Interface Input

regex/src/input.rs:79–112

An abstraction over input used in the matching engines.

/// An abstraction over input used in the matching engines.
pub trait Input {
    /// Return an encoding of the position at byte offset `i`.
    fn at(&self, i: usize) -> InputAt;

    /// Return the Unicode character occurring next to `at`.
    ///
    /// If no such character could be decoded, then `Char` is absent.
    fn next_char(&self, at: InputAt) -> Char;

    /// Return the Unicode character occurring previous to `at`.
    ///
    /// If no such character could be decoded, then `Char` is absent.
    fn previous_char(&self, at: InputAt) -> Char;

    /// Return true if the given empty width instruction matches at the
    /// input position given.
    fn is_empty_match(&self, at: InputAt, empty: &InstEmptyLook) -> bool;

    /// Scan the input for a matching prefix.
    fn prefix_at(
        &self,
        prefixes: &LiteralSearcher,
        at: InputAt,
    ) -> Option<InputAt>;

    /// The number of bytes in the input.
    fn len(&self) -> usize;

    /// Whether the input is empty.
    fn is_empty(&self) -> bool { self.len() == 0 }

    /// Return the given input as a sequence of bytes.
    fn as_bytes(&self) -> &[u8];
}

impl<'a, T: Input> Input for &'a T {
    fn at(&self, i: usize) -> InputAt { (**self).at(i) }