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/*
* Copyright 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef NATIVEOBOE_FIFOCONTROLLERBASE_H
#define NATIVEOBOE_FIFOCONTROLLERBASE_H
#include <stdint.h>
namespace oboe {
/**
* Manage the read/write indices of a circular buffer.
*
* The caller is responsible for reading and writing the actual data.
* Note that the span of available frames may not be contiguous. They
* may wrap around from the end to the beginning of the buffer. In that
* case the data must be read or written in at least two blocks of frames.
*
*/
class FifoControllerBase {
public:
/**
* @param totalFrames capacity of the circular buffer in frames.
*/
FifoControllerBase(uint32_t totalFrames);
virtual ~FifoControllerBase() = default;
/**
* The frames available to read will be calculated from the read and write counters.
* The result will be clipped to the capacity of the buffer.
* If the buffer has underflowed then this will return zero.
* @return number of valid frames available to read.
*/
uint32_t getFullFramesAvailable() const;
/**
* The index in a circular buffer of the next frame to read.
*/
uint32_t getReadIndex() const;
/**
* @param numFrames number of frames to advance the read index
*/
void advanceReadIndex(uint32_t numFrames);
/**
* @return maximum number of frames that can be written without exceeding the threshold.
*/
uint32_t getEmptyFramesAvailable() const;
/**
* The index in a circular buffer of the next frame to write.
*/
uint32_t getWriteIndex() const;
/**
* @param numFrames number of frames to advance the write index
*/
void advanceWriteIndex(uint32_t numFrames);
uint32_t getFrameCapacity() const { return mTotalFrames; }
virtual uint64_t getReadCounter() const = 0;
virtual void setReadCounter(uint64_t n) = 0;
virtual void incrementReadCounter(uint64_t n) = 0;
virtual uint64_t getWriteCounter() const = 0;
virtual void setWriteCounter(uint64_t n) = 0;
virtual void incrementWriteCounter(uint64_t n) = 0;
private:
uint32_t mTotalFrames;
};
} // namespace oboe
#endif //NATIVEOBOE_FIFOCONTROLLERBASE_H
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