1/*
2 * Copyright 2015 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 FIFO_FIFO_CONTROLLER_H
18#define FIFO_FIFO_CONTROLLER_H
19
20#include <stdint.h>
21#include <atomic>
22
23#include "FifoControllerBase.h"
24
25namespace android {
26
27/**
28 * A FIFO with counters contained in the class.
29 */
30class FifoController : public FifoControllerBase
31{
32public:
33    FifoController(fifo_counter_t bufferSize, fifo_counter_t threshold)
34    : FifoControllerBase(bufferSize, threshold)
35    , mReadCounter(0)
36    , mWriteCounter(0)
37    {}
38
39    virtual ~FifoController() {}
40
41    // TODO review use of memory barriers, probably incorrect
42    virtual fifo_counter_t getReadCounter() override {
43        return mReadCounter.load(std::memory_order_acquire);
44    }
45    virtual void setReadCounter(fifo_counter_t n) override {
46        mReadCounter.store(n, std::memory_order_release);
47    }
48    virtual fifo_counter_t getWriteCounter() override {
49        return mWriteCounter.load(std::memory_order_acquire);
50    }
51    virtual void setWriteCounter(fifo_counter_t n) override {
52        mWriteCounter.store(n, std::memory_order_release);
53    }
54
55private:
56    std::atomic<fifo_counter_t> mReadCounter;
57    std::atomic<fifo_counter_t> mWriteCounter;
58};
59
60}  // android
61
62#endif //FIFO_FIFO_CONTROLLER_H
63