kc3-lang/brotli/dec/huffman.h

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• Hash : f1c9ab29
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  Date : 2016-06-03T10:51:04
  

  Extract common parts: constants, dictionary, etc.
  

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• dec/huffman.h

• /* Copyright 2013 Google Inc. All Rights Reserved.
  
     Distributed under MIT license.
     See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
  */
  
  /* Utilities for building Huffman decoding tables. */
  
  #ifndef BROTLI_DEC_HUFFMAN_H_
  #define BROTLI_DEC_HUFFMAN_H_
  
  #include "../common/types.h"
  #include "./port.h"
  
  #if defined(__cplusplus) || defined(c_plusplus)
  extern "C" {
  #endif
  
  #define BROTLI_HUFFMAN_MAX_CODE_LENGTH 15
  
  /* Maximum possible Huffman table size for an alphabet size of (index * 32),
   * max code length 15 and root table bits 8. */
  static const uint16_t kMaxHuffmanTableSize[] = {
    256, 402, 436, 468, 500, 534, 566, 598, 630, 662, 694, 726, 758, 790, 822,
    854, 886, 920, 952, 984, 1016, 1048, 1080};
  /* BROTLI_NUM_BLOCK_LEN_SYMBOLS == 26 */
  #define BROTLI_HUFFMAN_MAX_SIZE_26 396
  /* BROTLI_MAX_BLOCK_TYPE_SYMBOLS == 258 */
  #define BROTLI_HUFFMAN_MAX_SIZE_258 632
  /* BROTLI_MAX_CONTEXT_MAP_SYMBOLS == 272 */
  #define BROTLI_HUFFMAN_MAX_SIZE_272 646
  
  #define BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH 5
  
  typedef struct {
    uint8_t bits;    /* number of bits used for this symbol */
    uint16_t value;  /* symbol value or table offset */
  } HuffmanCode;
  
  /* Builds Huffman lookup table assuming code lengths are in symbol order. */
  BROTLI_INTERNAL void BrotliBuildCodeLengthsHuffmanTable(HuffmanCode* root_table,
      const uint8_t* const code_lengths, uint16_t* count);
  
  /* Builds Huffman lookup table assuming code lengths are in symbol order. */
  /* Returns size of resulting table. */
  BROTLI_INTERNAL uint32_t BrotliBuildHuffmanTable(HuffmanCode* root_table,
      int root_bits, const uint16_t* const symbol_lists, uint16_t* count_arg);
  
  /* Builds a simple Huffman table. The num_symbols parameter is to be */
  /* interpreted as follows: 0 means 1 symbol, 1 means 2 symbols, 2 means 3 */
  /* symbols, 3 means 4 symbols with lengths 2,2,2,2, 4 means 4 symbols with */
  /* lengths 1,2,3,3. */
  BROTLI_INTERNAL uint32_t BrotliBuildSimpleHuffmanTable(HuffmanCode* table,
      int root_bits, uint16_t* symbols, uint32_t num_symbols);
  
  /* Contains a collection of Huffman trees with the same alphabet size. */
  typedef struct {
    HuffmanCode** htrees;
    HuffmanCode* codes;
    uint16_t alphabet_size;
    uint16_t num_htrees;
  } HuffmanTreeGroup;
  
  #if defined(__cplusplus) || defined(c_plusplus)
  }  /* extern "C" */
  #endif
  
  #endif  /* BROTLI_DEC_HUFFMAN_H_ */
  

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