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use core::fmt;
/// The error type for decoding a hex string into `Vec<u8>` or `[u8; N]`.
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum FromHexError {
/// An invalid character was found. Valid ones are: `0...9`, `a...f`
/// or `A...F`.
InvalidHexCharacter { c: char, index: usize },
/// A hex string's length needs to be even, as two digits correspond to
/// one byte.
OddLength,
/// If the hex string is decoded into a fixed sized container, such as an
/// array, the hex string's length * 2 has to match the container's
/// length.
InvalidStringLength,
}
#[cfg(feature = "std")]
impl std::error::Error for FromHexError {}
impl fmt::Display for FromHexError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
FromHexError::InvalidHexCharacter { c, index } => {
write!(f, "Invalid character {:?} at position {}", c, index)
}
FromHexError::OddLength => write!(f, "Odd number of digits"),
FromHexError::InvalidStringLength => write!(f, "Invalid string length"),
}
}
}
#[cfg(test)]
// this feature flag is here to suppress unused
// warnings of `super::*` and `pretty_assertions::assert_eq`
#[cfg(feature = "alloc")]
mod tests {
use super::*;
#[cfg(feature = "alloc")]
use alloc::string::ToString;
use pretty_assertions::assert_eq;
#[test]
#[cfg(feature = "alloc")]
fn test_display() {
assert_eq!(
FromHexError::InvalidHexCharacter { c: '\n', index: 5 }.to_string(),
"Invalid character '\\n' at position 5"
);
assert_eq!(FromHexError::OddLength.to_string(), "Odd number of digits");
assert_eq!(
FromHexError::InvalidStringLength.to_string(),
"Invalid string length"
);
}
}