kc3-lang/brotli/c/enc/backward_references.c

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• Hash : fe754f34
  Author :
  Date : 2024-05-30T09:50:58
  

  Use a hash table header and SIMD to speed up hash table operations (similar to [Swiss Tables](https://abseil.io/about/design/swisstables)).
  
  PiperOrigin-RevId: 638686412
  

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• c/enc/backward_references.c

• /* Copyright 2013 Google Inc. All Rights Reserved.
  
     Distributed under MIT license.
     See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
  */
  
  /* Function to find backward reference copies. */
  
  #include "backward_references.h"
  
  #include <brotli/types.h>
  
  #include "../common/constants.h"
  #include "../common/dictionary.h"
  #include "../common/platform.h"
  #include "command.h"
  #include "compound_dictionary.h"
  #include "dictionary_hash.h"
  #include "encoder_dict.h"
  #include "memory.h"
  #include "quality.h"
  
  #if defined(__cplusplus) || defined(c_plusplus)
  extern "C" {
  #endif
  
  static BROTLI_INLINE size_t ComputeDistanceCode(size_t distance,
                                                  size_t max_distance,
                                                  const int* dist_cache) {
    if (distance <= max_distance) {
      size_t distance_plus_3 = distance + 3;
      size_t offset0 = distance_plus_3 - (size_t)dist_cache[0];
      size_t offset1 = distance_plus_3 - (size_t)dist_cache[1];
      if (distance == (size_t)dist_cache[0]) {
        return 0;
      } else if (distance == (size_t)dist_cache[1]) {
        return 1;
      } else if (offset0 < 7) {
        return (0x9750468 >> (4 * offset0)) & 0xF;
      } else if (offset1 < 7) {
        return (0xFDB1ACE >> (4 * offset1)) & 0xF;
      } else if (distance == (size_t)dist_cache[2]) {
        return 2;
      } else if (distance == (size_t)dist_cache[3]) {
        return 3;
      }
    }
    return distance + BROTLI_NUM_DISTANCE_SHORT_CODES - 1;
  }
  
  #define EXPAND_CAT(a, b) CAT(a, b)
  #define CAT(a, b) a ## b
  #define FN(X) EXPAND_CAT(X, HASHER())
  #define EXPORT_FN(X) EXPAND_CAT(X, EXPAND_CAT(PREFIX(), HASHER()))
  
  #define PREFIX() N
  #define ENABLE_COMPOUND_DICTIONARY 0
  
  #define HASHER() H2
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H3
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H4
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H5
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H6
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H40
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H41
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H42
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H54
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H35
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H55
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H65
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #if defined(BROTLI_MAX_SIMD_QUALITY)
  #define HASHER() H58
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  
  #define HASHER() H68
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #endif
  
  #undef ENABLE_COMPOUND_DICTIONARY
  #undef PREFIX
  #define PREFIX() D
  #define ENABLE_COMPOUND_DICTIONARY 1
  
  #define HASHER() H5
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H6
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H40
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H41
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H42
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H55
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H65
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #if defined(BROTLI_MAX_SIMD_QUALITY)
  #define HASHER() H58
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #define HASHER() H68
  /* NOLINTNEXTLINE(build/include) */
  #include "backward_references_inc.h"
  #undef HASHER
  #endif
  
  #undef ENABLE_COMPOUND_DICTIONARY
  #undef PREFIX
  
  #undef EXPORT_FN
  #undef FN
  #undef CAT
  #undef EXPAND_CAT
  
  void BrotliCreateBackwardReferences(size_t num_bytes,
      size_t position, const uint8_t* ringbuffer, size_t ringbuffer_mask,
      ContextLut literal_context_lut, const BrotliEncoderParams* params,
      Hasher* hasher, int* dist_cache, size_t* last_insert_len,
      Command* commands, size_t* num_commands, size_t* num_literals) {
    if (params->dictionary.compound.num_chunks != 0) {
      switch (params->hasher.type) {
  #define CASE_(N)                                                    \
        case N:                                                       \
          CreateBackwardReferencesDH ## N(num_bytes,                  \
              position, ringbuffer, ringbuffer_mask,                  \
              literal_context_lut, params, hasher, dist_cache,        \
              last_insert_len, commands, num_commands, num_literals); \
          return;
        CASE_(5)
        CASE_(6)
  #if defined(BROTLI_MAX_SIMD_QUALITY)
        CASE_(58)
        CASE_(68)
  #endif
        CASE_(40)
        CASE_(41)
        CASE_(42)
        CASE_(55)
        CASE_(65)
  #undef CASE_
        default:
          BROTLI_DCHECK(false);
          break;
      }
    }
  
    switch (params->hasher.type) {
  #define CASE_(N)                                                  \
      case N:                                                       \
        CreateBackwardReferencesNH ## N(num_bytes,                  \
            position, ringbuffer, ringbuffer_mask,                  \
            literal_context_lut, params, hasher, dist_cache,        \
            last_insert_len, commands, num_commands, num_literals); \
        return;
      FOR_GENERIC_HASHERS(CASE_)
  #undef CASE_
      default:
        BROTLI_DCHECK(false);
        break;
    }
  }
  
  #if defined(__cplusplus) || defined(c_plusplus)
  }  /* extern "C" */
  #endif
  

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