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/platform.h"
  13 #include <brotli/types.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, 1112, 1144, 1176, 1208, 1240, 1272,
  26   1304, 1336, 1368, 1400, 1432, 1464, 1496, 1528};
  27 /* BROTLI_NUM_BLOCK_LEN_SYMBOLS == 26 */
  28 #define BROTLI_HUFFMAN_MAX_SIZE_26 396
  29 /* BROTLI_MAX_BLOCK_TYPE_SYMBOLS == 258 */
  30 #define BROTLI_HUFFMAN_MAX_SIZE_258 632
  31 /* BROTLI_MAX_CONTEXT_MAP_SYMBOLS == 272 */
  32 #define BROTLI_HUFFMAN_MAX_SIZE_272 646
  33
  34 #define BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH 5
  35
  36 typedef struct {
  37   uint8_t bits;    /* number of bits used for this symbol */
  38   uint16_t value;  /* symbol value or table offset */
  39 } HuffmanCode;
  40
  41 /* Builds Huffman lookup table assuming code lengths are in symbol order. */
  42 BROTLI_INTERNAL void BrotliBuildCodeLengthsHuffmanTable(HuffmanCode* root_table,
  43     const uint8_t* const code_lengths, uint16_t* count);
  44
  45 /* Builds Huffman lookup table assuming code lengths are in symbol order.
  46    Returns size of resulting table. */
  47 BROTLI_INTERNAL uint32_t BrotliBuildHuffmanTable(HuffmanCode* root_table,
  48     int root_bits, const uint16_t* const symbol_lists, uint16_t* count_arg);
  49
  50 /* Builds a simple Huffman table. The |num_symbols| parameter is to be
  51    interpreted as follows: 0 means 1 symbol, 1 means 2 symbols,
  52    2 means 3 symbols, 3 means 4 symbols with lengths [2, 2, 2, 2],
  53    4 means 4 symbols with lengths [1, 2, 3, 3]. */
  54 BROTLI_INTERNAL uint32_t BrotliBuildSimpleHuffmanTable(HuffmanCode* table,
  55     int root_bits, uint16_t* symbols, uint32_t num_symbols);
  56
  57 /* Contains a collection of Huffman trees with the same alphabet size. */
  58 /* max_symbol is needed due to simple codes since log2(alphabet_size) could be
  59    greater than log2(max_symbol). */
  60 typedef struct {
  61   HuffmanCode** htrees;
  62   HuffmanCode* codes;
  63   uint16_t alphabet_size;
  64   uint16_t max_symbol;
  65   uint16_t num_htrees;
  66 } HuffmanTreeGroup;
  67
  68 #if defined(__cplusplus) || defined(c_plusplus)
  69 }  /* extern "C" */
  70 #endif
  71
  72 #endif  /* BROTLI_DEC_HUFFMAN_H_ */