forked from boostorg/range
[boost][range] - Updated begin/end to be protected against accidental ADL to improve compatibility with C++0x. Added any_range which adds type erasure support. Added a type_erased adaptor to utilise the any_range. Implemented the any_iterator using a small buffer optimization to avoid heap usage.
[SVN r67541]
This commit is contained in:
Neil Groves
204
include/boost/range/any_range.hpp
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204
include/boost/range/any_range.hpp
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// Copyright Neil Groves 2010. Use, modification and
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// distribution is subject to the Boost Software License, Version
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// 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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//
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// For more information, see http://www.boost.org/libs/range/
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//
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#ifndef BOOST_RANGE_ANY_RANGE_HPP_INCLUDED
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#define BOOST_RANGE_ANY_RANGE_HPP_INCLUDED
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#include <boost/config.hpp>
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#include <boost/iterator/iterator_categories.hpp>
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#include <boost/iterator/iterator_traits.hpp>
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#include <boost/iterator/iterator_facade.hpp>
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#include <boost/iterator/iterator_adaptor.hpp>
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#include <boost/range/detail/any_iterator.hpp>
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#include <boost/range/reference.hpp>
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#include <boost/range/value_type.hpp>
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#include <boost/range/iterator_range_core.hpp>
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#include <boost/cast.hpp>
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namespace boost
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{
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namespace range_detail
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{
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// If T is use_default, return the result of Default, otherwise
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// return T.
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//
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// This is an implementation artifact used to pick intelligent default
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// values when the user specified boost::use_default as a template
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// parameter.
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template<
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class T,
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class Default
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>
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struct any_range_default_help
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: mpl::eval_if<
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is_same<T, use_default>
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, Default
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, mpl::identity<T>
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>
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{
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};
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template<
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class WrappedRange
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, class Value
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, class Reference
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>
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struct any_range_value_type
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{
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# ifdef BOOST_ITERATOR_REF_CONSTNESS_KILLS_WRITABILITY
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typedef typename any_range_default_help<
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Value
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, mpl::eval_if<
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is_same<Reference, use_default>
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, range_value<
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typename remove_const<WrappedRange>
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::type>
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, remove_reference<Reference>
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>
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>::type type;
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# else
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typedef typename any_range_default_help<
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Value
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, range_value<
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typename remove_const<WrappedRange>
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::type>
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>::type type;
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# endif
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};
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template<
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class Value
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, class Traversal
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, class Reference
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, class Difference
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, class Buffer = use_default
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>
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class any_range
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: public iterator_range<
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any_iterator<
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Value
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, Traversal
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, Reference
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, Difference
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, typename any_range_default_help<
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Buffer
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, mpl::identity<any_iterator_default_buffer>
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>::type
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>
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>
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{
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typedef iterator_range<
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any_iterator<
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Value
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, Traversal
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, Reference
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, Difference
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, typename any_range_default_help<
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Buffer
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, mpl::identity<any_iterator_default_buffer>
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>::type
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>
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> base_type;
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struct enabler {};
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struct disabler {};
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public:
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any_range()
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{
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}
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any_range(const any_range& other)
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: base_type(other)
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{
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}
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template<class WrappedRange>
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any_range(WrappedRange& wrapped_range)
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: base_type(boost::begin(wrapped_range),
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boost::end(wrapped_range))
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{
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}
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template<class WrappedRange>
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any_range(const WrappedRange& wrapped_range)
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: base_type(boost::begin(wrapped_range),
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boost::end(wrapped_range))
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{
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}
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template<
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class OtherValue
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, class OtherTraversal
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, class OtherReference
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, class OtherDifference
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>
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any_range(const any_range<
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OtherValue
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, OtherTraversal
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, OtherReference
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, OtherDifference
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, Buffer
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>& other)
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: base_type(boost::begin(other), boost::end(other))
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{
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}
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template<class Iterator>
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any_range(Iterator first, Iterator last)
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: base_type(first, last)
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{
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}
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};
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template<
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class WrappedRange
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, class Value = use_default
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, class Traversal = use_default
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, class Reference = use_default
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, class Difference = use_default
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, class Buffer = use_default
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>
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struct any_range_type_generator
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{
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BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<WrappedRange> ));
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typedef any_range<
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typename any_range_value_type<
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WrappedRange
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, Value
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, typename any_range_default_help<
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Reference
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, range_reference<WrappedRange>
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>::type
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>::type
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, typename any_range_default_help<
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Traversal
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, iterator_traversal<
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typename range_iterator<WrappedRange>::type
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>
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>::type
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, typename any_range_default_help<
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Reference
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, range_reference<WrappedRange>
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>::type
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, typename any_range_default_help<
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Difference
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, range_difference<WrappedRange>
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>::type
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, typename any_range_default_help<
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Buffer
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, mpl::identity<any_iterator_default_buffer>
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>::type
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> type;
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};
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} // namespace range_detail
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using range_detail::any_range;
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using range_detail::any_range_type_generator;
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} // namespace boost
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#endif // include guard
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