OpenAssetTools/src/ZoneCodeGeneratorLib/Parsing/Header/Impl/HeaderLexer.cpp

#include "HeaderLexer.h"

HeaderLexer::HeaderLexer(IParserLineStream* stream)
    : AbstractLexer(stream)
{
    PrepareKeywords();
}

void HeaderLexer::PrepareKeywords()
{
    m_keywords["__declspec"] = HeaderParserValueType::DECLSPEC;
    m_keywords["align"] = HeaderParserValueType::ALIGN;
    m_keywords["alignas"] = HeaderParserValueType::ALIGNAS;
    m_keywords["char"] = HeaderParserValueType::CHAR;
    m_keywords["const"] = HeaderParserValueType::CONST;
    m_keywords["enum"] = HeaderParserValueType::ENUM;
    m_keywords["int"] = HeaderParserValueType::INT;
    m_keywords["long"] = HeaderParserValueType::LONG;
    m_keywords["namespace"] = HeaderParserValueType::NAMESPACE;
    m_keywords["short"] = HeaderParserValueType::SHORT;
    m_keywords["struct"] = HeaderParserValueType::STRUCT;
    m_keywords["typedef"] = HeaderParserValueType::TYPEDEF;
    m_keywords["union"] = HeaderParserValueType::UNION;
    m_keywords["unsigned"] = HeaderParserValueType::UNSIGNED;
}

HeaderParserValue HeaderLexer::GetNextToken()
{
    auto c = NextChar();

    while (c != EOF)
    {
        switch (c)
        {
        case '\"':
        {
            return HeaderParserValue::String(GetPreviousCharacterPos(), new std::string(ReadString()));
        }

        case '<':
        {
            if (!IsLineEnd())
            {
                const auto pos = GetPreviousCharacterPos();
                const auto nextChar = PeekChar();

                if (nextChar == '=')
                {
                    NextChar();
                    return HeaderParserValue::LessEqual(pos);
                }
                if (nextChar == '<')
                {
                    NextChar();
                    return HeaderParserValue::ShiftLeft(pos);
                }
            }

            return HeaderParserValue::Character(GetPreviousCharacterPos(), static_cast<char>(c));
        }

        case '>':
        {
            if (!IsLineEnd())
            {
                const auto pos = GetPreviousCharacterPos();
                const auto nextChar = PeekChar();

                if (nextChar == '=')
                {
                    NextChar();
                    return HeaderParserValue::GreaterEqual(pos);
                }
                if (nextChar == '>')
                {
                    NextChar();
                    return HeaderParserValue::ShiftRight(pos);
                }
            }

            return HeaderParserValue::Character(GetPreviousCharacterPos(), static_cast<char>(c));
        }

        case '=':
        {
            if (NextCharInLineIs('='))
            {
                const auto pos = GetPreviousCharacterPos();
                NextChar();
                return HeaderParserValue::Equals(pos);
            }

            return HeaderParserValue::Character(GetPreviousCharacterPos(), static_cast<char>(c));
        }

        case '&':
        {
            if (NextCharInLineIs('&'))
            {
                const auto pos = GetPreviousCharacterPos();
                NextChar();
                return HeaderParserValue::LogicalAnd(pos);
            }

            return HeaderParserValue::Character(GetPreviousCharacterPos(), static_cast<char>(c));
        }

        case '|':
        {
            if (NextCharInLineIs('|'))
            {
                const auto pos = GetPreviousCharacterPos();
                NextChar();
                return HeaderParserValue::LogicalOr(pos);
            }

            return HeaderParserValue::Character(GetPreviousCharacterPos(), static_cast<char>(c));
        }

        case '!':
        {
            if (NextCharInLineIs('='))
            {
                const auto pos = GetPreviousCharacterPos();
                NextChar();
                return HeaderParserValue::NotEqual(pos);
            }

            return HeaderParserValue::Character(GetPreviousCharacterPos(), static_cast<char>(c));
        }

        default:
        {
            if (isspace(c))
                break;

            const auto pos = GetPreviousCharacterPos();
            if (isdigit(c))
            {
                bool isFloatingPointValue;
                bool hasSignPrefix;
                double doubleValue;
                int integerValue;

                ReadNumber(isFloatingPointValue, hasSignPrefix, doubleValue, integerValue);

                if (isFloatingPointValue)
                    return HeaderParserValue::FloatingPoint(pos, doubleValue);

                return HeaderParserValue::Integer(pos, integerValue);
            }

            if (isalpha(c) || c == '_')
            {
                auto identifier = ReadIdentifier();

                const auto foundKeyword = m_keywords.find(identifier);
                if (foundKeyword != m_keywords.end())
                    return HeaderParserValue::Keyword(pos, foundKeyword->second);

                return HeaderParserValue::Identifier(pos, new std::string(std::move(identifier)));
            }

            return HeaderParserValue::Character(pos, static_cast<char>(c));
        }
        }

        c = NextChar();
    }

    return HeaderParserValue::EndOfFile(TokenPos());
}