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
158
159

pub const FIRST_BIT: u32 = 0x80000000;

#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
pub enum PathValue {
    Normal(u32),
    Hardened(u32)
}

impl PathValue {
    pub fn is_ok(value: u32) -> bool {
        value < FIRST_BIT
    }

    pub fn try_normal(value: u32) -> Result<PathValue, ()> {
        if !PathValue::is_ok(value) {
            Err(())
        } else {
            Ok(PathValue::Normal(value))
        }
    }

    pub fn normal(value: u32) -> PathValue {
        if let Ok(result) = PathValue::try_normal(value) {
            result
        } else {
            panic!("Raw hardened value passed")
        }
    }

    pub fn try_hardened(value: u32) -> Result<PathValue, ()> {
        if !PathValue::is_ok(value) {
            Err(())
        } else {
            Ok(PathValue::Hardened(value))
        }
    }

    pub fn hardened(value: u32) -> PathValue {
        if let Ok(result) = PathValue::try_hardened(value) {
            result
        } else {
            panic!("Raw hardened value passed")
        }
    }

    pub fn from_raw(value: u32) -> PathValue {
        if value >= FIRST_BIT {
            PathValue::Hardened(value - FIRST_BIT)
        } else {
            PathValue::Normal(value)
        }
    }

    pub fn as_number(&self) -> u32 {
        match &self {
            PathValue::Normal(n) => *n,
            PathValue::Hardened(n) => *n
        }
    }

    pub fn to_raw(&self) -> u32 {
        match &self {
            PathValue::Normal(n) => *n,
            PathValue::Hardened(n) => *n + FIRST_BIT
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn ok_for_small_values() {
        let values = vec![
            0u32, 1, 2, 3,
            100, 1000, 10000,
            0x80000000 - 1
        ];
        for value in values {
            assert!(PathValue::is_ok(value), "value: {}", value);
        }
    }

    #[test]
    fn not_ok_for_large_values() {
        let values = vec![
            0x80000000, 0x80000001,
            0xffffffff
        ];
        for value in values {
            assert!(!PathValue::is_ok(value), "value: {}", value);
        }
    }

    #[test]
    fn create_normal() {
        assert_eq!(PathValue::Normal(0), PathValue::normal(0));
        assert_eq!(PathValue::Normal(1), PathValue::normal(1));
        assert_eq!(PathValue::Normal(101), PathValue::normal(101));
    }

    #[test]
    fn create_hardened() {
        assert_eq!(PathValue::Hardened(0), PathValue::hardened(0));
        assert_eq!(PathValue::Hardened(1), PathValue::hardened(1));
        assert_eq!(PathValue::Hardened(101), PathValue::hardened(101));
    }

    #[test]
    #[should_panic]
    fn panic_on_invalid_normal() {
        PathValue::normal(0x80000001);
    }

    #[test]
    #[should_panic]
    fn panic_on_invalid_hardened() {
        PathValue::hardened(0x80000001);
    }

    #[test]
    fn create_from_raw_normal() {
        assert_eq!(PathValue::Normal(0), PathValue::from_raw(0));
        assert_eq!(PathValue::Normal(100), PathValue::from_raw(100));
        assert_eq!(PathValue::Normal(0xffffff), PathValue::from_raw(0xffffff));
    }

    #[test]
    fn create_from_raw_hardened() {
        assert_eq!(PathValue::hardened(0), PathValue::from_raw(0x80000000));
        assert_eq!(PathValue::hardened(1), PathValue::from_raw(0x80000001));
        assert_eq!(PathValue::hardened(44), PathValue::from_raw(0x8000002c));
    }

    #[test]
    fn to_raw_normal() {
        assert_eq!(0, PathValue::Normal(0).to_raw());
        assert_eq!(123, PathValue::Normal(123).to_raw());
    }

    #[test]
    fn to_raw_hardened() {
        assert_eq!(0x80000000, PathValue::Hardened(0).to_raw());
        assert_eq!(0x8000002c, PathValue::Hardened(44).to_raw());
    }

    #[test]
    fn as_number_normal() {
        assert_eq!(0, PathValue::Normal(0).as_number());
        assert_eq!(123, PathValue::Normal(123).as_number());
    }

    #[test]
    fn as_number_hardened() {
        assert_eq!(0, PathValue::Hardened(0).as_number());
        assert_eq!(123, PathValue::Hardened(123).as_number());
    }
}