/rust/registry/src/index.crates.io-1949cf8c6b5b557f/pxfm-0.1.25/src/rounding/rint.rs
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1 | | /* |
2 | | * // Copyright (c) Radzivon Bartoshyk 9/2025. All rights reserved. |
3 | | * // |
4 | | * // Redistribution and use in source and binary forms, with or without modification, |
5 | | * // are permitted provided that the following conditions are met: |
6 | | * // |
7 | | * // 1. Redistributions of source code must retain the above copyright notice, this |
8 | | * // list of conditions and the following disclaimer. |
9 | | * // |
10 | | * // 2. Redistributions in binary form must reproduce the above copyright notice, |
11 | | * // this list of conditions and the following disclaimer in the documentation |
12 | | * // and/or other materials provided with the distribution. |
13 | | * // |
14 | | * // 3. Neither the name of the copyright holder nor the names of its |
15 | | * // contributors may be used to endorse or promote products derived from |
16 | | * // this software without specific prior written permission. |
17 | | * // |
18 | | * // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
19 | | * // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
20 | | * // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
21 | | * // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE |
22 | | * // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
23 | | * // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
24 | | * // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
25 | | * // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
26 | | * // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
27 | | * // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
28 | | */ |
29 | | |
30 | | #[inline] |
31 | 0 | pub const fn rint(x: f64) -> f64 { |
32 | | /* Use generic implementation. */ |
33 | | static TWO52: [f64; 2] = [ |
34 | | 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ |
35 | | -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ |
36 | | ]; |
37 | 0 | let mut i0: i64 = x.to_bits() as i64; |
38 | 0 | let sx = (i0 >> 63) & 1; |
39 | 0 | let j0: i32 = (((i0 >> 52) & 0x7ff) - 0x3ff) as i32; |
40 | 0 | if j0 < 52 { |
41 | 0 | if j0 < 0 { |
42 | 0 | let w = TWO52[sx as usize] + x; |
43 | 0 | let t = w - TWO52[sx as usize]; |
44 | 0 | i0 = t.to_bits() as i64; |
45 | 0 | let u = (i0 & (0x7fffffffffffffffu64 as i64)) | (sx << 63); |
46 | 0 | return f64::from_bits(u as u64); |
47 | 0 | } |
48 | | } else { |
49 | 0 | return if j0 == 0x400 { |
50 | 0 | x + x /* inf or NaN */ |
51 | | } else { |
52 | 0 | x /* x is integral */ |
53 | | }; |
54 | | } |
55 | 0 | let w = TWO52[sx as usize] + x; |
56 | 0 | w - TWO52[sx as usize] |
57 | 0 | } |
58 | | |
59 | | #[cfg(test)] |
60 | | mod tests { |
61 | | use super::*; |
62 | | #[test] |
63 | | fn test_rintf() { |
64 | | assert_eq!(rint(0f64), 0.0f64.round()); |
65 | | assert_eq!(rint(1f64), 1.0f64.round()); |
66 | | assert_eq!(rint(1.2f64), 1.2f64.round()); |
67 | | assert_eq!(rint(-1.2f64), (-1.2f64).round()); |
68 | | assert_eq!(rint(-1.6f64), (-1.6f64).round()); |
69 | | assert_eq!(rint(-1.5f64), (-1.5f64).round()); |
70 | | assert_eq!(rint(1.6f64), 1.6f64.round()); |
71 | | assert_eq!(rint(1.5f64), 1.5f64.round()); |
72 | | assert_eq!(rint(2.5f64), 2.0f64); |
73 | | assert_eq!(rint(3.5f64), 4.0f64); |
74 | | assert_eq!(rint(-2.5f64), -2.0f64); |
75 | | assert_eq!(rint(-3.5f64), -4.0f64); |
76 | | assert_eq!(rint(f64::INFINITY), f64::INFINITY); |
77 | | assert_eq!(rint(f64::NEG_INFINITY), f64::NEG_INFINITY); |
78 | | assert!(rint(f64::NAN).is_nan()); |
79 | | } |
80 | | } |