Trait lance_encoding::decoder::LogicalPageDecoder

pub trait LogicalPageDecoder: Send {
    // Required methods
    fn wait<'a>(
        &'a mut self,
        num_rows: u32,
        source: &'a mut UnboundedReceiver<Box<dyn LogicalPageDecoder>>
    ) -> BoxFuture<'a, Result<()>>;
    fn drain(&mut self, num_rows: u32) -> Result<NextDecodeTask>;
    fn unawaited(&self) -> u32;
    fn avail(&self) -> u32;
}

A decoder for a field’s worth of data

The decoder is initially “unloaded” (doesn’t have all its data). The Self::wait method should be called to wait for the needed I/O data before attempting to decode any further.

Unlike the other decoder types it is assumed that LogicalPageDecoder is stateful and only Send. This is why we don’t need a rows_to_skip argument in Self::drain

Required Methods

fn wait<'a>( &'a mut self, num_rows: u32, source: &'a mut UnboundedReceiver<Box<dyn LogicalPageDecoder>> ) -> BoxFuture<'a, Result<()>>

Waits for enough data to be loaded to decode num_rows of data

fn drain(&mut self, num_rows: u32) -> Result<NextDecodeTask>

Creates a task to decode num_rows of data into an array

fn unawaited(&self) -> u32

The number of rows that are in the page but haven’t yet been “waited”

fn avail(&self) -> u32

The number of rows that have been “waited” but not yet decoded

Implementors

impl LogicalPageDecoder for BinaryPageDecoder