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