ead502dd7fceceec477b1f0ac88be40acd87941a
[mirror_edk2.git] / MdeModulePkg / Library / BrotliCustomDecompressLib / dec / huffman.h
1 /* Copyright 2013 Google Inc. All Rights Reserved.
2
3 Distributed under MIT license.
4 See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
5 */
6
7 /* Utilities for building Huffman decoding tables. */
8
9 #ifndef BROTLI_DEC_HUFFMAN_H_
10 #define BROTLI_DEC_HUFFMAN_H_
11
12 #include "../common/types.h"
13 #include "./port.h"
14
15 #if defined(__cplusplus) || defined(c_plusplus)
16 extern "C" {
17 #endif
18
19 #define BROTLI_HUFFMAN_MAX_CODE_LENGTH 15
20
21 /* Maximum possible Huffman table size for an alphabet size of (index * 32),
22 * max code length 15 and root table bits 8. */
23 static const uint16_t kMaxHuffmanTableSize[] = {
24 256, 402, 436, 468, 500, 534, 566, 598, 630, 662, 694, 726, 758, 790, 822,
25 854, 886, 920, 952, 984, 1016, 1048, 1080};
26 /* BROTLI_NUM_BLOCK_LEN_SYMBOLS == 26 */
27 #define BROTLI_HUFFMAN_MAX_SIZE_26 396
28 /* BROTLI_MAX_BLOCK_TYPE_SYMBOLS == 258 */
29 #define BROTLI_HUFFMAN_MAX_SIZE_258 632
30 /* BROTLI_MAX_CONTEXT_MAP_SYMBOLS == 272 */
31 #define BROTLI_HUFFMAN_MAX_SIZE_272 646
32
33 #define BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH 5
34
35 typedef struct {
36 uint8_t bits; /* number of bits used for this symbol */
37 uint16_t value; /* symbol value or table offset */
38 } HuffmanCode;
39
40 /* Builds Huffman lookup table assuming code lengths are in symbol order. */
41 BROTLI_INTERNAL void BrotliBuildCodeLengthsHuffmanTable(HuffmanCode* root_table,
42 const uint8_t* const code_lengths, uint16_t* count);
43
44 /* Builds Huffman lookup table assuming code lengths are in symbol order. */
45 /* Returns size of resulting table. */
46 BROTLI_INTERNAL uint32_t BrotliBuildHuffmanTable(HuffmanCode* root_table,
47 int root_bits, const uint16_t* const symbol_lists, uint16_t* count_arg);
48
49 /* Builds a simple Huffman table. The num_symbols parameter is to be */
50 /* interpreted as follows: 0 means 1 symbol, 1 means 2 symbols, 2 means 3 */
51 /* symbols, 3 means 4 symbols with lengths 2,2,2,2, 4 means 4 symbols with */
52 /* lengths 1,2,3,3. */
53 BROTLI_INTERNAL uint32_t BrotliBuildSimpleHuffmanTable(HuffmanCode* table,
54 int root_bits, uint16_t* symbols, uint32_t num_symbols);
55
56 /* Contains a collection of Huffman trees with the same alphabet size. */
57 typedef struct {
58 HuffmanCode** htrees;
59 HuffmanCode* codes;
60 uint16_t alphabet_size;
61 uint16_t num_htrees;
62 } HuffmanTreeGroup;
63
64 #if defined(__cplusplus) || defined(c_plusplus)
65 } /* extern "C" */
66 #endif
67
68 #endif /* BROTLI_DEC_HUFFMAN_H_ */