LUMIERA.clone/src/lib/iter-type-binding.hpp

84 lines
2.5 KiB
C++

/*
ITER-TYPE-BINDING.hpp - control type variations for IterAdapter
Copyright (C) Lumiera.org
2010, Hermann Vosseler <Ichthyostega@web.de>
This program 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 of
the License, or (at your option) any later version.
This program 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 program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file iter-type-binding.hpp
** Type re-binding helper template for IterAdapter and friends.
** This header defines a trait template which is used by the Iterator
** adapters to figure out the value-, pointer- and reference types
** when wrapping iterators or containers. For extending the use of
** Iterator adapters and Iter-tools to situations involving const
** iterators or custom containers, explicit specialisations
** might be injected prior to instantiating the Iterator adapter
** template.
**
** @see iter-adapter.hpp
** @see scope-path.hpp usage example (explicit specialisation)
*/
#ifndef LIB_ITER_TYPE_BINDING_H
#define LIB_ITER_TYPE_BINDING_H
#include "lib/error.hpp"
namespace lib {
namespace iter {
/**
* Type re-binding helper template for creating nested typedefs
* for use by IterAdapter or similar "Lumiera Forward Iterators".
* This trait provides a value-, reference- and pointer type,
* similar to what the STL does.
* @note client code might define specialisations
* to handle tricky situations (like const_reverse_iter)
*/
template<typename TY>
struct TypeBinding
{
typedef typename TY::pointer pointer;
typedef typename TY::reference reference;
typedef typename TY::value_type value_type;
};
template<typename TY>
struct TypeBinding<TY *>
{
typedef TY value_type;
typedef TY& reference;
typedef TY* pointer;
};
template<typename TY>
struct TypeBinding<const TY *>
{
typedef TY value_type;
typedef const TY& reference;
typedef const TY* pointer;
};
}} // namespace lib
#endif