foyer_common/utils/
range.rs

1// Copyright 2025 foyer Project Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use std::ops::{Add, Bound, Range, RangeBounds, Sub};
16
17mod private {
18
19    pub trait ZeroOne {
20        fn zero() -> Self;
21        fn one() -> Self;
22    }
23
24    macro_rules! impl_one {
25        ($($t:ty),*) => {
26            $(
27                impl ZeroOne for $t {
28                    fn zero() -> Self {
29                        0 as $t
30                    }
31
32                    fn one() -> Self {
33                        1 as $t
34                    }
35                }
36            )*
37        };
38    }
39
40    macro_rules! for_all_num_type {
41        ($macro:ident) => {
42            $macro! { u8, u16, u32, u64, usize, i8, i16, i32, i64, isize, f32, f64 }
43        };
44    }
45
46    for_all_num_type! { impl_one }
47}
48
49use private::ZeroOne;
50
51/// The range extensions.
52pub trait RangeBoundsExt<
53    T: PartialOrd<T> + Add<Output = T> + Sub<Output = T> + Clone + Copy + Send + Sync + 'static + ZeroOne,
54>: RangeBounds<T>
55{
56    /// Get the start bound of the range.
57    fn start(&self) -> Option<T> {
58        match self.start_bound() {
59            Bound::Included(v) => Some(*v),
60            Bound::Excluded(v) => Some(*v + ZeroOne::one()),
61            Bound::Unbounded => None,
62        }
63    }
64
65    /// Get the end bound of the range.
66    fn end(&self) -> Option<T> {
67        match self.end_bound() {
68            Bound::Included(v) => Some(*v + ZeroOne::one()),
69            Bound::Excluded(v) => Some(*v),
70            Bound::Unbounded => None,
71        }
72    }
73
74    /// Get the start bound with a default value of the range.
75    fn start_with_bound(&self, bound: T) -> T {
76        self.start().unwrap_or(bound)
77    }
78
79    /// Get the end bound with a default value of the range.
80    fn end_with_bound(&self, bound: T) -> T {
81        self.end().unwrap_or(bound)
82    }
83
84    /// Get the new range with the given range bounds.
85    fn bounds(&self, range: Range<T>) -> Range<T> {
86        let start = self.start_with_bound(range.start);
87        let end = self.end_with_bound(range.end);
88        start..end
89    }
90
91    /// Get the range size.
92    fn size(&self) -> Option<T> {
93        let start = self.start()?;
94        let end = self.end()?;
95        Some(end - start)
96    }
97
98    /// Check if the range is empty.
99    fn is_empty(&self) -> bool {
100        match self.size() {
101            Some(len) => len == ZeroOne::zero(),
102            None => false,
103        }
104    }
105
106    /// Check is the range is a full range.
107    fn is_full(&self) -> bool {
108        self.start_bound() == Bound::Unbounded && self.end_bound() == Bound::Unbounded
109    }
110
111    /// Map the range with the given method.
112    fn map<F, R>(&self, f: F) -> (Bound<R>, Bound<R>)
113    where
114        F: Fn(&T) -> R,
115    {
116        (self.start_bound().map(&f), self.end_bound().map(&f))
117    }
118}
119
120impl<
121        T: PartialOrd<T> + Add<Output = T> + Sub<Output = T> + Clone + Copy + Send + Sync + 'static + ZeroOne,
122        RB: RangeBounds<T>,
123    > RangeBoundsExt<T> for RB
124{
125}
foyer_common/utils/range.rs

foyer_common/utils/
range.rs
