1 /* 2 * Copyright (c) 2022 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef COMMON_COMPONENTS_PLATFORM_STRING_HASH_COMMON_H 17 #define COMMON_COMPONENTS_PLATFORM_STRING_HASH_COMMON_H 18 19 #include <cstdint> 20 21 #include "common_components/base/config.h" 22 #include "common_components/platform/string_hash.h" 23 24 namespace common { 25 class StringHashInternal { 26 friend class StringHashHelper; 27 private: 28 template <typename T> ComputeHashForDataOfLongString(const T * data,size_t size,uint32_t hashSeed)29 static uint32_t ComputeHashForDataOfLongString(const T *data, size_t size, 30 uint32_t hashSeed) 31 { 32 constexpr uint32_t blockSize = StringHash::BLOCK_SIZE; 33 constexpr uint32_t scale = StringHash::BLOCK_MULTIPLY; 34 uint32_t hash[blockSize] = {}; 35 uint32_t index = 0; 36 uint32_t remainder = size & (blockSize - 1); 37 switch (remainder) { 38 #define CASE(N) case (N): \ 39 hash[blockSize - (N)] = data[index++] * StringHash::MULTIPLIER[blockSize - (N)]; [[fallthrough]] 40 CASE(StringHash::SIZE_3); 41 CASE(StringHash::SIZE_2); 42 CASE(StringHash::SIZE_1); 43 #undef CASE 44 default: 45 break; 46 } 47 hash[0] += hashSeed * StringHash::MULTIPLIER[blockSize - 1 - remainder]; 48 49 uint32_t dataMul[blockSize] = {}; 50 for (; index < size; index += blockSize) { 51 for (size_t i = 0; i < blockSize; i++) { 52 dataMul[i] = data[index + i] * StringHash::MULTIPLIER[i]; 53 hash[i] = hash[i] * scale + dataMul[i]; 54 } 55 } 56 uint32_t hashTotal = 0; 57 for (size_t i = 0; i < blockSize; i++) { 58 hashTotal += hash[i]; 59 } 60 return hashTotal; 61 } 62 }; 63 } // namespace common 64 #endif // COMMON_COMPONENTS_PLATFORM_STRING_HASH_COMMON_H