kc3-lang/brotli/c/enc/hash_base.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/enc/hash_base.h

• /* Copyright 2025 Google Inc. All Rights Reserved.
  
     Distributed under MIT license.
     See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
  */
  
  /* Basic common hash functions / constants. */
  
  #ifndef THIRD_PARTY_BROTLI_ENC_HASH_BASE_H_
  #define THIRD_PARTY_BROTLI_ENC_HASH_BASE_H_
  
  #include "../common/platform.h"
  
  /* kHashMul32 multiplier has these properties:
     * The multiplier must be odd. Otherwise we may lose the highest bit.
     * No long streaks of ones or zeros.
     * There is no effort to ensure that it is a prime, the oddity is enough
       for this use.
     * The number has been tuned heuristically against compression benchmarks. */
  static const uint32_t kHashMul32 = 0x1E35A7BD;
  static const uint64_t kHashMul64 =
      BROTLI_MAKE_UINT64_T(0x1FE35A7Bu, 0xD3579BD3u);
  
  static BROTLI_INLINE uint32_t Hash14(const uint8_t* data) {
    uint32_t h = BROTLI_UNALIGNED_LOAD32LE(data) * kHashMul32;
    /* The higher bits contain more mixture from the multiplication,
       so we take our results from there. */
    return h >> (32 - 14);
  }
  
  static BROTLI_INLINE uint32_t Hash15(const uint8_t* data) {
    uint32_t h = BROTLI_UNALIGNED_LOAD32LE(data) * kHashMul32;
    /* The higher bits contain more mixture from the multiplication,
       so we take our results from there. */
    return h >> (32 - 15);
  }
  
  #endif  // THIRD_PARTY_BROTLI_ENC_HASH_BASE_H_
  

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