-# strcasestr.m4 serial 4
-dnl Copyright (C) 2005, 2007 Free Software Foundation, Inc.
+# strcasestr.m4 serial 13
+dnl Copyright (C) 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
-AC_DEFUN([gl_FUNC_STRCASESTR],
+dnl Check that strcasestr is present and works.
+AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
[
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
- dnl No known system has a strcasestr() function that works correctly in
- dnl multibyte locales. Therefore we use our version always.
- AC_LIBOBJ(strcasestr)
- REPLACE_STRCASESTR=1
- gl_PREREQ_STRCASESTR
-])
+
+ dnl Persuade glibc <string.h> to declare strcasestr().
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+ AC_REQUIRE([gl_FUNC_MEMCHR])
+ AC_CHECK_FUNCS([strcasestr])
+ if test $ac_cv_func_strcasestr = no; then
+ HAVE_STRCASESTR=0
+ else
+ if test "$gl_cv_func_memchr_works" != yes; then
+ REPLACE_STRCASESTR=1
+ fi
+ fi
+ if test $HAVE_STRCASESTR = 0 || test $REPLACE_STRCASESTR = 1; then
+ AC_LIBOBJ([strcasestr])
+ gl_PREREQ_STRCASESTR
+ fi
+]) # gl_FUNC_STRCASESTR_SIMPLE
+
+dnl Additionally, check that strcasestr is efficient.
+AC_DEFUN([gl_FUNC_STRCASESTR],
+[
+ AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
+ if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then
+ AC_CACHE_CHECK([whether strcasestr works in linear time],
+ [gl_cv_func_strcasestr_linear],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <signal.h> /* for signal */
+#include <string.h> /* for memmem */
+#include <stdlib.h> /* for malloc */
+#include <unistd.h> /* for alarm */
+]], [[size_t m = 1000000;
+ char *haystack = (char *) malloc (2 * m + 2);
+ char *needle = (char *) malloc (m + 2);
+ void *result = 0;
+ /* Failure to compile this test due to missing alarm is okay,
+ since all such platforms (mingw) also lack strcasestr. */
+ signal (SIGALRM, SIG_DFL);
+ alarm (5);
+ /* Check for quadratic performance. */
+ if (haystack && needle)
+ {
+ memset (haystack, 'A', 2 * m);
+ haystack[2 * m] = 'B';
+ haystack[2 * m + 1] = 0;
+ memset (needle, 'A', m);
+ needle[m] = 'B';
+ needle[m + 1] = 0;
+ result = strcasestr (haystack, needle);
+ }
+ return !result;]])],
+ [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
+ [dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a
+ dnl strcasestr that works in linear time.
+ AC_EGREP_CPP([Lucky user],
+ [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)
+ Lucky user
+ #endif
+#endif
+#ifdef __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+ Lucky user
+ #endif
+#endif
+ ],
+ [gl_cv_func_strcasestr_linear=yes],
+ [gl_cv_func_strcasestr_linear="guessing no"])
+ ])
+ ])
+ if test "$gl_cv_func_strcasestr_linear" != yes; then
+ REPLACE_STRCASESTR=1
+ AC_LIBOBJ([strcasestr])
+ gl_PREREQ_STRCASESTR
+ fi
+ fi
+]) # gl_FUNC_STRCASESTR
# Prerequisites of lib/strcasestr.c.
AC_DEFUN([gl_PREREQ_STRCASESTR], [
- AC_REQUIRE([gl_FUNC_MBRTOWC])
:
])