extern int threadPoolInitialize(int n) {
if (threadPool != NULL) {
return 0;
}
if (n < 1) {
return -1;
}
Thread* threads = (Thread*) malloc(n * sizeof(Thread));
int maxLength = QUEUE_MAX_SIZE;
size_t queueSize = maxLength * sizeof(ThreadPoolTask);
ThreadPoolTask** queue = (ThreadPoolTask**) malloc(queueSize);
threadPool = (ThreadPool*) malloc(sizeof(ThreadPool));
threadPool->terminated = 0;
threadPool->threads = threads;
threadPool->threadsLen = n;
threadPool->queue.data = queue;
threadPool->queue.length = 0;
threadPool->queue.maxLength = maxLength;
threadPool->queue.current = 0;
threadPool->queue.last = 0;
threadPool->queue.full = 0;
semaphoreCreate(&(threadPool->queue.mutex), 1);
semaphoreCreate(&(threadPool->queue.wait), 0);
semaphoreCreate(&(threadPool->queue.submit), 0);
int i;
for (i = 0; i < n; ++i) {
threadCreate(&(threads[i]), worker, NULL);
}
return 0;
}
static ThreadPoolTask* sumbit(void* (*routine)(void*), void* param, int toFront) {
if (threadPool == NULL) {
routine(param);
return NULL;
}
ThreadPoolQueue* queue = &(threadPool->queue);
semaphoreWait(&(queue->mutex));
if (threadPool->terminated) {
semaphorePost(&(queue->mutex));
return NULL;
}
if (queue->current == (queue->last + 1) % queue->maxLength) {
queue->full = 1;
semaphorePost(&(queue->mutex));
semaphoreWait(&(queue->wait));
semaphoreWait(&(queue->mutex));
}
if (threadPool->terminated) {
semaphorePost(&(queue->mutex));
return NULL;
}
ThreadPoolTask* task = (ThreadPoolTask*) malloc(sizeof(ThreadPoolTask));
task->routine = routine;
task->param = param;
semaphoreCreate(&(task->wait), 0);
if (toFront) {
queue->current = (queue->current - 1 + queue->maxLength) % queue->maxLength;
queue->data[queue->current] = task;
} else {
queue->data[queue->last] = task;
queue->last = (queue->last + 1) % queue->maxLength;
}
semaphorePost(&(queue->mutex));
semaphorePost(&(queue->submit));
return task;
}
Flag flagCreate(void)
{
return (Flag) semaphoreCreate(1);
}