unzip.cpp

这是CODEPROJECT上的zip压缩解压代码

      {
        s->mode = IBM_BAD;
        z->msg = (char*)"too many length or distance symbols";
        r = Z_DATA_ERROR;
        LEAVE
      }
      // end remove
      t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f);
      if ((s->sub.trees.blens = (uInt*)ZALLOC(z, t, sizeof(uInt))) == Z_NULL)
      {
        r = Z_MEM_ERROR;
        LEAVE
      }
      DUMPBITS(14)
      s->sub.trees.index = 0;
      LuTracev((stderr, "inflate:       table sizes ok\n"));
      s->mode = IBM_BTREE;
    case IBM_BTREE:
      while (s->sub.trees.index < 4 + (s->sub.trees.table >> 10))
      {
        NEEDBITS(3)
        s->sub.trees.blens[border[s->sub.trees.index++]] = (uInt)b & 7;
        DUMPBITS(3)
      }
      while (s->sub.trees.index < 19)
        s->sub.trees.blens[border[s->sub.trees.index++]] = 0;
      s->sub.trees.bb = 7;
      t = inflate_trees_bits(s->sub.trees.blens, &s->sub.trees.bb,
                             &s->sub.trees.tb, s->hufts, z);
      if (t != Z_OK)
      {
        r = t;
        if (r == Z_DATA_ERROR)
        {
          ZFREE(z, s->sub.trees.blens);
          s->mode = IBM_BAD;
        }
        LEAVE
      }
      s->sub.trees.index = 0;
      LuTracev((stderr, "inflate:       bits tree ok\n"));
      s->mode = IBM_DTREE;
    case IBM_DTREE:
      while (t = s->sub.trees.table,
             s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))
      {
        inflate_huft *h;
        uInt i, j, c;

        t = s->sub.trees.bb;
        NEEDBITS(t)
        h = s->sub.trees.tb + ((uInt)b & inflate_mask[t]);
        t = h->bits;
        c = h->base;
        if (c < 16)
        {
          DUMPBITS(t)
          s->sub.trees.blens[s->sub.trees.index++] = c;
        }
        else // c == 16..18 
        {
          i = c == 18 ? 7 : c - 14;
          j = c == 18 ? 11 : 3;
          NEEDBITS(t + i)
          DUMPBITS(t)
          j += (uInt)b & inflate_mask[i];
          DUMPBITS(i)
          i = s->sub.trees.index;
          t = s->sub.trees.table;
          if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) ||
              (c == 16 && i < 1))
          {
            ZFREE(z, s->sub.trees.blens);
            s->mode = IBM_BAD;
            z->msg = (char*)"invalid bit length repeat";
            r = Z_DATA_ERROR;
            LEAVE
          }
          c = c == 16 ? s->sub.trees.blens[i - 1] : 0;
          do {
            s->sub.trees.blens[i++] = c;
          } while (--j);
          s->sub.trees.index = i;
        }
      }
      s->sub.trees.tb = Z_NULL;
      {
        uInt bl, bd;
        inflate_huft *tl, *td;
        inflate_codes_statef *c;

        bl = 9;         // must be <= 9 for lookahead assumptions 
        bd = 6;         // must be <= 9 for lookahead assumptions
        t = s->sub.trees.table;
        t = inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f),
                                  s->sub.trees.blens, &bl, &bd, &tl, &td,
                                  s->hufts, z);
        if (t != Z_OK)
        {
          if (t == (uInt)Z_DATA_ERROR)
          {
            ZFREE(z, s->sub.trees.blens);
            s->mode = IBM_BAD;
          }
          r = t;
          LEAVE
        }
        LuTracev((stderr, "inflate:       trees ok\n"));
        if ((c = inflate_codes_new(bl, bd, tl, td, z)) == Z_NULL)
        {
          r = Z_MEM_ERROR;
          LEAVE
        }
        s->sub.decode.codes = c;
      }
      ZFREE(z, s->sub.trees.blens);
      s->mode = IBM_CODES;
    case IBM_CODES:
      UPDATE
      if ((r = inflate_codes(s, z, r)) != Z_STREAM_END)
        return inflate_flush(s, z, r);
      r = Z_OK;
      inflate_codes_free(s->sub.decode.codes, z);
      LOAD
      LuTracev((stderr, "inflate:       codes end, %lu total out\n",
              z->total_out + (q >= s->read ? q - s->read :
              (s->end - s->read) + (q - s->window))));
      if (!s->last)
      {
        s->mode = IBM_TYPE;
        break;
      }
      s->mode = IBM_DRY;
    case IBM_DRY:
      FLUSH
      if (s->read != s->write)
        LEAVE
      s->mode = IBM_DONE;
    case IBM_DONE:
      r = Z_STREAM_END;
      LEAVE
    case IBM_BAD:
      r = Z_DATA_ERROR;
      LEAVE
    default:
      r = Z_STREAM_ERROR;
      LEAVE
  }
}


int inflate_blocks_free(inflate_blocks_statef *s, z_streamp z)
{
  inflate_blocks_reset(s, z, Z_NULL);
  ZFREE(z, s->window);
  ZFREE(z, s->hufts);
  ZFREE(z, s);
  LuTracev((stderr, "inflate:   blocks freed\n"));
  return Z_OK;
}



// inftrees.c -- generate Huffman trees for efficient decoding
// Copyright (C) 1995-1998 Mark Adler
// For conditions of distribution and use, see copyright notice in zlib.h
//



extern const char inflate_copyright[] =
   " inflate 1.1.3 Copyright 1995-1998 Mark Adler ";
// If you use the zlib library in a product, an acknowledgment is welcome
// in the documentation of your product. If for some reason you cannot
// include such an acknowledgment, I would appreciate that you keep this
// copyright string in the executable of your product.



int huft_build (
    uInt *,            // code lengths in bits
    uInt,               // number of codes
    uInt,               // number of "simple" codes
    const uInt *,      // list of base values for non-simple codes
    const uInt *,      // list of extra bits for non-simple codes
    inflate_huft **,// result: starting table
    uInt *,            // maximum lookup bits (returns actual) 
    inflate_huft *,     // space for trees 
    uInt *,             // hufts used in space 
    uInt * );         // space for values 

// Tables for deflate from PKZIP's appnote.txt. 
const uInt cplens[31] = { // Copy lengths for literal codes 257..285
        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};
        // see note #13 above about 258
const uInt cplext[31] = { // Extra bits for literal codes 257..285
        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, 112, 112}; // 112==invalid
const uInt cpdist[30] = { // Copy offsets for distance codes 0..29
        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,
        8193, 12289, 16385, 24577};
const uInt cpdext[30] = { // Extra bits for distance codes 
        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};

//
//   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
//   is 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.
//


// If BMAX needs to be larger than 16, then h and x[] should be uLong. 
#define BMAX 15         // maximum bit length of any code

int huft_build(
uInt *b,               // code lengths in bits (all assumed <= BMAX)
uInt n,                 // number of codes (assumed <= 288)
uInt s,                 // number of simple-valued codes (0..s-1)
const uInt *d,         // list of base values for non-simple codes
const uInt *e,         // list of extra bits for non-simple codes
inflate_huft * *t,  // result: starting table
uInt *m,               // maximum lookup bits, returns actual
inflate_huft *hp,       // space for trees
uInt *hn,               // hufts used in space
uInt *v)               // working area: values in order of bit length
// Given a list of code lengths and a maximum table size, make a set of
// tables to decode that set of codes.  Return Z_OK on success, Z_BUF_ERROR
// if the given code set is incomplete (the tables are still built in this
// case), or Z_DATA_ERROR if the input is invalid.
{

  uInt a;                       // counter for codes of length k
  uInt c[BMAX+1];               // bit length count table
  uInt f;                       // i repeats in table every f entries 
  int g;                        // maximum code length 
  int h;                        // table level 
  register uInt i;              // counter, current code 
  register uInt j;              // counter
  register int k;               // number of bits in current code 
  int l;                        // bits per table (returned in m) 
  uInt mask;                    // (1 << w) - 1, to avoid cc -O bug on HP 
  register uInt *p;            // pointer into c[], b[], or v[]
  inflate_huft *q;              // points to current table 
  struct inflate_huft_s r;      // table entry for structure assignment 
  inflate_huft *u[BMAX];        // table stack 
  register int w;               // bits before this table == (l * h) 
  uInt x[BMAX+1];               // bit offsets, then code stack 
  uInt *xp;                    // pointer into x 
  int y;                        // number of dummy codes added 
  uInt z;                       // number of entries in current table 


  // Generate counts for each bit length 
  p = c;
#define C0 *p++ = 0;
#define C2 C0 C0 C0 C0
#define C4 C2 C2 C2 C2
  C4; p;                          // clear c[]--assume BMAX+1 is 16
  p = b;  i = n;
  do {
    c[*p++]++;                  // assume all entries <= BMAX 
  } while (--i);
  if (c[0] == n)                // null input--all zero length codes 
  {
    *t = (inflate_huft *)Z_NULL;
    *m = 0;
    return Z_OK;
  }


  // Find minimum and maximum length, bound *m by those 
  l = *m;
  for (j = 1; j <= BMAX; j++)
    if (c[j])
      break;
  k = j;                        // minimum code length 
  if ((uInt)l < j)
    l = j;
  for (i = BMAX; i; i--)
    if (c[i])
      break;
  g = i;                        // maximum code length 
  if ((uInt)l > i)
    l = i;
  *m = l;


  // Adjust last length count to fill out codes, if needed 
  for (y = 1 << j; j < i; j++, y <<= 1)
    if ((y -= c[j]) < 0)
      return Z_DATA_ERROR;
  if ((y -= c[i]) < 0)
    return Z_DATA_ERROR;
  c[i] += y;


  // Generate starting offsets into the value table for each length 
  x[1] = j = 0;
  p = c + 1;  xp = x + 2;
  while (--i) {                 // note that i == g from above 
    *xp++ = (j += *p++);
  }


  // Make a table of values in order of bit lengths 
  p = b;  i = 0;
  do {
    if ((j = *p++) != 0)
      v[x[j]++] = i;
  } while (++i < n);
  n = x[g];                     // set n to length of v 


  // Generate the Huffman codes and for each, make the table entries 
  x[0] = i = 0;                 // first Huffman code is zero 
  p = v;                        // grab values in bit order 
  h = -1;