arrow_data/equal/
variable_size.rs

1// Licensed to the Apache Software Foundation (ASF) under one
2// or more contributor license agreements.  See the NOTICE file
3// distributed with this work for additional information
4// regarding copyright ownership.  The ASF licenses this file
5// to you under the Apache License, Version 2.0 (the
6// "License"); you may not use this file except in compliance
7// with the License.  You may obtain a copy of the License at
8//
9//   http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing,
12// software distributed under the License is distributed on an
13// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14// KIND, either express or implied.  See the License for the
15// specific language governing permissions and limitations
16// under the License.
17
18use super::utils::equal_len;
19use crate::data::{ArrayData, contains_nulls};
20use crate::equal::list::lengths_equal;
21use arrow_buffer::ArrowNativeType;
22use num_integer::Integer;
23
24fn offset_value_equal<T: ArrowNativeType + Integer>(
25    lhs_values: &[u8],
26    rhs_values: &[u8],
27    lhs_offsets: &[T],
28    rhs_offsets: &[T],
29    lhs_pos: usize,
30    rhs_pos: usize,
31    len: usize,
32) -> bool {
33    let lhs_start = lhs_offsets[lhs_pos].as_usize();
34    let rhs_start = rhs_offsets[rhs_pos].as_usize();
35    let lhs_len = (lhs_offsets[lhs_pos + len] - lhs_offsets[lhs_pos])
36        .to_usize()
37        .unwrap();
38    let rhs_len = (rhs_offsets[rhs_pos + len] - rhs_offsets[rhs_pos])
39        .to_usize()
40        .unwrap();
41
42    if lhs_len == 0 && rhs_len == 0 {
43        return true;
44    }
45
46    lhs_len == rhs_len && equal_len(lhs_values, rhs_values, lhs_start, rhs_start, lhs_len)
47}
48
49pub(super) fn variable_sized_equal<T: ArrowNativeType + Integer>(
50    lhs: &ArrayData,
51    rhs: &ArrayData,
52    lhs_start: usize,
53    rhs_start: usize,
54    len: usize,
55) -> bool {
56    let lhs_offsets = lhs.buffer::<T>(0);
57    let rhs_offsets = rhs.buffer::<T>(0);
58
59    // the offsets of the `ArrayData` are ignored as they are only applied to the offset buffer.
60    let lhs_values = lhs.buffers()[1].as_slice();
61    let rhs_values = rhs.buffers()[1].as_slice();
62
63    // Only checking one null mask here because by the time the control flow reaches
64    // this point, the equality of the two masks would have already been verified.
65    if !contains_nulls(lhs.nulls(), lhs_start, len) {
66        let lhs_offsets_slice = &lhs_offsets[lhs_start..lhs_start + len + 1];
67        let rhs_offsets_slice = &rhs_offsets[rhs_start..rhs_start + len + 1];
68        lengths_equal(lhs_offsets_slice, rhs_offsets_slice)
69            && offset_value_equal(
70                lhs_values,
71                rhs_values,
72                lhs_offsets,
73                rhs_offsets,
74                lhs_start,
75                rhs_start,
76                len,
77            )
78    } else {
79        (0..len).all(|i| {
80            let lhs_pos = lhs_start + i;
81            let rhs_pos = rhs_start + i;
82
83            // the null bits can still be `None`, indicating that the value is valid.
84            let lhs_is_null = lhs.nulls().map(|v| v.is_null(lhs_pos)).unwrap_or_default();
85            let rhs_is_null = rhs.nulls().map(|v| v.is_null(rhs_pos)).unwrap_or_default();
86
87            lhs_is_null
88                || (lhs_is_null == rhs_is_null)
89                    && offset_value_equal(
90                        lhs_values,
91                        rhs_values,
92                        lhs_offsets,
93                        rhs_offsets,
94                        lhs_pos,
95                        rhs_pos,
96                        1,
97                    )
98        })
99    }
100}
101
102#[cfg(test)]
103mod tests {
104    use crate::ArrayData;
105    use crate::equal::variable_size::variable_sized_equal;
106    use arrow_buffer::Buffer;
107    use arrow_schema::DataType;
108
109    #[test]
110    fn test_variable_sized_equal_diff_offsets() {
111        let a = ArrayData::builder(DataType::Utf8)
112            .buffers(vec![
113                Buffer::from_vec(vec![0_i32, 3, 6]),
114                Buffer::from_slice_ref(b"foobar"),
115            ])
116            .null_bit_buffer(Some(Buffer::from_slice_ref([0b01_u8])))
117            .len(2)
118            .build()
119            .unwrap();
120        let b = ArrayData::builder(DataType::Utf8)
121            .buffers(vec![
122                Buffer::from_vec(vec![0_i32, 2, 6]),
123                Buffer::from_slice_ref(b"foobar"),
124            ])
125            .null_bit_buffer(Some(Buffer::from_slice_ref([0b01_u8])))
126            .len(2)
127            .build()
128            .unwrap();
129
130        assert!(!variable_sized_equal::<i32>(&a, &b, 0, 0, 2));
131    }
132}
arrow_data/equal/variable_size.rs

arrow_data/equal/
variable_size.rs
