96 lines
2.7 KiB
C++
96 lines
2.7 KiB
C++
/*
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* Copyright 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef NATIVEOBOE_FIFOCONTROLLERBASE_H
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#define NATIVEOBOE_FIFOCONTROLLERBASE_H
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#include <stdint.h>
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#include <sys/types.h>
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namespace oboe {
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/**
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* Manage the read/write indices of a circular buffer.
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*
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* The caller is responsible for reading and writing the actual data.
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* Note that the span of available frames may not be contiguous. They
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* may wrap around from the end to the beginning of the buffer. In that
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* case the data must be read or written in at least two blocks of frames.
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*
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*/
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class FifoControllerBase {
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public:
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/**
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* Constructor for FifoControllerBase
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* @param numFrames Size of the circular buffer in frames. Must be a power of 2.
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*/
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FifoControllerBase(uint32_t totalFrames, uint32_t threshold);
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virtual ~FifoControllerBase();
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/**
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* This may be negative if an unthrottled reader has read beyond the available data.
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* @return number of valid frames available to read. Never read more than this.
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*/
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int32_t getFullFramesAvailable();
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/**
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* The index in a circular buffer of the next frame to read.
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*/
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uint32_t getReadIndex();
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/**
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* @param numFrames number of frames to advance the read index
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*/
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void advanceReadIndex(int numFrames);
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/**
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* @return number of frames that can be written. Never write more than this.
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*/
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int32_t getEmptyFramesAvailable();
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/**
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* The index in a circular buffer of the next frame to write.
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*/
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uint32_t getWriteIndex();
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/**
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* @param numFrames number of frames to advance the write index
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*/
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void advanceWriteIndex(uint32_t numFrames);
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void setThreshold(uint32_t threshold);
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uint32_t getThreshold() const { return mThreshold; }
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uint32_t getFrameCapacity() const { return mTotalFrames; }
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virtual uint64_t getReadCounter() = 0;
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virtual void setReadCounter(uint64_t n) = 0;
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virtual uint64_t getWriteCounter() = 0;
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virtual void setWriteCounter(uint64_t n) = 0;
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private:
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uint32_t mTotalFrames;
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uint32_t mThreshold;
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};
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} // namespace oboe
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#endif //NATIVEOBOE_FIFOCONTROLLERBASE_H
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