/*
 * 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 <pthread.h>
#include <unistd.h>

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


const unsigned int batchSize = 64; // Check with SHARED_SPACE_SIZE

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

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

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

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

void *recv_one_data(struct channel *channel)
{
	void *result;

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

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

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

		*buf++ = channel->shared_space[channel->cons.nextRead];
		channel->cons.nextRead = (channel->cons.nextRead + 1) % SHARED_SPACE_VOIDPTR;
		channel->cons.rBatch++;
		if (channel->cons.rBatch >= batchSize)
		{
			channel->ctrl.read = channel->cons.nextRead;
			channel->cons.rBatch = 0;
		}
	}
	return n;
}