Struct parquet::arrow::array_reader::StructArrayReader

pub struct StructArrayReader { /* fields omitted */ }

Implementation of struct array reader.

Implementations

impl StructArrayReader

pub fn new(
    data_type: ArrowType,
    children: Vec<Box<dyn ArrayReader>>,
    def_level: i16,
    rep_level: i16
) -> Self

Construct struct array reader.

Trait Implementations

impl ArrayReader for StructArrayReader

fn get_data_type(&self) -> &ArrowType

Returns data type. This must be a struct.

fn next_batch(&mut self, batch_size: usize) -> Result<ArrayRef>

Read batch_size struct records.

Definition levels of struct array is calculated as following:

def_levels[i] = min(child1_def_levels[i], child2_def_levels[i], ...,
childn_def_levels[i]);

Repetition levels of struct array is calculated as following:

rep_levels[i] = child1_rep_levels[i];

The null bitmap of struct array is calculated from def_levels:

null_bitmap[i] = (def_levels[i] >= self.def_level);

fn as_any(&self) -> &dyn Any

fn get_def_levels(&self) -> Option<&[i16]>

Returns the definition levels of data from last call of next_batch. The result is used by parent array reader to calculate its own definition levels and repetition levels, so that its parent can calculate null bitmap.

fn get_rep_levels(&self) -> Option<&[i16]>

Return the repetition levels of data from last call of next_batch. The result is used by parent array reader to calculate its own definition levels and repetition levels, so that its parent can calculate null bitmap.