/*
 * Copyright (C) 2010-2012 Thomas Preud'homme <thomas.preud-homme@lip6.fr>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

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

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


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

	if (!posix_memalign((void *) &channel, CACHE_LINE_SIZE, sizeof(struct channel)))
	{
		int i;

		for (i = 0; i < SLOTS; i++)
			channel->queue[i].flag = 0;
		channel->head = 0;
		channel->tail = 0;
		return channel;
	}
	return NULL;
}

int end_producer(void *unused __attribute__ ((unused)))
{
	return 0;
}

int destroy_comm_channel(void *channel)
{
	free(channel);
	return 0;
}

void *recv_one_data(struct channel *channel)
{
	static __thread int i;
	void *result;

	if (__builtin_expect(!i, 0))
		while (!channel->queue[channel->head].flag);
	result = channel->queue[channel->head].chunk[i++];
	if (i % SUB_SLOTS)
	{
		i = 0;
		channel->queue[channel->head].flag = 0;
		channel->head = (channel->head + 1) % SLOTS;
	}
	return result;
}

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

	n = 0;
	// If all slots are empty, spin
	while (channel->queue[channel->head].flag)
	{
		unsigned int i;

		// Dequeue a chunk of data items
		for(i = 0; i < SUB_SLOTS; i++)
			*buf++ = channel->queue[channel->head].chunk[i];
		n += SUB_SLOTS;
		channel->queue[channel->head].flag = 0;
		channel->head = (channel->head + 1) % SLOTS;
		if (n == count)
			break;
	}
	return n;
}