Linux下多线程producer/consumer模型

Linux下多线程producer/consumer模型

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

#define BUFFER_SIZE 8

struct 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\n", 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\n", 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);
}