54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
//===- UnsignedOrNone.h - simple optional index-----*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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/// \file
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/// Defines clang::UnsignedOrNone.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_BASIC_UNSIGNED_OR_NONE_H
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#define LLVM_CLANG_BASIC_UNSIGNED_OR_NONE_H
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#include <cassert>
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#include <optional>
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namespace clang {
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struct UnsignedOrNone {
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constexpr UnsignedOrNone(std::nullopt_t) : Rep(0) {}
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UnsignedOrNone(unsigned Val) : Rep(Val + 1) { assert(operator bool()); }
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UnsignedOrNone(int) = delete;
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constexpr static UnsignedOrNone fromInternalRepresentation(unsigned Rep) {
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return {std::nullopt, Rep};
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}
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constexpr unsigned toInternalRepresentation() const { return Rep; }
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explicit constexpr operator bool() const { return Rep != 0; }
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unsigned operator*() const {
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assert(operator bool());
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return Rep - 1;
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}
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friend constexpr bool operator==(UnsignedOrNone LHS, UnsignedOrNone RHS) {
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return LHS.Rep == RHS.Rep;
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}
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friend constexpr bool operator!=(UnsignedOrNone LHS, UnsignedOrNone RHS) {
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return LHS.Rep != RHS.Rep;
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}
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private:
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constexpr UnsignedOrNone(std::nullopt_t, unsigned Rep) : Rep(Rep) {};
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unsigned Rep;
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};
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} // namespace clang
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#endif // LLVM_CLANG_BASIC_UNSIGNED_OR_NONE_H
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