/*
* Copyright (c) 2009 Dale DuRose
*
* 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.
*
*/
 
/*
*	This is an example queue written in c
*	this queue code is based on a linked list using pointers
* I'll be cleaning this code up in week
*/
 
#include <stdio.h>
#include <stdlib.h>
 
/* each node is a element of the queue */
typedef struct node
{
	struct node* next;
	void * data;
} Node;
 
/* basic queue structure */
typedef struct queue
{
	Node * end; /* end of the queue */
	Node * start; /* start of the queue */
	size_t length;
} Queue;
 
 
/* Node Operations */
Node * node_create(void* data, Node* next)
{
	Node * node = NULL;
	if((node = malloc(sizeof(Node))) != NULL)
	{
		node->data = data;
		node->next = next;
	}
	return node;
}
 
void node_delete(Node ** node)
{
	free(*node);
	*node = NULL;
}
 
/* queue operations */
Queue * queue_create()
{
	Queue * queue = NULL;
	if((queue = malloc(sizeof(Queue))) != NULL)
	{
		queue->end = NULL;
		queue->start = NULL;
		queue->length = 0;
	}
	return queue;
}
 
Node * queue_pop(Queue * queue)
{
	Node * node = NULL;
	if(queue->start != NULL)
	{
		node = queue->start;
		queue->start = queue->start->next;
		queue->length--;
	}
	return node;
}
 
void queue_delete(Queue ** queue)
{
	int i;
	size_t length = (*queue)->length;
	Node * node = NULL;
	for(i = 0; i < length; i++)
	{
		node = queue_pop(*queue);
		node_delete(&node);
	}
	free(*queue);
	*queue = NULL;
}
 
 
void queue_push(Queue * queue, Node * node)
{
 
	if(queue->start == NULL)
	{
		queue->start = node;
		queue->end = node;
		queue->length++;
	}
	else
	{
		queue->end->next = node;
		queue->end = queue->end->next;
		queue->length++;
	}
}
 
 
 
/* aux functions */
void print_queue(Queue * queue)
{
	Node * node = NULL;
	node = queue->start;
 
	while(node != NULL)
	{
		printf("%d \n",  *((int*) node->data));
		node = node->next;
	}
}
 
 
int main(int argc, char** argv)
{
	Queue * queue = NULL;
	Node * tempNode = NULL;
	int data[] = {90,30,40,27,1,39,28};
	const int length = 7;
	int i;
 
 
	printf("Loading Queue\n");
 
	queue = queue_create();
 
	for(i = 0; i < length; i++)
		queue_push(queue, node_create(data+i, NULL));
 
	printf("Queue Values\n------------------------------\n");
 
	print_queue(queue);
 
	printf("------------------------------\nEmptying Queue\n");
 
	queue_delete(&queue);
 
	return 0;
}