Author: elemings
Date: Fri Jun 13 13:16:06 2008
New Revision: 667636
URL: http://svn.apache.org/viewvc?rev=667636&view=rev
Log:
2008-06-13 Eric Lemings <[EMAIL PROTECTED]>
STDCXX-958
* include/rw/_forward.h: New header file containing initial
implementation of std::identity class template; std::forward()
and std::move() functions; and internal _RWSTD_MOVE() macro.
Added:
stdcxx/branches/4.3.x/include/rw/_forward.h
Added: stdcxx/branches/4.3.x/include/rw/_forward.h
URL:
http://svn.apache.org/viewvc/stdcxx/branches/4.3.x/include/rw/_forward.h?rev=667636&view=auto
==============================================================================
--- stdcxx/branches/4.3.x/include/rw/_forward.h (added)
+++ stdcxx/branches/4.3.x/include/rw/_forward.h Fri Jun 13 13:16:06 2008
@@ -0,0 +1,126 @@
+// -*- C++ -*-
+/***************************************************************************
+ *
+ * _forward - forward/move helpers for <utility> header
+ *
+ * $Id$
+ *
+ ***************************************************************************
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ *
+ * Copyright 2008 Rogue Wave Software.
+ *
+ **************************************************************************/
+
+#ifndef _RWSTD_RW_FORWARD_INCLUDED
+# define _RWSTD_RW_FORWARD_INCLUDED
+
+# if !defined _RWSTD_NO_EXT_CXX_0X
+
+# include <rw/_defs.h>
+# include <rw/_meta_ref.h> // for __rw_remove_reference
+
+
+_RWSTD_NAMESPACE (std) {
+
+
+// [20.2.2] forward/move helpers
+
+/**
+ * An identity wrapper. Similar to the identity property, the identity
+ * wrapper is a class template that simply reflects the type of its
+ * template parameter. This class template is used when a template
+ * parameter type must be explicitly specified in order to apply the
+ * correct move/forwarding semantics, usually in the \c std::forward()
+ * function.
+ *
+ * @param _Type Any type. No restrictions or requirements.
+ * @see std::forward
+ */
+template <class _Type>
+struct identity
+{
+ /** Identifies template parameter type. */
+ typedef _Type type;
+
+ /**
+ * Conversion operator. This operator converts the parameter value
+ * to the wrapped identity type.
+ *
+ * @param __x An value convertible to identity type.
+ * @returns Same value as the function argument with identity type.
+ */
+ const _Type& operator() (const _Type& __x) {
+ return __x;
+ }
+};
+
+
+# if !defined _RWSTD_NO_RVALUE_REFERENCES
+
+/**
+ * Forwards appropriate rvalue or lvalue reference type. This function
+ * is used to ensure that the appropriate reference type is used in move
+ * semantics.
+ *
+ * @param _Type An lvalue or rvalue reference type.
+ * @param __x An lvalue reference or rvalue reference.
+ * @returns An lvalue if __x is an lvalue reference; otherwise, an rvalue.
+ */
+_EXPORT
+template <class _Type>
+_Type&&
+forward (_TYPENAME identity<_Type>::type&& __x)
+{
+ return __x;
+}
+
+/**
+ * Move a value to an rvalue reference. This function is used to
+ * explicitly bind constructors and other functions with rvalue
+ * references that employ move semantics.
+ *
+ * @param __x An lvalue or rvalue.
+ * @returns Same value as parameter with rvalue reference type.
+ */
+_EXPORT
+template <class _Type>
+_TYPENAME _RW::__rw_remove_reference<_Type>::type&&
+move (_Type&& __x)
+{
+ return __x;
+}
+
+/**
+ * @internal
+ * Internal wrapper macro to utilize move semantics if available.
+ * @param __x An lvalue or rvalue.
+ */
+# define _RWSTD_MOVE(__x) std::move (__x)
+# else // no rvalue references
+# define _RWSTD_MOVE(__x) (__x)
+
+# endif // !defined _RWSTD_NO_RVALUE_REFERENCES
+
+
+} // namespace std
+
+
+# endif // !defined _RWSTD_NO_EXT_CXX_0X
+
+#endif // _RWSTD_RW_FORWARD_INCLUDED
