tustvold commented on code in PR #4393: URL: https://github.com/apache/arrow-rs/pull/4393#discussion_r1248076603
########## arrow-array/src/scalar.rs: ########## @@ -0,0 +1,116 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use crate::Array; + +/// A possibly [`Scalar`] [`Array`] +/// +/// This allows optimised binary kernels where one or more arguments are constant +/// +/// ``` +/// # use arrow_array::*; +/// # use arrow_buffer::{BooleanBuffer, MutableBuffer, NullBuffer}; +/// # use arrow_schema::ArrowError; +/// # +/// fn eq_impl<T: ArrowPrimitiveType>( +/// a: &PrimitiveArray<T>, +/// a_scalar: bool, +/// b: &PrimitiveArray<T>, +/// b_scalar: bool, +/// ) -> BooleanArray { +/// let (array, scalar) = match (a_scalar, b_scalar) { +/// (true, true) | (false, false) => { +/// let len = a.len().min(b.len()); +/// let nulls = NullBuffer::union(a.nulls(), b.nulls()); +/// let buffer = BooleanBuffer::collect_bool(len, |idx| a.value(idx) == b.value(idx)); +/// return BooleanArray::new(buffer, nulls); +/// } +/// (true, false) => (b, (a.null_count() == 0).then(|| a.value(0))), +/// (false, true) => (a, (b.null_count() == 0).then(|| b.value(0))), +/// }; +/// match scalar { +/// Some(v) => { +/// let len = array.len(); +/// let nulls = array.nulls().cloned(); +/// let buffer = BooleanBuffer::collect_bool(len, |idx| array.value(idx) == v); +/// BooleanArray::new(buffer, nulls) +/// } +/// None => BooleanArray::new_null(array.len()), +/// } +/// } +/// +/// pub fn eq(l: &dyn Datum, r: &dyn Datum) -> Result<BooleanArray, ArrowError> { +/// let (l_array, l_scalar) = l.get(); +/// let (r_array, r_scalar) = r.get(); +/// downcast_primitive_array!( +/// (l_array, r_array) => Ok(eq_impl(l_array, l_scalar, r_array, r_scalar)), +/// (a, b) => Err(ArrowError::NotYetImplemented(format!("{a} == {b}"))), +/// ) +/// } +/// +/// // Comparison of two arrays +/// let a = Int32Array::from(vec![1, 2, 3, 4, 5]); +/// let b = Int32Array::from(vec![1, 2, 4, 7, 3]); +/// let r = eq(&a, &b).unwrap(); +/// let values: Vec<_> = r.values().iter().collect(); +/// assert_eq!(values, &[true, true, false, false, false]); +/// +/// // Comparison of an array and a scalar +/// let a = Int32Array::from(vec![1, 2, 3, 4, 5]); +/// let b = Int32Array::from(vec![1]); +/// let r = eq(&a, &Scalar::new(&b)).unwrap(); +/// let values: Vec<_> = r.values().iter().collect(); +/// assert_eq!(values, &[true, false, false, false, false]); +pub trait Datum { + /// Returns the value for this [`Datum`] and a boolean indicating if the value is scalar + fn get(&self) -> (&dyn Array, bool); +} + +impl<T: Array> Datum for T { + fn get(&self) -> (&dyn Array, bool) { + (self, false) + } +} Review Comment: https://github.com/apache/arrow-rs/pull/4393/files#diff-7174f433d1c74c0e47944054399558364f11d0a813e787b854196467fc7d7f8bR114 ? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
