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use super::StringExt;
use std_::mem;
use std_::str::CharIndices;
#[inline(always)]
fn next_split<'a, P, T: Eq + Clone>(
pred: &mut P,
s: &mut &'a str,
last: &mut T,
) -> Option<KeyStr<'a, T>>
where
P: FnMut(char) -> T,
{
let mut next = last.clone();
if s.is_empty() {
return None;
}
let end = s
.find(|c| {
next = pred(c);
*last != next
})
.map_or(s.len(), |v| v);
let (ret, new_s) = s.split_at(end);
*s = new_s;
let key = mem::replace(last, next);
Some(KeyStr { str: ret, key })
}
#[inline(always)]
fn next_rsplit<'a, P, T: Eq + Clone>(
pred: &mut P,
s: &mut &'a str,
last: &mut T,
) -> Option<KeyStr<'a, T>>
where
P: FnMut(char) -> T,
{
let mut next = last.clone();
if s.is_empty() {
return None;
}
let left = s
.rfind(|c| {
next = pred(c);
*last != next
})
.map_or(0, |v| s.next_char_boundary(v));
let (new_s, ret) = s.split_at(left);
*s = new_s;
let key = mem::replace(last, next);
Some(KeyStr { str: ret, key })
}
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
pub struct KeyStr<'a, T> {
pub str: &'a str,
pub key: T,
}
impl<'a, T> KeyStr<'a, T> {
pub fn str(&self) -> &'a str {
self.str
}
pub fn into_pair(self)->(T,&'a str){
(self.key,self.str)
}
}
#[derive(Debug, Clone)]
pub struct SplitWhile<'a, P, T> {
pub(super) mapper: P,
pub(super) s: &'a str,
pub(super) last_left: T,
pub(super) last_right: T,
}
impl<'a, P, T: Eq + Clone> Iterator for SplitWhile<'a, P, T>
where
P: FnMut(char) -> T,
{
type Item = KeyStr<'a, T>;
fn next(&mut self) -> Option<Self::Item> {
next_split(&mut self.mapper, &mut self.s, &mut self.last_left)
}
}
impl<'a, P, T: Eq + Clone> DoubleEndedIterator for SplitWhile<'a, P, T>
where
P: FnMut(char) -> T,
{
fn next_back(&mut self) -> Option<Self::Item> {
next_rsplit(&mut self.mapper, &mut self.s, &mut self.last_right)
}
}
#[derive(Debug, Clone)]
pub struct RSplitWhile<'a, P, T> {
pub(super) mapper: P,
pub(super) s: &'a str,
pub(super) last_left: T,
pub(super) last_right: T,
}
impl<'a, P, T: Eq + Clone> Iterator for RSplitWhile<'a, P, T>
where
P: FnMut(char) -> T,
{
type Item = KeyStr<'a, T>;
fn next(&mut self) -> Option<Self::Item> {
next_rsplit(&mut self.mapper, &mut self.s, &mut self.last_right)
}
}
impl<'a, P, T: Eq + Clone> DoubleEndedIterator for RSplitWhile<'a, P, T>
where
P: FnMut(char) -> T,
{
fn next_back(&mut self) -> Option<Self::Item> {
next_split(&mut self.mapper, &mut self.s, &mut self.last_left)
}
}
#[derive(Clone, Debug)]
pub struct CharIndicesFrom<'a> {
pub(super) offset: usize,
pub(super) iter: CharIndices<'a>,
}
impl<'a> Iterator for CharIndicesFrom<'a> {
type Item = (usize, char);
#[inline]
fn next(&mut self) -> Option<(usize, char)> {
self.iter.next().map(|(i, c)| (i + self.offset, c))
}
#[inline]
fn count(self) -> usize {
self.iter.count()
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
self.iter.size_hint()
}
#[inline]
fn last(mut self) -> Option<(usize, char)> {
self.next_back()
}
}
impl<'a> DoubleEndedIterator for CharIndicesFrom<'a> {
#[inline]
fn next_back(&mut self) -> Option<(usize, char)> {
self.iter.next_back().map(|(i, c)| (i + self.offset, c))
}
}
impl<'a> CharIndicesFrom<'a> {
pub fn as_str(&self) -> &'a str {
self.iter.as_str()
}
}