[v3] Fix libstdc++/19955

[Paolo Carlini <pcarlini at suse dot de>]

Hi,

the below fixes a regression, unfortunately introduced in 3_4
together with performance improvements. Will commit to 4_0 and
3_4 too, after a few days.

Tested for correctness and performance on x86-linux.

Paolo.

////////////////
2005-02-15  Paolo Carlini  <pcarlini@suse.de>
	    Jon Grimm  <jgrimm2@us.ibm.com>
	
	PR libstdc++/19955
	* include/bits/locale_facets.h (ctype<char>::_M_narrow_init()):
	Fix the logic setting _M_narrow_ok: first check whether the
	transformation is trivial with a dflt == 0, then deal with the
	special case of zero.
	* testsuite/22_locale/ctype/narrow/char/19955.cc: New.

	* include/bits/locale_facets.h (ctype<char>::_M_widen_init()):
	Tweak consistently to use memcmp; minor formatting fixes.

diff -urN libstdc++-v3-orig/include/bits/locale_facets.h libstdc++-v3/include/bits/locale_facets.h
--- libstdc++-v3-orig/include/bits/locale_facets.h	2004-11-23 10:18:39.000000000 +0100
+++ libstdc++-v3/include/bits/locale_facets.h	2005-02-15 23:23:27.000000000 +0100
@@ -1,6 +1,6 @@
 // Locale support -*- C++ -*-
 
-// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -690,7 +690,7 @@
       mutable char		_M_widen[1 + static_cast<unsigned char>(-1)];
       mutable char		_M_narrow[1 + static_cast<unsigned char>(-1)];
       mutable char		_M_narrow_ok;	// 0 uninitialized, 1 init,
-						// 2 non-consecutive
+						// 2 memcpy can't be used
 
     public:
       /// The facet id for ctype<char>
@@ -865,7 +865,8 @@
       char_type
       widen(char __c) const
       {
-	if (_M_widen_ok) return _M_widen[static_cast<unsigned char>(__c)];
+	if (_M_widen_ok)
+	  return _M_widen[static_cast<unsigned char>(__c)];
 	this->_M_widen_init();
 	return this->do_widen(__c);
       }
@@ -896,7 +897,8 @@
 	    memcpy(__to, __lo, __hi - __lo);
 	    return __hi;
 	  }
-	if (!_M_widen_ok) _M_widen_init();
+	if (!_M_widen_ok)
+	  _M_widen_init();
 	return this->do_widen(__lo, __hi, __to);
       }
 
@@ -924,7 +926,8 @@
 	if (_M_narrow[static_cast<unsigned char>(__c)])
 	  return _M_narrow[static_cast<unsigned char>(__c)];
 	const char __t = do_narrow(__c, __dfault);
-	if (__t != __dfault) _M_narrow[static_cast<unsigned char>(__c)] = __t;
+	if (__t != __dfault)
+	  _M_narrow[static_cast<unsigned char>(__c)] = __t;
 	return __t;
       }
 
@@ -954,7 +957,7 @@
       narrow(const char_type* __lo, const char_type* __hi,
 	     char __dfault, char *__to) const
       {
-	if (__builtin_expect(_M_narrow_ok == 1,true))
+	if (__builtin_expect(_M_narrow_ok == 1, true))
 	  {
 	    memcpy(__to, __lo, __hi - __lo);
 	    return __hi;
@@ -1161,17 +1164,13 @@
 
 	_M_widen_ok = 1;
 	// Set _M_widen_ok to 2 if memcpy can't be used.
-	for (size_t __j = 0; __j < sizeof(_M_widen); ++__j)
-	  if (__tmp[__j] != _M_widen[__j])
-	    {
-	      _M_widen_ok = 2;
-	      break;
-	    }
+	if (memcmp(__tmp, _M_widen, sizeof(_M_widen)))
+	  _M_widen_ok = 2;
       }
 
       // Fill in the narrowing cache and flag whether all values are
-      // valid or not.  _M_narrow_ok is set to 1 if the whole table is
-      // narrowed, 2 if only some values could be narrowed.
+      // valid or not.  _M_narrow_ok is set to 2 if memcpy can't
+      // be used.
       void _M_narrow_init() const
       {
 	char __tmp[sizeof(_M_narrow)];
@@ -1179,21 +1178,18 @@
 	  __tmp[__i] = __i;
 	do_narrow(__tmp, __tmp + sizeof(__tmp), 0, _M_narrow);
 
-	// Check if any default values were created.  Do this by
-	// renarrowing with a different default value and comparing.
-	bool __consecutive = true;
-	for (size_t __j = 0; __j < sizeof(_M_narrow); ++__j)
-	  if (!_M_narrow[__j])
-	    {
-	      char __c;
-	      do_narrow(__tmp + __j, __tmp + __j + 1, 1, &__c);
-	      if (__c == 1)
-		{
-		  __consecutive = false;
-		  break;
-		}
-	    }
-	_M_narrow_ok = __consecutive ? 1 : 2;
+	_M_narrow_ok = 1;
+	if (memcmp(__tmp, _M_narrow, sizeof(_M_narrow)))
+	  _M_narrow_ok = 2;
+	else
+	  {
+	    // Deal with the special case of zero: renarrow with a
+	    // different default and compare.
+	    char __c;
+	    do_narrow(__tmp, __tmp + 1, 1, &__c);
+	    if (__c == 1)
+	      _M_narrow_ok = 2;
+	  }
       }
     };
 
diff -urN libstdc++-v3-orig/testsuite/22_locale/ctype/narrow/char/19955.cc libstdc++-v3/testsuite/22_locale/ctype/narrow/char/19955.cc
--- libstdc++-v3-orig/testsuite/22_locale/ctype/narrow/char/19955.cc	1970-01-01 01:00:00.000000000 +0100
+++ libstdc++-v3/testsuite/22_locale/ctype/narrow/char/19955.cc	2005-02-15 23:34:00.000000000 +0100
@@ -0,0 +1,105 @@
+// Copyright (C) 2005 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library 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.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// 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 library; see the file COPYING.  If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction.  Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License.  This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+// 22.2.1.3.2 ctype<char> members
+
+#include <locale>
+#include <testsuite_hooks.h>
+
+class Ctype1
+: public std::ctype<char> 
+{
+protected:
+  const char*
+  do_narrow(const char* lo, const char* hi,
+	    char dflt, char* to) const 
+  {
+    for (int i = 0; lo != hi; ++lo, ++to, ++i)
+      *to = *lo + i;
+    return hi;
+  }
+};
+
+class Ctype2
+: public std::ctype<char> 
+{
+protected:
+  const char*
+  do_narrow(const char* lo, const char* hi,
+	    char dflt, char* to) const 
+  {
+    for (int i = 0; lo != hi; ++lo, ++to, ++i)
+      if (*lo == '\000')
+	*to = dflt;
+      else
+	*to = *lo;
+    return hi;
+  }
+};
+
+// libstdc++/19955
+void test01() 
+{
+  using namespace std;
+  bool test __attribute__((unused)) = true;
+
+  const char src[] = "abcd";
+
+  locale mylocale1(locale::classic(), new Ctype1);
+  const ctype<char>& mc1 = use_facet<ctype<char> >(mylocale1);
+
+  char dst1[sizeof(src)];
+  memset(dst1, 0, sizeof(src));
+  char dst2[sizeof(src)];
+  memset(dst2, 0, sizeof(src));
+  
+  mc1.narrow(src, src + sizeof(src), '*', dst1);
+  mc1.narrow(src, src + sizeof(src), '*', dst2);
+
+  VERIFY( !memcmp(dst1, "aceg\004", 5) );
+  VERIFY( !memcmp(dst1, dst2, 5) );
+
+  locale mylocale2(locale::classic(), new Ctype2);
+  const ctype<char>& mc2 = use_facet<ctype<char> >(mylocale2);
+
+  char dst3[sizeof(src)];
+  memset(dst3, 0, sizeof(src));
+  char dst4[sizeof(src)];
+  memset(dst4, 0, sizeof(src));
+  
+  mc2.narrow(src, src + sizeof(src), '*', dst3);
+  mc2.narrow(src, src + sizeof(src), '*', dst4);
+
+  VERIFY( !memcmp(dst3, "abcd*", 5) );
+  VERIFY( !memcmp(dst3, dst4, 5) );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}