48 lines
1.2 KiB
C++
48 lines
1.2 KiB
C++
/// \file
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// Range v3 library
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//
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// Copyright Eric Niebler 2014
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//
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// Use, modification and distribution is subject to the
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// Boost Software License, Version 1.0. (See accompanying
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// 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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// Project home: https://github.com/ericniebler/range-v3
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//
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#ifndef RANGES_V3_BACK_HPP
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#define RANGES_V3_BACK_HPP
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#include <range/v3/range_fwd.hpp>
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#include <range/v3/begin_end.hpp>
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#include <range/v3/range_concepts.hpp>
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#include <range/v3/range_traits.hpp>
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#include <range/v3/utility/iterator.hpp>
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#include <range/v3/utility/static_const.hpp>
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namespace ranges
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{
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inline namespace v3
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{
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/// \ingroup group-core
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struct back_fn
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{
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/// \return `*prev(end(rng))`
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template<typename Rng,
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CONCEPT_REQUIRES_(BoundedRange<Rng>() && BidirectionalRange<Rng>())>
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RANGES_CXX14_CONSTEXPR
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range_reference_t<Rng> operator()(Rng &&rng) const
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{
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return *prev(end(rng));
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}
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};
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/// \ingroup group-core
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/// \sa `back_fn`
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RANGES_INLINE_VARIABLE(back_fn, back)
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}
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}
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#endif
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