2006-02-08 Paolo Carlini <pcarlini@suse.de>

	PR libstdc++/26133  (DR 241, [WP])
	* include/bits/stl_algo.h (__unique_copy(,,, forward_iterator_tag,
	output_iterator_tag), __unique_copy(,,, input_iterator_tag,
	output_iterator_tag), __unique_copy(,,, input_iterator_tag,
	forward_iterator_tag), and predicated counterparts): Add.
	(__unique_copy(,,, output_iterator_tag), __unique_copy(,,,
	forward_iterator_tag), and predicated counterparts): Remove.
	(unique_copy): Adjust, dispatch to the three helpers above.
	* testsuite/25_algorithms/unique_copy/2.cc: New.
	* testsuite/25_algorithms/unique_copy/26133.cc: Likewise.
	* testsuite/25_algorithms/unique_copy/3.cc: Likewise.	
	* docs/html/ext/howto.html: Add an entry for DR 241.

	* testsuite/25_algorithms/unique_copy/1.cc: Minor cosmetic changes.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@110772 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 380 insertions, 54 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 9341fd1b51a..84e399303c8 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,20 @@
+2006-02-08  Paolo Carlini  <pcarlini@suse.de>
+
+	PR libstdc++/26133  (DR 241, [WP])
+	* include/bits/stl_algo.h (__unique_copy(,,, forward_iterator_tag,
+	output_iterator_tag), __unique_copy(,,, input_iterator_tag,
+	output_iterator_tag), __unique_copy(,,, input_iterator_tag,
+	forward_iterator_tag), and predicated counterparts): Add.
+	(__unique_copy(,,, output_iterator_tag), __unique_copy(,,,
+	forward_iterator_tag), and predicated counterparts): Remove.
+	(unique_copy): Adjust, dispatch to the three helpers above.
+	* testsuite/25_algorithms/unique_copy/2.cc: New.
+	* testsuite/25_algorithms/unique_copy/26133.cc: Likewise.
+	* testsuite/25_algorithms/unique_copy/3.cc: Likewise.	
+	* docs/html/ext/howto.html: Add an entry for DR 241.
+
+	* testsuite/25_algorithms/unique_copy/1.cc: Minor cosmetic changes.
+
 2006-02-07  Jakub Jelinek  <jakub@redhat.com>
 	    Benjamin Kosnik  <bkoz@redhat.com>
 
diff --git a/libstdc++-v3/docs/html/ext/howto.html b/libstdc++-v3/docs/html/ext/howto.html
index bc0b358b9f3..6aaf994ae50 100644
--- a/libstdc++-v3/docs/html/ext/howto.html
+++ b/libstdc++-v3/docs/html/ext/howto.html
@@ -413,6 +413,13 @@
         However, no specification is given what this constructor should do.
     </dd>
 
+    <dt><a href="lwg-defects.html#241">241</a>:
+        <em>Does unique_copy() require CopyConstructible and Assignable?</em>
+    </dt>
+    <dd>Add an helper for forward_iterator/output_iterator, fix the existing
+        one for input_iterator/output_iterator not to rely on Assignability.
+    </dd>
+
     <dt><a href="lwg-defects.html#243">243</a>:
         <em>get and getline when sentry reports failure</em>
     </dt>
diff --git a/libstdc++-v3/include/bits/stl_algo.h b/libstdc++-v3/include/bits/stl_algo.h
index 355d859a901..d5c8f9ddde6 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -1,6 +1,7 @@
 // Algorithm implementation -*- C++ -*-
 
-// Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
+// 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
@@ -1294,23 +1295,23 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  @if maint
    *  This is an uglified unique_copy(_InputIterator, _InputIterator,
    *                                  _OutputIterator)
-   *  overloaded for output iterators.
+   *  overloaded for forward iterators and output iterator as result.
    *  @endif
   */
-  template<typename _InputIterator, typename _OutputIterator>
+  template<typename _ForwardIterator, typename _OutputIterator>
     _OutputIterator
-    __unique_copy(_InputIterator __first, _InputIterator __last,
+    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
 		  _OutputIterator __result,
-		  output_iterator_tag)
+		  forward_iterator_tag, output_iterator_tag)
     {
       // concept requirements -- taken care of in dispatching function
-      typename iterator_traits<_InputIterator>::value_type __value = *__first;
-      *__result = __value;
-      while (++__first != __last)
-	if (!(__value == *__first))
+      _ForwardIterator __next = __first;
+      *__result = *__first;
+      while (++__next != __last)
+	if (!(*__first == *__next))
 	  {
-	    __value = *__first;
-	    *++__result = __value;
+	    __first = __next;
+	    *++__result = *__first;
 	  }
       return ++__result;
     }
@@ -1319,14 +1320,43 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  @if maint
    *  This is an uglified unique_copy(_InputIterator, _InputIterator,
    *                                  _OutputIterator)
-   *  overloaded for forward iterators.
+   *  overloaded for input iterators and output iterator as result.
+   *  @endif
+  */
+  template<typename _InputIterator, typename _OutputIterator>
+    _OutputIterator
+    __unique_copy(_InputIterator __first, _InputIterator __last,
+		  _OutputIterator __result,
+		  input_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- taken care of in dispatching function
+      *__result = *__first;
+      while (true)
+	{
+	  typename
+	    iterator_traits<_InputIterator>::value_type __value = *__first;
+
+	  if (++__first == __last)
+	    break;
+	  
+	  if (!(__value == *__first))
+	    *++__result = *__first;
+	}
+      return ++__result;
+    }
+
+  /**
+   *  @if maint
+   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
+   *                                  _OutputIterator)
+   *  overloaded for input iterators and forward iterator as result.
    *  @endif
   */
   template<typename _InputIterator, typename _ForwardIterator>
     _ForwardIterator
     __unique_copy(_InputIterator __first, _InputIterator __last,
 		  _ForwardIterator __result,
-		  forward_iterator_tag)
+		  input_iterator_tag, forward_iterator_tag)
     {
       // concept requirements -- taken care of in dispatching function
       *__result = *__first;
@@ -1341,30 +1371,64 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  This is an uglified
    *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
    *              _BinaryPredicate)
-   *  overloaded for output iterators.
+   *  overloaded for forward iterators and output iterator as result.
+   *  @endif
+  */
+  template<typename _ForwardIterator, typename _OutputIterator,
+	   typename _BinaryPredicate>
+    _OutputIterator
+    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
+		  _OutputIterator __result, _BinaryPredicate __binary_pred,
+		  forward_iterator_tag, output_iterator_tag)
+    {
+      // concept requirements -- iterators already checked
+      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
+	  typename iterator_traits<_ForwardIterator>::value_type,
+	  typename iterator_traits<_ForwardIterator>::value_type>)
+
+      _ForwardIterator __next = __first;
+      *__result = *__first;
+      while (++__next != __last)
+	if (!__binary_pred(*__first, *__next))
+	  {
+	    __first = __next;
+	    *++__result = *__first;
+	  }
+      return ++__result;
+    }
+
+  /**
+   *  @if maint
+   *  This is an uglified
+   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
+   *              _BinaryPredicate)
+   *  overloaded for input iterators and output iterator as result.
    *  @endif
   */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryPredicate>
     _OutputIterator
     __unique_copy(_InputIterator __first, _InputIterator __last,
-		  _OutputIterator __result,
-		  _BinaryPredicate __binary_pred,
-		  output_iterator_tag)
+		  _OutputIterator __result, _BinaryPredicate __binary_pred,
+		  input_iterator_tag, output_iterator_tag)
     {
       // concept requirements -- iterators already checked
       __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
 	  typename iterator_traits<_InputIterator>::value_type,
 	  typename iterator_traits<_InputIterator>::value_type>)
 
-      typename iterator_traits<_InputIterator>::value_type __value = *__first;
-      *__result = __value;
-      while (++__first != __last)
-	if (!__binary_pred(__value, *__first))
-	  {
-	    __value = *__first;
-	    *++__result = __value;
-	  }
+      *__result = *__first;
+      while (true)
+	{
+	  typename
+	    iterator_traits<_InputIterator>::value_type __value = *__first;
+
+	  if (++__first == __last)
+	    break;
+	  
+	  if (!__binary_pred(__value, *__first))
+	    *++__result = *__first;
+	}
       return ++__result;
     }
 
@@ -1373,25 +1437,25 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  This is an uglified
    *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
    *              _BinaryPredicate)
-   *  overloaded for forward iterators.
+   *  overloaded for input iterators and forward iterator as result.
    *  @endif
   */
   template<typename _InputIterator, typename _ForwardIterator,
 	   typename _BinaryPredicate>
     _ForwardIterator
     __unique_copy(_InputIterator __first, _InputIterator __last,
-		  _ForwardIterator __result,
-		  _BinaryPredicate __binary_pred,
-		  forward_iterator_tag)
+		  _ForwardIterator __result, _BinaryPredicate __binary_pred,
+		  input_iterator_tag, forward_iterator_tag)
     {
       // concept requirements -- iterators already checked
       __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
-	    typename iterator_traits<_ForwardIterator>::value_type,
-	    typename iterator_traits<_InputIterator>::value_type>)
+	  typename iterator_traits<_ForwardIterator>::value_type,
+	  typename iterator_traits<_InputIterator>::value_type>)
 
       *__result = *__first;
       while (++__first != __last)
-	if (!__binary_pred(*__result, *__first)) *++__result = *__first;
+	if (!__binary_pred(*__result, *__first))
+	  *++__result = *__first;
       return ++__result;
     }
 
@@ -1407,6 +1471,11 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  from groups of consecutive elements that compare equal.
    *  unique_copy() is stable, so the relative order of elements that are
    *  copied is unchanged.
+   *
+   *  @if maint
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
+   *  @endif
   */
   template<typename _InputIterator, typename _OutputIterator>
     inline _OutputIterator
@@ -1421,11 +1490,11 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
 	    typename iterator_traits<_InputIterator>::value_type>)
       __glibcxx_requires_valid_range(__first, __last);
 
-      typedef typename iterator_traits<_OutputIterator>::iterator_category
-	_IterType;
-
-      if (__first == __last) return __result;
-      return std::__unique_copy(__first, __last, __result, _IterType());
+      if (__first == __last)
+	return __result;
+      return std::__unique_copy(__first, __last, __result,
+				std::__iterator_category(__first),
+				std::__iterator_category(__result));
     }
 
   /**
@@ -1442,6 +1511,11 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
    *  true.
    *  unique_copy() is stable, so the relative order of elements that are
    *  copied is unchanged.
+   *
+   *  @if maint
+   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
+   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
+   *  @endif
   */
   template<typename _InputIterator, typename _OutputIterator,
 	   typename _BinaryPredicate>
@@ -1456,12 +1530,11 @@ _GLIBCXX_BEGIN_NAMESPACE(std)
 	    typename iterator_traits<_InputIterator>::value_type>)
       __glibcxx_requires_valid_range(__first, __last);
 
-      typedef typename iterator_traits<_OutputIterator>::iterator_category
-	_IterType;
-
-      if (__first == __last) return __result;
-      return std::__unique_copy(__first, __last, __result,
-				__binary_pred, _IterType());
+      if (__first == __last)
+	return __result;
+      return std::__unique_copy(__first, __last, __result, __binary_pred,
+				std::__iterator_category(__first),
+				std::__iterator_category(__result));
     }
 
   /**
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique_copy/1.cc b/libstdc++-v3/testsuite/25_algorithms/unique_copy/1.cc
index 29c4e26c478..06a38f8fee1 100644
--- a/libstdc++-v3/testsuite/25_algorithms/unique_copy/1.cc
+++ b/libstdc++-v3/testsuite/25_algorithms/unique_copy/1.cc
@@ -1,4 +1,4 @@
-// Copyright (C) 2005 Free Software Foundation, Inc.
+// Copyright (C) 2005, 2006 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
@@ -16,7 +16,7 @@
 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 // USA.
 
-// 25.5.8 [lib.alg.unique]
+// 25.2.8 [lib.alg.unique]
 
 #include <algorithm>
 #include <testsuite_hooks.h>
@@ -26,7 +26,7 @@ using __gnu_test::test_container;
 using __gnu_test::input_iterator_wrapper;
 using __gnu_test::forward_iterator_wrapper;
 using __gnu_test::output_iterator_wrapper;
-using std::unique;
+using std::unique_copy;
 
 typedef test_container<int, input_iterator_wrapper> Icontainer;
 typedef test_container<int, forward_iterator_wrapper> Fcontainer;
@@ -41,7 +41,7 @@ test1()
   bool test __attribute__((unused)) = true;
   Icontainer con1(array1, array1);
   Ocontainer con2(array2, array2);
-  VERIFY(unique_copy(con1.begin(), con1.end(), con2.begin()).ptr == array2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr == array2 );
 }
 
 void
@@ -50,9 +50,9 @@ test2()
   bool test __attribute__((unused)) = true;
   Icontainer con1(array1, array1 + 6);
   Ocontainer con2(array2, array2 + 2);
-  VERIFY(unique_copy(con1.begin(), con1.end(), con2.begin()).ptr 
-         == array2 + 2);
-  VERIFY(array2[0] == 0 && array2[1] == 1);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr 
+	  == array2 + 2 );
+  VERIFY( array2[0] == 0 && array2[1] == 1 );
 }
 
 void
@@ -61,7 +61,7 @@ test3()
   bool test __attribute__((unused)) = true;
   Icontainer con1(array1, array1);
   Fcontainer con2(array2, array2);
-  VERIFY(unique_copy(con1.begin(), con1.end(), con2.begin()).ptr == array2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr == array2 );
 }
 
 void
@@ -70,9 +70,9 @@ test4()
   bool test __attribute__((unused)) = true;
   Icontainer con1(array1, array1 + 6);
   Fcontainer con2(array2, array2 + 2);
-  VERIFY(unique_copy(con1.begin(), con1.end(), con2.begin()).ptr
-         == array2 + 2);
-  VERIFY(array2[0] == 0 && array2[1] == 1);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr
+	  == array2 + 2 );
+  VERIFY( array2[0] == 0 && array2[1] == 1 );
 }
 
 int 
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique_copy/2.cc b/libstdc++-v3/testsuite/25_algorithms/unique_copy/2.cc
new file mode 100644
index 00000000000..13500916542
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/unique_copy/2.cc
@@ -0,0 +1,85 @@
+// Copyright (C) 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+// 25.2.8 [lib.alg.unique]
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+using __gnu_test::test_container;
+using __gnu_test::forward_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+using std::unique_copy;
+using std::equal_to;
+
+typedef test_container<int, forward_iterator_wrapper> Fcontainer;
+typedef test_container<int, output_iterator_wrapper> Ocontainer;
+
+int array1[] = {0, 0, 0, 1, 1, 1};
+int array2[2];
+
+void
+test1()
+{
+  bool test __attribute__((unused)) = true;
+  Fcontainer con1(array1, array1);
+  Ocontainer con2(array2, array2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr == array2 );
+}
+
+void
+test2()
+{
+  bool test __attribute__((unused)) = true;
+  Fcontainer con1(array1, array1 + 6);
+  Ocontainer con2(array2, array2 + 2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr
+	  == array2 + 2 );
+  VERIFY( array2[0] == 0 && array2[1] == 1 );
+}
+
+void
+test3()
+{
+  bool test __attribute__((unused)) = true;
+  Fcontainer con1(array1, array1);
+  Ocontainer con2(array2, array2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin(),
+		      equal_to<int>()).ptr == array2 );
+}
+
+void
+test4()
+{
+  bool test __attribute__((unused)) = true;
+  Fcontainer con1(array1, array1 + 6);
+  Ocontainer con2(array2, array2 + 2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin(),
+		      equal_to<int>()).ptr == array2 + 2 );
+  VERIFY( array2[0] == 0 && array2[1] == 1 );
+}
+
+int 
+main()
+{
+  test1();
+  test2();
+  test3();
+  test4();
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique_copy/26133.cc b/libstdc++-v3/testsuite/25_algorithms/unique_copy/26133.cc
new file mode 100644
index 00000000000..2c77667a12c
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/unique_copy/26133.cc
@@ -0,0 +1,51 @@
+// Copyright (C) 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+#include <algorithm>
+#include <iterator>
+#include <sstream>
+#include <testsuite_hooks.h>
+
+struct no_assign
+{
+  int const x;
+  no_assign() : x(23) { }
+  operator int() const { return x; }
+};
+
+// libstdc++/26133
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+  std::ostringstream oss1, oss2;
+
+  no_assign in[4];
+
+  std::unique_copy(in, in + 4, std::ostream_iterator<int>(oss1, "\n"));
+  VERIFY( oss1.str() == "23\n" );
+
+  std::unique_copy(in, in + 4, std::ostream_iterator<int>(oss2, "\n"),
+		   std::equal_to<int>());
+  VERIFY( oss2.str() == "23\n" );
+}
+
+int main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/unique_copy/3.cc b/libstdc++-v3/testsuite/25_algorithms/unique_copy/3.cc
new file mode 100644
index 00000000000..2245821f7c1
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/unique_copy/3.cc
@@ -0,0 +1,93 @@
+// Copyright (C) 2006 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+// USA.
+
+// 25.2.8 [lib.alg.unique]
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+using __gnu_test::test_container;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+using std::unique_copy;
+using std::equal_to;
+
+struct no_assign
+{
+  int const x;
+  no_assign() : x(23) { }
+  no_assign(int val) : x(val) { }
+  operator int() const { return x; }
+};
+
+typedef test_container<no_assign, input_iterator_wrapper> Icontainer;
+typedef test_container<int, output_iterator_wrapper> Ocontainer;
+
+no_assign array1[] = {0, 0, 0, 1, 1, 1};
+int array2[2];
+
+void
+test1()
+{
+  bool test __attribute__((unused)) = true;
+  Icontainer con1(array1, array1);
+  Ocontainer con2(array2, array2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr == array2 );
+}
+
+void
+test2()
+{
+  bool test __attribute__((unused)) = true;
+  Icontainer con1(array1, array1 + 6);
+  Ocontainer con2(array2, array2 + 2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin()).ptr
+	  == array2 + 2 );
+  VERIFY( array2[0] == 0 && array2[1] == 1 );
+}
+
+void
+test3()
+{
+  bool test __attribute__((unused)) = true;
+  Icontainer con1(array1, array1);
+  Ocontainer con2(array2, array2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin(),
+		      equal_to<int>()).ptr == array2 );
+}
+
+void
+test4()
+{
+  bool test __attribute__((unused)) = true;
+  Icontainer con1(array1, array1 + 6);
+  Ocontainer con2(array2, array2 + 2);
+  VERIFY( unique_copy(con1.begin(), con1.end(), con2.begin(),
+		      equal_to<int>()).ptr == array2 + 2 );
+  VERIFY( array2[0] == 0 && array2[1] == 1 );
+}
+
+int 
+main()
+{
+  test1();
+  test2();
+  test3();
+  test4();
+}