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 <android-base/unique_fd.h> 21 #include <cutils/ashmem.h> 22 #include <stdint.h> 23 #include <string> 24 #include <sys/mman.h> 25 26 #include "fifo/FifoBuffer.h" 27 #include "binding/RingBufferParcelable.h" 28 #include "binding/AudioEndpointParcelable.h" 29 30 namespace aaudio { 31 32 // Determine the placement of the counters and data in shared memory. 33 #define SHARED_RINGBUFFER_READ_OFFSET 0 34 #define SHARED_RINGBUFFER_WRITE_OFFSET sizeof(fifo_counter_t) 35 #define SHARED_RINGBUFFER_DATA_OFFSET (SHARED_RINGBUFFER_WRITE_OFFSET + sizeof(fifo_counter_t)) 36 37 /** 38 * Atomic FIFO that uses shared memory. 39 */ 40 class SharedRingBuffer { 41 public: SharedRingBuffer()42 SharedRingBuffer() {} 43 44 virtual ~SharedRingBuffer(); 45 46 aaudio_result_t allocate(android::fifo_frames_t bytesPerFrame, android::fifo_frames_t capacityInFrames); 47 48 void fillParcelable(AudioEndpointParcelable* endpointParcelable, 49 RingBufferParcelable &ringBufferParcelable); 50 51 /** 52 * Return available frames as a fraction of the capacity. 53 * @return fullness between 0.0 and 1.0 54 */ 55 double getFractionalFullness() const; 56 57 // dump: write# read# available 58 std::string dump() const; 59 getFifoBuffer()60 std::shared_ptr<android::FifoBuffer> getFifoBuffer() { 61 return mFifoBuffer; 62 } 63 64 private: 65 android::base::unique_fd mFileDescriptor; 66 std::shared_ptr<android::FifoBufferIndirect> mFifoBuffer; 67 uint8_t *mSharedMemory = nullptr; // mmap 68 int32_t mSharedMemorySizeInBytes = 0; 69 // size of memory used for data vs counters 70 int32_t mDataMemorySizeInBytes = 0; 71 android::fifo_frames_t mCapacityInFrames = 0; 72 }; 73 74 } /* namespace aaudio */ 75 76 #endif //AAUDIO_SHARED_RINGBUFFER_H 77