explode.c

完整的解压zip文件的源码。包含密码功能

      /* do the copy */
      s -= n;
      do {
#if (defined(DLL) && !defined(NO_SLIDE_REDIR))
        if (G.redirect_slide) {
          /* &= w/ wsize not needed and wrong if redirect */
          if (d >= wsize)
            return 1;
          n -= (e = (e = wsize - (d > w ? d : w)) > n ? n : e);
        } else
#endif
        n -= (e = (e = wsize - ((d &= wsize-1) > w ? d : w)) > n ? n : e);
        if (u && w <= d)
        {
          memzero(redirSlide + w, e);
          w += e;
          d += e;
        }
        else
#ifndef NOMEMCPY
          if (w - d >= e)       /* (this test assumes unsigned comparison) */
          {
            memcpy(redirSlide + w, redirSlide + d, e);
            w += e;
            d += e;
          }
          else                  /* do it slow to avoid memcpy() overlap */
#endif /* !NOMEMCPY */
            do {
              redirSlide[w++] = redirSlide[d++];
            } while (--e);
        if (w == wsize)
        {
          flush(__G__ redirSlide, (ulg)w, 0);
          w = u = 0;
        }
      } while (n);
    }
  }

  /* flush out redirSlide */
  flush(__G__ redirSlide, (ulg)w, 0);
  if (G.csize + G.incnt + (k >> 3))   /* should have read csize bytes, but */
  {                        /* sometimes read one too many:  k>>3 compensates */
    G.used_csize = G.lrec.csize - G.csize - G.incnt - (k >> 3);
    return 5;
  }
  return 0;
}



static int explode_lit4(__G__ tb, tl, td, bb, bl, bd)
     __GDEF
struct huft *tb, *tl, *td;      /* literal, length, and distance tables */
int bb, bl, bd;                 /* number of bits decoded by those */
/* Decompress the imploded data using coded literals and a 4K sliding
   window. */
{
  long s;               /* bytes to decompress */
  register unsigned e;  /* table entry flag/number of extra bits */
  unsigned n, d;        /* length and index for copy */
  unsigned w;           /* current window position */
  struct huft *t;       /* pointer to table entry */
  unsigned mb, ml, md;  /* masks for bb, bl, and bd bits */
  register ulg b;       /* bit buffer */
  register unsigned k;  /* number of bits in bit buffer */
  unsigned u;           /* true if unflushed */


  /* explode the coded data */
  b = k = w = 0;                /* initialize bit buffer, window */
  u = 1;                        /* buffer unflushed */
  mb = mask_bits[bb];           /* precompute masks for speed */
  ml = mask_bits[bl];
  md = mask_bits[bd];
  s = G.ucsize;
  while (s > 0)                 /* do until ucsize bytes uncompressed */
  {
    NEEDBITS(1)
    if (b & 1)                  /* then literal--decode it */
    {
      DUMPBITS(1)
      s--;
      NEEDBITS((unsigned)bb)    /* get coded literal */
      if ((e = (t = tb + ((~(unsigned)b) & mb))->e) > 16)
        do {
          if (e == 99)
            return 1;
          DUMPBITS(t->b)
          e -= 16;
          NEEDBITS(e)
        } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16);
      DUMPBITS(t->b)
      redirSlide[w++] = (uch)t->v.n;
      if (w == wsize)
      {
        flush(__G__ redirSlide, (ulg)w, 0);
        w = u = 0;
      }
    }
    else                        /* else distance/length */
    {
      DUMPBITS(1)
      NEEDBITS(6)               /* get distance low bits */
      d = (unsigned)b & 0x3f;
      DUMPBITS(6)
      NEEDBITS((unsigned)bd)    /* get coded distance high bits */
      if ((e = (t = td + ((~(unsigned)b) & md))->e) > 16)
        do {
          if (e == 99)
            return 1;
          DUMPBITS(t->b)
          e -= 16;
          NEEDBITS(e)
        } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16);
      DUMPBITS(t->b)
      d = w - d - t->v.n;       /* construct offset */
      NEEDBITS((unsigned)bl)    /* get coded length */
      if ((e = (t = tl + ((~(unsigned)b) & ml))->e) > 16)
        do {
          if (e == 99)
            return 1;
          DUMPBITS(t->b)
          e -= 16;
          NEEDBITS(e)
        } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16);
      DUMPBITS(t->b)
      n = t->v.n;
      if (e)                    /* get length extra bits */
      {
        NEEDBITS(8)
        n += (unsigned)b & 0xff;
        DUMPBITS(8)
      }

      /* do the copy */
      s -= n;
      do {
#if (defined(DLL) && !defined(NO_SLIDE_REDIR))
        if (G.redirect_slide) {
          /* &= w/ wsize not needed and wrong if redirect */
          if (d >= wsize)
            return 1;
          n -= (e = (e = wsize - (d > w ? d : w)) > n ? n : e);
        } else
#endif
        n -= (e = (e = wsize - ((d &= wsize-1) > w ? d : w)) > n ? n : e);
        if (u && w <= d)
        {
          memzero(redirSlide + w, e);
          w += e;
          d += e;
        }
        else
#ifndef NOMEMCPY
          if (w - d >= e)       /* (this test assumes unsigned comparison) */
          {
            memcpy(redirSlide + w, redirSlide + d, e);
            w += e;
            d += e;
          }
          else                  /* do it slow to avoid memcpy() overlap */
#endif /* !NOMEMCPY */
            do {
              redirSlide[w++] = redirSlide[d++];
            } while (--e);
        if (w == wsize)
        {
          flush(__G__ redirSlide, (ulg)w, 0);
          w = u = 0;
        }
      } while (n);
    }
  }

  /* flush out redirSlide */
  flush(__G__ redirSlide, (ulg)w, 0);
  if (G.csize + G.incnt + (k >> 3))   /* should have read csize bytes, but */
  {                        /* sometimes read one too many:  k>>3 compensates */
    G.used_csize = G.lrec.csize - G.csize - G.incnt - (k >> 3);
    return 5;
  }
  return 0;
}



static int explode_nolit8(__G__ tl, td, bl, bd)
     __GDEF
struct huft *tl, *td;   /* length and distance decoder tables */
int bl, bd;             /* number of bits decoded by tl[] and td[] */
/* Decompress the imploded data using uncoded literals and an 8K sliding
   window. */
{
  long s;               /* bytes to decompress */
  register unsigned e;  /* table entry flag/number of extra bits */
  unsigned n, d;        /* length and index for copy */
  unsigned w;           /* current window position */
  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 */
  unsigned u;           /* true if unflushed */


  /* explode the coded data */
  b = k = w = 0;                /* initialize bit buffer, window */
  u = 1;                        /* buffer unflushed */
  ml = mask_bits[bl];           /* precompute masks for speed */
  md = mask_bits[bd];
  s = G.ucsize;
  while (s > 0)                 /* do until ucsize bytes uncompressed */
  {
    NEEDBITS(1)
    if (b & 1)                  /* then literal--get eight bits */
    {
      DUMPBITS(1)
      s--;
      NEEDBITS(8)
      redirSlide[w++] = (uch)b;
      if (w == wsize)
      {
        flush(__G__ redirSlide, (ulg)w, 0);
        w = u = 0;
      }
      DUMPBITS(8)
    }
    else                        /* else distance/length */
    {
      DUMPBITS(1)
      NEEDBITS(7)               /* get distance low bits */
      d = (unsigned)b & 0x7f;
      DUMPBITS(7)
      NEEDBITS((unsigned)bd)    /* get coded distance high bits */
      if ((e = (t = td + ((~(unsigned)b) & md))->e) > 16)
        do {
          if (e == 99)
            return 1;
          DUMPBITS(t->b)
          e -= 16;
          NEEDBITS(e)
        } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16);
      DUMPBITS(t->b)
      d = w - d - t->v.n;       /* construct offset */
      NEEDBITS((unsigned)bl)    /* get coded length */
      if ((e = (t = tl + ((~(unsigned)b) & ml))->e) > 16)
        do {
          if (e == 99)
            return 1;
          DUMPBITS(t->b)
          e -= 16;
          NEEDBITS(e)
        } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16);
      DUMPBITS(t->b)
      n = t->v.n;
      if (e)                    /* get length extra bits */
      {
        NEEDBITS(8)
        n += (unsigned)b & 0xff;
        DUMPBITS(8)
      }

      /* do the copy */
      s -= n;
      do {
#if (defined(DLL) && !defined(NO_SLIDE_REDIR))
        if (G.redirect_slide) {
          /* &= w/ wsize not needed and wrong if redirect */
          if (d >= wsize)
            return 1;
          n -= (e = (e = wsize - (d > w ? d : w)) > n ? n : e);
        } else
#endif
        n -= (e = (e = wsize - ((d &= wsize-1) > w ? d : w)) > n ? n : e);
        if (u && w <= d)
        {
          memzero(redirSlide + w, e);
          w += e;
          d += e;
        }
        else
#ifndef NOMEMCPY
          if (w - d >= e)       /* (this test assumes unsigned comparison) */
          {
            memcpy(redirSlide + w, redirSlide + d, e);
            w += e;
            d += e;
          }
          else                  /* do it slow to avoid memcpy() overlap */
#endif /* !NOMEMCPY */