100 lines
2.2 KiB
Rust
100 lines
2.2 KiB
Rust
use std::num::TryFromIntError;
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use thiserror::Error;
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macro_rules! octal_digit {
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($digit:expr) => {
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match $digit {
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'0' => Ok(0),
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'1' => Ok(1),
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'2' => Ok(2),
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'3' => Ok(3),
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'4' => Ok(4),
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'5' => Ok(5),
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'6' => Ok(6),
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'7' => Ok(7),
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_ => Err(OctalError::InvalidCharacter($digit)),
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}
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};
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}
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#[derive(Debug, Error, Clone)]
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pub enum OctalError {
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#[error("invalid/non-octal character: [{0}]")]
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InvalidCharacter(char),
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#[error("try_from_int failed: [{0}]")]
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TryFromIntError(#[from] TryFromIntError),
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}
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pub trait FromOctal: Sized {
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fn from_octal(octal: &str) -> Result<Self, OctalError>;
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}
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pub trait ParseOctal<T> {
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fn parse_octal(&self) -> Result<T, OctalError>;
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}
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impl<T, V: AsRef<str>> ParseOctal<T> for V
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where
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T: FromOctal,
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{
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fn parse_octal(&self) -> Result<T, OctalError> {
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T::from_octal(self.as_ref())
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}
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}
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macro_rules! impl_from_octal {
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($ty:ty) => {
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impl FromOctal for $ty {
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fn from_octal(octal: &str) -> Result<Self, OctalError> {
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if let Some(without_prefix) = octal.strip_prefix("0o") {
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return Self::from_octal(without_prefix);
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}
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Ok(octal
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.chars()
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.map(|c| octal_digit!(c))
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.collect::<Result<Vec<_>, _>>()?
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.into_iter()
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.rev()
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.enumerate()
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.map(|(idx, value)| -> Result<_, TryFromIntError> {
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Ok((8 as $ty).pow(idx.try_into()?) * value)
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})
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.collect::<Result<Vec<_>, _>>()?
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.into_iter()
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.sum())
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}
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}
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};
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($($ty:ty),+) => {
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$(
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impl_from_octal!($ty);
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)+
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};
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}
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impl_from_octal!(i8, i16, i32, i64, u8, u16, u32, u64);
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#[cfg(test)]
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mod test {
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use super::FromOctal;
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macro_rules! octal {
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($val:literal) => {
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(stringify!($val), $val as u32)
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};
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}
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#[test]
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fn test_hex_parse() {
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for (str, expected) in [
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octal!(0o15),
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octal!(0o777),
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octal!(0o1337),
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octal!(0o0),
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octal!(0o10),
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] {
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let actual = u32::from_octal(str).expect("from_hex");
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assert_eq!(expected, actual);
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}
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}
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}
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