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arrow_row/
lib.rs

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17
18//! A comparable row-oriented representation of a collection of [`Array`].
19//!
20//! [`Row`]s are [normalized for sorting], and can therefore be very efficiently [compared],
21//! using [`memcmp`] under the hood, or used in [non-comparison sorts] such as [radix sort].
22//! This makes the row format ideal for implementing efficient multi-column sorting,
23//! grouping, aggregation, windowing and more, as described in more detail
24//! [in this blog post](https://arrow.apache.org/blog/2022/11/07/multi-column-sorts-in-arrow-rust-part-1/).
25//!
26//! For example, given three input [`Array`], [`RowConverter`] creates byte
27//! sequences that [compare] the same as when using [`lexsort`].
28//!
29//! ```text
30//!    ┌─────┐   ┌─────┐   ┌─────┐
31//!    │     │   │     │   │     │
32//!    ├─────┤ ┌ ┼─────┼ ─ ┼─────┼ ┐              ┏━━━━━━━━━━━━━┓
33//!    │     │   │     │   │     │  ─────────────▶┃             ┃
34//!    ├─────┤ └ ┼─────┼ ─ ┼─────┼ ┘              ┗━━━━━━━━━━━━━┛
35//!    │     │   │     │   │     │
36//!    └─────┘   └─────┘   └─────┘
37//!                ...
38//!    ┌─────┐ ┌ ┬─────┬ ─ ┬─────┬ ┐              ┏━━━━━━━━┓
39//!    │     │   │     │   │     │  ─────────────▶┃        ┃
40//!    └─────┘ └ ┴─────┴ ─ ┴─────┴ ┘              ┗━━━━━━━━┛
41//!     UInt64      Utf8     F64
42//!
43//!           Input Arrays                          Row Format
44//!     (Columns)
45//! ```
46//!
47//! _[`Rows`] must be generated by the same [`RowConverter`] for the comparison
48//! to be meaningful._
49//!
50//! # Basic Example
51//! ```
52//! # use std::sync::Arc;
53//! # use arrow_row::{RowConverter, SortField};
54//! # use arrow_array::{ArrayRef, Int32Array, StringArray};
55//! # use arrow_array::cast::{AsArray, as_string_array};
56//! # use arrow_array::types::Int32Type;
57//! # use arrow_schema::DataType;
58//!
59//! let a1 = Arc::new(Int32Array::from_iter_values([-1, -1, 0, 3, 3])) as ArrayRef;
60//! let a2 = Arc::new(StringArray::from_iter_values(["a", "b", "c", "d", "d"])) as ArrayRef;
61//! let arrays = vec![a1, a2];
62//!
63//! // Convert arrays to rows
64//! let converter = RowConverter::new(vec![
65//!     SortField::new(DataType::Int32),
66//!     SortField::new(DataType::Utf8),
67//! ]).unwrap();
68//! let rows = converter.convert_columns(&arrays).unwrap();
69//!
70//! // Compare rows
71//! for i in 0..4 {
72//!     assert!(rows.row(i) <= rows.row(i + 1));
73//! }
74//! assert_eq!(rows.row(3), rows.row(4));
75//!
76//! // Convert rows back to arrays
77//! let converted = converter.convert_rows(&rows).unwrap();
78//! assert_eq!(arrays, converted);
79//!
80//! // Compare rows from different arrays
81//! let a1 = Arc::new(Int32Array::from_iter_values([3, 4])) as ArrayRef;
82//! let a2 = Arc::new(StringArray::from_iter_values(["e", "f"])) as ArrayRef;
83//! let arrays = vec![a1, a2];
84//! let rows2 = converter.convert_columns(&arrays).unwrap();
85//!
86//! assert!(rows.row(4) < rows2.row(0));
87//! assert!(rows.row(4) < rows2.row(1));
88//!
89//! // Convert selection of rows back to arrays
90//! let selection = [rows.row(0), rows2.row(1), rows.row(2), rows2.row(0)];
91//! let converted = converter.convert_rows(selection).unwrap();
92//! let c1 = converted[0].as_primitive::<Int32Type>();
93//! assert_eq!(c1.values(), &[-1, 4, 0, 3]);
94//!
95//! let c2 = converted[1].as_string::<i32>();
96//! let c2_values: Vec<_> = c2.iter().flatten().collect();
97//! assert_eq!(&c2_values, &["a", "f", "c", "e"]);
98//! ```
99//!
100//! # Lexicographic Sorts (lexsort)
101//!
102//! The row format can also be used to implement a fast multi-column / lexicographic sort
103//!
104//! ```
105//! # use arrow_row::{RowConverter, SortField};
106//! # use arrow_array::{ArrayRef, UInt32Array};
107//! fn lexsort_to_indices(arrays: &[ArrayRef]) -> UInt32Array {
108//!     let fields = arrays
109//!         .iter()
110//!         .map(|a| SortField::new(a.data_type().clone()))
111//!         .collect();
112//!     let converter = RowConverter::new(fields).unwrap();
113//!     let rows = converter.convert_columns(arrays).unwrap();
114//!     let mut sort: Vec<_> = rows.iter().enumerate().collect();
115//!     sort.sort_unstable_by(|(_, a), (_, b)| a.cmp(b));
116//!     UInt32Array::from_iter_values(sort.iter().map(|(i, _)| *i as u32))
117//! }
118//! ```
119//!
120//! # Flattening Dictionaries
121//!
122//! For performance reasons, dictionary arrays are flattened ("hydrated") to their
123//! underlying values during row conversion. See [the issue] for more details.
124//!
125//! This means that the arrays that come out of [`RowConverter::convert_rows`]
126//! may not have the same data types as the input arrays. For example, encoding
127//! a `Dictionary<Int8, Utf8>` and then will come out as a `Utf8` array.
128//!
129//! ```
130//! # use arrow_array::{Array, ArrayRef, DictionaryArray};
131//! # use arrow_array::types::Int8Type;
132//! # use arrow_row::{RowConverter, SortField};
133//! # use arrow_schema::DataType;
134//! # use std::sync::Arc;
135//! // Input is a Dictionary array
136//! let dict: DictionaryArray::<Int8Type> = ["a", "b", "c", "a", "b"].into_iter().collect();
137//! let sort_fields = vec![SortField::new(dict.data_type().clone())];
138//! let arrays = vec![Arc::new(dict) as ArrayRef];
139//! let converter = RowConverter::new(sort_fields).unwrap();
140//! // Convert to rows
141//! let rows = converter.convert_columns(&arrays).unwrap();
142//! let converted = converter.convert_rows(&rows).unwrap();
143//! // result was a Utf8 array, not a Dictionary array
144//! assert_eq!(converted[0].data_type(), &DataType::Utf8);
145//! ```
146//!
147//! [non-comparison sorts]: https://en.wikipedia.org/wiki/Sorting_algorithm#Non-comparison_sorts
148//! [radix sort]: https://en.wikipedia.org/wiki/Radix_sort
149//! [normalized for sorting]: http://wwwlgis.informatik.uni-kl.de/archiv/wwwdvs.informatik.uni-kl.de/courses/DBSREAL/SS2005/Vorlesungsunterlagen/Implementing_Sorting.pdf
150//! [`memcmp`]: https://www.man7.org/linux/man-pages/man3/memcmp.3.html
151//! [`lexsort`]: https://docs.rs/arrow-ord/latest/arrow_ord/sort/fn.lexsort.html
152//! [compared]: PartialOrd
153//! [compare]: PartialOrd
154//! [the issue]: https://github.com/apache/arrow-rs/issues/4811
155
156#![doc(
157    html_logo_url = "https://arrow.apache.org/img/arrow-logo_chevrons_black-txt_white-bg.svg",
158    html_favicon_url = "https://arrow.apache.org/img/arrow-logo_chevrons_black-txt_transparent-bg.svg"
159)]
160#![cfg_attr(docsrs, feature(doc_cfg))]
161#![warn(missing_docs)]
162use std::cmp::Ordering;
163use std::hash::{Hash, Hasher};
164use std::iter::Map;
165use std::slice::Windows;
166use std::sync::Arc;
167
168use arrow_array::cast::*;
169use arrow_array::types::{ArrowDictionaryKeyType, ByteArrayType, ByteViewType};
170use arrow_array::*;
171use arrow_buffer::{ArrowNativeType, Buffer, OffsetBuffer, ScalarBuffer};
172use arrow_data::{ArrayData, ArrayDataBuilder};
173use arrow_schema::*;
174use variable::{decode_binary_view, decode_string_view};
175
176use crate::fixed::{decode_bool, decode_fixed_size_binary, decode_primitive};
177use crate::list::{compute_lengths_fixed_size_list, encode_fixed_size_list};
178use crate::variable::{decode_binary, decode_string};
179use arrow_array::types::{Int16Type, Int32Type, Int64Type};
180
181mod fixed;
182mod list;
183mod run;
184mod variable;
185
186/// Converts [`ArrayRef`] columns into a [row-oriented](self) format.
187///
188/// *Note: The encoding of the row format may change from release to release.*
189///
190/// ## Overview
191///
192/// The row format is a variable length byte sequence created by
193/// concatenating the encoded form of each column. The encoding for
194/// each column depends on its datatype (and sort options).
195///
196/// The encoding is carefully designed in such a way that escaping is
197/// unnecessary: it is never ambiguous as to whether a byte is part of
198/// a sentinel (e.g. null) or a value.
199///
200/// ## Unsigned Integer Encoding
201///
202/// A null integer is encoded as a `0_u8`, followed by a zero-ed number of bytes corresponding
203/// to the integer's length.
204///
205/// A valid integer is encoded as `1_u8`, followed by the big-endian representation of the
206/// integer.
207///
208/// ```text
209///               ┌──┬──┬──┬──┐      ┌──┬──┬──┬──┬──┐
210///    3          │03│00│00│00│      │01│00│00│00│03│
211///               └──┴──┴──┴──┘      └──┴──┴──┴──┴──┘
212///               ┌──┬──┬──┬──┐      ┌──┬──┬──┬──┬──┐
213///   258         │02│01│00│00│      │01│00│00│01│02│
214///               └──┴──┴──┴──┘      └──┴──┴──┴──┴──┘
215///               ┌──┬──┬──┬──┐      ┌──┬──┬──┬──┬──┐
216///  23423        │7F│5B│00│00│      │01│00│00│5B│7F│
217///               └──┴──┴──┴──┘      └──┴──┴──┴──┴──┘
218///               ┌──┬──┬──┬──┐      ┌──┬──┬──┬──┬──┐
219///  NULL         │??│??│??│??│      │00│00│00│00│00│
220///               └──┴──┴──┴──┘      └──┴──┴──┴──┴──┘
221///
222///              32-bit (4 bytes)        Row Format
223///  Value        Little Endian
224/// ```
225///
226/// ## Signed Integer Encoding
227///
228/// Signed integers have their most significant sign bit flipped, and are then encoded in the
229/// same manner as an unsigned integer.
230///
231/// ```text
232///        ┌──┬──┬──┬──┐       ┌──┬──┬──┬──┐       ┌──┬──┬──┬──┬──┐
233///     5  │05│00│00│00│       │05│00│00│80│       │01│80│00│00│05│
234///        └──┴──┴──┴──┘       └──┴──┴──┴──┘       └──┴──┴──┴──┴──┘
235///        ┌──┬──┬──┬──┐       ┌──┬──┬──┬──┐       ┌──┬──┬──┬──┬──┐
236///    -5  │FB│FF│FF│FF│       │FB│FF│FF│7F│       │01│7F│FF│FF│FB│
237///        └──┴──┴──┴──┘       └──┴──┴──┴──┘       └──┴──┴──┴──┴──┘
238///
239///  Value  32-bit (4 bytes)    High bit flipped      Row Format
240///          Little Endian
241/// ```
242///
243/// ## Float Encoding
244///
245/// Floats are converted from IEEE 754 representation to a signed integer representation
246/// by flipping all bar the sign bit if they are negative.
247///
248/// They are then encoded in the same manner as a signed integer.
249///
250/// ## Fixed Length Bytes Encoding
251///
252/// Fixed length bytes are encoded in the same fashion as primitive types above.
253///
254/// For a fixed length array of length `n`:
255///
256/// A null is encoded as `0_u8` null sentinel followed by `n` `0_u8` bytes
257///
258/// A valid value is encoded as `1_u8` followed by the value bytes
259///
260/// ## Variable Length Bytes (including Strings) Encoding
261///
262/// A null is encoded as a `0_u8`.
263///
264/// An empty byte array is encoded as `1_u8`.
265///
266/// A non-null, non-empty byte array is encoded as `2_u8` followed by the byte array
267/// encoded using a block based scheme described below.
268///
269/// The byte array is broken up into fixed-width blocks, each block is written in turn
270/// to the output, followed by `0xFF_u8`. The final block is padded to 32-bytes
271/// with `0_u8` and written to the output, followed by the un-padded length in bytes
272/// of this final block as a `u8`. The first 4 blocks have a length of 8, with subsequent
273/// blocks using a length of 32, this is to reduce space amplification for small strings.
274///
275/// Note the following example encodings use a block size of 4 bytes for brevity:
276///
277/// ```text
278///                       ┌───┬───┬───┬───┬───┬───┐
279///  "MEEP"               │02 │'M'│'E'│'E'│'P'│04 │
280///                       └───┴───┴───┴───┴───┴───┘
281///
282///                       ┌───┐
283///  ""                   │01 |
284///                       └───┘
285///
286///  NULL                 ┌───┐
287///                       │00 │
288///                       └───┘
289///
290/// "Defenestration"      ┌───┬───┬───┬───┬───┬───┐
291///                       │02 │'D'│'e'│'f'│'e'│FF │
292///                       └───┼───┼───┼───┼───┼───┤
293///                           │'n'│'e'│'s'│'t'│FF │
294///                           ├───┼───┼───┼───┼───┤
295///                           │'r'│'a'│'t'│'r'│FF │
296///                           ├───┼───┼───┼───┼───┤
297///                           │'a'│'t'│'i'│'o'│FF │
298///                           ├───┼───┼───┼───┼───┤
299///                           │'n'│00 │00 │00 │01 │
300///                           └───┴───┴───┴───┴───┘
301/// ```
302///
303/// This approach is loosely inspired by [COBS] encoding, and chosen over more traditional
304/// [byte stuffing] as it is more amenable to vectorisation, in particular AVX-256.
305///
306/// ## Dictionary Encoding
307///
308/// Dictionary encoded arrays are hydrated to their underlying values
309///
310/// ## REE Encoding
311///
312/// REE (Run End Encoding) arrays, A form of Run Length Encoding, are hydrated to their underlying values.
313///
314/// ## Struct Encoding
315///
316/// A null is encoded as a `0_u8`.
317///
318/// A valid value is encoded as `1_u8` followed by the row encoding of each child.
319///
320/// This encoding effectively flattens the schema in a depth-first fashion.
321///
322/// For example
323///
324/// ```text
325/// ┌───────┬────────────────────────┬───────┐
326/// │ Int32 │ Struct[Int32, Float32] │ Int32 │
327/// └───────┴────────────────────────┴───────┘
328/// ```
329///
330/// Is encoded as
331///
332/// ```text
333/// ┌───────┬───────────────┬───────┬─────────┬───────┐
334/// │ Int32 │ Null Sentinel │ Int32 │ Float32 │ Int32 │
335/// └───────┴───────────────┴───────┴─────────┴───────┘
336/// ```
337///
338/// ## List Encoding
339///
340/// Lists are encoded by first encoding all child elements to the row format.
341///
342/// A list value is then encoded as the concatenation of each of the child elements,
343/// separately encoded using the variable length encoding described above, followed
344/// by the variable length encoding of an empty byte array.
345///
346/// For example given:
347///
348/// ```text
349/// [1_u8, 2_u8, 3_u8]
350/// [1_u8, null]
351/// []
352/// null
353/// ```
354///
355/// The elements would be converted to:
356///
357/// ```text
358///     ┌──┬──┐     ┌──┬──┐     ┌──┬──┐     ┌──┬──┐        ┌──┬──┐
359///  1  │01│01│  2  │01│02│  3  │01│03│  1  │01│01│  null  │00│00│
360///     └──┴──┘     └──┴──┘     └──┴──┘     └──┴──┘        └──┴──┘
361///```
362///
363/// Which would be encoded as
364///
365/// ```text
366///                         ┌──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┐
367///  [1_u8, 2_u8, 3_u8]     │02│01│01│00│00│02│02│01│02│00│00│02│02│01│03│00│00│02│01│
368///                         └──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┘
369///                          └──── 1_u8 ────┘   └──── 2_u8 ────┘  └──── 3_u8 ────┘
370///
371///                         ┌──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┐
372///  [1_u8, null]           │02│01│01│00│00│02│02│00│00│00│00│02│01│
373///                         └──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┘
374///                          └──── 1_u8 ────┘   └──── null ────┘
375///
376///```
377///
378/// With `[]` represented by an empty byte array, and `null` a null byte array.
379///
380/// ## Fixed Size List Encoding
381///
382/// Fixed Size Lists are encoded by first encoding all child elements to the row format.
383///
384/// A non-null list value is then encoded as 0x01 followed by the concatenation of each
385/// of the child elements. A null list value is encoded as a null marker.
386///
387/// For example given:
388///
389/// ```text
390/// [1_u8, 2_u8]
391/// [3_u8, null]
392/// null
393/// ```
394///
395/// The elements would be converted to:
396///
397/// ```text
398///     ┌──┬──┐     ┌──┬──┐     ┌──┬──┐        ┌──┬──┐
399///  1  │01│01│  2  │01│02│  3  │01│03│  null  │00│00│
400///     └──┴──┘     └──┴──┘     └──┴──┘        └──┴──┘
401///```
402///
403/// Which would be encoded as
404///
405/// ```text
406///                 ┌──┬──┬──┬──┬──┐
407///  [1_u8, 2_u8]   │01│01│01│01│02│
408///                 └──┴──┴──┴──┴──┘
409///                     └ 1 ┘ └ 2 ┘
410///                 ┌──┬──┬──┬──┬──┐
411///  [3_u8, null]   │01│01│03│00│00│
412///                 └──┴──┴──┴──┴──┘
413///                     └ 1 ┘ └null┘
414///                 ┌──┐
415///  null           │00│
416///                 └──┘
417///
418///```
419///
420/// ## ListView Encoding
421///
422/// ListView arrays differ from List arrays in their representation: instead of using
423/// consecutive offset pairs to define each list, ListView uses explicit offset and size
424/// pairs for each element. This allows ListView elements to reference arbitrary (potentially
425/// overlapping) regions of the child array.
426///
427/// Despite this structural difference, ListView uses the **same row encoding as List**.
428/// Each list value is encoded as the concatenation of its child elements (each separately
429/// variable-length encoded), followed by a variable-length encoded empty byte array terminator.
430///
431/// **Important**: When a ListView is decoded back from row format, it is still a
432/// ListView, but any child element sharing that may have existed in the original
433/// (where multiple list entries could reference overlapping regions of the child
434/// array) is **not preserved** - each list's children are decoded independently
435/// with sequential offsets.
436///
437/// For example, given a ListView with offset/size pairs:
438///
439/// ```text
440/// offsets: [0, 1, 0]
441/// sizes:   [2, 2, 0]
442/// values:  [1_u8, 2_u8, 3_u8]
443///
444/// Resulting lists:
445/// [1_u8, 2_u8]  (offset=0, size=2 -> values[0..2])
446/// [2_u8, 3_u8]  (offset=1, size=2 -> values[1..3])
447/// []            (offset=0, size=0 -> empty)
448/// ```
449///
450/// The elements would be encoded identically to List encoding:
451///
452/// ```text
453///                         ┌──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┐
454///  [1_u8, 2_u8]           │02│01│01│00│00│02│02│01│02│00│00│02│01│
455///                         └──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┘
456///                          └──── 1_u8 ────┘   └──── 2_u8 ────┘
457///
458///                         ┌──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┬──┐
459///  [2_u8, 3_u8]           │02│01│02│00│00│02│02│01│03│00│00│02│01│
460///                         └──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┴──┘
461///                          └──── 2_u8 ────┘   └──── 3_u8 ────┘
462///
463///```
464///
465/// Note that element `2_u8` appears in both encoded rows, even though it was shared
466/// in the original ListView, and `[]` is represented by an empty byte array.
467///
468/// ## Union Encoding
469///
470/// A union value is encoded as a single type-id byte followed by the row encoding of the selected child value.
471/// The type-id byte is always present; union arrays have no top-level null marker, so nulls are represented by the child encoding.
472///
473/// For example, given a union of Int32 (type_id = 0) and Utf8 (type_id = 1):
474///
475/// ```text
476///                           ┌──┬──────────────┐
477///  3                        │00│01│80│00│00│03│
478///                           └──┴──────────────┘
479///                            │  └─ signed integer encoding (non-null)
480///                            └──── type_id
481///
482///                           ┌──┬────────────────────────────────┐
483/// "abc"                     │01│02│'a'│'b'│'c'│00│00│00│00│00│03│
484///                           └──┴────────────────────────────────┘
485///                            │  └─ string encoding (non-null)
486///                            └──── type_id
487///
488///                           ┌──┬──────────────┐
489/// null Int32                │00│00│00│00│00│00│
490///                           └──┴──────────────┘
491///                            │  └─ signed integer encoding (null)
492///                            └──── type_id
493///
494///                           ┌──┬──┐
495/// null Utf8                 │01│00│
496///                           └──┴──┘
497///                            │  └─ string encoding (null)
498///                            └──── type_id
499/// ```
500///
501/// See [`UnionArray`] for more details on union types.
502///
503/// # Ordering
504///
505/// ## Float Ordering
506///
507/// Floats are totally ordered in accordance to the `totalOrder` predicate as defined
508/// in the IEEE 754 (2008 revision) floating point standard.
509///
510/// The ordering established by this does not always agree with the
511/// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
512/// they consider negative and positive zero equal, while this does not
513///
514/// ## Null Ordering
515///
516/// The encoding described above will order nulls first, this can be inverted by representing
517/// nulls as `0xFF_u8` instead of `0_u8`
518///
519/// ## Union Ordering
520///
521/// Values of the same type are ordered according to the ordering of that type.
522/// Values of different types are ordered by their type id.
523/// The type_id is negated when descending order is specified.
524///
525/// ## Reverse Column Ordering
526///
527/// The order of a given column can be reversed by negating the encoded bytes of non-null values
528///
529/// [COBS]: https://en.wikipedia.org/wiki/Consistent_Overhead_Byte_Stuffing
530/// [byte stuffing]: https://en.wikipedia.org/wiki/High-Level_Data_Link_Control#Asynchronous_framing
531#[derive(Debug)]
532pub struct RowConverter {
533    fields: Arc<[SortField]>,
534    /// State for codecs
535    codecs: Vec<Codec>,
536}
537
538#[derive(Debug)]
539enum Codec {
540    /// No additional codec state is necessary
541    Stateless,
542    /// A row converter for the dictionary values
543    /// and the encoding of a row containing only nulls
544    Dictionary(RowConverter, OwnedRow),
545    /// A row converter for the child fields
546    /// and the encoding of a row containing only nulls
547    Struct(RowConverter, OwnedRow),
548    /// A row converter for the child field
549    List(RowConverter),
550    /// A row converter for the values array of a run-end encoded array
551    RunEndEncoded(RowConverter),
552    /// Row converters for each union field (indexed by field position)
553    /// the type_ids for each field position, and the encoding of null rows for each field
554    Union(Vec<RowConverter>, Vec<i8>, Vec<OwnedRow>),
555}
556
557/// Computes the minimum offset and maximum end (offset + size) for a ListView array.
558/// Returns (min_offset, max_end) which can be used to slice the values array.
559fn compute_list_view_bounds<O: OffsetSizeTrait>(array: &GenericListViewArray<O>) -> (usize, usize) {
560    if array.is_empty() {
561        return (0, 0);
562    }
563
564    let offsets = array.value_offsets();
565    let sizes = array.value_sizes();
566    let values_len = array.values().len();
567
568    let mut min_offset = usize::MAX;
569    let mut max_end = 0usize;
570
571    for i in 0..array.len() {
572        let offset = offsets[i].as_usize();
573        let size = sizes[i].as_usize();
574        let end = offset + size;
575
576        if size > 0 {
577            min_offset = min_offset.min(offset);
578            max_end = max_end.max(end);
579        }
580
581        // Early exit if we've found the full range of the values array. This is possible with
582        // ListViews since offsets and sizes are arbitrary and the full range can be covered early
583        // in the iteration contrary to regular Lists.
584        if min_offset == 0 && max_end == values_len {
585            break;
586        }
587    }
588
589    if min_offset == usize::MAX {
590        // All lists are empty
591        (0, 0)
592    } else {
593        (min_offset, max_end)
594    }
595}
596
597impl Codec {
598    fn new(sort_field: &SortField) -> Result<Self, ArrowError> {
599        match &sort_field.data_type {
600            DataType::Dictionary(_, values) => {
601                let sort_field =
602                    SortField::new_with_options(values.as_ref().clone(), sort_field.options);
603
604                let converter = RowConverter::new(vec![sort_field])?;
605                let null_array = new_null_array(values.as_ref(), 1);
606                let nulls = converter.convert_columns(&[null_array])?;
607
608                let owned = OwnedRow {
609                    data: nulls.buffer.into(),
610                    config: nulls.config,
611                };
612                Ok(Self::Dictionary(converter, owned))
613            }
614            DataType::RunEndEncoded(_, values) => {
615                // Similar to List implementation
616                let options = SortOptions {
617                    descending: false,
618                    nulls_first: sort_field.options.nulls_first != sort_field.options.descending,
619                };
620
621                let field = SortField::new_with_options(values.data_type().clone(), options);
622                let converter = RowConverter::new(vec![field])?;
623                Ok(Self::RunEndEncoded(converter))
624            }
625            d if !d.is_nested() => Ok(Self::Stateless),
626            DataType::List(f)
627            | DataType::LargeList(f)
628            | DataType::ListView(f)
629            | DataType::LargeListView(f) => {
630                // The encoded contents will be inverted if descending is set to true
631                // As such we set `descending` to false and negate nulls first if it
632                // it set to true
633                let options = SortOptions {
634                    descending: false,
635                    nulls_first: sort_field.options.nulls_first != sort_field.options.descending,
636                };
637
638                let field = SortField::new_with_options(f.data_type().clone(), options);
639                let converter = RowConverter::new(vec![field])?;
640                Ok(Self::List(converter))
641            }
642            DataType::FixedSizeList(f, _) => {
643                let field = SortField::new_with_options(f.data_type().clone(), sort_field.options);
644                let converter = RowConverter::new(vec![field])?;
645                Ok(Self::List(converter))
646            }
647            DataType::Struct(f) => {
648                let sort_fields = f
649                    .iter()
650                    .map(|x| SortField::new_with_options(x.data_type().clone(), sort_field.options))
651                    .collect();
652
653                let converter = RowConverter::new(sort_fields)?;
654                let nulls: Vec<_> = f.iter().map(|x| new_null_array(x.data_type(), 1)).collect();
655
656                let nulls = converter.convert_columns(&nulls)?;
657                let owned = OwnedRow {
658                    data: nulls.buffer.into(),
659                    config: nulls.config,
660                };
661
662                Ok(Self::Struct(converter, owned))
663            }
664            DataType::Union(fields, _mode) => {
665                // similar to dictionaries and lists, we set descending to false and negate nulls_first
666                // since the encoded contents will be inverted if descending is set
667                let options = SortOptions {
668                    descending: false,
669                    nulls_first: sort_field.options.nulls_first != sort_field.options.descending,
670                };
671
672                let mut converters = Vec::with_capacity(fields.len());
673                let mut type_ids = Vec::with_capacity(fields.len());
674                let mut null_rows = Vec::with_capacity(fields.len());
675
676                for (type_id, field) in fields.iter() {
677                    let sort_field =
678                        SortField::new_with_options(field.data_type().clone(), options);
679                    let converter = RowConverter::new(vec![sort_field])?;
680
681                    let null_array = new_null_array(field.data_type(), 1);
682                    let nulls = converter.convert_columns(&[null_array])?;
683                    let owned = OwnedRow {
684                        data: nulls.buffer.into(),
685                        config: nulls.config,
686                    };
687
688                    converters.push(converter);
689                    type_ids.push(type_id);
690                    null_rows.push(owned);
691                }
692
693                Ok(Self::Union(converters, type_ids, null_rows))
694            }
695            _ => Err(ArrowError::NotYetImplemented(format!(
696                "not yet implemented: {:?}",
697                sort_field.data_type
698            ))),
699        }
700    }
701
702    fn encoder(&self, array: &dyn Array) -> Result<Encoder<'_>, ArrowError> {
703        match self {
704            Codec::Stateless => Ok(Encoder::Stateless),
705            Codec::Dictionary(converter, nulls) => {
706                let values = array.as_any_dictionary().values().clone();
707                let rows = converter.convert_columns(&[values])?;
708                Ok(Encoder::Dictionary(rows, nulls.row()))
709            }
710            Codec::Struct(converter, null) => {
711                let v = as_struct_array(array);
712                let rows = converter.convert_columns(v.columns())?;
713                Ok(Encoder::Struct(rows, null.row()))
714            }
715            Codec::List(converter) => {
716                let values = match array.data_type() {
717                    DataType::List(_) => {
718                        let list_array = as_list_array(array);
719                        let first_offset = list_array.offsets()[0] as usize;
720                        let last_offset =
721                            list_array.offsets()[list_array.offsets().len() - 1] as usize;
722
723                        // values can include more data than referenced in the ListArray, only encode
724                        // the referenced values.
725                        list_array
726                            .values()
727                            .slice(first_offset, last_offset - first_offset)
728                    }
729                    DataType::LargeList(_) => {
730                        let list_array = as_large_list_array(array);
731
732                        let first_offset = list_array.offsets()[0] as usize;
733                        let last_offset =
734                            list_array.offsets()[list_array.offsets().len() - 1] as usize;
735
736                        // values can include more data than referenced in the LargeListArray, only encode
737                        // the referenced values.
738                        list_array
739                            .values()
740                            .slice(first_offset, last_offset - first_offset)
741                    }
742                    DataType::ListView(_) => {
743                        let list_view_array = array.as_list_view::<i32>();
744                        let (min_offset, max_end) = compute_list_view_bounds(list_view_array);
745                        list_view_array
746                            .values()
747                            .slice(min_offset, max_end - min_offset)
748                    }
749                    DataType::LargeListView(_) => {
750                        let list_view_array = array.as_list_view::<i64>();
751                        let (min_offset, max_end) = compute_list_view_bounds(list_view_array);
752                        list_view_array
753                            .values()
754                            .slice(min_offset, max_end - min_offset)
755                    }
756                    DataType::FixedSizeList(_, _) => {
757                        as_fixed_size_list_array(array).values().clone()
758                    }
759                    _ => unreachable!(),
760                };
761                let rows = converter.convert_columns(&[values])?;
762                Ok(Encoder::List(rows))
763            }
764            Codec::RunEndEncoded(converter) => {
765                let values = match array.data_type() {
766                    DataType::RunEndEncoded(r, _) => match r.data_type() {
767                        DataType::Int16 => array.as_run::<Int16Type>().values_slice(),
768                        DataType::Int32 => array.as_run::<Int32Type>().values_slice(),
769                        DataType::Int64 => array.as_run::<Int64Type>().values_slice(),
770                        _ => unreachable!("Unsupported run end index type: {r:?}"),
771                    },
772                    _ => unreachable!(),
773                };
774                let rows = converter.convert_columns(std::slice::from_ref(&values))?;
775                Ok(Encoder::RunEndEncoded(rows))
776            }
777            Codec::Union(converters, field_to_type_ids, _) => {
778                let union_array = array
779                    .as_any()
780                    .downcast_ref::<UnionArray>()
781                    .expect("expected Union array");
782
783                let type_ids = union_array.type_ids().clone();
784                let offsets = union_array.offsets().cloned();
785
786                let mut child_rows = Vec::with_capacity(converters.len());
787                for (field_idx, converter) in converters.iter().enumerate() {
788                    let type_id = field_to_type_ids[field_idx];
789                    let child_array = union_array.child(type_id);
790                    let rows = converter.convert_columns(std::slice::from_ref(child_array))?;
791                    child_rows.push(rows);
792                }
793
794                Ok(Encoder::Union {
795                    child_rows,
796                    field_to_type_ids: field_to_type_ids.clone(),
797                    type_ids,
798                    offsets,
799                })
800            }
801        }
802    }
803
804    fn size(&self) -> usize {
805        match self {
806            Codec::Stateless => 0,
807            Codec::Dictionary(converter, nulls) => converter.size() + nulls.data.len(),
808            Codec::Struct(converter, nulls) => converter.size() + nulls.data.len(),
809            Codec::List(converter) => converter.size(),
810            Codec::RunEndEncoded(converter) => converter.size(),
811            Codec::Union(converters, _, null_rows) => {
812                converters.iter().map(|c| c.size()).sum::<usize>()
813                    + null_rows.iter().map(|n| n.data.len()).sum::<usize>()
814            }
815        }
816    }
817}
818
819#[derive(Debug)]
820enum Encoder<'a> {
821    /// No additional encoder state is necessary
822    Stateless,
823    /// The encoding of the child array and the encoding of a null row
824    Dictionary(Rows, Row<'a>),
825    /// The row encoding of the child arrays and the encoding of a null row
826    ///
827    /// It is necessary to encode to a temporary [`Rows`] to avoid serializing
828    /// values that are masked by a null in the parent StructArray, otherwise
829    /// this would establish an ordering between semantically null values
830    Struct(Rows, Row<'a>),
831    /// The row encoding of the child array
832    List(Rows),
833    /// The row encoding of the values array
834    RunEndEncoded(Rows),
835    /// The row encoding of each union field's child array, type_ids buffer, offsets buffer (for Dense), and mode
836    Union {
837        child_rows: Vec<Rows>,
838        field_to_type_ids: Vec<i8>,
839        type_ids: ScalarBuffer<i8>,
840        offsets: Option<ScalarBuffer<i32>>,
841    },
842}
843
844/// Configure the data type and sort order for a given column
845#[derive(Debug, Clone, PartialEq, Eq)]
846pub struct SortField {
847    /// Sort options
848    options: SortOptions,
849    /// Data type
850    data_type: DataType,
851}
852
853impl SortField {
854    /// Create a new column with the given data type
855    pub fn new(data_type: DataType) -> Self {
856        Self::new_with_options(data_type, Default::default())
857    }
858
859    /// Create a new column with the given data type and [`SortOptions`]
860    pub fn new_with_options(data_type: DataType, options: SortOptions) -> Self {
861        Self { options, data_type }
862    }
863
864    /// Return size of this instance in bytes.
865    ///
866    /// Includes the size of `Self`.
867    pub fn size(&self) -> usize {
868        self.data_type.size() + std::mem::size_of::<Self>() - std::mem::size_of::<DataType>()
869    }
870}
871
872impl RowConverter {
873    /// Create a new [`RowConverter`] with the provided schema
874    pub fn new(fields: Vec<SortField>) -> Result<Self, ArrowError> {
875        if !Self::supports_fields(&fields) {
876            return Err(ArrowError::NotYetImplemented(format!(
877                "Row format support not yet implemented for: {fields:?}"
878            )));
879        }
880
881        let codecs = fields.iter().map(Codec::new).collect::<Result<_, _>>()?;
882        Ok(Self {
883            fields: fields.into(),
884            codecs,
885        })
886    }
887
888    /// Check if the given fields are supported by the row format.
889    pub fn supports_fields(fields: &[SortField]) -> bool {
890        fields.iter().all(|x| Self::supports_datatype(&x.data_type))
891    }
892
893    fn supports_datatype(d: &DataType) -> bool {
894        match d {
895            _ if !d.is_nested() => true,
896            DataType::List(f)
897            | DataType::LargeList(f)
898            | DataType::ListView(f)
899            | DataType::LargeListView(f)
900            | DataType::FixedSizeList(f, _) => Self::supports_datatype(f.data_type()),
901            DataType::Struct(f) => f.iter().all(|x| Self::supports_datatype(x.data_type())),
902            DataType::RunEndEncoded(_, values) => Self::supports_datatype(values.data_type()),
903            DataType::Union(fs, _mode) => fs
904                .iter()
905                .all(|(_, f)| Self::supports_datatype(f.data_type())),
906            _ => false,
907        }
908    }
909
910    /// Convert [`ArrayRef`] columns into [`Rows`]
911    ///
912    /// See [`Row`] for information on when [`Row`] can be compared
913    ///
914    /// See [`Self::convert_rows`] for converting [`Rows`] back into [`ArrayRef`]
915    ///
916    /// # Panics
917    ///
918    /// Panics if the schema of `columns` does not match that provided to [`RowConverter::new`]
919    pub fn convert_columns(&self, columns: &[ArrayRef]) -> Result<Rows, ArrowError> {
920        let num_rows = columns.first().map(|x| x.len()).unwrap_or(0);
921        let mut rows = self.empty_rows(num_rows, 0);
922        self.append(&mut rows, columns)?;
923        Ok(rows)
924    }
925
926    /// Convert [`ArrayRef`] columns appending to an existing [`Rows`]
927    ///
928    /// See [`Row`] for information on when [`Row`] can be compared
929    ///
930    /// # Panics
931    ///
932    /// Panics if
933    /// * The schema of `columns` does not match that provided to [`RowConverter::new`]
934    /// * The provided [`Rows`] were not created by this [`RowConverter`]
935    ///
936    /// ```
937    /// # use std::sync::Arc;
938    /// # use std::collections::HashSet;
939    /// # use arrow_array::cast::AsArray;
940    /// # use arrow_array::StringArray;
941    /// # use arrow_row::{Row, RowConverter, SortField};
942    /// # use arrow_schema::DataType;
943    /// #
944    /// let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
945    /// let a1 = StringArray::from(vec!["hello", "world"]);
946    /// let a2 = StringArray::from(vec!["a", "a", "hello"]);
947    ///
948    /// let mut rows = converter.empty_rows(5, 128);
949    /// converter.append(&mut rows, &[Arc::new(a1)]).unwrap();
950    /// converter.append(&mut rows, &[Arc::new(a2)]).unwrap();
951    ///
952    /// let back = converter.convert_rows(&rows).unwrap();
953    /// let values: Vec<_> = back[0].as_string::<i32>().iter().map(Option::unwrap).collect();
954    /// assert_eq!(&values, &["hello", "world", "a", "a", "hello"]);
955    /// ```
956    pub fn append(&self, rows: &mut Rows, columns: &[ArrayRef]) -> Result<(), ArrowError> {
957        assert!(
958            Arc::ptr_eq(&rows.config.fields, &self.fields),
959            "rows were not produced by this RowConverter"
960        );
961
962        if columns.len() != self.fields.len() {
963            return Err(ArrowError::InvalidArgumentError(format!(
964                "Incorrect number of arrays provided to RowConverter, expected {} got {}",
965                self.fields.len(),
966                columns.len()
967            )));
968        }
969        for colum in columns.iter().skip(1) {
970            if colum.len() != columns[0].len() {
971                return Err(ArrowError::InvalidArgumentError(format!(
972                    "RowConverter columns must all have the same length, expected {} got {}",
973                    columns[0].len(),
974                    colum.len()
975                )));
976            }
977        }
978
979        let encoders = columns
980            .iter()
981            .zip(&self.codecs)
982            .zip(self.fields.iter())
983            .map(|((column, codec), field)| {
984                if !column.data_type().equals_datatype(&field.data_type) {
985                    return Err(ArrowError::InvalidArgumentError(format!(
986                        "RowConverter column schema mismatch, expected {} got {}",
987                        field.data_type,
988                        column.data_type()
989                    )));
990                }
991                codec.encoder(column.as_ref())
992            })
993            .collect::<Result<Vec<_>, _>>()?;
994
995        let write_offset = rows.num_rows();
996        let lengths = row_lengths(columns, &encoders);
997        let total = lengths.extend_offsets(rows.offsets[write_offset], &mut rows.offsets);
998        rows.buffer.resize(total, 0);
999
1000        for ((column, field), encoder) in columns.iter().zip(self.fields.iter()).zip(encoders) {
1001            // We encode a column at a time to minimise dispatch overheads
1002            encode_column(
1003                &mut rows.buffer,
1004                &mut rows.offsets[write_offset..],
1005                column.as_ref(),
1006                field.options,
1007                &encoder,
1008            )
1009        }
1010
1011        if cfg!(debug_assertions) {
1012            assert_eq!(*rows.offsets.last().unwrap(), rows.buffer.len());
1013            rows.offsets
1014                .windows(2)
1015                .for_each(|w| assert!(w[0] <= w[1], "offsets should be monotonic"));
1016        }
1017
1018        Ok(())
1019    }
1020
1021    /// Convert [`Rows`] columns into [`ArrayRef`]
1022    ///
1023    /// See [`Self::convert_columns`] for converting [`ArrayRef`] into [`Rows`]
1024    ///
1025    /// # Panics
1026    ///
1027    /// Panics if the rows were not produced by this [`RowConverter`]
1028    pub fn convert_rows<'a, I>(&self, rows: I) -> Result<Vec<ArrayRef>, ArrowError>
1029    where
1030        I: IntoIterator<Item = Row<'a>>,
1031    {
1032        let mut validate_utf8 = false;
1033        let mut rows: Vec<_> = rows
1034            .into_iter()
1035            .map(|row| {
1036                assert!(
1037                    Arc::ptr_eq(&row.config.fields, &self.fields),
1038                    "rows were not produced by this RowConverter"
1039                );
1040                validate_utf8 |= row.config.validate_utf8;
1041                row.data
1042            })
1043            .collect();
1044
1045        // SAFETY
1046        // We have validated that the rows came from this [`RowConverter`]
1047        // and therefore must be valid
1048        let result = unsafe { self.convert_raw(&mut rows, validate_utf8) }?;
1049
1050        if cfg!(debug_assertions) {
1051            for (i, row) in rows.iter().enumerate() {
1052                if !row.is_empty() {
1053                    return Err(ArrowError::InvalidArgumentError(format!(
1054                        "Codecs {codecs:?} did not consume all bytes for row {i}, remaining bytes: {row:?}",
1055                        codecs = &self.codecs
1056                    )));
1057                }
1058            }
1059        }
1060
1061        Ok(result)
1062    }
1063
1064    /// Returns an empty [`Rows`] with capacity for `row_capacity` rows with
1065    /// a total length of `data_capacity`
1066    ///
1067    /// This can be used to buffer a selection of [`Row`]
1068    ///
1069    /// ```
1070    /// # use std::sync::Arc;
1071    /// # use std::collections::HashSet;
1072    /// # use arrow_array::cast::AsArray;
1073    /// # use arrow_array::StringArray;
1074    /// # use arrow_row::{Row, RowConverter, SortField};
1075    /// # use arrow_schema::DataType;
1076    /// #
1077    /// let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
1078    /// let array = StringArray::from(vec!["hello", "world", "a", "a", "hello"]);
1079    ///
1080    /// // Convert to row format and deduplicate
1081    /// let converted = converter.convert_columns(&[Arc::new(array)]).unwrap();
1082    /// let mut distinct_rows = converter.empty_rows(3, 100);
1083    /// let mut dedup: HashSet<Row> = HashSet::with_capacity(3);
1084    /// converted.iter().filter(|row| dedup.insert(*row)).for_each(|row| distinct_rows.push(row));
1085    ///
1086    /// // Note: we could skip buffering and feed the filtered iterator directly
1087    /// // into convert_rows, this is done for demonstration purposes only
1088    /// let distinct = converter.convert_rows(&distinct_rows).unwrap();
1089    /// let values: Vec<_> = distinct[0].as_string::<i32>().iter().map(Option::unwrap).collect();
1090    /// assert_eq!(&values, &["hello", "world", "a"]);
1091    /// ```
1092    pub fn empty_rows(&self, row_capacity: usize, data_capacity: usize) -> Rows {
1093        let mut offsets = Vec::with_capacity(row_capacity.saturating_add(1));
1094        offsets.push(0);
1095
1096        Rows {
1097            offsets,
1098            buffer: Vec::with_capacity(data_capacity),
1099            config: RowConfig {
1100                fields: self.fields.clone(),
1101                validate_utf8: false,
1102            },
1103        }
1104    }
1105
1106    /// Create a new [Rows] instance from the given binary data.
1107    ///
1108    /// ```
1109    /// # use std::sync::Arc;
1110    /// # use std::collections::HashSet;
1111    /// # use arrow_array::cast::AsArray;
1112    /// # use arrow_array::StringArray;
1113    /// # use arrow_row::{OwnedRow, Row, RowConverter, RowParser, SortField};
1114    /// # use arrow_schema::DataType;
1115    /// #
1116    /// let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
1117    /// let array = StringArray::from(vec!["hello", "world", "a", "a", "hello"]);
1118    /// let rows = converter.convert_columns(&[Arc::new(array)]).unwrap();
1119    ///
1120    /// // We can convert rows into binary format and back in batch.
1121    /// let values: Vec<OwnedRow> = rows.iter().map(|r| r.owned()).collect();
1122    /// let binary = rows.try_into_binary().expect("known-small array");
1123    /// let converted = converter.from_binary(binary.clone());
1124    /// assert!(converted.iter().eq(values.iter().map(|r| r.row())));
1125    /// ```
1126    ///
1127    /// # Panics
1128    ///
1129    /// This function expects the passed [BinaryArray] to contain valid row data as produced by this
1130    /// [RowConverter]. It will panic if any rows are null. Operations on the returned [Rows] may
1131    /// panic if the data is malformed.
1132    pub fn from_binary(&self, array: BinaryArray) -> Rows {
1133        assert_eq!(
1134            array.null_count(),
1135            0,
1136            "can't construct Rows instance from array with nulls"
1137        );
1138        let (offsets, values, _) = array.into_parts();
1139        let offsets = offsets.iter().map(|&i| i.as_usize()).collect();
1140        // Try zero-copy, if it does not succeed, fall back to copying the values.
1141        let buffer = values.into_vec().unwrap_or_else(|values| values.to_vec());
1142        Rows {
1143            buffer,
1144            offsets,
1145            config: RowConfig {
1146                fields: Arc::clone(&self.fields),
1147                validate_utf8: true,
1148            },
1149        }
1150    }
1151
1152    /// Convert raw bytes into [`ArrayRef`]
1153    ///
1154    /// # Safety
1155    ///
1156    /// `rows` must contain valid data for this [`RowConverter`]
1157    unsafe fn convert_raw(
1158        &self,
1159        rows: &mut [&[u8]],
1160        validate_utf8: bool,
1161    ) -> Result<Vec<ArrayRef>, ArrowError> {
1162        self.fields
1163            .iter()
1164            .zip(&self.codecs)
1165            .map(|(field, codec)| unsafe { decode_column(field, rows, codec, validate_utf8) })
1166            .collect()
1167    }
1168
1169    /// Returns a [`RowParser`] that can be used to parse [`Row`] from bytes
1170    pub fn parser(&self) -> RowParser {
1171        RowParser::new(Arc::clone(&self.fields))
1172    }
1173
1174    /// Returns the size of this instance in bytes
1175    ///
1176    /// Includes the size of `Self`.
1177    pub fn size(&self) -> usize {
1178        std::mem::size_of::<Self>()
1179            + self.fields.iter().map(|x| x.size()).sum::<usize>()
1180            + self.codecs.capacity() * std::mem::size_of::<Codec>()
1181            + self.codecs.iter().map(Codec::size).sum::<usize>()
1182    }
1183}
1184
1185/// A [`RowParser`] can be created from a [`RowConverter`] and used to parse bytes to [`Row`]
1186#[derive(Debug)]
1187pub struct RowParser {
1188    config: RowConfig,
1189}
1190
1191impl RowParser {
1192    fn new(fields: Arc<[SortField]>) -> Self {
1193        Self {
1194            config: RowConfig {
1195                fields,
1196                validate_utf8: true,
1197            },
1198        }
1199    }
1200
1201    /// Creates a [`Row`] from the provided `bytes`.
1202    ///
1203    /// `bytes` must be a [`Row`] produced by the [`RowConverter`] associated with
1204    /// this [`RowParser`], otherwise subsequent operations with the produced [`Row`] may panic
1205    pub fn parse<'a>(&'a self, bytes: &'a [u8]) -> Row<'a> {
1206        Row {
1207            data: bytes,
1208            config: &self.config,
1209        }
1210    }
1211}
1212
1213/// The config of a given set of [`Row`]
1214#[derive(Debug, Clone)]
1215struct RowConfig {
1216    /// The schema for these rows
1217    fields: Arc<[SortField]>,
1218    /// Whether to run UTF-8 validation when converting to arrow arrays
1219    validate_utf8: bool,
1220}
1221
1222/// A row-oriented representation of arrow data, that is normalized for comparison.
1223///
1224/// See the [module level documentation](self) and [`RowConverter`] for more details.
1225#[derive(Debug)]
1226pub struct Rows {
1227    /// Underlying row bytes
1228    buffer: Vec<u8>,
1229    /// Row `i` has data `&buffer[offsets[i]..offsets[i+1]]`
1230    offsets: Vec<usize>,
1231    /// The config for these rows
1232    config: RowConfig,
1233}
1234
1235/// The iterator type for [`Rows::lengths`]
1236pub type RowLengthIter<'a> = Map<Windows<'a, usize>, fn(&'a [usize]) -> usize>;
1237
1238impl Rows {
1239    /// Append a [`Row`] to this [`Rows`]
1240    pub fn push(&mut self, row: Row<'_>) {
1241        assert!(
1242            Arc::ptr_eq(&row.config.fields, &self.config.fields),
1243            "row was not produced by this RowConverter"
1244        );
1245        self.config.validate_utf8 |= row.config.validate_utf8;
1246        self.buffer.extend_from_slice(row.data);
1247        self.offsets.push(self.buffer.len())
1248    }
1249
1250    /// Reserve capacity for `row_capacity` rows with a total length of `data_capacity`
1251    pub fn reserve(&mut self, row_capacity: usize, data_capacity: usize) {
1252        self.buffer.reserve(data_capacity);
1253        self.offsets.reserve(row_capacity);
1254    }
1255
1256    /// Returns the row at index `row`
1257    pub fn row(&self, row: usize) -> Row<'_> {
1258        assert!(row + 1 < self.offsets.len());
1259        unsafe { self.row_unchecked(row) }
1260    }
1261
1262    /// Returns the row at `index` without bounds checking
1263    ///
1264    /// # Safety
1265    /// Caller must ensure that `index` is less than the number of offsets (#rows + 1)
1266    pub unsafe fn row_unchecked(&self, index: usize) -> Row<'_> {
1267        let end = unsafe { self.offsets.get_unchecked(index + 1) };
1268        let start = unsafe { self.offsets.get_unchecked(index) };
1269        let data = unsafe { self.buffer.get_unchecked(*start..*end) };
1270        Row {
1271            data,
1272            config: &self.config,
1273        }
1274    }
1275
1276    /// Returns the number of bytes the row at index `row` is occupying,
1277    /// that is, what is the length of the returned [`Row::data`] will be.
1278    pub fn row_len(&self, row: usize) -> usize {
1279        assert!(row + 1 < self.offsets.len());
1280
1281        self.offsets[row + 1] - self.offsets[row]
1282    }
1283
1284    /// Get an iterator over the lengths of each row in this [`Rows`]
1285    pub fn lengths(&self) -> RowLengthIter<'_> {
1286        self.offsets.windows(2).map(|w| w[1] - w[0])
1287    }
1288
1289    /// Sets the length of this [`Rows`] to 0
1290    pub fn clear(&mut self) {
1291        self.offsets.truncate(1);
1292        self.buffer.clear();
1293    }
1294
1295    /// Returns the number of [`Row`] in this [`Rows`]
1296    pub fn num_rows(&self) -> usize {
1297        self.offsets.len() - 1
1298    }
1299
1300    /// Returns an iterator over the [`Row`] in this [`Rows`]
1301    pub fn iter(&self) -> RowsIter<'_> {
1302        self.into_iter()
1303    }
1304
1305    /// Returns the size of this instance in bytes
1306    ///
1307    /// Includes the size of `Self`.
1308    pub fn size(&self) -> usize {
1309        // Size of fields is accounted for as part of RowConverter
1310        std::mem::size_of::<Self>()
1311            + self.buffer.capacity()
1312            + self.offsets.capacity() * std::mem::size_of::<usize>()
1313    }
1314
1315    /// Create a [BinaryArray] from the [Rows] data without reallocating the
1316    /// underlying bytes.
1317    ///
1318    ///
1319    /// ```
1320    /// # use std::sync::Arc;
1321    /// # use std::collections::HashSet;
1322    /// # use arrow_array::cast::AsArray;
1323    /// # use arrow_array::StringArray;
1324    /// # use arrow_row::{OwnedRow, Row, RowConverter, RowParser, SortField};
1325    /// # use arrow_schema::DataType;
1326    /// #
1327    /// let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
1328    /// let array = StringArray::from(vec!["hello", "world", "a", "a", "hello"]);
1329    /// let rows = converter.convert_columns(&[Arc::new(array)]).unwrap();
1330    ///
1331    /// // We can convert rows into binary format and back.
1332    /// let values: Vec<OwnedRow> = rows.iter().map(|r| r.owned()).collect();
1333    /// let binary = rows.try_into_binary().expect("known-small array");
1334    /// let parser = converter.parser();
1335    /// let parsed: Vec<OwnedRow> =
1336    ///   binary.iter().flatten().map(|b| parser.parse(b).owned()).collect();
1337    /// assert_eq!(values, parsed);
1338    /// ```
1339    ///
1340    /// # Errors
1341    ///
1342    /// This function will return an error if there is more data than can be stored in
1343    /// a [BinaryArray] -- i.e. if the total data size is more than 2GiB.
1344    pub fn try_into_binary(self) -> Result<BinaryArray, ArrowError> {
1345        if self.buffer.len() > i32::MAX as usize {
1346            return Err(ArrowError::InvalidArgumentError(format!(
1347                "{}-byte rows buffer too long to convert into a i32-indexed BinaryArray",
1348                self.buffer.len()
1349            )));
1350        }
1351        // We've checked that the buffer length fits in an i32; so all offsets into that buffer should fit as well.
1352        let offsets_scalar = ScalarBuffer::from_iter(self.offsets.into_iter().map(i32::usize_as));
1353        // SAFETY: offsets buffer is nonempty, monotonically increasing, and all represent valid indexes into buffer.
1354        let array = unsafe {
1355            BinaryArray::new_unchecked(
1356                OffsetBuffer::new_unchecked(offsets_scalar),
1357                Buffer::from_vec(self.buffer),
1358                None,
1359            )
1360        };
1361        Ok(array)
1362    }
1363}
1364
1365impl<'a> IntoIterator for &'a Rows {
1366    type Item = Row<'a>;
1367    type IntoIter = RowsIter<'a>;
1368
1369    fn into_iter(self) -> Self::IntoIter {
1370        RowsIter {
1371            rows: self,
1372            start: 0,
1373            end: self.num_rows(),
1374        }
1375    }
1376}
1377
1378/// An iterator over [`Rows`]
1379#[derive(Debug)]
1380pub struct RowsIter<'a> {
1381    rows: &'a Rows,
1382    start: usize,
1383    end: usize,
1384}
1385
1386impl<'a> Iterator for RowsIter<'a> {
1387    type Item = Row<'a>;
1388
1389    fn next(&mut self) -> Option<Self::Item> {
1390        if self.end == self.start {
1391            return None;
1392        }
1393
1394        // SAFETY: We have checked that `start` is less than `end`
1395        let row = unsafe { self.rows.row_unchecked(self.start) };
1396        self.start += 1;
1397        Some(row)
1398    }
1399
1400    fn size_hint(&self) -> (usize, Option<usize>) {
1401        let len = self.len();
1402        (len, Some(len))
1403    }
1404}
1405
1406impl ExactSizeIterator for RowsIter<'_> {
1407    fn len(&self) -> usize {
1408        self.end - self.start
1409    }
1410}
1411
1412impl DoubleEndedIterator for RowsIter<'_> {
1413    fn next_back(&mut self) -> Option<Self::Item> {
1414        if self.end == self.start {
1415            return None;
1416        }
1417        // Safety: We have checked that `start` is less than `end`
1418        let row = unsafe { self.rows.row_unchecked(self.end) };
1419        self.end -= 1;
1420        Some(row)
1421    }
1422}
1423
1424/// A comparable representation of a row.
1425///
1426/// See the [module level documentation](self) for more details.
1427///
1428/// Two [`Row`] can only be compared if they both belong to [`Rows`]
1429/// returned by calls to [`RowConverter::convert_columns`] on the same
1430/// [`RowConverter`]. If different [`RowConverter`]s are used, any
1431/// ordering established by comparing the [`Row`] is arbitrary.
1432#[derive(Debug, Copy, Clone)]
1433pub struct Row<'a> {
1434    data: &'a [u8],
1435    config: &'a RowConfig,
1436}
1437
1438impl<'a> Row<'a> {
1439    /// Create owned version of the row to detach it from the shared [`Rows`].
1440    pub fn owned(&self) -> OwnedRow {
1441        OwnedRow {
1442            data: self.data.into(),
1443            config: self.config.clone(),
1444        }
1445    }
1446
1447    /// The row's bytes, with the lifetime of the underlying data.
1448    pub fn data(&self) -> &'a [u8] {
1449        self.data
1450    }
1451}
1452
1453// Manually derive these as don't wish to include `fields`
1454
1455impl PartialEq for Row<'_> {
1456    #[inline]
1457    fn eq(&self, other: &Self) -> bool {
1458        self.data.eq(other.data)
1459    }
1460}
1461
1462impl Eq for Row<'_> {}
1463
1464impl PartialOrd for Row<'_> {
1465    #[inline]
1466    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1467        Some(self.cmp(other))
1468    }
1469}
1470
1471impl Ord for Row<'_> {
1472    #[inline]
1473    fn cmp(&self, other: &Self) -> Ordering {
1474        self.data.cmp(other.data)
1475    }
1476}
1477
1478impl Hash for Row<'_> {
1479    #[inline]
1480    fn hash<H: Hasher>(&self, state: &mut H) {
1481        self.data.hash(state)
1482    }
1483}
1484
1485impl AsRef<[u8]> for Row<'_> {
1486    #[inline]
1487    fn as_ref(&self) -> &[u8] {
1488        self.data
1489    }
1490}
1491
1492/// Owned version of a [`Row`] that can be moved/cloned freely.
1493///
1494/// This contains the data for the one specific row (not the entire buffer of all rows).
1495#[derive(Debug, Clone)]
1496pub struct OwnedRow {
1497    data: Box<[u8]>,
1498    config: RowConfig,
1499}
1500
1501impl OwnedRow {
1502    /// Get borrowed [`Row`] from owned version.
1503    ///
1504    /// This is helpful if you want to compare an [`OwnedRow`] with a [`Row`].
1505    pub fn row(&self) -> Row<'_> {
1506        Row {
1507            data: &self.data,
1508            config: &self.config,
1509        }
1510    }
1511}
1512
1513// Manually derive these as don't wish to include `fields`. Also we just want to use the same `Row` implementations here.
1514
1515impl PartialEq for OwnedRow {
1516    #[inline]
1517    fn eq(&self, other: &Self) -> bool {
1518        self.row().eq(&other.row())
1519    }
1520}
1521
1522impl Eq for OwnedRow {}
1523
1524impl PartialOrd for OwnedRow {
1525    #[inline]
1526    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
1527        Some(self.cmp(other))
1528    }
1529}
1530
1531impl Ord for OwnedRow {
1532    #[inline]
1533    fn cmp(&self, other: &Self) -> Ordering {
1534        self.row().cmp(&other.row())
1535    }
1536}
1537
1538impl Hash for OwnedRow {
1539    #[inline]
1540    fn hash<H: Hasher>(&self, state: &mut H) {
1541        self.row().hash(state)
1542    }
1543}
1544
1545impl AsRef<[u8]> for OwnedRow {
1546    #[inline]
1547    fn as_ref(&self) -> &[u8] {
1548        &self.data
1549    }
1550}
1551
1552/// Returns the null sentinel, negated if `invert` is true
1553#[inline]
1554fn null_sentinel(options: SortOptions) -> u8 {
1555    match options.nulls_first {
1556        true => 0,
1557        false => 0xFF,
1558    }
1559}
1560
1561/// Stores the lengths of the rows. Lazily materializes lengths for columns with fixed-size types.
1562enum LengthTracker {
1563    /// Fixed state: All rows have length `length`
1564    Fixed { length: usize, num_rows: usize },
1565    /// Variable state: The length of row `i` is `lengths[i] + fixed_length`
1566    Variable {
1567        fixed_length: usize,
1568        lengths: Vec<usize>,
1569    },
1570}
1571
1572impl LengthTracker {
1573    fn new(num_rows: usize) -> Self {
1574        Self::Fixed {
1575            length: 0,
1576            num_rows,
1577        }
1578    }
1579
1580    /// Adds a column of fixed-length elements, each of size `new_length` to the LengthTracker
1581    fn push_fixed(&mut self, new_length: usize) {
1582        match self {
1583            LengthTracker::Fixed { length, .. } => *length += new_length,
1584            LengthTracker::Variable { fixed_length, .. } => *fixed_length += new_length,
1585        }
1586    }
1587
1588    /// Adds a column of possibly variable-length elements, element `i` has length `new_lengths.nth(i)`
1589    fn push_variable(&mut self, new_lengths: impl ExactSizeIterator<Item = usize>) {
1590        match self {
1591            LengthTracker::Fixed { length, .. } => {
1592                *self = LengthTracker::Variable {
1593                    fixed_length: *length,
1594                    lengths: new_lengths.collect(),
1595                }
1596            }
1597            LengthTracker::Variable { lengths, .. } => {
1598                assert_eq!(lengths.len(), new_lengths.len());
1599                lengths
1600                    .iter_mut()
1601                    .zip(new_lengths)
1602                    .for_each(|(length, new_length)| *length += new_length);
1603            }
1604        }
1605    }
1606
1607    /// Returns the tracked row lengths as a slice
1608    fn materialized(&mut self) -> &mut [usize] {
1609        if let LengthTracker::Fixed { length, num_rows } = *self {
1610            *self = LengthTracker::Variable {
1611                fixed_length: length,
1612                lengths: vec![0; num_rows],
1613            };
1614        }
1615
1616        match self {
1617            LengthTracker::Variable { lengths, .. } => lengths,
1618            LengthTracker::Fixed { .. } => unreachable!(),
1619        }
1620    }
1621
1622    /// Initializes the offsets using the tracked lengths. Returns the sum of the
1623    /// lengths of the rows added.
1624    ///
1625    /// We initialize the offsets shifted down by one row index.
1626    ///
1627    /// As the rows are appended to the offsets will be incremented to match
1628    ///
1629    /// For example, consider the case of 3 rows of length 3, 4, and 6 respectively.
1630    /// The offsets would be initialized to `0, 0, 3, 7`
1631    ///
1632    /// Writing the first row entirely would yield `0, 3, 3, 7`
1633    /// The second, `0, 3, 7, 7`
1634    /// The third, `0, 3, 7, 13`
1635    //
1636    /// This would be the final offsets for reading
1637    //
1638    /// In this way offsets tracks the position during writing whilst eventually serving
1639    fn extend_offsets(&self, initial_offset: usize, offsets: &mut Vec<usize>) -> usize {
1640        match self {
1641            LengthTracker::Fixed { length, num_rows } => {
1642                offsets.extend((0..*num_rows).map(|i| initial_offset + i * length));
1643
1644                initial_offset + num_rows * length
1645            }
1646            LengthTracker::Variable {
1647                fixed_length,
1648                lengths,
1649            } => {
1650                let mut acc = initial_offset;
1651
1652                offsets.extend(lengths.iter().map(|length| {
1653                    let current = acc;
1654                    acc += length + fixed_length;
1655                    current
1656                }));
1657
1658                acc
1659            }
1660        }
1661    }
1662}
1663
1664/// Computes the length of each encoded [`Rows`] and returns an empty [`Rows`]
1665fn row_lengths(cols: &[ArrayRef], encoders: &[Encoder]) -> LengthTracker {
1666    use fixed::FixedLengthEncoding;
1667
1668    let num_rows = cols.first().map(|x| x.len()).unwrap_or(0);
1669    let mut tracker = LengthTracker::new(num_rows);
1670
1671    for (array, encoder) in cols.iter().zip(encoders) {
1672        match encoder {
1673            Encoder::Stateless => {
1674                downcast_primitive_array! {
1675                    array => tracker.push_fixed(fixed::encoded_len(array)),
1676                    DataType::Null => tracker.push_fixed(2)
1677                    DataType::Boolean => tracker.push_fixed(bool::ENCODED_LEN),
1678                    DataType::Binary => push_generic_byte_array_lengths(&mut tracker, as_generic_binary_array::<i32>(array)),
1679                    DataType::LargeBinary => push_generic_byte_array_lengths(&mut tracker, as_generic_binary_array::<i64>(array)),
1680                    DataType::BinaryView => push_byte_view_array_lengths(&mut tracker, array.as_binary_view()),
1681                    DataType::Utf8 => push_generic_byte_array_lengths(&mut tracker, array.as_string::<i32>()),
1682                    DataType::LargeUtf8 => push_generic_byte_array_lengths(&mut tracker, array.as_string::<i64>()),
1683                    DataType::Utf8View => push_byte_view_array_lengths(&mut tracker, array.as_string_view()),
1684                    DataType::FixedSizeBinary(len) => {
1685                        let len = len.to_usize().unwrap();
1686                        tracker.push_fixed(1 + len)
1687                    }
1688                    _ => unimplemented!("unsupported data type: {}", array.data_type()),
1689                }
1690            }
1691            Encoder::Dictionary(values, null) => {
1692                downcast_dictionary_array! {
1693                    array => {
1694                        tracker.push_variable(
1695                            array.keys().iter().map(|v| match v {
1696                                Some(k) => values.row_len(k.as_usize()),
1697                                None => null.data.len(),
1698                            })
1699                        )
1700                    }
1701                    _ => unreachable!(),
1702                }
1703            }
1704            Encoder::Struct(rows, null) => {
1705                let array = as_struct_array(array);
1706                if rows.num_rows() > 0 {
1707                    // Only calculate row length if there are rows
1708                    tracker.push_variable((0..array.len()).map(|idx| match array.is_valid(idx) {
1709                        true => 1 + rows.row_len(idx),
1710                        false => 1 + null.data.len(),
1711                    }));
1712                } else {
1713                    // Edge case for Struct([]) arrays (no child fields)
1714                    tracker.push_variable((0..array.len()).map(|idx| match array.is_valid(idx) {
1715                        true => 1,
1716                        false => 1 + null.data.len(),
1717                    }));
1718                }
1719            }
1720            Encoder::List(rows) => match array.data_type() {
1721                DataType::List(_) => {
1722                    list::compute_lengths(tracker.materialized(), rows, as_list_array(array))
1723                }
1724                DataType::LargeList(_) => {
1725                    list::compute_lengths(tracker.materialized(), rows, as_large_list_array(array))
1726                }
1727                DataType::ListView(_) => {
1728                    let list_view = array.as_list_view::<i32>();
1729                    let (min_offset, _) = compute_list_view_bounds(list_view);
1730                    list::compute_lengths_list_view(
1731                        tracker.materialized(),
1732                        rows,
1733                        list_view,
1734                        min_offset,
1735                    )
1736                }
1737                DataType::LargeListView(_) => {
1738                    let list_view = array.as_list_view::<i64>();
1739                    let (min_offset, _) = compute_list_view_bounds(list_view);
1740                    list::compute_lengths_list_view(
1741                        tracker.materialized(),
1742                        rows,
1743                        list_view,
1744                        min_offset,
1745                    )
1746                }
1747                DataType::FixedSizeList(_, _) => compute_lengths_fixed_size_list(
1748                    &mut tracker,
1749                    rows,
1750                    as_fixed_size_list_array(array),
1751                ),
1752                _ => unreachable!(),
1753            },
1754            Encoder::RunEndEncoded(rows) => match array.data_type() {
1755                DataType::RunEndEncoded(r, _) => match r.data_type() {
1756                    DataType::Int16 => run::compute_lengths(
1757                        tracker.materialized(),
1758                        rows,
1759                        array.as_run::<Int16Type>(),
1760                    ),
1761                    DataType::Int32 => run::compute_lengths(
1762                        tracker.materialized(),
1763                        rows,
1764                        array.as_run::<Int32Type>(),
1765                    ),
1766                    DataType::Int64 => run::compute_lengths(
1767                        tracker.materialized(),
1768                        rows,
1769                        array.as_run::<Int64Type>(),
1770                    ),
1771                    _ => unreachable!("Unsupported run end index type: {r:?}"),
1772                },
1773                _ => unreachable!(),
1774            },
1775            Encoder::Union {
1776                child_rows,
1777                field_to_type_ids,
1778                type_ids,
1779                offsets,
1780            } => {
1781                let union_array = array
1782                    .as_any()
1783                    .downcast_ref::<UnionArray>()
1784                    .expect("expected UnionArray");
1785
1786                let mut type_id_to_field_idx = [0usize; 128];
1787                for (field_idx, &type_id) in field_to_type_ids.iter().enumerate() {
1788                    type_id_to_field_idx[type_id as usize] = field_idx;
1789                }
1790
1791                let lengths = (0..union_array.len()).map(|i| {
1792                    let type_id = type_ids[i];
1793                    let field_idx = type_id_to_field_idx[type_id as usize];
1794                    let child_row_i = offsets.as_ref().map(|o| o[i] as usize).unwrap_or(i);
1795                    let child_row_len = child_rows[field_idx].row_len(child_row_i);
1796
1797                    // length: 1 byte type_id + child row bytes
1798                    1 + child_row_len
1799                });
1800
1801                tracker.push_variable(lengths);
1802            }
1803        }
1804    }
1805
1806    tracker
1807}
1808
1809/// Add to [`LengthTracker`] the encoded length of each item in the [`GenericByteArray`]
1810fn push_generic_byte_array_lengths<T: ByteArrayType>(
1811    tracker: &mut LengthTracker,
1812    array: &GenericByteArray<T>,
1813) {
1814    if let Some(nulls) = array.nulls().filter(|n| n.null_count() > 0) {
1815        tracker.push_variable(
1816            array
1817                .offsets()
1818                .lengths()
1819                .zip(nulls.iter())
1820                .map(|(length, is_valid)| if is_valid { Some(length) } else { None })
1821                .map(variable::padded_length),
1822        )
1823    } else {
1824        tracker.push_variable(
1825            array
1826                .offsets()
1827                .lengths()
1828                .map(variable::non_null_padded_length),
1829        )
1830    }
1831}
1832
1833/// Add to [`LengthTracker`] the encoded length of each item in the [`GenericByteViewArray`]
1834fn push_byte_view_array_lengths<T: ByteViewType>(
1835    tracker: &mut LengthTracker,
1836    array: &GenericByteViewArray<T>,
1837) {
1838    if let Some(nulls) = array.nulls().filter(|n| n.null_count() > 0) {
1839        tracker.push_variable(
1840            array
1841                .lengths()
1842                .zip(nulls.iter())
1843                .map(|(length, is_valid)| {
1844                    if is_valid {
1845                        Some(length as usize)
1846                    } else {
1847                        None
1848                    }
1849                })
1850                .map(variable::padded_length),
1851        )
1852    } else {
1853        tracker.push_variable(
1854            array
1855                .lengths()
1856                .map(|len| variable::padded_length(Some(len as usize))),
1857        )
1858    }
1859}
1860
1861/// Encodes a column to the provided [`Rows`] incrementing the offsets as it progresses
1862fn encode_column(
1863    data: &mut [u8],
1864    offsets: &mut [usize],
1865    column: &dyn Array,
1866    opts: SortOptions,
1867    encoder: &Encoder<'_>,
1868) {
1869    match encoder {
1870        Encoder::Stateless => {
1871            downcast_primitive_array! {
1872                column => {
1873                    if let Some(nulls) = column.nulls().filter(|n| n.null_count() > 0){
1874                        fixed::encode(data, offsets, column.values(), nulls, opts)
1875                    } else {
1876                        fixed::encode_not_null(data, offsets, column.values(), opts)
1877                    }
1878                }
1879                DataType::Null => {
1880                    for offset in offsets.iter_mut().skip(1) {
1881                        variable::encode_null_value(&mut data[*offset..], opts);
1882                        *offset += 2;
1883                    }
1884                }
1885                DataType::Boolean => {
1886                    if let Some(nulls) = column.nulls().filter(|n| n.null_count() > 0){
1887                        fixed::encode_boolean(data, offsets, column.as_boolean().values(), nulls, opts)
1888                    } else {
1889                        fixed::encode_boolean_not_null(data, offsets, column.as_boolean().values(), opts)
1890                    }
1891                }
1892                DataType::Binary => {
1893                    variable::encode_generic_byte_array(data, offsets, as_generic_binary_array::<i32>(column), opts)
1894                }
1895                DataType::BinaryView => {
1896                    variable::encode(data, offsets, column.as_binary_view().iter(), opts)
1897                }
1898                DataType::LargeBinary => {
1899                    variable::encode_generic_byte_array(data, offsets, as_generic_binary_array::<i64>(column), opts)
1900                }
1901                DataType::Utf8 => variable::encode_generic_byte_array(
1902                    data, offsets,
1903                    column.as_string::<i32>(),
1904                    opts,
1905                ),
1906                DataType::LargeUtf8 => variable::encode_generic_byte_array(
1907                    data, offsets,
1908                    column.as_string::<i64>(),
1909                    opts,
1910                ),
1911                DataType::Utf8View => variable::encode(
1912                    data, offsets,
1913                    column.as_string_view().iter().map(|x| x.map(|x| x.as_bytes())),
1914                    opts,
1915                ),
1916                DataType::FixedSizeBinary(_) => {
1917                    let array = column.as_any().downcast_ref().unwrap();
1918                    fixed::encode_fixed_size_binary(data, offsets, array, opts)
1919                }
1920                _ => unimplemented!("unsupported data type: {}", column.data_type()),
1921            }
1922        }
1923        Encoder::Dictionary(values, nulls) => {
1924            downcast_dictionary_array! {
1925                column => encode_dictionary_values(data, offsets, column, values, nulls),
1926                _ => unreachable!()
1927            }
1928        }
1929        Encoder::Struct(rows, null) => {
1930            fn struct_encode_helper<const NO_CHILD_FIELDS: bool>(
1931                array: &StructArray,
1932                offsets: &mut [usize],
1933                null_sentinel: u8,
1934                rows: &Rows,
1935                null: &Row<'_>,
1936                data: &mut [u8],
1937            ) {
1938                let empty_row = Row {
1939                    data: &[],
1940                    config: &rows.config,
1941                };
1942
1943                offsets
1944                    .iter_mut()
1945                    .skip(1)
1946                    .enumerate()
1947                    .for_each(|(idx, offset)| {
1948                        let (row, sentinel) = match array.is_valid(idx) {
1949                            true => (
1950                                if NO_CHILD_FIELDS {
1951                                    empty_row
1952                                } else {
1953                                    rows.row(idx)
1954                                },
1955                                0x01,
1956                            ),
1957                            false => (*null, null_sentinel),
1958                        };
1959                        let end_offset = *offset + 1 + row.as_ref().len();
1960                        data[*offset] = sentinel;
1961                        data[*offset + 1..end_offset].copy_from_slice(row.as_ref());
1962                        *offset = end_offset;
1963                    })
1964            }
1965
1966            let array = as_struct_array(column);
1967            let null_sentinel = null_sentinel(opts);
1968            if rows.num_rows() == 0 {
1969                // Edge case for Struct([]) arrays (no child fields)
1970                struct_encode_helper::<true>(array, offsets, null_sentinel, rows, null, data);
1971            } else {
1972                struct_encode_helper::<false>(array, offsets, null_sentinel, rows, null, data);
1973            }
1974        }
1975        Encoder::List(rows) => match column.data_type() {
1976            DataType::List(_) => list::encode(data, offsets, rows, opts, as_list_array(column)),
1977            DataType::LargeList(_) => {
1978                list::encode(data, offsets, rows, opts, as_large_list_array(column))
1979            }
1980            DataType::ListView(_) => {
1981                let list_view = column.as_list_view::<i32>();
1982                let (min_offset, _) = compute_list_view_bounds(list_view);
1983                list::encode_list_view(data, offsets, rows, opts, list_view, min_offset)
1984            }
1985            DataType::LargeListView(_) => {
1986                let list_view = column.as_list_view::<i64>();
1987                let (min_offset, _) = compute_list_view_bounds(list_view);
1988                list::encode_list_view(data, offsets, rows, opts, list_view, min_offset)
1989            }
1990            DataType::FixedSizeList(_, _) => {
1991                encode_fixed_size_list(data, offsets, rows, opts, as_fixed_size_list_array(column))
1992            }
1993            _ => unreachable!(),
1994        },
1995        Encoder::RunEndEncoded(rows) => match column.data_type() {
1996            DataType::RunEndEncoded(r, _) => match r.data_type() {
1997                DataType::Int16 => {
1998                    run::encode(data, offsets, rows, opts, column.as_run::<Int16Type>())
1999                }
2000                DataType::Int32 => {
2001                    run::encode(data, offsets, rows, opts, column.as_run::<Int32Type>())
2002                }
2003                DataType::Int64 => {
2004                    run::encode(data, offsets, rows, opts, column.as_run::<Int64Type>())
2005                }
2006                _ => unreachable!("Unsupported run end index type: {r:?}"),
2007            },
2008            _ => unreachable!(),
2009        },
2010        Encoder::Union {
2011            child_rows,
2012            field_to_type_ids,
2013            type_ids,
2014            offsets: offsets_buf,
2015        } => {
2016            let mut type_id_to_field_idx = [0usize; 128];
2017            for (field_idx, &type_id) in field_to_type_ids.iter().enumerate() {
2018                type_id_to_field_idx[type_id as usize] = field_idx;
2019            }
2020
2021            offsets
2022                .iter_mut()
2023                .skip(1)
2024                .enumerate()
2025                .for_each(|(i, offset)| {
2026                    let type_id = type_ids[i];
2027                    let field_idx = type_id_to_field_idx[type_id as usize];
2028
2029                    let child_row_idx = offsets_buf.as_ref().map(|o| o[i] as usize).unwrap_or(i);
2030                    let child_row = child_rows[field_idx].row(child_row_idx);
2031                    let child_bytes = child_row.as_ref();
2032
2033                    let type_id_byte = if opts.descending {
2034                        !(type_id as u8)
2035                    } else {
2036                        type_id as u8
2037                    };
2038                    data[*offset] = type_id_byte;
2039
2040                    let child_start = *offset + 1;
2041                    let child_end = child_start + child_bytes.len();
2042                    data[child_start..child_end].copy_from_slice(child_bytes);
2043
2044                    *offset = child_end;
2045                });
2046        }
2047    }
2048}
2049
2050/// Encode dictionary values not preserving the dictionary encoding
2051pub fn encode_dictionary_values<K: ArrowDictionaryKeyType>(
2052    data: &mut [u8],
2053    offsets: &mut [usize],
2054    column: &DictionaryArray<K>,
2055    values: &Rows,
2056    null: &Row<'_>,
2057) {
2058    for (offset, k) in offsets.iter_mut().skip(1).zip(column.keys()) {
2059        let row = match k {
2060            Some(k) => values.row(k.as_usize()).data,
2061            None => null.data,
2062        };
2063        let end_offset = *offset + row.len();
2064        data[*offset..end_offset].copy_from_slice(row);
2065        *offset = end_offset;
2066    }
2067}
2068
2069macro_rules! decode_primitive_helper {
2070    ($t:ty, $rows:ident, $data_type:ident, $options:ident) => {
2071        Arc::new(decode_primitive::<$t>($rows, $data_type, $options))
2072    };
2073}
2074
2075/// Decodes a the provided `field` from `rows`
2076///
2077/// # Safety
2078///
2079/// Rows must contain valid data for the provided field
2080unsafe fn decode_column(
2081    field: &SortField,
2082    rows: &mut [&[u8]],
2083    codec: &Codec,
2084    validate_utf8: bool,
2085) -> Result<ArrayRef, ArrowError> {
2086    let options = field.options;
2087
2088    let array: ArrayRef = match codec {
2089        Codec::Stateless => {
2090            let data_type = field.data_type.clone();
2091            downcast_primitive! {
2092                data_type => (decode_primitive_helper, rows, data_type, options),
2093                DataType::Null => {
2094                    variable::decode_null_value(rows, options);
2095                    Arc::new(NullArray::new(rows.len()))
2096                }
2097                DataType::Boolean => Arc::new(decode_bool(rows, options)),
2098                DataType::Binary => Arc::new(decode_binary::<i32>(rows, options)),
2099                DataType::LargeBinary => Arc::new(decode_binary::<i64>(rows, options)),
2100                DataType::BinaryView => Arc::new(decode_binary_view(rows, options)),
2101                DataType::FixedSizeBinary(size) => Arc::new(decode_fixed_size_binary(rows, size, options)),
2102                DataType::Utf8 => Arc::new(unsafe{ decode_string::<i32>(rows, options, validate_utf8) }),
2103                DataType::LargeUtf8 => Arc::new(unsafe { decode_string::<i64>(rows, options, validate_utf8) }),
2104                DataType::Utf8View => Arc::new(unsafe { decode_string_view(rows, options, validate_utf8) }),
2105                _ => return Err(ArrowError::NotYetImplemented(format!("unsupported data type: {data_type}" )))
2106            }
2107        }
2108        Codec::Dictionary(converter, _) => {
2109            let cols = unsafe { converter.convert_raw(rows, validate_utf8) }?;
2110            cols.into_iter().next().unwrap()
2111        }
2112        Codec::Struct(converter, _) => {
2113            let (null_count, nulls) = fixed::decode_nulls(rows);
2114            rows.iter_mut().for_each(|row| *row = &row[1..]);
2115            let children = unsafe { converter.convert_raw(rows, validate_utf8) }?;
2116
2117            let child_data: Vec<ArrayData> = children.iter().map(|c| c.to_data()).collect();
2118            // Since RowConverter flattens certain data types (i.e. Dictionary),
2119            // we need to use updated data type instead of original field
2120            let corrected_fields: Vec<Field> = match &field.data_type {
2121                DataType::Struct(struct_fields) => struct_fields
2122                    .iter()
2123                    .zip(child_data.iter())
2124                    .map(|(orig_field, child_array)| {
2125                        orig_field
2126                            .as_ref()
2127                            .clone()
2128                            .with_data_type(child_array.data_type().clone())
2129                    })
2130                    .collect(),
2131                _ => unreachable!("Only Struct types should be corrected here"),
2132            };
2133            let corrected_struct_type = DataType::Struct(corrected_fields.into());
2134            let builder = ArrayDataBuilder::new(corrected_struct_type)
2135                .len(rows.len())
2136                .null_count(null_count)
2137                .null_bit_buffer(Some(nulls))
2138                .child_data(child_data);
2139
2140            Arc::new(StructArray::from(unsafe { builder.build_unchecked() }))
2141        }
2142        Codec::List(converter) => match &field.data_type {
2143            DataType::List(_) => {
2144                Arc::new(unsafe { list::decode::<i32>(converter, rows, field, validate_utf8) }?)
2145            }
2146            DataType::LargeList(_) => {
2147                Arc::new(unsafe { list::decode::<i64>(converter, rows, field, validate_utf8) }?)
2148            }
2149            DataType::ListView(_) => Arc::new(unsafe {
2150                list::decode_list_view::<i32>(converter, rows, field, validate_utf8)
2151            }?),
2152            DataType::LargeListView(_) => Arc::new(unsafe {
2153                list::decode_list_view::<i64>(converter, rows, field, validate_utf8)
2154            }?),
2155            DataType::FixedSizeList(_, value_length) => Arc::new(unsafe {
2156                list::decode_fixed_size_list(
2157                    converter,
2158                    rows,
2159                    field,
2160                    validate_utf8,
2161                    value_length.as_usize(),
2162                )
2163            }?),
2164            _ => unreachable!(),
2165        },
2166        Codec::RunEndEncoded(converter) => match &field.data_type {
2167            DataType::RunEndEncoded(run_ends, _) => match run_ends.data_type() {
2168                DataType::Int16 => Arc::new(unsafe {
2169                    run::decode::<Int16Type>(converter, rows, field, validate_utf8)
2170                }?),
2171                DataType::Int32 => Arc::new(unsafe {
2172                    run::decode::<Int32Type>(converter, rows, field, validate_utf8)
2173                }?),
2174                DataType::Int64 => Arc::new(unsafe {
2175                    run::decode::<Int64Type>(converter, rows, field, validate_utf8)
2176                }?),
2177                _ => unreachable!(),
2178            },
2179            _ => unreachable!(),
2180        },
2181        Codec::Union(converters, field_to_type_ids, null_rows) => {
2182            let len = rows.len();
2183
2184            let DataType::Union(union_fields, mode) = &field.data_type else {
2185                unreachable!()
2186            };
2187
2188            let mut type_id_to_field_idx = [0usize; 128];
2189            for (field_idx, &type_id) in field_to_type_ids.iter().enumerate() {
2190                type_id_to_field_idx[type_id as usize] = field_idx;
2191            }
2192
2193            let mut type_ids = Vec::with_capacity(len);
2194            let mut rows_by_field: Vec<Vec<(usize, &[u8])>> = vec![Vec::new(); converters.len()];
2195
2196            for (idx, row) in rows.iter_mut().enumerate() {
2197                let type_id_byte = {
2198                    let id = row[0];
2199                    if options.descending { !id } else { id }
2200                };
2201
2202                let type_id = type_id_byte as i8;
2203                type_ids.push(type_id);
2204
2205                let field_idx = type_id_to_field_idx[type_id as usize];
2206
2207                let child_row = &row[1..];
2208                rows_by_field[field_idx].push((idx, child_row));
2209            }
2210
2211            let mut child_arrays: Vec<ArrayRef> = Vec::with_capacity(converters.len());
2212            let mut offsets = (*mode == UnionMode::Dense).then(|| Vec::with_capacity(len));
2213
2214            for (field_idx, converter) in converters.iter().enumerate() {
2215                let field_rows = &rows_by_field[field_idx];
2216
2217                match &mode {
2218                    UnionMode::Dense => {
2219                        if field_rows.is_empty() {
2220                            let (_, field) = union_fields.iter().nth(field_idx).unwrap();
2221                            child_arrays.push(arrow_array::new_empty_array(field.data_type()));
2222                            continue;
2223                        }
2224
2225                        let mut child_data = field_rows
2226                            .iter()
2227                            .map(|(_, bytes)| *bytes)
2228                            .collect::<Vec<_>>();
2229
2230                        let child_array =
2231                            unsafe { converter.convert_raw(&mut child_data, validate_utf8) }?;
2232
2233                        // advance row slices by the bytes consumed
2234                        for ((row_idx, original_bytes), remaining_bytes) in
2235                            field_rows.iter().zip(child_data)
2236                        {
2237                            let consumed_length = 1 + original_bytes.len() - remaining_bytes.len();
2238                            rows[*row_idx] = &rows[*row_idx][consumed_length..];
2239                        }
2240
2241                        child_arrays.push(child_array.into_iter().next().unwrap());
2242                    }
2243                    UnionMode::Sparse => {
2244                        let mut sparse_data: Vec<&[u8]> = Vec::with_capacity(len);
2245                        let mut field_row_iter = field_rows.iter().peekable();
2246                        let null_row_bytes: &[u8] = &null_rows[field_idx].data;
2247
2248                        for idx in 0..len {
2249                            if let Some((next_idx, bytes)) = field_row_iter.peek() {
2250                                if *next_idx == idx {
2251                                    sparse_data.push(*bytes);
2252
2253                                    field_row_iter.next();
2254                                    continue;
2255                                }
2256                            }
2257                            sparse_data.push(null_row_bytes);
2258                        }
2259
2260                        let child_array =
2261                            unsafe { converter.convert_raw(&mut sparse_data, validate_utf8) }?;
2262
2263                        // advance row slices by the bytes consumed for rows that belong to this field
2264                        for (row_idx, child_row) in field_rows.iter() {
2265                            let remaining_len = sparse_data[*row_idx].len();
2266                            let consumed_length = 1 + child_row.len() - remaining_len;
2267                            rows[*row_idx] = &rows[*row_idx][consumed_length..];
2268                        }
2269
2270                        child_arrays.push(child_array.into_iter().next().unwrap());
2271                    }
2272                }
2273            }
2274
2275            // build offsets for dense unions
2276            if let Some(ref mut offsets_vec) = offsets {
2277                let mut count = vec![0i32; converters.len()];
2278                for type_id in &type_ids {
2279                    let field_idx = *type_id as usize;
2280                    offsets_vec.push(count[field_idx]);
2281
2282                    count[field_idx] += 1;
2283                }
2284            }
2285
2286            let type_ids_buffer = ScalarBuffer::from(type_ids);
2287            let offsets_buffer = offsets.map(ScalarBuffer::from);
2288
2289            let union_array = UnionArray::try_new(
2290                union_fields.clone(),
2291                type_ids_buffer,
2292                offsets_buffer,
2293                child_arrays,
2294            )?;
2295
2296            // note: union arrays don't support physical null buffers
2297            // nulls are represented logically though child arrays
2298            Arc::new(union_array)
2299        }
2300    };
2301    Ok(array)
2302}
2303
2304#[cfg(test)]
2305mod tests {
2306    use arrow_array::builder::*;
2307    use arrow_array::types::*;
2308    use arrow_array::*;
2309    use arrow_buffer::{Buffer, OffsetBuffer};
2310    use arrow_buffer::{NullBuffer, i256};
2311    use arrow_cast::display::{ArrayFormatter, FormatOptions};
2312    use arrow_ord::sort::{LexicographicalComparator, SortColumn};
2313    use rand::distr::uniform::SampleUniform;
2314    use rand::distr::{Distribution, StandardUniform};
2315    use rand::prelude::StdRng;
2316    use rand::{Rng, RngCore, SeedableRng};
2317
2318    use super::*;
2319
2320    #[test]
2321    fn test_fixed_width() {
2322        let cols = [
2323            Arc::new(Int16Array::from_iter([
2324                Some(1),
2325                Some(2),
2326                None,
2327                Some(-5),
2328                Some(2),
2329                Some(2),
2330                Some(0),
2331            ])) as ArrayRef,
2332            Arc::new(Float32Array::from_iter([
2333                Some(1.3),
2334                Some(2.5),
2335                None,
2336                Some(4.),
2337                Some(0.1),
2338                Some(-4.),
2339                Some(-0.),
2340            ])) as ArrayRef,
2341        ];
2342
2343        let converter = RowConverter::new(vec![
2344            SortField::new(DataType::Int16),
2345            SortField::new(DataType::Float32),
2346        ])
2347        .unwrap();
2348        let rows = converter.convert_columns(&cols).unwrap();
2349
2350        assert_eq!(rows.offsets, &[0, 8, 16, 24, 32, 40, 48, 56]);
2351        assert_eq!(
2352            rows.buffer,
2353            &[
2354                1, 128, 1, //
2355                1, 191, 166, 102, 102, //
2356                1, 128, 2, //
2357                1, 192, 32, 0, 0, //
2358                0, 0, 0, //
2359                0, 0, 0, 0, 0, //
2360                1, 127, 251, //
2361                1, 192, 128, 0, 0, //
2362                1, 128, 2, //
2363                1, 189, 204, 204, 205, //
2364                1, 128, 2, //
2365                1, 63, 127, 255, 255, //
2366                1, 128, 0, //
2367                1, 127, 255, 255, 255 //
2368            ]
2369        );
2370
2371        assert!(rows.row(3) < rows.row(6));
2372        assert!(rows.row(0) < rows.row(1));
2373        assert!(rows.row(3) < rows.row(0));
2374        assert!(rows.row(4) < rows.row(1));
2375        assert!(rows.row(5) < rows.row(4));
2376
2377        let back = converter.convert_rows(&rows).unwrap();
2378        for (expected, actual) in cols.iter().zip(&back) {
2379            assert_eq!(expected, actual);
2380        }
2381    }
2382
2383    #[test]
2384    fn test_decimal32() {
2385        let converter = RowConverter::new(vec![SortField::new(DataType::Decimal32(
2386            DECIMAL32_MAX_PRECISION,
2387            7,
2388        ))])
2389        .unwrap();
2390        let col = Arc::new(
2391            Decimal32Array::from_iter([
2392                None,
2393                Some(i32::MIN),
2394                Some(-13),
2395                Some(46_i32),
2396                Some(5456_i32),
2397                Some(i32::MAX),
2398            ])
2399            .with_precision_and_scale(9, 7)
2400            .unwrap(),
2401        ) as ArrayRef;
2402
2403        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2404        for i in 0..rows.num_rows() - 1 {
2405            assert!(rows.row(i) < rows.row(i + 1));
2406        }
2407
2408        let back = converter.convert_rows(&rows).unwrap();
2409        assert_eq!(back.len(), 1);
2410        assert_eq!(col.as_ref(), back[0].as_ref())
2411    }
2412
2413    #[test]
2414    fn test_decimal64() {
2415        let converter = RowConverter::new(vec![SortField::new(DataType::Decimal64(
2416            DECIMAL64_MAX_PRECISION,
2417            7,
2418        ))])
2419        .unwrap();
2420        let col = Arc::new(
2421            Decimal64Array::from_iter([
2422                None,
2423                Some(i64::MIN),
2424                Some(-13),
2425                Some(46_i64),
2426                Some(5456_i64),
2427                Some(i64::MAX),
2428            ])
2429            .with_precision_and_scale(18, 7)
2430            .unwrap(),
2431        ) as ArrayRef;
2432
2433        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2434        for i in 0..rows.num_rows() - 1 {
2435            assert!(rows.row(i) < rows.row(i + 1));
2436        }
2437
2438        let back = converter.convert_rows(&rows).unwrap();
2439        assert_eq!(back.len(), 1);
2440        assert_eq!(col.as_ref(), back[0].as_ref())
2441    }
2442
2443    #[test]
2444    fn test_decimal128() {
2445        let converter = RowConverter::new(vec![SortField::new(DataType::Decimal128(
2446            DECIMAL128_MAX_PRECISION,
2447            7,
2448        ))])
2449        .unwrap();
2450        let col = Arc::new(
2451            Decimal128Array::from_iter([
2452                None,
2453                Some(i128::MIN),
2454                Some(-13),
2455                Some(46_i128),
2456                Some(5456_i128),
2457                Some(i128::MAX),
2458            ])
2459            .with_precision_and_scale(38, 7)
2460            .unwrap(),
2461        ) as ArrayRef;
2462
2463        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2464        for i in 0..rows.num_rows() - 1 {
2465            assert!(rows.row(i) < rows.row(i + 1));
2466        }
2467
2468        let back = converter.convert_rows(&rows).unwrap();
2469        assert_eq!(back.len(), 1);
2470        assert_eq!(col.as_ref(), back[0].as_ref())
2471    }
2472
2473    #[test]
2474    fn test_decimal256() {
2475        let converter = RowConverter::new(vec![SortField::new(DataType::Decimal256(
2476            DECIMAL256_MAX_PRECISION,
2477            7,
2478        ))])
2479        .unwrap();
2480        let col = Arc::new(
2481            Decimal256Array::from_iter([
2482                None,
2483                Some(i256::MIN),
2484                Some(i256::from_parts(0, -1)),
2485                Some(i256::from_parts(u128::MAX, -1)),
2486                Some(i256::from_parts(u128::MAX, 0)),
2487                Some(i256::from_parts(0, 46_i128)),
2488                Some(i256::from_parts(5, 46_i128)),
2489                Some(i256::MAX),
2490            ])
2491            .with_precision_and_scale(DECIMAL256_MAX_PRECISION, 7)
2492            .unwrap(),
2493        ) as ArrayRef;
2494
2495        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2496        for i in 0..rows.num_rows() - 1 {
2497            assert!(rows.row(i) < rows.row(i + 1));
2498        }
2499
2500        let back = converter.convert_rows(&rows).unwrap();
2501        assert_eq!(back.len(), 1);
2502        assert_eq!(col.as_ref(), back[0].as_ref())
2503    }
2504
2505    #[test]
2506    fn test_bool() {
2507        let converter = RowConverter::new(vec![SortField::new(DataType::Boolean)]).unwrap();
2508
2509        let col = Arc::new(BooleanArray::from_iter([None, Some(false), Some(true)])) as ArrayRef;
2510
2511        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2512        assert!(rows.row(2) > rows.row(1));
2513        assert!(rows.row(2) > rows.row(0));
2514        assert!(rows.row(1) > rows.row(0));
2515
2516        let cols = converter.convert_rows(&rows).unwrap();
2517        assert_eq!(&cols[0], &col);
2518
2519        let converter = RowConverter::new(vec![SortField::new_with_options(
2520            DataType::Boolean,
2521            SortOptions::default().desc().with_nulls_first(false),
2522        )])
2523        .unwrap();
2524
2525        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2526        assert!(rows.row(2) < rows.row(1));
2527        assert!(rows.row(2) < rows.row(0));
2528        assert!(rows.row(1) < rows.row(0));
2529        let cols = converter.convert_rows(&rows).unwrap();
2530        assert_eq!(&cols[0], &col);
2531    }
2532
2533    #[test]
2534    fn test_timezone() {
2535        let a =
2536            TimestampNanosecondArray::from(vec![1, 2, 3, 4, 5]).with_timezone("+01:00".to_string());
2537        let d = a.data_type().clone();
2538
2539        let converter = RowConverter::new(vec![SortField::new(a.data_type().clone())]).unwrap();
2540        let rows = converter.convert_columns(&[Arc::new(a) as _]).unwrap();
2541        let back = converter.convert_rows(&rows).unwrap();
2542        assert_eq!(back.len(), 1);
2543        assert_eq!(back[0].data_type(), &d);
2544
2545        // Test dictionary
2546        let mut a = PrimitiveDictionaryBuilder::<Int32Type, TimestampNanosecondType>::new();
2547        a.append(34).unwrap();
2548        a.append_null();
2549        a.append(345).unwrap();
2550
2551        // Construct dictionary with a timezone
2552        let dict = a.finish();
2553        let values = TimestampNanosecondArray::from(dict.values().to_data());
2554        let dict_with_tz = dict.with_values(Arc::new(values.with_timezone("+02:00")));
2555        let v = DataType::Timestamp(TimeUnit::Nanosecond, Some("+02:00".into()));
2556        let d = DataType::Dictionary(Box::new(DataType::Int32), Box::new(v.clone()));
2557
2558        assert_eq!(dict_with_tz.data_type(), &d);
2559        let converter = RowConverter::new(vec![SortField::new(d.clone())]).unwrap();
2560        let rows = converter
2561            .convert_columns(&[Arc::new(dict_with_tz) as _])
2562            .unwrap();
2563        let back = converter.convert_rows(&rows).unwrap();
2564        assert_eq!(back.len(), 1);
2565        assert_eq!(back[0].data_type(), &v);
2566    }
2567
2568    #[test]
2569    fn test_null_encoding() {
2570        let col = Arc::new(NullArray::new(10));
2571        let converter = RowConverter::new(vec![SortField::new(DataType::Null)]).unwrap();
2572        let rows = converter.convert_columns(&[col]).unwrap();
2573        assert_eq!(rows.num_rows(), 10);
2574        // NULL element encoded as 2 bytes data
2575        assert_eq!(rows.row(1).data.len(), 2);
2576    }
2577
2578    #[test]
2579    fn test_variable_width() {
2580        let col = Arc::new(StringArray::from_iter([
2581            Some("hello"),
2582            Some("he"),
2583            None,
2584            Some("foo"),
2585            Some(""),
2586        ])) as ArrayRef;
2587
2588        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
2589        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2590
2591        assert!(rows.row(1) < rows.row(0));
2592        assert!(rows.row(2) < rows.row(4));
2593        assert!(rows.row(3) < rows.row(0));
2594        assert!(rows.row(3) < rows.row(1));
2595
2596        let cols = converter.convert_rows(&rows).unwrap();
2597        assert_eq!(&cols[0], &col);
2598
2599        let col = Arc::new(BinaryArray::from_iter([
2600            None,
2601            Some(vec![0_u8; 0]),
2602            Some(vec![0_u8; 6]),
2603            Some(vec![0_u8; variable::MINI_BLOCK_SIZE]),
2604            Some(vec![0_u8; variable::MINI_BLOCK_SIZE + 1]),
2605            Some(vec![0_u8; variable::BLOCK_SIZE]),
2606            Some(vec![0_u8; variable::BLOCK_SIZE + 1]),
2607            Some(vec![1_u8; 6]),
2608            Some(vec![1_u8; variable::MINI_BLOCK_SIZE]),
2609            Some(vec![1_u8; variable::MINI_BLOCK_SIZE + 1]),
2610            Some(vec![1_u8; variable::BLOCK_SIZE]),
2611            Some(vec![1_u8; variable::BLOCK_SIZE + 1]),
2612            Some(vec![0xFF_u8; 6]),
2613            Some(vec![0xFF_u8; variable::MINI_BLOCK_SIZE]),
2614            Some(vec![0xFF_u8; variable::MINI_BLOCK_SIZE + 1]),
2615            Some(vec![0xFF_u8; variable::BLOCK_SIZE]),
2616            Some(vec![0xFF_u8; variable::BLOCK_SIZE + 1]),
2617        ])) as ArrayRef;
2618
2619        let converter = RowConverter::new(vec![SortField::new(DataType::Binary)]).unwrap();
2620        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2621
2622        for i in 0..rows.num_rows() {
2623            for j in i + 1..rows.num_rows() {
2624                assert!(
2625                    rows.row(i) < rows.row(j),
2626                    "{} < {} - {:?} < {:?}",
2627                    i,
2628                    j,
2629                    rows.row(i),
2630                    rows.row(j)
2631                );
2632            }
2633        }
2634
2635        let cols = converter.convert_rows(&rows).unwrap();
2636        assert_eq!(&cols[0], &col);
2637
2638        let converter = RowConverter::new(vec![SortField::new_with_options(
2639            DataType::Binary,
2640            SortOptions::default().desc().with_nulls_first(false),
2641        )])
2642        .unwrap();
2643        let rows = converter.convert_columns(&[Arc::clone(&col)]).unwrap();
2644
2645        for i in 0..rows.num_rows() {
2646            for j in i + 1..rows.num_rows() {
2647                assert!(
2648                    rows.row(i) > rows.row(j),
2649                    "{} > {} - {:?} > {:?}",
2650                    i,
2651                    j,
2652                    rows.row(i),
2653                    rows.row(j)
2654                );
2655            }
2656        }
2657
2658        let cols = converter.convert_rows(&rows).unwrap();
2659        assert_eq!(&cols[0], &col);
2660    }
2661
2662    /// If `exact` is false performs a logical comparison between a and dictionary-encoded b
2663    fn dictionary_eq(a: &dyn Array, b: &dyn Array) {
2664        match b.data_type() {
2665            DataType::Dictionary(_, v) => {
2666                assert_eq!(a.data_type(), v.as_ref());
2667                let b = arrow_cast::cast(b, v).unwrap();
2668                assert_eq!(a, b.as_ref())
2669            }
2670            _ => assert_eq!(a, b),
2671        }
2672    }
2673
2674    #[test]
2675    fn test_string_dictionary() {
2676        let a = Arc::new(DictionaryArray::<Int32Type>::from_iter([
2677            Some("foo"),
2678            Some("hello"),
2679            Some("he"),
2680            None,
2681            Some("hello"),
2682            Some(""),
2683            Some("hello"),
2684            Some("hello"),
2685        ])) as ArrayRef;
2686
2687        let field = SortField::new(a.data_type().clone());
2688        let converter = RowConverter::new(vec![field]).unwrap();
2689        let rows_a = converter.convert_columns(&[Arc::clone(&a)]).unwrap();
2690
2691        assert!(rows_a.row(3) < rows_a.row(5));
2692        assert!(rows_a.row(2) < rows_a.row(1));
2693        assert!(rows_a.row(0) < rows_a.row(1));
2694        assert!(rows_a.row(3) < rows_a.row(0));
2695
2696        assert_eq!(rows_a.row(1), rows_a.row(4));
2697        assert_eq!(rows_a.row(1), rows_a.row(6));
2698        assert_eq!(rows_a.row(1), rows_a.row(7));
2699
2700        let cols = converter.convert_rows(&rows_a).unwrap();
2701        dictionary_eq(&cols[0], &a);
2702
2703        let b = Arc::new(DictionaryArray::<Int32Type>::from_iter([
2704            Some("hello"),
2705            None,
2706            Some("cupcakes"),
2707        ])) as ArrayRef;
2708
2709        let rows_b = converter.convert_columns(&[Arc::clone(&b)]).unwrap();
2710        assert_eq!(rows_a.row(1), rows_b.row(0));
2711        assert_eq!(rows_a.row(3), rows_b.row(1));
2712        assert!(rows_b.row(2) < rows_a.row(0));
2713
2714        let cols = converter.convert_rows(&rows_b).unwrap();
2715        dictionary_eq(&cols[0], &b);
2716
2717        let converter = RowConverter::new(vec![SortField::new_with_options(
2718            a.data_type().clone(),
2719            SortOptions::default().desc().with_nulls_first(false),
2720        )])
2721        .unwrap();
2722
2723        let rows_c = converter.convert_columns(&[Arc::clone(&a)]).unwrap();
2724        assert!(rows_c.row(3) > rows_c.row(5));
2725        assert!(rows_c.row(2) > rows_c.row(1));
2726        assert!(rows_c.row(0) > rows_c.row(1));
2727        assert!(rows_c.row(3) > rows_c.row(0));
2728
2729        let cols = converter.convert_rows(&rows_c).unwrap();
2730        dictionary_eq(&cols[0], &a);
2731
2732        let converter = RowConverter::new(vec![SortField::new_with_options(
2733            a.data_type().clone(),
2734            SortOptions::default().desc().with_nulls_first(true),
2735        )])
2736        .unwrap();
2737
2738        let rows_c = converter.convert_columns(&[Arc::clone(&a)]).unwrap();
2739        assert!(rows_c.row(3) < rows_c.row(5));
2740        assert!(rows_c.row(2) > rows_c.row(1));
2741        assert!(rows_c.row(0) > rows_c.row(1));
2742        assert!(rows_c.row(3) < rows_c.row(0));
2743
2744        let cols = converter.convert_rows(&rows_c).unwrap();
2745        dictionary_eq(&cols[0], &a);
2746    }
2747
2748    #[test]
2749    fn test_struct() {
2750        // Test basic
2751        let a = Arc::new(Int32Array::from(vec![1, 1, 2, 2])) as ArrayRef;
2752        let a_f = Arc::new(Field::new("int", DataType::Int32, false));
2753        let u = Arc::new(StringArray::from(vec!["a", "b", "c", "d"])) as ArrayRef;
2754        let u_f = Arc::new(Field::new("s", DataType::Utf8, false));
2755        let s1 = Arc::new(StructArray::from(vec![(a_f, a), (u_f, u)])) as ArrayRef;
2756
2757        let sort_fields = vec![SortField::new(s1.data_type().clone())];
2758        let converter = RowConverter::new(sort_fields).unwrap();
2759        let r1 = converter.convert_columns(&[Arc::clone(&s1)]).unwrap();
2760
2761        for (a, b) in r1.iter().zip(r1.iter().skip(1)) {
2762            assert!(a < b);
2763        }
2764
2765        let back = converter.convert_rows(&r1).unwrap();
2766        assert_eq!(back.len(), 1);
2767        assert_eq!(&back[0], &s1);
2768
2769        // Test struct nullability
2770        let data = s1
2771            .to_data()
2772            .into_builder()
2773            .null_bit_buffer(Some(Buffer::from_slice_ref([0b00001010])))
2774            .null_count(2)
2775            .build()
2776            .unwrap();
2777
2778        let s2 = Arc::new(StructArray::from(data)) as ArrayRef;
2779        let r2 = converter.convert_columns(&[Arc::clone(&s2)]).unwrap();
2780        assert_eq!(r2.row(0), r2.row(2)); // Nulls equal
2781        assert!(r2.row(0) < r2.row(1)); // Nulls first
2782        assert_ne!(r1.row(0), r2.row(0)); // Value does not equal null
2783        assert_eq!(r1.row(1), r2.row(1)); // Values equal
2784
2785        let back = converter.convert_rows(&r2).unwrap();
2786        assert_eq!(back.len(), 1);
2787        assert_eq!(&back[0], &s2);
2788
2789        back[0].to_data().validate_full().unwrap();
2790    }
2791
2792    #[test]
2793    fn test_dictionary_in_struct() {
2794        let builder = StringDictionaryBuilder::<Int32Type>::new();
2795        let mut struct_builder = StructBuilder::new(
2796            vec![Field::new_dictionary(
2797                "foo",
2798                DataType::Int32,
2799                DataType::Utf8,
2800                true,
2801            )],
2802            vec![Box::new(builder)],
2803        );
2804
2805        let dict_builder = struct_builder
2806            .field_builder::<StringDictionaryBuilder<Int32Type>>(0)
2807            .unwrap();
2808
2809        // Flattened: ["a", null, "a", "b"]
2810        dict_builder.append_value("a");
2811        dict_builder.append_null();
2812        dict_builder.append_value("a");
2813        dict_builder.append_value("b");
2814
2815        for _ in 0..4 {
2816            struct_builder.append(true);
2817        }
2818
2819        let s = Arc::new(struct_builder.finish()) as ArrayRef;
2820        let sort_fields = vec![SortField::new(s.data_type().clone())];
2821        let converter = RowConverter::new(sort_fields).unwrap();
2822        let r = converter.convert_columns(&[Arc::clone(&s)]).unwrap();
2823
2824        let back = converter.convert_rows(&r).unwrap();
2825        let [s2] = back.try_into().unwrap();
2826
2827        // RowConverter flattens Dictionary
2828        // s.ty = Struct("foo": Dictionary(Int32, Utf8)), s2.ty = Struct("foo": Utf8)
2829        assert_ne!(&s.data_type(), &s2.data_type());
2830        s2.to_data().validate_full().unwrap();
2831
2832        // Check if the logical data remains the same
2833        // Keys: [0, null, 0, 1]
2834        // Values: ["a", "b"]
2835        let s1_struct = s.as_struct();
2836        let s1_0 = s1_struct.column(0);
2837        let s1_idx_0 = s1_0.as_dictionary::<Int32Type>();
2838        let keys = s1_idx_0.keys();
2839        let values = s1_idx_0.values().as_string::<i32>();
2840        // Flattened: ["a", null, "a", "b"]
2841        let s2_struct = s2.as_struct();
2842        let s2_0 = s2_struct.column(0);
2843        let s2_idx_0 = s2_0.as_string::<i32>();
2844
2845        for i in 0..keys.len() {
2846            if keys.is_null(i) {
2847                assert!(s2_idx_0.is_null(i));
2848            } else {
2849                let dict_index = keys.value(i) as usize;
2850                assert_eq!(values.value(dict_index), s2_idx_0.value(i));
2851            }
2852        }
2853    }
2854
2855    #[test]
2856    fn test_dictionary_in_struct_empty() {
2857        let ty = DataType::Struct(
2858            vec![Field::new_dictionary(
2859                "foo",
2860                DataType::Int32,
2861                DataType::Int32,
2862                false,
2863            )]
2864            .into(),
2865        );
2866        let s = arrow_array::new_empty_array(&ty);
2867
2868        let sort_fields = vec![SortField::new(s.data_type().clone())];
2869        let converter = RowConverter::new(sort_fields).unwrap();
2870        let r = converter.convert_columns(&[Arc::clone(&s)]).unwrap();
2871
2872        let back = converter.convert_rows(&r).unwrap();
2873        let [s2] = back.try_into().unwrap();
2874
2875        // RowConverter flattens Dictionary
2876        // s.ty = Struct("foo": Dictionary(Int32, Int32)), s2.ty = Struct("foo": Int32)
2877        assert_ne!(&s.data_type(), &s2.data_type());
2878        s2.to_data().validate_full().unwrap();
2879        assert_eq!(s.len(), 0);
2880        assert_eq!(s2.len(), 0);
2881    }
2882
2883    #[test]
2884    fn test_list_of_string_dictionary() {
2885        let mut builder = ListBuilder::<StringDictionaryBuilder<Int32Type>>::default();
2886        // List[0] = ["a", "b", "zero", null, "c", "b", "d" (dict)]
2887        builder.values().append("a").unwrap();
2888        builder.values().append("b").unwrap();
2889        builder.values().append("zero").unwrap();
2890        builder.values().append_null();
2891        builder.values().append("c").unwrap();
2892        builder.values().append("b").unwrap();
2893        builder.values().append("d").unwrap();
2894        builder.append(true);
2895        // List[1] = null
2896        builder.append(false);
2897        // List[2] = ["e", "zero", "a" (dict)]
2898        builder.values().append("e").unwrap();
2899        builder.values().append("zero").unwrap();
2900        builder.values().append("a").unwrap();
2901        builder.append(true);
2902
2903        let a = Arc::new(builder.finish()) as ArrayRef;
2904        let data_type = a.data_type().clone();
2905
2906        let field = SortField::new(data_type.clone());
2907        let converter = RowConverter::new(vec![field]).unwrap();
2908        let rows = converter.convert_columns(&[Arc::clone(&a)]).unwrap();
2909
2910        let back = converter.convert_rows(&rows).unwrap();
2911        assert_eq!(back.len(), 1);
2912        let [a2] = back.try_into().unwrap();
2913
2914        // RowConverter flattens Dictionary
2915        // a.ty: List(Dictionary(Int32, Utf8)), a2.ty: List(Utf8)
2916        assert_ne!(&a.data_type(), &a2.data_type());
2917
2918        a2.to_data().validate_full().unwrap();
2919
2920        let a2_list = a2.as_list::<i32>();
2921        let a1_list = a.as_list::<i32>();
2922
2923        // Check if the logical data remains the same
2924        // List[0] = ["a", "b", "zero", null, "c", "b", "d" (dict)]
2925        let a1_0 = a1_list.value(0);
2926        let a1_idx_0 = a1_0.as_dictionary::<Int32Type>();
2927        let keys = a1_idx_0.keys();
2928        let values = a1_idx_0.values().as_string::<i32>();
2929        let a2_0 = a2_list.value(0);
2930        let a2_idx_0 = a2_0.as_string::<i32>();
2931
2932        for i in 0..keys.len() {
2933            if keys.is_null(i) {
2934                assert!(a2_idx_0.is_null(i));
2935            } else {
2936                let dict_index = keys.value(i) as usize;
2937                assert_eq!(values.value(dict_index), a2_idx_0.value(i));
2938            }
2939        }
2940
2941        // List[1] = null
2942        assert!(a1_list.is_null(1));
2943        assert!(a2_list.is_null(1));
2944
2945        // List[2] = ["e", "zero", "a" (dict)]
2946        let a1_2 = a1_list.value(2);
2947        let a1_idx_2 = a1_2.as_dictionary::<Int32Type>();
2948        let keys = a1_idx_2.keys();
2949        let values = a1_idx_2.values().as_string::<i32>();
2950        let a2_2 = a2_list.value(2);
2951        let a2_idx_2 = a2_2.as_string::<i32>();
2952
2953        for i in 0..keys.len() {
2954            if keys.is_null(i) {
2955                assert!(a2_idx_2.is_null(i));
2956            } else {
2957                let dict_index = keys.value(i) as usize;
2958                assert_eq!(values.value(dict_index), a2_idx_2.value(i));
2959            }
2960        }
2961    }
2962
2963    #[test]
2964    fn test_primitive_dictionary() {
2965        let mut builder = PrimitiveDictionaryBuilder::<Int32Type, Int32Type>::new();
2966        builder.append(2).unwrap();
2967        builder.append(3).unwrap();
2968        builder.append(0).unwrap();
2969        builder.append_null();
2970        builder.append(5).unwrap();
2971        builder.append(3).unwrap();
2972        builder.append(-1).unwrap();
2973
2974        let a = builder.finish();
2975        let data_type = a.data_type().clone();
2976        let columns = [Arc::new(a) as ArrayRef];
2977
2978        let field = SortField::new(data_type.clone());
2979        let converter = RowConverter::new(vec![field]).unwrap();
2980        let rows = converter.convert_columns(&columns).unwrap();
2981        assert!(rows.row(0) < rows.row(1));
2982        assert!(rows.row(2) < rows.row(0));
2983        assert!(rows.row(3) < rows.row(2));
2984        assert!(rows.row(6) < rows.row(2));
2985        assert!(rows.row(3) < rows.row(6));
2986
2987        let back = converter.convert_rows(&rows).unwrap();
2988        assert_eq!(back.len(), 1);
2989        back[0].to_data().validate_full().unwrap();
2990    }
2991
2992    #[test]
2993    fn test_dictionary_nulls() {
2994        let values = Int32Array::from_iter([Some(1), Some(-1), None, Some(4), None]).into_data();
2995        let keys =
2996            Int32Array::from_iter([Some(0), Some(0), Some(1), Some(2), Some(4), None]).into_data();
2997
2998        let data_type = DataType::Dictionary(Box::new(DataType::Int32), Box::new(DataType::Int32));
2999        let data = keys
3000            .into_builder()
3001            .data_type(data_type.clone())
3002            .child_data(vec![values])
3003            .build()
3004            .unwrap();
3005
3006        let columns = [Arc::new(DictionaryArray::<Int32Type>::from(data)) as ArrayRef];
3007        let field = SortField::new(data_type.clone());
3008        let converter = RowConverter::new(vec![field]).unwrap();
3009        let rows = converter.convert_columns(&columns).unwrap();
3010
3011        assert_eq!(rows.row(0), rows.row(1));
3012        assert_eq!(rows.row(3), rows.row(4));
3013        assert_eq!(rows.row(4), rows.row(5));
3014        assert!(rows.row(3) < rows.row(0));
3015    }
3016
3017    #[test]
3018    fn test_from_binary_shared_buffer() {
3019        let converter = RowConverter::new(vec![SortField::new(DataType::Binary)]).unwrap();
3020        let array = Arc::new(BinaryArray::from_iter_values([&[0xFF]])) as _;
3021        let rows = converter.convert_columns(&[array]).unwrap();
3022        let binary_rows = rows.try_into_binary().expect("known-small rows");
3023        let _binary_rows_shared_buffer = binary_rows.clone();
3024
3025        let parsed = converter.from_binary(binary_rows);
3026
3027        converter.convert_rows(parsed.iter()).unwrap();
3028    }
3029
3030    #[test]
3031    #[should_panic(expected = "Encountered non UTF-8 data")]
3032    fn test_invalid_utf8() {
3033        let converter = RowConverter::new(vec![SortField::new(DataType::Binary)]).unwrap();
3034        let array = Arc::new(BinaryArray::from_iter_values([&[0xFF]])) as _;
3035        let rows = converter.convert_columns(&[array]).unwrap();
3036        let binary_row = rows.row(0);
3037
3038        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
3039        let parser = converter.parser();
3040        let utf8_row = parser.parse(binary_row.as_ref());
3041
3042        converter.convert_rows(std::iter::once(utf8_row)).unwrap();
3043    }
3044
3045    #[test]
3046    #[should_panic(expected = "Encountered non UTF-8 data")]
3047    fn test_invalid_utf8_array() {
3048        let converter = RowConverter::new(vec![SortField::new(DataType::Binary)]).unwrap();
3049        let array = Arc::new(BinaryArray::from_iter_values([&[0xFF]])) as _;
3050        let rows = converter.convert_columns(&[array]).unwrap();
3051        let binary_rows = rows.try_into_binary().expect("known-small rows");
3052
3053        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
3054        let parsed = converter.from_binary(binary_rows);
3055
3056        converter.convert_rows(parsed.iter()).unwrap();
3057    }
3058
3059    #[test]
3060    #[should_panic(expected = "index out of bounds")]
3061    fn test_invalid_empty() {
3062        let binary_row: &[u8] = &[];
3063
3064        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
3065        let parser = converter.parser();
3066        let utf8_row = parser.parse(binary_row.as_ref());
3067
3068        converter.convert_rows(std::iter::once(utf8_row)).unwrap();
3069    }
3070
3071    #[test]
3072    #[should_panic(expected = "index out of bounds")]
3073    fn test_invalid_empty_array() {
3074        let row: &[u8] = &[];
3075        let binary_rows = BinaryArray::from(vec![row]);
3076
3077        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
3078        let parsed = converter.from_binary(binary_rows);
3079
3080        converter.convert_rows(parsed.iter()).unwrap();
3081    }
3082
3083    #[test]
3084    #[should_panic(expected = "index out of bounds")]
3085    fn test_invalid_truncated() {
3086        let binary_row: &[u8] = &[0x02];
3087
3088        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
3089        let parser = converter.parser();
3090        let utf8_row = parser.parse(binary_row.as_ref());
3091
3092        converter.convert_rows(std::iter::once(utf8_row)).unwrap();
3093    }
3094
3095    #[test]
3096    #[should_panic(expected = "index out of bounds")]
3097    fn test_invalid_truncated_array() {
3098        let row: &[u8] = &[0x02];
3099        let binary_rows = BinaryArray::from(vec![row]);
3100
3101        let converter = RowConverter::new(vec![SortField::new(DataType::Utf8)]).unwrap();
3102        let parsed = converter.from_binary(binary_rows);
3103
3104        converter.convert_rows(parsed.iter()).unwrap();
3105    }
3106
3107    #[test]
3108    #[should_panic(expected = "rows were not produced by this RowConverter")]
3109    fn test_different_converter() {
3110        let values = Arc::new(Int32Array::from_iter([Some(1), Some(-1)]));
3111        let converter = RowConverter::new(vec![SortField::new(DataType::Int32)]).unwrap();
3112        let rows = converter.convert_columns(&[values]).unwrap();
3113
3114        let converter = RowConverter::new(vec![SortField::new(DataType::Int32)]).unwrap();
3115        let _ = converter.convert_rows(&rows);
3116    }
3117
3118    fn test_single_list<O: OffsetSizeTrait>() {
3119        let mut builder = GenericListBuilder::<O, _>::new(Int32Builder::new());
3120        builder.values().append_value(32);
3121        builder.values().append_value(52);
3122        builder.values().append_value(32);
3123        builder.append(true);
3124        builder.values().append_value(32);
3125        builder.values().append_value(52);
3126        builder.values().append_value(12);
3127        builder.append(true);
3128        builder.values().append_value(32);
3129        builder.values().append_value(52);
3130        builder.append(true);
3131        builder.values().append_value(32); // MASKED
3132        builder.values().append_value(52); // MASKED
3133        builder.append(false);
3134        builder.values().append_value(32);
3135        builder.values().append_null();
3136        builder.append(true);
3137        builder.append(true);
3138        builder.values().append_value(17); // MASKED
3139        builder.values().append_null(); // MASKED
3140        builder.append(false);
3141
3142        let list = Arc::new(builder.finish()) as ArrayRef;
3143        let d = list.data_type().clone();
3144
3145        let converter = RowConverter::new(vec![SortField::new(d.clone())]).unwrap();
3146
3147        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3148        assert!(rows.row(0) > rows.row(1)); // [32, 52, 32] > [32, 52, 12]
3149        assert!(rows.row(2) < rows.row(1)); // [32, 52] < [32, 52, 12]
3150        assert!(rows.row(3) < rows.row(2)); // null < [32, 52]
3151        assert!(rows.row(4) < rows.row(2)); // [32, null] < [32, 52]
3152        assert!(rows.row(5) < rows.row(2)); // [] < [32, 52]
3153        assert!(rows.row(3) < rows.row(5)); // null < []
3154        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3155
3156        let back = converter.convert_rows(&rows).unwrap();
3157        assert_eq!(back.len(), 1);
3158        back[0].to_data().validate_full().unwrap();
3159        assert_eq!(&back[0], &list);
3160
3161        let options = SortOptions::default().asc().with_nulls_first(false);
3162        let field = SortField::new_with_options(d.clone(), options);
3163        let converter = RowConverter::new(vec![field]).unwrap();
3164        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3165
3166        assert!(rows.row(0) > rows.row(1)); // [32, 52, 32] > [32, 52, 12]
3167        assert!(rows.row(2) < rows.row(1)); // [32, 52] < [32, 52, 12]
3168        assert!(rows.row(3) > rows.row(2)); // null > [32, 52]
3169        assert!(rows.row(4) > rows.row(2)); // [32, null] > [32, 52]
3170        assert!(rows.row(5) < rows.row(2)); // [] < [32, 52]
3171        assert!(rows.row(3) > rows.row(5)); // null > []
3172        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3173
3174        let back = converter.convert_rows(&rows).unwrap();
3175        assert_eq!(back.len(), 1);
3176        back[0].to_data().validate_full().unwrap();
3177        assert_eq!(&back[0], &list);
3178
3179        let options = SortOptions::default().desc().with_nulls_first(false);
3180        let field = SortField::new_with_options(d.clone(), options);
3181        let converter = RowConverter::new(vec![field]).unwrap();
3182        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3183
3184        assert!(rows.row(0) < rows.row(1)); // [32, 52, 32] < [32, 52, 12]
3185        assert!(rows.row(2) > rows.row(1)); // [32, 52] > [32, 52, 12]
3186        assert!(rows.row(3) > rows.row(2)); // null > [32, 52]
3187        assert!(rows.row(4) > rows.row(2)); // [32, null] > [32, 52]
3188        assert!(rows.row(5) > rows.row(2)); // [] > [32, 52]
3189        assert!(rows.row(3) > rows.row(5)); // null > []
3190        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3191
3192        let back = converter.convert_rows(&rows).unwrap();
3193        assert_eq!(back.len(), 1);
3194        back[0].to_data().validate_full().unwrap();
3195        assert_eq!(&back[0], &list);
3196
3197        let options = SortOptions::default().desc().with_nulls_first(true);
3198        let field = SortField::new_with_options(d, options);
3199        let converter = RowConverter::new(vec![field]).unwrap();
3200        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3201
3202        assert!(rows.row(0) < rows.row(1)); // [32, 52, 32] < [32, 52, 12]
3203        assert!(rows.row(2) > rows.row(1)); // [32, 52] > [32, 52, 12]
3204        assert!(rows.row(3) < rows.row(2)); // null < [32, 52]
3205        assert!(rows.row(4) < rows.row(2)); // [32, null] < [32, 52]
3206        assert!(rows.row(5) > rows.row(2)); // [] > [32, 52]
3207        assert!(rows.row(3) < rows.row(5)); // null < []
3208        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3209
3210        let back = converter.convert_rows(&rows).unwrap();
3211        assert_eq!(back.len(), 1);
3212        back[0].to_data().validate_full().unwrap();
3213        assert_eq!(&back[0], &list);
3214
3215        let sliced_list = list.slice(1, 5);
3216        let rows_on_sliced_list = converter
3217            .convert_columns(&[Arc::clone(&sliced_list)])
3218            .unwrap();
3219
3220        assert!(rows_on_sliced_list.row(1) > rows_on_sliced_list.row(0)); // [32, 52] > [32, 52, 12]
3221        assert!(rows_on_sliced_list.row(2) < rows_on_sliced_list.row(1)); // null < [32, 52]
3222        assert!(rows_on_sliced_list.row(3) < rows_on_sliced_list.row(1)); // [32, null] < [32, 52]
3223        assert!(rows_on_sliced_list.row(4) > rows_on_sliced_list.row(1)); // [] > [32, 52]
3224        assert!(rows_on_sliced_list.row(2) < rows_on_sliced_list.row(4)); // null < []
3225
3226        let back = converter.convert_rows(&rows_on_sliced_list).unwrap();
3227        assert_eq!(back.len(), 1);
3228        back[0].to_data().validate_full().unwrap();
3229        assert_eq!(&back[0], &sliced_list);
3230    }
3231
3232    fn test_nested_list<O: OffsetSizeTrait>() {
3233        let mut builder =
3234            GenericListBuilder::<O, _>::new(GenericListBuilder::<O, _>::new(Int32Builder::new()));
3235
3236        builder.values().values().append_value(1);
3237        builder.values().values().append_value(2);
3238        builder.values().append(true);
3239        builder.values().values().append_value(1);
3240        builder.values().values().append_null();
3241        builder.values().append(true);
3242        builder.append(true);
3243
3244        builder.values().values().append_value(1);
3245        builder.values().values().append_null();
3246        builder.values().append(true);
3247        builder.values().values().append_value(1);
3248        builder.values().values().append_null();
3249        builder.values().append(true);
3250        builder.append(true);
3251
3252        builder.values().values().append_value(1);
3253        builder.values().values().append_null();
3254        builder.values().append(true);
3255        builder.values().append(false);
3256        builder.append(true);
3257        builder.append(false);
3258
3259        builder.values().values().append_value(1);
3260        builder.values().values().append_value(2);
3261        builder.values().append(true);
3262        builder.append(true);
3263
3264        let list = Arc::new(builder.finish()) as ArrayRef;
3265        let d = list.data_type().clone();
3266
3267        // [
3268        //   [[1, 2], [1, null]],
3269        //   [[1, null], [1, null]],
3270        //   [[1, null], null]
3271        //   null
3272        //   [[1, 2]]
3273        // ]
3274        let options = SortOptions::default().asc().with_nulls_first(true);
3275        let field = SortField::new_with_options(d.clone(), options);
3276        let converter = RowConverter::new(vec![field]).unwrap();
3277        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3278
3279        assert!(rows.row(0) > rows.row(1));
3280        assert!(rows.row(1) > rows.row(2));
3281        assert!(rows.row(2) > rows.row(3));
3282        assert!(rows.row(4) < rows.row(0));
3283        assert!(rows.row(4) > rows.row(1));
3284
3285        let back = converter.convert_rows(&rows).unwrap();
3286        assert_eq!(back.len(), 1);
3287        back[0].to_data().validate_full().unwrap();
3288        assert_eq!(&back[0], &list);
3289
3290        let options = SortOptions::default().desc().with_nulls_first(true);
3291        let field = SortField::new_with_options(d.clone(), options);
3292        let converter = RowConverter::new(vec![field]).unwrap();
3293        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3294
3295        assert!(rows.row(0) > rows.row(1));
3296        assert!(rows.row(1) > rows.row(2));
3297        assert!(rows.row(2) > rows.row(3));
3298        assert!(rows.row(4) > rows.row(0));
3299        assert!(rows.row(4) > rows.row(1));
3300
3301        let back = converter.convert_rows(&rows).unwrap();
3302        assert_eq!(back.len(), 1);
3303        back[0].to_data().validate_full().unwrap();
3304        assert_eq!(&back[0], &list);
3305
3306        let options = SortOptions::default().desc().with_nulls_first(false);
3307        let field = SortField::new_with_options(d, options);
3308        let converter = RowConverter::new(vec![field]).unwrap();
3309        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3310
3311        assert!(rows.row(0) < rows.row(1));
3312        assert!(rows.row(1) < rows.row(2));
3313        assert!(rows.row(2) < rows.row(3));
3314        assert!(rows.row(4) > rows.row(0));
3315        assert!(rows.row(4) < rows.row(1));
3316
3317        let back = converter.convert_rows(&rows).unwrap();
3318        assert_eq!(back.len(), 1);
3319        back[0].to_data().validate_full().unwrap();
3320        assert_eq!(&back[0], &list);
3321
3322        let sliced_list = list.slice(1, 3);
3323        let rows = converter
3324            .convert_columns(&[Arc::clone(&sliced_list)])
3325            .unwrap();
3326
3327        assert!(rows.row(0) < rows.row(1));
3328        assert!(rows.row(1) < rows.row(2));
3329
3330        let back = converter.convert_rows(&rows).unwrap();
3331        assert_eq!(back.len(), 1);
3332        back[0].to_data().validate_full().unwrap();
3333        assert_eq!(&back[0], &sliced_list);
3334    }
3335
3336    #[test]
3337    fn test_list() {
3338        test_single_list::<i32>();
3339        test_nested_list::<i32>();
3340    }
3341
3342    #[test]
3343    fn test_large_list() {
3344        test_single_list::<i64>();
3345        test_nested_list::<i64>();
3346    }
3347
3348    fn test_single_list_view<O: OffsetSizeTrait>() {
3349        let mut builder = GenericListViewBuilder::<O, _>::new(Int32Builder::new());
3350        builder.values().append_value(32);
3351        builder.values().append_value(52);
3352        builder.values().append_value(32);
3353        builder.append(true);
3354        builder.values().append_value(32);
3355        builder.values().append_value(52);
3356        builder.values().append_value(12);
3357        builder.append(true);
3358        builder.values().append_value(32);
3359        builder.values().append_value(52);
3360        builder.append(true);
3361        builder.values().append_value(32); // MASKED
3362        builder.values().append_value(52); // MASKED
3363        builder.append(false);
3364        builder.values().append_value(32);
3365        builder.values().append_null();
3366        builder.append(true);
3367        builder.append(true);
3368        builder.values().append_value(17); // MASKED
3369        builder.values().append_null(); // MASKED
3370        builder.append(false);
3371
3372        let list = Arc::new(builder.finish()) as ArrayRef;
3373        let d = list.data_type().clone();
3374
3375        let converter = RowConverter::new(vec![SortField::new(d.clone())]).unwrap();
3376
3377        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3378        assert!(rows.row(0) > rows.row(1)); // [32, 52, 32] > [32, 52, 12]
3379        assert!(rows.row(2) < rows.row(1)); // [32, 52] < [32, 52, 12]
3380        assert!(rows.row(3) < rows.row(2)); // null < [32, 52]
3381        assert!(rows.row(4) < rows.row(2)); // [32, null] < [32, 52]
3382        assert!(rows.row(5) < rows.row(2)); // [] < [32, 52]
3383        assert!(rows.row(3) < rows.row(5)); // null < []
3384        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3385
3386        let back = converter.convert_rows(&rows).unwrap();
3387        assert_eq!(back.len(), 1);
3388        back[0].to_data().validate_full().unwrap();
3389
3390        // Verify the content matches (ListView may have different physical layout but same logical content)
3391        let back_list_view = back[0]
3392            .as_any()
3393            .downcast_ref::<GenericListViewArray<O>>()
3394            .unwrap();
3395        let orig_list_view = list
3396            .as_any()
3397            .downcast_ref::<GenericListViewArray<O>>()
3398            .unwrap();
3399
3400        assert_eq!(back_list_view.len(), orig_list_view.len());
3401        for i in 0..back_list_view.len() {
3402            assert_eq!(back_list_view.is_valid(i), orig_list_view.is_valid(i));
3403            if back_list_view.is_valid(i) {
3404                assert_eq!(&back_list_view.value(i), &orig_list_view.value(i));
3405            }
3406        }
3407
3408        let options = SortOptions::default().asc().with_nulls_first(false);
3409        let field = SortField::new_with_options(d.clone(), options);
3410        let converter = RowConverter::new(vec![field]).unwrap();
3411        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3412
3413        assert!(rows.row(0) > rows.row(1)); // [32, 52, 32] > [32, 52, 12]
3414        assert!(rows.row(2) < rows.row(1)); // [32, 52] < [32, 52, 12]
3415        assert!(rows.row(3) > rows.row(2)); // null > [32, 52]
3416        assert!(rows.row(4) > rows.row(2)); // [32, null] > [32, 52]
3417        assert!(rows.row(5) < rows.row(2)); // [] < [32, 52]
3418        assert!(rows.row(3) > rows.row(5)); // null > []
3419        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3420
3421        let back = converter.convert_rows(&rows).unwrap();
3422        assert_eq!(back.len(), 1);
3423        back[0].to_data().validate_full().unwrap();
3424
3425        let options = SortOptions::default().desc().with_nulls_first(false);
3426        let field = SortField::new_with_options(d.clone(), options);
3427        let converter = RowConverter::new(vec![field]).unwrap();
3428        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3429
3430        assert!(rows.row(0) < rows.row(1)); // [32, 52, 32] < [32, 52, 12]
3431        assert!(rows.row(2) > rows.row(1)); // [32, 52] > [32, 52, 12]
3432        assert!(rows.row(3) > rows.row(2)); // null > [32, 52]
3433        assert!(rows.row(4) > rows.row(2)); // [32, null] > [32, 52]
3434        assert!(rows.row(5) > rows.row(2)); // [] > [32, 52]
3435        assert!(rows.row(3) > rows.row(5)); // null > []
3436        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3437
3438        let back = converter.convert_rows(&rows).unwrap();
3439        assert_eq!(back.len(), 1);
3440        back[0].to_data().validate_full().unwrap();
3441
3442        let options = SortOptions::default().desc().with_nulls_first(true);
3443        let field = SortField::new_with_options(d, options);
3444        let converter = RowConverter::new(vec![field]).unwrap();
3445        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3446
3447        assert!(rows.row(0) < rows.row(1)); // [32, 52, 32] < [32, 52, 12]
3448        assert!(rows.row(2) > rows.row(1)); // [32, 52] > [32, 52, 12]
3449        assert!(rows.row(3) < rows.row(2)); // null < [32, 52]
3450        assert!(rows.row(4) < rows.row(2)); // [32, null] < [32, 52]
3451        assert!(rows.row(5) > rows.row(2)); // [] > [32, 52]
3452        assert!(rows.row(3) < rows.row(5)); // null < []
3453        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3454
3455        let back = converter.convert_rows(&rows).unwrap();
3456        assert_eq!(back.len(), 1);
3457        back[0].to_data().validate_full().unwrap();
3458
3459        let sliced_list = list.slice(1, 5);
3460        let rows_on_sliced_list = converter
3461            .convert_columns(&[Arc::clone(&sliced_list)])
3462            .unwrap();
3463
3464        assert!(rows_on_sliced_list.row(1) > rows_on_sliced_list.row(0)); // [32, 52] > [32, 52, 12]
3465        assert!(rows_on_sliced_list.row(2) < rows_on_sliced_list.row(1)); // null < [32, 52]
3466        assert!(rows_on_sliced_list.row(3) < rows_on_sliced_list.row(1)); // [32, null] < [32, 52]
3467        assert!(rows_on_sliced_list.row(4) > rows_on_sliced_list.row(1)); // [] > [32, 52]
3468        assert!(rows_on_sliced_list.row(2) < rows_on_sliced_list.row(4)); // null < []
3469
3470        let back = converter.convert_rows(&rows_on_sliced_list).unwrap();
3471        assert_eq!(back.len(), 1);
3472        back[0].to_data().validate_full().unwrap();
3473    }
3474
3475    fn test_nested_list_view<O: OffsetSizeTrait>() {
3476        let mut builder = GenericListViewBuilder::<O, _>::new(GenericListViewBuilder::<O, _>::new(
3477            Int32Builder::new(),
3478        ));
3479
3480        // Row 0: [[1, 2], [1, null]]
3481        builder.values().values().append_value(1);
3482        builder.values().values().append_value(2);
3483        builder.values().append(true);
3484        builder.values().values().append_value(1);
3485        builder.values().values().append_null();
3486        builder.values().append(true);
3487        builder.append(true);
3488
3489        // Row 1: [[1, null], [1, null]]
3490        builder.values().values().append_value(1);
3491        builder.values().values().append_null();
3492        builder.values().append(true);
3493        builder.values().values().append_value(1);
3494        builder.values().values().append_null();
3495        builder.values().append(true);
3496        builder.append(true);
3497
3498        // Row 2: [[1, null], null]
3499        builder.values().values().append_value(1);
3500        builder.values().values().append_null();
3501        builder.values().append(true);
3502        builder.values().append(false);
3503        builder.append(true);
3504
3505        // Row 3: null
3506        builder.append(false);
3507
3508        // Row 4: [[1, 2]]
3509        builder.values().values().append_value(1);
3510        builder.values().values().append_value(2);
3511        builder.values().append(true);
3512        builder.append(true);
3513
3514        let list = Arc::new(builder.finish()) as ArrayRef;
3515        let d = list.data_type().clone();
3516
3517        // [
3518        //   [[1, 2], [1, null]],
3519        //   [[1, null], [1, null]],
3520        //   [[1, null], null]
3521        //   null
3522        //   [[1, 2]]
3523        // ]
3524        let options = SortOptions::default().asc().with_nulls_first(true);
3525        let field = SortField::new_with_options(d.clone(), options);
3526        let converter = RowConverter::new(vec![field]).unwrap();
3527        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3528
3529        assert!(rows.row(0) > rows.row(1));
3530        assert!(rows.row(1) > rows.row(2));
3531        assert!(rows.row(2) > rows.row(3));
3532        assert!(rows.row(4) < rows.row(0));
3533        assert!(rows.row(4) > rows.row(1));
3534
3535        let back = converter.convert_rows(&rows).unwrap();
3536        assert_eq!(back.len(), 1);
3537        back[0].to_data().validate_full().unwrap();
3538
3539        // Verify the content matches (ListView may have different physical layout but same logical content)
3540        let back_list_view = back[0]
3541            .as_any()
3542            .downcast_ref::<GenericListViewArray<O>>()
3543            .unwrap();
3544        let orig_list_view = list
3545            .as_any()
3546            .downcast_ref::<GenericListViewArray<O>>()
3547            .unwrap();
3548
3549        assert_eq!(back_list_view.len(), orig_list_view.len());
3550        for i in 0..back_list_view.len() {
3551            assert_eq!(back_list_view.is_valid(i), orig_list_view.is_valid(i));
3552            if back_list_view.is_valid(i) {
3553                assert_eq!(&back_list_view.value(i), &orig_list_view.value(i));
3554            }
3555        }
3556
3557        let options = SortOptions::default().desc().with_nulls_first(true);
3558        let field = SortField::new_with_options(d.clone(), options);
3559        let converter = RowConverter::new(vec![field]).unwrap();
3560        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3561
3562        assert!(rows.row(0) > rows.row(1));
3563        assert!(rows.row(1) > rows.row(2));
3564        assert!(rows.row(2) > rows.row(3));
3565        assert!(rows.row(4) > rows.row(0));
3566        assert!(rows.row(4) > rows.row(1));
3567
3568        let back = converter.convert_rows(&rows).unwrap();
3569        assert_eq!(back.len(), 1);
3570        back[0].to_data().validate_full().unwrap();
3571
3572        // Verify the content matches
3573        let back_list_view = back[0]
3574            .as_any()
3575            .downcast_ref::<GenericListViewArray<O>>()
3576            .unwrap();
3577
3578        assert_eq!(back_list_view.len(), orig_list_view.len());
3579        for i in 0..back_list_view.len() {
3580            assert_eq!(back_list_view.is_valid(i), orig_list_view.is_valid(i));
3581            if back_list_view.is_valid(i) {
3582                assert_eq!(&back_list_view.value(i), &orig_list_view.value(i));
3583            }
3584        }
3585
3586        let options = SortOptions::default().desc().with_nulls_first(false);
3587        let field = SortField::new_with_options(d.clone(), options);
3588        let converter = RowConverter::new(vec![field]).unwrap();
3589        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3590
3591        assert!(rows.row(0) < rows.row(1));
3592        assert!(rows.row(1) < rows.row(2));
3593        assert!(rows.row(2) < rows.row(3));
3594        assert!(rows.row(4) > rows.row(0));
3595        assert!(rows.row(4) < rows.row(1));
3596
3597        let back = converter.convert_rows(&rows).unwrap();
3598        assert_eq!(back.len(), 1);
3599        back[0].to_data().validate_full().unwrap();
3600
3601        // Verify the content matches
3602        let back_list_view = back[0]
3603            .as_any()
3604            .downcast_ref::<GenericListViewArray<O>>()
3605            .unwrap();
3606
3607        assert_eq!(back_list_view.len(), orig_list_view.len());
3608        for i in 0..back_list_view.len() {
3609            assert_eq!(back_list_view.is_valid(i), orig_list_view.is_valid(i));
3610            if back_list_view.is_valid(i) {
3611                assert_eq!(&back_list_view.value(i), &orig_list_view.value(i));
3612            }
3613        }
3614
3615        let sliced_list = list.slice(1, 3);
3616        let rows = converter
3617            .convert_columns(&[Arc::clone(&sliced_list)])
3618            .unwrap();
3619
3620        assert!(rows.row(0) < rows.row(1));
3621        assert!(rows.row(1) < rows.row(2));
3622
3623        let back = converter.convert_rows(&rows).unwrap();
3624        assert_eq!(back.len(), 1);
3625        back[0].to_data().validate_full().unwrap();
3626    }
3627
3628    #[test]
3629    fn test_list_view() {
3630        test_single_list_view::<i32>();
3631        test_nested_list_view::<i32>();
3632    }
3633
3634    #[test]
3635    fn test_large_list_view() {
3636        test_single_list_view::<i64>();
3637        test_nested_list_view::<i64>();
3638    }
3639
3640    fn test_list_view_with_shared_values<O: OffsetSizeTrait>() {
3641        // Create a values array: [1, 2, 3, 4, 5, 6, 7, 8]
3642        let values = Int32Array::from(vec![1, 2, 3, 4, 5, 6, 7, 8]);
3643        let field = Arc::new(Field::new_list_field(DataType::Int32, true));
3644
3645        // Create a ListView where:
3646        // - Row 0: offset=0, size=3 -> [1, 2, 3]
3647        // - Row 1: offset=0, size=3 -> [1, 2, 3] (same offset+size as row 0)
3648        // - Row 2: offset=5, size=2 -> [6, 7] (non-monotonic offset)
3649        // - Row 3: offset=2, size=2 -> [3, 4] (offset goes back)
3650        // - Row 4: offset=1, size=4 -> [2, 3, 4, 5] (subset of values that contains row 3's range)
3651        // - Row 5: offset=2, size=1 -> [3] (subset of row 3 and row 4)
3652        let offsets = ScalarBuffer::<O>::from(vec![
3653            O::from_usize(0).unwrap(),
3654            O::from_usize(0).unwrap(),
3655            O::from_usize(5).unwrap(),
3656            O::from_usize(2).unwrap(),
3657            O::from_usize(1).unwrap(),
3658            O::from_usize(2).unwrap(),
3659        ]);
3660        let sizes = ScalarBuffer::<O>::from(vec![
3661            O::from_usize(3).unwrap(),
3662            O::from_usize(3).unwrap(),
3663            O::from_usize(2).unwrap(),
3664            O::from_usize(2).unwrap(),
3665            O::from_usize(4).unwrap(),
3666            O::from_usize(1).unwrap(),
3667        ]);
3668
3669        let list_view: GenericListViewArray<O> =
3670            GenericListViewArray::try_new(field, offsets, sizes, Arc::new(values), None).unwrap();
3671
3672        let d = list_view.data_type().clone();
3673        let list = Arc::new(list_view) as ArrayRef;
3674
3675        let converter = RowConverter::new(vec![SortField::new(d.clone())]).unwrap();
3676        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3677
3678        // Row 0 and Row 1 have the same content [1, 2, 3], so they should be equal
3679        assert_eq!(rows.row(0), rows.row(1));
3680
3681        // [1, 2, 3] < [6, 7] (comparing first elements: 1 < 6)
3682        assert!(rows.row(0) < rows.row(2));
3683
3684        // [3, 4] > [1, 2, 3] (comparing first elements: 3 > 1)
3685        assert!(rows.row(3) > rows.row(0));
3686
3687        // [2, 3, 4, 5] > [1, 2, 3] (comparing first elements: 2 > 1)
3688        assert!(rows.row(4) > rows.row(0));
3689
3690        // [3] < [3, 4] (same prefix but shorter)
3691        assert!(rows.row(5) < rows.row(3));
3692
3693        // [3] < [2, 3, 4, 5] (comparing first elements: 3 > 2)
3694        assert!(rows.row(5) > rows.row(4));
3695
3696        // Round-trip conversion
3697        let back = converter.convert_rows(&rows).unwrap();
3698        assert_eq!(back.len(), 1);
3699        back[0].to_data().validate_full().unwrap();
3700
3701        // Verify logical content matches
3702        let back_list_view = back[0]
3703            .as_any()
3704            .downcast_ref::<GenericListViewArray<O>>()
3705            .unwrap();
3706        let orig_list_view = list
3707            .as_any()
3708            .downcast_ref::<GenericListViewArray<O>>()
3709            .unwrap();
3710
3711        assert_eq!(back_list_view.len(), orig_list_view.len());
3712        for i in 0..back_list_view.len() {
3713            assert_eq!(back_list_view.is_valid(i), orig_list_view.is_valid(i));
3714            if back_list_view.is_valid(i) {
3715                assert_eq!(&back_list_view.value(i), &orig_list_view.value(i));
3716            }
3717        }
3718
3719        // Test with descending order
3720        let options = SortOptions::default().desc();
3721        let field = SortField::new_with_options(d, options);
3722        let converter = RowConverter::new(vec![field]).unwrap();
3723        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3724
3725        // In descending order, comparisons are reversed
3726        assert_eq!(rows.row(0), rows.row(1)); // Equal rows stay equal
3727        assert!(rows.row(0) > rows.row(2)); // [1, 2, 3] > [6, 7] in desc
3728        assert!(rows.row(3) < rows.row(0)); // [3, 4] < [1, 2, 3] in desc
3729
3730        let back = converter.convert_rows(&rows).unwrap();
3731        assert_eq!(back.len(), 1);
3732        back[0].to_data().validate_full().unwrap();
3733    }
3734
3735    #[test]
3736    fn test_list_view_shared_values() {
3737        test_list_view_with_shared_values::<i32>();
3738    }
3739
3740    #[test]
3741    fn test_large_list_view_shared_values() {
3742        test_list_view_with_shared_values::<i64>();
3743    }
3744
3745    #[test]
3746    fn test_fixed_size_list() {
3747        let mut builder = FixedSizeListBuilder::new(Int32Builder::new(), 3);
3748        builder.values().append_value(32);
3749        builder.values().append_value(52);
3750        builder.values().append_value(32);
3751        builder.append(true);
3752        builder.values().append_value(32);
3753        builder.values().append_value(52);
3754        builder.values().append_value(12);
3755        builder.append(true);
3756        builder.values().append_value(32);
3757        builder.values().append_value(52);
3758        builder.values().append_null();
3759        builder.append(true);
3760        builder.values().append_value(32); // MASKED
3761        builder.values().append_value(52); // MASKED
3762        builder.values().append_value(13); // MASKED
3763        builder.append(false);
3764        builder.values().append_value(32);
3765        builder.values().append_null();
3766        builder.values().append_null();
3767        builder.append(true);
3768        builder.values().append_null();
3769        builder.values().append_null();
3770        builder.values().append_null();
3771        builder.append(true);
3772        builder.values().append_value(17); // MASKED
3773        builder.values().append_null(); // MASKED
3774        builder.values().append_value(77); // MASKED
3775        builder.append(false);
3776
3777        let list = Arc::new(builder.finish()) as ArrayRef;
3778        let d = list.data_type().clone();
3779
3780        // Default sorting (ascending, nulls first)
3781        let converter = RowConverter::new(vec![SortField::new(d.clone())]).unwrap();
3782
3783        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3784        assert!(rows.row(0) > rows.row(1)); // [32, 52, 32] > [32, 52, 12]
3785        assert!(rows.row(2) < rows.row(1)); // [32, 52, null] < [32, 52, 12]
3786        assert!(rows.row(3) < rows.row(2)); // null < [32, 52, null]
3787        assert!(rows.row(4) < rows.row(2)); // [32, null, null] < [32, 52, null]
3788        assert!(rows.row(5) < rows.row(2)); // [null, null, null] < [32, 52, null]
3789        assert!(rows.row(3) < rows.row(5)); // null < [null, null, null]
3790        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3791
3792        let back = converter.convert_rows(&rows).unwrap();
3793        assert_eq!(back.len(), 1);
3794        back[0].to_data().validate_full().unwrap();
3795        assert_eq!(&back[0], &list);
3796
3797        // Ascending, null last
3798        let options = SortOptions::default().asc().with_nulls_first(false);
3799        let field = SortField::new_with_options(d.clone(), options);
3800        let converter = RowConverter::new(vec![field]).unwrap();
3801        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3802        assert!(rows.row(0) > rows.row(1)); // [32, 52, 32] > [32, 52, 12]
3803        assert!(rows.row(2) > rows.row(1)); // [32, 52, null] > [32, 52, 12]
3804        assert!(rows.row(3) > rows.row(2)); // null > [32, 52, null]
3805        assert!(rows.row(4) > rows.row(2)); // [32, null, null] > [32, 52, null]
3806        assert!(rows.row(5) > rows.row(2)); // [null, null, null] > [32, 52, null]
3807        assert!(rows.row(3) > rows.row(5)); // null > [null, null, null]
3808        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3809
3810        let back = converter.convert_rows(&rows).unwrap();
3811        assert_eq!(back.len(), 1);
3812        back[0].to_data().validate_full().unwrap();
3813        assert_eq!(&back[0], &list);
3814
3815        // Descending, nulls last
3816        let options = SortOptions::default().desc().with_nulls_first(false);
3817        let field = SortField::new_with_options(d.clone(), options);
3818        let converter = RowConverter::new(vec![field]).unwrap();
3819        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3820        assert!(rows.row(0) < rows.row(1)); // [32, 52, 32] < [32, 52, 12]
3821        assert!(rows.row(2) > rows.row(1)); // [32, 52, null] > [32, 52, 12]
3822        assert!(rows.row(3) > rows.row(2)); // null > [32, 52, null]
3823        assert!(rows.row(4) > rows.row(2)); // [32, null, null] > [32, 52, null]
3824        assert!(rows.row(5) > rows.row(2)); // [null, null, null] > [32, 52, null]
3825        assert!(rows.row(3) > rows.row(5)); // null > [null, null, null]
3826        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3827
3828        let back = converter.convert_rows(&rows).unwrap();
3829        assert_eq!(back.len(), 1);
3830        back[0].to_data().validate_full().unwrap();
3831        assert_eq!(&back[0], &list);
3832
3833        // Descending, nulls first
3834        let options = SortOptions::default().desc().with_nulls_first(true);
3835        let field = SortField::new_with_options(d, options);
3836        let converter = RowConverter::new(vec![field]).unwrap();
3837        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
3838
3839        assert!(rows.row(0) < rows.row(1)); // [32, 52, 32] < [32, 52, 12]
3840        assert!(rows.row(2) < rows.row(1)); // [32, 52, null] > [32, 52, 12]
3841        assert!(rows.row(3) < rows.row(2)); // null < [32, 52, null]
3842        assert!(rows.row(4) < rows.row(2)); // [32, null, null] < [32, 52, null]
3843        assert!(rows.row(5) < rows.row(2)); // [null, null, null] > [32, 52, null]
3844        assert!(rows.row(3) < rows.row(5)); // null < [null, null, null]
3845        assert_eq!(rows.row(3), rows.row(6)); // null = null (different masked values)
3846
3847        let back = converter.convert_rows(&rows).unwrap();
3848        assert_eq!(back.len(), 1);
3849        back[0].to_data().validate_full().unwrap();
3850        assert_eq!(&back[0], &list);
3851
3852        let sliced_list = list.slice(1, 5);
3853        let rows_on_sliced_list = converter
3854            .convert_columns(&[Arc::clone(&sliced_list)])
3855            .unwrap();
3856
3857        assert!(rows_on_sliced_list.row(2) < rows_on_sliced_list.row(1)); // null < [32, 52, null]
3858        assert!(rows_on_sliced_list.row(3) < rows_on_sliced_list.row(1)); // [32, null, null] < [32, 52, null]
3859        assert!(rows_on_sliced_list.row(4) < rows_on_sliced_list.row(1)); // [null, null, null] > [32, 52, null]
3860        assert!(rows_on_sliced_list.row(2) < rows_on_sliced_list.row(4)); // null < [null, null, null]
3861
3862        let back = converter.convert_rows(&rows_on_sliced_list).unwrap();
3863        assert_eq!(back.len(), 1);
3864        back[0].to_data().validate_full().unwrap();
3865        assert_eq!(&back[0], &sliced_list);
3866    }
3867
3868    #[test]
3869    fn test_two_fixed_size_lists() {
3870        let mut first = FixedSizeListBuilder::new(UInt8Builder::new(), 1);
3871        // 0: [100]
3872        first.values().append_value(100);
3873        first.append(true);
3874        // 1: [101]
3875        first.values().append_value(101);
3876        first.append(true);
3877        // 2: [102]
3878        first.values().append_value(102);
3879        first.append(true);
3880        // 3: [null]
3881        first.values().append_null();
3882        first.append(true);
3883        // 4: null
3884        first.values().append_null(); // MASKED
3885        first.append(false);
3886        let first = Arc::new(first.finish()) as ArrayRef;
3887        let first_type = first.data_type().clone();
3888
3889        let mut second = FixedSizeListBuilder::new(UInt8Builder::new(), 1);
3890        // 0: [200]
3891        second.values().append_value(200);
3892        second.append(true);
3893        // 1: [201]
3894        second.values().append_value(201);
3895        second.append(true);
3896        // 2: [202]
3897        second.values().append_value(202);
3898        second.append(true);
3899        // 3: [null]
3900        second.values().append_null();
3901        second.append(true);
3902        // 4: null
3903        second.values().append_null(); // MASKED
3904        second.append(false);
3905        let second = Arc::new(second.finish()) as ArrayRef;
3906        let second_type = second.data_type().clone();
3907
3908        let converter = RowConverter::new(vec![
3909            SortField::new(first_type.clone()),
3910            SortField::new(second_type.clone()),
3911        ])
3912        .unwrap();
3913
3914        let rows = converter
3915            .convert_columns(&[Arc::clone(&first), Arc::clone(&second)])
3916            .unwrap();
3917
3918        let back = converter.convert_rows(&rows).unwrap();
3919        assert_eq!(back.len(), 2);
3920        back[0].to_data().validate_full().unwrap();
3921        assert_eq!(&back[0], &first);
3922        back[1].to_data().validate_full().unwrap();
3923        assert_eq!(&back[1], &second);
3924    }
3925
3926    #[test]
3927    fn test_fixed_size_list_with_variable_width_content() {
3928        let mut first = FixedSizeListBuilder::new(
3929            StructBuilder::from_fields(
3930                vec![
3931                    Field::new(
3932                        "timestamp",
3933                        DataType::Timestamp(TimeUnit::Microsecond, Some(Arc::from("UTC"))),
3934                        false,
3935                    ),
3936                    Field::new("offset_minutes", DataType::Int16, false),
3937                    Field::new("time_zone", DataType::Utf8, false),
3938                ],
3939                1,
3940            ),
3941            1,
3942        );
3943        // 0: null
3944        first
3945            .values()
3946            .field_builder::<TimestampMicrosecondBuilder>(0)
3947            .unwrap()
3948            .append_null();
3949        first
3950            .values()
3951            .field_builder::<Int16Builder>(1)
3952            .unwrap()
3953            .append_null();
3954        first
3955            .values()
3956            .field_builder::<StringBuilder>(2)
3957            .unwrap()
3958            .append_null();
3959        first.values().append(false);
3960        first.append(false);
3961        // 1: [null]
3962        first
3963            .values()
3964            .field_builder::<TimestampMicrosecondBuilder>(0)
3965            .unwrap()
3966            .append_null();
3967        first
3968            .values()
3969            .field_builder::<Int16Builder>(1)
3970            .unwrap()
3971            .append_null();
3972        first
3973            .values()
3974            .field_builder::<StringBuilder>(2)
3975            .unwrap()
3976            .append_null();
3977        first.values().append(false);
3978        first.append(true);
3979        // 2: [1970-01-01 00:00:00.000000 UTC]
3980        first
3981            .values()
3982            .field_builder::<TimestampMicrosecondBuilder>(0)
3983            .unwrap()
3984            .append_value(0);
3985        first
3986            .values()
3987            .field_builder::<Int16Builder>(1)
3988            .unwrap()
3989            .append_value(0);
3990        first
3991            .values()
3992            .field_builder::<StringBuilder>(2)
3993            .unwrap()
3994            .append_value("UTC");
3995        first.values().append(true);
3996        first.append(true);
3997        // 3: [2005-09-10 13:30:00.123456 Europe/Warsaw]
3998        first
3999            .values()
4000            .field_builder::<TimestampMicrosecondBuilder>(0)
4001            .unwrap()
4002            .append_value(1126351800123456);
4003        first
4004            .values()
4005            .field_builder::<Int16Builder>(1)
4006            .unwrap()
4007            .append_value(120);
4008        first
4009            .values()
4010            .field_builder::<StringBuilder>(2)
4011            .unwrap()
4012            .append_value("Europe/Warsaw");
4013        first.values().append(true);
4014        first.append(true);
4015        let first = Arc::new(first.finish()) as ArrayRef;
4016        let first_type = first.data_type().clone();
4017
4018        let mut second = StringBuilder::new();
4019        second.append_value("somewhere near");
4020        second.append_null();
4021        second.append_value("Greenwich");
4022        second.append_value("Warsaw");
4023        let second = Arc::new(second.finish()) as ArrayRef;
4024        let second_type = second.data_type().clone();
4025
4026        let converter = RowConverter::new(vec![
4027            SortField::new(first_type.clone()),
4028            SortField::new(second_type.clone()),
4029        ])
4030        .unwrap();
4031
4032        let rows = converter
4033            .convert_columns(&[Arc::clone(&first), Arc::clone(&second)])
4034            .unwrap();
4035
4036        let back = converter.convert_rows(&rows).unwrap();
4037        assert_eq!(back.len(), 2);
4038        back[0].to_data().validate_full().unwrap();
4039        assert_eq!(&back[0], &first);
4040        back[1].to_data().validate_full().unwrap();
4041        assert_eq!(&back[1], &second);
4042    }
4043
4044    fn generate_primitive_array<K>(
4045        rng: &mut impl RngCore,
4046        len: usize,
4047        valid_percent: f64,
4048    ) -> PrimitiveArray<K>
4049    where
4050        K: ArrowPrimitiveType,
4051        StandardUniform: Distribution<K::Native>,
4052    {
4053        (0..len)
4054            .map(|_| rng.random_bool(valid_percent).then(|| rng.random()))
4055            .collect()
4056    }
4057
4058    fn generate_boolean_array(
4059        rng: &mut impl RngCore,
4060        len: usize,
4061        valid_percent: f64,
4062    ) -> BooleanArray {
4063        (0..len)
4064            .map(|_| rng.random_bool(valid_percent).then(|| rng.random_bool(0.5)))
4065            .collect()
4066    }
4067
4068    fn generate_strings<O: OffsetSizeTrait>(
4069        rng: &mut impl RngCore,
4070        len: usize,
4071        valid_percent: f64,
4072    ) -> GenericStringArray<O> {
4073        (0..len)
4074            .map(|_| {
4075                rng.random_bool(valid_percent).then(|| {
4076                    let len = rng.random_range(0..100);
4077                    let bytes = (0..len).map(|_| rng.random_range(0..128)).collect();
4078                    String::from_utf8(bytes).unwrap()
4079                })
4080            })
4081            .collect()
4082    }
4083
4084    fn generate_string_view(
4085        rng: &mut impl RngCore,
4086        len: usize,
4087        valid_percent: f64,
4088    ) -> StringViewArray {
4089        (0..len)
4090            .map(|_| {
4091                rng.random_bool(valid_percent).then(|| {
4092                    let len = rng.random_range(0..100);
4093                    let bytes = (0..len).map(|_| rng.random_range(0..128)).collect();
4094                    String::from_utf8(bytes).unwrap()
4095                })
4096            })
4097            .collect()
4098    }
4099
4100    fn generate_byte_view(
4101        rng: &mut impl RngCore,
4102        len: usize,
4103        valid_percent: f64,
4104    ) -> BinaryViewArray {
4105        (0..len)
4106            .map(|_| {
4107                rng.random_bool(valid_percent).then(|| {
4108                    let len = rng.random_range(0..100);
4109                    let bytes: Vec<_> = (0..len).map(|_| rng.random_range(0..128)).collect();
4110                    bytes
4111                })
4112            })
4113            .collect()
4114    }
4115
4116    fn generate_fixed_stringview_column(len: usize) -> StringViewArray {
4117        let edge_cases = vec![
4118            Some("bar".to_string()),
4119            Some("bar\0".to_string()),
4120            Some("LongerThan12Bytes".to_string()),
4121            Some("LongerThan12Bytez".to_string()),
4122            Some("LongerThan12Bytes\0".to_string()),
4123            Some("LongerThan12Byt".to_string()),
4124            Some("backend one".to_string()),
4125            Some("backend two".to_string()),
4126            Some("a".repeat(257)),
4127            Some("a".repeat(300)),
4128        ];
4129
4130        // Fill up to `len` by repeating edge cases and trimming
4131        let mut values = Vec::with_capacity(len);
4132        for i in 0..len {
4133            values.push(
4134                edge_cases
4135                    .get(i % edge_cases.len())
4136                    .cloned()
4137                    .unwrap_or(None),
4138            );
4139        }
4140
4141        StringViewArray::from(values)
4142    }
4143
4144    fn generate_dictionary<K>(
4145        rng: &mut impl RngCore,
4146        values: ArrayRef,
4147        len: usize,
4148        valid_percent: f64,
4149    ) -> DictionaryArray<K>
4150    where
4151        K: ArrowDictionaryKeyType,
4152        K::Native: SampleUniform,
4153    {
4154        let min_key = K::Native::from_usize(0).unwrap();
4155        let max_key = K::Native::from_usize(values.len()).unwrap();
4156        let keys: PrimitiveArray<K> = (0..len)
4157            .map(|_| {
4158                rng.random_bool(valid_percent)
4159                    .then(|| rng.random_range(min_key..max_key))
4160            })
4161            .collect();
4162
4163        let data_type =
4164            DataType::Dictionary(Box::new(K::DATA_TYPE), Box::new(values.data_type().clone()));
4165
4166        let data = keys
4167            .into_data()
4168            .into_builder()
4169            .data_type(data_type)
4170            .add_child_data(values.to_data())
4171            .build()
4172            .unwrap();
4173
4174        DictionaryArray::from(data)
4175    }
4176
4177    fn generate_fixed_size_binary(
4178        rng: &mut impl RngCore,
4179        len: usize,
4180        valid_percent: f64,
4181    ) -> FixedSizeBinaryArray {
4182        let width = rng.random_range(0..20);
4183        let mut builder = FixedSizeBinaryBuilder::new(width);
4184
4185        let mut b = vec![0; width as usize];
4186        for _ in 0..len {
4187            match rng.random_bool(valid_percent) {
4188                true => {
4189                    b.iter_mut().for_each(|x| *x = rng.random());
4190                    builder.append_value(&b).unwrap();
4191                }
4192                false => builder.append_null(),
4193            }
4194        }
4195
4196        builder.finish()
4197    }
4198
4199    fn generate_struct(rng: &mut impl RngCore, len: usize, valid_percent: f64) -> StructArray {
4200        let nulls = NullBuffer::from_iter((0..len).map(|_| rng.random_bool(valid_percent)));
4201        let a = generate_primitive_array::<Int32Type>(rng, len, valid_percent);
4202        let b = generate_strings::<i32>(rng, len, valid_percent);
4203        let fields = Fields::from(vec![
4204            Field::new("a", DataType::Int32, true),
4205            Field::new("b", DataType::Utf8, true),
4206        ]);
4207        let values = vec![Arc::new(a) as _, Arc::new(b) as _];
4208        StructArray::new(fields, values, Some(nulls))
4209    }
4210
4211    fn generate_list<R: RngCore, F>(
4212        rng: &mut R,
4213        len: usize,
4214        valid_percent: f64,
4215        values: F,
4216    ) -> ListArray
4217    where
4218        F: FnOnce(&mut R, usize) -> ArrayRef,
4219    {
4220        let offsets = OffsetBuffer::<i32>::from_lengths((0..len).map(|_| rng.random_range(0..10)));
4221        let values_len = offsets.last().unwrap().to_usize().unwrap();
4222        let values = values(rng, values_len);
4223        let nulls = NullBuffer::from_iter((0..len).map(|_| rng.random_bool(valid_percent)));
4224        let field = Arc::new(Field::new_list_field(values.data_type().clone(), true));
4225        ListArray::new(field, offsets, values, Some(nulls))
4226    }
4227
4228    fn generate_list_view<F>(
4229        rng: &mut impl RngCore,
4230        len: usize,
4231        valid_percent: f64,
4232        values: F,
4233    ) -> ListViewArray
4234    where
4235        F: FnOnce(usize) -> ArrayRef,
4236    {
4237        // Generate sizes first, then create a values array large enough
4238        let sizes: Vec<i32> = (0..len).map(|_| rng.random_range(0..10)).collect();
4239        let values_len: usize = sizes.iter().map(|s| *s as usize).sum::<usize>().max(1);
4240        let values = values(values_len);
4241
4242        // Generate offsets that can overlap, be non-monotonic, or share ranges
4243        let offsets: Vec<i32> = sizes
4244            .iter()
4245            .map(|&size| {
4246                if size == 0 {
4247                    0
4248                } else {
4249                    rng.random_range(0..=(values_len as i32 - size))
4250                }
4251            })
4252            .collect();
4253
4254        let nulls = NullBuffer::from_iter((0..len).map(|_| rng.random_bool(valid_percent)));
4255        let field = Arc::new(Field::new_list_field(values.data_type().clone(), true));
4256        ListViewArray::new(
4257            field,
4258            ScalarBuffer::from(offsets),
4259            ScalarBuffer::from(sizes),
4260            values,
4261            Some(nulls),
4262        )
4263    }
4264
4265    fn generate_nulls(rng: &mut impl RngCore, len: usize) -> Option<NullBuffer> {
4266        Some(NullBuffer::from_iter(
4267            (0..len).map(|_| rng.random_bool(0.8)),
4268        ))
4269    }
4270
4271    fn change_underlying_null_values_for_primitive<T: ArrowPrimitiveType>(
4272        array: &PrimitiveArray<T>,
4273    ) -> PrimitiveArray<T> {
4274        let (dt, values, nulls) = array.clone().into_parts();
4275
4276        let new_values = ScalarBuffer::<T::Native>::from_iter(
4277            values
4278                .iter()
4279                .zip(nulls.as_ref().unwrap().iter())
4280                .map(|(val, is_valid)| {
4281                    if is_valid {
4282                        *val
4283                    } else {
4284                        val.add_wrapping(T::Native::usize_as(1))
4285                    }
4286                }),
4287        );
4288
4289        PrimitiveArray::new(new_values, nulls).with_data_type(dt)
4290    }
4291
4292    fn change_underline_null_values_for_byte_array<T: ByteArrayType>(
4293        array: &GenericByteArray<T>,
4294    ) -> GenericByteArray<T> {
4295        let (offsets, values, nulls) = array.clone().into_parts();
4296
4297        let new_offsets = OffsetBuffer::<T::Offset>::from_lengths(
4298            offsets
4299                .lengths()
4300                .zip(nulls.as_ref().unwrap().iter())
4301                .map(|(len, is_valid)| if is_valid { len } else { len + 1 }),
4302        );
4303
4304        let mut new_bytes = Vec::<u8>::with_capacity(new_offsets[new_offsets.len() - 1].as_usize());
4305
4306        offsets
4307            .windows(2)
4308            .zip(nulls.as_ref().unwrap().iter())
4309            .for_each(|(start_and_end, is_valid)| {
4310                let start = start_and_end[0].as_usize();
4311                let end = start_and_end[1].as_usize();
4312                new_bytes.extend_from_slice(&values.as_slice()[start..end]);
4313
4314                // add an extra byte
4315                if !is_valid {
4316                    new_bytes.push(b'c');
4317                }
4318            });
4319
4320        GenericByteArray::<T>::new(new_offsets, Buffer::from_vec(new_bytes), nulls)
4321    }
4322
4323    fn change_underline_null_values_for_list_array<O: OffsetSizeTrait>(
4324        array: &GenericListArray<O>,
4325    ) -> GenericListArray<O> {
4326        let (field, offsets, values, nulls) = array.clone().into_parts();
4327
4328        let (new_values, new_offsets) = {
4329            let concat_values = offsets
4330                .windows(2)
4331                .zip(nulls.as_ref().unwrap().iter())
4332                .map(|(start_and_end, is_valid)| {
4333                    let start = start_and_end[0].as_usize();
4334                    let end = start_and_end[1].as_usize();
4335                    if is_valid {
4336                        return (start, end - start);
4337                    }
4338
4339                    // If reached end, we take one less
4340                    if end == values.len() {
4341                        (start, (end - start).saturating_sub(1))
4342                    } else {
4343                        (start, end - start + 1)
4344                    }
4345                })
4346                .map(|(start, length)| values.slice(start, length))
4347                .collect::<Vec<_>>();
4348
4349            let new_offsets =
4350                OffsetBuffer::<O>::from_lengths(concat_values.iter().map(|s| s.len()));
4351
4352            let new_values = {
4353                let values = concat_values.iter().map(|a| a.as_ref()).collect::<Vec<_>>();
4354                arrow_select::concat::concat(&values).expect("should be able to concat")
4355            };
4356
4357            (new_values, new_offsets)
4358        };
4359
4360        GenericListArray::<O>::new(field, new_offsets, new_values, nulls)
4361    }
4362
4363    fn change_underline_null_values(array: &ArrayRef) -> ArrayRef {
4364        if array.null_count() == 0 {
4365            return Arc::clone(array);
4366        }
4367
4368        downcast_primitive_array!(
4369            array => {
4370                let output = change_underlying_null_values_for_primitive(array);
4371
4372                Arc::new(output)
4373            }
4374
4375            DataType::Utf8 => {
4376                Arc::new(change_underline_null_values_for_byte_array(array.as_string::<i32>()))
4377            }
4378            DataType::LargeUtf8 => {
4379                Arc::new(change_underline_null_values_for_byte_array(array.as_string::<i64>()))
4380            }
4381            DataType::Binary => {
4382                Arc::new(change_underline_null_values_for_byte_array(array.as_binary::<i32>()))
4383            }
4384            DataType::LargeBinary => {
4385                Arc::new(change_underline_null_values_for_byte_array(array.as_binary::<i64>()))
4386            }
4387            DataType::List(_) => {
4388                Arc::new(change_underline_null_values_for_list_array(array.as_list::<i32>()))
4389            }
4390            DataType::LargeList(_) => {
4391                Arc::new(change_underline_null_values_for_list_array(array.as_list::<i64>()))
4392            }
4393            _ => {
4394                Arc::clone(array)
4395            }
4396        )
4397    }
4398
4399    fn generate_column(rng: &mut (impl RngCore + Clone), len: usize) -> ArrayRef {
4400        match rng.random_range(0..23) {
4401            0 => Arc::new(generate_primitive_array::<Int32Type>(rng, len, 0.8)),
4402            1 => Arc::new(generate_primitive_array::<UInt32Type>(rng, len, 0.8)),
4403            2 => Arc::new(generate_primitive_array::<Int64Type>(rng, len, 0.8)),
4404            3 => Arc::new(generate_primitive_array::<UInt64Type>(rng, len, 0.8)),
4405            4 => Arc::new(generate_primitive_array::<Float32Type>(rng, len, 0.8)),
4406            5 => Arc::new(generate_primitive_array::<Float64Type>(rng, len, 0.8)),
4407            6 => Arc::new(generate_strings::<i32>(rng, len, 0.8)),
4408            7 => {
4409                let dict_values_len = rng.random_range(1..len);
4410                // Cannot test dictionaries containing null values because of #2687
4411                let strings = Arc::new(generate_strings::<i32>(rng, dict_values_len, 1.0));
4412                Arc::new(generate_dictionary::<Int64Type>(rng, strings, len, 0.8))
4413            }
4414            8 => {
4415                let dict_values_len = rng.random_range(1..len);
4416                // Cannot test dictionaries containing null values because of #2687
4417                let values = Arc::new(generate_primitive_array::<Int64Type>(
4418                    rng,
4419                    dict_values_len,
4420                    1.0,
4421                ));
4422                Arc::new(generate_dictionary::<Int64Type>(rng, values, len, 0.8))
4423            }
4424            9 => Arc::new(generate_fixed_size_binary(rng, len, 0.8)),
4425            10 => Arc::new(generate_struct(rng, len, 0.8)),
4426            11 => Arc::new(generate_list(rng, len, 0.8, |rng, values_len| {
4427                Arc::new(generate_primitive_array::<Int64Type>(rng, values_len, 0.8))
4428            })),
4429            12 => Arc::new(generate_list(rng, len, 0.8, |rng, values_len| {
4430                Arc::new(generate_strings::<i32>(rng, values_len, 0.8))
4431            })),
4432            13 => Arc::new(generate_list(rng, len, 0.8, |rng, values_len| {
4433                Arc::new(generate_struct(rng, values_len, 0.8))
4434            })),
4435            14 => Arc::new(generate_string_view(rng, len, 0.8)),
4436            15 => Arc::new(generate_byte_view(rng, len, 0.8)),
4437            16 => Arc::new(generate_fixed_stringview_column(len)),
4438            17 => Arc::new(
4439                generate_list(&mut rng.clone(), len + 1000, 0.8, |rng, values_len| {
4440                    Arc::new(generate_primitive_array::<Int64Type>(rng, values_len, 0.8))
4441                })
4442                .slice(500, len),
4443            ),
4444            18 => Arc::new(generate_boolean_array(rng, len, 0.8)),
4445            19 => Arc::new(generate_list_view(
4446                &mut rng.clone(),
4447                len,
4448                0.8,
4449                |values_len| Arc::new(generate_primitive_array::<Int64Type>(rng, values_len, 0.8)),
4450            )),
4451            20 => Arc::new(generate_list_view(
4452                &mut rng.clone(),
4453                len,
4454                0.8,
4455                |values_len| Arc::new(generate_strings::<i32>(rng, values_len, 0.8)),
4456            )),
4457            21 => Arc::new(generate_list_view(
4458                &mut rng.clone(),
4459                len,
4460                0.8,
4461                |values_len| Arc::new(generate_struct(rng, values_len, 0.8)),
4462            )),
4463            22 => Arc::new(
4464                generate_list_view(&mut rng.clone(), len + 1000, 0.8, |values_len| {
4465                    Arc::new(generate_primitive_array::<Int64Type>(rng, values_len, 0.8))
4466                })
4467                .slice(500, len),
4468            ),
4469            _ => unreachable!(),
4470        }
4471    }
4472
4473    fn print_row(cols: &[SortColumn], row: usize) -> String {
4474        let t: Vec<_> = cols
4475            .iter()
4476            .map(|x| match x.values.is_valid(row) {
4477                true => {
4478                    let opts = FormatOptions::default().with_null("NULL");
4479                    let formatter = ArrayFormatter::try_new(x.values.as_ref(), &opts).unwrap();
4480                    formatter.value(row).to_string()
4481                }
4482                false => "NULL".to_string(),
4483            })
4484            .collect();
4485        t.join(",")
4486    }
4487
4488    fn print_col_types(cols: &[SortColumn]) -> String {
4489        let t: Vec<_> = cols
4490            .iter()
4491            .map(|x| x.values.data_type().to_string())
4492            .collect();
4493        t.join(",")
4494    }
4495
4496    #[derive(Debug, PartialEq)]
4497    enum Nulls {
4498        /// Keep the generated array as is
4499        AsIs,
4500
4501        /// Replace the null buffer with different null buffer to point to different positions as null
4502        Different,
4503
4504        /// Remove all nulls
4505        None,
4506    }
4507
4508    #[test]
4509    #[cfg_attr(miri, ignore)]
4510    fn fuzz_test() {
4511        let mut rng = StdRng::seed_from_u64(42);
4512        for _ in 0..100 {
4513            for null_behavior in [Nulls::AsIs, Nulls::Different, Nulls::None] {
4514                let num_columns = rng.random_range(1..5);
4515                let len = rng.random_range(5..100);
4516                let mut arrays: Vec<_> = (0..num_columns)
4517                    .map(|_| generate_column(&mut rng, len))
4518                    .collect();
4519
4520                match null_behavior {
4521                    Nulls::AsIs => {
4522                        // Keep as is
4523                    }
4524                    Nulls::Different => {
4525                        // Replace nulls with different nulls to allow for testing different underlying null values
4526                        arrays = arrays
4527                            .into_iter()
4528                            .map(|a| replace_array_nulls(a, generate_nulls(&mut rng, len)))
4529                            .collect()
4530                    }
4531                    Nulls::None => {
4532                        // Remove nulls
4533                        arrays = arrays
4534                            .into_iter()
4535                            .map(|a| replace_array_nulls(a, None))
4536                            .collect()
4537                    }
4538                }
4539
4540                let options: Vec<_> = (0..num_columns)
4541                    .map(|_| SortOptions {
4542                        descending: rng.random_bool(0.5),
4543                        nulls_first: rng.random_bool(0.5),
4544                    })
4545                    .collect();
4546
4547                let sort_columns: Vec<_> = options
4548                    .iter()
4549                    .zip(&arrays)
4550                    .map(|(o, c)| SortColumn {
4551                        values: Arc::clone(c),
4552                        options: Some(*o),
4553                    })
4554                    .collect();
4555
4556                let comparator = LexicographicalComparator::try_new(&sort_columns).unwrap();
4557
4558                let columns: Vec<SortField> = options
4559                    .into_iter()
4560                    .zip(&arrays)
4561                    .map(|(o, a)| SortField::new_with_options(a.data_type().clone(), o))
4562                    .collect();
4563
4564                let converter = RowConverter::new(columns).unwrap();
4565                let rows = converter.convert_columns(&arrays).unwrap();
4566
4567                // Assert that the underlying null values are not taken into account when converting
4568                // even for different inputs
4569                if !matches!(null_behavior, Nulls::None) {
4570                    assert_same_rows_when_changing_input_underlying_null_values(
4571                        &arrays, &converter, &rows,
4572                    );
4573                }
4574
4575                for i in 0..len {
4576                    for j in 0..len {
4577                        let row_i = rows.row(i);
4578                        let row_j = rows.row(j);
4579                        let row_cmp = row_i.cmp(&row_j);
4580                        let lex_cmp = comparator.compare(i, j);
4581                        assert_eq!(
4582                            row_cmp,
4583                            lex_cmp,
4584                            "({:?} vs {:?}) vs ({:?} vs {:?}) for types {}",
4585                            print_row(&sort_columns, i),
4586                            print_row(&sort_columns, j),
4587                            row_i,
4588                            row_j,
4589                            print_col_types(&sort_columns)
4590                        );
4591                    }
4592                }
4593
4594                // Validate rows length iterator
4595                {
4596                    let mut rows_iter = rows.iter();
4597                    let mut rows_lengths_iter = rows.lengths();
4598                    for (index, row) in rows_iter.by_ref().enumerate() {
4599                        let len = rows_lengths_iter
4600                            .next()
4601                            .expect("Reached end of length iterator while still have rows");
4602                        assert_eq!(
4603                            row.data.len(),
4604                            len,
4605                            "Row length mismatch: {} vs {}",
4606                            row.data.len(),
4607                            len
4608                        );
4609                        assert_eq!(
4610                            len,
4611                            rows.row_len(index),
4612                            "Row length mismatch at index {}: {} vs {}",
4613                            index,
4614                            len,
4615                            rows.row_len(index)
4616                        );
4617                    }
4618
4619                    assert_eq!(
4620                        rows_lengths_iter.next(),
4621                        None,
4622                        "Length iterator did not reach end"
4623                    );
4624                }
4625
4626                // Convert rows produced from convert_columns().
4627                // Note: validate_utf8 is set to false since Row is initialized through empty_rows()
4628                let back = converter.convert_rows(&rows).unwrap();
4629                for (actual, expected) in back.iter().zip(&arrays) {
4630                    actual.to_data().validate_full().unwrap();
4631                    dictionary_eq(actual, expected)
4632                }
4633
4634                // Check that we can convert rows into ByteArray and then parse, convert it back to array
4635                // Note: validate_utf8 is set to true since Row is initialized through RowParser
4636                let rows = rows.try_into_binary().expect("reasonable size");
4637                let parser = converter.parser();
4638                let back = converter
4639                    .convert_rows(rows.iter().map(|b| parser.parse(b.expect("valid bytes"))))
4640                    .unwrap();
4641                for (actual, expected) in back.iter().zip(&arrays) {
4642                    actual.to_data().validate_full().unwrap();
4643                    dictionary_eq(actual, expected)
4644                }
4645
4646                let rows = converter.from_binary(rows);
4647                let back = converter.convert_rows(&rows).unwrap();
4648                for (actual, expected) in back.iter().zip(&arrays) {
4649                    actual.to_data().validate_full().unwrap();
4650                    dictionary_eq(actual, expected)
4651                }
4652            }
4653        }
4654    }
4655
4656    fn replace_array_nulls(array: ArrayRef, new_nulls: Option<NullBuffer>) -> ArrayRef {
4657        make_array(
4658            array
4659                .into_data()
4660                .into_builder()
4661                // Replace the nulls
4662                .nulls(new_nulls)
4663                .build()
4664                .unwrap(),
4665        )
4666    }
4667
4668    fn assert_same_rows_when_changing_input_underlying_null_values(
4669        arrays: &[ArrayRef],
4670        converter: &RowConverter,
4671        rows: &Rows,
4672    ) {
4673        let arrays_with_different_data_behind_nulls = arrays
4674            .iter()
4675            .map(|arr| change_underline_null_values(arr))
4676            .collect::<Vec<_>>();
4677
4678        // Skip assertion if we did not change anything
4679        if arrays
4680            .iter()
4681            .zip(arrays_with_different_data_behind_nulls.iter())
4682            .all(|(a, b)| Arc::ptr_eq(a, b))
4683        {
4684            return;
4685        }
4686
4687        let rows_with_different_nulls = converter
4688            .convert_columns(&arrays_with_different_data_behind_nulls)
4689            .unwrap();
4690
4691        assert_eq!(
4692            rows.iter().collect::<Vec<_>>(),
4693            rows_with_different_nulls.iter().collect::<Vec<_>>(),
4694            "Different underlying nulls should not output different rows"
4695        )
4696    }
4697
4698    #[test]
4699    fn test_clear() {
4700        let converter = RowConverter::new(vec![SortField::new(DataType::Int32)]).unwrap();
4701        let mut rows = converter.empty_rows(3, 128);
4702
4703        let first = Int32Array::from(vec![None, Some(2), Some(4)]);
4704        let second = Int32Array::from(vec![Some(2), None, Some(4)]);
4705        let arrays = [Arc::new(first) as ArrayRef, Arc::new(second) as ArrayRef];
4706
4707        for array in arrays.iter() {
4708            rows.clear();
4709            converter
4710                .append(&mut rows, std::slice::from_ref(array))
4711                .unwrap();
4712            let back = converter.convert_rows(&rows).unwrap();
4713            assert_eq!(&back[0], array);
4714        }
4715
4716        let mut rows_expected = converter.empty_rows(3, 128);
4717        converter.append(&mut rows_expected, &arrays[1..]).unwrap();
4718
4719        for (i, (actual, expected)) in rows.iter().zip(rows_expected.iter()).enumerate() {
4720            assert_eq!(
4721                actual, expected,
4722                "For row {i}: expected {expected:?}, actual: {actual:?}",
4723            );
4724        }
4725    }
4726
4727    #[test]
4728    fn test_append_codec_dictionary_binary() {
4729        use DataType::*;
4730        // Dictionary RowConverter
4731        let converter = RowConverter::new(vec![SortField::new(Dictionary(
4732            Box::new(Int32),
4733            Box::new(Binary),
4734        ))])
4735        .unwrap();
4736        let mut rows = converter.empty_rows(4, 128);
4737
4738        let keys = Int32Array::from_iter_values([0, 1, 2, 3]);
4739        let values = BinaryArray::from(vec![
4740            Some("a".as_bytes()),
4741            Some(b"b"),
4742            Some(b"c"),
4743            Some(b"d"),
4744        ]);
4745        let dict_array = DictionaryArray::new(keys, Arc::new(values));
4746
4747        rows.clear();
4748        let array = Arc::new(dict_array) as ArrayRef;
4749        converter
4750            .append(&mut rows, std::slice::from_ref(&array))
4751            .unwrap();
4752        let back = converter.convert_rows(&rows).unwrap();
4753
4754        dictionary_eq(&back[0], &array);
4755    }
4756
4757    #[test]
4758    fn test_list_prefix() {
4759        let mut a = ListBuilder::new(Int8Builder::new());
4760        a.append_value([None]);
4761        a.append_value([None, None]);
4762        let a = a.finish();
4763
4764        let converter = RowConverter::new(vec![SortField::new(a.data_type().clone())]).unwrap();
4765        let rows = converter.convert_columns(&[Arc::new(a) as _]).unwrap();
4766        assert_eq!(rows.row(0).cmp(&rows.row(1)), Ordering::Less);
4767    }
4768
4769    #[test]
4770    fn map_should_be_marked_as_unsupported() {
4771        let map_data_type = Field::new_map(
4772            "map",
4773            "entries",
4774            Field::new("key", DataType::Utf8, false),
4775            Field::new("value", DataType::Utf8, true),
4776            false,
4777            true,
4778        )
4779        .data_type()
4780        .clone();
4781
4782        let is_supported = RowConverter::supports_fields(&[SortField::new(map_data_type)]);
4783
4784        assert!(!is_supported, "Map should not be supported");
4785    }
4786
4787    #[test]
4788    fn should_fail_to_create_row_converter_for_unsupported_map_type() {
4789        let map_data_type = Field::new_map(
4790            "map",
4791            "entries",
4792            Field::new("key", DataType::Utf8, false),
4793            Field::new("value", DataType::Utf8, true),
4794            false,
4795            true,
4796        )
4797        .data_type()
4798        .clone();
4799
4800        let converter = RowConverter::new(vec![SortField::new(map_data_type)]);
4801
4802        match converter {
4803            Err(ArrowError::NotYetImplemented(message)) => {
4804                assert!(
4805                    message.contains("Row format support not yet implemented for"),
4806                    "Expected NotYetImplemented error for map data type, got: {message}",
4807                );
4808            }
4809            Err(e) => panic!("Expected NotYetImplemented error, got: {e}"),
4810            Ok(_) => panic!("Expected NotYetImplemented error for map data type"),
4811        }
4812    }
4813
4814    #[test]
4815    fn test_values_buffer_smaller_when_utf8_validation_disabled() {
4816        fn get_values_buffer_len(col: ArrayRef) -> (usize, usize) {
4817            // 1. Convert cols into rows
4818            let converter = RowConverter::new(vec![SortField::new(DataType::Utf8View)]).unwrap();
4819
4820            // 2a. Convert rows into colsa (validate_utf8 = false)
4821            let rows = converter.convert_columns(&[col]).unwrap();
4822            let converted = converter.convert_rows(&rows).unwrap();
4823            let unchecked_values_len = converted[0].as_string_view().data_buffers()[0].len();
4824
4825            // 2b. Convert rows into cols (validate_utf8 = true since Row is initialized through RowParser)
4826            let rows = rows.try_into_binary().expect("reasonable size");
4827            let parser = converter.parser();
4828            let converted = converter
4829                .convert_rows(rows.iter().map(|b| parser.parse(b.expect("valid bytes"))))
4830                .unwrap();
4831            let checked_values_len = converted[0].as_string_view().data_buffers()[0].len();
4832            (unchecked_values_len, checked_values_len)
4833        }
4834
4835        // Case1. StringViewArray with inline strings
4836        let col = Arc::new(StringViewArray::from_iter([
4837            Some("hello"), // short(5)
4838            None,          // null
4839            Some("short"), // short(5)
4840            Some("tiny"),  // short(4)
4841        ])) as ArrayRef;
4842
4843        let (unchecked_values_len, checked_values_len) = get_values_buffer_len(col);
4844        // Since there are no long (>12) strings, len of values buffer is 0
4845        assert_eq!(unchecked_values_len, 0);
4846        // When utf8 validation enabled, values buffer includes inline strings (5+5+4)
4847        assert_eq!(checked_values_len, 14);
4848
4849        // Case2. StringViewArray with long(>12) strings
4850        let col = Arc::new(StringViewArray::from_iter([
4851            Some("this is a very long string over 12 bytes"),
4852            Some("another long string to test the buffer"),
4853        ])) as ArrayRef;
4854
4855        let (unchecked_values_len, checked_values_len) = get_values_buffer_len(col);
4856        // Since there are no inline strings, expected length of values buffer is the same
4857        assert!(unchecked_values_len > 0);
4858        assert_eq!(unchecked_values_len, checked_values_len);
4859
4860        // Case3. StringViewArray with both short and long strings
4861        let col = Arc::new(StringViewArray::from_iter([
4862            Some("tiny"),          // 4 (short)
4863            Some("thisisexact13"), // 13 (long)
4864            None,
4865            Some("short"), // 5 (short)
4866        ])) as ArrayRef;
4867
4868        let (unchecked_values_len, checked_values_len) = get_values_buffer_len(col);
4869        // Since there is single long string, len of values buffer is 13
4870        assert_eq!(unchecked_values_len, 13);
4871        assert!(checked_values_len > unchecked_values_len);
4872    }
4873
4874    #[test]
4875    fn test_sparse_union() {
4876        // create a sparse union with Int32 (type_id = 0) and Utf8 (type_id = 1)
4877        let int_array = Int32Array::from(vec![Some(1), None, Some(3), None, Some(5)]);
4878        let str_array = StringArray::from(vec![None, Some("b"), None, Some("d"), None]);
4879
4880        // [1, "b", 3, "d", 5]
4881        let type_ids = vec![0, 1, 0, 1, 0].into();
4882
4883        let union_fields = [
4884            (0, Arc::new(Field::new("int", DataType::Int32, false))),
4885            (1, Arc::new(Field::new("str", DataType::Utf8, false))),
4886        ]
4887        .into_iter()
4888        .collect();
4889
4890        let union_array = UnionArray::try_new(
4891            union_fields,
4892            type_ids,
4893            None,
4894            vec![Arc::new(int_array) as ArrayRef, Arc::new(str_array)],
4895        )
4896        .unwrap();
4897
4898        let union_type = union_array.data_type().clone();
4899        let converter = RowConverter::new(vec![SortField::new(union_type)]).unwrap();
4900
4901        let rows = converter
4902            .convert_columns(&[Arc::new(union_array.clone())])
4903            .unwrap();
4904
4905        // round trip
4906        let back = converter.convert_rows(&rows).unwrap();
4907        let back_union = back[0].as_any().downcast_ref::<UnionArray>().unwrap();
4908
4909        assert_eq!(union_array.len(), back_union.len());
4910        for i in 0..union_array.len() {
4911            assert_eq!(union_array.type_id(i), back_union.type_id(i));
4912        }
4913    }
4914
4915    #[test]
4916    fn test_sparse_union_with_nulls() {
4917        // create a sparse union with Int32 (type_id = 0) and Utf8 (type_id = 1)
4918        let int_array = Int32Array::from(vec![Some(1), None, Some(3), None, Some(5)]);
4919        let str_array = StringArray::from(vec![None::<&str>; 5]);
4920
4921        // [1, null (both children null), 3, null (both children null), 5]
4922        let type_ids = vec![0, 1, 0, 1, 0].into();
4923
4924        let union_fields = [
4925            (0, Arc::new(Field::new("int", DataType::Int32, true))),
4926            (1, Arc::new(Field::new("str", DataType::Utf8, true))),
4927        ]
4928        .into_iter()
4929        .collect();
4930
4931        let union_array = UnionArray::try_new(
4932            union_fields,
4933            type_ids,
4934            None,
4935            vec![Arc::new(int_array) as ArrayRef, Arc::new(str_array)],
4936        )
4937        .unwrap();
4938
4939        let union_type = union_array.data_type().clone();
4940        let converter = RowConverter::new(vec![SortField::new(union_type)]).unwrap();
4941
4942        let rows = converter
4943            .convert_columns(&[Arc::new(union_array.clone())])
4944            .unwrap();
4945
4946        // round trip
4947        let back = converter.convert_rows(&rows).unwrap();
4948        let back_union = back[0].as_any().downcast_ref::<UnionArray>().unwrap();
4949
4950        assert_eq!(union_array.len(), back_union.len());
4951        for i in 0..union_array.len() {
4952            let expected_null = union_array.is_null(i);
4953            let actual_null = back_union.is_null(i);
4954            assert_eq!(expected_null, actual_null, "Null mismatch at index {i}");
4955            if !expected_null {
4956                assert_eq!(union_array.type_id(i), back_union.type_id(i));
4957            }
4958        }
4959    }
4960
4961    #[test]
4962    fn test_dense_union() {
4963        // create a dense union with Int32 (type_id = 0) and use Utf8 (type_id = 1)
4964        let int_array = Int32Array::from(vec![1, 3, 5]);
4965        let str_array = StringArray::from(vec!["a", "b"]);
4966
4967        let type_ids = vec![0, 1, 0, 1, 0].into();
4968
4969        // [1, "a", 3, "b", 5]
4970        let offsets = vec![0, 0, 1, 1, 2].into();
4971
4972        let union_fields = [
4973            (0, Arc::new(Field::new("int", DataType::Int32, false))),
4974            (1, Arc::new(Field::new("str", DataType::Utf8, false))),
4975        ]
4976        .into_iter()
4977        .collect();
4978
4979        let union_array = UnionArray::try_new(
4980            union_fields,
4981            type_ids,
4982            Some(offsets), // Dense mode
4983            vec![Arc::new(int_array) as ArrayRef, Arc::new(str_array)],
4984        )
4985        .unwrap();
4986
4987        let union_type = union_array.data_type().clone();
4988        let converter = RowConverter::new(vec![SortField::new(union_type)]).unwrap();
4989
4990        let rows = converter
4991            .convert_columns(&[Arc::new(union_array.clone())])
4992            .unwrap();
4993
4994        // round trip
4995        let back = converter.convert_rows(&rows).unwrap();
4996        let back_union = back[0].as_any().downcast_ref::<UnionArray>().unwrap();
4997
4998        assert_eq!(union_array.len(), back_union.len());
4999        for i in 0..union_array.len() {
5000            assert_eq!(union_array.type_id(i), back_union.type_id(i));
5001        }
5002    }
5003
5004    #[test]
5005    fn test_dense_union_with_nulls() {
5006        // create a dense union with Int32 (type_id = 0) and Utf8 (type_id = 1)
5007        let int_array = Int32Array::from(vec![Some(1), None, Some(5)]);
5008        let str_array = StringArray::from(vec![Some("a"), None]);
5009
5010        // [1, "a", 5, null (str null), null (int null)]
5011        let type_ids = vec![0, 1, 0, 1, 0].into();
5012        let offsets = vec![0, 0, 1, 1, 2].into();
5013
5014        let union_fields = [
5015            (0, Arc::new(Field::new("int", DataType::Int32, true))),
5016            (1, Arc::new(Field::new("str", DataType::Utf8, true))),
5017        ]
5018        .into_iter()
5019        .collect();
5020
5021        let union_array = UnionArray::try_new(
5022            union_fields,
5023            type_ids,
5024            Some(offsets),
5025            vec![Arc::new(int_array) as ArrayRef, Arc::new(str_array)],
5026        )
5027        .unwrap();
5028
5029        let union_type = union_array.data_type().clone();
5030        let converter = RowConverter::new(vec![SortField::new(union_type)]).unwrap();
5031
5032        let rows = converter
5033            .convert_columns(&[Arc::new(union_array.clone())])
5034            .unwrap();
5035
5036        // round trip
5037        let back = converter.convert_rows(&rows).unwrap();
5038        let back_union = back[0].as_any().downcast_ref::<UnionArray>().unwrap();
5039
5040        assert_eq!(union_array.len(), back_union.len());
5041        for i in 0..union_array.len() {
5042            let expected_null = union_array.is_null(i);
5043            let actual_null = back_union.is_null(i);
5044            assert_eq!(expected_null, actual_null, "Null mismatch at index {i}");
5045            if !expected_null {
5046                assert_eq!(union_array.type_id(i), back_union.type_id(i));
5047            }
5048        }
5049    }
5050
5051    #[test]
5052    fn test_union_ordering() {
5053        let int_array = Int32Array::from(vec![100, 5, 20]);
5054        let str_array = StringArray::from(vec!["z", "a"]);
5055
5056        // [100, "z", 5, "a", 20]
5057        let type_ids = vec![0, 1, 0, 1, 0].into();
5058        let offsets = vec![0, 0, 1, 1, 2].into();
5059
5060        let union_fields = [
5061            (0, Arc::new(Field::new("int", DataType::Int32, false))),
5062            (1, Arc::new(Field::new("str", DataType::Utf8, false))),
5063        ]
5064        .into_iter()
5065        .collect();
5066
5067        let union_array = UnionArray::try_new(
5068            union_fields,
5069            type_ids,
5070            Some(offsets),
5071            vec![Arc::new(int_array) as ArrayRef, Arc::new(str_array)],
5072        )
5073        .unwrap();
5074
5075        let union_type = union_array.data_type().clone();
5076        let converter = RowConverter::new(vec![SortField::new(union_type)]).unwrap();
5077
5078        let rows = converter.convert_columns(&[Arc::new(union_array)]).unwrap();
5079
5080        /*
5081        expected ordering
5082
5083        row 2: 5    - type_id 0
5084        row 4: 20   - type_id 0
5085        row 0: 100  - type id 0
5086        row 3: "a"  - type id 1
5087        row 1: "z"  - type id 1
5088        */
5089
5090        // 5 < "z"
5091        assert!(rows.row(2) < rows.row(1));
5092
5093        // 100 < "a"
5094        assert!(rows.row(0) < rows.row(3));
5095
5096        // among ints
5097        // 5 < 20
5098        assert!(rows.row(2) < rows.row(4));
5099        // 20 < 100
5100        assert!(rows.row(4) < rows.row(0));
5101
5102        // among strigns
5103        // "a" < "z"
5104        assert!(rows.row(3) < rows.row(1));
5105    }
5106
5107    #[test]
5108    fn test_row_converter_roundtrip_with_many_union_columns() {
5109        // col 1: Union(Int32, Utf8) [67, "hello"]
5110        let fields1 = UnionFields::try_new(
5111            vec![0, 1],
5112            vec![
5113                Field::new("int", DataType::Int32, true),
5114                Field::new("string", DataType::Utf8, true),
5115            ],
5116        )
5117        .unwrap();
5118
5119        let int_array1 = Int32Array::from(vec![Some(67), None]);
5120        let string_array1 = StringArray::from(vec![None::<&str>, Some("hello")]);
5121        let type_ids1 = vec![0i8, 1].into();
5122
5123        let union_array1 = UnionArray::try_new(
5124            fields1.clone(),
5125            type_ids1,
5126            None,
5127            vec![
5128                Arc::new(int_array1) as ArrayRef,
5129                Arc::new(string_array1) as ArrayRef,
5130            ],
5131        )
5132        .unwrap();
5133
5134        // col 2: Union(Int32, Utf8) [100, "world"]
5135        let fields2 = UnionFields::try_new(
5136            vec![0, 1],
5137            vec![
5138                Field::new("int", DataType::Int32, true),
5139                Field::new("string", DataType::Utf8, true),
5140            ],
5141        )
5142        .unwrap();
5143
5144        let int_array2 = Int32Array::from(vec![Some(100), None]);
5145        let string_array2 = StringArray::from(vec![None::<&str>, Some("world")]);
5146        let type_ids2 = vec![0i8, 1].into();
5147
5148        let union_array2 = UnionArray::try_new(
5149            fields2.clone(),
5150            type_ids2,
5151            None,
5152            vec![
5153                Arc::new(int_array2) as ArrayRef,
5154                Arc::new(string_array2) as ArrayRef,
5155            ],
5156        )
5157        .unwrap();
5158
5159        // create a row converter with 2 union columns
5160        let field1 = Field::new("col1", DataType::Union(fields1, UnionMode::Sparse), true);
5161        let field2 = Field::new("col2", DataType::Union(fields2, UnionMode::Sparse), true);
5162
5163        let sort_field1 = SortField::new(field1.data_type().clone());
5164        let sort_field2 = SortField::new(field2.data_type().clone());
5165
5166        let converter = RowConverter::new(vec![sort_field1, sort_field2]).unwrap();
5167
5168        let rows = converter
5169            .convert_columns(&[
5170                Arc::new(union_array1.clone()) as ArrayRef,
5171                Arc::new(union_array2.clone()) as ArrayRef,
5172            ])
5173            .unwrap();
5174
5175        // roundtrip
5176        let out = converter.convert_rows(&rows).unwrap();
5177
5178        let [col1, col2] = out.as_slice() else {
5179            panic!("expected 2 columns")
5180        };
5181
5182        let col1 = col1.as_any().downcast_ref::<UnionArray>().unwrap();
5183        let col2 = col2.as_any().downcast_ref::<UnionArray>().unwrap();
5184
5185        for (expected, got) in [union_array1, union_array2].iter().zip([col1, col2]) {
5186            assert_eq!(expected.len(), got.len());
5187            assert_eq!(expected.type_ids(), got.type_ids());
5188
5189            for i in 0..expected.len() {
5190                assert_eq!(expected.value(i).as_ref(), got.value(i).as_ref());
5191            }
5192        }
5193    }
5194
5195    #[test]
5196    fn test_row_converter_roundtrip_with_one_union_column() {
5197        let fields = UnionFields::try_new(
5198            vec![0, 1],
5199            vec![
5200                Field::new("int", DataType::Int32, true),
5201                Field::new("string", DataType::Utf8, true),
5202            ],
5203        )
5204        .unwrap();
5205
5206        let int_array = Int32Array::from(vec![Some(67), None]);
5207        let string_array = StringArray::from(vec![None::<&str>, Some("hello")]);
5208        let type_ids = vec![0i8, 1].into();
5209
5210        let union_array = UnionArray::try_new(
5211            fields.clone(),
5212            type_ids,
5213            None,
5214            vec![
5215                Arc::new(int_array) as ArrayRef,
5216                Arc::new(string_array) as ArrayRef,
5217            ],
5218        )
5219        .unwrap();
5220
5221        let field = Field::new("col", DataType::Union(fields, UnionMode::Sparse), true);
5222        let sort_field = SortField::new(field.data_type().clone());
5223        let converter = RowConverter::new(vec![sort_field]).unwrap();
5224
5225        let rows = converter
5226            .convert_columns(&[Arc::new(union_array.clone()) as ArrayRef])
5227            .unwrap();
5228
5229        // roundtrip
5230        let out = converter.convert_rows(&rows).unwrap();
5231
5232        let [col1] = out.as_slice() else {
5233            panic!("expected 1 column")
5234        };
5235
5236        let col = col1.as_any().downcast_ref::<UnionArray>().unwrap();
5237        assert_eq!(col.len(), union_array.len());
5238        assert_eq!(col.type_ids(), union_array.type_ids());
5239
5240        for i in 0..col.len() {
5241            assert_eq!(col.value(i).as_ref(), union_array.value(i).as_ref());
5242        }
5243    }
5244
5245    #[test]
5246    fn test_row_converter_roundtrip_with_non_default_union_type_ids() {
5247        // test with non-sequential type IDs (70, 85) instead of (0, 1)
5248        let fields = UnionFields::try_new(
5249            vec![70, 85],
5250            vec![
5251                Field::new("int", DataType::Int32, true),
5252                Field::new("string", DataType::Utf8, true),
5253            ],
5254        )
5255        .unwrap();
5256
5257        let int_array = Int32Array::from(vec![Some(67), None]);
5258        let string_array = StringArray::from(vec![None::<&str>, Some("hello")]);
5259        let type_ids = vec![70i8, 85].into();
5260
5261        let union_array = UnionArray::try_new(
5262            fields.clone(),
5263            type_ids,
5264            None,
5265            vec![
5266                Arc::new(int_array) as ArrayRef,
5267                Arc::new(string_array) as ArrayRef,
5268            ],
5269        )
5270        .unwrap();
5271
5272        let field = Field::new("col", DataType::Union(fields, UnionMode::Sparse), true);
5273        let sort_field = SortField::new(field.data_type().clone());
5274        let converter = RowConverter::new(vec![sort_field]).unwrap();
5275
5276        let rows = converter
5277            .convert_columns(&[Arc::new(union_array.clone()) as ArrayRef])
5278            .unwrap();
5279
5280        // roundtrip
5281        let out = converter.convert_rows(&rows).unwrap();
5282
5283        let [col1] = out.as_slice() else {
5284            panic!("expected 1 column")
5285        };
5286
5287        let col = col1.as_any().downcast_ref::<UnionArray>().unwrap();
5288        assert_eq!(col.len(), union_array.len());
5289        assert_eq!(col.type_ids(), union_array.type_ids());
5290
5291        for i in 0..col.len() {
5292            assert_eq!(col.value(i).as_ref(), union_array.value(i).as_ref());
5293        }
5294    }
5295
5296    #[test]
5297    fn rows_size_should_count_for_capacity() {
5298        let row_converter = RowConverter::new(vec![SortField::new(DataType::UInt8)]).unwrap();
5299
5300        let empty_rows_size_with_preallocate_rows_and_data = {
5301            let rows = row_converter.empty_rows(1000, 1000);
5302
5303            rows.size()
5304        };
5305        let empty_rows_size_with_preallocate_rows = {
5306            let rows = row_converter.empty_rows(1000, 0);
5307
5308            rows.size()
5309        };
5310        let empty_rows_size_with_preallocate_data = {
5311            let rows = row_converter.empty_rows(0, 1000);
5312
5313            rows.size()
5314        };
5315        let empty_rows_size_without_preallocate = {
5316            let rows = row_converter.empty_rows(0, 0);
5317
5318            rows.size()
5319        };
5320
5321        assert!(
5322            empty_rows_size_with_preallocate_rows_and_data > empty_rows_size_with_preallocate_rows,
5323            "{empty_rows_size_with_preallocate_rows_and_data} should be larger than {empty_rows_size_with_preallocate_rows}"
5324        );
5325        assert!(
5326            empty_rows_size_with_preallocate_rows_and_data > empty_rows_size_with_preallocate_data,
5327            "{empty_rows_size_with_preallocate_rows_and_data} should be larger than {empty_rows_size_with_preallocate_data}"
5328        );
5329        assert!(
5330            empty_rows_size_with_preallocate_rows > empty_rows_size_without_preallocate,
5331            "{empty_rows_size_with_preallocate_rows} should be larger than {empty_rows_size_without_preallocate}"
5332        );
5333        assert!(
5334            empty_rows_size_with_preallocate_data > empty_rows_size_without_preallocate,
5335            "{empty_rows_size_with_preallocate_data} should be larger than {empty_rows_size_without_preallocate}"
5336        );
5337    }
5338
5339    #[test]
5340    fn test_struct_no_child_fields() {
5341        fn run_test(array: ArrayRef) {
5342            let sort_fields = vec![SortField::new(array.data_type().clone())];
5343            let converter = RowConverter::new(sort_fields).unwrap();
5344            let r = converter.convert_columns(&[Arc::clone(&array)]).unwrap();
5345
5346            let back = converter.convert_rows(&r).unwrap();
5347            assert_eq!(back.len(), 1);
5348            assert_eq!(&back[0], &array);
5349        }
5350
5351        let s = Arc::new(StructArray::new_empty_fields(5, None)) as ArrayRef;
5352        run_test(s);
5353
5354        let s = Arc::new(StructArray::new_empty_fields(
5355            5,
5356            Some(vec![true, false, true, false, false].into()),
5357        )) as ArrayRef;
5358        run_test(s);
5359    }
5360
5361    #[test]
5362    fn reserve_should_increase_capacity_to_the_requested_size() {
5363        let row_converter = RowConverter::new(vec![SortField::new(DataType::UInt8)]).unwrap();
5364        let mut empty_rows = row_converter.empty_rows(0, 0);
5365        empty_rows.reserve(50, 50);
5366        let before_size = empty_rows.size();
5367        empty_rows.reserve(50, 50);
5368        assert_eq!(
5369            empty_rows.size(),
5370            before_size,
5371            "Size should not change when reserving already reserved space"
5372        );
5373        empty_rows.reserve(10, 20);
5374        assert_eq!(
5375            empty_rows.size(),
5376            before_size,
5377            "Size should not change when already have space for the expected reserved data"
5378        );
5379
5380        empty_rows.reserve(100, 20);
5381        assert!(
5382            empty_rows.size() > before_size,
5383            "Size should increase when reserving more space than previously reserved"
5384        );
5385
5386        let before_size = empty_rows.size();
5387
5388        empty_rows.reserve(20, 100);
5389        assert!(
5390            empty_rows.size() > before_size,
5391            "Size should increase when reserving more space than previously reserved"
5392        );
5393    }
5394
5395    #[test]
5396    fn empty_rows_should_return_empty_lengths_iterator() {
5397        let rows = RowConverter::new(vec![SortField::new(DataType::UInt8)])
5398            .unwrap()
5399            .empty_rows(0, 0);
5400        let mut lengths_iter = rows.lengths();
5401        assert_eq!(lengths_iter.next(), None);
5402    }
5403
5404    #[test]
5405    fn test_nested_null_list() {
5406        let null_array = Arc::new(NullArray::new(3));
5407        // [[NULL], [], [NULL, NULL]]
5408        let list: ArrayRef = Arc::new(ListArray::new(
5409            Field::new_list_field(DataType::Null, true).into(),
5410            OffsetBuffer::from_lengths(vec![1, 0, 2]),
5411            null_array,
5412            None,
5413        ));
5414
5415        let converter = RowConverter::new(vec![SortField::new(list.data_type().clone())]).unwrap();
5416        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5417        let back = converter.convert_rows(&rows).unwrap();
5418
5419        assert_eq!(&list, &back[0]);
5420    }
5421
5422    // Test case from original issue #9227: [[NULL]] - double nested List with Null
5423    #[test]
5424    fn test_double_nested_null_list() {
5425        let null_array = Arc::new(NullArray::new(1));
5426        // [NULL]
5427        let nested_field = Arc::new(Field::new_list_field(DataType::Null, true));
5428        let nested_list = Arc::new(ListArray::new(
5429            nested_field.clone(),
5430            OffsetBuffer::from_lengths(vec![1]),
5431            null_array,
5432            None,
5433        ));
5434        // [[NULL]]
5435        let list = Arc::new(ListArray::new(
5436            Field::new_list_field(DataType::List(nested_field), true).into(),
5437            OffsetBuffer::from_lengths(vec![1]),
5438            nested_list,
5439            None,
5440        )) as ArrayRef;
5441
5442        let converter = RowConverter::new(vec![SortField::new(list.data_type().clone())]).unwrap();
5443        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5444        let back = converter.convert_rows(&rows).unwrap();
5445
5446        assert_eq!(&list, &back[0]);
5447    }
5448
5449    // Test LargeList<Null>
5450    #[test]
5451    fn test_large_list_null() {
5452        let null_array = Arc::new(NullArray::new(3));
5453        // [[NULL], [], [NULL, NULL]] as LargeList
5454        let list: ArrayRef = Arc::new(LargeListArray::new(
5455            Field::new_list_field(DataType::Null, true).into(),
5456            OffsetBuffer::from_lengths(vec![1, 0, 2]),
5457            null_array,
5458            None,
5459        ));
5460
5461        let converter = RowConverter::new(vec![SortField::new(list.data_type().clone())]).unwrap();
5462        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5463        let back = converter.convert_rows(&rows).unwrap();
5464
5465        assert_eq!(&list, &back[0]);
5466    }
5467
5468    // Test FixedSizeList<Null>
5469    #[test]
5470    fn test_fixed_size_list_null() {
5471        let null_array = Arc::new(NullArray::new(6));
5472        // [[NULL, NULL], [NULL, NULL], [NULL, NULL]] as FixedSizeList
5473        let list: ArrayRef = Arc::new(FixedSizeListArray::new(
5474            Arc::new(Field::new_list_field(DataType::Null, true)),
5475            2,
5476            null_array,
5477            None,
5478        ));
5479
5480        let converter = RowConverter::new(vec![SortField::new(list.data_type().clone())]).unwrap();
5481        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5482        let back = converter.convert_rows(&rows).unwrap();
5483
5484        assert_eq!(&list, &back[0]);
5485    }
5486
5487    // Test List<Null> with various combinations of nulls and empty lists
5488    #[test]
5489    fn test_list_null_variations() {
5490        // Test case: [[NULL], [], [NULL, NULL]]
5491        let null_array = Arc::new(NullArray::new(3));
5492        let list: ArrayRef = Arc::new(ListArray::new(
5493            Field::new_list_field(DataType::Null, true).into(),
5494            OffsetBuffer::from_lengths(vec![1, 0, 2]),
5495            null_array,
5496            None,
5497        ));
5498
5499        let converter = RowConverter::new(vec![SortField::new(list.data_type().clone())]).unwrap();
5500        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5501        let back = converter.convert_rows(&rows).unwrap();
5502        assert_eq!(&list, &back[0]);
5503
5504        // Test case: [[NULL], null, [NULL, NULL]] - middle element is null
5505        let null_array = Arc::new(NullArray::new(3));
5506        let list: ArrayRef = Arc::new(ListArray::new(
5507            Field::new_list_field(DataType::Null, true).into(),
5508            OffsetBuffer::from_lengths(vec![1, 0, 2]),
5509            null_array,
5510            Some(vec![true, false, true].into()),
5511        ));
5512
5513        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5514        let back = converter.convert_rows(&rows).unwrap();
5515        assert_eq!(&list, &back[0]);
5516
5517        // Test case: [] - empty list
5518        let null_array = Arc::new(NullArray::new(0));
5519        let list: ArrayRef = Arc::new(ListArray::new(
5520            Field::new_list_field(DataType::Null, true).into(),
5521            OffsetBuffer::from_lengths(vec![]),
5522            null_array,
5523            None,
5524        ));
5525
5526        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5527        let back = converter.convert_rows(&rows).unwrap();
5528        assert_eq!(&list, &back[0]);
5529
5530        // Test case: [[], [], []] - all empty sublists
5531        let null_array = Arc::new(NullArray::new(0));
5532        let list: ArrayRef = Arc::new(ListArray::new(
5533            Field::new_list_field(DataType::Null, true).into(),
5534            OffsetBuffer::from_lengths(vec![0, 0, 0]),
5535            null_array,
5536            None,
5537        ));
5538
5539        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5540        let back = converter.convert_rows(&rows).unwrap();
5541        assert_eq!(&list, &back[0]);
5542    }
5543
5544    // Test List<Null> with descending order
5545    #[test]
5546    fn test_list_null_descending() {
5547        let null_array = Arc::new(NullArray::new(3));
5548        // [[NULL], [], [NULL, NULL]]
5549        let list: ArrayRef = Arc::new(ListArray::new(
5550            Field::new_list_field(DataType::Null, true).into(),
5551            OffsetBuffer::from_lengths(vec![1, 0, 2]),
5552            null_array,
5553            None,
5554        ));
5555
5556        let options = SortOptions::default().with_descending(true);
5557        let field = SortField::new_with_options(list.data_type().clone(), options);
5558        let converter = RowConverter::new(vec![field]).unwrap();
5559        let rows = converter.convert_columns(&[Arc::clone(&list)]).unwrap();
5560        let back = converter.convert_rows(&rows).unwrap();
5561
5562        assert_eq!(&list, &back[0]);
5563    }
5564
5565    // Test Struct with Null field
5566    #[test]
5567    fn test_struct_with_null_field() {
5568        // Struct { a: Null, b: Int32 }
5569        let null_array = Arc::new(NullArray::new(3));
5570        let int_array = Arc::new(Int32Array::from(vec![1, 2, 3]));
5571
5572        let struct_array: ArrayRef = Arc::new(StructArray::new(
5573            vec![
5574                Arc::new(Field::new("a", DataType::Null, true)),
5575                Arc::new(Field::new("b", DataType::Int32, true)),
5576            ]
5577            .into(),
5578            vec![null_array, int_array],
5579            Some(vec![true, true, false].into()), // validity bitmap
5580        ));
5581
5582        let converter =
5583            RowConverter::new(vec![SortField::new(struct_array.data_type().clone())]).unwrap();
5584        let rows = converter
5585            .convert_columns(&[Arc::clone(&struct_array)])
5586            .unwrap();
5587        let back = converter.convert_rows(&rows).unwrap();
5588
5589        assert_eq!(&struct_array, &back[0]);
5590    }
5591
5592    // Test nested Struct with Null
5593    #[test]
5594    fn test_nested_struct_with_null() {
5595        // Inner struct: { x: Null }
5596        let inner_null = Arc::new(NullArray::new(2));
5597        let inner_struct = Arc::new(StructArray::new(
5598            vec![Arc::new(Field::new("x", DataType::Null, true))].into(),
5599            vec![inner_null],
5600            None,
5601        ));
5602
5603        // Outer struct: { inner: Struct { x: Null }, y: Int32 }
5604        let y_array = Arc::new(Int32Array::from(vec![10, 20]));
5605        let outer_struct: ArrayRef = Arc::new(StructArray::new(
5606            vec![
5607                Arc::new(Field::new("inner", inner_struct.data_type().clone(), true)),
5608                Arc::new(Field::new("y", DataType::Int32, true)),
5609            ]
5610            .into(),
5611            vec![inner_struct, y_array],
5612            None,
5613        ));
5614
5615        let converter =
5616            RowConverter::new(vec![SortField::new(outer_struct.data_type().clone())]).unwrap();
5617        let rows = converter
5618            .convert_columns(&[Arc::clone(&outer_struct)])
5619            .unwrap();
5620        let back = converter.convert_rows(&rows).unwrap();
5621
5622        assert_eq!(&outer_struct, &back[0]);
5623    }
5624
5625    // Test Map<Null> - verify it's not supported (as per current implementation)
5626    // https://github.com/apache/arrow-rs/issues/7879
5627    #[test]
5628    fn test_map_null_not_supported() {
5629        // Map with Null values
5630        let map_data_type = Field::new_map(
5631            "map",
5632            "entries",
5633            Field::new("key", DataType::Utf8, false),
5634            Field::new("value", DataType::Null, true),
5635            false,
5636            true,
5637        )
5638        .data_type()
5639        .clone();
5640
5641        // Currently Map is not supported by RowConverter
5642        let result = RowConverter::new(vec![SortField::new(map_data_type)]);
5643        assert!(
5644            result.is_err(),
5645            "Map should not be supported by RowConverter"
5646        );
5647        assert!(
5648            result
5649                .unwrap_err()
5650                .to_string()
5651                .contains("not yet implemented")
5652        );
5653    }
5654}