beserved/server-1.2.6/readerWriter.c

21 bool initManagedData(bt_managed_data *data)
23 	data->readCount = 0;
24 	data->writeCount = 0;
26 	data->readCountVar = 0;
27 	data->writeCountVar = 0;
28 	data->readerQueueVar = 0;
29 	data->readerVar = 0;
30 	data->writerVar = 0;
32 	if ((data->readCountSem = create_sem(1, "Read Counter")) < 0)
35 	if ((data->writeCountSem = create_sem(1, "Write Counter")) < 0)
37 		delete_sem(data->readCountSem);
41 	if ((data->readerQueue = create_sem(1, "Read Queue")) < 0)
43 		delete_sem(data->writeCountSem);
44 		delete_sem(data->readCountSem);
48 	if ((data->reader = create_sem(1, "Single Reader")) < 0)
50 		delete_sem(data->readerQueue);
51 		delete_sem(data->writeCountSem);
52 		delete_sem(data->readCountSem);
56 	if ((data->writer = create_sem(1, "Writer")) < 0)
58 		delete_sem(data->reader);
59 		delete_sem(data->readerQueue);
60 		delete_sem(data->writeCountSem);
61 		delete_sem(data->readCountSem);
68 void closeManagedData(bt_managed_data *data)
70 	data->readCount = data->writeCount = 0;
72 	delete_sem(data->writer);
73 	delete_sem(data->reader);
74 	delete_sem(data->readerQueue);
75 	delete_sem(data->writeCountSem);
76 	delete_sem(data->readCountSem);
79 void beginReading(bt_managed_data *data)
81 	btLock(data->readerQueue, &data->readerQueueVar);
82 	btLock(data->reader, &data->readerVar);
83 	btLock(data->readCountSem, &data->readCountVar);
85 	data->readCount++;
86 	if (data->readCount == 1)
87 		btLock(data->writer, &data->writerVar);
89 	btUnlock(data->readCountSem, &data->readCountVar);
90 	btUnlock(data->reader, &data->readerVar);
91 	btUnlock(data->readerQueue, &data->readerQueueVar);
94 void endReading(bt_managed_data *data)
96 	btLock(data->readCountSem, &data->readCountVar);
98 	data->readCount--;
99 	if (data->readCount == 0)
100 		btUnlock(data->writer, &data->writerVar);
102 	btUnlock(data->readCountSem, &data->readCountVar);
105 void beginWriting(bt_managed_data *data)
107 	btLock(data->writeCountSem, &data->writeCountVar);
109 	data->writeCount++;
110 	if (data->writeCount == 1)
111 		btLock(data->reader, &data->readerVar);
113 	btUnlock(data->writeCountSem, &data->writeCountVar);
114 	btLock(data->writer, &data->writerVar);
117 void endWriting(bt_managed_data *data)
119 	btUnlock(data->writer, &data->writerVar);
120 	btLock(data->writeCountSem, &data->writeCountVar);
122 	data->writeCount--;
123 	if (data->writeCount == 0)
124 		btUnlock(data->reader, &data->readerVar);
126 	btUnlock(data->writeCountSem, &data->writeCountVar);