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1 /*
2  * Copyright (C) 2023 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 #pragma once
18 
19 #include <android-base/unique_fd.h>
20 #include <cutils/ashmem.h>
21 #include <stdint.h>
22 #include <string>
23 #include <sys/mman.h>
24 
25 #include "fifo/FifoBuffer.h"
26 #include "binding/RingBufferParcelable.h"
27 #include "binding/AudioEndpointParcelable.h"
28 
29 namespace aaudio {
30 
31 /**
32  * Wrap the shared memory with read and write counters. Provide a fifo buffer to access the
33  * wrapped shared memory.
34  */
35 class SharedMemoryWrapper {
36 public:
37     explicit SharedMemoryWrapper();
38 
39     virtual ~SharedMemoryWrapper();
40 
getDataFileDescriptor()41     android::base::unique_fd& getDataFileDescriptor() { return mDataFd; }
42 
43     aaudio_result_t setupFifoBuffer(android::fifo_frames_t bytesPerFrame,
44                                     android::fifo_frames_t capacityInFrames);
45 
46     void reset();
47 
48     enum CounterFilling {
49         NONE = 0,
50         READ = 1,
51         WRITE = 2,
52     };
53     /**
54      * Fill shared memory into parcelable.
55      *
56      * @param endpointParcelable container for ring buffers and shared memories
57      * @param ringBufferParcelable the ring buffer
58      * @param bytesPerFrame the bytes per frame of the data memory
59      * @param framesPerBurst the frame per burst of the data memory
60      * @param capacityInFrames the capacity in frames of the data memory
61      * @param counterFilling a bit mask to control if the counter from the wrapper should be filled
62      *                       or not.
63      */
64     void fillParcelable(AudioEndpointParcelable* endpointParcelable,
65                         RingBufferParcelable &ringBufferParcelable,
66                         int32_t bytesPerFrame,
67                         int32_t framesPerBurst,
68                         int32_t capacityInFrames,
69                         CounterFilling counterFilling = NONE);
70 
getFifoBuffer()71     std::shared_ptr<android::FifoBuffer> getFifoBuffer() {
72         return mFifoBuffer;
73     }
74 
75 private:
76     android::base::unique_fd mDataFd;
77     android::base::unique_fd mCounterFd;
78     uint8_t* mCounterMemoryAddress = nullptr;
79     android::fifo_counter_t* mReadCounterAddress = nullptr;
80     android::fifo_counter_t* mWriteCounterAddress = nullptr;
81     std::shared_ptr<android::FifoBufferIndirect> mFifoBuffer;
82     uint8_t* mSharedMemory = nullptr;
83     int32_t mSharedMemorySizeInBytes = 0;
84 };
85 
86 } /* namespace aaudio */
87