maint: update copyright

[gnulib.git] / m4 / strcasestr.m4

diff --git a/m4/strcasestr.m4 b/m4/strcasestr.m4
index 61c348a..e2d87fe 100644 (file)
--- a/m4/strcasestr.m4
+++ b/m4/strcasestr.m4
@@ -1,21 +1,142 @@
-# strcasestr.m4 serial 4
-dnl Copyright (C) 2005, 2007 Free Software Foundation, Inc.
+# strcasestr.m4 serial 21
+dnl Copyright (C) 2005, 2007-2014 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
+    else
+      dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+      AC_CACHE_CHECK([whether strcasestr works],
+        [gl_cv_func_strcasestr_works_always],
+        [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for strcasestr */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!strcasestr (HAYSTACK, NEEDLE);
+      ]])],
+          [gl_cv_func_strcasestr_works_always=yes],
+          [gl_cv_func_strcasestr_works_always=no],
+          [dnl glibc 2.12 and cygwin 1.7.7 have a known bug.  uClibc is not
+           dnl affected, since it uses different source code for strcasestr
+           dnl than glibc.
+           dnl Assume that it works on all other platforms, even if it is not
+           dnl linear.
+           AC_EGREP_CPP([Lucky user],
+             [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
+     || defined __UCLIBC__
+  Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
+  Lucky user
+ #endif
+#else
+  Lucky user
+#endif
+             ],
+             [gl_cv_func_strcasestr_works_always="guessing yes"],
+             [gl_cv_func_strcasestr_works_always="guessing no"])
+          ])
+        ])
+      case "$gl_cv_func_strcasestr_works_always" in
+        *yes) ;;
+        *)
+          REPLACE_STRCASESTR=1
+          ;;
+      esac
+    fi
+  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 $REPLACE_STRCASESTR = 0; then
+    AC_CACHE_CHECK([whether strcasestr works in linear time],
+      [gl_cv_func_strcasestr_linear],
+      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <signal.h> /* for signal */
+#include <string.h> /* for strcasestr */
+#include <stdlib.h> /* for malloc */
+#include <unistd.h> /* for alarm */
+static void quit (int sig) { exit (sig + 128); }
+]], [[
+    int result = 0;
+    size_t m = 1000000;
+    char *haystack = (char *) malloc (2 * m + 2);
+    char *needle = (char *) malloc (m + 2);
+    /* Failure to compile this test due to missing alarm is okay,
+       since all such platforms (mingw) also lack strcasestr.  */
+    signal (SIGALRM, quit);
+    alarm (5);
+    /* Check for quadratic performance.  */
+    if (haystack && needle)
+      {
+        memset (haystack, 'A', 2 * m);
+        haystack[2 * m] = 'B';
+        haystack[2 * m + 1] = 0;
+        memset (needle, 'A', m);
+        needle[m] = 'B';
+        needle[m + 1] = 0;
+        if (!strcasestr (haystack, needle))
+          result |= 1;
+      }
+    return result;
+    ]])],
+        [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
+        [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
+         dnl strcasestr that works in linear time.
+         AC_EGREP_CPP([Lucky user],
+           [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
+     && !defined __UCLIBC__
+  Lucky user
+ #endif
+#endif
+#ifdef __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
+  Lucky user
+ #endif
+#endif
+           ],
+           [gl_cv_func_strcasestr_linear="guessing yes"],
+           [gl_cv_func_strcasestr_linear="guessing no"])
+        ])
+      ])
+    case "$gl_cv_func_strcasestr_linear" in
+      *yes) ;;
+      *)
+        REPLACE_STRCASESTR=1
+        ;;
+    esac
+  fi
+]) # gl_FUNC_STRCASESTR
 
 # Prerequisites of lib/strcasestr.c.
 AC_DEFUN([gl_PREREQ_STRCASESTR], [
-  AC_REQUIRE([gl_FUNC_MBRTOWC])
   :
 ])