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Diffstat (limited to 'src/stable/synchroqueue.h')
| -rw-r--r-- | src/stable/synchroqueue.h | 240 |
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diff --git a/src/stable/synchroqueue.h b/src/stable/synchroqueue.h new file mode 100644 index 0000000..79d5e49 --- /dev/null +++ b/src/stable/synchroqueue.h | |||
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| 1 | /* | ||
| 2 | * Copyright (C) 2007-2011 Xagasoft, All rights reserved. | ||
| 3 | * | ||
| 4 | * This file is part of the libbu++ library and is released under the | ||
| 5 | * terms of the license contained in the file LICENSE. | ||
| 6 | */ | ||
| 7 | |||
| 8 | #ifndef BU_SYNCHRO_QUEUE_H | ||
| 9 | #define BU_SYNCHRO_QUEUE_H | ||
| 10 | |||
| 11 | #include <pthread.h> | ||
| 12 | |||
| 13 | #include "bu/mutex.h" | ||
| 14 | #include "bu/condition.h" | ||
| 15 | |||
| 16 | namespace Bu | ||
| 17 | { | ||
| 18 | /** | ||
| 19 | * A thread-safe queue class. This class is a very simple queue with some | ||
| 20 | * cool extra functionality for use with the Synchro system. The main extra | ||
| 21 | * that it provides is the option to either dequeue without blocking, with | ||
| 22 | * infinite blocking, or with timed blocking, which will return a value if | ||
| 23 | * something is enqueued within the specified time limit, or NULL if the | ||
| 24 | * time limit is exceded. | ||
| 25 | *@ingroup Threading Containers | ||
| 26 | */ | ||
| 27 | template <class T> | ||
| 28 | class SynchroQueue | ||
| 29 | { | ||
| 30 | private: | ||
| 31 | /** | ||
| 32 | * Helper struct. Keeps track of linked-list items for the queue data. | ||
| 33 | */ | ||
| 34 | typedef struct Item | ||
| 35 | { | ||
| 36 | T pData; | ||
| 37 | Item *pNext; | ||
| 38 | } Item; | ||
| 39 | |||
| 40 | public: | ||
| 41 | /** | ||
| 42 | * Construct an empty queue. | ||
| 43 | */ | ||
| 44 | SynchroQueue() : | ||
| 45 | pStart( NULL ), | ||
| 46 | pEnd( NULL ), | ||
| 47 | nSize( 0 ) | ||
| 48 | { | ||
| 49 | } | ||
| 50 | |||
| 51 | /** | ||
| 52 | * Destroy the queue. This function will simply free all contained | ||
| 53 | * structures. If you stored pointers in the queue, this will lose the | ||
| 54 | * pointers without cleaning up the memory they pointed to. Make sure | ||
| 55 | * you're queue is empty before allowing it to be destroyed! | ||
| 56 | */ | ||
| 57 | ~SynchroQueue() | ||
| 58 | { | ||
| 59 | Item *pCur = pStart; | ||
| 60 | while( pCur ) | ||
| 61 | { | ||
| 62 | Item *pTmp = pCur->pNext; | ||
| 63 | delete pCur; | ||
| 64 | pCur = pTmp; | ||
| 65 | } | ||
| 66 | } | ||
| 67 | |||
| 68 | /** | ||
| 69 | * Enqueue a pieces of data. The new data will go at the end of the | ||
| 70 | * queue, and unless another piece of data is enqueued, will be the | ||
| 71 | * last piece of data to be dequeued. | ||
| 72 | *@param pData The data to enqueue. If this is not a primitive data | ||
| 73 | * type it's probably best to use a pointer type. | ||
| 74 | */ | ||
| 75 | void enqueue( T pData ) | ||
| 76 | { | ||
| 77 | mOperate.lock(); | ||
| 78 | |||
| 79 | if( pStart == NULL ) | ||
| 80 | { | ||
| 81 | pStart = pEnd = new Item; | ||
| 82 | pStart->pData = pData; | ||
| 83 | pStart->pNext = NULL; | ||
| 84 | nSize++; | ||
| 85 | } | ||
| 86 | else | ||
| 87 | { | ||
| 88 | pEnd->pNext = new Item; | ||
| 89 | pEnd = pEnd->pNext; | ||
| 90 | pEnd->pData = pData; | ||
| 91 | pEnd->pNext = NULL; | ||
| 92 | nSize++; | ||
| 93 | } | ||
| 94 | |||
| 95 | cBlock.signal(); | ||
| 96 | |||
| 97 | mOperate.unlock(); | ||
| 98 | } | ||
| 99 | |||
| 100 | /** | ||
| 101 | * Dequeue the first item from the queue. This function can operate in | ||
| 102 | * two different modes, blocking and non-blocking. In non-blocking | ||
| 103 | * mode it will return immediately weather there was data in the queue | ||
| 104 | * or not. If there was data it will remove it from the queue and | ||
| 105 | * return it to the caller. | ||
| 106 | * | ||
| 107 | * In blocking mode it will block forever wating for data to be | ||
| 108 | * enqueued. When data finally is enqueued this function will return | ||
| 109 | * immediately with the new data. The only way this function should | ||
| 110 | * ever return a null in blocking mode is if the calling thread was | ||
| 111 | * cancelled. It's probably a good idea to check for NULL return | ||
| 112 | * values even if you use blocking, just to be on the safe side. | ||
| 113 | *@param bBlock Set to true to enable blocking, leave as false to work | ||
| 114 | * in non-blocking mode. | ||
| 115 | *@returns The next piece of data in the queue, or NULL if no data was | ||
| 116 | * in the queue. | ||
| 117 | */ | ||
| 118 | T dequeue( bool bBlock=false ) | ||
| 119 | { | ||
| 120 | mOperate.lock(); | ||
| 121 | if( pStart == NULL ) | ||
| 122 | { | ||
| 123 | mOperate.unlock(); | ||
| 124 | |||
| 125 | if( bBlock ) | ||
| 126 | { | ||
| 127 | cBlock.lock(); | ||
| 128 | |||
| 129 | while( pStart == NULL ) | ||
| 130 | cBlock.wait(); | ||
| 131 | |||
| 132 | T tmp = dequeue( false ); | ||
| 133 | |||
| 134 | cBlock.unlock(); | ||
| 135 | return tmp; | ||
| 136 | |||
| 137 | } | ||
| 138 | |||
| 139 | return NULL; | ||
| 140 | } | ||
| 141 | else | ||
| 142 | { | ||
| 143 | T pTmp = pStart->pData; | ||
| 144 | Item *pDel = pStart; | ||
| 145 | pStart = pStart->pNext; | ||
| 146 | delete pDel; | ||
| 147 | nSize--; | ||
| 148 | |||
| 149 | mOperate.unlock(); | ||
| 150 | return pTmp; | ||
| 151 | } | ||
| 152 | } | ||
| 153 | |||
| 154 | /** | ||
| 155 | * Operates just like the other dequeue function in blocking mode with | ||
| 156 | * one twist. This function will block for at most nSec seconds and | ||
| 157 | * nUSec micro-seconds. If the timer is up and no data is available, | ||
| 158 | * this will just return NULL. If data is enqueued before the timeout | ||
| 159 | * expires, it will dequeue and exit immediately. | ||
| 160 | *@param nSec The number of seconds to wait, max. | ||
| 161 | *@param nUSec The number of micro-seconds to wait, max. | ||
| 162 | *@returns The next piece of data in the queue, or NULL if the timeout | ||
| 163 | * was exceeded. | ||
| 164 | */ | ||
| 165 | T dequeue( int nSec, int nUSec ) | ||
| 166 | { | ||
| 167 | mOperate.lock(); | ||
| 168 | if( pStart == NULL ) | ||
| 169 | { | ||
| 170 | mOperate.unlock(); | ||
| 171 | |||
| 172 | cBlock.lock(); | ||
| 173 | |||
| 174 | cBlock.wait( nSec, nUSec ); | ||
| 175 | |||
| 176 | if( pStart == NULL ) | ||
| 177 | { | ||
| 178 | cBlock.unlock(); | ||
| 179 | return NULL; | ||
| 180 | } | ||
| 181 | |||
| 182 | mOperate.lock(); | ||
| 183 | T pTmp = pStart->pData; | ||
| 184 | Item *pDel = pStart; | ||
| 185 | pStart = pStart->pNext; | ||
| 186 | delete pDel; | ||
| 187 | nSize--; | ||
| 188 | mOperate.unlock(); | ||
| 189 | |||
| 190 | cBlock.unlock(); | ||
| 191 | return pTmp; | ||
| 192 | } | ||
| 193 | else | ||
| 194 | { | ||
| 195 | T pTmp = pStart->pData; | ||
| 196 | Item *pDel = pStart; | ||
| 197 | pStart = pStart->pNext; | ||
| 198 | delete pDel; | ||
| 199 | nSize--; | ||
| 200 | |||
| 201 | mOperate.unlock(); | ||
| 202 | return pTmp; | ||
| 203 | } | ||
| 204 | } | ||
| 205 | |||
| 206 | /** | ||
| 207 | * Checks to see if the queue has data in it or not. Note that there | ||
| 208 | * is no function to determine the length of the queue. This data | ||
| 209 | * isn't kept track of. If you really need to know, fix this. | ||
| 210 | *@returns True if the queue is empty, false if it has data in it. | ||
| 211 | */ | ||
| 212 | bool isEmpty() | ||
| 213 | { | ||
| 214 | mOperate.lock(); | ||
| 215 | bool bEmpty = (pStart == NULL ); | ||
| 216 | mOperate.unlock(); | ||
| 217 | |||
| 218 | return bEmpty; | ||
| 219 | } | ||
| 220 | |||
| 221 | long getSize() | ||
| 222 | { | ||
| 223 | mOperate.lock(); | ||
| 224 | long nRet = nSize; | ||
| 225 | mOperate.unlock(); | ||
| 226 | |||
| 227 | return nRet; | ||
| 228 | } | ||
| 229 | |||
| 230 | private: | ||
| 231 | Item *pStart; /**< The start of the queue, the next element to dequeue. */ | ||
| 232 | Item *pEnd; /**< The end of the queue, the last element to dequeue. */ | ||
| 233 | long nSize; /**< The number of items in the queue. */ | ||
| 234 | |||
| 235 | Mutex mOperate; /**< The master mutex, used on all operations. */ | ||
| 236 | Condition cBlock; /**< The condition for blocking dequeues. */ | ||
| 237 | }; | ||
| 238 | } | ||
| 239 | |||
| 240 | #endif | ||
