forked from boostorg/range
462 lines
16 KiB
C++
Executable File
462 lines
16 KiB
C++
Executable File
// Boost.Range library
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//
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// Copyright Thorsten Ottosen & Pavol Droba 2003-2004. 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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// For more information, see http://www.boost.org/libs/range/
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//
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#ifndef BOOST_RANGE_ITERATOR_RANGE_HPP
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#define BOOST_RANGE_ITERATOR_RANGE_HPP
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#include <boost/range/config.hpp>
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#include <boost/range/begin.hpp>
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#include <boost/range/end.hpp>
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#include <boost/range/empty.hpp>
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#include <boost/range/result_iterator.hpp>
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#include <boost/range/difference_type.hpp>
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#include <boost/iterator/iterator_traits.hpp>
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#include <iterator>
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#include <algorithm>
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#include <ostream>
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#include <cstddef>
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/*! \file
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Defines the \c iterator_class and related functions.
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\c iterator_range is a simple wrapper of iterator pair idiom. It provides
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a rich subset of Container interface.
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*/
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namespace boost {
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// iterator range template class -----------------------------------------//
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//! iterator_range class
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/*!
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An \c iterator_range delimits a range in a sequence by beginning and ending iterators.
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An iterator_range can be passed to an algorithm which requires a sequence as an input.
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For example, the \c toupper() function may be used most frequently on strings,
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but can also be used on iterator_ranges:
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\code
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boost::tolower( find( s, "UPPERCASE STRING" ) );
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\endcode
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Many algorithms working with sequences take a pair of iterators,
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delimiting a working range, as an arguments. The \c iterator_range class is an
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encapsulation of a range identified by a pair of iterators.
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It provides a collection interface,
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so it is possible to pass an instance to an algorithm requiring a collection as an input.
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*/
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template<typename IteratorT>
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class iterator_range
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{
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public:
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//! this type
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typedef iterator_range<IteratorT> type;
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//BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(value_type);
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//! Encapsulated value type
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typedef BOOST_DEDUCED_TYPENAME
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iterator_value<IteratorT>::type value_type;
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//! Difference type
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typedef BOOST_DEDUCED_TYPENAME
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iterator_difference<IteratorT>::type difference_type;
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//! Size type
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typedef std::size_t size_type; // note: must be unsigned
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//! const_iterator type
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/*!
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There is no distinction between const_iterator and iterator.
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These typedefs are provides to fulfill container interface
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*/
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typedef IteratorT const_iterator;
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//! iterator type
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typedef IteratorT iterator;
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iterator_range() : m_Begin( iterator() ), m_End( iterator() ),
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singular( true )
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{ }
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//! Constructor from a pair of iterators
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template< class Iterator >
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iterator_range( Iterator Begin, Iterator End ) :
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m_Begin(Begin), m_End(End), singular(false) {}
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//! Constructor from a Range
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template< class Range >
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iterator_range( const Range& r ) :
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m_Begin( adl_begin( r ) ), m_End( adl_end( r ) ),
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singular(false) {}
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//! Constructor from a Range
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template< class Range >
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iterator_range( Range& r ) :
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m_Begin( adl_begin( r ) ), m_End( adl_end( r ) ),
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singular(false) {}
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template< class Iterator >
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iterator_range& operator=( const iterator_range<Iterator>& r )
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{
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m_Begin = r.begin();
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m_End = r.end();
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//
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// remark: this need not necessarily be true, but it does no harm
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//
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singular = r.empty();
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return *this;
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}
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template< class ForwardRange >
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iterator_range& operator=( ForwardRange& r )
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{
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m_Begin = adl_begin( r );
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m_End = adl_end( r );
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singular = false;
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return *this;
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}
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template< class ForwardRange >
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iterator_range& operator=( const ForwardRange& r )
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{
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m_Begin = adl_begin( r );
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m_End = adl_end( r );
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singular = false;
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return *this;
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}
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//! begin access
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/*!
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Retrieve the begin iterator
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*/
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IteratorT begin() const
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{
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return m_Begin;
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}
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//! end access
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/*!
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Retrieve the end iterator
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*/
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IteratorT end() const
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{
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return m_End;
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}
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//! Size of the range
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/*!
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Retrieve the size of the range
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*/
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size_type size() const
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{
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if( singular )
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return 0;
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return std::distance( m_Begin, m_End );
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}
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bool empty() const
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{
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if( singular )
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return true;
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return m_Begin == m_End;
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}
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//! Safe bool conversion
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/*!
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Check whenever the range is empty.
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Allows to use construction like this:
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\code
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iterator_range r;
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if (!r)
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{
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...
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}
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\endcode
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*/
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typedef iterator (iterator_range::*unspecified_bool_type) () const;
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operator unspecified_bool_type() const
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{
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return empty() ? 0: &iterator_range::end;
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}
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private:
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template< class ForwardRange >
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iterator adl_begin( ForwardRange& r )
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{
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#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
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return boost::begin( r );
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#else
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using boost::begin;
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return begin( r );
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#endif
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}
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template< class ForwardRange >
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iterator adl_end( ForwardRange& r )
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{
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#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
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return boost::end( r );
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#else
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using boost::end;
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return end( r );
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#endif
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}
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private:
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// begin and end iterators
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IteratorT m_Begin;
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IteratorT m_End;
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bool singular;
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};
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// iterator range free-standing operators ---------------------------//
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#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING
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#else
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template< class Iterator >
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inline bool empty( const iterator_range<Iterator>& r )
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{
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//
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// this will preserve the well-defined empty() even
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// though 'r' is singular.
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//
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return r.empty();
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}
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#endif
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//! iterator_range output operator
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/*!
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Output the range to an ostream. Elements are outputed
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in a sequence without separators.
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*/
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template< typename IteratorT, typename Elem, typename Traits >
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inline std::basic_ostream<Elem,Traits>& operator<<(
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std::basic_ostream<Elem, Traits>& Os,
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const iterator_range<IteratorT>& r )
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{
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std::copy( begin(r), end(r), std::ostream_iterator<Elem>(Os));
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return Os;
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}
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//! Comparison operator ( equal )
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/*!
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Compare operands for equality
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*/
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template< class IteratorT, class IteratorT2 >
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inline bool operator==( const iterator_range<IteratorT>& l,
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const iterator_range<IteratorT2>& r )
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{
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return ! (l != r);
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}
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//! Comparison operator ( not-equal )
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/*!
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Compare operands for non-equality
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*/
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template< class IteratorT, class IteratorT2 >
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inline bool operator!=( const iterator_range<IteratorT>& l,
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const iterator_range<IteratorT2>& r )
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{
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return l.begin() != r.begin() || l.end() != r.end();
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}
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// iterator range utilities -----------------------------------------//
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//! iterator_range construct helper
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/*!
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Construct an \c iterator_range from a pair of iterators
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\param Begin A begin iterator
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\param End An end iterator
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\return iterator_range object
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*/
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template< typename IteratorT >
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inline iterator_range< IteratorT >
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make_iterator_range( IteratorT Begin, IteratorT End )
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{
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return iterator_range<IteratorT>( Begin, End );
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}
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/*
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namespace range_detail
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{
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >
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make_sub_range_impl( Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end )
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{
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BOOST_ASSERT( advance_begin >= 0 );
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BOOST_ASSERT( advance_end >= 0 );
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BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type
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new_begin = begin( r ),
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new_end = end( r );
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std::advance( new_begin, advance_begin );
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std::advance( new_end, -advance_end );
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return make_iterator_range( new_begin, new_end );
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}
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >
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make_super_range_impl( Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end )
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{
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BOOST_ASSERT( advance_begin >= 0 );
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BOOST_ASSERT( advance_end >= 0 );
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BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type
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new_begin = begin( r ),
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new_end = end( r );
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std::advance( new_begin, -advance_begin );
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std::advance( new_end, advance_end );
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return make_iterator_range( new_begin, new_end );
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}
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}*/
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#ifdef BOOST_NO_FUNCTION_TEMPLATE_ORDERING
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template< typename Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >
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make_iterator_range( Range& r )
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{
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return iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >
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( begin( r ), end( r ) );
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}
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/*
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >
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make_sub_range( Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end = 0 )
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{
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return range_detail::make_sub_range_impl( r, advance_begin, advance_end );
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}
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_result_iterator<Range>::type >
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make_super_range( Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end = 0 )
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{
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return range_detail::make_super_range_impl( r, advance_begin, advance_end );
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}*/
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#else
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//! iterator_range construct helper
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/*!
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Construct an \c iterator_range from a \c Range containing the begin
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and end iterators.
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*/
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template< class ForwardRange >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type >
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make_iterator_range( ForwardRange& r )
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{
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return iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type >
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( r );
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}
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template< class ForwardRange >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_const_iterator<ForwardRange>::type >
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make_iterator_range( const ForwardRange& r )
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{
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return iterator_range< BOOST_DEDUCED_TYPENAME range_const_iterator<ForwardRange>::type >
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( r );
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}
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/*
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<Range>::type >
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make_sub_range( Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end = 0 )
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{
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return range_detail::make_sub_range_impl( r, advance_begin, advance_end );
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}
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_const_iterator<Range>::type >
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make_sub_range( const Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end = 0 )
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{
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return range_detail::make_sub_range_impl( r, advance_begin, advance_end );
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}
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_iterator<Range>::type >
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make_super_range( Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end = 0 )
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{
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return range_detail::make_super_range_impl( r, advance_begin, advance_end );
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}
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template< class Range >
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inline iterator_range< BOOST_DEDUCED_TYPENAME range_const_iterator<Range>::type >
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make_super_range( const Range& r,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_begin,
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BOOST_DEDUCED_TYPENAME range_difference<Range>::type advance_end = 0 )
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{
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return range_detail::make_super_range_impl( r, advance_begin, advance_end );
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}*/
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#endif // BOOST_NO_FUNCTION_TEMPLATE_ORDERING
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//! copy a range into a sequence
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/*!
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Construct a new sequence of the specified type from the elements
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in the given range
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\param Range An input range
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\return New sequence
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*/
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template< typename SeqT, typename Range >
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inline SeqT copy_range( const Range& r )
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{
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return SeqT( begin( r ), end( r ) );
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}
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//! transform a range into a sequence
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/*!
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Create a new sequence from the elements in the range, transformed
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by a function
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\param Range An input range
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\param Func Transformation function
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\return New sequence
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*/
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template< typename SeqT, typename Range, typename FuncT >
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inline SeqT transform_range( const Range& r, FuncT Func )
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{
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SeqT Seq;
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std::transform( begin( r ), end( r ), std::back_inserter(Seq), Func );
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return Seq;
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}
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} // namespace 'boost'
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#endif
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