4.22 sdds::copyDataset

• name:
  sdds::copyDataset, sdds::CopyOptions
• description:
  Stream the remaining pages of a reader to a path without materializing the whole data set. The operation accepts a read projection, writer options, an optional layout transformation, and an optional move-based page transformation that may also reject a page.
• synopsis:
  struct sdds::CopyOptions {  
    sdds::ReadRequest read;  
    sdds::WriterOptions writer;  
    std::function<sdds::Layout(const sdds::Layout &)> transformLayout;  
    std::function<std::optional<sdds::Page>(  
        sdds::Page &&, std::shared_ptr<const sdds::Layout>)> transformPage;  
  };  
   
  void sdds::copyDataset(sdds::Reader &reader,  
                         const std::filesystem::path &output,  
                         sdds::CopyOptions options = {});

• arguments:
  • reader — Source reader positioned before the first page to copy.
  • output — Destination path.
  • options — Projection, writer configuration, and callbacks. The page callback receives the projected page and shared destination layout; an empty optional drops that page.
• return value:
  None.
• exceptions:
  Reader, writer, validation, transformation, and callback exceptions propagate to the caller. If an exception interrupts the operation, the destination may be incomplete.
• see also:
  Sections 4.5, 4.6, and 4.18.