fyrox_core/
numeric_range.rs

1// Copyright (c) 2019-present Dmitry Stepanov and Fyrox Engine contributors.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy
4// of this software and associated documentation files (the "Software"), to deal
5// in the Software without restriction, including without limitation the rights
6// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7// copies of the Software, and to permit persons to whom the Software is
8// furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in all
11// copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
19// SOFTWARE.
20
21use crate::num_traits::Num;
22use rand::distributions::uniform::SampleUniform;
23use rand::Rng;
24use std::ops::Range;
25
26fn min<T>(a: T, b: T) -> T
27where
28    T: PartialOrd,
29{
30    if a > b {
31        b
32    } else {
33        a
34    }
35}
36
37fn max<T>(a: T, b: T) -> T
38where
39    T: PartialOrd,
40{
41    if a > b {
42        a
43    } else {
44        b
45    }
46}
47
48pub trait RangeExt<T>
49where
50    T: Num + PartialOrd + SampleUniform + Copy,
51{
52    fn random<R: Rng>(&self, rng: &mut R) -> T;
53
54    fn clamp_value(&self, value: &mut T) -> T;
55}
56
57impl<T: Num + PartialOrd + SampleUniform + Copy> RangeExt<T> for Range<T> {
58    #[inline]
59    fn random<R: Rng>(&self, rng: &mut R) -> T {
60        let start = min(self.start, self.end);
61        let end = max(self.start, self.end);
62        if start == end {
63            start
64        } else {
65            rng.gen_range(Range { start, end })
66        }
67    }
68
69    #[inline]
70    fn clamp_value(&self, value: &mut T) -> T {
71        let start = min(self.start, self.end);
72        let end = max(self.start, self.end);
73
74        if *value < start {
75            start
76        } else if *value > end {
77            end
78        } else {
79            *value
80        }
81    }
82}
83
84#[cfg(test)]
85mod test {
86    use rand::thread_rng;
87
88    use super::*;
89
90    #[test]
91    fn test_random() {
92        let mut rng = thread_rng();
93
94        let res = (1..10).random(&mut rng);
95        assert!((1..=10).contains(&res));
96
97        let res = Range { start: 10, end: 1 }.random(&mut rng);
98        assert!((1..=10).contains(&res));
99
100        let res = (1..1).random(&mut rng);
101        assert!(res == 1);
102    }
103
104    #[test]
105    fn test_clamp_value() {
106        let res = (1..10).clamp_value(&mut 5);
107        assert_eq!(res, 5);
108
109        let res = (1..10).clamp_value(&mut 0);
110        assert_eq!(res, 1);
111
112        let res = (1..10).clamp_value(&mut 11);
113        assert_eq!(res, 10);
114    }
115}
fyrox_core/numeric_range.rs

fyrox_core/
numeric_range.rs
