readers_and_writers

// Parallel.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

/*

pthread\include - здесь хедеры

pthread\lib\x86 - используем pthreadVSE2.lib

pthread\dll\x86 - используем pthreadVSE2.dll (нужно скопировать руками в
папку с приложением, либо добавить post build event, который, бы это делал)

*/

#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <vector>
#include <string>


std::vector<std::string> books;
pthread_mutex_t guardMutex;
pthread_cond_t cond_reader,cond_writer;
int numb_reader, numb_writer;


void *reader(void* prm)
{
    while(true)
    {
        pthread_mutex_lock(&guardMutex);
    bool is_full = books.size() > 50;
    if (books.empty())
    {
        pthread_cond_wait(&cond_reader, &guardMutex);
    }
    for (auto it = books.begin(); it != books.end(); ++it)
    {
        std::string rd = *it;
        std::cout << rd << std::endl;
        //std::cout << "OP - faggot " << std::endl;
    }
    if (is_full)
    {
        pthread_cond_signal(&cond_writer);
    }

    pthread_mutex_unlock(&guardMutex);
    }
    return 0;
}

void *writer(void *prm)
{
    while (true){
        pthread_mutex_lock(&guardMutex);
        bool is_empty = books.empty();
        if (books.size() > 5)
        {
            pthread_cond_wait(&cond_writer, &guardMutex);
        }
        for (int i = 0; i < 100; i++)
        {
            int numb = rand();
            char *string = new char[10];
            itoa(numb, string, 10);
            std::string str = string;
            books.push_back(str);
        }

        if (is_empty)
        {
            pthread_cond_signal(&cond_reader);
        }
        pthread_mutex_unlock(&guardMutex);
    }
    return 0;
}

int main()
{
    std::cout << "Write, how many reader and writer, next - push enter" << std::endl;
    std::cin >> numb_reader >> numb_writer;

    pthread_t thread_reader;
    pthread_t thread_writer;
    pthread_mutex_init(&guardMutex, 0);
    pthread_cond_init(&cond_reader, 0);
    pthread_cond_init(&cond_writer, 0);

    for (int i = 0; i < numb_reader; i++)
    {
        pthread_create(&thread_reader, 0, writer, 0);
    }

    for (int i = 0; i < numb_writer; i++)
    {
        pthread_create(&thread_writer, 0, reader, 0);
    }

    for (int i = 0; i < numb_reader; i++)
    {
        pthread_join(thread_reader, 0);
    }

    for (int i = 0; i < numb_writer; i++)
    {
        pthread_join(thread_writer, 0);
    }
    system("pause");


    return 0;
}