1 /* 2 * Copyright (C) 2009 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_RS_LOCKLESS_FIFO_H 18 #define ANDROID_RS_LOCKLESS_FIFO_H 19 20 21 #include "rsUtils.h" 22 23 namespace android { 24 25 26 // A simple FIFO to be used as a producer / consumer between two 27 // threads. One is writer and one is reader. The common cases 28 // will not require locking. It is not threadsafe for multiple 29 // readers or writers by design. 30 31 class LocklessCommandFifo 32 { 33 public: 34 bool init(uint32_t size); 35 void shutdown(); 36 37 LocklessCommandFifo(); 38 ~LocklessCommandFifo(); 39 40 41 protected: 42 class Signal { 43 public: 44 Signal(); 45 ~Signal(); 46 47 bool init(); 48 49 void set(); 50 void wait(); 51 52 protected: 53 bool mSet; 54 pthread_mutex_t mMutex; 55 pthread_cond_t mCondition; 56 }; 57 58 uint8_t * volatile mPut; 59 uint8_t * volatile mGet; 60 uint8_t * mBuffer; 61 uint8_t * mEnd; 62 uint8_t mSize; 63 bool mInShutdown; 64 65 Signal mSignalToWorker; 66 Signal mSignalToControl; 67 68 69 70 public: 71 void * reserve(uint32_t bytes); 72 void commit(uint32_t command, uint32_t bytes); 73 void commitSync(uint32_t command, uint32_t bytes); 74 75 void flush(); 76 const void * get(uint32_t *command, uint32_t *bytesData); 77 void next(); 78 79 void makeSpace(uint32_t bytes); 80 81 bool isEmpty() const; 82 uint32_t getFreeSpace() const; 83 84 85 private: 86 void dumpState(const char *) const; 87 }; 88 89 90 } 91 #endif 92
