pub trait HybridRleGatherer<O: Clone> {
type Target;
// Required methods
fn target_reserve(&self, target: &mut Self::Target, n: usize);
fn target_num_elements(&self, target: &Self::Target) -> usize;
fn hybridrle_to_target(&self, value: u32) -> ParquetResult<O>;
fn gather_one(
&self,
target: &mut Self::Target,
value: O,
) -> ParquetResult<()>;
fn gather_repeated(
&self,
target: &mut Self::Target,
value: O,
n: usize,
) -> ParquetResult<()>;
// Provided methods
fn gather_slice(
&self,
target: &mut Self::Target,
source: &[u32],
) -> ParquetResult<()> { ... }
fn gather_chunk(
&self,
target: &mut Self::Target,
source: &<u32 as Unpackable>::Unpacked,
) -> ParquetResult<()> { ... }
fn gather_bitpacked_all(
&self,
target: &mut Self::Target,
decoder: Decoder<'_, u32>,
) -> ParquetResult<()> { ... }
fn gather_bitpacked_limited<'a>(
&self,
target: &mut Self::Target,
decoder: Decoder<'a, u32>,
limit: usize,
) -> ParquetResult<BufferedBitpacked<'a>> { ... }
fn gather_bitpacked<'a>(
&self,
target: &mut Self::Target,
decoder: Decoder<'a, u32>,
limit: Option<usize>,
) -> ParquetResult<(usize, Option<HybridRleBuffered<'a>>)> { ... }
}Expand description
Trait that describes what to do with consumed Hybrid-RLE Encoded values.
This is quite a general trait that provides a lot of open space as to how to handle the
Hybrid-RLE encoded values. There is also the Translator trait that is usually good enough
if you want just want to map values to another set of values and collect them into a vector.
Although, this trait might seem quite over-engineered (it might be), it is very useful for
performance. This allows for usage of the properties that HybridRleDecoder provides and for
definition of efficient procedures for collecting slices, chunks, repeated elements and
bit-packed elements.
The Translator doc-comment has a good description of why this trait is needed.