618 lines
18 KiB
Rust
618 lines
18 KiB
Rust
use super::Point;
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use arrayvec::ArrayString;
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use smallvec::SmallVec;
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use std::{cmp, ops::Range, str};
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use sum_tree::{Bias, SumTree};
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#[cfg(test)]
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const CHUNK_BASE: usize = 6;
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#[cfg(not(test))]
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const CHUNK_BASE: usize = 16;
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#[derive(Clone, Default, Debug)]
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pub struct Rope {
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chunks: SumTree<Chunk>,
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}
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impl Rope {
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pub fn new() -> Self {
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Self::default()
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}
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pub fn append(&mut self, rope: Rope) {
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let mut chunks = rope.chunks.cursor::<()>();
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chunks.next(&());
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if let Some(chunk) = chunks.item() {
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if self.chunks.last().map_or(false, |c| c.0.len() < CHUNK_BASE)
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|| chunk.0.len() < CHUNK_BASE
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{
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self.push(&chunk.0);
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chunks.next(&());
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}
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}
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self.chunks.push_tree(chunks.suffix(&()), &());
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self.check_invariants();
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}
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pub fn push(&mut self, text: &str) {
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let mut new_chunks = SmallVec::<[_; 16]>::new();
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let mut new_chunk = ArrayString::new();
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for ch in text.chars() {
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if new_chunk.len() + ch.len_utf8() > 2 * CHUNK_BASE {
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new_chunks.push(Chunk(new_chunk));
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new_chunk = ArrayString::new();
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}
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new_chunk.push(ch);
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}
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if !new_chunk.is_empty() {
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new_chunks.push(Chunk(new_chunk));
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}
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let mut new_chunks = new_chunks.into_iter();
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let mut first_new_chunk = new_chunks.next();
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self.chunks.update_last(
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|last_chunk| {
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if let Some(first_new_chunk_ref) = first_new_chunk.as_mut() {
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if last_chunk.0.len() + first_new_chunk_ref.0.len() <= 2 * CHUNK_BASE {
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last_chunk.0.push_str(&first_new_chunk.take().unwrap().0);
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} else {
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let mut text = ArrayString::<{ 4 * CHUNK_BASE }>::new();
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text.push_str(&last_chunk.0);
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text.push_str(&first_new_chunk_ref.0);
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let (left, right) = text.split_at(find_split_ix(&text));
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last_chunk.0.clear();
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last_chunk.0.push_str(left);
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first_new_chunk_ref.0.clear();
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first_new_chunk_ref.0.push_str(right);
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}
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}
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},
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&(),
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);
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self.chunks
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.extend(first_new_chunk.into_iter().chain(new_chunks), &());
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self.check_invariants();
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}
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fn check_invariants(&self) {
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#[cfg(test)]
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{
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// Ensure all chunks except maybe the last one are not underflowing.
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// Allow some wiggle room for multibyte characters at chunk boundaries.
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let mut chunks = self.chunks.cursor::<()>().peekable();
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while let Some(chunk) = chunks.next() {
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if chunks.peek().is_some() {
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assert!(chunk.0.len() + 3 >= CHUNK_BASE);
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}
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}
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}
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}
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pub fn summary(&self) -> TextSummary {
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self.chunks.summary()
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}
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pub fn len(&self) -> usize {
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self.chunks.extent(&())
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}
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pub fn max_point(&self) -> Point {
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self.chunks.extent(&())
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}
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pub fn cursor(&self, offset: usize) -> Cursor {
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Cursor::new(self, offset)
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}
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pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
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self.chars_at(0)
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}
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pub fn chars_at(&self, start: usize) -> impl Iterator<Item = char> + '_ {
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self.chunks_in_range(start..self.len()).flat_map(str::chars)
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}
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pub fn bytes_at(&self, start: usize) -> impl Iterator<Item = u8> + '_ {
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self.chunks_in_range(start..self.len()).flat_map(str::bytes)
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}
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pub fn chunks<'a>(&'a self) -> Chunks<'a> {
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self.chunks_in_range(0..self.len())
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}
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pub fn chunks_in_range<'a>(&'a self, range: Range<usize>) -> Chunks<'a> {
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Chunks::new(self, range)
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}
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pub fn to_point(&self, offset: usize) -> Point {
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assert!(offset <= self.summary().bytes);
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let mut cursor = self.chunks.cursor::<(usize, Point)>();
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cursor.seek(&offset, Bias::Left, &());
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let overshoot = offset - cursor.start().0;
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cursor.start().1
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+ cursor
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.item()
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.map_or(Point::zero(), |chunk| chunk.to_point(overshoot))
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}
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pub fn to_offset(&self, point: Point) -> usize {
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assert!(point <= self.summary().lines);
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let mut cursor = self.chunks.cursor::<(Point, usize)>();
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cursor.seek(&point, Bias::Left, &());
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let overshoot = point - cursor.start().0;
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cursor.start().1 + cursor.item().map_or(0, |chunk| chunk.to_offset(overshoot))
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}
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pub fn clip_offset(&self, mut offset: usize, bias: Bias) -> usize {
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let mut cursor = self.chunks.cursor::<usize>();
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cursor.seek(&offset, Bias::Left, &());
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if let Some(chunk) = cursor.item() {
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let mut ix = offset - cursor.start();
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while !chunk.0.is_char_boundary(ix) {
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match bias {
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Bias::Left => {
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ix -= 1;
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offset -= 1;
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}
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Bias::Right => {
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ix += 1;
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offset += 1;
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}
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}
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}
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offset
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} else {
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self.summary().bytes
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}
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}
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pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
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let mut cursor = self.chunks.cursor::<Point>();
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cursor.seek(&point, Bias::Right, &());
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if let Some(chunk) = cursor.item() {
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let overshoot = point - cursor.start();
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*cursor.start() + chunk.clip_point(overshoot, bias)
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} else {
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self.summary().lines
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}
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}
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}
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impl<'a> From<&'a str> for Rope {
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fn from(text: &'a str) -> Self {
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let mut rope = Self::new();
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rope.push(text);
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rope
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}
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}
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impl Into<String> for Rope {
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fn into(self) -> String {
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self.chunks().collect()
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}
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}
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pub struct Cursor<'a> {
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rope: &'a Rope,
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chunks: sum_tree::Cursor<'a, Chunk, usize>,
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offset: usize,
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}
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impl<'a> Cursor<'a> {
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pub fn new(rope: &'a Rope, offset: usize) -> Self {
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let mut chunks = rope.chunks.cursor();
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chunks.seek(&offset, Bias::Right, &());
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Self {
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rope,
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chunks,
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offset,
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}
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}
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pub fn seek_forward(&mut self, end_offset: usize) {
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debug_assert!(end_offset >= self.offset);
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self.chunks.seek_forward(&end_offset, Bias::Right, &());
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self.offset = end_offset;
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}
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pub fn slice(&mut self, end_offset: usize) -> Rope {
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debug_assert!(
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end_offset >= self.offset,
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"cannot slice backwards from {} to {}",
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self.offset,
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end_offset
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);
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let mut slice = Rope::new();
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if let Some(start_chunk) = self.chunks.item() {
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let start_ix = self.offset - self.chunks.start();
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let end_ix = cmp::min(end_offset, self.chunks.end(&())) - self.chunks.start();
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slice.push(&start_chunk.0[start_ix..end_ix]);
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}
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if end_offset > self.chunks.end(&()) {
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self.chunks.next(&());
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slice.append(Rope {
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chunks: self.chunks.slice(&end_offset, Bias::Right, &()),
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});
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if let Some(end_chunk) = self.chunks.item() {
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let end_ix = end_offset - self.chunks.start();
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slice.push(&end_chunk.0[..end_ix]);
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}
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}
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self.offset = end_offset;
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slice
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}
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pub fn summary(&mut self, end_offset: usize) -> TextSummary {
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debug_assert!(end_offset >= self.offset);
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let mut summary = TextSummary::default();
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if let Some(start_chunk) = self.chunks.item() {
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let start_ix = self.offset - self.chunks.start();
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let end_ix = cmp::min(end_offset, self.chunks.end(&())) - self.chunks.start();
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summary = TextSummary::from(&start_chunk.0[start_ix..end_ix]);
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}
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if end_offset > self.chunks.end(&()) {
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self.chunks.next(&());
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summary += &self.chunks.summary(&end_offset, Bias::Right, &());
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if let Some(end_chunk) = self.chunks.item() {
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let end_ix = end_offset - self.chunks.start();
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summary += TextSummary::from(&end_chunk.0[..end_ix]);
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}
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}
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self.offset = end_offset;
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summary
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}
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pub fn suffix(mut self) -> Rope {
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self.slice(self.rope.chunks.extent(&()))
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}
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pub fn offset(&self) -> usize {
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self.offset
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}
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}
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pub struct Chunks<'a> {
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chunks: sum_tree::Cursor<'a, Chunk, usize>,
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range: Range<usize>,
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}
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impl<'a> Chunks<'a> {
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pub fn new(rope: &'a Rope, range: Range<usize>) -> Self {
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let mut chunks = rope.chunks.cursor();
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chunks.seek(&range.start, Bias::Right, &());
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Self { chunks, range }
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}
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pub fn offset(&self) -> usize {
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self.range.start.max(*self.chunks.start())
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}
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pub fn seek(&mut self, offset: usize) {
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if offset >= self.chunks.end(&()) {
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self.chunks.seek_forward(&offset, Bias::Right, &());
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} else {
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self.chunks.seek(&offset, Bias::Right, &());
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}
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self.range.start = offset;
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}
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pub fn peek(&self) -> Option<&'a str> {
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if let Some(chunk) = self.chunks.item() {
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let offset = *self.chunks.start();
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if self.range.end > offset {
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let start = self.range.start.saturating_sub(*self.chunks.start());
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let end = self.range.end - self.chunks.start();
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return Some(&chunk.0[start..chunk.0.len().min(end)]);
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}
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}
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None
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}
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}
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impl<'a> Iterator for Chunks<'a> {
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type Item = &'a str;
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fn next(&mut self) -> Option<Self::Item> {
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let result = self.peek();
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if result.is_some() {
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self.chunks.next(&());
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}
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result
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}
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}
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#[derive(Clone, Debug, Default)]
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struct Chunk(ArrayString<{ 2 * CHUNK_BASE }>);
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impl Chunk {
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fn to_point(&self, target: usize) -> Point {
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let mut offset = 0;
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let mut point = Point::new(0, 0);
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for ch in self.0.chars() {
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if offset >= target {
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break;
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}
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if ch == '\n' {
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point.row += 1;
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point.column = 0;
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} else {
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point.column += ch.len_utf8() as u32;
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}
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offset += ch.len_utf8();
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}
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point
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}
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fn to_offset(&self, target: Point) -> usize {
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let mut offset = 0;
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let mut point = Point::new(0, 0);
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for ch in self.0.chars() {
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if point >= target {
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if point > target {
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panic!("point {:?} is inside of character {:?}", target, ch);
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}
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break;
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}
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if ch == '\n' {
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point.row += 1;
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point.column = 0;
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} else {
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point.column += ch.len_utf8() as u32;
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}
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offset += ch.len_utf8();
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}
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offset
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}
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fn clip_point(&self, target: Point, bias: Bias) -> Point {
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for (row, line) in self.0.split('\n').enumerate() {
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if row == target.row as usize {
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let mut column = target.column.min(line.len() as u32);
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while !line.is_char_boundary(column as usize) {
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match bias {
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Bias::Left => column -= 1,
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Bias::Right => column += 1,
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}
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}
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return Point::new(row as u32, column);
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}
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}
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unreachable!()
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}
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}
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impl sum_tree::Item for Chunk {
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type Summary = TextSummary;
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fn summary(&self) -> Self::Summary {
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TextSummary::from(self.0.as_str())
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}
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}
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#[derive(Clone, Debug, Default, Eq, PartialEq)]
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pub struct TextSummary {
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pub bytes: usize,
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pub lines: Point,
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pub first_line_chars: u32,
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pub last_line_chars: u32,
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pub longest_row: u32,
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pub longest_row_chars: u32,
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}
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impl<'a> From<&'a str> for TextSummary {
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fn from(text: &'a str) -> Self {
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let mut lines = Point::new(0, 0);
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let mut first_line_chars = 0;
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let mut last_line_chars = 0;
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let mut longest_row = 0;
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let mut longest_row_chars = 0;
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for c in text.chars() {
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if c == '\n' {
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lines.row += 1;
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lines.column = 0;
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last_line_chars = 0;
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} else {
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lines.column += c.len_utf8() as u32;
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last_line_chars += 1;
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}
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if lines.row == 0 {
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first_line_chars = last_line_chars;
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}
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if last_line_chars > longest_row_chars {
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longest_row = lines.row;
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longest_row_chars = last_line_chars;
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}
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}
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TextSummary {
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bytes: text.len(),
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lines,
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first_line_chars,
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last_line_chars,
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longest_row,
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longest_row_chars,
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}
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}
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}
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impl sum_tree::Summary for TextSummary {
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type Context = ();
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fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
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*self += summary;
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}
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}
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impl<'a> std::ops::AddAssign<&'a Self> for TextSummary {
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fn add_assign(&mut self, other: &'a Self) {
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let joined_chars = self.last_line_chars + other.first_line_chars;
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if joined_chars > self.longest_row_chars {
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self.longest_row = self.lines.row;
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self.longest_row_chars = joined_chars;
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}
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if other.longest_row_chars > self.longest_row_chars {
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self.longest_row = self.lines.row + other.longest_row;
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self.longest_row_chars = other.longest_row_chars;
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}
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if self.lines.row == 0 {
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self.first_line_chars += other.first_line_chars;
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}
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if other.lines.row == 0 {
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self.last_line_chars += other.first_line_chars;
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} else {
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self.last_line_chars = other.last_line_chars;
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}
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self.bytes += other.bytes;
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self.lines += &other.lines;
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}
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}
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impl std::ops::AddAssign<Self> for TextSummary {
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fn add_assign(&mut self, other: Self) {
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*self += &other;
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}
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}
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impl<'a> sum_tree::Dimension<'a, TextSummary> for usize {
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fn add_summary(&mut self, summary: &'a TextSummary, _: &()) {
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*self += summary.bytes;
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}
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}
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impl<'a> sum_tree::Dimension<'a, TextSummary> for Point {
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fn add_summary(&mut self, summary: &'a TextSummary, _: &()) {
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*self += &summary.lines;
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}
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}
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fn find_split_ix(text: &str) -> usize {
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let mut ix = text.len() / 2;
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while !text.is_char_boundary(ix) {
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if ix < 2 * CHUNK_BASE {
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ix += 1;
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} else {
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ix = (text.len() / 2) - 1;
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break;
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}
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}
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while !text.is_char_boundary(ix) {
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ix -= 1;
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}
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debug_assert!(ix <= 2 * CHUNK_BASE);
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debug_assert!(text.len() - ix <= 2 * CHUNK_BASE);
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ix
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::random_char_iter::RandomCharIter;
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use rand::prelude::*;
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use std::env;
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use Bias::{Left, Right};
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#[test]
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fn test_all_4_byte_chars() {
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let mut rope = Rope::new();
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let text = "🏀".repeat(256);
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rope.push(&text);
|
|
assert_eq!(rope.text(), text);
|
|
}
|
|
|
|
#[gpui::test(iterations = 100)]
|
|
fn test_random(mut rng: StdRng) {
|
|
let operations = env::var("OPERATIONS")
|
|
.map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
|
|
.unwrap_or(10);
|
|
|
|
let mut expected = String::new();
|
|
let mut actual = Rope::new();
|
|
for _ in 0..operations {
|
|
let end_ix = clip_offset(&expected, rng.gen_range(0..=expected.len()), Right);
|
|
let start_ix = clip_offset(&expected, rng.gen_range(0..=end_ix), Left);
|
|
let len = rng.gen_range(0..=64);
|
|
let new_text: String = RandomCharIter::new(&mut rng).take(len).collect();
|
|
|
|
let mut new_actual = Rope::new();
|
|
let mut cursor = actual.cursor(0);
|
|
new_actual.append(cursor.slice(start_ix));
|
|
new_actual.push(&new_text);
|
|
cursor.seek_forward(end_ix);
|
|
new_actual.append(cursor.suffix());
|
|
actual = new_actual;
|
|
|
|
expected.replace_range(start_ix..end_ix, &new_text);
|
|
|
|
assert_eq!(actual.text(), expected);
|
|
log::info!("text: {:?}", expected);
|
|
|
|
for _ in 0..5 {
|
|
let end_ix = clip_offset(&expected, rng.gen_range(0..=expected.len()), Right);
|
|
let start_ix = clip_offset(&expected, rng.gen_range(0..=end_ix), Left);
|
|
assert_eq!(
|
|
actual.chunks_in_range(start_ix..end_ix).collect::<String>(),
|
|
&expected[start_ix..end_ix]
|
|
);
|
|
}
|
|
|
|
let mut point = Point::new(0, 0);
|
|
for (ix, ch) in expected.char_indices().chain(Some((expected.len(), '\0'))) {
|
|
assert_eq!(actual.to_point(ix), point, "to_point({})", ix);
|
|
assert_eq!(actual.to_offset(point), ix, "to_offset({:?})", point);
|
|
if ch == '\n' {
|
|
point.row += 1;
|
|
point.column = 0
|
|
} else {
|
|
point.column += ch.len_utf8() as u32;
|
|
}
|
|
}
|
|
|
|
for _ in 0..5 {
|
|
let end_ix = clip_offset(&expected, rng.gen_range(0..=expected.len()), Right);
|
|
let start_ix = clip_offset(&expected, rng.gen_range(0..=end_ix), Left);
|
|
assert_eq!(
|
|
actual.cursor(start_ix).summary(end_ix),
|
|
TextSummary::from(&expected[start_ix..end_ix])
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn clip_offset(text: &str, mut offset: usize, bias: Bias) -> usize {
|
|
while !text.is_char_boundary(offset) {
|
|
match bias {
|
|
Bias::Left => offset -= 1,
|
|
Bias::Right => offset += 1,
|
|
}
|
|
}
|
|
offset
|
|
}
|
|
|
|
impl Rope {
|
|
fn text(&self) -> String {
|
|
let mut text = String::new();
|
|
for chunk in self.chunks.cursor::<()>() {
|
|
text.push_str(&chunk.0);
|
|
}
|
|
text
|
|
}
|
|
}
|
|
}
|