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

/* Non standard include */
#include <commtech.h>
#include <specific_comm.h>


__thread struct comm *comm;
const int batchSize = BUF_SIZE / sizeof(void *);

int init_library(void)
{
	return 0;
}

int finalize_library(void)
{
	return 0;
}

void *create_comm_channel(void)
{
	struct comm *comm;

	if (!posix_memalign((void *) &comm, CACHE_LINE_SIZE, sizeof(struct comm)))
	{
		if (!posix_memalign((void *) &comm->shared_space, CACHE_LINE_SIZE, SHARED_SPACE_SIZE))
		{
			comm->ctrl.read = 0;
			comm->ctrl.write = 0;
			comm->cons.localWrite = 0;
			comm->cons.nextRead = 0;
			comm->cons.rBatch = 0;
			comm->prod.localRead = 0;
			comm->prod.nextWrite = 0;
			comm->prod.wBatch = 0;
			return comm;
		}
		else
			free(comm);
	}
	return NULL;
}

int destroy_comm_channel(void *comm)
{
	free((void *) ((struct comm *) comm)->shared_space);
	free(comm);
	return 0;
}

int init_producer_thread(void *comm_param)
{
	comm = (struct comm *) comm_param;
	return 0;
}

int finalize_producer_thread(void *unused)
{
	comm = NULL;
	return 0;
}

int init_consumer_thread(void *comm_param)
{
	comm = (struct comm *) comm_param;
	return 0;
}

int finalize_consumer_thread(void *unused)
{
	comm = NULL;
	return 0;
}

void *recv_one_data(void)
{
	void *result;

	while (1)
	{
		if (comm->cons.nextRead == comm->cons.localWrite)
		{
			if (comm->cons.nextRead == comm->ctrl.write)
				continue;
			comm->cons.localWrite = comm->ctrl.write;
		}
		result = (void *) comm->shared_space[comm->cons.nextRead];
		comm->cons.nextRead = (comm->cons.nextRead + 1) % SHARED_SPACE_VOIDPTR;
		comm->cons.rBatch++;
		if (comm->cons.rBatch >= batchSize)
		{
			comm->ctrl.read = comm->cons.nextRead;
			comm->cons.rBatch = 0;
		}
		break;
	}
	return result;
}

ssize_t recv_some_data(void **buf, size_t count)
{
	int n;

	for(n = 0; n < count; n++)
	{
		if (comm->cons.nextRead == comm->cons.localWrite)
		{
			if (comm->cons.nextRead == comm->ctrl.write)
				break;
			comm->cons.localWrite = comm->ctrl.write;
		}

		/*
		 * The behaviour of this is not documented but we know
		 * the values inside buf won't change during this affectation
		 */
		*buf++ = (void *) comm->shared_space[comm->cons.nextRead];
		comm->cons.nextRead = (comm->cons.nextRead + 1) % SHARED_SPACE_VOIDPTR;
		comm->cons.rBatch++;
		if (comm->cons.rBatch >= batchSize)
		{
			comm->ctrl.read = comm->cons.nextRead;
			comm->cons.rBatch = 0;
		}
	}
	return n;
}