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Merged
tustvold merged 5 commits into from
Aug 25, 2023
Merged

Cleanup length and bit_length kernels #4718

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Cleanup length and bit_length kernels
tustvold Aug 21, 2023
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Merge remote-tracking branch 'upstream/master' into cleanup-bit-lengt…
tustvold Aug 21, 2023
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Clippy
tustvold Aug 21, 2023
fb0e41c
Merge remote-tracking branch 'upstream/master' into cleanup-bit-lengt…
tustvold Aug 25, 2023
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tustvold Aug 25, 2023
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286 changes: 100 additions & 186 deletions arrow-string/src/length.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,139 +16,32 @@
// under the License.

//! Defines kernel for length of string arrays and binary arrays
#![allow(clippy::redundant_closure_call)]

use arrow_array::*;
use arrow_array::{cast::AsArray, types::*};
use arrow_buffer::Buffer;
use arrow_data::ArrayData;
use arrow_buffer::{ArrowNativeType, NullBuffer, OffsetBuffer};
use arrow_schema::{ArrowError, DataType};
use std::sync::Arc;

macro_rules! unary_offsets {
($array: expr, $data_type: expr, $op: expr) => {{
let slice = $array.value_offsets();

let lengths = slice.windows(2).map(|offset| $op(offset[1] - offset[0]));

// JUSTIFICATION
// Benefit
// ~60% speedup
// Soundness
// `values` come from a slice iterator with a known size.
let buffer = unsafe { Buffer::from_trusted_len_iter(lengths) };

let null_bit_buffer = $array.nulls().map(|b| b.inner().sliced());

let data = unsafe {
ArrayData::new_unchecked(
$data_type,
$array.len(),
None,
null_bit_buffer,
0,
vec![buffer],
vec![],
)
};
make_array(data)
}};
fn length_impl<P: ArrowPrimitiveType>(
offsets: &OffsetBuffer<P::Native>,
nulls: Option<&NullBuffer>,
) -> ArrayRef {
let v: Vec<_> = offsets
.windows(2)
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@alamb alamb Aug 23, 2023

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this is very clever 👍

.map(|w| w[1].sub_wrapping(w[0]))
.collect();
Arc::new(PrimitiveArray::<P>::new(v.into(), nulls.cloned()))
}

macro_rules! kernel_dict {
($array: ident, $kernel: expr, $kt: ident, $($t: ident: $gt: ident), *) => {
match $kt.as_ref() {
$(&DataType::$t => {
let dict = $array
.as_any()
.downcast_ref::<DictionaryArray<$gt>>()
.unwrap_or_else(|| {
panic!("Expect 'DictionaryArray<{}>' but got array of data type {:?}",
stringify!($gt), $array.data_type())
});
let values = $kernel(dict.values())?;
let result = DictionaryArray::try_new(dict.keys().clone(), values)?;
Ok(Arc::new(result))
},
)*
t => panic!("Unsupported dictionary key type: {}", t)
}
}
}

fn length_list<O, T>(array: &dyn Array) -> ArrayRef
where
O: OffsetSizeTrait,
T: ArrowPrimitiveType,
T::Native: OffsetSizeTrait,
{
let array = array
.as_any()
.downcast_ref::<GenericListArray<O>>()
.unwrap();
unary_offsets!(array, T::DATA_TYPE, |x| x)
}

fn length_list_fixed_size(array: &dyn Array, length: i32) -> ArrayRef {
let array = array.as_fixed_size_list();
let length_list = array.len();
let buffer = Buffer::from_vec(vec![length; length_list]);
let data = Int32Array::new(buffer.into(), array.nulls().cloned());
Arc::new(data)
}

fn length_binary<O, T>(array: &dyn Array) -> ArrayRef
where
O: OffsetSizeTrait,
T: ArrowPrimitiveType,
T::Native: OffsetSizeTrait,
{
let array = array
.as_any()
.downcast_ref::<GenericBinaryArray<O>>()
.unwrap();
unary_offsets!(array, T::DATA_TYPE, |x| x)
}

fn length_string<O, T>(array: &dyn Array) -> ArrayRef
where
O: OffsetSizeTrait,
T: ArrowPrimitiveType,
T::Native: OffsetSizeTrait,
{
let array = array
.as_any()
.downcast_ref::<GenericStringArray<O>>()
.unwrap();
unary_offsets!(array, T::DATA_TYPE, |x| x)
}

fn bit_length_binary<O, T>(array: &dyn Array) -> ArrayRef
where
O: OffsetSizeTrait,
T: ArrowPrimitiveType,
T::Native: OffsetSizeTrait,
{
let array = array
.as_any()
.downcast_ref::<GenericBinaryArray<O>>()
.unwrap();
let bits_in_bytes = O::from_usize(8).unwrap();
unary_offsets!(array, T::DATA_TYPE, |x| x * bits_in_bytes)
}

fn bit_length_string<O, T>(array: &dyn Array) -> ArrayRef
where
O: OffsetSizeTrait,
T: ArrowPrimitiveType,
T::Native: OffsetSizeTrait,
{
let array = array
.as_any()
.downcast_ref::<GenericStringArray<O>>()
.unwrap();
let bits_in_bytes = O::from_usize(8).unwrap();
unary_offsets!(array, T::DATA_TYPE, |x| x * bits_in_bytes)
fn bit_length_impl<P: ArrowPrimitiveType>(
offsets: &OffsetBuffer<P::Native>,
nulls: Option<&NullBuffer>,
) -> ArrayRef {
let bits = P::Native::usize_as(8);
let c = |w: &[P::Native]| w[1].sub_wrapping(w[0]).mul_wrapping(bits);
let v: Vec<_> = offsets.windows(2).map(c).collect();
Arc::new(PrimitiveArray::<P>::new(v.into(), nulls.cloned()))
}

/// Returns an array of Int32/Int64 denoting the length of each value in the array.
Expand All @@ -159,29 +52,39 @@ where
/// or DictionaryArray with above Arrays as values
/// * length of null is null.
pub fn length(array: &dyn Array) -> Result<ArrayRef, ArrowError> {
if let Some(d) = array.as_any_dictionary_opt() {
let lengths = length(d.values().as_ref())?;
return Ok(d.with_values(lengths));
}

match array.data_type() {
DataType::Dictionary(kt, _) => {
kernel_dict!(
array,
|a| { length(a) },
kt,
Int8: Int8Type,
Int16: Int16Type,
Int32: Int32Type,
Int64: Int64Type,
UInt8: UInt8Type,
UInt16: UInt16Type,
UInt32: UInt32Type,
UInt64: UInt64Type
)
DataType::List(_) => {
let list = array.as_list::<i32>();
Ok(length_impl::<Int32Type>(list.offsets(), list.nulls()))
}
DataType::LargeList(_) => {
let list = array.as_list::<i64>();
Ok(length_impl::<Int64Type>(list.offsets(), list.nulls()))
}
DataType::Utf8 => {
let list = array.as_string::<i32>();
Ok(length_impl::<Int32Type>(list.offsets(), list.nulls()))
}
DataType::LargeUtf8 => {
let list = array.as_string::<i64>();
Ok(length_impl::<Int64Type>(list.offsets(), list.nulls()))
}
DataType::List(_) => Ok(length_list::<i32, Int32Type>(array)),
DataType::LargeList(_) => Ok(length_list::<i64, Int64Type>(array)),
DataType::Utf8 => Ok(length_string::<i32, Int32Type>(array)),
DataType::LargeUtf8 => Ok(length_string::<i64, Int64Type>(array)),
DataType::Binary => Ok(length_binary::<i32, Int32Type>(array)),
DataType::LargeBinary => Ok(length_binary::<i64, Int64Type>(array)),
DataType::FixedSizeList(_, len) => Ok(length_list_fixed_size(array, *len)),
DataType::Binary => {
let list = array.as_binary::<i32>();
Ok(length_impl::<Int32Type>(list.offsets(), list.nulls()))
}
DataType::LargeBinary => {
let list = array.as_binary::<i64>();
Ok(length_impl::<Int64Type>(list.offsets(), list.nulls()))
}
DataType::FixedSizeBinary(len) | DataType::FixedSizeList(_, len) => Ok(Arc::new(
Int32Array::new(vec![*len; array.len()].into(), array.nulls().cloned()),
)),
other => Err(ArrowError::ComputeError(format!(
"length not supported for {other:?}"
))),
Expand All @@ -195,26 +98,40 @@ pub fn length(array: &dyn Array) -> Result<ArrayRef, ArrowError> {
/// * bit_length of null is null.
/// * bit_length is in number of bits
pub fn bit_length(array: &dyn Array) -> Result<ArrayRef, ArrowError> {
if let Some(d) = array.as_any_dictionary_opt() {
let lengths = bit_length(d.values().as_ref())?;
return Ok(d.with_values(lengths));
}

match array.data_type() {
DataType::Dictionary(kt, _) => {
kernel_dict!(
array,
|a| { bit_length(a) },
kt,
Int8: Int8Type,
Int16: Int16Type,
Int32: Int32Type,
Int64: Int64Type,
UInt8: UInt8Type,
UInt16: UInt16Type,
UInt32: UInt32Type,
UInt64: UInt64Type
)
DataType::List(_) => {
let list = array.as_list::<i32>();
Ok(bit_length_impl::<Int32Type>(list.offsets(), list.nulls()))
}
DataType::LargeList(_) => {
let list = array.as_list::<i64>();
Ok(bit_length_impl::<Int64Type>(list.offsets(), list.nulls()))
}
DataType::Utf8 => {
let list = array.as_string::<i32>();
Ok(bit_length_impl::<Int32Type>(list.offsets(), list.nulls()))
}
DataType::LargeUtf8 => {
let list = array.as_string::<i64>();
Ok(bit_length_impl::<Int64Type>(list.offsets(), list.nulls()))
}
DataType::Binary => {
let list = array.as_binary::<i32>();
Ok(bit_length_impl::<Int32Type>(list.offsets(), list.nulls()))
}
DataType::LargeBinary => {
let list = array.as_binary::<i64>();
Ok(bit_length_impl::<Int64Type>(list.offsets(), list.nulls()))
}
DataType::Utf8 => Ok(bit_length_string::<i32, Int32Type>(array)),
DataType::LargeUtf8 => Ok(bit_length_string::<i64, Int64Type>(array)),
DataType::Binary => Ok(bit_length_binary::<i32, Int32Type>(array)),
DataType::LargeBinary => Ok(bit_length_binary::<i64, Int64Type>(array)),
DataType::FixedSizeBinary(len) => Ok(Arc::new(Int32Array::new(
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@alamb alamb Aug 23, 2023

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the support for FixedSizeBinary seems to be new here but there is no test update -- maybe we can add a test for it?

vec![*len * 8; array.len()].into(),
array.nulls().cloned(),
))),
other => Err(ArrowError::ComputeError(format!(
"bit_length not supported for {other:?}"
))),
Expand All @@ -225,21 +142,15 @@ pub fn bit_length(array: &dyn Array) -> Result<ArrayRef, ArrowError> {
mod tests {
use super::*;
use arrow_array::cast::AsArray;
use arrow_buffer::NullBuffer;
use arrow_buffer::{Buffer, NullBuffer};
use arrow_data::ArrayData;
use arrow_schema::Field;

fn double_vec<T: Clone>(v: Vec<T>) -> Vec<T> {
[&v[..], &v[..]].concat()
}

fn length_cases_string() -> Vec<(Vec<&'static str>, usize, Vec<i32>)> {
// a large array
let mut values = vec!["one", "on", "o", ""];
let mut expected = vec![3, 2, 1, 0];
for _ in 0..10 {
values = double_vec(values);
expected = double_vec(expected);
}
let values = ["one", "on", "o", ""];
let values = values.into_iter().cycle().take(4096).collect();
let expected = [3, 2, 1, 0].into_iter().cycle().take(4096).collect();

vec![
(vec!["hello", " ", "world"], 3, vec![5, 1, 5]),
Expand Down Expand Up @@ -273,7 +184,6 @@ mod tests {
}

#[test]
#[cfg_attr(miri, ignore)] // running forever
fn length_test_string() {
length_cases_string()
.into_iter()
Expand All @@ -289,7 +199,6 @@ mod tests {
}

#[test]
#[cfg_attr(miri, ignore)] // running forever
fn length_test_large_string() {
length_cases_string()
.into_iter()
Expand Down Expand Up @@ -460,12 +369,9 @@ mod tests {

fn bit_length_cases() -> Vec<(Vec<&'static str>, usize, Vec<i32>)> {
// a large array
let mut values = vec!["one", "on", "o", ""];
let mut expected = vec![24, 16, 8, 0];
for _ in 0..10 {
values = double_vec(values);
expected = double_vec(expected);
}
let values = ["one", "on", "o", ""];
let values = values.into_iter().cycle().take(4096).collect();
let expected = [24, 16, 8, 0].into_iter().cycle().take(4096).collect();

vec![
(vec!["hello", " ", "world", "!"], 4, vec![40, 8, 40, 8]),
Expand All @@ -476,7 +382,6 @@ mod tests {
}

#[test]
#[cfg_attr(miri, ignore)] // error: this test uses too much memory to run on CI
fn bit_length_test_string() {
bit_length_cases()
.into_iter()
Expand All @@ -492,7 +397,6 @@ mod tests {
}

#[test]
#[cfg_attr(miri, ignore)] // error: this test uses too much memory to run on CI
fn bit_length_test_large_string() {
bit_length_cases()
.into_iter()
Expand Down Expand Up @@ -731,11 +635,21 @@ mod tests {
let list_array = FixedSizeListArray::from(list_data);

let lengths = length(&list_array).unwrap();
let lengths = lengths.as_any().downcast_ref::<Int32Array>().unwrap();
let lengths = lengths.as_primitive::<Int32Type>();

assert_eq!(lengths.len(), 3);
assert_eq!(lengths.value(0), 3);
assert!(lengths.is_null(1));
assert_eq!(lengths.value(2), 3);
}

#[test]
fn test_fixed_size_binary() {
let array = FixedSizeBinaryArray::new(4, [0; 16].into(), None);
let result = length(&array).unwrap();
assert_eq!(result.as_ref(), &Int32Array::from(vec![4; 4]));

let result = bit_length(&array).unwrap();
assert_eq!(result.as_ref(), &Int32Array::from(vec![32; 4]));
}
}