1 /* 2 * Copyright (C) 2019 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 CHRE_PLATFORM_ATOMIC_H_ 18 #define CHRE_PLATFORM_ATOMIC_H_ 19 20 #include "chre/target_platform/atomic_base.h" 21 #include "chre/util/non_copyable.h" 22 23 namespace chre { 24 25 /** 26 * Provides an implementation of an atomic boolean. AtomicBoolBase is 27 * subclassed here to allow platforms to use their own underlying atomic APIs. 28 */ 29 class AtomicBool : public AtomicBoolBase, 30 public NonCopyable { 31 public: 32 /** 33 * Allows the platform to do any atomic initialization at construction time. 34 * 35 * @param The starting value for the object. 36 */ 37 AtomicBool(bool startingValue); 38 39 /** 40 * Atomically assigns the desired value to the atomic object. Equivalent to 41 * store(). 42 * 43 * @param The value the object will be replaced with. 44 * 45 * @return The desired value. 46 */ 47 bool operator=(bool desired); 48 49 /** 50 * Atomically loads the current value of the atomic object. Equivalent to 51 * load(). 52 * 53 * @return The current value of the object. 54 */ 55 operator bool() const { 56 return load(); 57 }; 58 59 /** 60 * Atomically loads the current value of the atomic object. 61 * 62 * @return The current value of the object. 63 */ 64 bool load() const; 65 66 /** 67 * Atomically replaces the current value of the atomic object. 68 * 69 * @param The value the object will be replaced with. 70 */ 71 void store(bool desired); 72 73 /** 74 * Atomically replaces the value of the atomic object. 75 * 76 * @param The value the object should have when the method returns. 77 * 78 * @return The previous value of the object. 79 */ 80 bool exchange(bool desired); 81 }; 82 83 /** 84 * Provides an implementation of an atomic uint32_t. AtomicUint32Base is 85 * subclassed here to allow platforms to use their own underlying atomic APIs. 86 */ 87 class AtomicUint32 : public AtomicUint32Base, 88 public NonCopyable { 89 public: 90 /** 91 * Allows the platform to do any atomic initialization at construction time. 92 * 93 * @param The starting value for the object. 94 */ 95 AtomicUint32(uint32_t startingValue); 96 97 /** 98 * Atomically assigns the desired value to the atomic object. Equivalent to 99 * store(). 100 * 101 * @param The value the object will be replaced with. 102 * 103 * @return The desired value. 104 */ 105 uint32_t operator=(uint32_t desired); 106 107 /** 108 * Atomically loads the current value of the atomic object. Equivalent to 109 * load(). 110 * 111 * @return The current value of the object. 112 */ uint32_t()113 operator uint32_t() const { 114 return load(); 115 } 116 117 /** 118 * Atomically loads the current value of the atomic object. 119 * 120 * @return The current value of the object. 121 */ 122 uint32_t load() const; 123 124 /** 125 * Atomically replaces the current value of the atomic object. 126 * 127 * @param The value the object will be replaced with. 128 */ 129 void store(uint32_t desired); 130 131 /** 132 * Atomically replaces the value of the atomic object. 133 * 134 * @param The value the object should have when the method returns. 135 * 136 * @return The previous value of the object. 137 */ 138 uint32_t exchange(uint32_t desired); 139 140 /** 141 * Atomically adds the argument to the current value of the object. 142 * 143 * @param The amount which the object should be increased by. 144 * 145 * @return The previous value of the object. 146 */ 147 uint32_t fetch_add(uint32_t arg); 148 149 /** 150 * Atomically increments the value stored in the atomic object by 1. 151 * 152 * @return The previous value of the object. 153 */ 154 uint32_t fetch_increment(); 155 156 /** 157 * Atomically subtracts the argument from the current value of the object. 158 * 159 * @param The amount which the object should be decreased by. 160 * 161 * @return The previous value of the object. 162 */ 163 uint32_t fetch_sub(uint32_t arg); 164 165 /** 166 * Atomically decrements the value stored in the atomic object by 1. 167 * 168 * @return The previous value of the object. 169 */ 170 uint32_t fetch_decrement(); 171 }; 172 173 } // namespace chre 174 175 #include "chre/target_platform/atomic_base_impl.h" 176 177 #endif // CHRE_PLATFORM_ATOMIC_H_ 178