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1.1 ! root 1: /* ! 2: * Copyright (c) 1988, 1989, 1990 The Regents of the University of California. ! 3: * All rights reserved. ! 4: * ! 5: * This code is derived from software contributed to Berkeley by ! 6: * Adam de Boor. ! 7: * ! 8: * Redistribution and use in source and binary forms are permitted ! 9: * provided that: (1) source distributions retain this entire copyright ! 10: * notice and comment, and (2) distributions including binaries display ! 11: * the following acknowledgement: ``This product includes software ! 12: * developed by the University of California, Berkeley and its contributors'' ! 13: * in the documentation or other materials provided with the distribution ! 14: * and in all advertising materials mentioning features or use of this ! 15: * software. Neither the name of the University nor the names of its ! 16: * contributors may be used to endorse or promote products derived ! 17: * from this software without specific prior written permission. ! 18: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR ! 19: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED ! 20: * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. ! 21: */ ! 22: ! 23: #ifndef lint ! 24: static char sccsid[] = "@(#)lstOpen.c 5.3 (Berkeley) 6/1/90"; ! 25: #endif /* not lint */ ! 26: ! 27: /*- ! 28: * LstOpen.c -- ! 29: * Open a list for sequential access. The sequential functions access the ! 30: * list in a slightly different way. CurPtr points to their idea of the ! 31: * current node in the list and they access the list based on it. ! 32: * If the list is circular, Lst_Next and Lst_Prev will go around ! 33: * the list forever. Lst_IsAtEnd must be used to determine when to stop. ! 34: */ ! 35: ! 36: #include "lstInt.h" ! 37: ! 38: /*- ! 39: *----------------------------------------------------------------------- ! 40: * Lst_Open -- ! 41: * Open a list for sequential access. A list can still be searched, ! 42: * etc., without confusing these functions. ! 43: * ! 44: * Results: ! 45: * SUCCESS or FAILURE. ! 46: * ! 47: * Side Effects: ! 48: * isOpen is set TRUE and curPtr is set to NilListNode so the ! 49: * other sequential functions no it was just opened and can choose ! 50: * the first element accessed based on this. ! 51: * ! 52: *----------------------------------------------------------------------- ! 53: */ ! 54: ReturnStatus ! 55: Lst_Open (l) ! 56: register Lst l; ! 57: { ! 58: if (LstValid (l) == FALSE) { ! 59: return (FAILURE); ! 60: } ! 61: ((List) l)->isOpen = TRUE; ! 62: ((List) l)->atEnd = LstIsEmpty (l) ? Head : Unknown; ! 63: ((List) l)->curPtr = NilListNode; ! 64: ! 65: return (SUCCESS); ! 66: } ! 67:
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