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use crate::RopeSlice;
// TODO: switch to std::str::Pattern when it is stable.
pub trait CharMatcher {
fn char_match(&self, ch: char) -> bool;
}
impl CharMatcher for char {
fn char_match(&self, ch: char) -> bool {
*self == ch
}
}
impl<F: Fn(&char) -> bool> CharMatcher for F {
fn char_match(&self, ch: char) -> bool {
(*self)(&ch)
}
}
pub fn find_nth_next<M: CharMatcher>(
text: RopeSlice,
char_matcher: M,
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 char_matcher.char_match(c) {
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)
}
|
