-
Notifications
You must be signed in to change notification settings - Fork 591
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
extract
range_except and range_diff out of buffer.rs
Signed-off-by: Richard Chien <[email protected]>
- Loading branch information
Showing
3 changed files
with
162 additions
and
139 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,158 @@ | ||
| // Copyright 2024 RisingWave Labs | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
|
||
| use std::ops::Range; | ||
|
|
||
| use smallvec::{smallvec, SmallVec}; | ||
|
|
||
| /// Calculate range (A - B), the result might be the union of two ranges when B is totally included | ||
| /// in the A. | ||
| pub(super) fn range_except(a: Range<usize>, b: Range<usize>) -> (Range<usize>, Range<usize>) { | ||
| #[allow(clippy::if_same_then_else)] // for better readability | ||
| if a.is_empty() { | ||
| (0..0, 0..0) | ||
| } else if b.is_empty() { | ||
| (a, 0..0) | ||
| } else if a.end <= b.start || b.end <= a.start { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| // or | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (a, 0..0) | ||
| } else if b.start <= a.start && a.end <= b.end { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (0..0, 0..0) | ||
| } else if a.start < b.start && b.end < a.end { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (a.start..b.start, b.end..a.end) | ||
| } else if a.end <= b.end { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (a.start..b.start, 0..0) | ||
| } else if b.start <= a.start { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (b.end..a.end, 0..0) | ||
| } else { | ||
| unreachable!() | ||
| } | ||
| } | ||
|
|
||
| /// Calculate the difference of two ranges A and B, return (removed ranges, added ranges). | ||
| /// Note this is quite different from [`range_except`]. | ||
| #[allow(clippy::type_complexity)] // looks complex but it's not | ||
| pub(super) fn range_diff( | ||
| a: Range<usize>, | ||
| b: Range<usize>, | ||
| ) -> (SmallVec<[Range<usize>; 2]>, SmallVec<[Range<usize>; 2]>) { | ||
| if a.start == b.start { | ||
| match a.end.cmp(&b.end) { | ||
| std::cmp::Ordering::Equal => { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![], smallvec![]) | ||
| } | ||
| std::cmp::Ordering::Less => { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![], smallvec![a.end..b.end]) | ||
| } | ||
| std::cmp::Ordering::Greater => { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![b.end..a.end], smallvec![]) | ||
| } | ||
| } | ||
| } else if a.end == b.end { | ||
| debug_assert!(a.start != b.start); | ||
| if a.start < b.start { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![a.start..b.start], smallvec![]) | ||
| } else { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![], smallvec![b.start..a.start]) | ||
| } | ||
| } else { | ||
| debug_assert!(a.start != b.start && a.end != b.end); | ||
| if a.end <= b.start || b.end <= a.start { | ||
| // a: [ ) | ||
| // b: [ [ ) | ||
| // or | ||
| // a: [ ) | ||
| // b: [ ) ) | ||
| (smallvec![a], smallvec![b]) | ||
| } else if b.start < a.start && a.end < b.end { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![], smallvec![b.start..a.start, a.end..b.end]) | ||
| } else if a.start < b.start && b.end < a.end { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![a.start..b.start, b.end..a.end], smallvec![]) | ||
| } else if a.end < b.end { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![a.start..b.start], smallvec![a.end..b.end]) | ||
| } else { | ||
| // a: [ ) | ||
| // b: [ ) | ||
| (smallvec![b.end..a.end], smallvec![b.start..a.start]) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
| mod tests { | ||
| use std::collections::HashSet; | ||
|
|
||
| use super::*; | ||
|
|
||
| #[test] | ||
| fn test_range_diff() { | ||
| fn test( | ||
| a: Range<usize>, | ||
| b: Range<usize>, | ||
| expected_removed: impl IntoIterator<Item = usize>, | ||
| expected_added: impl IntoIterator<Item = usize>, | ||
| ) { | ||
| let (removed, added) = range_diff(a, b); | ||
| let removed_set = removed.into_iter().flatten().collect::<HashSet<_>>(); | ||
| let added_set = added.into_iter().flatten().collect::<HashSet<_>>(); | ||
| let expected_removed_set = expected_removed.into_iter().collect::<HashSet<_>>(); | ||
| let expected_added_set = expected_added.into_iter().collect::<HashSet<_>>(); | ||
| assert_eq!(removed_set, expected_removed_set); | ||
| assert_eq!(added_set, expected_added_set); | ||
| } | ||
|
|
||
| test(0..0, 0..0, [], []); | ||
| test(0..1, 0..1, [], []); | ||
| test(0..1, 0..2, [], [1]); | ||
| test(0..2, 0..1, [1], []); | ||
| test(0..2, 1..2, [0], []); | ||
| test(1..2, 0..2, [], [0]); | ||
| test(0..1, 1..2, [0], [1]); | ||
| test(0..1, 2..3, [0], [2]); | ||
| test(1..2, 0..1, [1], [0]); | ||
| test(2..3, 0..1, [2], [0]); | ||
| test(0..3, 1..2, [0, 2], []); | ||
| test(1..2, 0..3, [], [0, 2]); | ||
| test(0..3, 2..4, [0, 1], [3]); | ||
| test(2..4, 0..3, [3], [0, 1]); | ||
| } | ||
| } |