1 /* 2 * Copyright (c) 2021-2022 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 #ifndef HIPERF_RING_BUFFER_H 16 #define HIPERF_RING_BUFFER_H 17 #include <memory> 18 19 namespace OHOS { 20 namespace Developtools { 21 namespace HiPerf { 22 class RingBuffer { 23 public: 24 // little endian, perf_event_header.type is less than 0xff, so set it 25 static constexpr uint8_t MARGIN_BYTE = 0xFF; 26 27 explicit RingBuffer(size_t size); 28 ~RingBuffer(); 29 // get size of the writable space 30 size_t GetFreeSize() const; 31 32 // before writing data to rbuff, alloc space first 33 uint8_t *AllocForWrite(size_t writeSize); 34 // after writing data, move head pointer 35 void EndWrite(); 36 // get data from buff, return nullptr if no readable data 37 uint8_t *GetReadData(); 38 // after reading, move tail pointer 39 void EndRead(); 40 41 private: 42 std::unique_ptr<uint8_t[]> buf_ = nullptr; 43 const size_t size_; 44 std::atomic_size_t head_ = 0; // write after this, always increase 45 std::atomic_size_t tail_ = 0; // read from this, always increase 46 size_t writeSize_ = 0; 47 size_t readSize_ = 0; 48 }; 49 } // namespace HiPerf 50 } // namespace Developtools 51 } // namespace OHOS 52 #endif // HIPERF_RING_BUFFER_H 53