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[unix-history] / usr / src / usr.bin / make / lst.lib / lstInt.h

/*
* Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Adam de Boor.
*
* %sccs.include.redist.c%
*
*      @(#)lstInt.h    5.3 (Berkeley) %G%
*/

/*-
* lstInt.h --
*      Internals for the list library
*/
#ifndef _LSTINT_H_
#define _LSTINT_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) Malloc (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_