xref: /illumos-gate/usr/src/boot/libsa/string/strcspn.c (revision 22028508)
1199767f8SToomas Soome /*-
2199767f8SToomas Soome  * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
3199767f8SToomas Soome  * All rights reserved.
4199767f8SToomas Soome  *
5199767f8SToomas Soome  * Redistribution and use in source and binary forms, with or without
6199767f8SToomas Soome  * modification, are permitted provided that the following conditions
7199767f8SToomas Soome  * are met:
8199767f8SToomas Soome  * 1. Redistributions of source code must retain the above copyright
9199767f8SToomas Soome  *    notice, this list of conditions and the following disclaimer.
10199767f8SToomas Soome  * 2. Redistributions in binary form must reproduce the above copyright
11199767f8SToomas Soome  *    notice, this list of conditions and the following disclaimer in the
12199767f8SToomas Soome  *    documentation and/or other materials provided with the distribution.
13199767f8SToomas Soome  *
14199767f8SToomas Soome  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15199767f8SToomas Soome  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16199767f8SToomas Soome  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17199767f8SToomas Soome  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18199767f8SToomas Soome  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19199767f8SToomas Soome  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20199767f8SToomas Soome  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21199767f8SToomas Soome  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22199767f8SToomas Soome  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23199767f8SToomas Soome  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24199767f8SToomas Soome  * SUCH DAMAGE.
25199767f8SToomas Soome  */
26199767f8SToomas Soome 
27199767f8SToomas Soome #include <sys/cdefs.h>
28199767f8SToomas Soome __FBSDID("$FreeBSD$");
29199767f8SToomas Soome 
30199767f8SToomas Soome #include <sys/types.h>
31199767f8SToomas Soome #include <limits.h>
32199767f8SToomas Soome #include <string.h>
33199767f8SToomas Soome 
34199767f8SToomas Soome #define	IDX(c)	((u_char)(c) / LONG_BIT)
35199767f8SToomas Soome #define	BIT(c)	((u_long)1 << ((u_char)(c) % LONG_BIT))
36199767f8SToomas Soome 
37199767f8SToomas Soome size_t
strcspn(const char * s,const char * charset)38199767f8SToomas Soome strcspn(const char *s, const char *charset)
39199767f8SToomas Soome {
40199767f8SToomas Soome 	/*
41199767f8SToomas Soome 	 * NB: idx and bit are temporaries whose use causes gcc 3.4.2 to
42199767f8SToomas Soome 	 * generate better code.  Without them, gcc gets a little confused.
43199767f8SToomas Soome 	 */
44199767f8SToomas Soome 	const char *s1;
45199767f8SToomas Soome 	u_long bit;
46199767f8SToomas Soome 	u_long tbl[(UCHAR_MAX + 1) / LONG_BIT];
47199767f8SToomas Soome 	int idx;
48199767f8SToomas Soome 
49199767f8SToomas Soome 	if(*s == '\0')
50199767f8SToomas Soome 		return (0);
51199767f8SToomas Soome 
52199767f8SToomas Soome #if LONG_BIT == 64	/* always better to unroll on 64-bit architectures */
53199767f8SToomas Soome 	tbl[0] = 1;
54199767f8SToomas Soome 	tbl[3] = tbl[2] = tbl[1] = 0;
55199767f8SToomas Soome #else
56199767f8SToomas Soome 	for (tbl[0] = idx = 1; idx < sizeof(tbl) / sizeof(tbl[0]); idx++)
57199767f8SToomas Soome 		tbl[idx] = 0;
58199767f8SToomas Soome #endif
59199767f8SToomas Soome 	for (; *charset != '\0'; charset++) {
60199767f8SToomas Soome 		idx = IDX(*charset);
61199767f8SToomas Soome 		bit = BIT(*charset);
62199767f8SToomas Soome 		tbl[idx] |= bit;
63199767f8SToomas Soome 	}
64199767f8SToomas Soome 
65199767f8SToomas Soome 	for(s1 = s; ; s1++) {
66199767f8SToomas Soome 		idx = IDX(*s1);
67199767f8SToomas Soome 		bit = BIT(*s1);
68199767f8SToomas Soome 		if ((tbl[idx] & bit) != 0)
69199767f8SToomas Soome 			break;
70199767f8SToomas Soome 	}
71199767f8SToomas Soome 	return (s1 - s);
72199767f8SToomas Soome }
73