生产者—消费者模式的两种同步实现

简要问题描述

一组生产者进程和一组消费者进程共享一个初始为空、大小为n的缓冲区，只有缓冲区没满时，生产者才能把消息放入到缓冲区，否则必须等待；只有缓冲区不空时，消费者才能从中取出消息，否则必须等待。由于缓冲区是临界资源，它只允许一个生产者放入消息，或者一个消费者从中取出消息。

生产者—消费者模式是非常经典的进程同步问题，我目前具体的两个简单实现为临界区（CriticalSection）同步和互斥（Mutex）同步，具体两者之间有何区别，可以参考负责任的链接，hhh~

Version1：

#include<windows.h>
#include<iostream>
#include<process.h>
#include<stdlib.h>
#include<time.h>
using namespace std;

const unsigned short Size = 10; // 缓冲区长度
unsigned short curValue = 0; // 当前产品数

bool g_continue = true;  // 控制程序结束 ：true（运行）；false（结束）

CRITICAL_SECTION g_cs; //临界区
HANDLE g_hFullSemaphore; //当缓冲区满时迫使生产者等待
HANDLE g_hEmptySemaphore; //当缓冲区空时迫使消费者等待
DWORD WINAPI Producer(LPVOID); //生产者线程
DWORD WINAPI Consumer(LPVOID); //消费者线程

int main() {

InitializeCriticalSection(&g_cs);  // 初始化临界区
g_hFullSemaphore = CreateSemaphore(NULL,Size-1,Size-1,NULL);
g_hEmptySemaphore = CreateSemaphore(NULL,0,Size-1,NULL);

//创建生产者线程
srand( (unsigned)time( NULL ) );
int t1 = rand()%(Size+1);
for (int i = 0; i < t1; i++) {
HANDLE producer = CreateThread(NULL,0,Producer,NULL,0,NULL);
}
//创建消费者线程
srand( (unsigned)time( NULL ) );
int t2 = rand()%(Size+1);
for (int i = 0; i < t2; i++) {
HANDLE consumer = CreateThread(NULL,0,Consumer,NULL,0,NULL);
}

while(g_continue){
if(getchar()) g_continue = false;   //按回车后终止程序运行
}
return 0;
}

void Produce() {
if (curValue == 10) return;
cout << "生产之前产品数为：" << curValue << endl;
curValue++;
cout << "Produce Succeed" << endl;
cout << "当前产品数为：" << curValue << endl;
cout << endl;
}

void Consume() {
if (curValue == 0) return;
cout << "消费之前产品数为：" << curValue << endl;
curValue--;
cout << "Consume Succeed" << endl;
cout << "当前产品数为：" << curValue << endl;
cout << endl;
}

//生产者
DWORD WINAPI Producer(LPVOID lpPara) {
while(g_continue){
WaitForSingleObject(g_hFullSemaphore,INFINITE);
EnterCriticalSection(&g_cs);
Produce();
Sleep(1000);
LeaveCriticalSection(&g_cs);
ReleaseSemaphore(g_hEmptySemaphore,1,NULL);
}
return 0;
}

//消费者
DWORD WINAPI Consumer(LPVOID lpPara) {
while(g_continue){
WaitForSingleObject(g_hEmptySemaphore,INFINITE);
EnterCriticalSection(&g_cs);
Consume();
Sleep(1000);
LeaveCriticalSection(&g_cs);
ReleaseSemaphore(g_hFullSemaphore,1,NULL);
}
return 0;
}

Version2：

#include<windows.h>
#include<iostream>
#include<stdlib.h>
#include<time.h>
using namespace std;

const unsigned short Size = 10; // 缓冲区长度
unsigned short curValue = 0; // 当前产品数

bool g_continue = true;  // 控制程序结束：true（运行）；false（结束）

HANDLE g_hMutex; //用于线程间的互斥
HANDLE g_hFullSemaphore; //当缓冲区满时迫使生产者等待
HANDLE g_hEmptySemaphore; //当缓冲区空时迫使消费者等待
DWORD WINAPI Producer(LPVOID); //生产者线程
DWORD WINAPI Consumer(LPVOID); //消费者线程

int main() {
//创建各个互斥信号
g_hMutex = CreateMutex(NULL,FALSE,NULL);
g_hFullSemaphore = CreateSemaphore(NULL,Size-1,Size-1,NULL);
g_hEmptySemaphore = CreateSemaphore(NULL,0,Size-1,NULL);

//创建生产者线程
srand( (unsigned)time( NULL ) );
int t1 = rand()%(Size+1);
for (int i = 0; i < t1; i++) {
HANDLE producer = CreateThread(NULL,0,Producer,NULL,0,NULL);
}
//创建消费者线程
srand( (unsigned)time( NULL ) );
int t2 = rand()%(Size+1);
for (int i = 0; i < t2; i++) {
HANDLE consumer = CreateThread(NULL,0,Consumer,NULL,0,NULL);
}

while(g_continue){
if(getchar()) g_continue = false;   //按回车后终止程序运行
}
return 0;
}

void Produce() {
if (curValue == 10) return;
cout << "生产之前产品数为：" << curValue << endl;
curValue++;
cout << "Produce Succeed" << endl;
cout << "当前产品数为：" << curValue << endl;
cout << endl;
}

void Consume() {
if (curValue == 0) return;
cout << "消费之前产品数为：" << curValue << endl;
curValue--;
cout << "Consume Succeed" << endl;
cout << "当前产品数为：" << curValue << endl;
cout << endl;
}

//生产者
DWORD WINAPI Producer(LPVOID lpPara) {
while(g_continue){
WaitForSingleObject(g_hFullSemaphore,INFINITE);
WaitForSingleObject(g_hMutex,INFINITE);
Produce();
Sleep(1000);
ReleaseMutex(g_hMutex);
ReleaseSemaphore(g_hEmptySemaphore,1,NULL);
}
return 0;
}

//消费者
DWORD WINAPI Consumer(LPVOID lpPara) {
while(g_continue){
WaitForSingleObject(g_hEmptySemaphore,INFINITE);
WaitForSingleObject(g_hMutex,INFINITE);
Consume();
Sleep(1000);
ReleaseMutex(g_hMutex);
ReleaseSemaphore(g_hFullSemaphore,1,NULL);
}
return 0;
}