// Boost.Range library

//

//  Copyright Thorsten Ottosen & Pavol Droba 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_ITERATOR_RANGE_HPP

#define BOOST_RANGE_ITERATOR_RANGE_HPP

// From boost/dynamic_bitset.hpp; thanks to Matthias Troyer for Cray X1 patch.

#include <boost/config.hpp> // Define __STL_CONFIG_H, if appropriate.

#ifndef BOOST_OLD_IOSTREAMS 

# if defined(__STL_CONFIG_H) && \

    !defined (__STL_USE_NEW_IOSTREAMS) && !defined(__crayx1) \

    /**/

#  define BOOST_OLD_IOSTREAMS

# endif

#endif // #ifndef BOOST_OLD_IOSTREAMS

#include <boost/detail/workaround.hpp>

#include <boost/range/functions.hpp>

#include <boost/range/result_iterator.hpp>

#include <boost/range/difference_type.hpp>

#include <boost/iterator/iterator_traits.hpp>    

#include <boost/assert.hpp>

#include <iterator>

#include <algorithm>

#ifndef BOOST_OLD_IOSTREAMS

# include <ostream>

#else

# include <ostream.h>

#endif

#include <cstddef>

/*! \file

    Defines the \c iterator_class and related functions. 

    \c iterator_range is a simple wrapper of iterator pair idiom. It provides

    a rich subset of Container interface.

*/

namespace boost 

{

    namespace iterator_range_detail

    {

        //

        // The functions adl_begin and adl_end are implemented in a separate

        // class for gcc-2.9x

        //

        template<typename IteratorT>

        struct iterator_range_impl {

            template< class ForwardRange >

            static IteratorT adl_begin( ForwardRange& r )

            {

                return IteratorT( boost::begin( r ) );

            }

            template< class ForwardRange >

            static IteratorT adl_end( ForwardRange& r )

            {

                return IteratorT( boost::end( r ) );

            }

        };

        template< class Left, class Right >

        inline bool equal( const Left& l, const Right& r )

        {

            typedef BOOST_DEDUCED_TYPENAME boost::range_size<Left>::type sz_type;

            sz_type l_size = boost::size( l ),

                    r_size = boost::size( r );

            if( l_size != r_size )

                return false;

            return std::equal( boost::begin(l), boost::end(l), 

                               boost::begin(r) );                

        }

        template< class Left, class Right >

        inline bool less_than( const Left& l, const Right& r )

        {                

            return std::lexicographical_compare( boost::begin(l), 

                                                 boost::end(l), 

                                                 boost::begin(r), 

                                                 boost::end(r) );                

        }

        struct range_tag { };

        struct const_range_tag { };

    }

//  iterator range template class -----------------------------------------//

        //! iterator_range class

        /*!

            An \c iterator_range delimits a range in a sequence by beginning and ending iterators. 

            An iterator_range can be passed to an algorithm which requires a sequence as an input. 

            For example, the \c toupper() function may be used most frequently on strings, 

            but can also be used on iterator_ranges: 

            \code

                boost::tolower( find( s, "UPPERCASE STRING" ) );

            \endcode

            Many algorithms working with sequences take a pair of iterators, 

            delimiting a working range, as an arguments. The \c iterator_range class is an 

            encapsulation of a range identified by a pair of iterators. 

            It provides a collection interface, 

            so it is possible to pass an instance to an algorithm requiring a collection as an input. 

        */

        template<typename IteratorT> 

        class iterator_range

        {

        protected: // Used by sub_range

            //! implementation class

            typedef iterator_range_detail::iterator_range_impl<IteratorT> impl;

        public:

            //! this type

            typedef iterator_range<IteratorT> type;

            //BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(value_type);

            //! Encapsulated value type

            typedef BOOST_DEDUCED_TYPENAME 

                iterator_value<IteratorT>::type value_type;

            //! Difference type

            typedef BOOST_DEDUCED_TYPENAME 

                iterator_difference<IteratorT>::type difference_type;

            //! Size type

            typedef std::size_t size_type; // note: must be unsigned

            //! This type

            typedef iterator_range<IteratorT> this_type;

            //! Refence type

            //

            // Needed because value-type is the same for 

            // const and non-const iterators

            //

            typedef BOOST_DEDUCED_TYPENAME

                iterator_reference<IteratorT>::type reference;

            //! const_iterator type

            /*! 

                There is no distinction between const_iterator and iterator.

                These typedefs are provides to fulfill container interface

            */ 

            typedef IteratorT const_iterator;

            //! iterator type

            typedef IteratorT iterator;

            iterator_range() : m_Begin( iterator() ), m_End( iterator() ), 

                               singular( true )

            { }

/*

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))  

            iterator_range( this_type r ) :

            : m_Begin(r.begin()), m_End(r.end())

            { }

            this_type& operator=( this_type r )

            {

                m_Begin = r.begin();

                m_End   = r.end();

                return *this;

            }

#endif

*/            

            //! Constructor from a pair of iterators

            template< class Iterator >

            iterator_range( Iterator Begin, Iterator End ) : 

                m_Begin(Begin), m_End(End), singular(false) {}

            //! Constructor from a Range

            template< class Range >

            iterator_range( const Range& r ) : 

                m_Begin( impl::adl_begin( r ) ), m_End( impl::adl_end( r ) ), 

                singular(false) {}

            //! Constructor from a Range

            template< class Range >

            iterator_range( Range& r ) : 

                m_Begin( impl::adl_begin( r ) ), m_End( impl::adl_end( r ) ), 

                singular(false) {}

            //! Constructor from a Range

            template< class Range >

            iterator_range( const Range& r, iterator_range_detail::const_range_tag ) : 

                m_Begin( impl::adl_begin( r ) ), m_End( impl::adl_end( r ) ), 

                singular(false) {}

            //! Constructor from a Range

            template< class Range >

            iterator_range( Range& r, iterator_range_detail::range_tag ) : 

                m_Begin( impl::adl_begin( r ) ), m_End( impl::adl_end( r ) ), 

                singular(false) {}

            #if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)

            this_type& operator=( const this_type& r )    

            {

                m_Begin  = r.begin(); 

                m_End    = r.end();

                //

                // remark: this need not necessarily be true, but it does no harm

                //

                singular = r.singular;

                return *this;

            }

            #endif

            template< class Iterator >

            iterator_range& operator=( const iterator_range<Iterator>& r )    

            {

                m_Begin  = r.begin(); 

                m_End    = r.end();

                //

                // remark: this need not necessarily be true, but it does no harm

                //

                singular = r.empty();

                return *this;

            }

            template< class ForwardRange >

            iterator_range& operator=( ForwardRange& r )

            {

                m_Begin  = impl::adl_begin( r ); 

                m_End    = impl::adl_end( r );

                singular = false;

                return *this;

            }

            template< class ForwardRange >

            iterator_range& operator=( const ForwardRange& r )

            {

                m_Begin  = impl::adl_begin( r ); 

                m_End    = impl::adl_end( r );

                singular = false;

                return *this;

            }

            IteratorT begin() const 

            { 

                return m_Begin; 

            }

            IteratorT end() const 

            { 

                return m_End; 

            } 

            size_type size() const

            { 

                if( singular )

                    return 0;

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582))

                return std::distance<IteratorT>( m_Begin, m_End );

#else                

                return std::distance( m_Begin, m_End );

#endif                

            }

            bool empty() const

            {

                if( singular )

                    return true;

                return m_Begin == m_End;

            }

#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))  

            operator bool() const

            {

                return !empty();

            }                                    

#else            

            typedef iterator (iterator_range::*unspecified_bool_type) () const;

            operator unspecified_bool_type() const

            {

                return empty() ? 0: &iterator_range::end;

            }

#endif

            bool equal( const iterator_range& r ) const

            {

                return singular == r.singular && m_Begin == r.m_Begin && m_End == r.m_End;

            }

#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING

            bool operator==( const iterator_range& r ) const

            {

                return iterator_range_detail::equal( *this, r );

            }

            bool operator!=( const iterator_range& r ) const

            {

                return !operator==(r);

            }

           bool operator<( const iterator_range& r ) const

           {

                return iterator_range_detail::less_than( *this, r );

           }

#endif            

        public: // convenience

           reference front() const

           {

               BOOST_ASSERT( !empty() );

               return *m_Begin;

           }

           reference back() const

           {

               BOOST_ASSERT( !empty() );

               IteratorT last( m_End );

               return *--last;

           }

           reference operator[]( size_type sz ) const

           {

               //BOOST_STATIC_ASSERT( is_random_access );

               BOOST_ASSERT( sz < size() );

               return m_Begin[sz];

           }

           iterator_range& advance_begin( difference_type n )

           {

               std::advance( m_Begin, n );

               return *this;

           }

           iterator_range& advance_end( difference_type n )

           {

               std::advance( m_End, n );

               return *this;

           }

        private:

            // begin and end iterators

            IteratorT m_Begin;

            IteratorT m_End;

            bool      singular;

        };

//  iterator range free-standing operators ---------------------------//

#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING

#else

        template< class Iterator >

        inline bool empty( const iterator_range<Iterator>& r )

        {

            //

            // this will preserve the well-defined empty() even 

            // though 'r' is singular.

            //

            return r.empty();

        }

#endif

#ifndef BOOST_OLD_IOSTREAMS   

        //! iterator_range output operator

        /*!

            Output the range to an ostream. Elements are outputed

            in a sequence without separators.

        */

        template< typename IteratorT, typename Elem, typename Traits >

        inline std::basic_ostream<Elem,Traits>& operator<<( 

                    std::basic_ostream<Elem, Traits>& Os,

                    const iterator_range<IteratorT>& r )

        {

            std::copy( r.begin(), r.end(), 

                       std::ostream_iterator< BOOST_DEDUCED_TYPENAME 

                                            iterator_value<IteratorT>::type, 

                                              Elem, Traits>(Os) );

            return Os;

        }

#else

        //! iterator_range output operator

        /*!

            Output the range to an ostream. Elements are outputed

            in a sequence without separators.

        */

        template< typename IteratorT >

        inline std::ostream& operator<<( 

                    std::ostream& Os,

                    const iterator_range<IteratorT>& r )

        {

            std::copy( r.begin(), r.end(), std::ostream_iterator<char>(Os));

            return Os;

        }

#endif

        /////////////////////////////////////////////////////////////////////

        // comparison operators

        /////////////////////////////////////////////////////////////////////

        template< class IteratorT, class ForwardRange >

        inline bool operator==( const ForwardRange& l, 

                                const iterator_range<IteratorT>& r )

        {

            return iterator_range_detail::equal( l, r );

        }

        template< class IteratorT, class ForwardRange >

        inline bool operator!=( const ForwardRange& l, 

                                const iterator_range<IteratorT>& r )

        {

            return !iterator_range_detail::equal( l, r );

        }

        template< class IteratorT, class ForwardRange >

        inline bool operator<( const ForwardRange& l, 

                               const iterator_range<IteratorT>& r )

        {

            return iterator_range_detail::less_than( l, r );

        }

#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING

#else

        template< class Iterator1T, class Iterator2T >

        inline bool operator==( const iterator_range<Iterator1T>& l, 

                                const iterator_range<Iterator2T>& r )

        {

            return iterator_range_detail::equal( l, r );

        }

        template< class IteratorT, class ForwardRange >

        inline bool operator==( const iterator_range<IteratorT>& l, 

                                const ForwardRange& r )

        {

            return iterator_range_detail::equal( l, r );

        }

        template< class Iterator1T, class Iterator2T >

        inline bool operator!=( const iterator_range<Iterator1T>& l, 

                                const iterator_range<Iterator2T>& r )

        {

            return !iterator_range_detail::equal( l, r );

        }

        template< class IteratorT, class ForwardRange >

        inline bool operator!=( const iterator_range<IteratorT>& l, 

                                const ForwardRange& r )

        {

            return !iterator_range_detail::equal( l, r );

        }

        template< class Iterator1T, class Iterator2T >

        inline bool operator<( const iterator_range<Iterator1T>& l, 

                               const iterator_range<Iterator2T>& r )

        {

            return iterator_range_detail::less_than( l, r );

        }

        template< class IteratorT, class ForwardRange >

        inline bool operator<( const iterator_range<IteratorT>& l, 

                               const ForwardRange& r )

        {            

            return iterator_range_detail::less_than( l, r );

        }

#endif // BOOST_NO_FUNCTION_TEMPLATE_ORDERING

//  iterator range utilities -----------------------------------------//

        //! iterator_range construct helper 

        /*!

            Construct an \c iterator_range from a pair of iterators

            \param Begin A begin iterator

            \param End An end iterator

            \return iterator_range object

        */

        template< typename IteratorT >

        inline iterator_range< IteratorT > 

        make_iterator_range( IteratorT Begin, IteratorT End ) 

        {   

            return iterator_range<IteratorT>( Begin, End );

        }

#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING

        template< typename Range >

        inline iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >

        make_iterator_range( Range& r ) 

        {   

            return iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >

                ( boost::begin( r ), boost::end( r ) );

        }

#else

        //! iterator_range construct helper

        /*!

            Construct an \c iterator_range from a \c Range containing the begin

            and end iterators.

        */

        template< class ForwardRange >

        inline iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type >

        make_iterator_range( ForwardRange& r ) 

        {   

           return iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type >

                ( r, iterator_range_detail::range_tag() );

        }

        template< class ForwardRange >

        inline iterator_range< BOOST_DEDUCED_TYPENAME range_const_iterator<ForwardRange>::type >

        make_iterator_range( const ForwardRange& r ) 

        {   

           return iterator_range< BOOST_DEDUCED_TYPENAME range_const_iterator<ForwardRange>::type >

                ( r, iterator_range_detail::const_range_tag() );