tustvold commented on code in PR #3783: URL: https://github.com/apache/arrow-rs/pull/3783#discussion_r1122093470
########## arrow-data/src/data/buffers.rs: ########## @@ -0,0 +1,97 @@ +// 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 arrow_buffer::Buffer; +use std::iter::Chain; +use std::ops::Index; + +/// A collection of [`Buffer`] +#[derive(Debug, Default, Copy, Clone, Eq, PartialEq)] +pub struct Buffers<'a>([Option<&'a Buffer>; 2]); + +impl<'a> Buffers<'a> { + /// Temporary will be removed once ArrayData does not store `Vec<Buffer>` directly (#3769) + #[inline] + pub(crate) fn from_slice(a: &'a [Buffer]) -> Self { + match a.len() { + 0 => Self([None, None]), + 1 => Self([Some(&a[0]), None]), + _ => Self([Some(&a[0]), Some(&a[1])]), + } + } + + /// Returns the number of [`Buffer`] in this collection + #[inline] + pub fn len(&self) -> usize { + self.0[0].is_some() as usize + self.0[1].is_some() as usize + } + + /// Returns `true` if this collection is empty + #[inline] + pub fn is_empty(&self) -> bool { + self.0[0].is_none() && self.0[1].is_none() + } + + #[inline] + pub fn iter(&self) -> IntoIter<'a> { + self.into_iter() + } + + /// Converts this [`Buffers`] to a `Vec<Buffer>` + #[inline] + pub fn to_vec(&self) -> Vec<Buffer> { + self.iter().cloned().collect() + } +} + +impl<'a> Index<usize> for Buffers<'a> { + type Output = &'a Buffer; + + #[inline] + fn index(&self, index: usize) -> &Self::Output { Review Comment: This is somewhat unfortunate, having to return `&&Buffer` but we need to return a borrow with a `'a` lifetime otherwise the following code doesn't compile. ``` let buffer = array.data().buffers()[0]; ``` -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
