diff options
Diffstat (limited to 'zlib/inftrees.c')
| -rw-r--r-- | zlib/inftrees.c | 454 |
1 files changed, 0 insertions, 454 deletions
diff --git a/zlib/inftrees.c b/zlib/inftrees.c deleted file mode 100644 index 4c32ca30d..000000000 --- a/zlib/inftrees.c +++ /dev/null @@ -1,454 +0,0 @@ -/* 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 - */ - -#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 1.1.4 Copyright 1995-2002 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), 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 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_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 - *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; -} |