askoa commented on code in PR #3553: URL: https://github.com/apache/arrow-rs/pull/3553#discussion_r1083961856
########## arrow-array/src/builder/generic_byte_ree_array_builder.rs: ########## @@ -0,0 +1,423 @@ +// 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::{ + types::{ + ArrowRunEndIndexType, BinaryType, ByteArrayType, LargeBinaryType, LargeUtf8Type, + Utf8Type, + }, + ArrowPrimitiveType, RunEndEncodedArray, +}; + +use super::{GenericByteBuilder, PrimitiveBuilder}; + +use arrow_buffer::ArrowNativeType; +use arrow_schema::ArrowError; + +/// Array builder for [`RunEndEncodedArray`] for String and Binary types. +/// +/// # Example: +/// +/// ``` +/// +/// # use arrow_array::builder::GenericByteREEArrayBuilder; +/// # use arrow_array::{GenericByteArray, BinaryArray}; +/// # use arrow_array::types::{BinaryType, Int16Type}; +/// # use arrow_array::{Array, Int16Array}; +/// +/// let mut builder = +/// GenericByteREEArrayBuilder::<Int16Type, BinaryType>::new(); +/// builder.append_value(b"abc").unwrap(); +/// builder.append_value(b"abc").unwrap(); +/// builder.append_null().unwrap(); +/// builder.append_value(b"def").unwrap(); +/// let array = builder.finish(); +/// +/// assert_eq!( +/// array.run_ends(), +/// &Int16Array::from(vec![Some(2), Some(3), Some(4)]) +/// ); +/// +/// let av = array.values(); +/// +/// assert!(!av.is_null(0)); +/// assert!(av.is_null(1)); +/// assert!(!av.is_null(2)); +/// +/// // Values are polymorphic and so require a downcast. +/// let ava: &BinaryArray = av.as_any().downcast_ref::<BinaryArray>().unwrap(); +/// +/// assert_eq!(ava.value(0), b"abc"); +/// assert_eq!(ava.value(2), b"def"); +/// ``` +#[derive(Debug)] +pub struct GenericByteREEArrayBuilder<R, V> +where + R: ArrowPrimitiveType, + V: ByteArrayType, +{ + run_ends_builder: PrimitiveBuilder<R>, + values_builder: GenericByteBuilder<V>, + current_value: Option<Vec<u8>>, + current_run_end_index: usize, +} + +impl<R, V> Default for GenericByteREEArrayBuilder<R, V> +where + R: ArrowPrimitiveType, + V: ByteArrayType, +{ + fn default() -> Self { + Self::new() + } +} + +impl<R, V> GenericByteREEArrayBuilder<R, V> +where + R: ArrowPrimitiveType, + V: ByteArrayType, +{ + /// Creates a new `GenericByteREEArrayBuilder` + pub fn new() -> Self { + Self { + run_ends_builder: PrimitiveBuilder::new(), + values_builder: GenericByteBuilder::<V>::new(), + current_value: None, + current_run_end_index: 0, + } + } + + /// Creates a new `GenericByteREEArrayBuilder` with the provided capacity + /// + /// `capacity`: the expected number of run-end encoded values. + /// `data_capacity`: the expected number of bytes of run end encoded values + pub fn with_capacity(capacity: usize, data_capacity: usize) -> Self { + Self { + run_ends_builder: PrimitiveBuilder::with_capacity(capacity), + values_builder: GenericByteBuilder::<V>::with_capacity( + capacity, + data_capacity, + ), + current_value: None, + current_run_end_index: 0, + } + } +} + +impl<R, V> GenericByteREEArrayBuilder<R, V> +where + R: ArrowRunEndIndexType, + V: ByteArrayType, +{ + /// Appends optional value to the logical array encoded by the RunEndEncodedArray. + pub fn append_option( + &mut self, + input_value: Option<impl AsRef<V::Native>>, + ) -> Result<(), ArrowError> { + match input_value { + Some(value) => self.append_value(value)?, + None => self.append_null()?, + } + Ok(()) + } + + /// Appends value to the logical array encoded by the RunEndEncodedArray. + pub fn append_value( + &mut self, + input_value: impl AsRef<V::Native>, + ) -> Result<(), ArrowError> { + let value: &[u8] = input_value.as_ref().as_ref(); + match self.current_value.as_deref() { + None if self.current_run_end_index > 0 => { + self.append_run_end()?; + self.current_value = Some(value.to_owned()); + } + None if self.current_run_end_index == 0 => { + self.current_value = Some(value.to_owned()); + } + Some(current_value) if current_value != value => { + self.append_run_end()?; + self.current_value = Some(value.to_owned()); + } + _ => {} + } + self.current_run_end_index = self + .current_run_end_index + .checked_add(1) + .ok_or(ArrowError::RunEndIndexOverflowError)?; + Ok(()) + } + + /// Appends null to the logical array encoded by the RunEndEncodedArray. + pub fn append_null(&mut self) -> Result<(), ArrowError> { + if self.current_value.is_some() { + self.append_run_end()?; + self.current_value = None; + } + self.current_run_end_index = self + .current_run_end_index + .checked_add(1) + .ok_or(ArrowError::RunEndIndexOverflowError)?; + Ok(()) + } + + /// Creates the RunEndEncodedArray and resets the builder. + /// Panics if RunEndEncodedArray cannot be built. + pub fn finish(&mut self) -> RunEndEncodedArray<R> { + // write the last run end to the array. + self.append_run_end().unwrap(); + + // reset the run end index to zero. + self.current_value = None; + self.current_run_end_index = 0; + + // build the run encoded array by adding run_ends and values array as its children. + let run_ends_array = self.run_ends_builder.finish(); + let values_array = self.values_builder.finish(); + RunEndEncodedArray::<R>::try_new(&run_ends_array, &values_array).unwrap() + } + + /// Creates the RunEndEncodedArray and without resetting the builder. + /// Panics if RunEndEncodedArray cannot be built. + pub fn finish_cloned(&mut self) -> RunEndEncodedArray<R> { + // write the last run end to the array. + self.append_run_end().unwrap(); + + // build the run encoded array by adding run_ends and values array as its children. + let run_ends_array = self.run_ends_builder.finish_cloned(); + let values_array = self.values_builder.finish_cloned(); + RunEndEncodedArray::<R>::try_new(&run_ends_array, &values_array).unwrap() + } + + // Appends the current run to the array + fn append_run_end(&mut self) -> Result<(), ArrowError> { + let run_end_index = R::Native::from_usize(self.current_run_end_index) + .ok_or_else(|| { + ArrowError::ParseError(format!( + "Cannot convert the value {} from `usize` to native form of arrow datatype {}", + self.current_run_end_index, + R::DATA_TYPE + )) + })?; + self.run_ends_builder.append_value(run_end_index); + match self.current_value.as_deref() { + Some(value) => self.values_builder.append_slice(value), + None => self.values_builder.append_null(), + } + Ok(()) + } +} + +/// Array builder for [`RunEndEncodedArray`] that encodes strings ([`Utf8Type`]). +/// +/// ``` +/// // Create a run-end encoded array with run-end indexes data type as `i16`. +/// // The encoded values are Strings. +/// +/// # use arrow_array::builder::StringREEArrayBuilder; +/// # use arrow_array::{Int16Array, StringArray}; +/// # use arrow_array::types::Int16Type; +/// +/// let mut builder = StringREEArrayBuilder::<Int16Type>::new(); +/// +/// // The builder builds the dictionary value by value +/// builder.append_value("abc").unwrap(); +/// builder.append_null(); +/// builder.append_value("def").unwrap(); +/// builder.append_value("def").unwrap(); +/// builder.append_value("abc").unwrap(); +/// let array = builder.finish(); +/// +/// assert_eq!( +/// array.run_ends(), +/// &Int16Array::from(vec![Some(1), Some(2), Some(4), Some(5)]) +/// ); +/// +/// // Values are polymorphic and so require a downcast. +/// let av = array.values(); +/// let ava: &StringArray = av.as_any().downcast_ref::<StringArray>().unwrap(); +/// +/// assert_eq!(ava.value(0), "abc"); +/// assert!(av.is_null(1)); +/// assert_eq!(ava.value(2), "def"); +/// assert_eq!(ava.value(3), "abc"); +/// +/// ``` +pub type StringREEArrayBuilder<K> = GenericByteREEArrayBuilder<K, Utf8Type>; + +/// Array builder for [`RunEndEncodedArray`] that encodes large strings ([`LargeUtf8Type`]). See [`StringREEArrayBuilder`] for an example. +pub type LargeStringREEArrayBuilder<K> = GenericByteREEArrayBuilder<K, LargeUtf8Type>; + +/// Array builder for [`RunEndEncodedArray`] that encodes binary values([`BinaryType`]). +/// +/// ``` +/// // Create a run-end encoded array with run-end indexes data type as `i16`. +/// // The encoded data is binary values. +/// +/// # use arrow_array::builder::BinaryREEArrayBuilder; +/// # use arrow_array::{BinaryArray, Int16Array}; +/// # use arrow_array::types::Int16Type; +/// +/// let mut builder = BinaryREEArrayBuilder::<Int16Type>::new(); +/// +/// // The builder builds the dictionary value by value +/// builder.append_value(b"abc").unwrap(); +/// builder.append_null(); +/// builder.append_value(b"def").unwrap(); +/// builder.append_value(b"def").unwrap(); +/// builder.append_value(b"abc").unwrap(); +/// let array = builder.finish(); +/// +/// assert_eq!( +/// array.run_ends(), +/// &Int16Array::from(vec![Some(1), Some(2), Some(4), Some(5)]) +/// ); +/// +/// // Values are polymorphic and so require a downcast. +/// let av = array.values(); +/// let ava: &BinaryArray = av.as_any().downcast_ref::<BinaryArray>().unwrap(); +/// +/// assert_eq!(ava.value(0), b"abc"); +/// assert!(av.is_null(1)); +/// assert_eq!(ava.value(2), b"def"); +/// assert_eq!(ava.value(3), b"abc"); +/// +/// ``` +pub type BinaryREEArrayBuilder<K> = GenericByteREEArrayBuilder<K, BinaryType>; + +/// Array builder for [`RunEndEncodedArray`] that encodes large binary values([`LargeBinaryType`]). +/// See documentation of [`BinaryREEArrayBuilder`] for an example. +pub type LargeBinaryREEArrayBuilder<K> = GenericByteREEArrayBuilder<K, LargeBinaryType>; + +#[cfg(test)] +mod tests { + use super::*; + + use crate::array::Array; + use crate::types::Int16Type; + use crate::GenericByteArray; + use crate::Int16Array; + + fn test_bytes_ree_array_buider<T>(values: Vec<&T::Native>) Review Comment: I don't see why this should be changed. Keeping it as `Vec` helps adding more test cases in future with varying no of items. -- 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]
