from_string_details.ipp

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namespace restinio
{

namespace utils
{

namespace details
{

template< typename C >
const C * digits_mapping()
{
    static constexpr C table[] = {
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,

        0xF0, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
            return table;
}

struct int8_parse_traits_t
{
    using type_t = std::int8_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 3;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "128";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "127";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "int8_t";
        return r;
    }
};

struct uint8_parse_traits_t
{
    using type_t = std::uint8_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 3;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "0";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "255";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "uint8_t";
        return r;
    }
};

struct int16_parse_traits_t
{
    using type_t = std::int16_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 5;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "32768";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "32767";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "int16_t";
        return r;
    }
};

struct uint16_parse_traits_t
{
    using type_t = std::uint16_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 5;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "0";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "65535";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "uint16_t";
        return r;
    }
};

struct int32_parse_traits_t
{
    using type_t = std::int32_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 10;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "2147483648";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "2147483647";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "int32_t";
        return r;
    }
};

struct uint32_parse_traits_t
{
    using type_t = std::uint32_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 10;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "0";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "4294967295";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "uint32_t";
        return r;
    }
};

struct int64_parse_traits_t
{
    using type_t = std::int64_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 19;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "9223372036854775808";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "9223372036854775807";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "int64_t";
        return r;
    }
};

struct uint64_parse_traits_t
{
    using type_t = std::uint64_t;

    static constexpr std::size_t
    digits_representation_max_size()
    {
        return 20;
    }

    static const char *
    min_representation()
    {
        static constexpr char r[] = "0";
        return r;
    }

    static const char *
    max_representation()
    {
        static constexpr char r[] = "18446744073709551615";
        return r;
    }

    static const char * type_name()
    {
        static constexpr char r[] = "uint64_t";
        return r;
    }
};

template < typename Integer >
Integer
parse_integer_no_checks(
    const std::uint8_t * const mapping_table,
    const char * data_begin,
    const char * data_end,
    bool apply_minus_sign,
    std::true_type /* is signed */)
{
    Integer result = 0;

    if( apply_minus_sign )
        while( data_begin != data_end )
        {
            result = result*10 - mapping_table[ static_cast< std::size_t >( *data_begin++ ) ];
        }
    else
        while( data_begin != data_end )
        {
            result = result*10 + mapping_table[ static_cast< std::size_t >( *data_begin++ ) ];
        }

    return result;
}

template < typename Integer >
Integer
parse_integer_no_checks(
    const std::uint8_t * const mapping_table,
    const char * data_begin,
    const char * data_end,
    bool ,
    std::false_type /* is signed */ )
{
    Integer result = 0;

    while( data_begin != data_end )
    {
        result = result * 10 + mapping_table[ static_cast< std::size_t >( *data_begin++ ) ];
    }

    return result;
}

template < typename Traits >
typename Traits::type_t
parse_integer( const char * data_begin, const char * data_end )
{
    bool apply_minus_sign = false;
    if( '-' == *data_begin )
    {
        if( !std::is_signed< typename Traits::type_t >::value )
        {
            throw exception_t{
                fmt::format(
                    "invalid {} value: unsigned starts with minus",
                    Traits::type_name() ) };
        }

        // else:
        apply_minus_sign = true;
        ++data_begin;
    }
    else if( '+' == *data_begin )
    {
        ++data_begin;
    }

    const auto representation_size = static_cast< std::size_t >( data_end - data_begin );

    if( 0 == representation_size )
        throw exception_t{ fmt::format( "invalid {} value: empty string", Traits::type_name() ) };

    if( Traits::digits_representation_max_size() < representation_size )
        throw exception_t{
            fmt::format(
                "invalid {} value: max digits for type is {}",
                Traits::type_name(),
                Traits::digits_representation_max_size() ) };

    const std::uint8_t * const mapping_table = digits_mapping< std::uint8_t >();

    if( std::any_of(
            data_begin,
            data_end,
            [&]( auto d ){ return 0xFF == mapping_table[ static_cast< std::size_t >( d ) ]; } ) )
    {
        throw exception_t{
            fmt::format( "invalid {} value: invalid digit", Traits::type_name() ) };
    }

    if( Traits::digits_representation_max_size() == representation_size )
    {
        const char * const posssible_max = apply_minus_sign ?
            Traits::min_representation() : Traits::max_representation();

        if( 0 < std::memcmp( data_begin, posssible_max, representation_size ) )
            throw std::out_of_range{
                fmt::format( "invalid {} value: out of range", Traits::type_name() ) };
    }

    using is_signed_t = typename std::is_signed< typename Traits::type_t >::type;

    return
        parse_integer_no_checks< typename Traits::type_t >(
            mapping_table,
            data_begin,
            data_end,
            apply_minus_sign,
            is_signed_t{} );
}

} /* namespace details */

} /* namespace utils */

} /* namespace restinio */