1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef MINIKIN_HASHER_H 18 #define MINIKIN_HASHER_H 19 20 #include <cstdint> 21 22 #include <string> 23 24 #include "minikin/Macros.h" 25 26 namespace minikin { 27 28 // Provides a Jenkins hash implementation. 29 class Hasher { 30 public: Hasher()31 Hasher() : mHash(0u) {} 32 update(uint32_t data)33 IGNORE_INTEGER_OVERFLOW inline Hasher& update(uint32_t data) { 34 mHash += data; 35 mHash += (mHash << 10); 36 mHash ^= (mHash >> 6); 37 return *this; 38 } 39 update(int32_t data)40 inline Hasher& update(int32_t data) { 41 update(static_cast<uint32_t>(data)); 42 return *this; 43 } 44 update(uint64_t data)45 inline Hasher& update(uint64_t data) { 46 update(static_cast<uint32_t>(data)); 47 update(static_cast<uint32_t>(data >> 32)); 48 return *this; 49 } 50 update(float data)51 inline Hasher& update(float data) { 52 union { 53 float f; 54 uint32_t i; 55 } bits; 56 bits.f = data; 57 return update(bits.i); 58 } 59 updateShorts(const uint16_t * data,uint32_t length)60 inline Hasher& updateShorts(const uint16_t* data, uint32_t length) { 61 update(length); 62 uint32_t i; 63 for (i = 0; i < (length & -2); i += 2) { 64 update((uint32_t)data[i] | ((uint32_t)data[i + 1] << 16)); 65 } 66 if (length & 1) { 67 update((uint32_t)data[i]); 68 } 69 return *this; 70 } 71 updateString(const std::string & str)72 inline Hasher& updateString(const std::string& str) { 73 uint32_t size = str.size(); 74 update(size); 75 uint32_t i; 76 for (i = 0; i < (size & -4); i += 4) { 77 update((uint32_t)str[i] | ((uint32_t)str[i + 1] << 8) | ((uint32_t)str[i + 2] << 16) | 78 ((uint32_t)str[i + 3] << 24)); 79 } 80 if (size & 3) { 81 uint32_t data = str[i]; 82 data |= ((size & 3) > 1) ? ((uint32_t)str[i + 1] << 8) : 0; 83 data |= ((size & 3) > 2) ? ((uint32_t)str[i + 2] << 16) : 0; 84 update(data); 85 } 86 return *this; 87 } 88 hash()89 IGNORE_INTEGER_OVERFLOW inline uint32_t hash() { 90 uint32_t hash = mHash; 91 hash += (hash << 3); 92 hash ^= (hash >> 11); 93 hash += (hash << 15); 94 return hash; 95 } 96 97 private: 98 uint32_t mHash; 99 }; 100 101 } // namespace minikin 102 103 #endif // MINIKIN_HASHER_H 104