Complete last ChangeLog entry.

[gnulib.git] / m4 / strcasestr.m4

diff --git a/m4/strcasestr.m4 b/m4/strcasestr.m4
index 4f94375..6e940bc 100644 (file)
--- a/m4/strcasestr.m4
+++ b/m4/strcasestr.m4
@@ -1,19 +1,28 @@
-# strcasestr.m4 serial 9
-dnl Copyright (C) 2005, 2007, 2008 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.
 
-dnl Check that strcasestr is present.
+dnl Check that strcasestr is present and works.
 AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
 [
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+
   dnl Persuade glibc <string.h> to declare strcasestr().
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 
-  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
-  AC_REPLACE_FUNCS([strcasestr])
+  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
@@ -22,10 +31,11 @@ dnl Additionally, check that strcasestr is efficient.
 AC_DEFUN([gl_FUNC_STRCASESTR],
 [
   AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE])
-  if test $ac_cv_func_strcasestr = yes; then
+  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 */
@@ -35,26 +45,46 @@ AC_DEFUN([gl_FUNC_STRCASESTR],
     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);
+        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 pessimistically assume the worst, since even glibc 2.6.1
-       dnl has quadratic complexity in its strcasestr
-       gl_cv_func_strcasestr_linear="guessing no"])])
+        [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