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

#define SIZE		16

int				jobs[SIZE];
int				in;
int				slots;
pthread_mutex_t	slots_mutex;
pthread_cond_t	slots_cond;
int				out;
int				items;
pthread_mutex_t	items_mutex;
pthread_cond_t	items_cond;

void put(int job);
void get(int* job);
void* prod(void* data);
void* cons(void* data);

int main(int argc,char** argv)
{
	pthread_t	prodid,consid;

	in = 0;
	slots = SIZE;
	pthread_mutex_init(&slots_mutex,0);
	pthread_cond_init(&slots_cond,0);
	out = 0;
	items = 0;
	pthread_mutex_init(&items_mutex,0);
	pthread_cond_init(&items_cond,0);

	pthread_setconcurrency(3);
	pthread_create(&prodid,0,prod,0);
	pthread_create(&consid,0,cons,0);

	pthread_join(prodid,0);
	pthread_join(consid,0);

	return 0;
}

void* prod(void* data)
{
	int	i;

	for (i=0; i<1000; i++)
	{
		if (!(i%100))
			printf("put %d\n",i);
		put(i);
	}
	put(-1);
	puts("prod done");

	return 0;
}

void* cons(void* data)
{
	int	i;
	do
	{
		get(&i);
		if (!(i%100))
			printf("got %d\n",i);
	}
	while (i>=0);
	puts("cons done");

	return 0;
}

void put(int job)
{
	pthread_mutex_lock(&slots_mutex);
		while (slots<=0)
			pthread_cond_wait(&slots_cond,&slots_mutex);
		jobs[in] = job;
		in++;
		in %= SIZE;
		slots--;
		items++;
	pthread_mutex_unlock(&slots_mutex);

	pthread_mutex_lock(&items_mutex);
		pthread_cond_signal(&items_cond);
	pthread_mutex_unlock(&items_mutex);
}

void get(int* job)
{
	pthread_mutex_lock(&items_mutex);
		while (items<=0)
			pthread_cond_wait(&items_cond,&items_mutex);
		*job = jobs[out];
		out++;
		out %= SIZE;
		items--;
		slots++;
	pthread_mutex_unlock(&items_mutex);

	pthread_mutex_lock(&slots_mutex);
		pthread_cond_signal(&slots_cond);
	pthread_mutex_unlock(&slots_mutex);
}