125 lines
4.7 KiB
C++
125 lines
4.7 KiB
C++
/// \file
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// Range v3 library
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//
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// Copyright Eric Niebler 2013-2014
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// Copyright Gonzalo Brito Gadeschi 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_NUMERIC_PARTIAL_SUM_HPP
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#define RANGES_V3_NUMERIC_PARTIAL_SUM_HPP
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#include <meta/meta.hpp>
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#include <range/v3/begin_end.hpp>
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#include <range/v3/range_traits.hpp>
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#include <range/v3/range_concepts.hpp>
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#include <range/v3/algorithm/tagspec.hpp>
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#include <range/v3/utility/functional.hpp>
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#include <range/v3/utility/iterator_traits.hpp>
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#include <range/v3/utility/iterator_concepts.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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template<typename I, typename O, typename BOp = plus, typename P = ident,
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typename V = value_type_t<I>,
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typename X = concepts::Invocable::result_t<P&, V>,
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typename Y = concepts::Invocable::result_t<BOp&, X, X>>
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using PartialSummable = meta::strict_and<
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InputIterator<I>,
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OutputIterator<O, X>,
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Invocable<P&, V>,
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CopyConstructible<uncvref_t<X>>,
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Invocable<BOp&, X, X>,
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Assignable<uncvref_t<X>&, Y>>;
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struct partial_sum_fn
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{
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template<typename I, typename S, typename O, typename BOp = plus,
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typename P = ident,
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CONCEPT_REQUIRES_(Sentinel<S, I>() && PartialSummable<I, O, BOp, P>())>
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tagged_pair<tag::in(I), tag::out(O)>
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operator()(I begin, S end, O result, BOp bop = BOp{}, P proj = P{}) const
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{
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using V = value_type_t<I>;
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using X = concepts::Invocable::result_t<P&, V>;
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coerce<V> v;
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coerce<X> x;
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if(begin != end)
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{
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auto t(x(invoke(proj, v(*begin))));
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*result = t;
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for(++begin, ++result; begin != end; ++begin, ++result)
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{
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t = invoke(bop, t, invoke(proj, *begin));
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*result = t;
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}
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}
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return {begin, result};
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}
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template<typename I, typename S, typename O, typename S2,
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typename BOp = plus, typename P = ident,
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CONCEPT_REQUIRES_(Sentinel<S, I>() && Sentinel<S2, O>() &&
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PartialSummable<I, O, BOp, P>())>
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tagged_pair<tag::in(I), tag::out(O)>
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operator()(I begin, S end, O result, S2 end_result, BOp bop = BOp{}, P proj = P{}) const
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{
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using V = value_type_t<I>;
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using X = concepts::Invocable::result_t<P&, V>;
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coerce<V> v;
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coerce<X> x;
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if(begin != end && result != end_result)
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{
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auto t(x(invoke(proj, v(*begin))));
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*result = t;
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for(++begin, ++result; begin != end && result != end_result;
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++begin, ++result)
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{
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t = invoke(bop, t, invoke(proj, *begin));
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*result = t;
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}
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}
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return {begin, result};
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}
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template<typename Rng, typename ORef, typename BOp = plus,
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typename P = ident, typename I = iterator_t<Rng>,
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typename O = uncvref_t<ORef>,
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CONCEPT_REQUIRES_(Range<Rng>() && PartialSummable<I, O, BOp, P>())>
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tagged_pair<tag::in(safe_iterator_t<Rng>), tag::out(O)>
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operator()(Rng && rng, ORef && result, BOp bop = BOp{}, P proj = P{}) const
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{
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return (*this)(begin(rng), end(rng), std::forward<ORef>(result),
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std::move(bop), std::move(proj));
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}
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template<typename Rng, typename ORng, typename BOp = plus,
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typename P = ident, typename I = iterator_t<Rng>,
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typename O = iterator_t<ORng>,
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CONCEPT_REQUIRES_(Range<Rng>() && Range<ORng>() &&
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PartialSummable<I, O, BOp, P>())>
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tagged_pair<tag::in(safe_iterator_t<Rng>),
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tag::out(safe_iterator_t<ORng>)>
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operator()(Rng && rng, ORng && result, BOp bop = BOp{}, P proj = P{}) const
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{
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return (*this)(begin(rng), end(rng), begin(result), end(result),
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std::move(bop), std::move(proj));
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}
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};
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RANGES_INLINE_VARIABLE(partial_sum_fn, partial_sum)
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}
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}
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#endif
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