1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #if defined(LIBC_SCCS) && !defined(lint) 19 static char sccsid[] = "@(#)bsearch.c 5.1 (Berkeley) 10/14/89"; 20 #endif /* LIBC_SCCS and not lint */ 21 22 #include <sys/types.h> 23 #include <stdio.h> 24 25 char * 26 bsearch(key, base, nmemb, size, compar) 27 register char *key, *base; 28 size_t nmemb; 29 register size_t size; 30 register int (*compar)(); 31 { 32 register int bottom, middle, result, top; 33 register char *p; 34 35 for (bottom = 0, top = nmemb - 1; bottom <= top;) { 36 middle = (bottom + top) >> 1; 37 p = base + middle * size; 38 if (!(result = (*compar)(key, p))) 39 return(p); 40 if (result > 0) 41 bottom = middle + 1; 42 else 43 top = middle - 1; 44 } 45 return(NULL); 46 } 47