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//
// Copyright 2018 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// hash_utils.h: Hashing based helper functions.
#ifndef COMMON_HASHUTILS_H_
#define COMMON_HASHUTILS_H_
#include "common/debug.h"
#include "common/third_party/xxhash/xxhash.h"
namespace angle
{
// Computes a hash of "key". Any data passed to this function must be multiples of
// 4 bytes, since the PMurHash32 method can only operate increments of 4-byte words.
inline std::size_t ComputeGenericHash(const void *key, size_t keySize)
{
static constexpr unsigned int kSeed = 0xABCDEF98;
// We can't support "odd" alignments. ComputeGenericHash requires aligned types
ASSERT(keySize % 4 == 0);
#if defined(ANGLE_IS_64_BIT_CPU)
return XXH64(key, keySize, kSeed);
#else
return XXH32(key, keySize, kSeed);
#endif // defined(ANGLE_IS_64_BIT_CPU)
}
template <typename T>
std::size_t ComputeGenericHash(const T &key)
{
static_assert(sizeof(key) % 4 == 0, "ComputeGenericHash requires aligned types");
return ComputeGenericHash(&key, sizeof(key));
}
} // namespace angle
#endif // COMMON_HASHUTILS_H_