xref: /freebsd/sys/libkern/scanc.c (revision ab0de15baf7234734b1b64c3145cd36f867c98ea)
1df8bae1dSRodney W. Grimes /*-
2df8bae1dSRodney W. Grimes  * Copyright (c) 1992, 1993
3df8bae1dSRodney W. Grimes  *	The Regents of the University of California.  All rights reserved.
4df8bae1dSRodney W. Grimes  *
5df8bae1dSRodney W. Grimes  * Redistribution and use in source and binary forms, with or without
6df8bae1dSRodney W. Grimes  * modification, are permitted provided that the following conditions
7df8bae1dSRodney W. Grimes  * are met:
8df8bae1dSRodney W. Grimes  * 1. Redistributions of source code must retain the above copyright
9df8bae1dSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer.
10df8bae1dSRodney W. Grimes  * 2. Redistributions in binary form must reproduce the above copyright
11df8bae1dSRodney W. Grimes  *    notice, this list of conditions and the following disclaimer in the
12df8bae1dSRodney W. Grimes  *    documentation and/or other materials provided with the distribution.
13df8bae1dSRodney W. Grimes  * 3. All advertising materials mentioning features or use of this software
14df8bae1dSRodney W. Grimes  *    must display the following acknowledgement:
15df8bae1dSRodney W. Grimes  *	This product includes software developed by the University of
16df8bae1dSRodney W. Grimes  *	California, Berkeley and its contributors.
17df8bae1dSRodney W. Grimes  * 4. Neither the name of the University nor the names of its contributors
18df8bae1dSRodney W. Grimes  *    may be used to endorse or promote products derived from this software
19df8bae1dSRodney W. Grimes  *    without specific prior written permission.
20df8bae1dSRodney W. Grimes  *
21df8bae1dSRodney W. Grimes  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22df8bae1dSRodney W. Grimes  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23df8bae1dSRodney W. Grimes  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24df8bae1dSRodney W. Grimes  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25df8bae1dSRodney W. Grimes  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26df8bae1dSRodney W. Grimes  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27df8bae1dSRodney W. Grimes  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28df8bae1dSRodney W. Grimes  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29df8bae1dSRodney W. Grimes  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30df8bae1dSRodney W. Grimes  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31df8bae1dSRodney W. Grimes  * SUCH DAMAGE.
32df8bae1dSRodney W. Grimes  *
33df8bae1dSRodney W. Grimes  *	@(#)scanc.c	8.1 (Berkeley) 6/10/93
34df8bae1dSRodney W. Grimes  */
35df8bae1dSRodney W. Grimes 
36ab0de15bSDavid E. O'Brien #include <sys/cdefs.h>
37ab0de15bSDavid E. O'Brien __FBSDID("$FreeBSD$");
38ab0de15bSDavid E. O'Brien 
395edd0e15SPoul-Henning Kamp #include <sys/libkern.h>
40df8bae1dSRodney W. Grimes 
41df8bae1dSRodney W. Grimes int
42df8bae1dSRodney W. Grimes scanc(size, cp, table, mask0)
43df8bae1dSRodney W. Grimes 	u_int size;
44e0c95ed9SBruce Evans 	register const u_char *cp, table[];
45df8bae1dSRodney W. Grimes 	int mask0;
46df8bae1dSRodney W. Grimes {
47e0c95ed9SBruce Evans 	register const u_char *end;
48df8bae1dSRodney W. Grimes 	register u_char mask;
49df8bae1dSRodney W. Grimes 
50df8bae1dSRodney W. Grimes 	mask = mask0;
515182dcbeSBruce Evans 	for (end = &cp[size]; cp < end; ++cp) {
525182dcbeSBruce Evans 		/*
535182dcbeSBruce Evans 		 * gcc-2.6.3 generates poor (un)sign extension code on i386's.
545182dcbeSBruce Evans 		 * The cast to volatile should have no effect, but in fact it
555182dcbeSBruce Evans 		 * improves the code on i386's.
565182dcbeSBruce Evans 		 */
57e0c95ed9SBruce Evans 		if (table[*(volatile const u_char *)cp] & mask)
585182dcbeSBruce Evans 			break;
595182dcbeSBruce Evans 	}
60df8bae1dSRodney W. Grimes 	return (end - cp);
61df8bae1dSRodney W. Grimes }
62