alamb commented on code in PR #8827: URL: https://github.com/apache/arrow-datafusion/pull/8827#discussion_r1485060991
########## datafusion/physical-expr/src/string_map.rs: ########## @@ -0,0 +1,1016 @@ +// 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. + +//! [`ArrowStringMap`] and [`ArrowStringSet`] for storing maps/sets of values from +//! StringArray / LargeStringArray + +use ahash::RandomState; +use arrow_array::cast::AsArray; +use arrow_array::{Array, ArrayRef, GenericStringArray, OffsetSizeTrait}; +use arrow_buffer::{ + BooleanBufferBuilder, BufferBuilder, NullBuffer, OffsetBuffer, ScalarBuffer, +}; +use datafusion_common::hash_utils::create_hashes; +use datafusion_execution::memory_pool::proxy::{RawTableAllocExt, VecAllocExt}; +use std::fmt::Debug; +use std::mem; +use std::ops::Range; +use std::sync::Arc; + +/// HashSet optimized for storing `String` and `LargeString` values +/// and producing the final set as a GenericStringArray with minimal copies. +#[derive(Debug, Default)] +pub struct ArrowStringSet<O: OffsetSizeTrait>(ArrowStringMap<O, ()>); + +impl<O: OffsetSizeTrait> ArrowStringSet<O> { + pub fn new() -> Self { + Self(ArrowStringMap::new()) + } + + /// Inserts each string from `values` into the set + pub fn insert(&mut self, values: &ArrayRef) { + fn make_payload_fn(_value: Option<&[u8]>) {} + fn observe_payload_fn(_payload: ()) {} + self.0 + .insert_if_new(values, make_payload_fn, observe_payload_fn); + } + + /// Converts this set into a `StringArray` or `LargeStringArray` containing each + /// distinct string value. This is done without copying the values. + pub fn into_state(self) -> ArrayRef { + self.0.into_state() + } + + /// Returns the total number of distinct strings (including nulls) seen so far + pub fn len(&self) -> usize { + self.0.len() + } + + pub fn is_empty(&self) -> bool { + self.0.is_empty() + } + + /// returns the total number of distinct strings (not including nulls) seen so far + pub fn non_null_len(&self) -> usize { + self.0.non_null_len() + } + + /// Return the total size, in bytes, of memory used to store the data in + /// this set, not including `self` + pub fn size(&self) -> usize { + self.0.size() + } +} + +/// Map optimized for storing `String` and `LargeString` values that can produce Review Comment: Here is the core new data structure -- a special HashMap of string keys --> values where the key input and output are string arrays. -- 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]
