ordinal-map 0.1.10

Ordinal trait to map values to integers and efficient maps and sets for such types
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

use crate::Ordinal;

impl Ordinal for bool {
    const ORDINAL_SIZE: usize = 2;

    fn ordinal(&self) -> usize {
        *self as usize
    }

    fn from_ordinal(ordinal: usize) -> Option<Self> {
        match ordinal {
            0 => Some(false),
            1 => Some(true),
            _ => None,
        }
    }
}

impl Ordinal for u8 {
    const ORDINAL_SIZE: usize = u8::MAX as usize + 1;

    #[inline]
    fn ordinal(&self) -> usize {
        *self as usize
    }

    #[inline]
    fn from_ordinal(ordinal: usize) -> Option<Self> {
        u8::try_from(ordinal).ok()
    }
}

impl Ordinal for i8 {
    const ORDINAL_SIZE: usize = (i8::MAX as i16 - i8::MIN as i16 + 1) as usize;

    #[inline]
    fn ordinal(&self) -> usize {
        self.abs_diff(i8::MIN) as usize
    }

    #[inline]
    fn from_ordinal(ordinal: usize) -> Option<Self> {
        i8::MIN.checked_add_unsigned(u8::try_from(ordinal).ok()?)
    }
}

impl Ordinal for u16 {
    const ORDINAL_SIZE: usize = u16::MAX as usize + 1;

    #[inline]
    fn ordinal(&self) -> usize {
        *self as usize
    }

    #[inline]
    fn from_ordinal(ordinal: usize) -> Option<Self> {
        u16::try_from(ordinal).ok()
    }
}

impl Ordinal for i16 {
    const ORDINAL_SIZE: usize = (i16::MAX as isize - i16::MIN as isize + 1) as usize;

    #[inline]
    fn ordinal(&self) -> usize {
        self.abs_diff(i16::MIN) as usize
    }

    #[inline]
    fn from_ordinal(ordinal: usize) -> Option<Self> {
        i16::MIN.checked_add_unsigned(u16::try_from(ordinal).ok()?)
    }
}

/// Accessing this type is compile time error on 32-bit platforms.
impl Ordinal for u32 {
    const ORDINAL_SIZE: usize = u32::MAX as usize + 1;

    #[inline]
    fn ordinal(&self) -> usize {
        const { Self::ORDINAL_SIZE };
        *self as usize
    }

    #[inline]
    fn from_ordinal(ordinal: usize) -> Option<Self> {
        u32::try_from(ordinal).ok()
    }
}

impl Ordinal for i32 {
    const ORDINAL_SIZE: usize = u32::ORDINAL_SIZE;

    #[inline]
    fn ordinal(&self) -> usize {
        const { Self::ORDINAL_SIZE };
        self.abs_diff(i32::MIN) as usize
    }

    #[inline]
    fn from_ordinal(ordinal: usize) -> Option<Self> {
        const { Self::ORDINAL_SIZE };
        i32::MIN.checked_add_unsigned(u32::try_from(ordinal).ok()?)
    }
}

#[cfg(test)]
mod tests {
    use crate::tests::util::test_ordinal;
    use crate::Ordinal;

    #[test]
    fn test_bool() {
        test_ordinal::<bool>([false, true]);
    }

    #[test]
    fn test_u8() {
        test_ordinal::<u8>(0..=255);
    }

    #[test]
    fn test_i8() {
        test_ordinal::<i8>(i8::MIN..=i8::MAX);
    }

    #[test]
    fn test_u16() {
        test_ordinal::<u16>(0..=u16::MAX);
    }

    #[test]
    fn test_i16() {
        test_ordinal::<i16>(i16::MIN..=i16::MAX);
    }

    #[test]
    fn test_u32() {
        if cfg!(target_pointer_width = "64") {
            let mut iter = u32::all_values();
            assert_eq!(u32::MAX as usize + 1, iter.len());
            assert_eq!(Some(0), iter.next());
            assert_eq!(Some(1), iter.next());
            assert_eq!(Some(u32::MAX), iter.next_back());
        }
    }

    #[test]
    fn test_i32() {
        if cfg!(target_pointer_width = "64") {
            let mut iter = i32::all_values();
            assert_eq!(u32::MAX as usize + 1, iter.len());
            assert_eq!(Some(i32::MIN), iter.next());
            assert_eq!(Some(i32::MAX), iter.next_back());
        }
    }
}