--- /dev/null
+/* c-strcasestr.c -- case insensitive substring search in C locale
+ Copyright (C) 2005 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2005.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification. */
+#include "c-strcasestr.h"
+
+#include <stddef.h>
+
+#include "c-ctype.h"
+
+/* Find the first occurrence of NEEDLE in HAYSTACK, using case-insensitive
+ comparison.
+ Note: This function may, in multibyte locales, return success even if
+ strlen (haystack) < strlen (needle) ! */
+char *
+c_strcasestr (const char *haystack, const char *needle)
+{
+ /* Be careful not to look at the entire extent of haystack or needle
+ until needed. This is useful because of these two cases:
+ - haystack may be very long, and a match of needle found early,
+ - needle may be very long, and not even a short initial segment of
+ needle may be found in haystack. */
+ if (*needle != '\0')
+ {
+ /* Speed up the following searches of needle by caching its first
+ character. */
+ unsigned char b = c_tolower ((unsigned char) *needle);
+
+ needle++;
+ for (;; haystack++)
+ {
+ if (*haystack == '\0')
+ /* No match. */
+ return NULL;
+ if (c_tolower ((unsigned char) *haystack) == b)
+ /* The first character matches. */
+ {
+ const char *rhaystack = haystack + 1;
+ const char *rneedle = needle;
+
+ for (;; rhaystack++, rneedle++)
+ {
+ if (*rneedle == '\0')
+ /* Found a match. */
+ return (char *) haystack;
+ if (*rhaystack == '\0')
+ /* No match. */
+ return NULL;
+ if (c_tolower ((unsigned char) *rhaystack)
+ != c_tolower ((unsigned char) *rneedle))
+ /* Nothing in this round. */
+ break;
+ }
+ }
+ }
+ }
+ else
+ return (char *) haystack;
+}
--- /dev/null
+/* Case-insensitive searching in a string in C locale.
+ Copyright (C) 2005 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#ifndef C_STRCASESTR_H
+#define C_STRCASESTR_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* Find the first occurrence of NEEDLE in HAYSTACK, using case-insensitive
+ comparison. */
+extern char *c_strcasestr (const char *haystack, const char *needle);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* C_STRCASESTR_H */