/*
dlist.c
Pedro Flynn - pflynn@microsoftsucks.org
*/

#include "dlist.h"

#ifdef __cplusplus
extern "C" {
#endif
	
DList* dlist_create(int (*match)(const void*,const void*),void (*destroy)(void*))
{
DList* dlist;
	if(!(dlist = (DList*) malloc(sizeof(DList))))
		return NULL;
  
	dlist->match = match;
	dlist->destroy = destroy;
	dlist->size = 0;
	dlist->head = dlist->tail = NULL;
	
	return dlist;
}


DListElement* dlist_insert_next(DList* dlist,DListElement* element,void* data)
{
	DListElement* newelement;
	
	if(!element && dlist->size)
		return NULL;
	
	if(!(newelement = (DListElement*) malloc(sizeof(DListElement))))
		return NULL;
	
	newelement->data = data;
	
	
	if(!element){
		dlist->head = dlist->tail = newelement;
		newelement->next = newelement->prev = NULL;
		}else{
			if(!(newelement->next = element->next))
				dlist->tail = newelement;
			else
				element->next->prev = newelement;
			
			newelement->prev = element;
			element->next = newelement;
			
			
			}
			
			dlist->size++;
      return newelement;		
		}

DListElement* dlist_insert_prev(DList* dlist,DListElement* element,void* data)
{
DListElement* newelement;
	
if(!element && dlist->size)
	return NULL;

if(!(newelement = (DListElement*) malloc(sizeof(DListElement))))
	return NULL;

newelement->data = data;

if(!element){
	dlist->head = dlist->tail = newelement;
		newelement->next = newelement->prev = NULL;
		}else{
			newelement->next = element;
			if(!(newelement->prev = element->prev))
				dlist->head = newelement;
			else
				element->prev->next = newelement;
			  
			element->prev = newelement;
				
			}
dlist->size++;
return newelement;
}


int dlist_remove_element(DList* dlist,DListElement* element,void** data)
{

	if(!dlist->size || !element)
		return -1;
	
	if(element->prev)
		element->prev->next = element->next;
	else
		dlist->head = element->next;
	
	if(element->next)
		element->next->prev = element->prev;
	else
		dlist->tail = element->prev;
		
	*data = element->data;
	
	free(element);
	dlist->size--;
	return 0;
}

DListElement* dlist_get_element(DList* dlist,const void* data)
{
DListElement* element;
	
	if(!dlist->match || !dlist->size)
		return NULL;


element = dlist->head;
	
do
	if(dlist->match(element->data,data))
		return element;
	while(element = element->next);
		
	return NULL;
}

void dlist_destroy(DList* dlist)
{
void* data;
	
	while(dlist->size)
		if(!dlist_remove_element(dlist,dlist->head,(void**) &data) && dlist->destroy)
			dlist->destroy(data);
		
	free(dlist);
}


DListElement* dlist_enqueue_element(DList* dlist,void* data)
{
	return dlist_insert_next(dlist,dlist->tail,data);	
}

int dlist_dequeue_element(DList *dlist,void** data)
{
	return dlist_remove_element(dlist,dlist->head,data);	
}

DListElement* dlist_push_element(DList *dlist,void* data)
{
	return dlist_insert_prev(dlist,dlist->head,data);
}

int dlist_pop_element(DList *dlist,void** data)
{
	return dlist_remove_element(dlist,dlist->head,data);	
}

#ifdef __cplusplus
}
#endif