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/*
* Copyright (C) 2009 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 ANDROID_RS_LOCKLESS_FIFO_H
#define ANDROID_RS_LOCKLESS_FIFO_H
#include "rsUtils.h"
namespace android {
// A simple FIFO to be used as a producer / consumer between two
// threads. One is writer and one is reader. The common cases
// will not require locking. It is not threadsafe for multiple
// readers or writers by design.
class LocklessCommandFifo
{
public:
bool init(uint32_t size);
LocklessCommandFifo();
~LocklessCommandFifo();
protected:
class Signal {
public:
Signal();
~Signal();
bool init();
void set();
void wait();
protected:
bool mSet;
pthread_mutex_t mMutex;
pthread_cond_t mCondition;
};
uint8_t * volatile mPut;
uint8_t * volatile mGet;
uint8_t * mBuffer;
uint8_t * mEnd;
uint8_t mSize;
Signal mSignalToWorker;
Signal mSignalToControl;
public:
void * reserve(uint32_t bytes);
void commit(uint32_t command, uint32_t bytes);
void commitSync(uint32_t command, uint32_t bytes);
void flush();
const void * get(uint32_t *command, uint32_t *bytesData);
void next();
void makeSpace(uint32_t bytes);
bool isEmpty() const;
uint32_t getFreeSpace() const;
private:
void dumpState(const char *) const;
};
}
#endif