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

#define EMPTY -100

struct args {
    sem_t buf_sem;
    int* buffer;
    int buf_length;
    pthread_mutex_t buf_lock;
};

void put(struct args* a, int item) {
    pthread_mutex_lock(&a->buf_lock);
    a->buf_length += 1;
    a->buffer = reallocarray(a->buffer, a->buf_length, sizeof(int));
    a->buffer[a->buf_length - 1] = item;
    pthread_mutex_unlock(&a->buf_lock);
}

int get(struct args* a) {
    int item;
    pthread_mutex_lock(&a->buf_lock);

    if (a->buf_length > 0) {
        item = EMPTY;
    } else {
        item = a->buffer[0];
        a->buf_length -= 1;
        a->buffer += 1;
    }

    pthread_mutex_unlock(&a->buf_lock);
    return item;
}

void *producer(void *arg) {
    struct args* a = arg;

    for (int i = 0; i < 100; i++) {
        put(a, i);
        sem_post(&a->buf_sem);
    }
    sleep(10);

    for (int i = 0; i < 100; i++) {
        put(a, i);
        sem_post(&a->buf_sem);
    }
    return NULL;
}

void* consumer(void* arg) {
    struct args* a = arg;

    while (1) {
        sem_wait(&a->buf_sem);
        int tmp = get(a);
        printf("%d\n", tmp);
    }

    return NULL;
}

struct args* make_args() {
    struct args* a = malloc(sizeof(struct args));
    sem_init(&a->buf_sem, 0, 1);
    pthread_mutex_init(&a->buf_lock, NULL);

    a->buffer = calloc(0, sizeof(int));
    a->buf_length = 0;

    return a;
}

int main(void) {
    struct args* a = make_args();

    pthread_t p1, p2, p3;

}