLATE64
  retval = huft_build(__G__ ll, nl, 257, G.cplens, G.cplext, &tl, &bl);
#else
  retval = huft_build(__G__ ll, nl, 257, cplens, cplext, &tl, &bl);
#endif
  if (bl == 0)                  /* no literals or lengths */
    retval = 1;
  if (retval)
  {
    if (retval == 1) {
      if (!uO.qflag)
        MESSAGE((uch *)"(incomplete l-tree)  ", 21L, 1);
      huft_free(tl);
    }
    return retval;              /* incomplete code set */
  }
#ifdef FIX_PAST_EOB_BY_TABLEADJUST
  /* Adjust the requested distance base table size so that a distance code
     fetch never tries to get bits behind an immediatly following end-of-block
     code. */
  bd = (dbits <= bl+1 ? dbits : bl+1);
#else
  bd = dbits;
#endif
#ifdef USE_DEFLATE64
  retval = huft_build(__G__ ll + nl, nd, 0, cpdist, G.cpdext, &td, &bd);
#else
  retval = huft_build(__G__ ll + nl, nd, 0, cpdist, cpdext, &td, &bd);
#endif
#ifdef PKZIP_BUG_WORKAROUND
  if (retval == 1)
    retval = 0;
#endif
  if (bd == 0 && nl > 257)    /* lengths but no distances */
    retval = 1;
  if (retval)
  {
    if (retval == 1) {
      if (!uO.qflag)
        MESSAGE((uch *)"(incomplete d-tree)  ", 21L, 1);
      huft_free(td);
    }
    huft_free(tl);
    return retval;
  }

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

cleanup_and_exit:
  /* free the decoding tables, return */
  huft_free(tl);
  huft_free(td);
  return retval;
}



static int inflate_block(__G__ e)
  __GDEF
  int *e;               /* last block flag */
/* decompress an inflated block */
{
  unsigned t;           /* block type */