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224c7076 A |
1 | /*- |
2 | * Copyright (c) 2005 David Schultz <das@FreeBSD.ORG> | |
3 | * All rights reserved. | |
e9ce8d39 A |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
e9ce8d39 | 13 | * |
224c7076 | 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
e9ce8d39 A |
15 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
16 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
224c7076 | 17 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
e9ce8d39 A |
18 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
19 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
20 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
22 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
23 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
24 | * SUCH DAMAGE. | |
25 | */ | |
26 | ||
9385eb3d | 27 | #include <sys/cdefs.h> |
224c7076 | 28 | __FBSDID("$FreeBSD: src/lib/libc/string/strspn.c,v 1.5 2005/04/02 18:52:44 das Exp $"); |
e9ce8d39 | 29 | |
224c7076 A |
30 | #include <sys/types.h> |
31 | #include <limits.h> | |
9385eb3d | 32 | #include <string.h> |
e9ce8d39 | 33 | |
224c7076 A |
34 | #define IDX(c) ((u_char)(c) / LONG_BIT) |
35 | #define BIT(c) ((u_long)1 << ((u_char)(c) % LONG_BIT)) | |
36 | ||
9385eb3d | 37 | size_t |
224c7076 | 38 | strspn(const char *s, const char *charset) |
e9ce8d39 | 39 | { |
9385eb3d | 40 | /* |
224c7076 A |
41 | * NB: idx and bit are temporaries whose use causes gcc 3.4.2 to |
42 | * generate better code. Without them, gcc gets a little confused. | |
9385eb3d | 43 | */ |
224c7076 A |
44 | const char *s1; |
45 | u_long bit; | |
46 | u_long tbl[(UCHAR_MAX + 1) / LONG_BIT]; | |
47 | int idx; | |
48 | ||
49 | if(*s == '\0') | |
50 | return (0); | |
51 | ||
52 | #if LONG_BIT == 64 /* always better to unroll on 64-bit architectures */ | |
53 | tbl[3] = tbl[2] = tbl[1] = tbl[0] = 0; | |
54 | #else | |
55 | for (idx = 0; idx < sizeof(tbl) / sizeof(tbl[0]); idx++) | |
56 | tbl[idx] = 0; | |
57 | #endif | |
58 | for (; *charset != '\0'; charset++) { | |
59 | idx = IDX(*charset); | |
60 | bit = BIT(*charset); | |
61 | tbl[idx] |= bit; | |
62 | } | |
63 | ||
64 | for(s1 = s; ; s1++) { | |
65 | idx = IDX(*s1); | |
66 | bit = BIT(*s1); | |
67 | if ((tbl[idx] & bit) == 0) | |
68 | break; | |
69 | } | |
70 | return (s1 - s); | |
e9ce8d39 | 71 | } |