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/*
* Copyright 2002, The libsigc++ Development Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#ifndef _SIGC_REFERENCE_WRAPPER_H_
#define _SIGC_REFERENCE_WRAPPER_H_
namespace sigc {
/** Reference wrapper.
* Use sigc::ref() to create a reference wrapper.
*/
template <class T_type>
struct reference_wrapper
{
explicit reference_wrapper(T_type& v)
: value_(v) {}
operator T_type& () const
{ return value_; }
T_type& value_;
};
/** Const reference wrapper.
* Use sigc::ref() to create a const reference wrapper.
*/
template <class T_type>
struct const_reference_wrapper
{
explicit const_reference_wrapper(const T_type& v)
: value_(v) {}
operator const T_type& () const
{ return value_; }
const T_type& value_;
};
/** Creates a reference wrapper.
* Passing an object throught sigc::ref() makes libsigc++ adaptors
* like, e.g., sigc::bind store references to the object instead of copies.
* If the object type inherits from sigc::trackable this will ensure
* automatic invalidation of the adaptors when the object is deleted
* or overwritten.
*
* @param v Reference to store.
* @return A reference wrapper.
*/
template <class T_type>
reference_wrapper<T_type> ref(T_type& v)
{ return reference_wrapper<T_type>(v); }
/** Creates a const reference wrapper.
* Passing an object throught sigc::ref() makes libsigc++ adaptors
* like, e.g., sigc::bind store references to the object instead of copies.
* If the object type inherits from sigc::trackable this will ensure
* automatic invalidation of the adaptors when the object is deleted
* or overwritten.
*
* @param v Reference to store.
* @return A reference wrapper.
*/
template <class T_type>
const_reference_wrapper<T_type> ref(const T_type& v)
{ return const_reference_wrapper<T_type>(v); }
template <class T_type>
struct unwrap_reference
{
typedef T_type type;
};
template <class T_type>
struct unwrap_reference<reference_wrapper<T_type> >
{
typedef T_type& type;
};
template <class T_type>
struct unwrap_reference<const_reference_wrapper<T_type> >
{
typedef const T_type& type;
};
template <class T_type>
T_type& unwrap(T_type& v)
{ return v; }
template <class T_type>
const T_type& unwrap(const T_type& v)
{ return v; }
template <class T_type>
T_type& unwrap(const reference_wrapper<T_type>& v)
{ return v; }
template <class T_type>
const T_type& unwrap(const const_reference_wrapper<T_type>& v)
{ return v; }
} /* namespace sigc */
#endif /* _SIGC_REFERENCE_WRAPPER_H_ */
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