usr.bin/make/lst.lib/lstOpen.c

   1 /*      $NetBSD: lstOpen.c,v 1.12 2008/12/13 15:19:29 dsl Exp $ */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Adam de Boor.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef MAKE_NATIVE
  36 static char rcsid[] = "$NetBSD: lstOpen.c,v 1.12 2008/12/13 15:19:29 dsl Exp $";
  37 #else
  38 #include <sys/cdefs.h>
  39 #ifndef lint
  40 #if 0
  41 static char sccsid[] = "@(#)lstOpen.c   8.1 (Berkeley) 6/6/93";
  42 #else
  43 __RCSID("$NetBSD: lstOpen.c,v 1.12 2008/12/13 15:19:29 dsl Exp $");
  44 #endif
  45 #endif /* not lint */
  46 #endif
  47
  48 /*-
  49  * LstOpen.c --
  50  *      Open a list for sequential access. The sequential functions access the
  51  *      list in a slightly different way. CurPtr points to their idea of the
  52  *      current node in the list and they access the list based on it.
  53  *      If the list is circular, Lst_Next and Lst_Prev will go around
  54  *      the list forever. Lst_IsAtEnd must be used to determine when to stop.
  55  */
  56
  57 #include        "lstInt.h"
  58
  59 /*-
  60  *-----------------------------------------------------------------------
  61  * Lst_Open --
  62  *      Open a list for sequential access. A list can still be searched,
  63  *      etc., without confusing these functions.
  64  *
  65  * Results:
  66  *      SUCCESS or FAILURE.
  67  *
  68  * Side Effects:
  69  *      isOpen is set TRUE and curPtr is set to NULL so the
  70  *      other sequential functions no it was just opened and can choose
  71  *      the first element accessed based on this.
  72  *
  73  *-----------------------------------------------------------------------
  74  */
  75 ReturnStatus
  76 Lst_Open(Lst l)
  77 {
  78         if (LstValid (l) == FALSE) {
  79                 return (FAILURE);
  80         }
  81         (l)->isOpen = TRUE;
  82         (l)->atEnd = LstIsEmpty (l) ? Head : Unknown;
  83         (l)->curPtr = NULL;
  84
  85         return (SUCCESS);
  86 }
  87