/*	$OpenBSD: lstInt.h,v 1.6 1998/12/05 00:06:32 espie Exp $	*/
/*	$NetBSD: lstInt.h,v 1.7 1996/11/06 17:59:44 christos Exp $	*/

/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	from: @(#)lstInt.h	8.1 (Berkeley) 6/6/93
 */

/*-
 * lstInt.h --
 *	Internals for the list library
 */
#ifndef _LSTINT_H_
#define _LSTINT_H_

#include	  "make.h"
#include	  "lst.h"

typedef struct ListNode {
	struct ListNode	*prevPtr;   /* previous element in list */
	struct ListNode	*nextPtr;   /* next in list */
	short	    	useCount:8, /* Count of functions using the node.
				     * node may not be deleted until count
				     * goes to 0 */
 	    	    	flags:8;    /* Node status flags */
	ClientData	datum;	    /* datum associated with this element */
} *ListNode;
/*
 * Flags required for synchronization
 */
#define LN_DELETED  	0x0001      /* List node should be removed when done */

#define NilListNode	((ListNode)-1)

typedef enum {
    Head, Middle, Tail, Unknown
} Where;

typedef struct	{
	ListNode  	firstPtr; /* first node in list */
	ListNode  	lastPtr;  /* last node in list */
	Boolean	  	isCirc;	  /* true if the list should be considered
				   * circular */
/*
 * fields for sequential access
 */
	Where	  	atEnd;	  /* Where in the list the last access was */
	Boolean	  	isOpen;	  /* true if list has been Lst_Open'ed */
	ListNode  	curPtr;	  /* current node, if open. NilListNode if
				   * *just* opened */
	ListNode  	prevPtr;  /* Previous node, if open. Used by
				   * Lst_Remove */
} *List;

#define NilList	  	((List)-1)

/*
 * PAlloc (var, ptype) --
 *	Allocate a pointer-typedef structure 'ptype' into the variable 'var'
 */
#define	PAlloc(var,ptype)	var = (ptype) emalloc (sizeof (*var))

/*
 * LstValid (l) --
 *	Return TRUE if the list l is valid
 */
#define LstValid(l)	(((Lst)l == NILLST) ? FALSE : TRUE)

/*
 * LstNodeValid (ln, l) --
 *	Return TRUE if the LstNode ln is valid with respect to l
 */
#define LstNodeValid(ln, l)	((((LstNode)ln) == NILLNODE) ? FALSE : TRUE)

/*
 * LstIsEmpty (l) --
 *	TRUE if the list l is empty.
 */
#define LstIsEmpty(l)	(((List)l)->firstPtr == NilListNode)

#endif /* _LSTINT_H_ */
