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diff --git a/libpng/inftrees.c b/libpng/inftrees.c
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+/* 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
+ */
+
+#include "zutil.h"
+#include "inftrees.h"
+
+#if !defined(BUILDFIXED) && !defined(STDC)
+# define BUILDFIXED /* non ANSI compilers may not accept inffixed.h */
+#endif
+
+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.
+ */
+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.
+ */
+
+
+/* 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), Z_DATA_ERROR if the input is invalid (an over-subscribed set of
+ lengths), or Z_MEM_ERROR if not enough memory. */
+{
+
+ 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 */
+ }
+ }
+ z = 1 << j; /* table entries for j-bit table */
+
+ /* allocate new table */
+ if (*hn + z > MANY) /* (note: doesn't matter for fixed) */
+ return Z_MEM_ERROR; /* not enough memory */
+ 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
+ *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;
+}
+
+
+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;
+}
+
+
+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;
+ }
+ ZFREE(z, v);
+ return r;
+#endif
+ }
+
+ /* done */
+ ZFREE(z, v);
+ return Z_OK;
+}
+
+
+/* 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;
+ }
+
+ /* 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;
+}