hash_utils.h (1206B)
1 // 2 // Copyright 2018 The ANGLE Project Authors. All rights reserved. 3 // Use of this source code is governed by a BSD-style license that can be 4 // found in the LICENSE file. 5 // 6 // hash_utils.h: Hashing based helper functions. 7 8 #ifndef COMMON_HASHUTILS_H_ 9 #define COMMON_HASHUTILS_H_ 10 11 #include "common/debug.h" 12 #include "common/third_party/xxhash/xxhash.h" 13 14 namespace angle 15 { 16 // Computes a hash of "key". Any data passed to this function must be multiples of 17 // 4 bytes, since the PMurHash32 method can only operate increments of 4-byte words. 18 inline std::size_t ComputeGenericHash(const void *key, size_t keySize) 19 { 20 static constexpr unsigned int kSeed = 0xABCDEF98; 21 22 // We can't support "odd" alignments. ComputeGenericHash requires aligned types 23 ASSERT(keySize % 4 == 0); 24 #if defined(ANGLE_IS_64_BIT_CPU) 25 return XXH64(key, keySize, kSeed); 26 #else 27 return XXH32(key, keySize, kSeed); 28 #endif // defined(ANGLE_IS_64_BIT_CPU) 29 } 30 31 template <typename T> 32 std::size_t ComputeGenericHash(const T &key) 33 { 34 static_assert(sizeof(key) % 4 == 0, "ComputeGenericHash requires aligned types"); 35 return ComputeGenericHash(&key, sizeof(key)); 36 } 37 } // namespace angle 38 39 #endif // COMMON_HASHUTILS_H_