scolapasta_int_parse/
subject.rs

1use crate::error::ArgumentError;
2
3#[derive(Default, Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
4pub struct IntegerString<'a>(&'a [u8]);
5
6impl<'a> TryFrom<&'a [u8]> for IntegerString<'a> {
7    type Error = ArgumentError<'a>;
8
9    fn try_from(subject: &'a [u8]) -> Result<Self, Self::Error> {
10        if !subject.is_ascii() {
11            return Err(subject.into());
12        }
13        if subject.contains(&b'\0') {
14            return Err(subject.into());
15        }
16        Ok(Self(subject))
17    }
18}
19
20impl<'a> TryFrom<&'a str> for IntegerString<'a> {
21    type Error = ArgumentError<'a>;
22
23    fn try_from(to_parse: &'a str) -> Result<Self, Self::Error> {
24        to_parse.as_bytes().try_into()
25    }
26}
27
28impl<'a> From<IntegerString<'a>> for &'a [u8] {
29    #[inline]
30    fn from(subject: IntegerString<'a>) -> &'a [u8] {
31        subject.as_bytes()
32    }
33}
34
35impl<'a> IntegerString<'a> {
36    /// Constructs a new, empty `IntegerString`.
37    #[inline]
38    #[must_use]
39    pub const fn new() -> Self {
40        Self(b"")
41    }
42
43    /// Try to construct an `IntegerString` from the given byte slice.
44    ///
45    /// This conversion is fallible and requires the subject to be ASCII and
46    /// have no NUL bytes.
47    ///
48    /// This conversion is also available as a [`TryFrom`] conversion which
49    /// returns [`ArgumentError`] in the failure case.
50    #[must_use]
51    pub fn from_slice(subject: &'a [u8]) -> Option<Self> {
52        subject.try_into().ok()
53    }
54
55    /// Retrieve the inner byte string from the `IntegerString`.
56    #[inline]
57    #[must_use]
58    pub fn as_bytes(self) -> &'a [u8] {
59        self.0
60    }
61}
62
63#[cfg(test)]
64mod tests {
65    use super::IntegerString;
66
67    #[test]
68    fn nul_byte_is_err() {
69        IntegerString::try_from("\0").unwrap_err();
70        IntegerString::try_from("123\0").unwrap_err();
71        IntegerString::try_from("123\x00456").unwrap_err();
72    }
73
74    #[test]
75    fn emoji_is_err() {
76        IntegerString::try_from("🕐").unwrap_err();
77    }
78
79    #[test]
80    fn invalid_utf8_is_err() {
81        IntegerString::try_from(&b"\xFF"[..]).unwrap_err();
82    }
83}
scolapasta_int_parse/subject.rs

scolapasta_int_parse/
subject.rs
