1 /* 2 * Copyright (C) 2016 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 AAUDIO_SHARED_RINGBUFFER_H 18 #define AAUDIO_SHARED_RINGBUFFER_H 19 20 #include <stdint.h> 21 #include <cutils/ashmem.h> 22 #include <sys/mman.h> 23 24 #include "fifo/FifoBuffer.h" 25 #include "binding/RingBufferParcelable.h" 26 #include "binding/AudioEndpointParcelable.h" 27 28 namespace aaudio { 29 30 // Determine the placement of the counters and data in shared memory. 31 #define SHARED_RINGBUFFER_READ_OFFSET 0 32 #define SHARED_RINGBUFFER_WRITE_OFFSET sizeof(fifo_counter_t) 33 #define SHARED_RINGBUFFER_DATA_OFFSET (SHARED_RINGBUFFER_WRITE_OFFSET + sizeof(fifo_counter_t)) 34 35 /** 36 * Atomic FIFO that uses shared memory. 37 */ 38 class SharedRingBuffer { 39 public: SharedRingBuffer()40 SharedRingBuffer() {} 41 42 virtual ~SharedRingBuffer(); 43 44 aaudio_result_t allocate(android::fifo_frames_t bytesPerFrame, android::fifo_frames_t capacityInFrames); 45 46 void fillParcelable(AudioEndpointParcelable &endpointParcelable, 47 RingBufferParcelable &ringBufferParcelable); 48 getFifoBuffer()49 android::FifoBuffer * getFifoBuffer() { 50 return mFifoBuffer; 51 } 52 53 private: 54 int mFileDescriptor = -1; 55 android::FifoBuffer *mFifoBuffer = nullptr; 56 uint8_t *mSharedMemory = nullptr; 57 int32_t mSharedMemorySizeInBytes = 0; 58 int32_t mDataMemorySizeInBytes = 0; 59 android::fifo_frames_t mCapacityInFrames = 0; 60 }; 61 62 } /* namespace aaudio */ 63 64 #endif //AAUDIO_SHARED_RINGBUFFER_H 65