105 lines
4.0 KiB
C++
105 lines
4.0 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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// Implementation based on the code in libc++
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// http://http://libcxx.llvm.org/
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#ifndef RANGES_V3_ALGORITHM_MINMAX_ELEMENT_HPP
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#define RANGES_V3_ALGORITHM_MINMAX_ELEMENT_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_element_fn
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{
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template<typename I, typename S, typename C = ordered_less, typename P = ident,
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CONCEPT_REQUIRES_(ForwardIterator<I>() && Sentinel<S, I>() &&
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IndirectRelation<C, projected<I, P>>())>
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tagged_pair<tag::min(I), tag::max(I)>
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operator()(I begin, S end, C pred = C{}, P proj = P{}) const
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{
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tagged_pair<tag::min(I), tag::max(I)> result{begin, begin};
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if(begin == end || ++begin == end)
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return result;
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if(invoke(pred, invoke(proj, *begin), invoke(proj, *result.first)))
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result.first = begin;
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else
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result.second = begin;
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while(++begin != end)
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{
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I tmp = begin;
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if(++begin == end)
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{
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if(invoke(pred, invoke(proj, *tmp), invoke(proj, *result.first)))
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result.first = tmp;
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else if(!invoke(pred, invoke(proj, *tmp), invoke(proj, *result.second)))
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result.second = tmp;
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break;
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}
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else
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{
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if(invoke(pred, invoke(proj, *begin), invoke(proj, *tmp)))
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{
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if(invoke(pred, invoke(proj, *begin), invoke(proj, *result.first)))
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result.first = begin;
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if(!invoke(pred, invoke(proj, *tmp), invoke(proj, *result.second)))
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result.second = tmp;
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}
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else
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{
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if(invoke(pred, invoke(proj, *tmp), invoke(proj, *result.first)))
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result.first = tmp;
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if(!invoke(pred, invoke(proj, *begin), invoke(proj, *result.second)))
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result.second = begin;
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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 Rng, typename C = ordered_less, typename P = ident,
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typename I = iterator_t<Rng>,
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CONCEPT_REQUIRES_(ForwardRange<Rng>() &&
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IndirectRelation<C, projected<I, P>>())>
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meta::if_<std::is_lvalue_reference<Rng>,
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tagged_pair<tag::min(I), tag::max(I)>,
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dangling<tagged_pair<tag::min(I), tag::max(I)>>>
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operator()(Rng &&rng, C pred = C{}, P proj = P{}) const
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{
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return (*this)(begin(rng), end(rng), std::move(pred), std::move(proj));
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}
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};
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/// \sa `minmax_element_fn`
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/// \ingroup group-algorithms
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RANGES_INLINE_VARIABLE(with_braced_init_args<minmax_element_fn>, minmax_element)
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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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