Updated zlib, adding hashing functions, and introducing first bits of a new sliding window generic algorithm.

1 files changed, 296 insertions, 422 deletions

diff --git a/lib/zlib/src/inftrees.c b/lib/zlib/src/inftrees.c
index 4c32ca3..8a896b2 100644
--- a/lib/zlib/src/inftrees.c
+++ b/lib/zlib/src/inftrees.c
@@ -1,454 +1,328 @@
 /* inftrees.c -- generate Huffman trees for efficient decoding
- * Copyright (C) 1995-2002 Mark Adler
- * For conditions of distribution and use, see copyright notice in zlib.h 
+ * Copyright (C) 1995-2004 Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
 #include "zutil.h"
 #include "inftrees.h"
 
-#if !defined(BUILDFIXED) && !defined(STDC)
-#  define BUILDFIXED   /* non ANSI compilers may not accept inffixed.h */
-#endif
+#define MAXBITS 15
 
 const char inflate_copyright[] =
-   " inflate 1.1.4 Copyright 1995-2002 Mark Adler ";
+   " inflate 1.2.2 Copyright 1995-2004 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.
  */
-struct internal_state  {int dummy;}; /* for buggy compilers */
-
-/* simplify the use of the inflate_huft type with some defines */
-#define exop word.what.Exop
-#define bits word.what.Bits
-
-
-local int huft_build OF((
-    uIntf *,            /* code lengths in bits */
-    uInt,               /* number of codes */
-    uInt,               /* number of "simple" codes */
-    const uIntf *,      /* list of base values for non-simple codes */
-    const uIntf *,      /* list of extra bits for non-simple codes */
-    inflate_huft * FAR*,/* result: starting table */
-    uIntf *,            /* maximum lookup bits (returns actual) */
-    inflate_huft *,     /* space for trees */
-    uInt *,             /* hufts used in space */
-    uIntf * ));         /* space for values */
-
-/* Tables for deflate from PKZIP's appnote.txt. */
-local 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 */
-local 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 */
-local 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};
-local 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.
+   Build a set of tables to decode the provided canonical Huffman code.
+   The code lengths are lens[0..codes-1].  The result starts at *table,
+   whose indices are 0..2^bits-1.  work is a writable array of at least
+   lens shorts, which is used as a work area.  type is the type of code
+   to be generated, CODES, LENS, or DISTS.  On return, zero is success,
+   -1 is an invalid code, and +1 means that ENOUGH isn't enough.  table
+   on return points to the next available entry's address.  bits is the
+   requested root table index bits, and on return it is the actual root
+   table index bits.  It will differ if the request is greater than the
+   longest code or if it is less than the shortest code.
  */
-
-
-/* If BMAX needs to be larger than 16, then h and x[] should be uLong. */
-#define BMAX 15         /* maximum bit length of any code */
-
-local int huft_build(b, n, s, d, e, t, m, hp, hn, v)
-uIntf *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 uIntf *d;         /* list of base values for non-simple codes */
-const uIntf *e;         /* list of extra bits for non-simple codes */
-inflate_huft * FAR *t;  /* result: starting table */
-uIntf *m;               /* maximum lookup bits, returns actual */
-inflate_huft *hp;       /* space for trees */
-uInt *hn;               /* hufts used in space */
-uIntf *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. */
+int inflate_table(type, lens, codes, table, bits, work)
+codetype type;
+unsigned short FAR *lens;
+unsigned codes;
+code FAR * FAR *table;
+unsigned FAR *bits;
+unsigned short FAR *work;
 {
+    unsigned len;               /* a code's length in bits */
+    unsigned sym;               /* index of code symbols */
+    unsigned min, max;          /* minimum and maximum code lengths */
+    unsigned root;              /* number of index bits for root table */
+    unsigned curr;              /* number of index bits for current table */
+    unsigned drop;              /* code bits to drop for sub-table */
+    int left;                   /* number of prefix codes available */
+    unsigned used;              /* code entries in table used */
+    unsigned huff;              /* Huffman code */
+    unsigned incr;              /* for incrementing code, index */
+    unsigned fill;              /* index for replicating entries */
+    unsigned low;               /* low bits for current root entry */
+    unsigned mask;              /* mask for low root bits */
+    code this;                  /* table entry for duplication */
+    code FAR *next;             /* next available space in table */
+    const unsigned short FAR *base;     /* base value table to use */
+    const unsigned short FAR *extra;    /* extra bits table to use */
+    int end;                    /* use base and extra for symbol > end */
+    unsigned short count[MAXBITS+1];    /* number of codes of each length */
+    unsigned short offs[MAXBITS+1];     /* offsets in table for each length */
+    static const unsigned short lbase[31] = { /* Length codes 257..285 base */
+        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};
+    static const unsigned short lext[31] = { /* Length codes 257..285 extra */
+        16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18,
+        19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 199, 198};
+    static const unsigned short dbase[32] = { /* Distance codes 0..29 base */
+        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, 0, 0};
+    static const unsigned short dext[32] = { /* Distance codes 0..29 extra */
+        16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22,
+        23, 23, 24, 24, 25, 25, 26, 26, 27, 27,
+        28, 28, 29, 29, 64, 64};
+
+    /*
+       Process a set of code lengths to create a canonical Huffman code.  The
+       code lengths are lens[0..codes-1].  Each length corresponds to the
+       symbols 0..codes-1.  The Huffman code is generated by first sorting the
+       symbols by length from short to long, and retaining the symbol order
+       for codes with equal lengths.  Then the code starts with all zero bits
+       for the first code of the shortest length, and the codes are integer
+       increments for the same length, and zeros are appended as the length
+       increases.  For the deflate format, these bits are stored backwards
+       from their more natural integer increment ordering, and so when the
+       decoding tables are built in the large loop below, the integer codes
+       are incremented backwards.
+
+       This routine assumes, but does not check, that all of the entries in
+       lens[] are in the range 0..MAXBITS.  The caller must assure this.
+       1..MAXBITS is interpreted as that code length.  zero means that that
+       symbol does not occur in this code.
+
+       The codes are sorted by computing a count of codes for each length,
+       creating from that a table of starting indices for each length in the
+       sorted table, and then entering the symbols in order in the sorted
+       table.  The sorted table is work[], with that space being provided by
+       the caller.
+
+       The length counts are used for other purposes as well, i.e. finding
+       the minimum and maximum length codes, determining if there are any
+       codes at all, checking for a valid set of lengths, and looking ahead
+       at length counts to determine sub-table sizes when building the
+       decoding tables.
+     */
+
+    /* accumulate lengths for codes (assumes lens[] all in 0..MAXBITS) */
+    for (len = 0; len <= MAXBITS; len++)
+        count[len] = 0;
+    for (sym = 0; sym < codes; sym++)
+        count[lens[sym]]++;
+
+    /* bound code lengths, force root to be within code lengths */
+    root = *bits;
+    for (max = MAXBITS; max >= 1; max--)
+        if (count[max] != 0) break;
+    if (root > max) root = max;
+    if (max == 0) {                     /* no symbols to code at all */
+        this.op = (unsigned char)64;    /* invalid code marker */
+        this.bits = (unsigned char)1;
+        this.val = (unsigned short)0;
+        *(*table)++ = this;             /* make a table to force an error */
+        *(*table)++ = this;
+        *bits = 1;
+        return 0;     /* no symbols, but wait for decoding to report error */
+    }
+    for (min = 1; min <= MAXBITS; min++)
+        if (count[min] != 0) break;
+    if (root < min) root = min;
+
+    /* check for an over-subscribed or incomplete set of lengths */
+    left = 1;
+    for (len = 1; len <= MAXBITS; len++) {
+        left <<= 1;
+        left -= count[len];
+        if (left < 0) return -1;        /* over-subscribed */
+    }
+    if (left > 0 && (type == CODES || (codes - count[0] != 1)))
+        return -1;                      /* incomplete set */
+
+    /* generate offsets into symbol table for each length for sorting */
+    offs[1] = 0;
+    for (len = 1; len < MAXBITS; len++)
+        offs[len + 1] = offs[len] + count[len];
+
+    /* sort symbols by length, by symbol order within each length */
+    for (sym = 0; sym < codes; sym++)
+        if (lens[sym] != 0) work[offs[lens[sym]]++] = (unsigned short)sym;
+
+    /*
+       Create and fill in decoding tables.  In this loop, the table being
+       filled is at next and has curr index bits.  The code being used is huff
+       with length len.  That code is converted to an index by dropping drop
+       bits off of the bottom.  For codes where len is less than drop + curr,
+       those top drop + curr - len bits are incremented through all values to
+       fill the table with replicated entries.
+
+       root is the number of index bits for the root table.  When len exceeds
+       root, sub-tables are created pointed to by the root entry with an index
+       of the low root bits of huff.  This is saved in low to check for when a
+       new sub-table should be started.  drop is zero when the root table is
+       being filled, and drop is root when sub-tables are being filled.
+
+       When a new sub-table is needed, it is necessary to look ahead in the
+       code lengths to determine what size sub-table is needed.  The length
+       counts are used for this, and so count[] is decremented as codes are
+       entered in the tables.
+
+       used keeps track of how many table entries have been allocated from the
+       provided *table space.  It is checked when a LENS table is being made
+       against the space in *table, ENOUGH, minus the maximum space needed by
+       the worst case distance code, MAXD.  This should never happen, but the
+       sufficiency of ENOUGH has not been proven exhaustively, hence the check.
+       This assumes that when type == LENS, bits == 9.
+
+       sym increments through all symbols, and the loop terminates when
+       all codes of length max, i.e. all codes, have been processed.  This
+       routine permits incomplete codes, so another loop after this one fills
+       in the rest of the decoding tables with invalid code markers.
+     */
+
+    /* set up for code type */
+    switch (type) {
+    case CODES:
+        base = extra = work;    /* dummy value--not used */
+        end = 19;
+        break;
+    case LENS:
+        base = lbase;
+        base -= 257;
+        extra = lext;
+        extra -= 257;
+        end = 256;
+        break;
+    default:            /* DISTS */
+        base = dbase;
+        extra = dext;
+        end = -1;
+    }
 
-  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 uIntf *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 */
-  uIntf *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                            /* 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;                       /* no tables yet--level -1 */
-  w = -l;                       /* bits decoded == (l * h) */
-  u[0] = (inflate_huft *)Z_NULL;        /* just to keep compilers happy */
-  q = (inflate_huft *)Z_NULL;   /* ditto */
-  z = 0;                        /* ditto */
-
-  /* go through the bit lengths (k already is bits in shortest code) */
-  for (; k <= g; k++)
-  {
-    a = c[k];
-    while (a--)
-    {
-      /* here i is the Huffman code of length k bits for value *p */
-      /* make tables up to required level */
-      while (k > w + l)
-      {
-        h++;
-        w += l;                 /* previous table always l bits */
-
-        /* compute minimum size table less than or equal to l bits */
-        z = g - w;
-        z = z > (uInt)l ? l : z;        /* table size upper limit */
-        if ((f = 1 << (j = k - w)) > a + 1)     /* try a k-w bit table */
-        {                       /* too few codes for k-w bit table */
-          f -= a + 1;           /* deduct codes from patterns left */
-          xp = c + k;
-          if (j < z)
-            while (++j < z)     /* try smaller tables up to z bits */
-            {
-              if ((f <<= 1) <= *++xp)
-                break;          /* enough codes to use up j bits */
-              f -= *xp;         /* else deduct codes from patterns */
-            }
+    /* initialize state for loop */
+    huff = 0;                   /* starting code */
+    sym = 0;                    /* starting code symbol */
+    len = min;                  /* starting code length */
+    next = *table;              /* current table to fill in */
+    curr = root;                /* current table index bits */
+    drop = 0;                   /* current bits to drop from code for index */
+    low = (unsigned)(-1);       /* trigger new sub-table when len > root */
+    used = 1U << root;          /* use root table entries */
+    mask = used - 1;            /* mask for comparing low */
+
+    /* check available table space */
+    if (type == LENS && used >= ENOUGH - MAXD)
+        return 1;
+
+    /* process all codes and make table entries */
+    for (;;) {
+        /* create table entry */
+        this.bits = (unsigned char)(len - drop);
+        if ((int)(work[sym]) < end) {
+            this.op = (unsigned char)0;
+            this.val = work[sym];
         }
-        z = 1 << j;             /* table entries for j-bit table */
-
-        /* allocate new table */
-        if (*hn + z > MANY)     /* (note: doesn't matter for fixed) */
-          return Z_DATA_ERROR;  /* overflow of MANY */
-        u[h] = q = hp + *hn;
-        *hn += z;
-
-        /* connect to last table, if there is one */
-        if (h)
-        {
-          x[h] = i;             /* save pattern for backing up */
-          r.bits = (Byte)l;     /* bits to dump before this table */
-          r.exop = (Byte)j;     /* bits in this table */
-          j = i >> (w - l);
-          r.base = (uInt)(q - u[h-1] - j);   /* offset to this table */
-          u[h-1][j] = r;        /* connect to last table */
+        else if ((int)(work[sym]) > end) {
+            this.op = (unsigned char)(extra[work[sym]]);
+            this.val = base[work[sym]];
+        }
+        else {
+            this.op = (unsigned char)(32 + 64);         /* end of block */
+            this.val = 0;
         }
-        else
-          *t = q;               /* first table is returned result */
-      }
-
-      /* set up table entry in r */
-      r.bits = (Byte)(k - w);
-      if (p >= v + n)
-        r.exop = 128 + 64;      /* out of values--invalid code */
-      else if (*p < s)
-      {
-        r.exop = (Byte)(*p < 256 ? 0 : 32 + 64);     /* 256 is end-of-block */
-        r.base = *p++;          /* simple code is just the value */
-      }
-      else
-      {
-        r.exop = (Byte)(e[*p - s] + 16 + 64);/* non-simple--look up in lists */
-        r.base = d[*p++ - s];
-      }
-
-      /* fill code-like entries with r */
-      f = 1 << (k - w);
-      for (j = i >> w; j < z; j += f)
-        q[j] = r;
-
-      /* backwards increment the k-bit code i */
-      for (j = 1 << (k - 1); i & j; j >>= 1)
-        i ^= j;
-      i ^= j;
-
-      /* backup over finished tables */
-      mask = (1 << w) - 1;      /* needed on HP, cc -O bug */
-      while ((i & mask) != x[h])
-      {
-        h--;                    /* don't need to update q */
-        w -= l;
-        mask = (1 << w) - 1;
-      }
-    }
-  }
-
 
-  /* Return Z_BUF_ERROR if we were given an incomplete table */
-  return y != 0 && g != 1 ? Z_BUF_ERROR : Z_OK;
-}
+        /* replicate for those indices with low len bits equal to huff */
+        incr = 1U << (len - drop);
+        fill = 1U << curr;
+        do {
+            fill -= incr;
+            next[(huff >> drop) + fill] = this;
+        } while (fill != 0);
+
+        /* backwards increment the len-bit code huff */
+        incr = 1U << (len - 1);
+        while (huff & incr)
+            incr >>= 1;
+        if (incr != 0) {
+            huff &= incr - 1;
+            huff += incr;
+        }
+        else
+            huff = 0;
 
+        /* go to next symbol, update count, len */
+        sym++;
+        if (--(count[len]) == 0) {
+            if (len == max) break;
+            len = lens[work[sym]];
+        }
 
-int inflate_trees_bits(c, bb, tb, hp, z)
-uIntf *c;               /* 19 code lengths */
-uIntf *bb;              /* bits tree desired/actual depth */
-inflate_huft * FAR *tb; /* bits tree result */
-inflate_huft *hp;       /* space for trees */
-z_streamp z;            /* for messages */
-{
-  int r;
-  uInt hn = 0;          /* hufts used in space */
-  uIntf *v;             /* work area for huft_build */
-
-  if ((v = (uIntf*)ZALLOC(z, 19, sizeof(uInt))) == Z_NULL)
-    return Z_MEM_ERROR;
-  r = huft_build(c, 19, 19, (uIntf*)Z_NULL, (uIntf*)Z_NULL,
-                 tb, bb, hp, &hn, v);
-  if (r == Z_DATA_ERROR)
-    z->msg = (char*)"oversubscribed dynamic bit lengths tree";
-  else if (r == Z_BUF_ERROR || *bb == 0)
-  {
-    z->msg = (char*)"incomplete dynamic bit lengths tree";
-    r = Z_DATA_ERROR;
-  }
-  ZFREE(z, v);
-  return r;
-}
+        /* create new sub-table if needed */
+        if (len > root && (huff & mask) != low) {
+            /* if first time, transition to sub-tables */
+            if (drop == 0)
+                drop = root;
+
+            /* increment past last table */
+            next += 1U << curr;
+
+            /* determine length of next table */
+            curr = len - drop;
+            left = (int)(1 << curr);
+            while (curr + drop < max) {
+                left -= count[curr + drop];
+                if (left <= 0) break;
+                curr++;
+                left <<= 1;
+            }
 
+            /* check for enough space */
+            used += 1U << curr;
+            if (type == LENS && used >= ENOUGH - MAXD)
+                return 1;
 
-int inflate_trees_dynamic(nl, nd, c, bl, bd, tl, td, hp, z)
-uInt nl;                /* number of literal/length codes */
-uInt nd;                /* number of distance codes */
-uIntf *c;               /* that many (total) code lengths */
-uIntf *bl;              /* literal desired/actual bit depth */
-uIntf *bd;              /* distance desired/actual bit depth */
-inflate_huft * FAR *tl; /* literal/length tree result */
-inflate_huft * FAR *td; /* distance tree result */
-inflate_huft *hp;       /* space for trees */
-z_streamp z;            /* for messages */
-{
-  int r;
-  uInt hn = 0;          /* hufts used in space */
-  uIntf *v;             /* work area for huft_build */
-
-  /* allocate work area */
-  if ((v = (uIntf*)ZALLOC(z, 288, sizeof(uInt))) == Z_NULL)
-    return Z_MEM_ERROR;
-
-  /* build literal/length tree */
-  r = huft_build(c, nl, 257, cplens, cplext, tl, bl, hp, &hn, v);
-  if (r != Z_OK || *bl == 0)
-  {
-    if (r == Z_DATA_ERROR)
-      z->msg = (char*)"oversubscribed literal/length tree";
-    else if (r != Z_MEM_ERROR)
-    {
-      z->msg = (char*)"incomplete literal/length tree";
-      r = Z_DATA_ERROR;
-    }
-    ZFREE(z, v);
-    return r;
-  }
-
-  /* build distance tree */
-  r = huft_build(c + nl, nd, 0, cpdist, cpdext, td, bd, hp, &hn, v);
-  if (r != Z_OK || (*bd == 0 && nl > 257))
-  {
-    if (r == Z_DATA_ERROR)
-      z->msg = (char*)"oversubscribed distance tree";
-    else if (r == Z_BUF_ERROR) {
-#ifdef PKZIP_BUG_WORKAROUND
-      r = Z_OK;
-    }
-#else
-      z->msg = (char*)"incomplete distance tree";
-      r = Z_DATA_ERROR;
-    }
-    else if (r != Z_MEM_ERROR)
-    {
-      z->msg = (char*)"empty distance tree with lengths";
-      r = Z_DATA_ERROR;
+            /* point entry in root table to sub-table */
+            low = huff & mask;
+            (*table)[low].op = (unsigned char)curr;
+            (*table)[low].bits = (unsigned char)root;
+            (*table)[low].val = (unsigned short)(next - *table);
+        }
     }
-    ZFREE(z, v);
-    return r;
-#endif
-  }
-
-  /* done */
-  ZFREE(z, v);
-  return Z_OK;
-}
 
+    /*
+       Fill in rest of table for incomplete codes.  This loop is similar to the
+       loop above in incrementing huff for table indices.  It is assumed that
+       len is equal to curr + drop, so there is no loop needed to increment
+       through high index bits.  When the current sub-table is filled, the loop
+       drops back to the root table to fill in any remaining entries there.
+     */
+    this.op = (unsigned char)64;                /* invalid code marker */
+    this.bits = (unsigned char)(len - drop);
+    this.val = (unsigned short)0;
+    while (huff != 0) {
+        /* when done with sub-table, drop back to root table */
+        if (drop != 0 && (huff & mask) != low) {
+            drop = 0;
+            len = root;
+            next = *table;
+            this.bits = (unsigned char)len;
+        }
 
-/* build fixed tables only once--keep them here */
-#ifdef BUILDFIXED
-local int fixed_built = 0;
-#define FIXEDH 544      /* number of hufts used by fixed tables */
-local inflate_huft fixed_mem[FIXEDH];
-local uInt fixed_bl;
-local uInt fixed_bd;
-local inflate_huft *fixed_tl;
-local inflate_huft *fixed_td;
-#else
-#include "inffixed.h"
-#endif
-
-
-int inflate_trees_fixed(bl, bd, tl, td, z)
-uIntf *bl;               /* literal desired/actual bit depth */
-uIntf *bd;               /* distance desired/actual bit depth */
-inflate_huft * FAR *tl;  /* literal/length tree result */
-inflate_huft * FAR *td;  /* distance tree result */
-z_streamp z;             /* for memory allocation */
-{
-#ifdef BUILDFIXED
-  /* build fixed tables if not already */
-  if (!fixed_built)
-  {
-    int k;              /* temporary variable */
-    uInt f = 0;         /* number of hufts used in fixed_mem */
-    uIntf *c;           /* length list for huft_build */
-    uIntf *v;           /* work area for huft_build */
-
-    /* allocate memory */
-    if ((c = (uIntf*)ZALLOC(z, 288, sizeof(uInt))) == Z_NULL)
-      return Z_MEM_ERROR;
-    if ((v = (uIntf*)ZALLOC(z, 288, sizeof(uInt))) == Z_NULL)
-    {
-      ZFREE(z, c);
-      return Z_MEM_ERROR;
+        /* put invalid code marker in table */
+        next[huff >> drop] = this;
+
+        /* backwards increment the len-bit code huff */
+        incr = 1U << (len - 1);
+        while (huff & incr)
+            incr >>= 1;
+        if (incr != 0) {
+            huff &= incr - 1;
+            huff += incr;
+        }
+        else
+            huff = 0;
     }
 
-    /* literal table */
-    for (k = 0; k < 144; k++)
-      c[k] = 8;
-    for (; k < 256; k++)
-      c[k] = 9;
-    for (; k < 280; k++)
-      c[k] = 7;
-    for (; k < 288; k++)
-      c[k] = 8;
-    fixed_bl = 9;
-    huft_build(c, 288, 257, cplens, cplext, &fixed_tl, &fixed_bl,
-               fixed_mem, &f, v);
-
-    /* distance table */
-    for (k = 0; k < 30; k++)
-      c[k] = 5;
-    fixed_bd = 5;
-    huft_build(c, 30, 0, cpdist, cpdext, &fixed_td, &fixed_bd,
-               fixed_mem, &f, v);
-
-    /* done */
-    ZFREE(z, v);
-    ZFREE(z, c);
-    fixed_built = 1;
-  }
-#endif
-  *bl = fixed_bl;
-  *bd = fixed_bd;
-  *tl = fixed_tl;
-  *td = fixed_td;
-  return Z_OK;
+    /* set return parameters */
+    *table += used;
+    *bits = root;
+    return 0;
 }