/* 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
+ * Copyright (C) 1995-2005 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 1.1.3 Copyright 1995-1998 Mark Adler ";
+ " inflate 1.2.3 Copyright 1995-2005 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), Z_DATA_ERROR if the input is invalid (an over-subscribed set of
- lengths), or Z_MEM_ERROR if not enough memory. */
+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, 201, 196};
+ 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 || max != 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_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 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;
+ min = fill; /* save offset to next table */
+ 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 += min; /* here min is 1 << 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;
}
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