Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: /// \file iterator.hpp
Chris@16: /// Proto callables for std functions found in \<iterator\>
Chris@16: //
Chris@16: //  Copyright 2012 Eric Niebler. Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_PROTO_FUNCTIONAL_STD_ITERATOR_HPP_EAN_27_08_2012
Chris@16: #define BOOST_PROTO_FUNCTIONAL_STD_ITERATOR_HPP_EAN_27_08_2012
Chris@16: 
Chris@16: #include <iterator>
Chris@16: #include <boost/type_traits/remove_const.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: #include <boost/proto/proto_fwd.hpp>
Chris@16: 
Chris@16: namespace boost { namespace proto { namespace functional
Chris@16: {
Chris@16: 
Chris@16:     // A PolymorphicFunctionObject wrapping std::advance
Chris@16:     struct advance
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         typedef void result_type;
Chris@16: 
Chris@16:         template<typename InputIterator, typename Distance>
Chris@16:         void operator()(InputIterator &x, Distance n) const
Chris@16:         {
Chris@16:             std::advance(x, n);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     // A PolymorphicFunctionObject wrapping std::distance
Chris@16:     struct distance
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         template<typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template<typename This, typename InputIter1, typename InputIter2>
Chris@16:         struct result<This(InputIter1, InputIter2)>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename std::iterator_traits<
Chris@16:                     typename boost::remove_const<
Chris@16:                         typename boost::remove_reference<InputIter1>::type
Chris@16:                     >::type
Chris@16:                 >::difference_type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename InputIterator>
Chris@16:         typename std::iterator_traits<InputIterator>::difference_type
Chris@16:         operator()(InputIterator first, InputIterator last) const
Chris@16:         {
Chris@16:             return std::distance(first, last);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     // A PolymorphicFunctionObject wrapping std::next
Chris@16:     struct next
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         template<typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template<typename This, typename ForwardIterator>
Chris@16:         struct result<This(ForwardIterator)>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename boost::remove_const<
Chris@16:                     typename boost::remove_reference<ForwardIterator>::type
Chris@16:                 >::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename This, typename ForwardIterator, typename Distance>
Chris@16:         struct result<This(ForwardIterator, Distance)>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename boost::remove_const<
Chris@16:                     typename boost::remove_reference<ForwardIterator>::type
Chris@16:                 >::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename ForwardIterator>
Chris@16:         ForwardIterator operator()(ForwardIterator x) const
Chris@16:         {
Chris@16:             return std::advance(
Chris@16:                 x
Chris@16:               , static_cast<typename std::iterator_traits<ForwardIterator>::difference_type>(1)
Chris@16:             );
Chris@16:         }
Chris@16: 
Chris@16:         template<typename ForwardIterator>
Chris@16:         ForwardIterator operator()(
Chris@16:             ForwardIterator x
Chris@16:           , typename std::iterator_traits<ForwardIterator>::difference_type n
Chris@16:         ) const
Chris@16:         {
Chris@16:             return std::advance(x, n);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     // A PolymorphicFunctionObject wrapping std::prior
Chris@16:     struct prior
Chris@16:     {
Chris@16:         BOOST_PROTO_CALLABLE()
Chris@16: 
Chris@16:         template<typename Sig>
Chris@16:         struct result;
Chris@16: 
Chris@16:         template<typename This, typename BidirectionalIterator>
Chris@16:         struct result<This(BidirectionalIterator)>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename boost::remove_const<
Chris@16:                     typename boost::remove_reference<BidirectionalIterator>::type
Chris@16:                 >::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename This, typename BidirectionalIterator, typename Distance>
Chris@16:         struct result<This(BidirectionalIterator, Distance)>
Chris@16:         {
Chris@16:             typedef
Chris@16:                 typename boost::remove_const<
Chris@16:                     typename boost::remove_reference<BidirectionalIterator>::type
Chris@16:                 >::type
Chris@16:             type;
Chris@16:         };
Chris@16: 
Chris@16:         template<typename BidirectionalIterator>
Chris@16:         BidirectionalIterator operator()(BidirectionalIterator x) const
Chris@16:         {
Chris@16:             return std::advance(
Chris@16:                 x
Chris@16:               , -static_cast<typename std::iterator_traits<BidirectionalIterator>::difference_type>(1)
Chris@16:             );
Chris@16:         }
Chris@16: 
Chris@16:         template<typename BidirectionalIterator>
Chris@16:         BidirectionalIterator operator()(
Chris@16:             BidirectionalIterator x
Chris@16:           , typename std::iterator_traits<BidirectionalIterator>::difference_type n
Chris@16:         ) const
Chris@16:         {
Chris@16:             return std::advance(x, -n);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16: }}}
Chris@16: 
Chris@16: #endif