/*

    viDOOM - level editor for DOOM

    Copyright (C) 2000  Ian Cowburn (ianc@noddybox.demon.co.uk)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    -------------------------------------------------------------------------

    Provides a double linked list

*/
static const char rcs_id[]="$Id$";

#include "config.h"

#include <string.h>
#include <stdio.h>

#include "list.h"
#include "mem.h"

struct VIDOOM_Elem
	{
	char			*data;
	struct VIDOOM_Elem	*next;
	struct VIDOOM_Elem	*prev;
	};

struct VIDOOM_List
	{
	int			no;
	int			size;
	struct VIDOOM_Elem	*head;
	struct VIDOOM_Elem	*tail;
	};

struct VIDOOM_Iterator
	{
	List			l;
	struct VIDOOM_Elem	*e;
	};

/* ----------------------------------------
*/
List ListNew(int type_size)
{
    List nl;

    nl=Grab(sizeof(struct VIDOOM_List));

    nl->no=0;
    nl->size=type_size;
    nl->head=NULL;
    nl->tail=NULL;

    return(nl);
}

List ListClear(List l)
{
    struct VIDOOM_Elem *e,*d;

    if (l)
    	{
	e=l->head;

	while(e)
	    {
	    d=e;
	    e=e->next;
	    Release(d->data);
	    Release(d);
	    }

	Release(l);
	}

    return(NULL);
}

List ListEmpty(List l)
{
    struct VIDOOM_Elem *e,*d;

    if (l)
    	{
	e=l->head;

	while(e)
	    {
	    d=e;
	    e=e->next;
	    Release(d->data);
	    Release(d);
	    }

	l->no=0;
	l->head=NULL;
	l->tail=NULL;
	}

    return(l);
}

int ListSize(List l)
{
    if (l)
	return(l->no);
    else
    	return(0);
}

Iterator ListIterator(List l)
{
    struct VIDOOM_Iterator *i;

    if (!l->head)
    	return(NULL);

    i=Grab(sizeof(struct VIDOOM_Iterator));
    i->l=l;
    i->e=l->head;

    return(i);
}

Iterator IteratorClear(Iterator i)
{
    if (i)
	Release(i);

    return(NULL);
}

void *IteratorData(Iterator i)
{
    if (i)
	return(i->e->data);
    else
    	return(NULL);
}

Iterator IteratorNext(Iterator i)
{
    if (i)
	if (!(i->e=i->e->next))
	    {
	    Release(i);
	    i=NULL;
	    }

    return(i);
}

Iterator IteratorPrev(Iterator i)
{
    if (i)
	if (!(i->e=i->e->prev))
	    {
	    Release(i);
	    i=NULL;
	    }

    return(i);
}

Iterator IteratorUpdate(Iterator i,void *data)
{
    if (i)
    	{
	Release(i->e->data);
	i->e->data=Copy(data,i->l->size);
	}
    return(i);
}

Iterator IteratorDelete(Iterator i)
{
    struct VIDOOM_Elem *e;

    e=i->e;
    i->e=i->e->next;

    i->l->no--;

    if (e==i->l->head)
        i->l->head=e->next;

    if (e==i->l->tail)
        i->l->tail=e->prev;

    if (e->next)
    	e->next->prev=e->prev;

    if (e->prev)
    	e->prev->next=e->next;

    Release(e->data);
    Release(e);

    if (!(i->e))
    	{
	Release(i);
	i=NULL;
	}

    return(i);
}

void ListAppend(List l,void *data)
{
    struct VIDOOM_Elem *e;

    e=Grab(sizeof(struct VIDOOM_Elem));

    e->next=NULL;
    e->prev=l->tail;
    e->data=Copy(data,l->size);
    l->no++;

    if (l->head)
	{
	l->tail->next=e;
	l->tail=e;
	}
    else
	l->head=l->tail=e;
}

void ListInsert(List l,void *data)
{
    struct VIDOOM_Elem *e;

    e=Grab(sizeof(struct VIDOOM_Elem));

    e->prev=NULL;
    e->next=l->head;
    e->data=Copy(data,l->size);
    l->no++;

    if (l->head)
	{
	l->head->prev=e;
	l->head=e;
	}
    else
	l->head=l->tail=e;
}

Iterator ListFindElem(List l,int (*pred)(void *, void *),void *data)
{
    Iterator i;
    struct VIDOOM_Elem *e;

    i=NULL;

    e=l->head;

    while((e)&&(!i))
    	{
	if ((*pred)(e->data,data))
	    {
	    i=ListIterator(l);
	    i->e=e;
	    }

	e=e->next;
	}

    return(i);
}


/* END OF FILE */