kc3-lang/brotli/c/dec/huffman.h

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• Hash : 8a7201c6
  Author :
  Date : 2025-08-05T02:49:08
  

  fix some includes
  
  PiperOrigin-RevId: 791124445
  

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• c/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/platform.h"
  
  #if defined(__cplusplus) || defined(c_plusplus)
  extern "C" {
  #endif
  
  #define BROTLI_HUFFMAN_MAX_CODE_LENGTH 15
  
  /* 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
  
  #if ((defined(BROTLI_TARGET_ARMV7) || defined(BROTLI_TARGET_ARMV8_32)) && \
    BROTLI_GNUC_HAS_ATTRIBUTE(aligned, 2, 7, 0))
  #define BROTLI_HUFFMAN_CODE_FAST_LOAD
  #endif
  
  #if !defined(BROTLI_HUFFMAN_CODE_FAST_LOAD)
  /* Do not create this struct directly - use the ConstructHuffmanCode
   * constructor below! */
  typedef struct {
    uint8_t bits;    /* number of bits used for this symbol */
    uint16_t value;  /* symbol value or table offset */
  } HuffmanCode;
  
  static BROTLI_INLINE HuffmanCode ConstructHuffmanCode(const uint8_t bits,
      const uint16_t value) {
    HuffmanCode h;
    h.bits = bits;
    h.value = value;
    return h;
  }
  
  /* Please use the following macros to optimize HuffmanCode accesses in hot
   * paths.
   *
   * For example, assuming |table| contains a HuffmanCode pointer:
   *
   *   BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table);
   *   BROTLI_HC_ADJUST_TABLE_INDEX(table, index_into_table);
   *   *bits = BROTLI_HC_GET_BITS(table);
   *   *value = BROTLI_HC_GET_VALUE(table);
   *   BROTLI_HC_ADJUST_TABLE_INDEX(table, offset);
   *   *bits2 = BROTLI_HC_GET_BITS(table);
   *   *value2 = BROTLI_HC_GET_VALUE(table);
   *
   */
  
  #define BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(H)
  #define BROTLI_HC_ADJUST_TABLE_INDEX(H, V) H += (V)
  
  /* These must be given a HuffmanCode pointer! */
  #define BROTLI_HC_FAST_LOAD_BITS(H) (H->bits)
  #define BROTLI_HC_FAST_LOAD_VALUE(H) (H->value)
  
  #else /* BROTLI_HUFFMAN_CODE_FAST_LOAD */
  
  typedef BROTLI_ALIGNED(4) uint32_t HuffmanCode;
  
  static BROTLI_INLINE HuffmanCode ConstructHuffmanCode(const uint8_t bits,
      const uint16_t value) {
    return (HuffmanCode) ((value & 0xFFFF) << 16) | (bits & 0xFF);
  }
  
  #define BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(H) uint32_t __fastload_##H = (*H)
  #define BROTLI_HC_ADJUST_TABLE_INDEX(H, V) H += (V); __fastload_##H = (*H)
  
  /* These must be given a HuffmanCode pointer! */
  #define BROTLI_HC_FAST_LOAD_BITS(H) ((__fastload_##H) & 0xFF)
  #define BROTLI_HC_FAST_LOAD_VALUE(H) ((__fastload_##H) >> 16)
  #endif /* BROTLI_HUFFMAN_CODE_FAST_LOAD */
  
  /* 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);
  
  /* 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. */
  /* alphabet_size_limit is needed due to simple codes, since
     log2(alphabet_size_max) could be greater than log2(alphabet_size_limit). */
  typedef struct {
    HuffmanCode** htrees;
    HuffmanCode* codes;
    uint16_t alphabet_size_max;
    uint16_t alphabet_size_limit;
    uint16_t num_htrees;
  } HuffmanTreeGroup;
  
  #if defined(__cplusplus) || defined(c_plusplus)
  }  /* extern "C" */
  #endif
  
  #endif  /* BROTLI_DEC_HUFFMAN_H_ */
  

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