1 #ifndef INFTREES_H
2 #define INFTREES_H
3
4 /* inftrees.h -- header to use inftrees.c
5 * Copyright (C) 1995-2005 Mark Adler
6 * For conditions of distribution and use, see copyright notice in zlib.h
7 */
8
9 /* WARNING: this file should *not* be used by applications. It is
10 part of the implementation of the compression library and is
11 subject to change. Applications should only use zlib.h.
12 */
13
14 /* Structure for decoding tables. Each entry provides either the
15 information needed to do the operation requested by the code that
16 indexed that table entry, or it provides a pointer to another
17 table that indexes more bits of the code. op indicates whether
18 the entry is a pointer to another table, a literal, a length or
19 distance, an end-of-block, or an invalid code. For a table
20 pointer, the low four bits of op is the number of index bits of
21 that table. For a length or distance, the low four bits of op
22 is the number of extra bits to get after the code. bits is
23 the number of bits in this code or part of the code to drop off
24 of the bit buffer. val is the actual byte to output in the case
25 of a literal, the base length or distance, or the offset from
26 the current table to the next table. Each entry is four bytes. */
27 typedef struct {
28 unsigned char op; /* operation, extra bits, table bits */
29 unsigned char bits; /* bits in this part of the code */
30 unsigned short val; /* offset in table or code value */
31 } code;
32
33 /* op values as set by inflate_table():
34 00000000 - literal
35 0000tttt - table link, tttt != 0 is the number of table index bits
36 0001eeee - length or distance, eeee is the number of extra bits
37 01100000 - end of block
38 01000000 - invalid code
39 */
40
41 /* Maximum size of dynamic tree. The maximum found in a long but non-
42 exhaustive search was 1444 code structures (852 for length/literals
43 and 592 for distances, the latter actually the result of an
44 exhaustive search). The true maximum is not known, but the value
45 below is more than safe. */
46 #define ENOUGH 2048
47 #define MAXD 592
48
49 /* Type of code to build for inftable() */
50 typedef enum {
51 CODES,
52 LENS,
53 DISTS
54 } codetype;
55
56 extern int zlib_inflate_table (codetype type, unsigned short *lens,
57 unsigned codes, code **table,
58 unsigned *bits, unsigned short *work);
59 #endif