20-producer-consumer-multiplication-condition-variables.c

// Run Using "gcc -pthread 20_producer_consumer_multi_condition_variables.c && ./a.out"

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

#define MAX 10
#define OPR 25
#define PRO 3
#define CON 3

pthread_mutex_t buf_lock;
pthread_cond_t less, more;
pthread_mutex_t num_lock;

typedef struct str {
    pthread_mutex_t* buf_lock;
    pthread_cond_t* less;
    pthread_cond_t* more;
    pthread_mutex_t* num_lock;
    int* buffer;
    int* head;
    int* tail;
    int* num;
} str;

void* producer(pthread_mutex_t* buf_lock, pthread_cond_t* less, pthread_cond_t* more, int* buffer, int* head, int* tail, int data) {
    pthread_mutex_lock(buf_lock);
    while ((*tail + 1) % MAX == *head) {
        printf("Buffer is full. Producer is waiting.\n");
        pthread_cond_wait(less, buf_lock);
    }
    buffer[*tail] = data;
    *tail = (*tail + 1) % MAX;
    pthread_cond_signal(more);
    pthread_mutex_unlock(buf_lock);

    return NULL;
}

int consume(pthread_mutex_t* buf_lock, pthread_cond_t* less, pthread_cond_t* more, int* buffer, int* head, int* tail) {
    pthread_mutex_lock(buf_lock);
    while (*head == *tail) {
        printf("Buffer is empty. Consumer is waiting.\n");
        pthread_cond_wait(more, buf_lock);
    }
    int data = buffer[*head];
    *head = (*head + 1) % MAX;
    pthread_cond_signal(less);
    pthread_mutex_unlock(buf_lock);

    return data;
}

void* producer_thread(void* vargp) {
    str* s = (str*)vargp;
    pthread_mutex_t* buf_lock = s->buf_lock;
    pthread_cond_t* less = s->less;
    pthread_cond_t* more = s->more;
    pthread_mutex_t* num_lock = s->num_lock;
    int* buffer = s->buffer;
    int* head = s->head;
    int* tail = s->tail;
    int* num = s->num;
    free(s);
    srand(time(NULL));

    for (int i = 0; i < OPR; i++) {
        int data = rand() % 100 + 1;
        pthread_mutex_lock(num_lock);
        printf("num = %d + %d = %d\n", *num, data, *num + data);
        *num = *num + data;
        pthread_mutex_unlock(num_lock);
        producer(buf_lock, less, more, buffer, head, tail, data);
        // usleep(100);
    }

    return NULL;
}

void* consumer_thread(void* vargp) {
    str* s = (str*)vargp;
    pthread_mutex_t* buf_lock = s->buf_lock;
    pthread_cond_t* less = s->less;
    pthread_cond_t* more = s->more;
    pthread_mutex_t* num_lock = s->num_lock;
    int* buffer = s->buffer;
    int* head = s->head;
    int* tail = s->tail;
    int* num = s->num;
    free(s);
    srand(time(NULL));

    for (int i = 0; i < OPR; i++) {
        int data = consume(buf_lock, less, more, buffer, head, tail);
        pthread_mutex_lock(num_lock);
        printf("num = %d - %d = %d\n", *num, data, *num - data);
        *num = *num - data;
        pthread_mutex_unlock(num_lock);
        // usleep(100);
    }

    return NULL;
}

int main() {
    int buffer[MAX];
    int head = 0, tail = 0;
    int num = 0;

    pthread_t p[PRO];
    pthread_t c[CON];

    // Mutex Lock Implementation
    printf("Mutex Lock + Condition Variables Implementation (Multiple Producer-Consumer):\n");

    str* s1;

    for (int i = 0; i < PRO; i++) {
        s1 = (str*)malloc(sizeof(str));
        s1->buf_lock = &buf_lock;
        s1->less = &less;
        s1->more = &more;
        s1->num_lock = &num_lock;
        s1->buffer = buffer;
        s1->head = &head;
        s1->tail = &tail;
        s1->num = &num;
        pthread_create(&p[i], NULL, producer_thread, s1);
    }

    str* s2;

    for (int i = 0; i < CON; i++) {
        s2 = (str*)malloc(sizeof(str));
        s2->buf_lock = &buf_lock;
        s2->less = &less;
        s2->more = &more;
        s2->num_lock = &num_lock;
        s2->buffer = buffer;
        s2->head = &head;
        s2->tail = &tail;
        s2->num = &num;
        pthread_create(&c[i], NULL, consumer_thread, s2);
    }

    for (int i = 0; i < PRO; i++)
        pthread_join(p[i], NULL);

    for (int i = 0; i < CON; i++)
        pthread_join(c[i], NULL);

    printf("Result: %s\n", num == 0 ? "Success" : "Fail");

    return 0;
}