80 lines
2.2 KiB
C++
80 lines
2.2 KiB
C++
// Copyright (c) 2016-2022 Antony Polukhin
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_PFR_DETAIL_SIZE_ARRAY_HPP
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#define BOOST_PFR_DETAIL_SIZE_ARRAY_HPP
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#pragma once
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#include <boost/pfr/detail/config.hpp>
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#include <cstddef> // metaprogramming stuff
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namespace boost { namespace pfr { namespace detail {
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///////////////////// Array that has the constexpr
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template <std::size_t N>
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struct size_array { // libc++ misses constexpr on operator[]
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typedef std::size_t type;
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std::size_t data[N];
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static constexpr std::size_t size() noexcept { return N; }
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constexpr std::size_t count_nonzeros() const noexcept {
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std::size_t count = 0;
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for (std::size_t i = 0; i < size(); ++i) {
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if (data[i]) {
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++ count;
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}
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}
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return count;
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}
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constexpr std::size_t count_from_opening_till_matching_parenthis_seq(std::size_t from, std::size_t opening_parenthis, std::size_t closing_parenthis) const noexcept {
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if (data[from] != opening_parenthis) {
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return 0;
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}
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std::size_t unclosed_parnthesis = 0;
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std::size_t count = 0;
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for (; ; ++from) {
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if (data[from] == opening_parenthis) {
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++ unclosed_parnthesis;
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} else if (data[from] == closing_parenthis) {
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-- unclosed_parnthesis;
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}
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++ count;
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if (unclosed_parnthesis == 0) {
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return count;
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}
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}
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return count;
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}
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};
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template <>
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struct size_array<0> { // libc++ misses constexpr on operator[]
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typedef std::size_t type;
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std::size_t data[1];
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static constexpr std::size_t size() noexcept { return 0; }
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constexpr std::size_t count_nonzeros() const noexcept {
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return 0;
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}
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};
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template <std::size_t I, std::size_t N>
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constexpr std::size_t get(const size_array<N>& a) noexcept {
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static_assert(I < N, "====================> Boost.PFR: Array index out of bounds");
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return a.data[I];
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}
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}}} // namespace boost::pfr::detail
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#endif // BOOST_PFR_DETAIL_SIZE_ARRAY_HPP
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