109 lines
4.3 KiB
C++
109 lines
4.3 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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// Copyright Casey Carter 2015
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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_ALGORITHM_MINMAX_HPP
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#define RANGES_V3_ALGORITHM_MINMAX_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_concepts.hpp>
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#include <range/v3/utility/iterator_traits.hpp>
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#include <range/v3/utility/iterator.hpp>
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#include <range/v3/utility/functional.hpp>
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#include <range/v3/utility/static_const.hpp>
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#include <range/v3/utility/tagged_pair.hpp>
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#include <range/v3/algorithm/tagspec.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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/// \addtogroup group-algorithms
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/// @{
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struct minmax_fn
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{
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template<typename Rng, typename C = ordered_less, typename P = ident,
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typename I = iterator_t<Rng>, typename V = value_type_t<I>,
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typename R = tagged_pair<tag::min(V), tag::max(V)>,
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CONCEPT_REQUIRES_(InputRange<Rng>() && Copyable<V>() &&
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IndirectRelation<C, projected<I, P>>())>
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RANGES_CXX14_CONSTEXPR
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R operator()(Rng &&rng, C pred = C{}, P proj = P{}) const
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{
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auto begin = ranges::begin(rng);
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auto end = ranges::end(rng);
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RANGES_EXPECT(begin != end);
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auto result = R{*begin, *begin};
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if(++begin != end)
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{
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{
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auto && tmp = *begin;
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if(invoke(pred, invoke(proj, tmp), invoke(proj, result.first)))
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result.first = (decltype(tmp) &&) tmp;
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else
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result.second = (decltype(tmp) &&) tmp;
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}
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while(++begin != end)
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{
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V tmp1 = *begin;
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if(++begin == end)
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{
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if(invoke(pred, invoke(proj, tmp1), invoke(proj, result.first)))
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result.first = std::move(tmp1);
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else if(!invoke(pred, invoke(proj, tmp1), invoke(proj, result.second)))
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result.second = std::move(tmp1);
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break;
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}
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auto && tmp2 = *begin;
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if(invoke(pred, invoke(proj, tmp2), invoke(proj, tmp1)))
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{
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if(invoke(pred, invoke(proj, tmp2), invoke(proj, result.first)))
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result.first = (decltype(tmp2) &&) tmp2;
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if(!invoke(pred, invoke(proj, tmp1), invoke(proj, result.second)))
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result.second = std::move(tmp1);
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}
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else
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{
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if(invoke(pred, invoke(proj, tmp1), invoke(proj, result.first)))
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result.first = std::move(tmp1);
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if(!invoke(pred, invoke(proj, tmp2), invoke(proj, result.second)))
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result.second = (decltype(tmp2) &&) tmp2;
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}
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}
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}
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return result;
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}
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template<typename T, typename C = ordered_less, typename P = ident,
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CONCEPT_REQUIRES_(
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IndirectRelation<C, projected<const T *, P>>())>
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constexpr tagged_pair<tag::min(T const &), tag::max(T const &)>
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operator()(T const &a, T const &b, C pred = C{}, P proj = P{}) const
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{
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using R = tagged_pair<tag::min(T const &), tag::max(T const &)>;
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return invoke(pred, invoke(proj, b), invoke(proj, a)) ? R{b, a} : R{a, b};
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}
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};
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/// \sa `minmax_fn`
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/// \ingroup group-algorithms
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RANGES_INLINE_VARIABLE(with_braced_init_args<minmax_fn>, minmax)
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/// @}
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} // namespace v3
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} // namespace ranges
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#endif // include guard
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