123 lines
4.2 KiB
C++
123 lines
4.2 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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//===-------------------------- algorithm ---------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef RANGES_V3_ALGORITHM_PARTITION_HPP
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#define RANGES_V3_ALGORITHM_PARTITION_HPP
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#include <meta/meta.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/functional.hpp>
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#include <range/v3/utility/swap.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-concepts
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template<typename I, typename C, typename P = ident>
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using Partitionable = meta::strict_and<
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ForwardIterator<I>,
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Permutable<I>,
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IndirectPredicate<C, projected<I, P>>>;
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/// \addtogroup group-algorithms
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/// @{
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struct partition_fn
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{
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private:
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template<typename I, typename S, typename C, typename P>
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static I impl(I begin, S end, C pred, P proj, concepts::ForwardIterator*)
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{
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while(true)
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{
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if(begin == end)
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return begin;
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if(!invoke(pred, invoke(proj, *begin)))
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break;
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++begin;
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}
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for(I p = begin; ++p != end;)
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{
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if(invoke(pred, invoke(proj, *p)))
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{
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ranges::iter_swap(begin, p);
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++begin;
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}
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}
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return begin;
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}
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template<typename I, typename S, typename C, typename P>
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static I impl(I begin, S end_, C pred, P proj, concepts::BidirectionalIterator*)
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{
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I end = ranges::next(begin, end_);
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while(true)
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{
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while(true)
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{
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if(begin == end)
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return begin;
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if(!invoke(pred, invoke(proj, *begin)))
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break;
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++begin;
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}
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do
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{
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if(begin == --end)
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return begin;
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} while(!invoke(pred, invoke(proj, *end)));
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ranges::iter_swap(begin, end);
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++begin;
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}
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}
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public:
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template<typename I, typename S, typename C, typename P = ident,
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CONCEPT_REQUIRES_(Partitionable<I, C, P>() && Sentinel<S, I>())>
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I operator()(I begin, S end, C pred, P proj = P{}) const
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{
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return partition_fn::impl(std::move(begin), std::move(end), std::move(pred),
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std::move(proj), iterator_concept<I>());
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}
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template<typename Rng, typename C, typename P = ident,
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typename I = iterator_t<Rng>,
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CONCEPT_REQUIRES_(Partitionable<I, C, P>() && Range<Rng>())>
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safe_iterator_t<Rng> operator()(Rng &&rng, C pred, P proj = P{}) const
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{
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return partition_fn::impl(begin(rng), end(rng), std::move(pred),
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std::move(proj), iterator_concept<I>());
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}
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};
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/// \sa `partition_fn`
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/// \ingroup group-algorithms
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RANGES_INLINE_VARIABLE(with_braced_init_args<partition_fn>, partition)
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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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