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 <stdint.h>
22#include <cutils/ashmem.h>
23#include <sys/mman.h>
24
25#include "fifo/FifoBuffer.h"
26#include "binding/RingBufferParcelable.h"
27#include "binding/AudioEndpointParcelable.h"
28
29namespace aaudio {
30
31// Determine the placement of the counters and data in shared memory.
32#define SHARED_RINGBUFFER_READ_OFFSET   0
33#define SHARED_RINGBUFFER_WRITE_OFFSET  sizeof(fifo_counter_t)
34#define SHARED_RINGBUFFER_DATA_OFFSET   (SHARED_RINGBUFFER_WRITE_OFFSET + sizeof(fifo_counter_t))
35
36/**
37 * Atomic FIFO that uses shared memory.
38 */
39class SharedRingBuffer {
40public:
41    SharedRingBuffer() {}
42
43    virtual ~SharedRingBuffer();
44
45    aaudio_result_t allocate(android::fifo_frames_t bytesPerFrame, android::fifo_frames_t capacityInFrames);
46
47    void fillParcelable(AudioEndpointParcelable &endpointParcelable,
48                        RingBufferParcelable &ringBufferParcelable);
49
50    android::FifoBuffer * getFifoBuffer() {
51        return mFifoBuffer;
52    }
53
54private:
55    android::base::unique_fd  mFileDescriptor;
56    android::FifoBuffer      *mFifoBuffer = nullptr;
57    uint8_t                  *mSharedMemory = nullptr;
58    int32_t                   mSharedMemorySizeInBytes = 0;
59    int32_t                   mDataMemorySizeInBytes = 0;
60    android::fifo_frames_t    mCapacityInFrames = 0;
61};
62
63} /* namespace aaudio */
64
65#endif //AAUDIO_SHARED_RINGBUFFER_H
66