/*
    This software may only be used by you under license from AT&T Corp.
    ("AT&T").  A copy of AT&T's Source Code Agreement is available at
    AT&T's Internet website having the URL:
    <http://www.research.att.com/sw/tools/graphviz/license/source.html>
    If you received this software without first entering into a license
    with AT&T, you have an infringing copy of this software and cannot use
    it without violating AT&T's intellectual property rights.
*/
#include	"dthdr.h"

#ifdef DMALLOC
#include "dmalloc.h"
#endif

/*	List, Stack, Queue.
**
**	Written by Kiem-Phong Vo (05/25/96)
*/

#if __STD_C
static Void_t* dtlist(reg Dt_t* dt, reg Void_t* obj, reg int type)
#else
static Void_t* dtlist(dt, obj, type)
reg Dt_t*	dt;
reg Void_t*	obj;
reg int		type;
#endif
{
	reg int		lk, sz, ky;
	reg Dtcompar_f	cmpf;
	reg Dtdisc_t*	disc;
	reg Dtlink_t	*r, *t;
	reg Void_t	*key, *k;

	INITDISC(dt,disc,ky,sz,lk,cmpf);

	if(!obj)
	{	if(type&(DT_LAST|DT_FIRST) )
		{	if((r = dt->data->head) )
			{	if(type&DT_LAST)
					r = r->left;
				dt->data->here = r;
			}
			return r ? OBJ(r,lk) : NIL(Void_t*);
		}
		else if(type&(DT_DELETE|DT_DETACH))
		{	if((dt->data->type&DT_LIST) || !(r = dt->data->head))
				return NIL(Void_t*);
			else	goto dt_delete;
		}
		else if(type&DT_CLEAR)
		{	if(disc->freef || disc->link < 0)
			{	for(r = dt->data->head; r; r = t)
				{	t = r->right;
					if(disc->freef)
						(*disc->freef)(dt,OBJ(r,lk),disc);
					if(disc->link < 0)
						(*dt->memoryf)(dt,(Void_t*)r,0,disc);
				}
			}
			dt->data->head = dt->data->here = NIL(Dtlink_t*);
			dt->data->size = 0;
			return NIL(Void_t*);
		}
		else	return NIL(Void_t*);
	}

	if(type&(DT_INSERT|DT_ATTACH))
	{	if(disc->makef && (type&DT_INSERT) &&
		   !(obj = (*disc->makef)(dt,obj,disc)) )
			return NIL(Void_t*);
		if(lk >= 0)
			r = ELT(obj,lk);
		else
		{	r = (Dtlink_t*)(*dt->memoryf)
				(dt,NIL(Void_t*),sizeof(Dthold_t),disc);
			if(r)
				((Dthold_t*)r)->obj = obj;
			else
			{	if(disc->makef && disc->freef && (type&DT_INSERT))
					(*disc->freef)(dt,obj,disc);
				return NIL(Void_t*);
			}
		}

		if(dt->data->type&DT_LIST)
		{	if((t = dt->data->here) && t != dt->data->head)
			{	r->left = t->left;
				t->left->right = r;
				r->right = t;
				t->left = r;
			}
			else	goto dt_stack;
		}
		else if(dt->data->type&DT_STACK)
		{ dt_stack:
			r->right = t = dt->data->head;
			if(t)
			{	r->left = t->left;
				t->left = r;
			}
			else	r->left = r;
			dt->data->head = r;
		}
		else /* if(dt->data->type&DT_QUEUE) */
		{	if((t = dt->data->head) )
			{	t->left->right = r;
				r->left = t->left;
				t->left = r;
			}
			else
			{	dt->data->head = r;
				r->left = r;
			}
			r->right = NIL(Dtlink_t*);
		}

		if(dt->data->size >= 0)
			dt->data->size += 1;

		dt->data->here = r;
		return OBJ(r,lk);
	}

	if((type&DT_MATCH) || !(r = dt->data->here) || OBJ(r,lk) != obj)
	{	key = (type&DT_MATCH) ? obj : KEY(obj,ky,sz);
		for(r = dt->data->head; r; r = r->right)
		{	k = OBJ(r,lk); k = KEY(k,ky,sz);
			if(CMP(dt,key,k,disc,cmpf,sz) == 0)
				break;
		}
	}

	if(!r)
		return NIL(Void_t*);

	if(type&(DT_DELETE|DT_DETACH))
	{ dt_delete:
		if(r->right)
			r->right->left = r->left;
		if(r == (t = dt->data->head) )
		{	dt->data->head = r->right;
			if(dt->data->head)
				dt->data->head->left = t->left;
		}
		else
		{	r->left->right = r->right;
			if(r == t->left)
				t->left = r->left;
		}

		dt->data->here = r == dt->data->here ? r->right : NIL(Dtlink_t*);
		dt->data->size -= 1;

		obj = OBJ(r,lk);
		if(disc->freef && (type&DT_DELETE))
			(*disc->freef)(dt,obj,disc);
		if(disc->link < 0)
			(*dt->memoryf)(dt,(Void_t*)r,0,disc);
		return obj;
	}
	else if(type&DT_NEXT)
		r = r->right;
	else if(type&DT_PREV)
		r = r == dt->data->head ? NIL(Dtlink_t*) : r->left;

	dt->data->here = r;
	return r ? OBJ(r,lk) : NIL(Void_t*);
}

#ifndef KPVDEL	/* to be remove next round */
#define static 
#endif
static Dtmethod_t _Dtlist  = { dtlist, DT_LIST  };
static Dtmethod_t _Dtstack = { dtlist, DT_STACK };
static Dtmethod_t _Dtqueue = { dtlist, DT_QUEUE };

__DEFINE__(Dtmethod_t*,Dtlist,&_Dtlist);
__DEFINE__(Dtmethod_t*,Dtstack,&_Dtstack);
__DEFINE__(Dtmethod_t*,Dtqueue,&_Dtqueue);