blob()

std::optional< std::span< const uint8_t > > MayaFlux::Kakshya::Composite::blob ( std::string_view  field_name ) const

noexcept

Borrow the bytes of a fixed or dynamic BLOB field.

Definition at line 367 of file Composite.cpp.

{
    const auto field_index = m_layout->find_field(field_name);
    if (!field_index || !has(field_name))
        return std::nullopt;
    const auto& field = m_layout->fields()[*field_index];
    if (field.type != typeid(std::vector<uint8_t>) && field.type != typeid(detail::CompositeDynamic))
        return std::nullopt;
 
    const auto& rows = std::get<std::vector<uint8_t>>(*m_rows);
    const auto* source = rows.data() + m_index * m_layout->stride_bytes() + field.offset_bytes;
    TextSlice slice;
    if (field.type == typeid(detail::CompositeDynamic)) {
        DynamicCell cell;
        std::memcpy(&cell, source, sizeof(cell));
        if (cell.kind != blob_kind)
            return std::nullopt;
        slice = { cell.payload, cell.length };
    } else {
        std::memcpy(&slice, source, sizeof(slice));
    }
    const auto& blob = std::get<std::vector<uint8_t>>(*m_blob);
    if (slice.offset > blob.size() || slice.length > blob.size() - slice.offset)
        return std::nullopt;
    if (slice.length == 0)
        return std::span<const uint8_t> {};
    return std::span<const uint8_t>(blob.data() + slice.offset, static_cast<size_t>(slice.length));
}

References rows.