1/* inftrees.h -- header to use inftrees.c
| 1/* inftrees.h -- header to use inftrees.c
|
2 * Copyright (C) 1995-2002 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
| 2 * Copyright (C) 1995-2003 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
|
4 */
5
6/* WARNING: this file should *not* be used by applications. It is
7 part of the implementation of the compression library and is
8 subject to change. Applications should only use zlib.h.
9 */
10
| 4 */
5
6/* WARNING: this file should *not* be used by applications. It is
7 part of the implementation of the compression library and is
8 subject to change. Applications should only use zlib.h.
9 */
10
|
11/* Huffman code lookup table entry--this entry is four bytes for machines
12 that have 16-bit pointers (e.g. PC's in the small or medium model). */
| 11/* Structure for decoding tables. Each entry provides either the
12 information needed to do the operation requested by the code that
13 indexed that table entry, or it provides a pointer to another
14 table that indexes more bits of the code. op indicates whether
15 the entry is a pointer to another table, a literal, a length or
16 distance, an end-of-block, or an invalid code. For a table
17 pointer, the low four bits of op is the number of index bits of
18 that table. For a length or distance, the low four bits of op
19 is the number of extra bits to get after the code. bits is
20 the number of bits in this code or part of the code to drop off
21 of the bit buffer. val is the actual byte to output in the case
22 of a literal, the base length or distance, or the offset from
23 the current table to the next table. Each entry is four bytes. */
24typedef struct {
25 unsigned char op; /* operation, extra bits, table bits */
26 unsigned char bits; /* bits in this part of the code */
27 unsigned short val; /* offset in table or code value */
28} code;
|
13
| 29
|
14typedef struct inflate_huft_s FAR inflate_huft;
| 30/* op values as set by inflate_table():
31 00000000 - literal
32 0000tttt - table link, tttt != 0 is the number of table index bits
33 0001eeee - length or distance, eeee is the number of extra bits
34 01100000 - end of block
35 01000000 - invalid code
36 */
|
15
| 37
|
16struct inflate_huft_s {
17 union {
18 struct {
19 Byte Exop; /* number of extra bits or operation */
20 Byte Bits; /* number of bits in this code or subcode */
21 } what;
22 uInt pad; /* pad structure to a power of 2 (4 bytes for */
23 } word; /* 16-bit, 8 bytes for 32-bit int's) */
24 uInt base; /* literal, length base, distance base,
25 or table offset */
26};
27
| |
28/* Maximum size of dynamic tree. The maximum found in a long but non-
| 38/* Maximum size of dynamic tree. The maximum found in a long but non-
|
29 exhaustive search was 1004 huft structures (850 for length/literals
| 39 exhaustive search was 1004 code structures (850 for length/literals
|
30 and 154 for distances, the latter actually the result of an
| 40 and 154 for distances, the latter actually the result of an
|
31 exhaustive search). The actual maximum is not known, but the
32 value below is more than safe. */
33#define MANY 1440
| 41 exhaustive search). The true maximum is not known, but the value
42 below is more than safe. */
43#define ENOUGH 1440
44#define MAXD 154
|
34
| 45
|
35extern int inflate_trees_bits OF((
36 uIntf *, /* 19 code lengths */
37 uIntf *, /* bits tree desired/actual depth */
38 inflate_huft * FAR *, /* bits tree result */
39 inflate_huft *, /* space for trees */
40 z_streamp)); /* for messages */
| 46/* Type of code to build for inftable() */
47typedef enum {
48 CODES,
49 LENS,
50 DISTS
51} codetype;
|
41
| 52
|
42extern int inflate_trees_dynamic OF((
43 uInt, /* number of literal/length codes */
44 uInt, /* number of distance codes */
45 uIntf *, /* that many (total) code lengths */
46 uIntf *, /* literal desired/actual bit depth */
47 uIntf *, /* distance desired/actual bit depth */
48 inflate_huft * FAR *, /* literal/length tree result */
49 inflate_huft * FAR *, /* distance tree result */
50 inflate_huft *, /* space for trees */
51 z_streamp)); /* for messages */
52
53extern int inflate_trees_fixed OF((
54 uIntf *, /* literal desired/actual bit depth */
55 uIntf *, /* distance desired/actual bit depth */
56 inflate_huft * FAR *, /* literal/length tree result */
57 inflate_huft * FAR *, /* distance tree result */
58 z_streamp)); /* for memory allocation */
| 53extern int inflate_table OF((codetype type, unsigned short FAR *lens,
54 unsigned codes, code FAR * FAR *table,
55 unsigned FAR *bits, unsigned short FAR *work));
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| |