vortex_sampling_compressor/compressors/
for.rs

1use vortex_array::aliases::hash_set::HashSet;
2use vortex_array::array::PrimitiveArray;
3use vortex_array::stats::trailing_zeros;
4use vortex_array::variants::PrimitiveArrayTrait;
5use vortex_array::{Array, Encoding, EncodingId, IntoArray, IntoArrayVariant};
6use vortex_dtype::match_each_integer_ptype;
7use vortex_error::VortexResult;
8use vortex_fastlanes::{for_compress, FoRArray, FoREncoding};
9
10use crate::compressors::{CompressedArray, CompressionTree, EncodingCompressor};
11use crate::{constants, SamplingCompressor};
12
13#[derive(Debug)]
14pub struct FoRCompressor;
15
16impl EncodingCompressor for FoRCompressor {
17    fn id(&self) -> &str {
18        FoREncoding::ID.as_ref()
19    }
20
21    fn cost(&self) -> u8 {
22        constants::FOR_COST
23    }
24
25    fn can_compress(&self, array: &Array) -> Option<&dyn EncodingCompressor> {
26        // Only support primitive arrays
27        let parray = PrimitiveArray::maybe_from(array)?;
28
29        // Only supports integers
30        if !parray.ptype().is_int() {
31            return None;
32        }
33
34        // For all-null, cannot encode.
35        if parray.validity_mask().ok()?.all_false() {
36            return None;
37        }
38
39        // Nothing for us to do if the min is already zero and tz == 0
40        let shift = trailing_zeros(array);
41        match_each_integer_ptype!(parray.ptype(), |$P| {
42            let min: $P = parray.statistics().compute_min()?;
43            if min == 0 && shift == 0 {
44                return None;
45            }
46        });
47
48        Some(self)
49    }
50
51    fn compress<'a>(
52        &'a self,
53        array: &Array,
54        like: Option<CompressionTree<'a>>,
55        ctx: SamplingCompressor<'a>,
56    ) -> VortexResult<CompressedArray<'a>> {
57        let compressed = for_compress(array.clone().into_primitive()?)?;
58
59        let compressed_child = ctx.named("for_encoded").excluding(self).compress(
60            &compressed.encoded(),
61            like.as_ref().and_then(|l| l.child(0)),
62        )?;
63        Ok(CompressedArray::compressed(
64            FoRArray::try_new(
65                compressed_child.array,
66                compressed.reference_scalar(),
67                compressed.shift(),
68            )
69            .map(|a| a.into_array())?,
70            Some(CompressionTree::new(self, vec![compressed_child.path])),
71            array,
72        ))
73    }
74
75    fn used_encodings(&self) -> HashSet<EncodingId> {
76        HashSet::from([FoREncoding::ID])
77    }
78}
vortex_sampling_compressor/compressors/for.rs

vortex_sampling_compressor/compressors/
for.rs
