xref: /dflybsd-src/lib/libc/string/strcspn.c (revision 86d7f5d305c6adaa56ff4582ece9859d73106103)
1*86d7f5d3SJohn Marino /*-
2*86d7f5d3SJohn Marino  * Copyright (c) 2005 The DragonFly Project.  All rights reserved.
3*86d7f5d3SJohn Marino  *
4*86d7f5d3SJohn Marino  * This code is derived from software contributed to The DragonFly Project
5*86d7f5d3SJohn Marino  * by Andreas Hauser <andy-dragonfly@splashground.de>
6*86d7f5d3SJohn Marino  *
7*86d7f5d3SJohn Marino  * Redistribution and use in source and binary forms, with or without
8*86d7f5d3SJohn Marino  * modification, are permitted provided that the following conditions
9*86d7f5d3SJohn Marino  * are met:
10*86d7f5d3SJohn Marino  *
11*86d7f5d3SJohn Marino  * 1. Redistributions of source code must retain the above copyright
12*86d7f5d3SJohn Marino  *    notice, this list of conditions and the following disclaimer.
13*86d7f5d3SJohn Marino  * 2. Redistributions in binary form must reproduce the above copyright
14*86d7f5d3SJohn Marino  *    notice, this list of conditions and the following disclaimer in
15*86d7f5d3SJohn Marino  *    the documentation and/or other materials provided with the
16*86d7f5d3SJohn Marino  *    distribution.
17*86d7f5d3SJohn Marino  * 3. Neither the name of The DragonFly Project nor the names of its
18*86d7f5d3SJohn Marino  *    contributors may be used to endorse or promote products derived
19*86d7f5d3SJohn Marino  *    from this software without specific, prior written permission.
20*86d7f5d3SJohn Marino  *
21*86d7f5d3SJohn Marino  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22*86d7f5d3SJohn Marino  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23*86d7f5d3SJohn Marino  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24*86d7f5d3SJohn Marino  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25*86d7f5d3SJohn Marino  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26*86d7f5d3SJohn Marino  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27*86d7f5d3SJohn Marino  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28*86d7f5d3SJohn Marino  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29*86d7f5d3SJohn Marino  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30*86d7f5d3SJohn Marino  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31*86d7f5d3SJohn Marino  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32*86d7f5d3SJohn Marino  * SUCH DAMAGE.
33*86d7f5d3SJohn Marino  *
34*86d7f5d3SJohn Marino  * $DragonFly: src/lib/libc/string/strcspn.c,v 1.5 2008/05/15 03:48:58 dillon Exp $
35*86d7f5d3SJohn Marino  */
36*86d7f5d3SJohn Marino 
37*86d7f5d3SJohn Marino #include <assert.h>
38*86d7f5d3SJohn Marino #include <limits.h>
39*86d7f5d3SJohn Marino #include <stdbool.h>
40*86d7f5d3SJohn Marino #include <string.h>
41*86d7f5d3SJohn Marino 
42*86d7f5d3SJohn Marino /*
43*86d7f5d3SJohn Marino  * Longest initial segment of string *str, not containing any chars from *chars.
44*86d7f5d3SJohn Marino  */
45*86d7f5d3SJohn Marino size_t
strcspn(const char * str,const char * chars)46*86d7f5d3SJohn Marino strcspn(const char *str, const char *chars)
47*86d7f5d3SJohn Marino {
48*86d7f5d3SJohn Marino         const char *s;
49*86d7f5d3SJohn Marino         bool charset[UCHAR_MAX + 1];
50*86d7f5d3SJohn Marino 
51*86d7f5d3SJohn Marino          _DIAGASSERT(str != NULL);
52*86d7f5d3SJohn Marino          _DIAGASSERT(chars != NULL);
53*86d7f5d3SJohn Marino 
54*86d7f5d3SJohn Marino         if(*str == '\0')
55*86d7f5d3SJohn Marino                 return 0;
56*86d7f5d3SJohn Marino         if(*chars == '\0')
57*86d7f5d3SJohn Marino                 return strlen(str);
58*86d7f5d3SJohn Marino 
59*86d7f5d3SJohn Marino         memset(charset, false, sizeof(charset));
60*86d7f5d3SJohn Marino         do
61*86d7f5d3SJohn Marino                 charset[*(const unsigned char *)chars] = true;
62*86d7f5d3SJohn Marino         while(*chars++ != '\0');
63*86d7f5d3SJohn Marino 
64*86d7f5d3SJohn Marino         for(s = str; charset[*(const unsigned char *)s] == false; s++)
65*86d7f5d3SJohn Marino                 /* NOTHING */
66*86d7f5d3SJohn Marino                 ;
67*86d7f5d3SJohn Marino 
68*86d7f5d3SJohn Marino         return (s - str);
69*86d7f5d3SJohn Marino }
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