66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
/*-
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* listSetCirc.c --
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* Change the library's notion of the circularity of a list.
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*
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* Copyright (c) 1988 by the Regents of the University of California
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*
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* Copyright (c) 1988 by Adam de Boor
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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. 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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*
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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: lstSetCirc.c,v 1.3 88/11/17 20:54:04 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_SetCirc --
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* change the circularity of a list
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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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* The circularity of the list is set appropriately. The head and
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* tail of the list will be linked or unlinked as necessary
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*------------------------------------------------------------
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*/
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void
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Lst_SetCirc (l, circ)
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Lst l;
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Boolean circ;
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{
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register List list = (List) l;
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/*
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* if this isn't a change, do nothing.
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*/
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if ((list->isCirc && circ) || (!list->isCirc && !circ)) {
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return;
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}
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list->isCirc = circ;
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if (LstIsEmpty (l)) {
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return;
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}
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if (circ) {
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list->firstPtr->prevPtr = list->lastPtr;
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list->lastPtr->nextPtr = list->firstPtr;
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} else {
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list->firstPtr->prevPtr = NilListNode;
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list->lastPtr->nextPtr = NilListNode;
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}
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}
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