moxcms/matan/
degeneration.rs

1/*
2 * // Copyright (c) Radzivon Bartoshyk 6/2025. 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#[derive(Copy, Clone, Default, Debug)]
31struct DegenerationAmount {
32    leading: usize,
33    trailing: usize,
34}
35
36/// Counts amount of duplicates on each side of curve
37fn count_leading_trailing_duplicated<T: PartialOrd>(lut: &[T]) -> DegenerationAmount {
38    if lut.is_empty() {
39        return DegenerationAmount::default();
40    }
41    let first = lut.first().unwrap();
42    let last = lut.last().unwrap();
43    let leading = lut.iter().take_while(|&v| v.eq(first)).count();
44    let trailing = lut.iter().rev().take_while(|&v| v.eq(last)).count();
45    DegenerationAmount { leading, trailing }
46}
47
48/// Finds out if curve is degenerated on the sides.
49pub(crate) fn is_curve_degenerated<T: PartialOrd>(v: &[T]) -> bool {
50    if v.is_empty() || v.len() < 2 {
51        return false;
52    }
53    let degeneration_amount = count_leading_trailing_duplicated(v);
54    if degeneration_amount.trailing <= 1 && degeneration_amount.leading <= 1 {
55        return false;
56    }
57    let leading_percentage = degeneration_amount.leading;
58    let trailing_percentage = degeneration_amount.trailing;
59    ((leading_percentage / 20) > 0) || ((trailing_percentage / 20) > 0)
60}
moxcms/matan/degeneration.rs

moxcms/matan/
degeneration.rs
