usr/src/usr.bin/make/lst.lib/lstForEachFrom.c

/*
 * 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.
 */

#ifndef lint
static char sccsid[] = "@(#)lstForEachFrom.c    8.1 (Berkeley) 6/6/93";
#endif /* not lint */

/*-
 * lstForEachFrom.c --
 *      Perform a given function on all elements of a list starting from
 *      a given point.
 */

#include        "lstInt.h"

/*-
 *-----------------------------------------------------------------------
 * Lst_ForEachFrom --
 *      Apply the given function to each element of the given list. The
 *      function should return 0 if traversal should continue and non-
 *      zero if it should abort.
 *
 * Results:
 *      None.
 *
 * Side Effects:
 *      Only those created by the passed-in function.
 *
 *-----------------------------------------------------------------------
 */
/*VARARGS2*/
void
Lst_ForEachFrom (l, ln, proc, d)
    Lst                 l;
    LstNode             ln;
    register int        (*proc)();
    register ClientData d;
{
    register ListNode   tln = (ListNode)ln;
    register List       list = (List)l;
    register ListNode   next;
    Boolean             done;
    int                 result;

    if (!LstValid (list) || LstIsEmpty (list)) {
        return;
    }

    do {
        /*
         * Take care of having the current element deleted out from under
         * us.
         */

        next = tln->nextPtr;

        (void) tln->useCount++;
        result = (*proc) (tln->datum, d);
        (void) tln->useCount--;

        /*
         * We're done with the traversal if
         *  - nothing's been added after the current node and
         *  - the next node to examine is the first in the queue or
         *    doesn't exist.
         */
        done = (next == tln->nextPtr &&
                (next == NilListNode || next == list->firstPtr));

        next = tln->nextPtr;

        if (tln->flags & LN_DELETED) {
            free((char *)tln);
        }
        tln = next;
    } while (!result && !LstIsEmpty(list) && !done);

}