vortex_array/arrays/slice/
vtable.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use std::fmt::Debug;
5use std::fmt::Formatter;
6use std::hash::Hash;
7use std::hash::Hasher;
8use std::ops::Range;
9
10use vortex_error::VortexExpect;
11use vortex_error::VortexResult;
12use vortex_error::vortex_bail;
13use vortex_error::vortex_ensure;
14use vortex_error::vortex_panic;
15use vortex_session::VortexSession;
16
17use crate::AnyCanonical;
18use crate::ArrayEq;
19use crate::ArrayHash;
20use crate::ArrayRef;
21use crate::Canonical;
22use crate::DynArray;
23use crate::Precision;
24use crate::arrays::slice::array::SliceArray;
25use crate::arrays::slice::rules::PARENT_RULES;
26use crate::buffer::BufferHandle;
27use crate::dtype::DType;
28use crate::executor::ExecutionCtx;
29use crate::executor::ExecutionStep;
30use crate::scalar::Scalar;
31use crate::serde::ArrayChildren;
32use crate::stats::StatsSetRef;
33use crate::validity::Validity;
34use crate::vtable;
35use crate::vtable::ArrayId;
36use crate::vtable::OperationsVTable;
37use crate::vtable::VTable;
38use crate::vtable::ValidityVTable;
39
40vtable!(Slice);
41
42#[derive(Debug)]
43pub struct SliceVTable;
44
45impl SliceVTable {
46    pub const ID: ArrayId = ArrayId::new_ref("vortex.slice");
47}
48
49impl VTable for SliceVTable {
50    type Array = SliceArray;
51    type Metadata = SliceMetadata;
52    type OperationsVTable = Self;
53    type ValidityVTable = Self;
54    fn id(_array: &Self::Array) -> ArrayId {
55        SliceVTable::ID
56    }
57
58    fn len(array: &SliceArray) -> usize {
59        array.range.len()
60    }
61
62    fn dtype(array: &SliceArray) -> &DType {
63        array.child.dtype()
64    }
65
66    fn stats(array: &SliceArray) -> StatsSetRef<'_> {
67        array.stats.to_ref(array.as_ref())
68    }
69
70    fn array_hash<H: Hasher>(array: &SliceArray, state: &mut H, precision: Precision) {
71        array.child.array_hash(state, precision);
72        array.range.start.hash(state);
73        array.range.end.hash(state);
74    }
75
76    fn array_eq(array: &SliceArray, other: &SliceArray, precision: Precision) -> bool {
77        array.child.array_eq(&other.child, precision) && array.range == other.range
78    }
79
80    fn nbuffers(_array: &Self::Array) -> usize {
81        0
82    }
83
84    fn buffer(_array: &Self::Array, _idx: usize) -> BufferHandle {
85        vortex_panic!("SliceArray has no buffers")
86    }
87
88    fn buffer_name(_array: &Self::Array, _idx: usize) -> Option<String> {
89        None
90    }
91
92    fn nchildren(_array: &Self::Array) -> usize {
93        1
94    }
95
96    fn child(array: &Self::Array, idx: usize) -> ArrayRef {
97        match idx {
98            0 => array.child.clone(),
99            _ => vortex_panic!("SliceArray child index {idx} out of bounds"),
100        }
101    }
102
103    fn child_name(_array: &Self::Array, idx: usize) -> String {
104        match idx {
105            0 => "child".to_string(),
106            _ => vortex_panic!("SliceArray child_name index {idx} out of bounds"),
107        }
108    }
109
110    fn metadata(array: &Self::Array) -> VortexResult<Self::Metadata> {
111        Ok(SliceMetadata(array.range.clone()))
112    }
113
114    fn serialize(_metadata: Self::Metadata) -> VortexResult<Option<Vec<u8>>> {
115        // TODO(joe): make this configurable
116        vortex_bail!("Slice array is not serializable")
117    }
118
119    fn deserialize(
120        _bytes: &[u8],
121        _dtype: &DType,
122        _len: usize,
123        _buffers: &[BufferHandle],
124        _session: &VortexSession,
125    ) -> VortexResult<Self::Metadata> {
126        vortex_bail!("Slice array is not serializable")
127    }
128
129    fn build(
130        dtype: &DType,
131        len: usize,
132        metadata: &SliceMetadata,
133        _buffers: &[BufferHandle],
134        children: &dyn ArrayChildren,
135    ) -> VortexResult<Self::Array> {
136        assert_eq!(len, metadata.0.len());
137        let child = children.get(0, dtype, metadata.0.end)?;
138        Ok(SliceArray {
139            child,
140            range: metadata.0.clone(),
141            stats: Default::default(),
142        })
143    }
144
145    fn with_children(array: &mut Self::Array, children: Vec<ArrayRef>) -> VortexResult<()> {
146        vortex_ensure!(
147            children.len() == 1,
148            "SliceArray expects exactly 1 child, got {}",
149            children.len()
150        );
151        array.child = children
152            .into_iter()
153            .next()
154            .vortex_expect("children length already validated");
155        Ok(())
156    }
157
158    fn execute(array: &Self::Array, ctx: &mut ExecutionCtx) -> VortexResult<ExecutionStep> {
159        // Execute the child to get canonical form, then slice it
160        let Some(canonical) = array.child.as_opt::<AnyCanonical>() else {
161            // If the child is not canonical, recurse.
162            return array
163                .child
164                .clone()
165                .execute::<ArrayRef>(ctx)?
166                .slice(array.slice_range().clone())
167                .map(ExecutionStep::Done);
168        };
169
170        // TODO(ngates): we should inline canonical slice logic here.
171        Canonical::from(canonical)
172            .as_ref()
173            .slice(array.range.clone())
174            .map(ExecutionStep::Done)
175    }
176
177    fn reduce_parent(
178        array: &Self::Array,
179        parent: &ArrayRef,
180        child_idx: usize,
181    ) -> VortexResult<Option<ArrayRef>> {
182        PARENT_RULES.evaluate(array, parent, child_idx)
183    }
184}
185impl OperationsVTable<SliceVTable> for SliceVTable {
186    fn scalar_at(array: &SliceArray, index: usize) -> VortexResult<Scalar> {
187        array.child.scalar_at(array.range.start + index)
188    }
189}
190
191impl ValidityVTable<SliceVTable> for SliceVTable {
192    fn validity(array: &SliceArray) -> VortexResult<Validity> {
193        array.child.validity()?.slice(array.range.clone())
194    }
195}
196
197pub struct SliceMetadata(pub(super) Range<usize>);
198
199impl Debug for SliceMetadata {
200    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
201        write!(f, "{}..{}", self.0.start, self.0.end)
202    }
203}
204
205#[cfg(test)]
206mod tests {
207    use vortex_error::VortexResult;
208
209    use crate::DynArray;
210    use crate::IntoArray;
211    use crate::arrays::PrimitiveArray;
212    use crate::arrays::SliceArray;
213    use crate::assert_arrays_eq;
214
215    #[test]
216    fn test_slice_slice() -> VortexResult<()> {
217        // Slice(1..4, Slice(2..8, base)) combines to Slice(3..6, base)
218        let arr = PrimitiveArray::from_iter(0i32..10).into_array();
219        let inner_slice = SliceArray::new(arr, 2..8).into_array();
220        let slice = inner_slice.slice(1..4)?;
221
222        assert_arrays_eq!(slice, PrimitiveArray::from_iter([3i32, 4, 5]));
223
224        Ok(())
225    }
226}
vortex_array/arrays/slice/vtable.rs

vortex_array/arrays/slice/
vtable.rs
