1 | //! Fixed size parameters list with optional subparameters. |
2 | |
3 | use core::fmt::{self, Debug, Formatter}; |
4 | |
5 | pub(crate) const MAX_PARAMS: usize = 32; |
6 | |
7 | #[derive (Default, Clone, PartialEq, Eq)] |
8 | pub struct Params { |
9 | /// Number of subparameters for each parameter. |
10 | /// |
11 | /// For each entry in the `params` slice, this stores the length of the param as number of |
12 | /// subparams at the same index as the param in the `params` slice. |
13 | /// |
14 | /// At the subparam positions the length will always be `0`. |
15 | subparams: [u8; MAX_PARAMS], |
16 | |
17 | /// All parameters and subparameters. |
18 | params: [u16; MAX_PARAMS], |
19 | |
20 | /// Number of suparameters in the current parameter. |
21 | current_subparams: u8, |
22 | |
23 | /// Total number of parameters and subparameters. |
24 | len: usize, |
25 | } |
26 | |
27 | impl Params { |
28 | /// Returns the number of parameters. |
29 | #[inline ] |
30 | pub fn len(&self) -> usize { |
31 | self.len |
32 | } |
33 | |
34 | /// Returns `true` if there are no parameters present. |
35 | #[inline ] |
36 | pub fn is_empty(&self) -> bool { |
37 | self.len == 0 |
38 | } |
39 | |
40 | /// Returns an iterator over all parameters and subparameters. |
41 | #[inline ] |
42 | pub fn iter(&self) -> ParamsIter<'_> { |
43 | ParamsIter::new(self) |
44 | } |
45 | |
46 | /// Returns `true` if there is no more space for additional parameters. |
47 | #[inline ] |
48 | pub(crate) fn is_full(&self) -> bool { |
49 | self.len == MAX_PARAMS |
50 | } |
51 | |
52 | /// Clear all parameters. |
53 | #[inline ] |
54 | pub(crate) fn clear(&mut self) { |
55 | self.current_subparams = 0; |
56 | self.len = 0; |
57 | } |
58 | |
59 | /// Add an additional parameter. |
60 | #[inline ] |
61 | pub(crate) fn push(&mut self, item: u16) { |
62 | self.subparams[self.len - self.current_subparams as usize] = self.current_subparams + 1; |
63 | self.params[self.len] = item; |
64 | self.current_subparams = 0; |
65 | self.len += 1; |
66 | } |
67 | |
68 | /// Add an additional subparameter to the current parameter. |
69 | #[inline ] |
70 | pub(crate) fn extend(&mut self, item: u16) { |
71 | self.subparams[self.len - self.current_subparams as usize] = self.current_subparams + 1; |
72 | self.params[self.len] = item; |
73 | self.current_subparams += 1; |
74 | self.len += 1; |
75 | } |
76 | } |
77 | |
78 | impl<'a> IntoIterator for &'a Params { |
79 | type IntoIter = ParamsIter<'a>; |
80 | type Item = &'a [u16]; |
81 | |
82 | fn into_iter(self) -> Self::IntoIter { |
83 | self.iter() |
84 | } |
85 | } |
86 | |
87 | /// Immutable subparameter iterator. |
88 | pub struct ParamsIter<'a> { |
89 | params: &'a Params, |
90 | index: usize, |
91 | } |
92 | |
93 | impl<'a> ParamsIter<'a> { |
94 | fn new(params: &'a Params) -> Self { |
95 | Self { params, index: 0 } |
96 | } |
97 | } |
98 | |
99 | impl<'a> Iterator for ParamsIter<'a> { |
100 | type Item = &'a [u16]; |
101 | |
102 | fn next(&mut self) -> Option<Self::Item> { |
103 | if self.index >= self.params.len() { |
104 | return None; |
105 | } |
106 | |
107 | // Get all subparameters for the current parameter. |
108 | let num_subparams: u8 = self.params.subparams[self.index]; |
109 | let param: &[u16] = &self.params.params[self.index..self.index + num_subparams as usize]; |
110 | |
111 | // Jump to the next parameter. |
112 | self.index += num_subparams as usize; |
113 | |
114 | Some(param) |
115 | } |
116 | |
117 | fn size_hint(&self) -> (usize, Option<usize>) { |
118 | let remaining: usize = self.params.len() - self.index; |
119 | (remaining, Some(remaining)) |
120 | } |
121 | } |
122 | |
123 | impl Debug for Params { |
124 | fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result { |
125 | write!(f, "[" )?; |
126 | |
127 | for (i: usize, param: &[u16]) in self.iter().enumerate() { |
128 | if i != 0 { |
129 | write!(f, ";" )?; |
130 | } |
131 | |
132 | for (i: usize, subparam: &u16) in param.iter().enumerate() { |
133 | if i != 0 { |
134 | write!(f, ":" )?; |
135 | } |
136 | |
137 | subparam.fmt(f)?; |
138 | } |
139 | } |
140 | |
141 | write!(f, "]" ) |
142 | } |
143 | } |
144 | |