vortex_sampling_compressor/compressors/
constant.rs

1use vortex_array::aliases::hash_set::HashSet;
2use vortex_array::array::{ConstantArray, ConstantEncoding};
3use vortex_array::{Array, Encoding, EncodingId, IntoArray};
4use vortex_error::{VortexExpect, VortexResult};
5
6use crate::compressors::{CompressedArray, CompressionTree, EncodingCompressor};
7use crate::{constants, SamplingCompressor};
8
9#[derive(Debug)]
10pub struct ConstantCompressor;
11
12impl EncodingCompressor for ConstantCompressor {
13    fn id(&self) -> &str {
14        ConstantEncoding::ID.as_ref()
15    }
16
17    fn cost(&self) -> u8 {
18        constants::CONSTANT_COST
19    }
20
21    fn can_compress(&self, array: &Array) -> Option<&dyn EncodingCompressor> {
22        array
23            .statistics()
24            .compute_is_constant()?
25            .then_some(self as &dyn EncodingCompressor)
26    }
27
28    fn compress<'a>(
29        &'a self,
30        array: &Array,
31        _like: Option<CompressionTree<'a>>,
32        _ctx: SamplingCompressor<'a>,
33    ) -> VortexResult<CompressedArray<'a>> {
34        Ok(CompressedArray::compressed(
35            ConstantArray::new(
36                array
37                    .as_constant()
38                    .vortex_expect("ConstantCompressor expects constant array"),
39                array.len(),
40            )
41            .into_array(),
42            Some(CompressionTree::flat(self)),
43            array,
44        ))
45    }
46
47    fn used_encodings(&self) -> HashSet<EncodingId> {
48        HashSet::from([ConstantEncoding::ID])
49    }
50}
vortex_sampling_compressor/compressors/constant.rs

vortex_sampling_compressor/compressors/
constant.rs
