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//typical sample of multithread
//VS2005
#include <windows.h>
#include <process.h>
#include <stdio.h>

enum { BUFFERSIZE = 3 };

int g_buffer[BUFFERSIZE];       //global buffer to simulate a queue

HANDLE g_hMutex;
HANDLE g_hNotFullSemaphore,g_hNotEmptySemaphore;

DWORD WINAPI producer(LPVOID lpParam);
DWORD WINAPI consumer(LPVOID lpParam);

int main()
{
    g_hMutex = CreateMutex(NULL,FALSE,NULL);
    if(g_hMutex==NULL)
    {
        printf("failed to create handle mutex\n");
        return EXIT_FAILURE;
    }
    //initial value BUFFERSIZE-1
    g_hNotFullSemaphore = CreateSemaphore(NULL,BUFFERSIZE-1,BUFFERSIZE-1,NULL);//signalled
    if(g_hNotFullSemaphore==NULL)
    {
        printf("failed to create full semaphore\n");
        return EXIT_FAILURE;
    }
    //initial value 0
    g_hNotEmptySemaphore = CreateSemaphore(NULL,0,BUFFERSIZE-1,NULL);//not signalled
    if(g_hNotEmptySemaphore==NULL)
    {
        printf("failed to create empty semaphore\n");
        return EXIT_FAILURE;
    }
    HANDLE hThread[2];
    DWORD dwThreadID;
    LPTSTR lpProducerParam("producing product ");
    LPTSTR lpConsumerParam("consuming product ");

    hThread[0] = CreateThread(
        NULL,
        0,
        producer,
        lpProducerParam,
        0,
        &dwThreadID );
    if(hThread[0] == NULL)
    {
        printf("failed to create producer thread\n");
        return EXIT_FAILURE;
    }

    hThread[1] = CreateThread(
        NULL,
        0,
        consumer,
        lpConsumerParam,
        0,
        &dwThreadID );
    if(hThread[1] == NULL)
    {
        printf("failed to create consumer thread\n");
        return EXIT_FAILURE;
    }

    WaitForMultipleObjects(2,hThread,TRUE,INFINITE);
    CloseHandle(hThread[0]);
    CloseHandle(hThread[1]);

    ReleaseMutex(g_hMutex);
    CloseHandle(g_hMutex);

    return EXIT_SUCCESS;

}

DWORD WINAPI producer(LPVOID lpParam)
{
    int count = 0;
    for(int i=10;i>=0;i--)
    {
        WaitForSingleObject(g_hNotFullSemaphore,INFINITE); // if get ownership of shared source,NotFullsemaphore decreased by 1
        WaitForSingleObject(g_hMutex,INFINITE);
        g_buffer[count] = i;
        count = (count+1)%BUFFERSIZE;

        printf("%s:%d\n",(LPTSTR)lpParam,i);
        Sleep(100);
        ReleaseMutex(g_hMutex);
        ReleaseSemaphore(g_hNotEmptySemaphore,1,NULL);//NotEmptySemaphore increased by 1
    }

    return EXIT_SUCCESS;

}

DWORD WINAPI consumer(LPVOID lpParam)
{
    int count = 0;
    int result;
    while(1)
    {
        WaitForSingleObject(g_hNotEmptySemaphore,INFINITE);
        WaitForSingleObject(g_hMutex,INFINITE);
        result = g_buffer[count];
       
        Sleep(80);
        printf("%s:%d\n",(LPTSTR)lpParam,result);
        if(result ==0)
        {
            printf("exiting thread...\n");
            ExitThread(EXIT_SUCCESS);
        }

        count =(count+1)%BUFFERSIZE;
        ReleaseMutex(g_hMutex);
        ReleaseSemaphore(g_hNotFullSemaphore,1,NULL);
    }
   
    return EXIT_SUCCESS;
}