libc -- string: strspn should return 0 for empty match strings, not string len.
[dragonfly.git] / lib / libc / string / strspn.c
CommitLineData
b638a263
SW
1/*-
2 * Copyright (c) 2005 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Andreas Hauser <andy-dragonfly@splashground.de>
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 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $DragonFly: src/lib/libc/string/strspn.c,v 1.5 2008/05/15 03:48:58 dillon Exp $
35 */
36
37#include <assert.h>
38#include <limits.h>
39#include <stdbool.h>
40#include <string.h>
41
42/*
43 * Longest initial segment of string *str, containing any chars from *chars.
44 */
45size_t
46strspn(const char *str, const char *chars)
47{
48 const char *s;
49 bool charset[UCHAR_MAX + 1];
50
51 _DIAGASSERT(str != NULL);
52 _DIAGASSERT(chars != NULL);
53
54 if(*str == '\0')
55 return 0;
56 if(*chars == '\0')
ac343b62 57 return 0;
b638a263
SW
58
59 memset(charset, false, sizeof(charset));
60 for( ; *chars != '\0'; chars++)
61 charset[*(const unsigned char *)chars] = true;
62
63 for(s = str; charset[*(const unsigned char *)s] == true; s++)
64 /* NOTHING */
65 ;
66
67 return (s - str);
68}