datafusion_functions/strings.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424
// 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 std::mem::size_of;
use arrow::array::{
make_view, Array, ArrayAccessor, ArrayDataBuilder, ArrayIter, ByteView,
GenericStringArray, LargeStringArray, OffsetSizeTrait, StringArray, StringViewArray,
StringViewBuilder,
};
use arrow::datatypes::DataType;
use arrow_buffer::{MutableBuffer, NullBuffer, NullBufferBuilder};
/// Abstracts iteration over different types of string arrays.
///
/// The [`StringArrayType`] trait helps write generic code for string functions that can work with
/// different types of string arrays.
///
/// Currently three types are supported:
/// - [`StringArray`]
/// - [`LargeStringArray`]
/// - [`StringViewArray`]
///
/// It is inspired / copied from [arrow-rs].
///
/// [arrow-rs]: https://github.com/apache/arrow-rs/blob/bf0ea9129e617e4a3cf915a900b747cc5485315f/arrow-string/src/like.rs#L151-L157
///
/// # Examples
/// Generic function that works for [`StringArray`], [`LargeStringArray`]
/// and [`StringViewArray`]:
/// ```
/// # use arrow::array::{StringArray, LargeStringArray, StringViewArray};
/// # use datafusion_functions::strings::StringArrayType;
///
/// /// Combines string values for any StringArrayType type. It can be invoked on
/// /// and combination of `StringArray`, `LargeStringArray` or `StringViewArray`
/// fn combine_values<'a, S1, S2>(array1: S1, array2: S2) -> Vec<String>
/// where S1: StringArrayType<'a>, S2: StringArrayType<'a>
/// {
/// // iterate over the elements of the 2 arrays in parallel
/// array1
/// .iter()
/// .zip(array2.iter())
/// .map(|(s1, s2)| {
/// // if both values are non null, combine them
/// if let (Some(s1), Some(s2)) = (s1, s2) {
/// format!("{s1}{s2}")
/// } else {
/// "None".to_string()
/// }
/// })
/// .collect()
/// }
///
/// let string_array = StringArray::from(vec!["foo", "bar"]);
/// let large_string_array = LargeStringArray::from(vec!["foo2", "bar2"]);
/// let string_view_array = StringViewArray::from(vec!["foo3", "bar3"]);
///
/// // can invoke this function a string array and large string array
/// assert_eq!(
/// combine_values(&string_array, &large_string_array),
/// vec![String::from("foofoo2"), String::from("barbar2")]
/// );
///
/// // Can call the same function with string array and string view array
/// assert_eq!(
/// combine_values(&string_array, &string_view_array),
/// vec![String::from("foofoo3"), String::from("barbar3")]
/// );
/// ```
///
/// [`LargeStringArray`]: arrow::array::LargeStringArray
pub trait StringArrayType<'a>: ArrayAccessor<Item = &'a str> + Sized {
/// Return an [`ArrayIter`] over the values of the array.
///
/// This iterator iterates returns `Option<&str>` for each item in the array.
fn iter(&self) -> ArrayIter<Self>;
/// Check if the array is ASCII only.
fn is_ascii(&self) -> bool;
}
impl<'a, T: OffsetSizeTrait> StringArrayType<'a> for &'a GenericStringArray<T> {
fn iter(&self) -> ArrayIter<Self> {
GenericStringArray::<T>::iter(self)
}
fn is_ascii(&self) -> bool {
GenericStringArray::<T>::is_ascii(self)
}
}
impl<'a> StringArrayType<'a> for &'a StringViewArray {
fn iter(&self) -> ArrayIter<Self> {
StringViewArray::iter(self)
}
fn is_ascii(&self) -> bool {
StringViewArray::is_ascii(self)
}
}
/// Optimized version of the StringBuilder in Arrow that:
/// 1. Precalculating the expected length of the result, avoiding reallocations.
/// 2. Avoids creating / incrementally creating a `NullBufferBuilder`
pub struct StringArrayBuilder {
offsets_buffer: MutableBuffer,
value_buffer: MutableBuffer,
}
impl StringArrayBuilder {
pub fn with_capacity(item_capacity: usize, data_capacity: usize) -> Self {
let mut offsets_buffer =
MutableBuffer::with_capacity((item_capacity + 1) * size_of::<i32>());
// SAFETY: the first offset value is definitely not going to exceed the bounds.
unsafe { offsets_buffer.push_unchecked(0_i32) };
Self {
offsets_buffer,
value_buffer: MutableBuffer::with_capacity(data_capacity),
}
}
pub fn write<const CHECK_VALID: bool>(
&mut self,
column: &ColumnarValueRef,
i: usize,
) {
match column {
ColumnarValueRef::Scalar(s) => {
self.value_buffer.extend_from_slice(s);
}
ColumnarValueRef::NullableArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
ColumnarValueRef::NullableLargeStringArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
ColumnarValueRef::NullableStringViewArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
ColumnarValueRef::NonNullableArray(array) => {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
ColumnarValueRef::NonNullableLargeStringArray(array) => {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
ColumnarValueRef::NonNullableStringViewArray(array) => {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
}
pub fn append_offset(&mut self) {
let next_offset: i32 = self
.value_buffer
.len()
.try_into()
.expect("byte array offset overflow");
unsafe { self.offsets_buffer.push_unchecked(next_offset) };
}
pub fn finish(self, null_buffer: Option<NullBuffer>) -> StringArray {
let array_builder = ArrayDataBuilder::new(DataType::Utf8)
.len(self.offsets_buffer.len() / size_of::<i32>() - 1)
.add_buffer(self.offsets_buffer.into())
.add_buffer(self.value_buffer.into())
.nulls(null_buffer);
// SAFETY: all data that was appended was valid UTF8 and the values
// and offsets were created correctly
let array_data = unsafe { array_builder.build_unchecked() };
StringArray::from(array_data)
}
}
pub struct StringViewArrayBuilder {
builder: StringViewBuilder,
block: String,
}
impl StringViewArrayBuilder {
pub fn with_capacity(_item_capacity: usize, data_capacity: usize) -> Self {
let builder = StringViewBuilder::with_capacity(data_capacity);
Self {
builder,
block: String::new(),
}
}
pub fn write<const CHECK_VALID: bool>(
&mut self,
column: &ColumnarValueRef,
i: usize,
) {
match column {
ColumnarValueRef::Scalar(s) => {
self.block.push_str(std::str::from_utf8(s).unwrap());
}
ColumnarValueRef::NullableArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.block.push_str(
std::str::from_utf8(array.value(i).as_bytes()).unwrap(),
);
}
}
ColumnarValueRef::NullableLargeStringArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.block.push_str(
std::str::from_utf8(array.value(i).as_bytes()).unwrap(),
);
}
}
ColumnarValueRef::NullableStringViewArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.block.push_str(
std::str::from_utf8(array.value(i).as_bytes()).unwrap(),
);
}
}
ColumnarValueRef::NonNullableArray(array) => {
self.block
.push_str(std::str::from_utf8(array.value(i).as_bytes()).unwrap());
}
ColumnarValueRef::NonNullableLargeStringArray(array) => {
self.block
.push_str(std::str::from_utf8(array.value(i).as_bytes()).unwrap());
}
ColumnarValueRef::NonNullableStringViewArray(array) => {
self.block
.push_str(std::str::from_utf8(array.value(i).as_bytes()).unwrap());
}
}
}
pub fn append_offset(&mut self) {
self.builder.append_value(&self.block);
self.block = String::new();
}
pub fn finish(mut self) -> StringViewArray {
self.builder.finish()
}
}
pub struct LargeStringArrayBuilder {
offsets_buffer: MutableBuffer,
value_buffer: MutableBuffer,
}
impl LargeStringArrayBuilder {
pub fn with_capacity(item_capacity: usize, data_capacity: usize) -> Self {
let mut offsets_buffer =
MutableBuffer::with_capacity((item_capacity + 1) * size_of::<i64>());
// SAFETY: the first offset value is definitely not going to exceed the bounds.
unsafe { offsets_buffer.push_unchecked(0_i64) };
Self {
offsets_buffer,
value_buffer: MutableBuffer::with_capacity(data_capacity),
}
}
pub fn write<const CHECK_VALID: bool>(
&mut self,
column: &ColumnarValueRef,
i: usize,
) {
match column {
ColumnarValueRef::Scalar(s) => {
self.value_buffer.extend_from_slice(s);
}
ColumnarValueRef::NullableArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
ColumnarValueRef::NullableLargeStringArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
ColumnarValueRef::NullableStringViewArray(array) => {
if !CHECK_VALID || array.is_valid(i) {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
ColumnarValueRef::NonNullableArray(array) => {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
ColumnarValueRef::NonNullableLargeStringArray(array) => {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
ColumnarValueRef::NonNullableStringViewArray(array) => {
self.value_buffer
.extend_from_slice(array.value(i).as_bytes());
}
}
}
pub fn append_offset(&mut self) {
let next_offset: i64 = self
.value_buffer
.len()
.try_into()
.expect("byte array offset overflow");
unsafe { self.offsets_buffer.push_unchecked(next_offset) };
}
pub fn finish(self, null_buffer: Option<NullBuffer>) -> LargeStringArray {
let array_builder = ArrayDataBuilder::new(DataType::LargeUtf8)
.len(self.offsets_buffer.len() / size_of::<i64>() - 1)
.add_buffer(self.offsets_buffer.into())
.add_buffer(self.value_buffer.into())
.nulls(null_buffer);
// SAFETY: all data that was appended was valid Large UTF8 and the values
// and offsets were created correctly
let array_data = unsafe { array_builder.build_unchecked() };
LargeStringArray::from(array_data)
}
}
/// Append a new view to the views buffer with the given substr
///
/// # Safety
///
/// original_view must be a valid view (the format described on
/// [`GenericByteViewArray`](arrow::array::GenericByteViewArray).
///
/// # Arguments
/// - views_buffer: The buffer to append the new view to
/// - null_builder: The buffer to append the null value to
/// - original_view: The original view value
/// - substr: The substring to append. Must be a valid substring of the original view
/// - start_offset: The start offset of the substring in the view
pub fn make_and_append_view(
views_buffer: &mut Vec<u128>,
null_builder: &mut NullBufferBuilder,
original_view: &u128,
substr: &str,
start_offset: u32,
) {
let substr_len = substr.len();
let sub_view = if substr_len > 12 {
let view = ByteView::from(*original_view);
make_view(
substr.as_bytes(),
view.buffer_index,
view.offset + start_offset,
)
} else {
// inline value does not need block id or offset
make_view(substr.as_bytes(), 0, 0)
};
views_buffer.push(sub_view);
null_builder.append_non_null();
}
#[derive(Debug)]
pub enum ColumnarValueRef<'a> {
Scalar(&'a [u8]),
NullableArray(&'a StringArray),
NonNullableArray(&'a StringArray),
NullableLargeStringArray(&'a LargeStringArray),
NonNullableLargeStringArray(&'a LargeStringArray),
NullableStringViewArray(&'a StringViewArray),
NonNullableStringViewArray(&'a StringViewArray),
}
impl<'a> ColumnarValueRef<'a> {
#[inline]
pub fn is_valid(&self, i: usize) -> bool {
match &self {
Self::Scalar(_)
| Self::NonNullableArray(_)
| Self::NonNullableLargeStringArray(_)
| Self::NonNullableStringViewArray(_) => true,
Self::NullableArray(array) => array.is_valid(i),
Self::NullableStringViewArray(array) => array.is_valid(i),
Self::NullableLargeStringArray(array) => array.is_valid(i),
}
}
#[inline]
pub fn nulls(&self) -> Option<NullBuffer> {
match &self {
Self::Scalar(_)
| Self::NonNullableArray(_)
| Self::NonNullableStringViewArray(_)
| Self::NonNullableLargeStringArray(_) => None,
Self::NullableArray(array) => array.nulls().cloned(),
Self::NullableStringViewArray(array) => array.nulls().cloned(),
Self::NullableLargeStringArray(array) => array.nulls().cloned(),
}
}
}