// Boost.Range library
//
//  Copyright Neil Groves 2009.
//  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_SUB_RANGE_HPP
#define BOOST_RANGE_SUB_RANGE_HPP

#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500))
    #pragma warning( push )
    #pragma warning( disable : 4996 )
#endif

#include <boost/detail/workaround.hpp>
#include <boost/range/config.hpp>
#include <boost/range/iterator_range.hpp>
#include <boost/range/value_type.hpp>
#include <boost/range/size_type.hpp>
#include <boost/range/difference_type.hpp>
#include <boost/range/algorithm/equal.hpp>
#include <boost/assert.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/remove_reference.hpp>

namespace boost
{

    template< class ForwardRange >
    class sub_range : public iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type >
    {
        typedef BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type iterator_t;
        typedef iterator_range< iterator_t  > base;

        typedef BOOST_DEDUCED_TYPENAME base::impl impl;
    public:
        typedef BOOST_DEDUCED_TYPENAME range_value<ForwardRange>::type            value_type;
        typedef BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type         iterator;
        typedef BOOST_DEDUCED_TYPENAME range_iterator<const ForwardRange>::type   const_iterator;
        typedef BOOST_DEDUCED_TYPENAME range_difference<ForwardRange>::type       difference_type;
        typedef BOOST_DEDUCED_TYPENAME range_size<ForwardRange>::type             size_type;
        typedef BOOST_DEDUCED_TYPENAME base::reference                            reference;
        
    public: // for return value of front/back
        typedef BOOST_DEDUCED_TYPENAME 
                boost::mpl::if_< boost::is_reference<reference>,
                                 const BOOST_DEDUCED_TYPENAME boost::remove_reference<reference>::type&, 
                                 reference >::type const_reference;

    public:
        sub_range() : base()
        { }

#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500) )
        sub_range( const sub_range& r )
            : base( static_cast<const base&>( r ) )
        { }
#endif

        template< class ForwardRange2 >
        sub_range( ForwardRange2& r ) :

#if BOOST_WORKAROUND(BOOST_INTEL_CXX_VERSION, <= 800 )
            base( impl::adl_begin( r ), impl::adl_end( r ) )
#else
            base( r )
#endif
        { }

        template< class ForwardRange2 >
        sub_range( const ForwardRange2& r ) :

#if BOOST_WORKAROUND(BOOST_INTEL_CXX_VERSION, <= 800 )
            base( impl::adl_begin( r ), impl::adl_end( r ) )
#else
            base( r )
#endif
        { }

        template< class Iter >
        sub_range( Iter first, Iter last ) :
            base( first, last )
        { }

        template< class ForwardRange2 >
        sub_range& operator=( ForwardRange2& r )
        {
            base::operator=( r );
            return *this;
        }

        template< class ForwardRange2 >
        sub_range& operator=( const ForwardRange2& r )
        {
            base::operator=( r );
            return *this;
        }

        sub_range& operator=( const sub_range& r )
        {
            base::operator=( static_cast<const base&>(r) );
            return *this;
        }

    public:

        iterator        begin()          { return base::begin(); }
        const_iterator  begin() const    { return base::begin(); }
        iterator        end()            { return base::end();   }
        const_iterator  end() const      { return base::end();   }
        difference_type size() const     { return base::size();  }


    public: // convenience
        reference front()
        {
            return base::front();
        }

        const_reference front() const
        {
            return base::front();
        }

        reference back()
        {
            return base::back();
        }

        const_reference back() const
        {
            return base::back();
        }

        reference operator[]( difference_type sz )
        {
            return base::operator[](sz);
        }

        const_reference operator[]( difference_type sz ) const
        {
            return base::operator[](sz);
        }

    };

    template< class ForwardRange, class ForwardRange2 >
    inline bool operator==( const sub_range<ForwardRange>& l,
                            const sub_range<ForwardRange2>& r )
    {
        return boost::equal( l, r );
    }

    template< class ForwardRange, class ForwardRange2 >
    inline bool operator!=( const sub_range<ForwardRange>& l,
                            const sub_range<ForwardRange2>& r )
    {
        return !boost::equal( l, r );
    }

    template< class ForwardRange, class ForwardRange2 >
    inline bool operator<( const sub_range<ForwardRange>& l,
                           const sub_range<ForwardRange2>& r )
    {
        return iterator_range_detail::less_than( l, r );
    }


} // namespace 'boost'

#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500))
    #pragma warning( pop )
#endif

#endif