Jefffrey commented on code in PR #17013: URL: https://github.com/apache/datafusion/pull/17013#discussion_r2347125367
########## datafusion/spark/src/function/bitwise/bit_shift.rs: ########## @@ -0,0 +1,747 @@ +// 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 std::any::Any; +use std::sync::Arc; + +use arrow::array::{ArrayRef, ArrowPrimitiveType, AsArray, PrimitiveArray}; +use arrow::compute; +use arrow::datatypes::{ + ArrowNativeType, DataType, Int32Type, Int64Type, UInt32Type, UInt64Type, +}; +use datafusion_common::{plan_err, Result}; +use datafusion_expr::{ + ColumnarValue, ScalarFunctionArgs, ScalarUDFImpl, Signature, Volatility, +}; +use datafusion_functions::utils::make_scalar_function; + +use crate::function::error_utils::{ + invalid_arg_count_exec_err, unsupported_data_type_exec_err, +}; + +/// Performs a bitwise left shift on each element of the `value` array by the corresponding amount in the `shift` array. +/// The shift amount is normalized to the bit width of the type, matching Spark/Java semantics for negative and large shifts. +/// +/// # Arguments +/// * `value` - The array of values to shift. +/// * `shift` - The array of shift amounts (must be Int32). +/// +/// # Returns +/// A new array with the shifted values. +/// Review Comment: ```suggestion ``` Would prefer to minimize verbosity of documentation where possible (applicable for the other similar instances below) ########## datafusion/spark/src/function/bitwise/bit_shift.rs: ########## @@ -0,0 +1,747 @@ +// 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 std::any::Any; +use std::sync::Arc; + +use arrow::array::{ArrayRef, ArrowPrimitiveType, AsArray, PrimitiveArray}; +use arrow::compute; +use arrow::datatypes::{ + ArrowNativeType, DataType, Int32Type, Int64Type, UInt32Type, UInt64Type, +}; +use datafusion_common::{plan_err, Result}; +use datafusion_expr::{ + ColumnarValue, ScalarFunctionArgs, ScalarUDFImpl, Signature, Volatility, +}; +use datafusion_functions::utils::make_scalar_function; + +use crate::function::error_utils::{ + invalid_arg_count_exec_err, unsupported_data_type_exec_err, +}; + +/// Performs a bitwise left shift on each element of the `value` array by the corresponding amount in the `shift` array. +/// The shift amount is normalized to the bit width of the type, matching Spark/Java semantics for negative and large shifts. +/// +/// # Arguments +/// * `value` - The array of values to shift. +/// * `shift` - The array of shift amounts (must be Int32). +/// +/// # Returns +/// A new array with the shifted values. +/// +fn shift_left<T: ArrowPrimitiveType>( + value: &PrimitiveArray<T>, + shift: &PrimitiveArray<Int32Type>, +) -> Result<PrimitiveArray<T>> +where + T::Native: ArrowNativeType + std::ops::Shl<i32, Output = T::Native>, +{ + let bit_num = (T::Native::get_byte_width() * 8) as i32; + let result = compute::binary::<_, Int32Type, _, _>( + value, + shift, + |value: T::Native, shift: i32| { + let shift = ((shift % bit_num) + bit_num) % bit_num; + value << shift + }, + )?; + Ok(result) +} + +/// Performs a bitwise right shift on each element of the `value` array by the corresponding amount in the `shift` array. +/// The shift amount is normalized to the bit width of the type, matching Spark/Java semantics for negative and large shifts. +/// +/// # Arguments +/// * `value` - The array of values to shift. +/// * `shift` - The array of shift amounts (must be Int32). +/// +/// # Returns +/// A new array with the shifted values. +/// +fn shift_right<T: ArrowPrimitiveType>( + value: &PrimitiveArray<T>, + shift: &PrimitiveArray<Int32Type>, +) -> Result<PrimitiveArray<T>> +where + T::Native: ArrowNativeType + std::ops::Shr<i32, Output = T::Native>, +{ + let bit_num = (T::Native::get_byte_width() * 8) as i32; + let result = compute::binary::<_, Int32Type, _, _>( + value, + shift, + |value: T::Native, shift: i32| { + let shift = ((shift % bit_num) + bit_num) % bit_num; + value >> shift + }, + )?; + Ok(result) +} + +/// Trait for performing an unsigned right shift (logical shift right). +/// This is used to mimic Java's `>>>` operator, which does not exist in Rust. +/// For unsigned types, this is just the normal right shift. +/// For signed types, this casts to the unsigned type, shifts, then casts back. +pub trait UShr<Rhs = Self> { + type Output; + + #[must_use] + fn ushr(self, rhs: Rhs) -> Self::Output; +} Review Comment: ```suggestion trait UShr<Rhs> { fn ushr(self, rhs: Rhs) -> Self; } ``` Some simplifications - Since Rhs is always specified, no point having default - Output type is always same as Self in implementations so can remove that - Don't think must_use attribute is necessary here -- This is an automated message from the Apache Git Service. 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