diff options
Diffstat (limited to 'inftrees.h')
-rw-r--r-- | inftrees.h | 91 |
1 files changed, 44 insertions, 47 deletions
@@ -1,6 +1,6 @@ | |||
1 | /* inftrees.h -- header to use inftrees.c | 1 | /* inftrees.h -- header to use inftrees.c |
2 | * Copyright (C) 1995-2002 Mark Adler | 2 | * Copyright (C) 1995-2003 Mark Adler |
3 | * For conditions of distribution and use, see copyright notice in zlib.h | 3 | * For conditions of distribution and use, see copyright notice in zlib.h |
4 | */ | 4 | */ |
5 | 5 | ||
6 | /* WARNING: this file should *not* be used by applications. It is | 6 | /* WARNING: this file should *not* be used by applications. It is |
@@ -8,51 +8,48 @@ | |||
8 | subject to change. Applications should only use zlib.h. | 8 | subject to change. Applications should only use zlib.h. |
9 | */ | 9 | */ |
10 | 10 | ||
11 | /* Huffman code lookup table entry--this entry is four bytes for machines | 11 | /* Structure for decoding tables. Each entry provides either the |
12 | that have 16-bit pointers (e.g. PC's in the small or medium model). */ | 12 | information needed to do the operation requested by the code that |
13 | 13 | indexed that table entry, or it provides a pointer to another | |
14 | typedef struct inflate_huft_s FAR inflate_huft; | 14 | table that indexes more bits of the code. op indicates whether |
15 | 15 | the entry is a pointer to another table, a literal, a length or | |
16 | struct inflate_huft_s { | 16 | distance, an end-of-block, or an invalid code. For a table |
17 | union { | 17 | pointer, the low four bits of op is the number of index bits of |
18 | struct { | 18 | that table. For a length or distance, the low four bits of op |
19 | Byte Exop; /* number of extra bits or operation */ | 19 | is the number of extra bits to get after the code. bits is |
20 | Byte Bits; /* number of bits in this code or subcode */ | 20 | the number of bits in this code or part of the code to drop off |
21 | } what; | 21 | of the bit buffer. val is the actual byte to output in the case |
22 | uInt pad; /* pad structure to a power of 2 (4 bytes for */ | 22 | of a literal, the base length or distance, or the offset from |
23 | } word; /* 16-bit, 8 bytes for 32-bit int's) */ | 23 | the current table to the next table. Each entry is four bytes. */ |
24 | uInt base; /* literal, length base, distance base, | 24 | typedef struct { |
25 | or table offset */ | 25 | unsigned char op; /* operation, extra bits, table bits */ |
26 | }; | 26 | unsigned char bits; /* bits in this part of the code */ |
27 | unsigned short val; /* offset in table or code value */ | ||
28 | } code; | ||
29 | |||
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 | */ | ||
27 | 37 | ||
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 | 41 | exhaustive search). The true maximum is not known, but the value |
32 | value below is more than safe. */ | 42 | below is more than safe. */ |
33 | #define MANY 1440 | 43 | #define ENOUGH 1440 |
34 | 44 | #define MAXD 154 | |
35 | extern int inflate_trees_bits OF(( | 45 | |
36 | uIntf *, /* 19 code lengths */ | 46 | /* Type of code to build for inftable() */ |
37 | uIntf *, /* bits tree desired/actual depth */ | 47 | typedef enum { |
38 | inflate_huft * FAR *, /* bits tree result */ | 48 | CODES, |
39 | inflate_huft *, /* space for trees */ | 49 | LENS, |
40 | z_streamp)); /* for messages */ | 50 | DISTS |
41 | 51 | } codetype; | |
42 | extern int inflate_trees_dynamic OF(( | 52 | |
43 | uInt, /* number of literal/length codes */ | 53 | extern int inflate_table OF((codetype type, unsigned short FAR *lens, |
44 | uInt, /* number of distance codes */ | 54 | unsigned codes, code * FAR *table, unsigned *bits, |
45 | uIntf *, /* that many (total) code lengths */ | 55 | unsigned short FAR *work)); |
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 | |||
53 | extern 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 */ | ||