contrib/bmake/lst.lib/lstForEachFrom.c

   1 /*      $NetBSD: lstForEachFrom.c,v 1.17 2009/01/23 21:26:30 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: lstForEachFrom.c,v 1.17 2009/01/23 21:26:30 dsl Exp $";
  37 #else
  38 #include <sys/cdefs.h>
  39 #ifndef lint
  40 #if 0
  41 static char sccsid[] = "@(#)lstForEachFrom.c    8.1 (Berkeley) 6/6/93";
  42 #else
  43 __RCSID("$NetBSD: lstForEachFrom.c,v 1.17 2009/01/23 21:26:30 dsl Exp $");
  44 #endif
  45 #endif /* not lint */
  46 #endif
  47
  48 /*-
  49  * lstForEachFrom.c --
  50  *      Perform a given function on all elements of a list starting from
  51  *      a given point.
  52  */
  53
  54 #include        "lstInt.h"
  55
  56 /*-
  57  *-----------------------------------------------------------------------
  58  * Lst_ForEachFrom --
  59  *      Apply the given function to each element of the given list. The
  60  *      function should return 0 if traversal should continue and non-
  61  *      zero if it should abort.
  62  *
  63  * Results:
  64  *      None.
  65  *
  66  * Side Effects:
  67  *      Only those created by the passed-in function.
  68  *
  69  *-----------------------------------------------------------------------
  70  */
  71 /*VARARGS2*/
  72 int
  73 Lst_ForEachFrom(Lst l, LstNode ln, int (*proc)(void *, void *),
  74                 void *d)
  75 {
  76     ListNode    tln = ln;
  77     List        list = l;
  78     ListNode    next;
  79     Boolean             done;
  80     int                 result;
  81
  82     if (!LstValid (list) || LstIsEmpty (list)) {
  83         return 0;
  84     }
  85
  86     do {
  87         /*
  88          * Take care of having the current element deleted out from under
  89          * us.
  90          */
  91
  92         next = tln->nextPtr;
  93
  94         /*
  95          * We're done with the traversal if
  96          *  - the next node to examine is the first in the queue or
  97          *    doesn't exist and
  98          *  - nothing's been added after the current node (check this
  99          *    after proc() has been called).
 100          */
 101         done = (next == NULL || next == list->firstPtr);
 102
 103         (void) tln->useCount++;
 104         result = (*proc) (tln->datum, d);
 105         (void) tln->useCount--;
 106
 107         /*
 108          * Now check whether a node has been added.
 109          * Note: this doesn't work if this node was deleted before
 110          *       the new node was added.
 111          */
 112         if (next != tln->nextPtr) {
 113                 next = tln->nextPtr;
 114                 done = 0;
 115         }
 116
 117         if (tln->flags & LN_DELETED) {
 118             free((char *)tln);
 119         }
 120         tln = next;
 121     } while (!result && !LstIsEmpty(list) && !done);
 122
 123     return result;
 124 }
 125