jayzhan211 commented on code in PR #9720: URL: https://github.com/apache/arrow-datafusion/pull/9720#discussion_r1533492737
########## datafusion/functions-array/src/range.rs: ########## @@ -0,0 +1,332 @@ +// 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. + +//! [`ScalarUDFImpl`] definitions for range and gen_series functions. + +use arrow::array::{Array, ArrayRef, Int64Array, ListArray}; +use arrow::datatypes::{DataType, Field}; +use arrow_buffer::{BooleanBufferBuilder, NullBuffer, OffsetBuffer}; +use std::any::Any; + +use arrow_array::types::{Date32Type, IntervalMonthDayNanoType}; +use arrow_array::Date32Array; +use arrow_schema::IntervalUnit::MonthDayNano; +use datafusion_common::cast::{as_date32_array, as_int64_array, as_interval_mdn_array}; +use datafusion_common::{exec_err, not_impl_datafusion_err, Result}; +use datafusion_expr::expr::ScalarFunction; +use datafusion_expr::Expr; +use datafusion_expr::{ + ColumnarValue, ScalarUDFImpl, Signature, TypeSignature, Volatility, +}; +use std::sync::Arc; + +make_udf_function!( + Range, + range, + start stop step, + "create a list of values in the range between start and stop", + range_udf +); +#[derive(Debug)] +pub(super) struct Range { + signature: Signature, + aliases: Vec<String>, +} +impl Range { + pub fn new() -> Self { + use DataType::*; + Self { + signature: Signature::one_of( + vec![ + TypeSignature::Exact(vec![Int64]), + TypeSignature::Exact(vec![Int64, Int64]), + TypeSignature::Exact(vec![Int64, Int64, Int64]), + TypeSignature::Exact(vec![Date32, Date32, Interval(MonthDayNano)]), + ], + Volatility::Immutable, + ), + aliases: vec![String::from("range")], + } + } +} +impl ScalarUDFImpl for Range { + fn as_any(&self) -> &dyn Any { + self + } + fn name(&self) -> &str { + "range" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> { + use DataType::*; + Ok(List(Arc::new(Field::new( + "item", + arg_types[0].clone(), + true, + )))) + } + + fn invoke(&self, args: &[ColumnarValue]) -> Result<ColumnarValue> { + let args = ColumnarValue::values_to_arrays(args)?; + match args[0].data_type() { + DataType::Int64 => gen_range_inner(&args, false).map(ColumnarValue::Array), + DataType::Date32 => gen_range_date(&args, false).map(ColumnarValue::Array), + _ => { + exec_err!("unsupported type for range") + } + } + } + + fn aliases(&self) -> &[String] { + &self.aliases + } +} + +make_udf_function!( + GenSeries, + gen_series, + start stop step, + "create a list of values in the range between start and stop, include upper bound", + gen_series_udf +); +#[derive(Debug)] +pub(super) struct GenSeries { + signature: Signature, + aliases: Vec<String>, +} +impl GenSeries { + pub fn new() -> Self { + use DataType::*; + Self { + signature: Signature::one_of( + vec![ + TypeSignature::Exact(vec![Int64]), + TypeSignature::Exact(vec![Int64, Int64]), + TypeSignature::Exact(vec![Int64, Int64, Int64]), + TypeSignature::Exact(vec![Date32, Date32, Interval(MonthDayNano)]), + ], + Volatility::Immutable, + ), + aliases: vec![String::from("generate_series")], + } + } +} +impl ScalarUDFImpl for GenSeries { + fn as_any(&self) -> &dyn Any { + self + } + fn name(&self) -> &str { + "generate_series" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, arg_types: &[DataType]) -> Result<DataType> { + use DataType::*; + Ok(List(Arc::new(Field::new( + "item", + arg_types[0].clone(), + true, + )))) + } + + fn invoke(&self, args: &[ColumnarValue]) -> Result<ColumnarValue> { + let args = ColumnarValue::values_to_arrays(args)?; + match args[0].data_type() { + DataType::Int64 => gen_range_inner(&args, true).map(ColumnarValue::Array), + DataType::Date32 => gen_range_date(&args, true).map(ColumnarValue::Array), + _ => { + exec_err!("unsupported type for range") + } + } + } + + fn aliases(&self) -> &[String] { + &self.aliases + } +} + +/// Generates an array of integers from start to stop with a given step. +/// +/// This function takes 1 to 3 ArrayRefs as arguments, representing start, stop, and step values. +/// It returns a `Result<ArrayRef>` representing the resulting ListArray after the operation. +/// +/// # Arguments +/// +/// * `args` - An array of 1 to 3 ArrayRefs representing start, stop, and step(step value can not be zero.) values. +/// +/// # Examples +/// +/// gen_range(3) => [0, 1, 2] +/// gen_range(1, 4) => [1, 2, 3] +/// gen_range(1, 7, 2) => [1, 3, 5] +pub(super) fn gen_range_inner( + args: &[ArrayRef], + include_upper: bool, +) -> Result<ArrayRef> { + let (start_array, stop_array, step_array) = match args.len() { + 1 => (None, as_int64_array(&args[0])?, None), + 2 => ( + Some(as_int64_array(&args[0])?), + as_int64_array(&args[1])?, + None, + ), + 3 => ( + Some(as_int64_array(&args[0])?), + as_int64_array(&args[1])?, + Some(as_int64_array(&args[2])?), + ), + _ => return exec_err!("gen_range expects 1 to 3 arguments"), + }; + + let mut values = vec![]; + let mut offsets = vec![0]; + let mut valid = BooleanBufferBuilder::new(stop_array.len()); + for (idx, stop) in stop_array.iter().enumerate() { + match retrieve_range_args(start_array, stop, step_array, idx) { + Some((_, _, 0)) => { + return exec_err!( + "step can't be 0 for function {}(start [, stop, step])", + if include_upper { + "generate_series" + } else { + "range" + } + ); + } + Some((start, stop, step)) => { + // Below, we utilize `usize` to represent steps. + // On 32-bit targets, the absolute value of `i64` may fail to fit into `usize`. + let step_abs = usize::try_from(step.unsigned_abs()).map_err(|_| { + not_impl_datafusion_err!("step {} can't fit into usize", step) + })?; + values.extend( + gen_range_iter(start, stop, step < 0, include_upper) + .step_by(step_abs), + ); + offsets.push(values.len() as i32); + valid.append(true); + } + // If any of the arguments is NULL, append a NULL value to the result. + None => { + offsets.push(values.len() as i32); + valid.append(false); + } + }; + } + let arr = Arc::new(ListArray::try_new( + Arc::new(Field::new("item", DataType::Int64, true)), + OffsetBuffer::new(offsets.into()), + Arc::new(Int64Array::from(values)), + Some(NullBuffer::new(valid.finish())), + )?); + Ok(arr) +} + +/// Get the (start, stop, step) args for the range and generate_series function. +/// If any of the arguments is NULL, returns None. +fn retrieve_range_args( + start_array: Option<&Int64Array>, + stop: Option<i64>, + step_array: Option<&Int64Array>, + idx: usize, +) -> Option<(i64, i64, i64)> { + // Default start value is 0 if not provided + let start = + start_array.map_or(Some(0), |arr| arr.is_valid(idx).then(|| arr.value(idx)))?; + let stop = stop?; + // Default step value is 1 if not provided + let step = + step_array.map_or(Some(1), |arr| arr.is_valid(idx).then(|| arr.value(idx)))?; + Some((start, stop, step)) +} + +/// Returns an iterator of i64 values from start to stop +fn gen_range_iter( + start: i64, + stop: i64, + decreasing: bool, + include_upper: bool, +) -> Box<dyn Iterator<Item = i64>> { + match (decreasing, include_upper) { + // Decreasing range, stop is inclusive + (true, true) => Box::new((stop..=start).rev()), + // Decreasing range, stop is exclusive + (true, false) => { + if stop == i64::MAX { + // start is never greater than stop, and stop is exclusive, + // so the decreasing range must be empty. + Box::new(std::iter::empty()) + } else { + // Increase the stop value by one to exclude it. + // Since stop is not i64::MAX, `stop + 1` will not overflow. + Box::new((stop + 1..=start).rev()) + } + } + // Increasing range, stop is inclusive + (false, true) => Box::new(start..=stop), + // Increasing range, stop is exclusive + (false, false) => Box::new(start..stop), + } +} + +pub fn gen_range_date(args: &[ArrayRef], include_upper: bool) -> Result<ArrayRef> { Review Comment: I think it is private function -- 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]
