84 lines
3.1 KiB
C
84 lines
3.1 KiB
C
/*
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* Copyright (c) 1988, 1989, 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Adam de Boor.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id$
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*/
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#ifndef lint
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static char sccsid[] = "@(#)lstOpen.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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/*-
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* LstOpen.c --
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* Open a list for sequential access. The sequential functions access the
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* list in a slightly different way. CurPtr points to their idea of the
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* current node in the list and they access the list based on it.
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* If the list is circular, Lst_Next and Lst_Prev will go around
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* the list forever. Lst_IsAtEnd must be used to determine when to stop.
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*/
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#include "lstInt.h"
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/*-
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*-----------------------------------------------------------------------
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* Lst_Open --
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* Open a list for sequential access. A list can still be searched,
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* etc., without confusing these functions.
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*
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* Results:
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* SUCCESS or FAILURE.
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*
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* Side Effects:
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* isOpen is set TRUE and curPtr is set to NilListNode so the
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* other sequential functions no it was just opened and can choose
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* the first element accessed based on this.
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*
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*-----------------------------------------------------------------------
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*/
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ReturnStatus
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Lst_Open (l)
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register Lst l;
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{
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if (LstValid (l) == FALSE) {
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return (FAILURE);
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}
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((List) l)->isOpen = TRUE;
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((List) l)->atEnd = LstIsEmpty (l) ? Head : Unknown;
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((List) l)->curPtr = NilListNode;
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return (SUCCESS);
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}
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