consumer模型

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>#define BUFFER_SIZE 8struct Products
{
int buffer[BUFFER_SIZE];
pthread_mutex_t locker;           //操作的原子性互斥性
pthread_cond_t notEmpty; //是否可读
    pthread_cond_t notFull;          //是否可写
    int posReadFrom;
int posWriteTo;
};int BufferIsFull（struct Products* products）
{
if （（products->posWriteTo + 1） % BUFFER_SIZE == products->posReadFrom）
{
return （1）;
}
return （0）;
}int BufferIsEmpty（struct Products* products）
{
if （products->posWriteTo == products->posReadFrom）
{
return （1）;
}return （0）;
} void Produce（struct Products* products, int item）
{
pthread_mutex_lock（&products->locker）; //原子操作while （BufferIsFull（products））
{
pthread_cond_wait（&products->notFull, &products->locker）;
} //写满了
    //写入
    products->buffer[products->posWriteTo] = item;
products->posWriteTo++;if （products->posWriteTo >= BUFFER_SIZE）
products->posWriteTo = 0;pthread_cond_signal（&products->notEmpty）;     //发送信号
    pthread_mutex_unlock（&products->locker）;    //解锁
}int Consume（struct Products* products）
{
int item;pthread_mutex_lock（&products->locker）;while （BufferIsEmpty（products））
{
pthread_cond_wait（&products->notEmpty, &products->locker）;
} //如果为空，等待
    item = products->buffer[products->posReadFrom];
products->posReadFrom++;if （products->posReadFrom >= BUFFER_SIZE）
        products->posReadFrom = 0;pthread_cond_signal（&products->notFull）;
pthread_mutex_unlock（&products->locker）;return item;
}
#define END_FLAG （-1）struct Products products;void* ProducerThread（void* data）
{
int i;
for （i = 0; i < 16; ++i）
{
printf（"producer: %d ", i）;
Produce（&products, i）;
}
Produce（&products, END_FLAG）;
return NULL;
}void* ConsumerThread（void* data）
{
int item;while （1）
{
item = Consume（&products）;
if （END_FLAG == item）
       break;
printf（"consumer: %d ", item）;
}
return （NULL）;
}int main（int argc, char* argv[]）
{
pthread_t producer;
pthread_t consumer;
int result;pthread_create（&producer, NULL, &ProducerThread, NULL）;
pthread_create（&consumer, NULL, &ConsumerThread, NULL）;pthread_join（producer, （void *）&result）;
pthread_join（consumer, （void *）&result）;
exit（EXIT_SUCCESS）;
}