125 lines
3.8 KiB
C++
125 lines
3.8 KiB
C++
/*
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* Copyright (C) 2020 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <wtf/text/StringView.h>
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namespace WTF {
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template<typename T>
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class StringParsingBuffer final {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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using CharacterType = T;
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constexpr StringParsingBuffer() = default;
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constexpr StringParsingBuffer(const CharacterType* characters, unsigned length)
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: m_position { characters }
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, m_end { characters + length }
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{
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ASSERT(characters || !length);
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}
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constexpr StringParsingBuffer(const CharacterType* characters, const CharacterType* end)
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: m_position { characters }
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, m_end { end }
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{
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ASSERT(characters <= end);
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ASSERT(!characters == !end);
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ASSERT(static_cast<size_t>(end - characters) <= std::numeric_limits<unsigned>::max());
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}
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constexpr auto position() const { return m_position; }
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constexpr auto end() const { return m_end; }
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constexpr bool hasCharactersRemaining() const { return m_position < m_end; }
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constexpr bool atEnd() const { return m_position == m_end; }
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constexpr unsigned lengthRemaining() const { return m_end - m_position; }
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StringView stringViewOfCharactersRemaining() { return { m_position, lengthRemaining() }; }
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CharacterType operator[](unsigned i)
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{
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ASSERT(i < lengthRemaining());
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return m_position[i];
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}
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constexpr CharacterType operator*() const
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{
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ASSERT(hasCharactersRemaining());
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return *m_position;
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}
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constexpr void advance()
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{
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ASSERT(hasCharactersRemaining());
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++m_position;
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}
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constexpr void advanceBy(unsigned places)
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{
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ASSERT(places <= lengthRemaining());
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m_position += places;
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}
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constexpr StringParsingBuffer& operator++()
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{
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advance();
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return *this;
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}
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constexpr StringParsingBuffer operator++(int)
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{
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auto result = *this;
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++*this;
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return result;
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}
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constexpr StringParsingBuffer& operator+=(int places)
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{
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advanceBy(places);
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return *this;
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}
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private:
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const CharacterType* m_position { nullptr };
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const CharacterType* m_end { nullptr };
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};
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template<typename StringType, typename Function> decltype(auto) readCharactersForParsing(StringType&& string, Function&& functor)
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{
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if (string.is8Bit())
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return functor(StringParsingBuffer { string.characters8(), string.length() });
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return functor(StringParsingBuffer { string.characters16(), string.length() });
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}
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} // namespace WTF
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using WTF::StringParsingBuffer;
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using WTF::readCharactersForParsing;
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