1  //===-- sanitizer_common.h --------------------------------------*- C++ -*-===//
       2  //
       3  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
       4  // See https://llvm.org/LICENSE.txt for license information.
       5  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
       6  //
       7  //===----------------------------------------------------------------------===//
       8  //
       9  // This file implements a simple hash function.
      10  //===----------------------------------------------------------------------===//
      11  
      12  #ifndef SANITIZER_HASH_H
      13  #define SANITIZER_HASH_H
      14  
      15  #include "sanitizer_internal_defs.h"
      16  
      17  namespace __sanitizer {
      18  class MurMur2HashBuilder {
      19    static const u32 m = 0x5bd1e995;
      20    static const u32 seed = 0x9747b28c;
      21    static const u32 r = 24;
      22    u32 h;
      23  
      24   public:
      25    explicit MurMur2HashBuilder(u32 init = 0) { h = seed ^ init; }
      26    void add(u32 k) {
      27      k *= m;
      28      k ^= k >> r;
      29      k *= m;
      30      h *= m;
      31      h ^= k;
      32    }
      33    u32 get() {
      34      u32 x = h;
      35      x ^= x >> 13;
      36      x *= m;
      37      x ^= x >> 15;
      38      return x;
      39    }
      40  };
      41  
      42  class MurMur2Hash64Builder {
      43    static const u64 m = 0xc6a4a7935bd1e995ull;
      44    static const u64 seed = 0x9747b28c9747b28cull;
      45    static const u64 r = 47;
      46    u64 h;
      47  
      48   public:
      49    explicit MurMur2Hash64Builder(u64 init = 0) { h = seed ^ (init * m); }
      50    void add(u64 k) {
      51      k *= m;
      52      k ^= k >> r;
      53      k *= m;
      54      h ^= k;
      55      h *= m;
      56    }
      57    u64 get() {
      58      u64 x = h;
      59      x ^= x >> r;
      60      x *= m;
      61      x ^= x >> r;
      62      return x;
      63    }
      64  };
      65  }  //namespace __sanitizer
      66  
      67  #endif  // SANITIZER_HASH_H