1//! The module contains [`Peaker`] trait and its implementations to be used in [`Height`] and [`Width`].
2//!
3//! [`Width`]: crate::settings::width::Width
4//! [`Height`]: crate::settings::height::Height
5
6/// A strategy of width function.
7/// It determines the order how the function is applied.
8pub trait Peaker {
9 /// Creates a new instance.
10 fn create() -> Self;
11 /// This function returns a column index which will be changed.
12 /// Or `None` if no changes are necessary.
13 fn peak(&mut self, min_widths: &[usize], widths: &[usize]) -> Option<usize>;
14}
15
16/// A Peaker which goes over column 1 by 1.
17#[derive(Debug, Default, Clone)]
18pub struct PriorityNone {
19 i: usize,
20}
21
22impl Peaker for PriorityNone {
23 fn create() -> Self {
24 Self { i: 0 }
25 }
26
27 fn peak(&mut self, _: &[usize], widths: &[usize]) -> Option<usize> {
28 let mut i = self.i;
29 let mut count_empty = 0;
30 while widths[i] == 0 {
31 i += 1;
32 if i >= widths.len() {
33 i = 0;
34 }
35
36 count_empty += 1;
37 if count_empty == widths.len() {
38 return None;
39 }
40 }
41
42 let col = i;
43
44 i += 1;
45 if i >= widths.len() {
46 i = 0;
47 }
48
49 self.i = i;
50
51 Some(col)
52 }
53}
54
55/// A Peaker which goes over the biggest column first.
56#[derive(Debug, Default, Clone)]
57pub struct PriorityMax;
58
59impl Peaker for PriorityMax {
60 fn create() -> Self {
61 Self
62 }
63
64 fn peak(&mut self, _: &[usize], widths: &[usize]) -> Option<usize> {
65 let col: usize = (0..widths.len()).max_by_key(|&i: usize| widths[i]).unwrap();
66 if widths[col] == 0 {
67 None
68 } else {
69 Some(col)
70 }
71 }
72}
73
74/// A Peaker which goes over the smallest column first.
75#[derive(Debug, Default, Clone)]
76pub struct PriorityMin;
77
78impl Peaker for PriorityMin {
79 fn create() -> Self {
80 Self
81 }
82
83 fn peak(&mut self, min_widths: &[usize], widths: &[usize]) -> Option<usize> {
84 let col: usize = (0..widths.len())
85 .filter(|&i: usize| min_widths.is_empty() || widths[i] > min_widths[i])
86 .min_by_key(|&i: usize| widths[i])
87 .unwrap();
88 if widths[col] == 0 {
89 None
90 } else {
91 Some(col)
92 }
93 }
94}
95