libsanitizer/sanitizer_common/sanitizer_hash.h

//===-- sanitizer_common.h --------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements a simple hash function.
//===----------------------------------------------------------------------===//

#ifndef SANITIZER_HASH_H
#define SANITIZER_HASH_H

#include "sanitizer_internal_defs.h"

namespace __sanitizer {
class MurMur2HashBuilder {
  static const u32 m = 0x5bd1e995;
  static const u32 seed = 0x9747b28c;
  static const u32 r = 24;
  u32 h;

 public:
  explicit MurMur2HashBuilder(u32 init = 0) { h = seed ^ init; }
  void add(u32 k) {
    k *= m;
    k ^= k >> r;
    k *= m;
    h *= m;
    h ^= k;
  }
  u32 get() {
    u32 x = h;
    x ^= x >> 13;
    x *= m;
    x ^= x >> 15;
    return x;
  }
};

class MurMur2Hash64Builder {
  static const u64 m = 0xc6a4a7935bd1e995ull;
  static const u64 seed = 0x9747b28c9747b28cull;
  static const u64 r = 47;
  u64 h;

 public:
  explicit MurMur2Hash64Builder(u64 init = 0) { h = seed ^ (init * m); }
  void add(u64 k) {
    k *= m;
    k ^= k >> r;
    k *= m;
    h ^= k;
    h *= m;
  }
  u64 get() {
    u64 x = h;
    x ^= x >> r;
    x *= m;
    x ^= x >> r;
    return x;
  }
};
}  //namespace __sanitizer

#endif  // SANITIZER_HASH_H