boost/range/size_type.hpp
// Boost.Range library
//
// Copyright Thorsten Ottosen 2003-2004. Use, modification and
// distribution is subject to 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)
//
// For more information, see http://www.boost.org/libs/range/
//
#ifndef BOOST_RANGE_SIZE_TYPE_HPP
#define BOOST_RANGE_SIZE_TYPE_HPP
#if defined(_MSC_VER)
# pragma once
#endif
#include <boost/range/config.hpp>
#include <boost/range/difference_type.hpp>
#include <boost/range/concepts.hpp>
#include <boost/range/has_range_iterator.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/make_unsigned.hpp>
#include <boost/type_traits/remove_const.hpp>
#include <cstddef>
#include <utility>
namespace boost
{
namespace detail
{
//////////////////////////////////////////////////////////////////////////
// default
//////////////////////////////////////////////////////////////////////////
template<typename T>
class has_size_type
{
typedef char no_type;
struct yes_type { char dummy[2]; };
template<typename C>
static yes_type test(BOOST_DEDUCED_TYPENAME C::size_type x);
template<typename C>
static no_type test(...);
public:
static const bool value = sizeof(test<T>(0)) == sizeof(yes_type);
};
template<typename C, typename Enabler=void>
struct range_size_
{
typedef BOOST_DEDUCED_TYPENAME make_unsigned<
BOOST_DEDUCED_TYPENAME range_difference<C>::type
>::type type;
};
template<typename C>
struct range_size_<
C,
BOOST_DEDUCED_TYPENAME ::boost::enable_if<has_size_type<C>, void>::type
>
{
typedef BOOST_DEDUCED_TYPENAME C::size_type type;
};
template<typename C, bool B = range_detail::has_type< range_iterator<C> >::value>
struct range_size
{ };
template<typename C>
struct range_size<C, true>
: range_size_<C>
{ };
}
template< class T >
struct range_size :
detail::range_size<T>
{ };
} // namespace boost
#endif