/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * RemoteFX USB Redirection

 *

 * Copyright 2012 Atrust corp.

 * Copyright 2012 Alfred Liu <alfred.liu@atruscorp.com>

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *	 http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include "isoch_queue.h"

static void isoch_queue_rewind(ISOCH_CALLBACK_QUEUE* queue)

{

	queue->curr = queue->head;

}

static BOOL isoch_queue_has_next(ISOCH_CALLBACK_QUEUE* queue)

{

	return (queue->curr != NULL);

}

static ISOCH_CALLBACK_DATA* isoch_queue_get_next(ISOCH_CALLBACK_QUEUE* queue)

{

	ISOCH_CALLBACK_DATA* isoch;

	isoch = queue->curr;

	queue->curr = (ISOCH_CALLBACK_DATA*)queue->curr->next;

	return isoch;

}

static ISOCH_CALLBACK_DATA* isoch_queue_register_data(ISOCH_CALLBACK_QUEUE* queue, void* callback, void* dev)

{

	ISOCH_CALLBACK_DATA* isoch;

	isoch = (ISOCH_CALLBACK_DATA*) calloc(1, sizeof(ISOCH_CALLBACK_DATA));

	if (!isoch)

		return NULL;

	isoch->device = dev;

	isoch->callback = callback;

	pthread_mutex_lock(&queue->isoch_loading);

	if (queue->head == NULL)

	{

		/* linked queue is empty */

		queue->head = isoch;

		queue->tail = isoch;

	}

	else

	{

		/* append data to the end of the linked queue */

		queue->tail->next = (void*)isoch;

		isoch->prev = (void*)queue->tail;

		queue->tail = isoch;

	}

	queue->isoch_num += 1;

	pthread_mutex_unlock(&queue->isoch_loading);

	return isoch;

}

static int isoch_queue_unregister_data(ISOCH_CALLBACK_QUEUE* queue, ISOCH_CALLBACK_DATA* isoch)

{

	ISOCH_CALLBACK_DATA* p;

	queue->rewind(queue);

	while (queue->has_next(queue))

	{

		p = queue->get_next(queue);

		if (p != isoch)

			continue;

		/* data exists */

		/* set previous data to point to next data */

		if (isoch->prev != NULL)

		{

			/* unregistered data is not the head */

			p = (ISOCH_CALLBACK_DATA*)isoch->prev;

			p->next = isoch->next;

		}

		else

		{

			/* unregistered data is the head, update head */

			queue->head = (ISOCH_CALLBACK_DATA*)isoch->next;

		}

		/* set next data to point to previous data */

		if (isoch->next != NULL)

		{

			/* unregistered data is not the tail */

			p = (ISOCH_CALLBACK_DATA*)isoch->next;

			p->prev = isoch->prev;

		}

		else

		{

			/* unregistered data is the tail, update tail */

			queue->tail = (ISOCH_CALLBACK_DATA*)isoch->prev;

		}

		queue->isoch_num--;

		if (isoch)

		{

			/* free data info */

			isoch->out_data = NULL;

			zfree(isoch);

		}

		return 1; /* unregistration successful */

	}

	/* if we reach this point, the isoch wasn't found */

	return 0;

}

void isoch_queue_free(ISOCH_CALLBACK_QUEUE* queue)

{

	ISOCH_CALLBACK_DATA* isoch;

	pthread_mutex_lock(&queue->isoch_loading);

	/** unregister all isochronous data*/

	queue->rewind(queue);

	while (queue->has_next(queue))

	{

		isoch = queue->get_next(queue);

		if (isoch != NULL)

			queue->unregister_data(queue, isoch);

	}

	pthread_mutex_unlock(&queue->isoch_loading);

	pthread_mutex_destroy(&queue->isoch_loading);

	/* free queue */

	if (queue) 

		zfree(queue);

}

ISOCH_CALLBACK_QUEUE* isoch_queue_new()

{

	ISOCH_CALLBACK_QUEUE* queue;

	queue = (ISOCH_CALLBACK_QUEUE*) calloc(1, sizeof(ISOCH_CALLBACK_QUEUE));

	if (!queue)

		return NULL;

	pthread_mutex_init(&queue->isoch_loading, NULL);

	/* load service */

	queue->get_next = isoch_queue_get_next;

	queue->has_next = isoch_queue_has_next;

	queue->rewind = isoch_queue_rewind;

	queue->register_data = isoch_queue_register_data;

	queue->unregister_data = isoch_queue_unregister_data;

	queue->free = isoch_queue_free;

	return queue;

}