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/*
* Copyright (C) 2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <wtf/text/StringView.h>
namespace WTF {
template<typename T>
class StringParsingBuffer final {
WTF_MAKE_FAST_ALLOCATED;
public:
using CharacterType = T;
constexpr StringParsingBuffer() = default;
constexpr StringParsingBuffer(std::span<const CharacterType> characters LIFETIME_BOUND)
: m_data { characters }
{
ASSERT(m_data.data() || m_data.empty());
}
constexpr auto position() const LIFETIME_BOUND { return m_data.data(); }
constexpr auto end() const LIFETIME_BOUND { return std::to_address(m_data.end()); }
constexpr bool hasCharactersRemaining() const { return !m_data.empty(); }
constexpr bool atEnd() const { return m_data.empty(); }
constexpr size_t lengthRemaining() const { return m_data.size(); }
constexpr void setPosition(std::span<const CharacterType> position)
{
ASSERT(position.data() <= std::to_address(m_data.end()));
ASSERT(std::to_address(position.end()) <= std::to_address(m_data.end()));
m_data = position;
}
StringView stringViewOfCharactersRemaining() const LIFETIME_BOUND { return span(); }
CharacterType consume()
{
ASSERT(hasCharactersRemaining());
auto character = m_data.front();
m_data = m_data.subspan(1);
return character;
}
std::span<const CharacterType> span() const LIFETIME_BOUND { return m_data; }
std::span<const CharacterType> consume(size_t count) LIFETIME_BOUND
{
ASSERT(count <= lengthRemaining());
auto result = m_data;
m_data = m_data.subspan(count);
return result;
}
CharacterType operator[](size_t i) const
{
ASSERT(i < lengthRemaining());
return m_data[i];
}
constexpr CharacterType operator*() const
{
ASSERT(hasCharactersRemaining());
return m_data.front();
}
constexpr void advance()
{
ASSERT(hasCharactersRemaining());
m_data = m_data.subspan(1);
}
constexpr void advanceBy(size_t places)
{
ASSERT(places <= lengthRemaining());
m_data = m_data.subspan(places);
}
constexpr StringParsingBuffer& operator++()
{
advance();
return *this;
}
constexpr StringParsingBuffer operator++(int)
{
auto result = *this;
++*this;
return result;
}
constexpr StringParsingBuffer& operator+=(int places)
{
advanceBy(places);
return *this;
}
private:
std::span<const CharacterType> m_data;
};
template<typename StringType, typename Function> decltype(auto) readCharactersForParsing(StringType&& string, Function&& functor)
{
if (string.is8Bit())
return functor(StringParsingBuffer { string.span8() });
return functor(StringParsingBuffer { string.span16() });
}
} // namespace WTF
using WTF::StringParsingBuffer;
using WTF::readCharactersForParsing;
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