-/* Searching in a string.
- Copyright (C) 2005 Free Software Foundation, Inc.
- Written by Bruno Haible <bruno@clisp.org>, 2005.
+/* Copyright (C) 1991-1994, 1996-1998, 2000, 2004, 2007-2014 Free Software
+ Foundation, Inc.
+ This file is part of the GNU C Library.
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
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. */
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, see <http://www.gnu.org/licenses/>. */
-#if HAVE_CONFIG_H
+/* This particular implementation was written by Eric Blake, 2008. */
+
+#ifndef _LIBC
# include <config.h>
#endif
-/* Specification. */
-#include "strstr.h"
+/* Specification of strstr. */
+#include <string.h>
+
+#include <stdbool.h>
-#if HAVE_MBRTOWC
-# include "mbuiter.h"
+#ifndef _LIBC
+# define __builtin_expect(expr, val) (expr)
#endif
-/* Find the first occurrence of NEEDLE in HAYSTACK. */
+#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)))
+#include "str-two-way.h"
+
+/* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK
+ if NEEDLE is empty, otherwise NULL if NEEDLE is not found in
+ HAYSTACK. */
char *
-strstr (const char *haystack, const char *needle)
+strstr (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 HAVE_MBRTOWC
- if (MB_CUR_MAX > 1)
- {
- mbui_iterator_t iter_needle;
-
- mbui_init (iter_needle, needle);
- if (mbui_avail (iter_needle))
- {
- mbui_iterator_t iter_haystack;
-
- mbui_init (iter_haystack, haystack);
- for (;; mbui_advance (iter_haystack))
- {
- if (!mbui_avail (iter_haystack))
- /* No match. */
- return NULL;
+ 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. */
- if (mb_equal (mbui_cur (iter_haystack), mbui_cur (iter_needle)))
- /* The first character matches. */
- {
- mbui_iterator_t rhaystack;
- mbui_iterator_t rneedle;
+ /* 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 &= *haystack++ == *needle++;
+ if (*needle)
+ return NULL;
+ if (ok)
+ return (char *) haystack_start;
- memcpy (&rhaystack, &iter_haystack, sizeof (mbui_iterator_t));
- mbui_advance (rhaystack);
+ /* Reduce the size of haystack using strchr, since it has a smaller
+ linear coefficient than the Two-Way algorithm. */
+ needle_len = needle - needle_start;
+ haystack = strchr (haystack_start + 1, *needle_start);
+ if (!haystack || __builtin_expect (needle_len == 1, 0))
+ return (char *) haystack;
+ needle -= needle_len;
+ haystack_len = (haystack > haystack_start + needle_len ? 1
+ : needle_len + haystack_start - haystack);
- mbui_init (rneedle, needle);
- if (!mbui_avail (rneedle))
- abort ();
- mbui_advance (rneedle);
-
- for (;; mbui_advance (rhaystack), mbui_advance (rneedle))
- {
- if (!mbui_avail (rneedle))
- /* Found a match. */
- return (char *) mbui_cur_ptr (iter_haystack);
- if (!mbui_avail (rhaystack))
- /* No match. */
- return NULL;
- if (!mb_equal (mbui_cur (rhaystack), mbui_cur (rneedle)))
- /* Nothing in this round. */
- break;
- }
- }
- }
- }
- else
- return (char *) haystack;
- }
- else
-#endif
- {
- if (*needle != '\0')
- {
- /* Speed up the following searches of needle by caching its first
- character. */
- char b = *needle++;
-
- for (;; haystack++)
- {
- if (*haystack == '\0')
- /* No match. */
- return NULL;
- if (*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 (*rhaystack != *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, needle_len);
+ return two_way_long_needle ((const unsigned char *) haystack, haystack_len,
+ (const unsigned char *) needle, needle_len);
}
+
+#undef LONG_NEEDLE_THRESHOLD
projects / gnulib.git / blobdiff