56 lines
1.7 KiB
C
56 lines
1.7 KiB
C
/*-
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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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* 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: lstOpen.c,v 1.6 88/11/17 20:53:43 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_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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