87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/*-
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* lstForEachFrom.c --
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* Perform a given function on all elements of a list starting from
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* a given point.
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*
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* Copyright (c) 1988 by University of California Regents
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appears in all copies. Neither the University of California nor
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* Adam de Boor makes any representations about the suitability of this
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* software for any purpose. It is provided "as is" without
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* express or implied warranty.
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*/
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#if !defined(lint) && defined(keep_rcsid)
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static char *rcsid =
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"Id: lstForEachFrom.c,v 1.9 90/03/26 14:16:05 adam Exp $ SPRITE (Berkeley)";
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#endif lint
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#include "lstInt.h"
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/*-
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*-----------------------------------------------------------------------
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* Lst_ForEachFrom --
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* Apply the given function to each element of the given list. The
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* function should return 0 if traversal should continue and non-
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* zero if it should abort.
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*
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* Results:
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* None.
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*
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* Side Effects:
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* Only those created by the passed-in function.
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*
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*-----------------------------------------------------------------------
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*/
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/*VARARGS2*/
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void
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Lst_ForEachFrom (l, ln, proc, d)
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Lst l;
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LstNode ln;
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register int (*proc)();
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register ClientData d;
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{
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register ListNode tln = (ListNode)ln;
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register List list = (List)l;
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register ListNode next;
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Boolean done;
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int result;
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if (!LstValid (list) || LstIsEmpty (list)) {
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return;
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}
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do {
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/*
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* Take care of having the current element deleted out from under
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* us. Set "done" to indicate if we're currently on the last
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* element of the list.
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*/
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next = tln->nextPtr;
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done = ((next == list->firstPtr) || (next == NilListNode));
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tln->useCount++;
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result = (*proc) (tln->datum, d);
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tln->useCount--;
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/*
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* We're done with the traversal if
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* - nothing's been added after the current node and
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* - we were on the last node of the list before the callout.
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*/
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done = (next == tln->nextPtr && done);
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next = tln->nextPtr;
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if (tln->flags & LN_DELETED) {
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free((char *)tln);
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}
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tln = next;
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} while (!result && !LstIsEmpty(list) && !done);
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}
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