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