projects / unix-history / blame
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1 | /* |
| 2 | * Copyright (c) 1989 The Regents of the University of California. | |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * This code is derived from software contributed to Berkeley by | |
| 6 | * Roger L. Snyder. | |
| 7 | * | |
| 8 | * Redistribution and use in source and binary forms are permitted | |
| 9 | * provided that the above copyright notice and this paragraph are | |
| 10 | * duplicated in all such forms and that any documentation, | |
| 11 | * advertising materials, and other materials related to such | |
| 12 | * distribution and use acknowledge that the software was developed | |
| 13 | * by the University of California, Berkeley. The name of the | |
| 14 | * University may not be used to endorse or promote products derived | |
| 15 | * from this software without specific prior written permission. | |
| 16 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
| 17 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
| 18 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
| 19 | */ | |
| 20 | ||
| 21 | #if defined(LIBC_SCCS) && !defined(lint) | |
| 8190f343 | 22 | static char sccsid[] = "@(#)lsearch.c 5.2 (Berkeley) %G%"; |
| d2601b5f KB |
23 | #endif /* LIBC_SCCS and not lint */ |
| 24 | ||
| 25 | #include <sys/types.h> | |
| 26 | #include <unistd.h> | |
| 27 | ||
| 28 | char *linear_base(); | |
| 29 | ||
| 30 | char * | |
| 31 | lsearch(key, base, nelp, width, compar) | |
| 32 | char *key, *base; | |
| 33 | u_int *nelp, width; | |
| 34 | int (*compar)(); | |
| 35 | { | |
| 36 | return(linear_base(key, base, nelp, width, compar, 1)); | |
| 37 | } | |
| 38 | ||
| 39 | char * | |
| 40 | lfind(key, base, nelp, width, compar) | |
| 41 | char *key, *base; | |
| 42 | u_int *nelp, width; | |
| 43 | int (*compar)(); | |
| 44 | { | |
| 45 | return(linear_base(key, base, nelp, width, compar, 0)); | |
| 46 | } | |
| 47 | ||
| 48 | static char * | |
| 49 | linear_base(key, base, nelp, width, compar, add_flag) | |
| 50 | char *key, *base; | |
| 51 | u_int *nelp, width; | |
| 52 | int (*compar)(), add_flag; | |
| 53 | { | |
| 54 | register char *element, *end; | |
| 55 | ||
| 56 | end = base + *nelp * width; | |
| 57 | for (element = base; element < end; element += width) | |
| 58 | if (!compar(element, key)) /* key found */ | |
| 59 | return(element); | |
| 60 | ||
| 61 | if (!add_flag) /* key not found */ | |
| 62 | return(NULL); | |
| 63 | ||
| 64 | /* | |
| 65 | * The UNIX System User's Manual, 1986 edition claims that | |
| 66 | * a NULL pointer is returned by lsearch with errno set | |
| 67 | * appropriately, if there is not enough room in the table | |
| 68 | * to add a new item. This can't be done as none of these | |
| 69 | * routines have any method of determining the size of the | |
| 70 | * table. This comment was isn't in the 1986-87 System V | |
| 71 | * manual. | |
| 72 | */ | |
| 73 | ++*nelp; | |
| 74 | bcopy(key, end, (int)width); | |
| 75 | return(end); | |
| 76 | } |