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


#define BUFFER_SIZE 16 // 缓冲区数量
#define OVER ( - 1)
struct prodcons buffer;

void init(struct prodcons *b);
void *producer(void *data);
void *consumer(void *data);
void put(struct prodcons *b, int data);
int get(struct prodcons *b);

struct prodcons
{
		// 缓冲区相关数据结构
		int buffer[BUFFER_SIZE]; /* 实际数据存放的数组*/
		pthread_mutex_t lock; /* 互斥体lock 用于对缓冲区的互斥操作 */
		int readpos, writepos; /* 读写指针*/
		pthread_cond_t notempty; /* 缓冲区非空的条件变量 */
		pthread_cond_t notfull; /* 缓冲区未满的条件变量 */
};


int main(void)
{
		pthread_t th_a, th_b;
		void *retval;
		init(&buffer);
		
		/* 创建生产者和消费者线程*/
		pthread_create(&th_a, NULL, producer, 0);
		pthread_create(&th_b, NULL, consumer, 0);
		/* 等待两个线程结束*/
		pthread_join(th_a, &retval);
		pthread_join(th_b, &retval);
		return 0;
}



/* 初始化缓冲区结构 */
void init(struct prodcons *b)
{
		pthread_mutex_init(&b->lock, NULL);
		pthread_cond_init(&b->notempty, NULL);
		pthread_cond_init(&b->notfull, NULL);
		b->readpos = 0;
		b->writepos = 0;
}

/***************************** 测试:生产者线程将1 到10000 的整数送入缓冲区,
*****************************消费者线程从缓冲区中获取整数,两者都打印信息**************************/

/************生产者************/
void *producer(void *data)
{
		int n;
		//for (n = 0; n < 10000; n++)
		for (n = 0; n < 10; n++)	
		{
			printf("%d --->\n", n);
			put(&buffer, n);
		} 
		put(&buffer, OVER);
		return NULL;
}

/************消费者************/
void *consumer(void *data)
{
		int d;
		while (1)
		{
			d = get(&buffer);
			if (d == OVER)
			break;
			printf("--->%d \n", d);
		}
	return NULL;
}


/**************=======put====将产品放入缓冲区,这里是存入一个整数********************/
void put(struct prodcons *b, int data)
{
		pthread_mutex_lock(&b->lock);
		/* 等待缓冲区未满*/
		if ((b->writepos + 1) % BUFFER_SIZE == b->readpos)
		{
				pthread_cond_wait(&b->notfull, &b->lock);
		}
		/* 写数据,并移动指针 */
		b->buffer[b->writepos] = data;
		b->writepos++;
		if (b->writepos >= BUFFER_SIZE)
		b->writepos = 0;
		/* 设置缓冲区非空的条件变量*/
		pthread_cond_signal(&b->notempty);
		pthread_mutex_unlock(&b->lock);
}

/*****************=======get====从缓冲区中取出整数*************************************/
int get(struct prodcons *b)
{
		int data;
		pthread_mutex_lock(&b->lock);
		/* 等待缓冲区非空*/
		if (b->writepos == b->readpos)
		{
		pthread_cond_wait(&b->notempty, &b->lock);
		}
		/* 读数据,移动读指针*/
		data = b->buffer[b->readpos];
		b->readpos++;
		if (b->readpos >= BUFFER_SIZE)
		b->readpos = 0;
		/* 设置缓冲区未满的条件变量*/
		pthread_cond_signal(&b->notfull);
		pthread_mutex_unlock(&b->lock);
		return data;
}