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_ */