Differential D19566 Diff 55036 contrib/libcxxabi/src/demangle/Utility.h

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contrib/libcxxabi/src/demangle/Utility.h

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				//===--- Utility.h ----------------------------------------------- C++ --===//
				//
				// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
				// See https://llvm.org/LICENSE.txt for license information.
				// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
				//
				//===----------------------------------------------------------------------===//
				//
				// Provide some utility classes for use in the demangler(s).
				//
				//===----------------------------------------------------------------------===//

				#ifndef DEMANGLE_UTILITY_H
				#define DEMANGLE_UTILITY_H

				#include "StringView.h"
				#include <cstdint>
				#include <cstdlib>
				#include <cstring>
				#include <iterator>
				#include <limits>

				DEMANGLE_NAMESPACE_BEGIN

				// Stream that AST nodes write their string representation into after the AST
				// has been parsed.
				class OutputStream {
				char *Buffer;
				size_t CurrentPosition;
				size_t BufferCapacity;

				// Ensure there is at least n more positions in buffer.
				void grow(size_t N) {
				if (N + CurrentPosition >= BufferCapacity) {
				BufferCapacity *= 2;
				if (BufferCapacity < N + CurrentPosition)
				BufferCapacity = N + CurrentPosition;
				Buffer = static_cast<char *>(std::realloc(Buffer, BufferCapacity));
				if (Buffer == nullptr)
				std::terminate();
				}
				}

				void writeUnsigned(uint64_t N, bool isNeg = false) {
				// Handle special case...
				if (N == 0) {
				*this << '0';
				return;
				}

				char Temp[21];
				char *TempPtr = std::end(Temp);

				while (N) {
				*--TempPtr = '0' + char(N % 10);
				N /= 10;
				}

				// Add negative sign...
				if (isNeg)
				*--TempPtr = '-';
				this->operator<<(StringView(TempPtr, std::end(Temp)));
				}

				public:
				OutputStream(char *StartBuf, size_t Size)
				: Buffer(StartBuf), CurrentPosition(0), BufferCapacity(Size) {}
				OutputStream() = default;
				void reset(char *Buffer_, size_t BufferCapacity_) {
				CurrentPosition = 0;
				Buffer = Buffer_;
				BufferCapacity = BufferCapacity_;
				}

				/// If a ParameterPackExpansion (or similar type) is encountered, the offset
				/// into the pack that we're currently printing.
				unsigned CurrentPackIndex = std::numeric_limits<unsigned>::max();
				unsigned CurrentPackMax = std::numeric_limits<unsigned>::max();

				OutputStream &operator+=(StringView R) {
				size_t Size = R.size();
				if (Size == 0)
				return *this;
				grow(Size);
				std::memmove(Buffer + CurrentPosition, R.begin(), Size);
				CurrentPosition += Size;
				return *this;
				}

				OutputStream &operator+=(char C) {
				grow(1);
				Buffer[CurrentPosition++] = C;
				return *this;
				}

				OutputStream &operator<<(StringView R) { return (*this += R); }

				OutputStream &operator<<(char C) { return (*this += C); }

				OutputStream &operator<<(long long N) {
				if (N < 0)
				writeUnsigned(static_cast<unsigned long long>(-N), true);
				else
				writeUnsigned(static_cast<unsigned long long>(N));
				return *this;
				}

				OutputStream &operator<<(unsigned long long N) {
				writeUnsigned(N, false);
				return *this;
				}

				OutputStream &operator<<(long N) {
				return this->operator<<(static_cast<long long>(N));
				}

				OutputStream &operator<<(unsigned long N) {
				return this->operator<<(static_cast<unsigned long long>(N));
				}

				OutputStream &operator<<(int N) {
				return this->operator<<(static_cast<long long>(N));
				}

				OutputStream &operator<<(unsigned int N) {
				return this->operator<<(static_cast<unsigned long long>(N));
				}

				size_t getCurrentPosition() const { return CurrentPosition; }
				void setCurrentPosition(size_t NewPos) { CurrentPosition = NewPos; }

				char back() const {
				return CurrentPosition ? Buffer[CurrentPosition - 1] : '\0';
				}

				bool empty() const { return CurrentPosition == 0; }

				char *getBuffer() { return Buffer; }
				char *getBufferEnd() { return Buffer + CurrentPosition - 1; }
				size_t getBufferCapacity() { return BufferCapacity; }
				};

				template <class T> class SwapAndRestore {
				T &Restore;
				T OriginalValue;
				bool ShouldRestore = true;

				public:
				SwapAndRestore(T &Restore_) : SwapAndRestore(Restore_, Restore_) {}

				SwapAndRestore(T &Restore_, T NewVal)
				: Restore(Restore_), OriginalValue(Restore) {
				Restore = std::move(NewVal);
				}
				~SwapAndRestore() {
				if (ShouldRestore)
				Restore = std::move(OriginalValue);
				}

				void shouldRestore(bool ShouldRestore_) { ShouldRestore = ShouldRestore_; }

				void restoreNow(bool Force) {
				if (!Force && !ShouldRestore)
				return;

				Restore = std::move(OriginalValue);
				ShouldRestore = false;
				}

				SwapAndRestore(const SwapAndRestore &) = delete;
				SwapAndRestore &operator=(const SwapAndRestore &) = delete;
				};

				inline bool initializeOutputStream(char Buf, size_t N, OutputStream &S,
				size_t InitSize) {
				size_t BufferSize;
				if (Buf == nullptr) {
				Buf = static_cast<char *>(std::malloc(InitSize));
				if (Buf == nullptr)
				return false;
				BufferSize = InitSize;
				} else
				BufferSize = *N;

				S.reset(Buf, BufferSize);
				return true;
				}

				DEMANGLE_NAMESPACE_END

				#endif