|
6360
|
1 /* c-strcasestr.c -- case insensitive substring search in C locale |
|
|
2 Copyright (C) 2005 Free Software Foundation, Inc. |
|
|
3 Written by Bruno Haible <bruno@clisp.org>, 2005. |
|
|
4 |
|
|
5 This program is free software; you can redistribute it and/or modify |
|
|
6 it under the terms of the GNU General Public License as published by |
|
|
7 the Free Software Foundation; either version 2, or (at your option) |
|
|
8 any later version. |
|
|
9 |
|
|
10 This program is distributed in the hope that it will be useful, |
|
|
11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
|
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
|
13 GNU General Public License for more details. |
|
|
14 |
|
|
15 You should have received a copy of the GNU General Public License |
|
|
16 along with this program; if not, write to the Free Software Foundation, |
|
|
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ |
|
|
18 |
|
|
19 #ifdef HAVE_CONFIG_H |
|
|
20 # include <config.h> |
|
|
21 #endif |
|
|
22 |
|
|
23 /* Specification. */ |
|
|
24 #include "c-strcasestr.h" |
|
|
25 |
|
|
26 #include <stddef.h> |
|
|
27 |
|
|
28 #include "c-ctype.h" |
|
|
29 |
|
|
30 /* Find the first occurrence of NEEDLE in HAYSTACK, using case-insensitive |
|
|
31 comparison. |
|
|
32 Note: This function may, in multibyte locales, return success even if |
|
|
33 strlen (haystack) < strlen (needle) ! */ |
|
|
34 char * |
|
|
35 c_strcasestr (const char *haystack, const char *needle) |
|
|
36 { |
|
|
37 /* Be careful not to look at the entire extent of haystack or needle |
|
|
38 until needed. This is useful because of these two cases: |
|
|
39 - haystack may be very long, and a match of needle found early, |
|
|
40 - needle may be very long, and not even a short initial segment of |
|
|
41 needle may be found in haystack. */ |
|
|
42 if (*needle != '\0') |
|
|
43 { |
|
|
44 /* Speed up the following searches of needle by caching its first |
|
|
45 character. */ |
|
|
46 unsigned char b = c_tolower ((unsigned char) *needle); |
|
|
47 |
|
|
48 needle++; |
|
|
49 for (;; haystack++) |
|
|
50 { |
|
|
51 if (*haystack == '\0') |
|
|
52 /* No match. */ |
|
|
53 return NULL; |
|
|
54 if (c_tolower ((unsigned char) *haystack) == b) |
|
|
55 /* The first character matches. */ |
|
|
56 { |
|
|
57 const char *rhaystack = haystack + 1; |
|
|
58 const char *rneedle = needle; |
|
|
59 |
|
|
60 for (;; rhaystack++, rneedle++) |
|
|
61 { |
|
|
62 if (*rneedle == '\0') |
|
|
63 /* Found a match. */ |
|
|
64 return (char *) haystack; |
|
|
65 if (*rhaystack == '\0') |
|
|
66 /* No match. */ |
|
|
67 return NULL; |
|
|
68 if (c_tolower ((unsigned char) *rhaystack) |
|
|
69 != c_tolower ((unsigned char) *rneedle)) |
|
|
70 /* Nothing in this round. */ |
|
|
71 break; |
|
|
72 } |
|
|
73 } |
|
|
74 } |
|
|
75 } |
|
|
76 else |
|
|
77 return (char *) haystack; |
|
|
78 } |
