// Copyright 2020 Hans Dembinski
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_HISTOGRAM_MULTI_INDEX_HPP
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#define BOOST_HISTOGRAM_MULTI_INDEX_HPP
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#include <algorithm>
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#include <boost/histogram/detail/detect.hpp>
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#include <boost/histogram/detail/nonmember_container_access.hpp>
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#include <boost/histogram/fwd.hpp>
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#include <boost/mp11/integer_sequence.hpp>
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#include <boost/throw_exception.hpp>
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#include <initializer_list>
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#include <iterator>
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#include <stdexcept>
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#include <tuple>
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namespace boost {
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namespace histogram {
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/** Holder for multiple axis indices.
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Adapts external iterable, tuple, or explicit list of indices to the same representation.
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*/
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template <std::size_t Size>
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struct multi_index {
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using value_type = axis::index_type;
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using iterator = value_type*;
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using const_iterator = const value_type*;
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static multi_index create(std::size_t s) {
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if (s != size())
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BOOST_THROW_EXCEPTION(std::invalid_argument("size does not match static size"));
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return multi_index(priv_tag{});
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}
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template <class... Is>
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multi_index(axis::index_type i, Is... is)
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: multi_index(std::initializer_list<axis::index_type>{
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i, static_cast<axis::index_type>(is)...}) {}
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template <class... Is>
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multi_index(const std::tuple<axis::index_type, Is...>& is)
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: multi_index(is, mp11::make_index_sequence<(1 + sizeof...(Is))>{}) {}
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template <class Iterable, class = detail::requires_iterable<Iterable>>
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multi_index(const Iterable& is) {
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if (detail::size(is) != size())
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BOOST_THROW_EXCEPTION(std::invalid_argument("no. of axes != no. of indices"));
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using std::begin;
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using std::end;
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std::copy(begin(is), end(is), data_);
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}
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iterator begin() noexcept { return data_; }
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iterator end() noexcept { return data_ + size(); }
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const_iterator begin() const noexcept { return data_; }
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const_iterator end() const noexcept { return data_ + size(); }
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static constexpr std::size_t size() noexcept { return Size; }
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private:
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struct priv_tag {};
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multi_index(priv_tag) {}
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template <class T, std::size_t... Is>
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multi_index(const T& is, mp11::index_sequence<Is...>)
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: multi_index(static_cast<axis::index_type>(std::get<Is>(is))...) {}
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axis::index_type data_[size()];
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};
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template <>
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struct multi_index<static_cast<std::size_t>(-1)> {
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using value_type = axis::index_type;
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using iterator = value_type*;
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using const_iterator = const value_type*;
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static multi_index create(std::size_t s) { return multi_index(priv_tag{}, s); }
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template <class... Is>
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multi_index(axis::index_type i, Is... is)
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: multi_index(std::initializer_list<axis::index_type>{
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i, static_cast<axis::index_type>(is)...}) {}
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template <class... Is>
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multi_index(const std::tuple<axis::index_type, Is...>& is)
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: multi_index(is, mp11::make_index_sequence<(1 + sizeof...(Is))>{}) {}
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template <class Iterable, class = detail::requires_iterable<Iterable>>
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multi_index(const Iterable& is) : size_(detail::size(is)) {
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using std::begin;
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using std::end;
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std::copy(begin(is), end(is), data_);
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}
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iterator begin() noexcept { return data_; }
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iterator end() noexcept { return data_ + size_; }
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const_iterator begin() const noexcept { return data_; }
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const_iterator end() const noexcept { return data_ + size_; }
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std::size_t size() const noexcept { return size_; }
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private:
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struct priv_tag {};
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multi_index(priv_tag, std::size_t s) : size_(s) {}
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template <class T, std::size_t... Ns>
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multi_index(const T& is, mp11::index_sequence<Ns...>)
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: multi_index(static_cast<axis::index_type>(std::get<Ns>(is))...) {}
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std::size_t size_ = 0;
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static constexpr std::size_t max_size_ = BOOST_HISTOGRAM_DETAIL_AXES_LIMIT;
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axis::index_type data_[max_size_];
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};
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} // namespace histogram
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} // namespace boost
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#endif
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