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Diffstat (limited to 'libs/rs/rsLocklessFifo.h')
-rw-r--r-- | libs/rs/rsLocklessFifo.h | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/libs/rs/rsLocklessFifo.h b/libs/rs/rsLocklessFifo.h new file mode 100644 index 0000000..ddef382 --- /dev/null +++ b/libs/rs/rsLocklessFifo.h @@ -0,0 +1,74 @@ +/* + * 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 <stdint.h> +#include <sys/types.h> +#include <stdlib.h> +#include <pthread.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: + uint8_t * volatile mPut; + uint8_t * volatile mGet; + uint8_t * mBuffer; + uint8_t * mEnd; + uint8_t mSize; + + pthread_mutex_t mMutex; + pthread_cond_t mCondition; + +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 |