alamb commented on code in PR #7772: URL: https://github.com/apache/arrow-rs/pull/7772#discussion_r2166538367
########## arrow-select/src/coalesce/primitive.rs: ########## @@ -0,0 +1,101 @@ +// 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::coalesce::InProgressArray; +use arrow_array::cast::AsArray; +use arrow_array::{Array, ArrayRef, ArrowPrimitiveType, PrimitiveArray}; +use arrow_buffer::{NullBufferBuilder, ScalarBuffer}; +use arrow_schema::ArrowError; +use std::fmt::Debug; +use std::sync::Arc; + +/// InProgressArray for [`PrimitiveArray`] +#[derive(Debug)] +pub(crate) struct InProgressPrimitiveArray<T: ArrowPrimitiveType> { + /// The current source, if any + source: Option<ArrayRef>, + /// the target batch size (and thus size for views allocation) + batch_size: usize, + /// In progress nulls + nulls: NullBufferBuilder, + /// The currently in progress array + current: Vec<T::Native>, +} + +impl<T: ArrowPrimitiveType> InProgressPrimitiveArray<T> { + /// Create a new `InProgressPrimitiveArray` + pub(crate) fn new(batch_size: usize) -> Self { + Self { + batch_size, + source: None, + nulls: NullBufferBuilder::new(batch_size), + current: vec![], + } + } + + /// Allocate space for output values if necessary. + /// + /// This is done on write (when we know it is necessary) rather than + /// eagerly to avoid allocations that are not used. + fn ensure_capacity(&mut self) { + self.current.reserve(self.batch_size); + } +} + +impl<T: ArrowPrimitiveType + Debug> InProgressArray for InProgressPrimitiveArray<T> { + fn set_source(&mut self, source: Option<ArrayRef>) { + self.source = source; + } + + fn copy_rows(&mut self, offset: usize, len: usize) -> Result<(), ArrowError> { + self.ensure_capacity(); + + let s = self + .source + .as_ref() + .ok_or_else(|| { + ArrowError::InvalidArgumentError( + "Internal Error: InProgressPrimitiveArray: source not set".to_string(), + ) + })? + .as_primitive::<T>(); + + // add nulls if necessary + if let Some(nulls) = s.nulls().as_ref() { + let nulls = nulls.slice(offset, len); + self.nulls.append_buffer(&nulls); + } else { + self.nulls.append_n_non_nulls(len); + }; + + // Copy the values + self.current + .extend_from_slice(&s.values()[offset..offset + len]); Review Comment: this is the meat of this PR: copy the values into the final destination incrementally -- 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
