58 lines
1.5 KiB
C++
58 lines
1.5 KiB
C++
/*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* Copyright 2019 Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include "base.hpp"
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#include <cstddef>
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///////////////////////////////////////////////////////////////////////////////
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namespace cruft::coord {
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/// A StrictWeakOrder over coordinate types.
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template <typename CoordT = void>
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struct ordering;
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/// A StrictWeakOrder over coordinate types.
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///
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/// The comparison operates across successive elements of the two
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/// coordinates.
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template <typename CoordT>
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struct ordering {
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bool operator() (
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CoordT const &a,
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CoordT const &b
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) const noexcept {
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for (std::size_t i = 0; i < CoordT::elements; ++i) {
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if (a[i] < b[i])
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return true;
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else if (a[i] > b[i])
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return false;
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}
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return false;
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}
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};
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/// A StrictWeakOrder over coordinate types.
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///
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/// Deduction is deferred until the function is called, in the same way
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/// that std::less<> operates.
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template <>
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struct ordering<void> {
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template <typename CoordT>
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bool operator() (CoordT const &a, CoordT const &b) const noexcept
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{
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return ordering<CoordT> {} (a, b);
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}
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};
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}
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