vortex_zigzag/
compress.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use vortex_array::IntoArray;
5use vortex_array::arrays::PrimitiveArray;
6use vortex_array::dtype::NativePType;
7use vortex_array::dtype::PType;
8use vortex_array::validity::Validity;
9use vortex_array::vtable::ValidityHelper;
10use vortex_buffer::BufferMut;
11use vortex_error::VortexResult;
12use vortex_error::vortex_bail;
13use vortex_error::vortex_panic;
14use zigzag::ZigZag as ExternalZigZag;
15
16use crate::ZigZagArray;
17
18pub fn zigzag_encode(parray: PrimitiveArray) -> VortexResult<ZigZagArray> {
19    let validity = parray.validity().clone();
20    let encoded = match parray.ptype() {
21        PType::I8 => zigzag_encode_primitive::<i8>(parray.into_buffer_mut(), validity),
22        PType::I16 => zigzag_encode_primitive::<i16>(parray.into_buffer_mut(), validity),
23        PType::I32 => zigzag_encode_primitive::<i32>(parray.into_buffer_mut(), validity),
24        PType::I64 => zigzag_encode_primitive::<i64>(parray.into_buffer_mut(), validity),
25        _ => vortex_bail!(
26            "ZigZag can only encode signed integers, got {}",
27            parray.ptype()
28        ),
29    };
30    ZigZagArray::try_new(encoded.into_array())
31}
32
33fn zigzag_encode_primitive<T: ExternalZigZag + NativePType>(
34    values: BufferMut<T>,
35    validity: Validity,
36) -> PrimitiveArray
37where
38    <T as ExternalZigZag>::UInt: NativePType,
39{
40    PrimitiveArray::new(
41        values.map_each_in_place(|v| T::encode(v)).freeze(),
42        validity,
43    )
44}
45
46pub fn zigzag_decode(parray: PrimitiveArray) -> PrimitiveArray {
47    let validity = parray.validity().clone();
48    match parray.ptype() {
49        PType::U8 => zigzag_decode_primitive::<i8>(parray.into_buffer_mut(), validity),
50        PType::U16 => zigzag_decode_primitive::<i16>(parray.into_buffer_mut(), validity),
51        PType::U32 => zigzag_decode_primitive::<i32>(parray.into_buffer_mut(), validity),
52        PType::U64 => zigzag_decode_primitive::<i64>(parray.into_buffer_mut(), validity),
53        _ => vortex_panic!(
54            "ZigZag can only decode unsigned integers, got {}",
55            parray.ptype()
56        ),
57    }
58}
59
60fn zigzag_decode_primitive<T: ExternalZigZag + NativePType>(
61    values: BufferMut<T::UInt>,
62    validity: Validity,
63) -> PrimitiveArray
64where
65    <T as ExternalZigZag>::UInt: NativePType,
66{
67    PrimitiveArray::new(
68        values.map_each_in_place(|v| T::decode(v)).freeze(),
69        validity,
70    )
71}
72
73#[cfg(test)]
74mod test {
75    use vortex_array::ToCanonical;
76    use vortex_array::assert_arrays_eq;
77
78    use super::*;
79    use crate::ZigZagVTable;
80
81    #[test]
82    fn test_compress_i8() {
83        let compressed = zigzag_encode(PrimitiveArray::from_iter(-100_i8..100)).unwrap();
84        assert!(compressed.is::<ZigZagVTable>());
85        assert_arrays_eq!(
86            compressed.to_primitive(),
87            PrimitiveArray::from_iter(-100_i8..100)
88        );
89    }
90    #[test]
91    fn test_compress_i16() {
92        let compressed = zigzag_encode(PrimitiveArray::from_iter(-100_i16..100)).unwrap();
93        assert!(compressed.is::<ZigZagVTable>());
94        assert_arrays_eq!(
95            compressed.to_primitive(),
96            PrimitiveArray::from_iter(-100_i16..100)
97        );
98    }
99    #[test]
100    fn test_compress_i32() {
101        let compressed = zigzag_encode(PrimitiveArray::from_iter(-100_i32..100)).unwrap();
102        assert!(compressed.is::<ZigZagVTable>());
103        assert_arrays_eq!(
104            compressed.to_primitive(),
105            PrimitiveArray::from_iter(-100_i32..100)
106        );
107    }
108    #[test]
109    fn test_compress_i64() {
110        let compressed = zigzag_encode(PrimitiveArray::from_iter(-100_i64..100)).unwrap();
111        assert!(compressed.is::<ZigZagVTable>());
112        assert_arrays_eq!(
113            compressed.to_primitive(),
114            PrimitiveArray::from_iter(-100_i64..100)
115        );
116    }
117}
vortex_zigzag/compress.rs

vortex_zigzag/
compress.rs
