C语言实现PingPang Buffer：生产者-消费者模式

以下是一个使用C语言实现PingPang Buffer的简单示例：

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

#define BUFFER_SIZE 10

// PingPang Buffer 结构体
typedef struct {
    int buffer[BUFFER_SIZE];
    int read_index;
    int write_index;
    pthread_mutex_t mutex;
    pthread_cond_t read_cond;
    pthread_cond_t write_cond;
} PingPangBuffer;

// 初始化PingPang Buffer
void init_pingpang_buffer(PingPangBuffer* buffer) {
    buffer->read_index = 0;
    buffer->write_index = 0;
    pthread_mutex_init(&buffer->mutex, NULL);
    pthread_cond_init(&buffer->read_cond, NULL);
    pthread_cond_init(&buffer->write_cond, NULL);
}

// 写入数据到PingPang Buffer
void write_pingpang_buffer(PingPangBuffer* buffer, int data) {
    pthread_mutex_lock(&buffer->mutex);
    while ((buffer->write_index + 1) % BUFFER_SIZE == buffer->read_index) {
        pthread_cond_wait(&buffer->write_cond, &buffer->mutex);
    }
    buffer->buffer[buffer->write_index] = data;
    buffer->write_index = (buffer->write_index + 1) % BUFFER_SIZE;
    pthread_cond_signal(&buffer->read_cond);
    pthread_mutex_unlock(&buffer->mutex);
}

// 从PingPang Buffer读取数据
int read_pingpang_buffer(PingPangBuffer* buffer) {
    pthread_mutex_lock(&buffer->mutex);
    while (buffer->read_index == buffer->write_index) {
        pthread_cond_wait(&buffer->read_cond, &buffer->mutex);
    }
    int data = buffer->buffer[buffer->read_index];
    buffer->read_index = (buffer->read_index + 1) % BUFFER_SIZE;
    pthread_cond_signal(&buffer->write_cond);
    pthread_mutex_unlock(&buffer->mutex);
    return data;
}

// 测试程序
void* producer(void* arg) {
    PingPangBuffer* buffer = (PingPangBuffer*)arg;
    for (int i = 0; i < 20; i++) {
        write_pingpang_buffer(buffer, i);
        printf('producer write: %d\n', i);
    }
    return NULL;
}

void* consumer(void* arg) {
    PingPangBuffer* buffer = (PingPangBuffer*)arg;
    for (int i = 0; i < 20; i++) {
        int data = read_pingpang_buffer(buffer);
        printf('consumer read: %d\n', data);
    }
    return NULL;
}

int main() {
    PingPangBuffer buffer;
    init_pingpang_buffer(&buffer);

    pthread_t producer_thread, consumer_thread;
    pthread_create(&producer_thread, NULL, producer, &buffer);
    pthread_create(&consumer_thread, NULL, consumer, &buffer);

    pthread_join(producer_thread, NULL);
    pthread_join(consumer_thread, NULL);

    return 0;
}

该程序使用了一个PingPang Buffer结构体来实现数据的生产和消费。生产者线程通过调用write_pingpang_buffer函数向PingPang Buffer中写入数据，消费者线程通过调用read_pingpang_buffer函数从PingPang Buffer中读取数据。当PingPang Buffer已经满（即写指针和读指针相差1）时，生产者线程将被阻塞，直到有空间可用。当PingPang Buffer为空时，消费者线程将被阻塞，直到有数据可用。使用条件变量来实现线程的阻塞和唤醒。