patch-2.4.14 linux/fs/cramfs/inflate/inftrees.c
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- Lines: 393
- Date:
Wed Dec 31 16:00:00 1969
- Orig file:
v2.4.13/linux/fs/cramfs/inflate/inftrees.c
- Orig date:
Wed Apr 12 09:47:29 2000
diff -u --recursive --new-file v2.4.13/linux/fs/cramfs/inflate/inftrees.c linux/fs/cramfs/inflate/inftrees.c
@@ -1,392 +0,0 @@
-/* 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"
-
-static 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 cramfs_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 */
- static unsigned int work_area[19];
-
- v = work_area;
- 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;
- }
- return r;
-}
-
-int cramfs_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 */
- static unsigned int work_area[288];
-
- /* allocate work area */
- v = work_area;
-
- /* 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;
- }
- 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;
- }
- return r;
-#endif
- }
-
- /* done */
- return Z_OK;
-}
-
-
-/* build fixed tables only once--keep them here */
-#include "inffixed.h"
-
-
-int cramfs_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 */
-{
- *bl = fixed_bl;
- *bd = fixed_bd;
- *tl = fixed_tl;
- *td = fixed_td;
- return Z_OK;
-}
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