vortex_array/scalar_fn/fns/cast/
kernel.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright the Vortex contributors
3
4use vortex_error::VortexResult;
5
6use crate::ArrayRef;
7use crate::ExecutionCtx;
8use crate::IntoArray;
9use crate::arrays::scalar_fn::ExactScalarFn;
10use crate::arrays::scalar_fn::ScalarFnArrayView;
11use crate::dtype::DType;
12use crate::kernel::ExecuteParentKernel;
13use crate::matcher::Matcher;
14use crate::optimizer::rules::ArrayParentReduceRule;
15use crate::scalar_fn::fns::cast::Cast;
16use crate::vtable::VTable;
17
18/// Reduce rule for cast: restructure the array without reading buffers.
19///
20/// Encodings implement this to push cast operations through their structure.
21/// For example, RunEnd pushes cast down to its values array, ZigZag transforms
22/// the target dtype to unsigned and pushes to its encoded array.
23///
24/// Returns `Ok(None)` if the rule doesn't apply to this array/dtype combination.
25pub trait CastReduce: VTable {
26    fn cast(array: &Self::Array, dtype: &DType) -> VortexResult<Option<ArrayRef>>;
27}
28
29/// Execute kernel for cast: perform the actual value conversion, potentially reading buffers.
30///
31/// Canonical array types implement this to do the real type conversion work.
32/// For example, PrimitiveArray converts numeric values between types.
33///
34/// Returns `Ok(None)` if this kernel cannot handle the given dtype conversion.
35pub trait CastKernel: VTable {
36    fn cast(
37        array: &Self::Array,
38        dtype: &DType,
39        ctx: &mut ExecutionCtx,
40    ) -> VortexResult<Option<ArrayRef>>;
41}
42
43/// Adapts a [`CastReduce`] impl into an [`ArrayParentReduceRule`] for `ScalarFnArray(Cast, ...)`.
44#[derive(Default, Debug)]
45pub struct CastReduceAdaptor<V>(pub V);
46
47impl<V> ArrayParentReduceRule<V> for CastReduceAdaptor<V>
48where
49    V: CastReduce,
50{
51    type Parent = ExactScalarFn<Cast>;
52
53    fn reduce_parent(
54        &self,
55        array: &V::Array,
56        parent: ScalarFnArrayView<'_, Cast>,
57        _child_idx: usize,
58    ) -> VortexResult<Option<ArrayRef>> {
59        let dtype = parent.options;
60        if array.dtype() == dtype {
61            return Ok(Some(array.clone().into_array()));
62        }
63        <V as CastReduce>::cast(array, dtype)
64    }
65}
66
67/// Adapts a [`CastKernel`] impl into an [`ExecuteParentKernel`] for `ScalarFnArray(Cast, ...)`.
68#[derive(Default, Debug)]
69pub struct CastExecuteAdaptor<V>(pub V);
70
71impl<V> ExecuteParentKernel<V> for CastExecuteAdaptor<V>
72where
73    V: CastKernel,
74{
75    type Parent = ExactScalarFn<Cast>;
76
77    fn execute_parent(
78        &self,
79        array: &V::Array,
80        parent: <Self::Parent as Matcher>::Match<'_>,
81        _child_idx: usize,
82        ctx: &mut ExecutionCtx,
83    ) -> VortexResult<Option<ArrayRef>> {
84        let dtype = parent.options;
85        if array.dtype() == dtype {
86            return Ok(Some(array.clone().into_array()));
87        }
88        <V as CastKernel>::cast(array, dtype, ctx)
89    }
90}
vortex_array/scalar_fn/fns/cast/kernel.rs

vortex_array/scalar_fn/fns/cast/
kernel.rs
