1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/libkern.h>
33#include <sys/types.h>
34#include <sys/limits.h>
35
36#define	IDX(c)	((u_char)(c) / LONG_BIT)
37#define	BIT(c)	((u_long)1 << ((u_char)(c) % LONG_BIT))
38
39size_t
40strcspn(const char * __restrict s, const char * __restrict charset)
41{
42	/*
43	 * NB: idx and bit are temporaries whose use causes gcc 3.4.2 to
44	 * generate better code.  Without them, gcc gets a little confused.
45	 */
46	const char *s1;
47	u_long bit;
48	u_long tbl[(UCHAR_MAX + 1) / LONG_BIT];
49	int idx;
50
51	if(*s == '\0')
52		return (0);
53
54#if LONG_BIT == 64	/* always better to unroll on 64-bit architectures */
55	tbl[0] = 1;
56	tbl[3] = tbl[2] = tbl[1] = 0;
57#else
58	for (tbl[0] = idx = 1; idx < sizeof(tbl) / sizeof(tbl[0]); idx++)
59		tbl[idx] = 0;
60#endif
61	for (; *charset != '\0'; charset++) {
62		idx = IDX(*charset);
63		bit = BIT(*charset);
64		tbl[idx] |= bit;
65	}
66
67	for(s1 = s; ; s1++) {
68		idx = IDX(*s1);
69		bit = BIT(*s1);
70		if ((tbl[idx] & bit) != 0)
71			break;
72	}
73	return (s1 - s);
74}
75