xref: /onnv-gate/usr/src/lib/libbc/libc/gen/common/lfind.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*      Copyright (c) 1984 AT&T */
23*0Sstevel@tonic-gate /*        All Rights Reserved   */
24*0Sstevel@tonic-gate 
25*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"  /* from S5R2 1.1 */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate /*LINTLIBRARY*/
28*0Sstevel@tonic-gate /*
29*0Sstevel@tonic-gate  * Linear search algorithm, generalized from Knuth (6.1) Algorithm Q.
30*0Sstevel@tonic-gate  *
31*0Sstevel@tonic-gate  * This version no longer has anything to do with Knuth's Algorithm Q,
32*0Sstevel@tonic-gate  * which first copies the new element into the table, then looks for it.
33*0Sstevel@tonic-gate  * The assumption there was that the cost of checking for the end of the
34*0Sstevel@tonic-gate  * table before each comparison outweighed the cost of the comparison, which
35*0Sstevel@tonic-gate  * isn't true when an arbitrary comparison function must be called and when the
36*0Sstevel@tonic-gate  * copy itself takes a significant number of cycles.
37*0Sstevel@tonic-gate  * Actually, it has now reverted to Algorithm S, which is "simpler."
38*0Sstevel@tonic-gate  */
39*0Sstevel@tonic-gate 
40*0Sstevel@tonic-gate typedef char *POINTER;
41*0Sstevel@tonic-gate extern POINTER memcpy();
42*0Sstevel@tonic-gate 
43*0Sstevel@tonic-gate POINTER
lfind(key,base,nelp,width,compar)44*0Sstevel@tonic-gate lfind(key, base, nelp, width, compar)
45*0Sstevel@tonic-gate register POINTER key;		/* Key to be located */
46*0Sstevel@tonic-gate register POINTER base;		/* Beginning of table */
47*0Sstevel@tonic-gate unsigned *nelp;			/* Pointer to current table size */
48*0Sstevel@tonic-gate register unsigned width;	/* Width of an element (bytes) */
49*0Sstevel@tonic-gate int (*compar)();		/* Comparison function */
50*0Sstevel@tonic-gate {
51*0Sstevel@tonic-gate 	register POINTER next = base + *nelp * width;	/* End of table */
52*0Sstevel@tonic-gate 
53*0Sstevel@tonic-gate 	for ( ; base < next; base += width)
54*0Sstevel@tonic-gate 		if ((*compar)(key, base) == 0)
55*0Sstevel@tonic-gate 			return (base);	/* Key found */
56*0Sstevel@tonic-gate 	return (POINTER)0;
57*0Sstevel@tonic-gate }
58