forward_list.h (forward_list::assign): Dispatch to new functions based on assignability of elements.

	* include/bits/forward_list.h (forward_list::assign): Dispatch to new
	functions based on assignability of elements.
	(forward_list::_M_assign): Add overloaded functions for assigning
	via assignment or via clearing and insertion.
	(forward_list::_M_assign_val): Likewise.
	(forward_list::_M_move_assign(forward_list&&, false_type)): Do not
	erase elements that are not moved.
	* include/bits/forward_list.tcc (forward_list::operator=): Call
	assign() to copy elements.
	* testsuite/23_containers/forward_list/cons/10.cc: New.
	* testsuite/23_containers/forward_list/cons/11.cc: New.
	* testsuite/23_containers/forward_list/cons/12.cc: New.

From-SVN: r193057

6 files changed, 255 insertions, 35 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 444efda..611570d 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,18 @@
+2012-11-01  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
+	* include/bits/forward_list.h (forward_list::assign): Dispatch to new
+	functions based on assignability of elements.
+	(forward_list::_M_assign): Add overloaded functions for assigning
+	via assignment or via clearing and insertion.
+	(forward_list::_M_assign_val): Likewise.
+	(forward_list::_M_move_assign(forward_list&&, false_type)): Do not
+	erase elements that are not moved.
+	* include/bits/forward_list.tcc (forward_list::operator=): Call
+	assign() to copy elements.
+	* testsuite/23_containers/forward_list/cons/10.cc: New.
+	* testsuite/23_containers/forward_list/cons/11.cc: New.
+	* testsuite/23_containers/forward_list/cons/12.cc: New.
+
 2012-10-31  Jonathan Yong  <jon_y@users.sourceforge.net>
 
 	* config/os/mingw32-w64/os_defines.h: Do not define anymore
diff --git a/libstdc++-v3/include/bits/forward_list.h b/libstdc++-v3/include/bits/forward_list.h
index 8d4915d..b40fe9b 100644
--- a/libstdc++-v3/include/bits/forward_list.h
+++ b/libstdc++-v3/include/bits/forward_list.h
@@ -589,7 +589,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
        *  in the range [@a __first,@a __last).
        *
        *  Note that the assignment completely changes the %forward_list and
-       *  that the number of elements of the resulting %forward_list's is the
+       *  that the number of elements of the resulting %forward_list is the
        *  same as the number of elements assigned.  Old data is lost.
        */
       template<typename _InputIterator,
@@ -597,9 +597,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 	void
         assign(_InputIterator __first, _InputIterator __last)
         {
-          clear();
-          insert_after(cbefore_begin(), __first, __last);
-        }
+	  typedef is_assignable<_Tp, decltype(*__first)> __assignable;
+	  _M_assign(__first, __last, __assignable());
+	}
 
       /**
        *  @brief  Assigns a given value to a %forward_list.
@@ -613,10 +613,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
        */
       void
       assign(size_type __n, const _Tp& __val)
-      {
-        clear();
-        insert_after(cbefore_begin(), __n, __val);
-      }
+      { _M_assign_n(__n, __val, is_copy_assignable<_Tp>()); }
 
       /**
        *  @brief  Assigns an initializer_list to a %forward_list.
@@ -628,10 +625,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
        */
       void
       assign(std::initializer_list<_Tp> __il)
-      {
-        clear();
-        insert_after(cbefore_begin(), __il);
-      }
+      { assign(__il.begin(), __il.end()); }
 
       /// Get a copy of the memory allocation object.
       allocator_type
@@ -1255,13 +1249,70 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
         if (__list._M_get_Node_allocator() == this->_M_get_Node_allocator())
           _M_move_assign(std::move(__list), std::true_type());
         else
-          {
-            // The rvalue's allocator cannot be moved, or is not equal,
-            // so we need to individually move each element.
-            this->assign(std::__make_move_if_noexcept_iterator(__list.begin()),
-                         std::__make_move_if_noexcept_iterator(__list.end()));
-            __list.clear();
-          }
+	  // The rvalue's allocator cannot be moved, or is not equal,
+	  // so we need to individually move each element.
+	  this->assign(std::__make_move_if_noexcept_iterator(__list.begin()),
+		       std::__make_move_if_noexcept_iterator(__list.end()));
+      }
+
+      // Called by assign(_InputIterator, _InputIterator) if _Tp is
+      // CopyAssignable.
+      template<typename _InputIterator>
+	void
+        _M_assign(_InputIterator __first, _InputIterator __last, true_type)
+	{
+	  auto __prev = before_begin();
+	  auto __curr = begin();
+	  auto __end = end();
+	  while (__curr != __end && __first != __last)
+	    {
+	      *__curr = *__first;
+	      ++__prev;
+	      ++__curr;
+	      ++__first;
+	    }
+	  if (__first != __last)
+	    insert_after(__prev, __first, __last);
+	  else if (__curr != __end)
+	    erase_after(__prev, __end);
+        }
+
+      // Called by assign(_InputIterator, _InputIterator) if _Tp is not
+      // CopyAssignable.
+      template<typename _InputIterator>
+	void
+        _M_assign(_InputIterator __first, _InputIterator __last, false_type)
+	{
+	  clear();
+	  insert_after(cbefore_begin(), __first, __last);
+	}
+
+      // Called by assign(size_type, const _Tp&) if Tp is CopyAssignable
+      void
+      _M_assign_n(size_type __n, const _Tp& __val, true_type)
+      {
+	auto __prev = before_begin();
+	auto __curr = begin();
+	auto __end = end();
+	while (__curr != __end && __n > 0)
+	  {
+	    *__curr = __val;
+	    ++__prev;
+	    ++__curr;
+	    --__n;
+	  }
+	if (__n > 0)
+	  insert_after(__prev, __n, __val);
+	else if (__curr != __end)
+	  erase_after(__prev, __end);
+      }
+
+      // Called by assign(size_type, const _Tp&) if Tp is non-CopyAssignable
+      void
+      _M_assign_n(size_type __n, const _Tp& __val, false_type)
+      {
+	clear();
+	insert_after(cbefore_begin(), __n, __val);
       }
     };
 
diff --git a/libstdc++-v3/include/bits/forward_list.tcc b/libstdc++-v3/include/bits/forward_list.tcc
index 4f9a7fa..7395b20 100644
--- a/libstdc++-v3/include/bits/forward_list.tcc
+++ b/libstdc++-v3/include/bits/forward_list.tcc
@@ -165,22 +165,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 		}
 	      std::__alloc_on_copy(__this_alloc, __that_alloc);
             }
-          iterator __prev1 = before_begin();
-          iterator __curr1 = begin();
-          iterator __last1 = end();
-          const_iterator __first2 = __list.cbegin();
-          const_iterator __last2 = __list.cend();
-          while (__curr1 != __last1 && __first2 != __last2)
-            {
-              *__curr1 = *__first2;
-              ++__prev1;
-              ++__curr1;
-              ++__first2;
-            }
-          if (__first2 == __last2)
-            erase_after(__prev1, __last1);
-          else
-            insert_after(__prev1, __first2, __last2);
+	  assign(__list.cbegin(), __list.cend());
         }
       return *this;
     }
diff --git a/libstdc++-v3/testsuite/23_containers/forward_list/cons/10.cc b/libstdc++-v3/testsuite/23_containers/forward_list/cons/10.cc
new file mode 100644
index 0000000..8c64ed4
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/forward_list/cons/10.cc
@@ -0,0 +1,58 @@
+// { dg-options "-std=gnu++11" }
+
+// Copyright (C) 2012 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 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without Pred 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 COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// 23.3.4.2 forward_list construction [forwardlist.cons]
+
+#include <forward_list>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+struct Counter
+{
+  Counter() { ++create; }
+  Counter(const Counter&) { ++create; }
+  ~Counter() { ++destroy; }
+
+  static int create;
+  static int destroy;
+};
+
+int Counter::create = 0;
+int Counter::destroy = 0;
+
+void test01()
+{
+  typedef __gnu_test::uneq_allocator<Counter> alloc;
+  typedef std::forward_list<Counter, alloc> list;
+
+  {
+    Counter c;
+
+    list l( list(10, c, alloc(1)), alloc(2) );
+
+    VERIFY( Counter::create == 21 );
+    VERIFY( Counter::destroy == 10 );
+  }
+  VERIFY( Counter::destroy == 21 );
+}
+
+int main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/23_containers/forward_list/cons/11.cc b/libstdc++-v3/testsuite/23_containers/forward_list/cons/11.cc
new file mode 100644
index 0000000..4c99305
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/forward_list/cons/11.cc
@@ -0,0 +1,50 @@
+// { dg-options "-std=gnu++11" }
+
+// Copyright (C) 2012 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 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without Pred 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 COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// 23.3.4.2 forward_list construction [forwardlist.cons]
+
+#include <forward_list>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+bool fail = false;
+
+struct A
+{
+  A() = default;
+  A(const A&) { if (fail) throw fail; }
+};
+
+void test01()
+{
+  typedef std::forward_list<A> list;
+
+  list l(2);
+  A from[2];
+  fail = true;
+  // Check existing elements are assigned to, instead of creating new ones.
+  // This is QoI, not required by the standard.
+  l.assign(from, from+2);
+  l.assign(2, from[0]);
+}
+
+int main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/23_containers/forward_list/cons/12.cc b/libstdc++-v3/testsuite/23_containers/forward_list/cons/12.cc
new file mode 100644
index 0000000..a1fc3c3
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/forward_list/cons/12.cc
@@ -0,0 +1,61 @@
+// { dg-do compile }
+// { dg-options "-std=gnu++11" }
+
+// Copyright (C) 2012 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 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without Pred 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 COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// 23.3.4.2 forward_list construction [forwardlist.cons]
+
+#include <forward_list>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+bool fail = false;
+
+struct NonCopyAssignable
+{
+  NonCopyAssignable() = default;
+  NonCopyAssignable(const NonCopyAssignable&) = default;
+  NonCopyAssignable(int) { }
+
+  NonCopyAssignable& operator=(const NonCopyAssignable&) = delete;
+  NonCopyAssignable& operator=(int) = delete;
+};
+
+void test01()
+{
+  typedef std::forward_list<NonCopyAssignable> list;
+
+  list l(2);
+  NonCopyAssignable from[2];
+  int from2[2];
+
+  // Assigning non-Assignable elements is QoI, not required by the standard.
+
+  l = l;
+
+  l.assign(from, from+2);
+  l.assign(2, from[0]);
+
+  l.assign(from2, from2+2);
+  l.assign(2, from2[0]);
+}
+
+int main()
+{
+  test01();
+}