1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! Comparison kernels for `Array`s.
//!
//! These kernels can leverage SIMD if available on your system.  Currently no runtime
//! detection is provided, you should enable the specific SIMD intrinsics using
//! `RUSTFLAGS="-C target-feature=+avx2"` for example.  See the documentation
//! [here](https://doc.rust-lang.org/stable/core/arch/) for more information.
//!

use arrow_array::cast::AsArray;
use arrow_array::types::ByteArrayType;
use arrow_array::{
    downcast_primitive_array, AnyDictionaryArray, Array, ArrowNativeTypeOp, BooleanArray, Datum,
    FixedSizeBinaryArray, GenericByteArray,
};
use arrow_buffer::bit_util::ceil;
use arrow_buffer::{BooleanBuffer, MutableBuffer, NullBuffer};
use arrow_schema::ArrowError;
use arrow_select::take::take;
use std::ops::Not;

#[derive(Debug, Copy, Clone)]
enum Op {
    Equal,
    NotEqual,
    Less,
    LessEqual,
    Greater,
    GreaterEqual,
    Distinct,
    NotDistinct,
}

impl std::fmt::Display for Op {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Op::Equal => write!(f, "=="),
            Op::NotEqual => write!(f, "!="),
            Op::Less => write!(f, "<"),
            Op::LessEqual => write!(f, "<="),
            Op::Greater => write!(f, ">"),
            Op::GreaterEqual => write!(f, ">="),
            Op::Distinct => write!(f, "IS DISTINCT FROM"),
            Op::NotDistinct => write!(f, "IS NOT DISTINCT FROM"),
        }
    }
}

/// Perform `left == right` operation on two [`Datum`]
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn eq(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::Equal, lhs, rhs)
}

/// Perform `left != right` operation on two [`Datum`]
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn neq(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::NotEqual, lhs, rhs)
}

/// Perform `left < right` operation on two [`Datum`]
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn lt(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::Less, lhs, rhs)
}

/// Perform `left <= right` operation on two [`Datum`]
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn lt_eq(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::LessEqual, lhs, rhs)
}

/// Perform `left > right` operation on two [`Datum`]
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn gt(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::Greater, lhs, rhs)
}

/// Perform `left >= right` operation on two [`Datum`]
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn gt_eq(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::GreaterEqual, lhs, rhs)
}

/// Perform `left IS DISTINCT FROM right` operation on two [`Datum`]
///
/// [`distinct`] is similar to [`neq`], only differing in null handling. In particular, two
/// operands are considered DISTINCT if they have a different value or if one of them is NULL
/// and the other isn't. The result of [`distinct`] is never NULL.
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn distinct(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::Distinct, lhs, rhs)
}

/// Perform `left IS NOT DISTINCT FROM right` operation on two [`Datum`]
///
/// [`not_distinct`] is similar to [`eq`], only differing in null handling. In particular, two
/// operands are considered `NOT DISTINCT` if they have the same value or if both of them
/// is NULL. The result of [`not_distinct`] is never NULL.
///
/// For floating values like f32 and f64, this comparison produces an ordering in accordance to
/// the totalOrder predicate as defined in the IEEE 754 (2008 revision) floating point standard.
/// Note that totalOrder treats positive and negative zeros as different. If it is necessary
/// to treat them as equal, please normalize zeros before calling this kernel.
///
/// Please refer to [`f32::total_cmp`] and [`f64::total_cmp`]
pub fn not_distinct(lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    compare_op(Op::NotDistinct, lhs, rhs)
}

/// Perform `op` on the provided `Datum`
#[inline(never)]
fn compare_op(op: Op, lhs: &dyn Datum, rhs: &dyn Datum) -> Result<BooleanArray, ArrowError> {
    use arrow_schema::DataType::*;
    let (l, l_s) = lhs.get();
    let (r, r_s) = rhs.get();

    let l_len = l.len();
    let r_len = r.len();

    if l_len != r_len && !l_s && !r_s {
        return Err(ArrowError::InvalidArgumentError(format!(
            "Cannot compare arrays of different lengths, got {l_len} vs {r_len}"
        )));
    }

    let len = match l_s {
        true => r_len,
        false => l_len,
    };

    let l_nulls = l.logical_nulls();
    let r_nulls = r.logical_nulls();

    let l_v = l.as_any_dictionary_opt();
    let l = l_v.map(|x| x.values().as_ref()).unwrap_or(l);
    let l_t = l.data_type();

    let r_v = r.as_any_dictionary_opt();
    let r = r_v.map(|x| x.values().as_ref()).unwrap_or(r);
    let r_t = r.data_type();

    if l_t != r_t || l_t.is_nested() {
        return Err(ArrowError::InvalidArgumentError(format!(
            "Invalid comparison operation: {l_t} {op} {r_t}"
        )));
    }

    // Defer computation as may not be necessary
    let values = || -> BooleanBuffer {
        let d = downcast_primitive_array! {
            (l, r) => apply(op, l.values().as_ref(), l_s, l_v, r.values().as_ref(), r_s, r_v),
            (Boolean, Boolean) => apply(op, l.as_boolean(), l_s, l_v, r.as_boolean(), r_s, r_v),
            (Utf8, Utf8) => apply(op, l.as_string::<i32>(), l_s, l_v, r.as_string::<i32>(), r_s, r_v),
            (LargeUtf8, LargeUtf8) => apply(op, l.as_string::<i64>(), l_s, l_v, r.as_string::<i64>(), r_s, r_v),
            (Binary, Binary) => apply(op, l.as_binary::<i32>(), l_s, l_v, r.as_binary::<i32>(), r_s, r_v),
            (LargeBinary, LargeBinary) => apply(op, l.as_binary::<i64>(), l_s, l_v, r.as_binary::<i64>(), r_s, r_v),
            (FixedSizeBinary(_), FixedSizeBinary(_)) => apply(op, l.as_fixed_size_binary(), l_s, l_v, r.as_fixed_size_binary(), r_s, r_v),
            (Null, Null) => None,
            _ => unreachable!(),
        };
        d.unwrap_or_else(|| BooleanBuffer::new_unset(len))
    };

    let l_nulls = l_nulls.filter(|n| n.null_count() > 0);
    let r_nulls = r_nulls.filter(|n| n.null_count() > 0);
    Ok(match (l_nulls, l_s, r_nulls, r_s) {
        (Some(l), true, Some(r), true) | (Some(l), false, Some(r), false) => {
            // Either both sides are scalar or neither side is scalar
            match op {
                Op::Distinct => {
                    let values = values();
                    let l = l.inner().bit_chunks().iter_padded();
                    let r = r.inner().bit_chunks().iter_padded();
                    let ne = values.bit_chunks().iter_padded();

                    let c = |((l, r), n)| ((l ^ r) | (l & r & n));
                    let buffer = l.zip(r).zip(ne).map(c).collect();
                    BooleanBuffer::new(buffer, 0, len).into()
                }
                Op::NotDistinct => {
                    let values = values();
                    let l = l.inner().bit_chunks().iter_padded();
                    let r = r.inner().bit_chunks().iter_padded();
                    let e = values.bit_chunks().iter_padded();

                    let c = |((l, r), e)| u64::not(l | r) | (l & r & e);
                    let buffer = l.zip(r).zip(e).map(c).collect();
                    BooleanBuffer::new(buffer, 0, len).into()
                }
                _ => BooleanArray::new(values(), NullBuffer::union(Some(&l), Some(&r))),
            }
        }
        (Some(_), true, Some(a), false) | (Some(a), false, Some(_), true) => {
            // Scalar is null, other side is non-scalar and nullable
            match op {
                Op::Distinct => a.into_inner().into(),
                Op::NotDistinct => a.into_inner().not().into(),
                _ => BooleanArray::new_null(len),
            }
        }
        (Some(nulls), is_scalar, None, _) | (None, _, Some(nulls), is_scalar) => {
            // Only one side is nullable
            match is_scalar {
                true => match op {
                    // Scalar is null, other side is not nullable
                    Op::Distinct => BooleanBuffer::new_set(len).into(),
                    Op::NotDistinct => BooleanBuffer::new_unset(len).into(),
                    _ => BooleanArray::new_null(len),
                },
                false => match op {
                    Op::Distinct => {
                        let values = values();
                        let l = nulls.inner().bit_chunks().iter_padded();
                        let ne = values.bit_chunks().iter_padded();
                        let c = |(l, n)| u64::not(l) | n;
                        let buffer = l.zip(ne).map(c).collect();
                        BooleanBuffer::new(buffer, 0, len).into()
                    }
                    Op::NotDistinct => (nulls.inner() & &values()).into(),
                    _ => BooleanArray::new(values(), Some(nulls)),
                },
            }
        }
        // Neither side is nullable
        (None, _, None, _) => BooleanArray::new(values(), None),
    })
}

/// Perform a potentially vectored `op` on the provided `ArrayOrd`
fn apply<T: ArrayOrd>(
    op: Op,
    l: T,
    l_s: bool,
    l_v: Option<&dyn AnyDictionaryArray>,
    r: T,
    r_s: bool,
    r_v: Option<&dyn AnyDictionaryArray>,
) -> Option<BooleanBuffer> {
    if l.len() == 0 || r.len() == 0 {
        return None; // Handle empty dictionaries
    }

    if !l_s && !r_s && (l_v.is_some() || r_v.is_some()) {
        // Not scalar and at least one side has a dictionary, need to perform vectored comparison
        let l_v = l_v
            .map(|x| x.normalized_keys())
            .unwrap_or_else(|| (0..l.len()).collect());

        let r_v = r_v
            .map(|x| x.normalized_keys())
            .unwrap_or_else(|| (0..r.len()).collect());

        assert_eq!(l_v.len(), r_v.len()); // Sanity check

        Some(match op {
            Op::Equal | Op::NotDistinct => apply_op_vectored(l, &l_v, r, &r_v, false, T::is_eq),
            Op::NotEqual | Op::Distinct => apply_op_vectored(l, &l_v, r, &r_v, true, T::is_eq),
            Op::Less => apply_op_vectored(l, &l_v, r, &r_v, false, T::is_lt),
            Op::LessEqual => apply_op_vectored(r, &r_v, l, &l_v, true, T::is_lt),
            Op::Greater => apply_op_vectored(r, &r_v, l, &l_v, false, T::is_lt),
            Op::GreaterEqual => apply_op_vectored(l, &l_v, r, &r_v, true, T::is_lt),
        })
    } else {
        let l_s = l_s.then(|| l_v.map(|x| x.normalized_keys()[0]).unwrap_or_default());
        let r_s = r_s.then(|| r_v.map(|x| x.normalized_keys()[0]).unwrap_or_default());

        let buffer = match op {
            Op::Equal | Op::NotDistinct => apply_op(l, l_s, r, r_s, false, T::is_eq),
            Op::NotEqual | Op::Distinct => apply_op(l, l_s, r, r_s, true, T::is_eq),
            Op::Less => apply_op(l, l_s, r, r_s, false, T::is_lt),
            Op::LessEqual => apply_op(r, r_s, l, l_s, true, T::is_lt),
            Op::Greater => apply_op(r, r_s, l, l_s, false, T::is_lt),
            Op::GreaterEqual => apply_op(l, l_s, r, r_s, true, T::is_lt),
        };

        // If a side had a dictionary, and was not scalar, we need to materialize this
        Some(match (l_v, r_v) {
            (Some(l_v), _) if l_s.is_none() => take_bits(l_v, buffer),
            (_, Some(r_v)) if r_s.is_none() => take_bits(r_v, buffer),
            _ => buffer,
        })
    }
}

/// Perform a take operation on `buffer` with the given dictionary
fn take_bits(v: &dyn AnyDictionaryArray, buffer: BooleanBuffer) -> BooleanBuffer {
    let array = take(&BooleanArray::new(buffer, None), v.keys(), None).unwrap();
    array.as_boolean().values().clone()
}

/// Invokes `f` with values `0..len` collecting the boolean results into a new `BooleanBuffer`
///
/// This is similar to [`MutableBuffer::collect_bool`] but with
/// the option to efficiently negate the result
fn collect_bool(len: usize, neg: bool, f: impl Fn(usize) -> bool) -> BooleanBuffer {
    let mut buffer = MutableBuffer::new(ceil(len, 64) * 8);

    let chunks = len / 64;
    let remainder = len % 64;
    for chunk in 0..chunks {
        let mut packed = 0;
        for bit_idx in 0..64 {
            let i = bit_idx + chunk * 64;
            packed |= (f(i) as u64) << bit_idx;
        }
        if neg {
            packed = !packed
        }

        // SAFETY: Already allocated sufficient capacity
        unsafe { buffer.push_unchecked(packed) }
    }

    if remainder != 0 {
        let mut packed = 0;
        for bit_idx in 0..remainder {
            let i = bit_idx + chunks * 64;
            packed |= (f(i) as u64) << bit_idx;
        }
        if neg {
            packed = !packed
        }

        // SAFETY: Already allocated sufficient capacity
        unsafe { buffer.push_unchecked(packed) }
    }
    BooleanBuffer::new(buffer.into(), 0, len)
}

/// Applies `op` to possibly scalar `ArrayOrd`
///
/// If l is scalar `l_s` will be `Some(idx)` where `idx` is the index of the scalar value in `l`
/// If r is scalar `r_s` will be `Some(idx)` where `idx` is the index of the scalar value in `r`
///
/// If `neg` is true the result of `op` will be negated
fn apply_op<T: ArrayOrd>(
    l: T,
    l_s: Option<usize>,
    r: T,
    r_s: Option<usize>,
    neg: bool,
    op: impl Fn(T::Item, T::Item) -> bool,
) -> BooleanBuffer {
    match (l_s, r_s) {
        (None, None) => {
            assert_eq!(l.len(), r.len());
            collect_bool(l.len(), neg, |idx| unsafe {
                op(l.value_unchecked(idx), r.value_unchecked(idx))
            })
        }
        (Some(l_s), Some(r_s)) => {
            let a = l.value(l_s);
            let b = r.value(r_s);
            std::iter::once(op(a, b) ^ neg).collect()
        }
        (Some(l_s), None) => {
            let v = l.value(l_s);
            collect_bool(r.len(), neg, |idx| op(v, unsafe { r.value_unchecked(idx) }))
        }
        (None, Some(r_s)) => {
            let v = r.value(r_s);
            collect_bool(l.len(), neg, |idx| op(unsafe { l.value_unchecked(idx) }, v))
        }
    }
}

/// Applies `op` to possibly scalar `ArrayOrd` with the given indices
fn apply_op_vectored<T: ArrayOrd>(
    l: T,
    l_v: &[usize],
    r: T,
    r_v: &[usize],
    neg: bool,
    op: impl Fn(T::Item, T::Item) -> bool,
) -> BooleanBuffer {
    assert_eq!(l_v.len(), r_v.len());
    collect_bool(l_v.len(), neg, |idx| unsafe {
        let l_idx = *l_v.get_unchecked(idx);
        let r_idx = *r_v.get_unchecked(idx);
        op(l.value_unchecked(l_idx), r.value_unchecked(r_idx))
    })
}

trait ArrayOrd {
    type Item: Copy + Default;

    fn len(&self) -> usize;

    fn value(&self, idx: usize) -> Self::Item {
        assert!(idx < self.len());
        unsafe { self.value_unchecked(idx) }
    }

    /// # Safety
    ///
    /// Safe if `idx < self.len()`
    unsafe fn value_unchecked(&self, idx: usize) -> Self::Item;

    fn is_eq(l: Self::Item, r: Self::Item) -> bool;

    fn is_lt(l: Self::Item, r: Self::Item) -> bool;
}

impl<'a> ArrayOrd for &'a BooleanArray {
    type Item = bool;

    fn len(&self) -> usize {
        Array::len(self)
    }

    unsafe fn value_unchecked(&self, idx: usize) -> Self::Item {
        BooleanArray::value_unchecked(self, idx)
    }

    fn is_eq(l: Self::Item, r: Self::Item) -> bool {
        l == r
    }

    fn is_lt(l: Self::Item, r: Self::Item) -> bool {
        !l & r
    }
}

impl<T: ArrowNativeTypeOp> ArrayOrd for &[T] {
    type Item = T;

    fn len(&self) -> usize {
        (*self).len()
    }

    unsafe fn value_unchecked(&self, idx: usize) -> Self::Item {
        *self.get_unchecked(idx)
    }

    fn is_eq(l: Self::Item, r: Self::Item) -> bool {
        l.is_eq(r)
    }

    fn is_lt(l: Self::Item, r: Self::Item) -> bool {
        l.is_lt(r)
    }
}

impl<'a, T: ByteArrayType> ArrayOrd for &'a GenericByteArray<T> {
    type Item = &'a [u8];

    fn len(&self) -> usize {
        Array::len(self)
    }

    unsafe fn value_unchecked(&self, idx: usize) -> Self::Item {
        GenericByteArray::value_unchecked(self, idx).as_ref()
    }

    fn is_eq(l: Self::Item, r: Self::Item) -> bool {
        l == r
    }

    fn is_lt(l: Self::Item, r: Self::Item) -> bool {
        l < r
    }
}

impl<'a> ArrayOrd for &'a FixedSizeBinaryArray {
    type Item = &'a [u8];

    fn len(&self) -> usize {
        Array::len(self)
    }

    unsafe fn value_unchecked(&self, idx: usize) -> Self::Item {
        FixedSizeBinaryArray::value_unchecked(self, idx)
    }

    fn is_eq(l: Self::Item, r: Self::Item) -> bool {
        l == r
    }

    fn is_lt(l: Self::Item, r: Self::Item) -> bool {
        l < r
    }
}

#[cfg(test)]
mod tests {
    use std::sync::Arc;

    use arrow_array::{DictionaryArray, Int32Array, Scalar, StringArray};

    use super::*;

    #[test]
    fn test_null_dict() {
        let a = DictionaryArray::new(Int32Array::new_null(10), Arc::new(Int32Array::new_null(0)));
        let r = eq(&a, &a).unwrap();
        assert_eq!(r.null_count(), 10);

        let a = DictionaryArray::new(
            Int32Array::from(vec![1, 2, 3, 4, 5, 6]),
            Arc::new(Int32Array::new_null(10)),
        );
        let r = eq(&a, &a).unwrap();
        assert_eq!(r.null_count(), 6);

        let scalar =
            DictionaryArray::new(Int32Array::new_null(1), Arc::new(Int32Array::new_null(0)));
        let r = eq(&a, &Scalar::new(&scalar)).unwrap();
        assert_eq!(r.null_count(), 6);

        let scalar =
            DictionaryArray::new(Int32Array::new_null(1), Arc::new(Int32Array::new_null(0)));
        let r = eq(&Scalar::new(&scalar), &Scalar::new(&scalar)).unwrap();
        assert_eq!(r.null_count(), 1);

        let a = DictionaryArray::new(
            Int32Array::from(vec![0, 1, 2]),
            Arc::new(Int32Array::from(vec![3, 2, 1])),
        );
        let r = eq(&a, &Scalar::new(&scalar)).unwrap();
        assert_eq!(r.null_count(), 3);
    }

    #[test]
    fn is_distinct_from_non_nulls() {
        let left_int_array = Int32Array::from(vec![0, 1, 2, 3, 4]);
        let right_int_array = Int32Array::from(vec![4, 3, 2, 1, 0]);

        assert_eq!(
            BooleanArray::from(vec![true, true, false, true, true,]),
            distinct(&left_int_array, &right_int_array).unwrap()
        );
        assert_eq!(
            BooleanArray::from(vec![false, false, true, false, false,]),
            not_distinct(&left_int_array, &right_int_array).unwrap()
        );
    }

    #[test]
    fn is_distinct_from_nulls() {
        // [0, 0, NULL, 0, 0, 0]
        let left_int_array = Int32Array::new(
            vec![0, 0, 1, 3, 0, 0].into(),
            Some(NullBuffer::from(vec![true, true, false, true, true, true])),
        );
        // [0, NULL, NULL, NULL, 0, NULL]
        let right_int_array = Int32Array::new(
            vec![0; 6].into(),
            Some(NullBuffer::from(vec![
                true, false, false, false, true, false,
            ])),
        );

        assert_eq!(
            BooleanArray::from(vec![false, true, false, true, false, true,]),
            distinct(&left_int_array, &right_int_array).unwrap()
        );

        assert_eq!(
            BooleanArray::from(vec![true, false, true, false, true, false,]),
            not_distinct(&left_int_array, &right_int_array).unwrap()
        );
    }

    #[test]
    fn test_distinct_scalar() {
        let a = Int32Array::new_scalar(12);
        let b = Int32Array::new_scalar(12);
        assert!(!distinct(&a, &b).unwrap().value(0));
        assert!(not_distinct(&a, &b).unwrap().value(0));

        let a = Int32Array::new_scalar(12);
        let b = Int32Array::new_null(1);
        assert!(distinct(&a, &b).unwrap().value(0));
        assert!(!not_distinct(&a, &b).unwrap().value(0));
        assert!(distinct(&b, &a).unwrap().value(0));
        assert!(!not_distinct(&b, &a).unwrap().value(0));

        let b = Scalar::new(b);
        assert!(distinct(&a, &b).unwrap().value(0));
        assert!(!not_distinct(&a, &b).unwrap().value(0));

        assert!(!distinct(&b, &b).unwrap().value(0));
        assert!(not_distinct(&b, &b).unwrap().value(0));

        let a = Int32Array::new(
            vec![0, 1, 2, 3].into(),
            Some(vec![false, false, true, true].into()),
        );
        let expected = BooleanArray::from(vec![false, false, true, true]);
        assert_eq!(distinct(&a, &b).unwrap(), expected);
        assert_eq!(distinct(&b, &a).unwrap(), expected);

        let expected = BooleanArray::from(vec![true, true, false, false]);
        assert_eq!(not_distinct(&a, &b).unwrap(), expected);
        assert_eq!(not_distinct(&b, &a).unwrap(), expected);

        let b = Int32Array::new_scalar(1);
        let expected = BooleanArray::from(vec![true; 4]);
        assert_eq!(distinct(&a, &b).unwrap(), expected);
        assert_eq!(distinct(&b, &a).unwrap(), expected);
        let expected = BooleanArray::from(vec![false; 4]);
        assert_eq!(not_distinct(&a, &b).unwrap(), expected);
        assert_eq!(not_distinct(&b, &a).unwrap(), expected);

        let b = Int32Array::new_scalar(3);
        let expected = BooleanArray::from(vec![true, true, true, false]);
        assert_eq!(distinct(&a, &b).unwrap(), expected);
        assert_eq!(distinct(&b, &a).unwrap(), expected);
        let expected = BooleanArray::from(vec![false, false, false, true]);
        assert_eq!(not_distinct(&a, &b).unwrap(), expected);
        assert_eq!(not_distinct(&b, &a).unwrap(), expected);
    }

    #[test]
    fn test_scalar_negation() {
        let a = Int32Array::new_scalar(54);
        let b = Int32Array::new_scalar(54);
        let r = eq(&a, &b).unwrap();
        assert!(r.value(0));

        let r = neq(&a, &b).unwrap();
        assert!(!r.value(0))
    }

    #[test]
    fn test_scalar_empty() {
        let a = Int32Array::new_null(0);
        let b = Int32Array::new_scalar(23);
        let r = eq(&a, &b).unwrap();
        assert_eq!(r.len(), 0);
        let r = eq(&b, &a).unwrap();
        assert_eq!(r.len(), 0);
    }

    #[test]
    fn test_dictionary_nulls() {
        let values = StringArray::from(vec![Some("us-west"), Some("us-east")]);
        let nulls = NullBuffer::from(vec![false, true, true]);

        let key_values = vec![100i32, 1i32, 0i32].into();
        let keys = Int32Array::new(key_values, Some(nulls));
        let col = DictionaryArray::try_new(keys, Arc::new(values)).unwrap();

        neq(&col.slice(0, col.len() - 1), &col.slice(1, col.len() - 1)).unwrap();
    }
}