/rust/registry/src/index.crates.io-1949cf8c6b5b557f/pxfm-0.1.25/src/rounding/trunc.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 trunc(x: f64) -> f64 { |
32 | 0 | let i0 = x.to_bits() as i64; |
33 | 0 | let sx = i0 & (0x8000000000000000u64 as i64); |
34 | 0 | let j0 = ((i0 >> 52) & 0x7ff) - 0x3ff; |
35 | 0 | if j0 < 52 { |
36 | 0 | return if j0 < 0 { |
37 | | /* The magnitude of the number is < 1 so the result is +-0. */ |
38 | 0 | f64::from_bits(sx as u64) |
39 | | } else { |
40 | 0 | f64::from_bits((sx | (i0 & (!(0x000fffffffffffffu64 >> j0) as i64))) as u64) |
41 | | }; |
42 | 0 | } else if j0 == 0x400 { |
43 | | /* x is inf or NaN. */ |
44 | 0 | return x + x; |
45 | 0 | } |
46 | | |
47 | 0 | x |
48 | 0 | } |
49 | | |
50 | | #[cfg(test)] |
51 | | mod tests { |
52 | | use super::*; |
53 | | |
54 | | #[test] |
55 | | fn test_trunc() { |
56 | | assert_eq!(trunc(-1.0), -1.0); |
57 | | assert_eq!(trunc(1.0), 1.0); |
58 | | assert_eq!(trunc(1.234211), 1.0); |
59 | | assert_eq!(trunc(-1.234211), -1.0); |
60 | | assert_eq!(trunc(f64::INFINITY), f64::INFINITY); |
61 | | assert_eq!(trunc(f64::NEG_INFINITY), f64::NEG_INFINITY); |
62 | | assert!(trunc(f64::NAN).is_nan()); |
63 | | } |
64 | | } |