leaf_value_access.h

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#ifndef DDL_LEAF_VALUE_ACCESS_CLASS_HEADER
#define DDL_LEAF_VALUE_ACCESS_CLASS_HEADER
 
#include <a_util/base/type_traits.h>
#include <ddl/codec/bitserializer.h>
#include <ddl/codec/codec_index.h>
#include <ddl/codec/data_representation.h>
#include <ddl/codec/leaf_layout.h>
#include <ddl/utilities/std_to_string.h>
 
#include <cstring>
#include <stdexcept>
 
namespace ddl {
namespace codec {

class LeafCodecIndex {
private:
    template <bool ThrowError>
    using throw_error = std::integral_constant<bool, ThrowError>;
 
public:
    LeafCodecIndex() = delete;
    LeafCodecIndex(const CodecIndex& codec_index, ddl::DataRepresentation rep)
    {
        convertToLeafLayout</*throw_error=*/true>(codec_index, _leaf_layout, rep);
    }

    const LeafLayout& getLayout() const noexcept
    {
        return _leaf_layout;
    }

    template <bool ThrowError>
    static bool convertToLeafLayout(const CodecIndex& codec_index,
                                    LeafLayout& leaf_layout,
                                    ddl::DataRepresentation rep)
    {
        if (!checkLeafLayout<ThrowError>(codec_index, rep)) {
            return false;
        }
        return convertToLeafLayout(codec_index, leaf_layout, rep, throw_error<ThrowError>{});
    }
 
private:
    static bool convertToLeafLayout(const CodecIndex& codec_index,
                                    LeafLayout& leaf_layout,
                                    ddl::DataRepresentation rep,
                                    throw_error<false>) noexcept
    {
        const auto& layout = codec_index.getLayout();
        leaf_layout.element_type = static_cast<LeafElementType>(layout.type_info->getType());
        if (rep == DataRepresentation::deserialized) {
            leaf_layout.data_flags = static_cast<uint8_t>(LeafDataRepresentation::deserialized);
            leaf_layout.byte_pos = static_cast<uint32_t>(layout.deserialized.bit_offset / 8);
            if (layout.deserialized.type_bit_size > (std::numeric_limits<uint8_t>::max)()) {
                return false;
            }
            // no bitpos in deserialized representation
            leaf_layout.bit_size = static_cast<uint8_t>(layout.deserialized.type_bit_size);
        }
        else {
            leaf_layout.data_flags |=
                (layout.byte_order == dd::ByteOrder::e_be) ?
                    static_cast<uint8_t>(LeafDataRepresentation::serialized_be) :
                    static_cast<uint8_t>(LeafDataRepresentation::serialized_le);
            leaf_layout.bit_pos = layout.serialized.bit_offset % 8;
            leaf_layout.byte_pos = static_cast<uint32_t>(layout.serialized.bit_offset / 8);
            if (layout.serialized.type_bit_size_used > (std::numeric_limits<uint8_t>::max)()) {
                return false;
            }
            leaf_layout.bit_size = static_cast<uint8_t>(layout.serialized.type_bit_size_used);
            if (layout.serialized.type_bit_size_used == layout.deserialized.type_bit_size &&
                leaf_layout.bit_pos == 0 &&
                layout.byte_order == dd::ByteOrderDefault::getPlatformDefault()) {
                // this means: the same type is used in serialized and deserialized without byteswap
                //            the simple fast memcopy operation can be used
                // switch back to deserialzed option, but keep bytepos!
                leaf_layout.data_flags = static_cast<uint8_t>(LeafDataRepresentation::deserialized);
            }
        }
        return true;
    }

    static bool convertToLeafLayout(const CodecIndex& codec_index,
                                    LeafLayout& leaf_layout,
                                    ddl::DataRepresentation rep,
                                    throw_error<true>)
    {
        if (!convertToLeafLayout(codec_index, leaf_layout, rep, throw_error<false>{})) {
            throw std::runtime_error(
                "element size exceeds maximal bit size for small leaf layout of" +
                std::to_string((std::numeric_limits<uint8_t>::max)()));
        }
        return true;
    }

    template <typename T>
    static bool checkTypeSize(const CodecIndex& codec_index,
                              ddl::DataRepresentation rep,
                              bool exact_check_on_serialized,
                              throw_error<false>) noexcept
    {
        const auto size_to_check = (rep == ddl::DataRepresentation::serialized) ?
                                       (codec_index.getLayout().serialized.type_bit_size / 8) :
                                       (codec_index.getLayout().deserialized.type_bit_size / 8);
        if (rep == ddl::DataRepresentation::serialized && !exact_check_on_serialized) {
            if (sizeof(T) < size_to_check) {
                return false;
            }
        }
        return (sizeof(T) == size_to_check);
    }

    template <typename T>
    static bool checkTypeSize(const CodecIndex& codec_index,
                              ddl::DataRepresentation rep,
                              bool exact_check,
                              throw_error<true>)
    {
        if (!checkTypeSize<T>(codec_index, rep, exact_check, throw_error<false>{})) {
            throw std::runtime_error(
                "Standard datatype is only supported if bit size is not customized. Found "
                "element type with different size to standard!");
        }
        return true;
    }

    template <bool ThrowError>
    static bool checkLeafLayout(const CodecIndex& codec_index, ddl::DataRepresentation rep)
    {
        switch (codec_index.getType()) {
        case ElementType::cet_empty: // fall thru
        case ElementType::cet_sub_codec: {
            if (ThrowError) {
                throw std::runtime_error("Small leaf layouts can only be used for leaf elements!");
            }
            return false;
            break;
        }
        case ElementType::cet_bool: {
            return checkTypeSize<bool>(codec_index, rep, false, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_int8:
        case ElementType::cet_uint8: {
            return checkTypeSize<int8_t>(codec_index, rep, false, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_int16:
        case ElementType::cet_uint16: {
            return checkTypeSize<int16_t>(codec_index, rep, false, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_int32:
        case ElementType::cet_uint32: {
            return checkTypeSize<int32_t>(codec_index, rep, false, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_float: {
            return checkTypeSize<int32_t>(codec_index, rep, true, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_int64:
        case ElementType::cet_uint64: {
            return checkTypeSize<int64_t>(codec_index, rep, false, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_double: {
            return checkTypeSize<int64_t>(codec_index, rep, true, throw_error<ThrowError>{});
            break;
        }
        case ElementType::cet_user_type: {
            if (ThrowError) {
                throw std::runtime_error(
                    "user supported types are not supported in small leaf layout");
            }
            else {
                return false;
            }
        }
        }
        return true;
    }
    LeafLayout _leaf_layout;
};
 
#if defined(__GNUC__) && (__GNUC__ == 5) && defined(__QNX__)
#pragma GCC diagnostic ignored                                                                     \
    "-Wattributes" // standard type attributes are ignored when used in templates
#endif             // defined(__GNUC__) && (__GNUC__ == 5) && defined(__QNX__)
 
namespace detail {
 
template <typename ValueType>
struct SupportedLeafValueTypeExplicit
    : public std::is_arithmetic<a_util::underlying_type_or_type_t<ValueType>> {};
 
template <typename ElementValueTypeFrom, typename TargetValueTypeTo>
struct SupportTargetTypeConversion
    : public std::integral_constant<
          bool,
          (!std::is_enum<TargetValueTypeTo>::value &&
           a_util::is_explicitly_convertible_to_v<ElementValueTypeFrom, TargetValueTypeTo>) ||
              (std::is_enum<TargetValueTypeTo>::value &&
               !std::is_floating_point<ElementValueTypeFrom>::value)> {};
 
template <typename ValueType>
struct SupportAnyFromFundamentalConversion
    : public std::integral_constant<
          bool,
          a_util::is_explicitly_convertible_to_v<bool, ValueType> ||
              a_util::is_explicitly_convertible_to_v<int8_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<uint8_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<int16_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<uint16_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<int32_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<uint32_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<int64_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<uint64_t, ValueType> ||
              a_util::is_explicitly_convertible_to_v<float, ValueType> ||
              a_util::is_explicitly_convertible_to_v<double, ValueType>> {};

template <typename ElementValueType,
          typename TargetValueType,
          bool conversion_allowed =
              SupportTargetTypeConversion<ElementValueType, TargetValueType>::value>
struct TargetValueConverter {
    static TargetValueType convert(const ElementValueType& element_value)
    {
        return static_cast<TargetValueType>(element_value);
    }
};

template <typename ElementValueType, typename TargetValueType>
struct TargetValueConverter<ElementValueType, TargetValueType, false> {
    static TargetValueType convert(const ElementValueType&)
    {
        static_assert(SupportAnyFromFundamentalConversion<TargetValueType>::value,
                      "The used type must at least convertible from one fundamental type (bool, "
                      "any int, float, double) explicitly!");
        throw std::runtime_error("unsupported type conversion requested");
    }
};
 
template <typename ElementValueTypeTo, typename SourceValueTypeFrom>
struct SupportSourceTypeConversion
    : public std::integral_constant<
          bool,
          (!std::is_enum<SourceValueTypeFrom>::value &&
           a_util::is_explicitly_convertible_to_v<SourceValueTypeFrom, ElementValueTypeTo>) ||
              (std::is_enum<SourceValueTypeFrom>::value &&
               !std::is_floating_point<ElementValueTypeTo>::value)> {};
 
template <typename ValueType>
struct SupportAnyToFundamentalConversion
    : public std::integral_constant<
          bool,
          a_util::is_explicitly_convertible_to_v<ValueType, bool> ||
              a_util::is_explicitly_convertible_to_v<ValueType, int8_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, uint8_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, int16_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, uint16_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, int32_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, uint32_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, int64_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, uint64_t> ||
              a_util::is_explicitly_convertible_to_v<ValueType, float> ||
              a_util::is_explicitly_convertible_to_v<ValueType, double>> {};

template <typename ElementValueType,
          typename SourceValueType,
          bool conversion_allowed =
              SupportSourceTypeConversion<ElementValueType, SourceValueType>::value>
struct SourceValueConverter {
    static bool convert(ElementValueType& element_value, const SourceValueType& value)
    {
        element_value = static_cast<ElementValueType>(value);
        return true;
    }
};

template <typename ElementValueType, typename SourceValueType>
struct SourceValueConverter<ElementValueType, SourceValueType, false> {
    static bool convert(ElementValueType&, const SourceValueType&)
    {
        static_assert(SupportAnyToFundamentalConversion<SourceValueType>::value,
                      "The used type must at least convertible to one fundamental type (bool, any "
                      "int, float, double) explicitly");
        return false;
    }
};

template <typename ElementValueType, typename TargetValueType>
TargetValueType readBytes(const void* data, const size_t& data_size, uint32_t byte_pos)
{
    ElementValueType value;
    if (byte_pos + sizeof(ElementValueType) > data_size) {
        throw std::runtime_error("copy action exceeds buffersize");
    }
    std::memcpy(&value, static_cast<const uint8_t*>(data) + byte_pos, sizeof(ElementValueType));
    return TargetValueConverter<ElementValueType, TargetValueType>::convert(value);
}

template <typename ElementValueType, typename SourceValueType>
void writeBytes(void* data,
                const size_t& data_size,
                uint32_t byte_pos,
                const SourceValueType& source_value)
{
    if (byte_pos + sizeof(ElementValueType) > data_size) {
        throw std::runtime_error("copy action exceeds buffersize");
    }
    else {
        ElementValueType value;
        if (SourceValueConverter<ElementValueType, SourceValueType>::convert(value, source_value)) {
            std::memcpy(static_cast<uint8_t*>(data) + byte_pos, &value, sizeof(ElementValueType));
        }
        else {
            throw std::runtime_error("unsupported type conversion requested");
        }
    }
}

template <typename ElementValueType, typename TargetValueType>
TargetValueType readBits(const void* data,
                         size_t data_size,
                         size_t bit_offset,
                         size_t bit_size,
                         a_util::memory::Endianess byte_order)
{
    ElementValueType value{};
    a_util::memory::BitSerializer bit_reader(const_cast<void*>(data), data_size);
    auto res = bit_reader.read<ElementValueType>(bit_offset, bit_size, &value, byte_order);
    if (res) {
        return TargetValueConverter<ElementValueType, TargetValueType>::convert(value);
    }
    throw std::runtime_error(a_util::result::toString(res));
}

template <typename ElementValueType, typename SourceValueType>
void writeBits(void* data,
               size_t data_size,
               size_t bit_offset,
               size_t bit_size,
               a_util::memory::Endianess byte_order,
               const SourceValueType& source_value)
{
    ElementValueType value{};
    if (SourceValueConverter<ElementValueType, SourceValueType>::convert(value, source_value)) {
        a_util::memory::BitSerializer bit_reader(data, data_size);
        const auto res =
            bit_reader.write<ElementValueType>(bit_offset, bit_size, value, byte_order);
        if (!res) {
            throw std::runtime_error(a_util::result::toString(res));
        }
    }
    else {
        throw std::runtime_error("unsupported type conversion requested");
    }
}

template <typename ValueType>
ValueType readDeserializedBytes(const void* data, const size_t& data_size, const LeafLayout& layout)
{
    switch (layout.element_type) {
    case LeafElementType::let_bool: {
        return readBytes<bool, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_uint8: {
        return readBytes<uint8_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_int8: {
        return readBytes<int8_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_uint16: {
        return readBytes<uint16_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_int16: {
        return readBytes<int16_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_uint32: {
        return readBytes<uint32_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_int32: {
        return readBytes<int32_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_uint64: {
        return readBytes<uint64_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_int64: {
        return readBytes<int64_t, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_float: {
        return readBytes<float, ValueType>(data, data_size, layout.byte_pos);
    }
    case LeafElementType::let_double: {
        return readBytes<double, ValueType>(data, data_size, layout.byte_pos);
    }
    default: // all others are not supported
    {
        break;
    }
    }
    throw std::runtime_error("invalid type");
}

template <typename ValueType>
ValueType readSerializedBits(const void* data, const size_t& data_size, const LeafLayout& layout)
{
    const size_t bit_pos = layout.byte_pos * 8 + layout.bit_pos;
    const size_t bit_size = layout.bit_size;
    const a_util::memory::Endianess byte_order =
        ((layout.data_flags & static_cast<uint8_t>(LeafDataRepresentation::serialized_be)) ==
         static_cast<uint8_t>(LeafDataRepresentation::serialized_be)) ?
            a_util::memory::bit_big_endian :
            a_util::memory::bit_little_endian;
    switch (layout.element_type) {
    case LeafElementType::let_bool: {
        return readBits<bool, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_uint8: {
        return readBits<uint8_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_int8: {
        return readBits<int8_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_uint16: {
        return readBits<uint16_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_int16: {
        return readBits<int16_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_uint32: {
        return readBits<uint32_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_int32: {
        return readBits<int32_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_uint64: {
        return readBits<uint64_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_int64: {
        return readBits<int64_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_float: {
        return readBits<float, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    case LeafElementType::let_double: {
        return readBits<double, ValueType>(data, data_size, bit_pos, bit_size, byte_order);
    }
    default: // all others are not supported
    {
        break;
    }
    }
    throw std::runtime_error("invalid type");
}

template <typename ValueType>
void writeDeserializedBytes(void* data,
                            const size_t& data_size,
                            const LeafLayout& layout,
                            const ValueType& value)
{
    switch (layout.element_type) {
    case LeafElementType::let_bool: {
        return writeBytes<bool, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_uint8: {
        return writeBytes<uint8_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_int8: {
        return writeBytes<int8_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_uint16: {
        return writeBytes<uint16_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_int16: {
        return writeBytes<int16_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_uint32: {
        return writeBytes<uint32_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_int32: {
        return writeBytes<int32_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_uint64: {
        return writeBytes<uint64_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_int64: {
        return writeBytes<int64_t, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_float: {
        return writeBytes<float, ValueType>(data, data_size, layout.byte_pos, value);
    }
    case LeafElementType::let_double: {
        return writeBytes<double, ValueType>(data, data_size, layout.byte_pos, value);
    }
    default: // all others are not supported
    {
        break;
    }
    }
    throw std::runtime_error("invalid type");
}

template <typename ValueType>
void writeSerializedBits(void* data,
                         const size_t& data_size,
                         const LeafLayout& layout,
                         const ValueType& value)
{
    const size_t bit_pos = layout.byte_pos * 8 + layout.bit_pos;
    const size_t bit_size = layout.bit_size;
    const a_util::memory::Endianess byte_order =
        ((layout.data_flags & static_cast<uint8_t>(LeafDataRepresentation::serialized_be)) ==
         static_cast<uint8_t>(LeafDataRepresentation::serialized_be)) ?
            a_util::memory::bit_big_endian :
            a_util::memory::bit_little_endian;
    switch (layout.element_type) {
    case LeafElementType::let_bool: {
        return writeBits<bool, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_uint8: {
        return writeBits<uint8_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_int8: {
        return writeBits<int8_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_uint16: {
        return writeBits<uint16_t, ValueType>(
            data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_int16: {
        return writeBits<int16_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_uint32: {
        return writeBits<uint32_t, ValueType>(
            data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_int32: {
        return writeBits<int32_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_uint64: {
        return writeBits<uint64_t, ValueType>(
            data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_int64: {
        return writeBits<int64_t, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_float: {
        return writeBits<float, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    case LeafElementType::let_double: {
        return writeBits<double, ValueType>(data, data_size, bit_pos, bit_size, byte_order, value);
    }
    default: // all others are not supported
    {
        break;
    }
    }
    throw std::runtime_error("invalid type");
}
 
} // namespace detail
 
#if defined(__GNUC__) && (__GNUC__ == 5) && defined(__QNX__)
#pragma GCC diagnostic warning                                                                     \
    "-Wattributes" // standard type attributes are ignored when used in templates
#endif             // defined(__GNUC__) && (__GNUC__ == 5) && defined(__QNX__)

template <typename ValueType>
struct LeafValueGetter {
    static ValueType getValue(const void* data,
                              const size_t data_size,
                              const LeafLayout& leaf_layout)
    {
        if ((leaf_layout.data_flags & static_cast<uint8_t>(LeafDataRepresentation::serialized)) ==
            static_cast<uint8_t>(LeafDataRepresentation::serialized)) {
            return detail::readSerializedBits<ValueType>(data, data_size, leaf_layout);
        }
        else {
            return detail::readDeserializedBytes<ValueType>(data, data_size, leaf_layout);
        }
    }
};

template <typename ValueType>
struct LeafValueSetter {
    static void setValue(void* data,
                         const size_t data_size,
                         const LeafLayout& leaf_layout,
                         const ValueType& value)
    {
        if ((leaf_layout.data_flags & static_cast<uint8_t>(LeafDataRepresentation::serialized)) ==
            static_cast<uint8_t>(LeafDataRepresentation::serialized)) {
            detail::writeSerializedBits<ValueType>(data, data_size, leaf_layout, value);
        }
        else {
            detail::writeDeserializedBytes<ValueType>(data, data_size, leaf_layout, value);
        }
    }
};
} // namespace codec
} // namespace ddl
 
#ifdef DDL_NO_SUPPORT_FOR_CONSTEXPR_CONDITION
#undef DDL_NO_SUPPORT_FOR_CONSTEXPR_CONDITION
#endif
 
#endif