myna_utils/
lib.rs

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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
use std::{fmt::Display, str::FromStr};

use sha2::Sha256;
use hmac::{Hmac, Mac};

#[derive(Debug, PartialEq, Eq)]
pub enum MynaError {
    ParseError(String),
    InvalidInput(String),
}

impl Display for MynaError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            MynaError::ParseError(s) => write!(f, "Parse error: {}", s),
            MynaError::InvalidInput(s) => write!(f, "Invalid input: {}", s),
        }
    }
}

impl std::error::Error for MynaError {}

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct Myna {
    digits: [u8; 11],
}

const Q_N: [u8; 11] = [6, 5, 4, 3, 2, 7, 6, 5, 4, 3, 2];

impl Myna {
    pub const ZERO: Myna = Myna { digits: [0; 11] };

    fn check_digit(&self) -> u8 {
        let mut sum = 0u16;
        for i in 0..11 {
            sum += self.digits[i] as u16 * Q_N[i] as u16;
        }
        let remainder = (sum % 11u16) as u8;
        if remainder == 0 || remainder == 1 {
            0
        } else {
            11 - remainder
        }
    }

    pub fn parse(input: &str) -> Result<Myna, MynaError> {
        let input = input.trim().as_bytes();
        if input.len() != 12 {
            return Err(MynaError::InvalidInput("Input must be 12 characters long".to_string()));
        }

        let mut bytes = [0; 12];
        for i in 0..12 {
            bytes[i] = match input[i] {
                b'0'..=b'9' => input[i] - b'0',
                _ => return Err(MynaError::ParseError("Invalid character".to_string())),
            };
        }

        let myna = Myna {
            digits: [bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5], bytes[6], bytes[7], bytes[8], bytes[9], bytes[10]],
        };

        if myna.check_digit() != bytes[11] {
            return Err(MynaError::ParseError("Invalid check digit".to_string()));
        }

        Ok(myna)
    }

    pub fn increment(&mut self) {
        let mut i = 10;
        loop {
            if self.digits[i] == 9 {
                self.digits[i] = 0;
                if i == 0 {
                    break;
                }
                i -= 1;
            } else {
                self.digits[i] += 1;
                break;
            }
        }
    }
}

impl FromStr for Myna {
    type Err = MynaError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Myna::parse(s)
    }
}

impl Display for Myna {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let zero = b'0';
        for i in 0..11 {
            write!(f, "{}", (self.digits[i] + zero) as char)?;
        }
        write!(f, "{}", self.check_digit())?;
        Ok(())
    }
}

impl Default for Myna {
    fn default() -> Self {
        Myna {
            digits: [0; 11],
        }
    }
}

pub struct MynaIter {
    myna: Myna,
}

impl MynaIter {
    pub fn new() -> MynaIter {
        MynaIter { myna: Myna::default() }
    }
}

impl Iterator for MynaIter {
    type Item = Myna;

    fn next(&mut self) -> Option<Self::Item> {
        let myna = self.myna;
        self.myna.increment();
        if self.myna == Myna::ZERO {
            return None;
        }
        Some(myna)
    }
}

type HmacSha256 = Hmac<Sha256>;

pub struct MynaDb {
    secret: Vec<u8>,
}

impl MynaDb {
    pub fn new(secret: &str) -> MynaDb {
        MynaDb {
            secret: secret.as_bytes().to_vec(),
        }
    }

    fn hash(&self, myna: &Myna) -> Vec<u8> {
        let mut mac = HmacSha256::new_from_slice(&self.secret).unwrap();
        mac.update(&myna.to_string().as_bytes());
        mac.finalize().into_bytes().to_vec()
    }

    fn uuid(&self, myna: &Myna) -> String {
        let hash = self.hash(myna);
        let mut uuid = [0u8; 16];
        uuid.copy_from_slice(&hash[..16]);

        // Set the version to 4 (random)
        uuid[6] = (uuid[6] & 0x0F) | 0x40;
        // Set the variant to DCE 1.1
        uuid[8] = (uuid[8] & 0x3F) | 0x80;

        let uuid = uuid.iter().map(|b| format!("{:02x}", b)).collect::<Vec<_>>().join("");
        format!(
            "{}-{}-{}-{}-{}",
            &uuid[0..8],
            &uuid[8..12],
            &uuid[12..16],
            &uuid[16..20],
            &uuid[20..32]
        )
    }

    pub fn get_line(&self, myna: &Myna) -> String {
        format!("{} {}\n", myna, self.uuid(myna))
    }
}