1 /*
2  * Copyright (C) 2017 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 RING_BUFFER_H_
18 
19 #define RING_BUFFER_H_
20 
21 #include <media/stagefright/foundation/ABase.h>
22 
23 #include <hardware/sensors.h>
24 #include <utils/threads.h>
25 
26 namespace android {
27 
28 class RingBuffer {
29 public:
30     explicit RingBuffer(size_t size);
31     ~RingBuffer();
32 
33     ssize_t write(const sensors_event_t *ev, size_t size);
34     ssize_t read(sensors_event_t *ev, size_t size);
35 
36 private:
37     Mutex mLock;
38     Condition mNotEmptyCondition;
39 
40     size_t mSize;
41     sensors_event_t *mData;
42     size_t mReadPos, mWritePos;
43 
44     DISALLOW_EVIL_CONSTRUCTORS(RingBuffer);
45 };
46 
47 }  // namespace android
48 
49 #endif  // RING_BUFFER_H_
50