boost/proto/functional/std/iterator.hpp
/////////////////////////////////////////////////////////////////////////////// /// \file iterator.hpp /// Proto callables for std functions found in \<iterator\> // // Copyright 2012 Eric Niebler. 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) #ifndef BOOST_PROTO_FUNCTIONAL_STD_ITERATOR_HPP_EAN_27_08_2012 #define BOOST_PROTO_FUNCTIONAL_STD_ITERATOR_HPP_EAN_27_08_2012 #include <iterator> #include <boost/type_traits/remove_const.hpp> #include <boost/type_traits/remove_reference.hpp> #include <boost/proto/proto_fwd.hpp> namespace boost { namespace proto { namespace functional { // A PolymorphicFunctionObject wrapping std::advance struct advance { BOOST_PROTO_CALLABLE() typedef void result_type; template<typename InputIterator, typename Distance> void operator()(InputIterator &x, Distance n) const { std::advance(x, n); } }; // A PolymorphicFunctionObject wrapping std::distance struct distance { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename InputIter1, typename InputIter2> struct result<This(InputIter1, InputIter2)> { typedef typename std::iterator_traits< typename boost::remove_const< typename boost::remove_reference<InputIter1>::type >::type >::difference_type type; }; template<typename InputIterator> typename std::iterator_traits<InputIterator>::difference_type operator()(InputIterator first, InputIterator last) const { return std::distance(first, last); } }; // A PolymorphicFunctionObject wrapping std::next struct next { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename ForwardIterator> struct result<This(ForwardIterator)> { typedef typename boost::remove_const< typename boost::remove_reference<ForwardIterator>::type >::type type; }; template<typename This, typename ForwardIterator, typename Distance> struct result<This(ForwardIterator, Distance)> { typedef typename boost::remove_const< typename boost::remove_reference<ForwardIterator>::type >::type type; }; template<typename ForwardIterator> ForwardIterator operator()(ForwardIterator x) const { return std::advance( x , static_cast<typename std::iterator_traits<ForwardIterator>::difference_type>(1) ); } template<typename ForwardIterator> ForwardIterator operator()( ForwardIterator x , typename std::iterator_traits<ForwardIterator>::difference_type n ) const { return std::advance(x, n); } }; // A PolymorphicFunctionObject wrapping std::prior struct prior { BOOST_PROTO_CALLABLE() template<typename Sig> struct result; template<typename This, typename BidirectionalIterator> struct result<This(BidirectionalIterator)> { typedef typename boost::remove_const< typename boost::remove_reference<BidirectionalIterator>::type >::type type; }; template<typename This, typename BidirectionalIterator, typename Distance> struct result<This(BidirectionalIterator, Distance)> { typedef typename boost::remove_const< typename boost::remove_reference<BidirectionalIterator>::type >::type type; }; template<typename BidirectionalIterator> BidirectionalIterator operator()(BidirectionalIterator x) const { return std::advance( x , -static_cast<typename std::iterator_traits<BidirectionalIterator>::difference_type>(1) ); } template<typename BidirectionalIterator> BidirectionalIterator operator()( BidirectionalIterator x , typename std::iterator_traits<BidirectionalIterator>::difference_type n ) const { return std::advance(x, -n); } }; }}} #endif