• String Column Factory

  • make_string_column(...)
  • What are the necessary inputs?
  • Do we need more than one factory for String columns for different inputs?

• String column wrapper type

  • There should be a type, cudf::string_column that is a thin wrapper around cudf::column that encodes behavior unique to string columns, e.g., it abstracts which children are offsets vs characters, etc.
  • Example usage would be something like:

    unique_ptr<cudf::column> col = make_string_column(...);
    
    // String specific view constructable from a `cudf::column`of type STRING
    cudf::string_column_view strings{col}; 
    
    // The wrapper type abstracts the roles of children
    column_view offsets = strings.offsets(); // returns child that holds offsets
    column_view chars = strings.characters(); // returns child that holds characters
    
    // Top-level string specific APIs can accept string_column_views directly
    void string_specific_function(string_column_view strings); 
    
    // wrapper type can provide string specific device functions
    __global__ kernel( string_column_view strings1, string_column_view strings2){
       ...
       // compares string `i` in `strings1` to string `j` in `strings2`
       compare_strings(strings1, i, strings2, j);  
    }