119 lines
3.1 KiB
C++
119 lines
3.1 KiB
C++
/*
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* Copyright 2002, The libsigc++ Development Team
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#ifndef _SIGC_REFERENCE_WRAPPER_H_
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#define _SIGC_REFERENCE_WRAPPER_H_
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namespace sigc {
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/** Reference wrapper.
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* Use sigc::ref() to create a reference wrapper.
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*/
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template <class T_type>
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struct reference_wrapper
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{
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explicit reference_wrapper(T_type& v)
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: value_(v) {}
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operator T_type& () const
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{ return value_; }
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T_type& value_;
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};
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/** Const reference wrapper.
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* Use sigc::ref() to create a const reference wrapper.
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*/
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template <class T_type>
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struct const_reference_wrapper
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{
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explicit const_reference_wrapper(const T_type& v)
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: value_(v) {}
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operator const T_type& () const
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{ return value_; }
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const T_type& value_;
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};
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/** Creates a reference wrapper.
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* Passing an object throught sigc::ref() makes libsigc++ adaptors
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* like, e.g., sigc::bind store references to the object instead of copies.
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* If the object type inherits from sigc::trackable this will ensure
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* automatic invalidation of the adaptors when the object is deleted
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* or overwritten.
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*
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* @param v Reference to store.
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* @return A reference wrapper.
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*/
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template <class T_type>
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reference_wrapper<T_type> ref(T_type& v)
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{ return reference_wrapper<T_type>(v); }
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/** Creates a const reference wrapper.
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* Passing an object throught sigc::ref() makes libsigc++ adaptors
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* like, e.g., sigc::bind store references to the object instead of copies.
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* If the object type inherits from sigc::trackable this will ensure
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* automatic invalidation of the adaptors when the object is deleted
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* or overwritten.
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*
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* @param v Reference to store.
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* @return A reference wrapper.
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*/
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template <class T_type>
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const_reference_wrapper<T_type> ref(const T_type& v)
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{ return const_reference_wrapper<T_type>(v); }
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template <class T_type>
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struct unwrap_reference
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{
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typedef T_type type;
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};
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template <class T_type>
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struct unwrap_reference<reference_wrapper<T_type> >
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{
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typedef T_type& type;
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};
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template <class T_type>
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struct unwrap_reference<const_reference_wrapper<T_type> >
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{
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typedef const T_type& type;
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};
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template <class T_type>
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T_type& unwrap(T_type& v)
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{ return v; }
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template <class T_type>
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const T_type& unwrap(const T_type& v)
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{ return v; }
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template <class T_type>
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T_type& unwrap(const reference_wrapper<T_type>& v)
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{ return v; }
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template <class T_type>
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const T_type& unwrap(const const_reference_wrapper<T_type>& v)
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{ return v; }
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} /* namespace sigc */
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#endif /* _SIGC_REFERENCE_WRAPPER_H_ */
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