gridish/
utils.rs

1use crate::{Error, Precision};
2
3/// Converts the digits of a string into
4/// eastings, northings and precision.
5pub fn digits(s: &str) -> Result<(u32, u32, Precision), Error> {
6    // Error is s length is over 10 or not even;
7    if s.len() > 10 || (s.len() % 2) != 0 {
8        return Err(Error::ParseError(format!(
9            "{} is not a valid number of digits. Supported values: 0, 2, 4, 6, 8, 10.",
10            s.len()
11        )));
12    }
13
14    let (eastings, northings) = {
15        if s.is_empty() {
16            (0, 0)
17        } else {
18            let (e, n) = s.split_at(s.len() / 2);
19
20            (
21                e.parse()
22                    .map_err(|e| Error::ParseError(format!("{:?}", e)))?,
23                n.parse()
24                    .map_err(|e| Error::ParseError(format!("{:?}", e)))?,
25            )
26        }
27    };
28
29    let precision = match s.len() {
30        0 => Precision::_100Km,
31        2 => Precision::_10Km,
32        4 => Precision::_1Km,
33        6 => Precision::_100M,
34        8 => Precision::_10M,
35        10 => Precision::_1M,
36        _ => {
37            return Err(Error::InvalidPrecision(format!(
38                "{} is not a valid number of digits. Supported values: 0, 2, 4, 6, 8, 10.",
39                s.len()
40            )))
41        }
42    };
43
44    Ok((
45        eastings * precision.metres(),
46        northings * precision.metres(),
47        precision,
48    ))
49}
50
51/// Removes all non-alphanumeric characters from string
52/// and converts to uppercase for parsing.
53pub fn trim_string(s: &str) -> String {
54    s.chars()
55        .filter(|c| !c.is_ascii_whitespace())
56        .map(|c| c.to_ascii_uppercase())
57        .collect()
58}
59
60#[cfg(test)]
61mod test {
62    use crate::{
63        constants::*,
64        utils::{digits, trim_string},
65        Error, Precision,
66    };
67
68    #[test]
69    fn parse_valid_digits() {
70        assert_eq!(digits(""), Ok((0, 0, Precision::_100Km)));
71        assert_eq!(digits("12"), Ok((_10KM, 20_000, Precision::_10Km)));
72        assert_eq!(digits("1234"), Ok((12_000, 34_000, Precision::_1Km)));
73        assert_eq!(digits("123456"), Ok((12_300, 45_600, Precision::_100M)));
74        assert_eq!(digits("12345678"), Ok((12_340, 56_780, Precision::_10M)));
75        assert_eq!(digits("0123456789"), Ok((01_234, 56_789, Precision::_1M)));
76    }
77
78    #[test]
79    fn reject_invalid_digits() {
80        // Reject wrong length
81        assert_eq!(
82            digits("123"),
83            Err(Error::ParseError(
84                "3 is not a valid number of digits. Supported values: 0, 2, 4, 6, 8, 10."
85                    .to_string()
86            ))
87        );
88
89        // Reject non numbers
90        assert_eq!(
91            digits("ab"),
92            Err(Error::ParseError(
93                "ParseIntError { kind: InvalidDigit }".to_string()
94            ))
95        )
96    }
97
98    #[test]
99    fn trim_strings() {
100        assert_eq!(trim_string("so 14 5"), "SO145");
101        assert_eq!(trim_string("So 222"), "SO222");
102        assert_eq!(trim_string(" @ @ "), "@@");
103    }
104}
gridish/utils.rs

gridish/
utils.rs
