boost/test/utils/iterator/input_iterator_facade.hpp
// (C) Copyright Gennadiy Rozental 2004-2008.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// See http://www.boost.org/libs/test for the library home page.
//
// File : $RCSfile$
//
// Version : $Revision: 49312 $
//
// Description : Input iterator facade
// ***************************************************************************
#ifndef BOOST_INPUT_ITERATOR_FACADE_HPP_071894GER
#define BOOST_INPUT_ITERATOR_FACADE_HPP_071894GER
// Boost
#include <boost/iterator/iterator_facade.hpp>
#include <boost/test/detail/suppress_warnings.hpp>
//____________________________________________________________________________//
namespace boost {
namespace unit_test {
// ************************************************************************** //
// ************** input_iterator_core_access ************** //
// ************************************************************************** //
class input_iterator_core_access
{
#if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
public:
#else
template <class I, class V, class R, class TC> friend class input_iterator_facade;
#endif
template <class Facade>
static bool get( Facade& f )
{
return f.get();
}
private:
// objects of this class are useless
input_iterator_core_access(); //undefined
};
// ************************************************************************** //
// ************** input_iterator_facade ************** //
// ************************************************************************** //
template<typename Derived,
typename ValueType,
typename Reference = ValueType const&,
typename Traversal = single_pass_traversal_tag>
class input_iterator_facade : public iterator_facade<Derived,ValueType,Traversal,Reference>
{
public:
// Constructor
input_iterator_facade() : m_valid( false ), m_value() {}
protected: // provide access to the Derived
void init()
{
m_valid = true;
increment();
}
// Data members
mutable bool m_valid;
ValueType m_value;
private:
friend class boost::iterator_core_access;
// iterator facade interface implementation
void increment()
{
// we make post-end incrementation indefinetly safe
if( m_valid )
m_valid = input_iterator_core_access::get( *static_cast<Derived*>(this) );
}
Reference dereference() const
{
return m_value;
}
// iterator facade interface implementation
bool equal( input_iterator_facade const& rhs ) const
{
// two invalid iterator equals, inequal otherwise
return !m_valid && !rhs.m_valid;
}
};
} // namespace unit_test
} // namespace boost
//____________________________________________________________________________//
#include <boost/test/detail/enable_warnings.hpp>
#endif // BOOST_INPUT_ITERATOR_FACADE_HPP_071894GER