boost/spirit/home/support/iterators/detail/input_iterator_policy.hpp
// Copyright (c) 2001 Daniel C. Nuffer
// Copyright (c) 2001-2011 Hartmut Kaiser
//
// 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)
#if !defined(BOOST_SPIRIT_ITERATOR_INPUT_ITERATOR_POLICY_MAR_16_2007_1156AM)
#define BOOST_SPIRIT_ITERATOR_INPUT_ITERATOR_POLICY_MAR_16_2007_1156AM
#include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp>
#include <boost/spirit/home/support/iterators/detail/multi_pass.hpp>
#include <boost/assert.hpp>
#include <iterator> // for std::iterator_traits
namespace boost { namespace spirit { namespace iterator_policies
{
namespace input_iterator_is_valid_test_
{
///////////////////////////////////////////////////////////////////////
template <typename Token>
inline bool token_is_valid(Token const& c)
{
return c ? true : false;
}
}
///////////////////////////////////////////////////////////////////////////
// class input_iterator
// Implementation of the InputPolicy used by multi_pass
//
// The input_iterator encapsulates an input iterator of type T
///////////////////////////////////////////////////////////////////////////
struct input_iterator
{
///////////////////////////////////////////////////////////////////////
template <typename T>
class unique // : public detail::default_input_policy
{
private:
typedef
typename std::iterator_traits<T>::value_type
result_type;
public:
typedef
typename std::iterator_traits<T>::difference_type
difference_type;
typedef
typename std::iterator_traits<T>::difference_type
distance_type;
typedef
typename std::iterator_traits<T>::pointer
pointer;
typedef
typename std::iterator_traits<T>::reference
reference;
typedef result_type value_type;
protected:
unique() {}
explicit unique(T) {}
void swap(unique&) {}
public:
template <typename MultiPass>
static void destroy(MultiPass&) {}
template <typename MultiPass>
static typename MultiPass::reference get_input(MultiPass& mp)
{
return *mp.shared()->input_;
}
template <typename MultiPass>
static void advance_input(MultiPass& mp)
{
++mp.shared()->input_;
}
// test, whether we reached the end of the underlying stream
template <typename MultiPass>
static bool input_at_eof(MultiPass const& mp)
{
static T const end_iter;
return mp.shared()->input_ == end_iter;
}
template <typename MultiPass>
static bool input_is_valid(MultiPass const&, value_type const& t)
{
using namespace input_iterator_is_valid_test_;
return token_is_valid(t);
}
// no unique data elements
};
///////////////////////////////////////////////////////////////////////
template <typename T>
struct shared
{
explicit shared(T const& input) : input_(input) {}
T input_;
};
};
}}}
#endif