多线程线程队列的实现

转载

mb5fdb0a1b25659 2013-04-14 12:20:00

文章标签 i++ #include #define 条件变量测试方法 文章分类 代码人生

参考他人的方法，自己做了简单修改，实现一个通用的线程队列。

#include <stdio.h>
#include <pthread.h>
#include <unistd.h>

#define POOL_SIZE 10
#define QUEUE_LEN 20
pthread_mutex_t queue_lock; //队列锁
pthread_cond_t  queue_cond; //条件变量

int head = 0, tail = 0;
int queue[QUEUE_LEN];

void delay(int x)
{
  int i,j;
  for(i = 0; i < x; i++)
    for(j = 0; j <x; j++);
}

void fun1(){
  printf("fun1 start\n");
  delay(1000);
  printf("fun1 end\n");
}

void fun2(){
  printf("fun2 start\n");
  delay(2000);
  printf("fun2 end\n");
}

void fun3(){
  printf("fun3 start\n");
  delay(3000);
  printf("fun3 end\n");
}

void fun4(){
  printf("fun4 start\n");
  delay(4000);
  printf("fun4 end\n");
}

int dequeue()//出对列函数
{
  int y;
  pthread_mutex_lock(&queue_lock);
  while(head == tail)//队列中 无情求时，等待
  {
    pthread_cond_wait(&queue_cond, &queue_lock);//自动释放锁   
  }
  y = queue[++head];//需做循环处理  queue[head] is NULL
  if(head >= QUEUE_LEN)
    head = 0;
  pthread_mutex_unlock(&queue_lock);
  return y;
}

void * process_queue(void *arg)
{
  int x = 0;
  for(;;)
  {
    x = dequeue();
    printf("%d dequeue \n",x);
    switch(x)
    {
      case 1:
        fun1(); break;
      case 2:
        fun2(); break;
        case 3:
        fun3(); break;
      default:
        fun4(); break;
    }   
  }
}

int enqueue(int x)//插入请求 
{
  int next;
  pthread_mutex_lock(&queue_lock);
  next = tail + 1;
  if(next >= QUEUE_LEN)
    next = 0;
  if(next == head)
  {
   pthread_cond_signal(&queue_cond);//
   pthread_mutex_unlock(&queue_lock);   
   return 0;// 表示队列已满
  }
  queue[next] = x;
  tail = next;  
  pthread_cond_signal(&queue_cond);//激活
  pthread_mutex_unlock(&queue_lock);
  return 1;//入队成功   
}

int main()
{
  int i;
  int num = 0;
  pthread_t tid[POOL_SIZE];

  pthread_mutex_init(&queue_lock, NULL);
  pthread_cond_init(&queue_cond, NULL);

  for(i = 0; i < POOL_SIZE; i++)
    pthread_create(&tid[i], NULL, process_queue, NULL);

  while(1)
  {
    scanf("%d",&num);
    if(0 == num)
    //  break;
      return 0;
    printf("%d ",num);
    while(!enqueue(num))//队列满时 等待
    {
      printf("queue is full\n");
      sleep(1);
    }
  }

//  for(i = 0; i < POOL_SIZE; i++)
//    pthread_join(tid[i], NULL);

//  pthread_mutex_destory(&queue_lock);
//  pthread_cond_destroy(&queue_cond);

  return 0;
}