projects / unix-history / blame
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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 | * | |
| 1c15e888 C |
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. | |
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21 | */ |
| 22 | ||
| 23 | #ifndef lint | |
| 1c15e888 | 24 | static char sccsid[] = "@(#)lstIsAtEnd.c 5.3 (Berkeley) 6/1/90"; |
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25 | #endif /* not lint */ |
| 26 | ||
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27 | /*- |
| 28 | * LstIsAtEnd.c -- | |
| 29 | * Tell if the current node is at the end of the list. | |
| 30 | * The sequential functions access the list in a slightly different way. | |
| 31 | * CurPtr points to their idea of the current node in the list and they | |
| 32 | * access the list based on it. Because the list is circular, Lst_Next | |
| 33 | * and Lst_Prev will go around the list forever. Lst_IsAtEnd must be | |
| 34 | * used to determine when to stop. | |
| c65fedcf | 35 | */ |
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36 | |
| 37 | #include "lstInt.h" | |
| 38 | ||
| 39 | /*- | |
| 40 | *----------------------------------------------------------------------- | |
| 41 | * Lst_IsAtEnd -- | |
| 42 | * Return true if have reached the end of the given list. | |
| 43 | * | |
| 44 | * Results: | |
| 45 | * TRUE if at the end of the list (this includes the list not being | |
| 46 | * open or being invalid) or FALSE if not. We return TRUE if the list | |
| 47 | * is invalid or unopend so as to cause the caller to exit its loop | |
| 48 | * asap, the assumption being that the loop is of the form | |
| 49 | * while (!Lst_IsAtEnd (l)) { | |
| 50 | * ... | |
| 51 | * } | |
| 52 | * | |
| 53 | * Side Effects: | |
| 54 | * None. | |
| 55 | * | |
| 56 | *----------------------------------------------------------------------- | |
| 57 | */ | |
| 58 | Boolean | |
| 59 | Lst_IsAtEnd (l) | |
| 60 | Lst l; | |
| 61 | { | |
| 62 | register List list = (List) l; | |
| 63 | ||
| 64 | return (!LstValid (l) || !list->isOpen || | |
| 65 | (list->atEnd == Head) || (list->atEnd == Tail)); | |
| 66 | } | |
| 67 |