61 lines
1.1 KiB
C++
61 lines
1.1 KiB
C++
// SPDX-License-Identifier: BSD-2-Clause
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// Copyright CM4all GmbH
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// author: Max Kellermann <mk@cm4all.com>
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#pragma once
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#include <cassert>
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#include <cstddef>
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template<bool enable> class OptionalCounter;
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template<>
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class OptionalCounter<false>
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{
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public:
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constexpr void reset() noexcept {}
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constexpr auto &operator++() noexcept { return *this; }
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constexpr auto &operator--() noexcept { return *this; }
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constexpr auto &operator+=(std::size_t) noexcept { return *this; }
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constexpr auto &operator-=(std::size_t) noexcept { return *this; }
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};
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template<>
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class OptionalCounter<true>
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{
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std::size_t value = 0;
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public:
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constexpr operator std::size_t() const noexcept {
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return value;
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}
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constexpr void reset() noexcept {
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value = 0;
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}
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constexpr auto &operator++() noexcept {
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++value;
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return *this;
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}
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constexpr auto &operator--() noexcept {
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assert(value > 0);
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--value;
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return *this;
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}
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constexpr auto &operator+=(std::size_t n) noexcept {
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value += n;
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return *this;
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}
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constexpr auto &operator-=(std::size_t n) noexcept {
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assert(value >= n);
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value -= n;
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return *this;
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}
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};
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