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Diffstat (limited to 'gl/strcasestr.c')
-rw-r--r-- | gl/strcasestr.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/gl/strcasestr.c b/gl/strcasestr.c new file mode 100644 index 0000000..53474a4 --- /dev/null +++ b/gl/strcasestr.c | |||
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1 | /* Case-insensitive searching in a string. | ||
2 | Copyright (C) 2005-2013 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 3, 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, see <http://www.gnu.org/licenses/>. */ | ||
17 | |||
18 | #include <config.h> | ||
19 | |||
20 | /* Specification. */ | ||
21 | #include <string.h> | ||
22 | |||
23 | #include <ctype.h> | ||
24 | #include <stdbool.h> | ||
25 | #include <strings.h> | ||
26 | |||
27 | #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch)) | ||
28 | |||
29 | /* Two-Way algorithm. */ | ||
30 | #define RETURN_TYPE char * | ||
31 | #define AVAILABLE(h, h_l, j, n_l) \ | ||
32 | (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \ | ||
33 | && ((h_l) = (j) + (n_l))) | ||
34 | #define CANON_ELEMENT(c) TOLOWER (c) | ||
35 | #define CMP_FUNC(p1, p2, l) \ | ||
36 | strncasecmp ((const char *) (p1), (const char *) (p2), l) | ||
37 | #include "str-two-way.h" | ||
38 | |||
39 | /* Find the first occurrence of NEEDLE in HAYSTACK, using | ||
40 | case-insensitive comparison. This function gives unspecified | ||
41 | results in multibyte locales. */ | ||
42 | char * | ||
43 | strcasestr (const char *haystack_start, const char *needle_start) | ||
44 | { | ||
45 | const char *haystack = haystack_start; | ||
46 | const char *needle = needle_start; | ||
47 | size_t needle_len; /* Length of NEEDLE. */ | ||
48 | size_t haystack_len; /* Known minimum length of HAYSTACK. */ | ||
49 | bool ok = true; /* True if NEEDLE is prefix of HAYSTACK. */ | ||
50 | |||
51 | /* Determine length of NEEDLE, and in the process, make sure | ||
52 | HAYSTACK is at least as long (no point processing all of a long | ||
53 | NEEDLE if HAYSTACK is too short). */ | ||
54 | while (*haystack && *needle) | ||
55 | { | ||
56 | ok &= (TOLOWER ((unsigned char) *haystack) | ||
57 | == TOLOWER ((unsigned char) *needle)); | ||
58 | haystack++; | ||
59 | needle++; | ||
60 | } | ||
61 | if (*needle) | ||
62 | return NULL; | ||
63 | if (ok) | ||
64 | return (char *) haystack_start; | ||
65 | needle_len = needle - needle_start; | ||
66 | haystack = haystack_start + 1; | ||
67 | haystack_len = needle_len - 1; | ||
68 | |||
69 | /* Perform the search. Abstract memory is considered to be an array | ||
70 | of 'unsigned char' values, not an array of 'char' values. See | ||
71 | ISO C 99 section 6.2.6.1. */ | ||
72 | if (needle_len < LONG_NEEDLE_THRESHOLD) | ||
73 | return two_way_short_needle ((const unsigned char *) haystack, | ||
74 | haystack_len, | ||
75 | (const unsigned char *) needle_start, | ||
76 | needle_len); | ||
77 | return two_way_long_needle ((const unsigned char *) haystack, haystack_len, | ||
78 | (const unsigned char *) needle_start, | ||
79 | needle_len); | ||
80 | } | ||
81 | |||
82 | #undef LONG_NEEDLE_THRESHOLD | ||