/* c-strcasestr.c -- case insensitive substring search in C locale
- Copyright (C) 2005-2006 Free Software Foundation, Inc.
+ Copyright (C) 2005-2014 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2005.
- This program is free software; you can redistribute it and/or modify
+ 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.
+ the Free Software Foundation; either version 3 of the License, 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
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "c-strcasestr.h"
-#include <stddef.h>
+#include <stdbool.h>
+#include <string.h>
#include "c-ctype.h"
+#include "c-strcase.h"
+
+/* Two-Way algorithm. */
+#define RETURN_TYPE char *
+#define AVAILABLE(h, h_l, j, n_l) \
+ (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \
+ && ((h_l) = (j) + (n_l)))
+#define CANON_ELEMENT c_tolower
+#define CMP_FUNC(p1, p2, l) \
+ c_strncasecmp ((const char *) (p1), (const char *) (p2), l)
+#include "str-two-way.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) ! */
+ comparison from the C locale, regardless of the current locale. */
char *
-c_strcasestr (const char *haystack, const char *needle)
+c_strcasestr (const char *haystack_start, const char *needle_start)
{
- /* 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);
+ const char *haystack = haystack_start;
+ const char *needle = needle_start;
+ size_t needle_len; /* Length of NEEDLE. */
+ size_t haystack_len; /* Known minimum length of HAYSTACK. */
+ bool ok = true; /* True if NEEDLE is prefix of HAYSTACK. */
- 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;
+ /* Determine length of NEEDLE, and in the process, make sure
+ HAYSTACK is at least as long (no point processing all of a long
+ NEEDLE if HAYSTACK is too short). */
+ while (*haystack && *needle)
+ ok &= (c_tolower ((unsigned char) *haystack++)
+ == c_tolower ((unsigned char) *needle++));
+ if (*needle)
+ return NULL;
+ if (ok)
+ return (char *) haystack_start;
+ needle_len = needle - needle_start;
+ haystack = haystack_start + 1;
+ haystack_len = needle_len - 1;
- 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;
+ /* Perform the search. Abstract memory is considered to be an array
+ of 'unsigned char' values, not an array of 'char' values. See
+ ISO C 99 section 6.2.6.1. */
+ if (needle_len < LONG_NEEDLE_THRESHOLD)
+ return two_way_short_needle ((const unsigned char *) haystack,
+ haystack_len,
+ (const unsigned char *) needle_start,
+ needle_len);
+ return two_way_long_needle ((const unsigned char *) haystack, haystack_len,
+ (const unsigned char *) needle_start,
+ needle_len);
}
+
+#undef LONG_NEEDLE_THRESHOLD