helix-plus/helix-core/src/search.rs

use crate::RopeSlice;

pub fn find_nth_next(text: RopeSlice, ch: char, mut pos: usize, n: usize) -> Option<usize> {
    if pos >= text.len_chars() || n == 0 {
        return None;
    }

    let mut chars = text.chars_at(pos);

    for _ in 0..n {
        loop {
            let c = chars.next()?;

            pos += 1;

            if c == ch {
                break;
            }
        }
    }

    Some(pos - 1)
}

pub fn find_nth_prev(text: RopeSlice, ch: char, mut pos: usize, n: usize) -> Option<usize> {
    if pos == 0 || n == 0 {
        return None;
    }

    let mut chars = text.chars_at(pos);

    for _ in 0..n {
        loop {
            let c = chars.prev()?;

            pos -= 1;

            if c == ch {
                break;
            }
        }
    }

    Some(pos)
}