WIP: Switch to byte-oriented indexing

Co-Authored-By: Nathan Sobo <nathan@zed.dev>
This commit is contained in:
Antonio Scandurra 2021-05-17 18:01:08 +02:00
parent 529a42e78f
commit f7691fc00c
2 changed files with 80 additions and 70 deletions

View file

@ -1,6 +1,5 @@
use super::Point;
use crate::sum_tree::{self, SeekBias, SumTree};
use crate::util::byte_range_for_char_range;
use anyhow::{anyhow, Result};
use arrayvec::ArrayString;
use smallvec::SmallVec;
@ -125,31 +124,54 @@ impl Rope {
ChunksIter::new(self, range)
}
pub fn to_point(&self, offset: usize) -> Result<Point> {
if offset <= self.summary().chars {
let mut cursor = self.chunks.cursor::<usize, TextSummary>();
cursor.seek(&offset, SeekBias::Left, &());
let overshoot = offset - cursor.start().chars;
Ok(cursor.start().lines
+ cursor
.item()
.map_or(Point::zero(), |chunk| chunk.to_point(overshoot)))
pub fn to_point(&self, offset: usize) -> Point {
assert!(offset <= self.summary().bytes);
let mut cursor = self.chunks.cursor::<usize, TextSummary>();
cursor.seek(&offset, SeekBias::Left, &());
let overshoot = offset - cursor.start().bytes;
cursor.start().lines
+ cursor
.item()
.map_or(Point::zero(), |chunk| chunk.to_point(overshoot))
}
pub fn to_offset(&self, point: Point) -> usize {
assert!(point <= self.summary().lines);
let mut cursor = self.chunks.cursor::<Point, TextSummary>();
cursor.seek(&point, SeekBias::Left, &());
let overshoot = point - cursor.start().lines;
cursor.start().bytes + cursor.item().map_or(0, |chunk| chunk.to_offset(overshoot))
}
pub fn next_char_boundary(&self, mut offset: usize) -> usize {
assert!(offset <= self.summary().bytes);
let mut cursor = self.chunks.cursor::<usize, usize>();
cursor.seek(&offset, SeekBias::Left, &());
if let Some(chunk) = cursor.item() {
let ix = offset - cursor.start();
while !chunk.0.is_char_boundary(ix) {
ix += 1;
offset += 1;
}
offset
} else {
Err(anyhow!("offset out of bounds"))
offset
}
}
pub fn to_offset(&self, point: Point) -> Result<usize> {
if point <= self.summary().lines {
let mut cursor = self.chunks.cursor::<Point, TextSummary>();
cursor.seek(&point, SeekBias::Left, &());
let overshoot = point - cursor.start().lines;
Ok(cursor.start().chars
+ cursor
.item()
.map_or(Ok(0), |chunk| chunk.to_offset(overshoot))?)
pub fn prev_char_boundary(&self, offset: usize) -> usize {
assert!(offset <= self.summary().bytes);
let mut cursor = self.chunks.cursor::<usize, usize>();
cursor.seek(&offset, SeekBias::Left, &());
if let Some(chunk) = cursor.item() {
let ix = offset - cursor.start();
while !chunk.0.is_char_boundary(ix) {
ix -= 1;
offset -= 1;
}
offset
} else {
Err(anyhow!("offset out of bounds"))
offset
}
}
}
@ -193,8 +215,7 @@ impl<'a> Cursor<'a> {
if let Some(start_chunk) = self.chunks.item() {
let start_ix = self.offset - self.chunks.start();
let end_ix = cmp::min(end_offset, self.chunks.end()) - self.chunks.start();
let byte_range = byte_range_for_char_range(start_chunk.0, start_ix..end_ix);
slice.push(&start_chunk.0[byte_range]);
slice.push(&start_chunk.0[start_ix..end_ix]);
}
if end_offset > self.chunks.end() {
@ -204,8 +225,7 @@ impl<'a> Cursor<'a> {
});
if let Some(end_chunk) = self.chunks.item() {
let end_ix = end_offset - self.chunks.start();
let byte_range = byte_range_for_char_range(end_chunk.0, 0..end_ix);
slice.push(&end_chunk.0[byte_range]);
slice.push(&end_chunk.0[..end_ix]);
}
}
@ -220,8 +240,7 @@ impl<'a> Cursor<'a> {
if let Some(start_chunk) = self.chunks.item() {
let start_ix = self.offset - self.chunks.start();
let end_ix = cmp::min(end_offset, self.chunks.end()) - self.chunks.start();
let byte_range = byte_range_for_char_range(start_chunk.0, start_ix..end_ix);
summary = TextSummary::from(&start_chunk.0[byte_range]);
summary = TextSummary::from(&start_chunk.0[start_ix..end_ix]);
}
if end_offset > self.chunks.end() {
@ -229,8 +248,7 @@ impl<'a> Cursor<'a> {
summary += &self.chunks.summary(&end_offset, SeekBias::Right, &());
if let Some(end_chunk) = self.chunks.item() {
let end_ix = end_offset - self.chunks.start();
let byte_range = byte_range_for_char_range(end_chunk.0, 0..end_ix);
summary += TextSummary::from(&end_chunk.0[byte_range]);
summary += TextSummary::from(&end_chunk.0[..end_ix]);
}
}
@ -268,9 +286,8 @@ impl<'a> Iterator for ChunksIter<'a> {
} else if let Some(chunk) = self.chunks.item() {
let start = self.range.start.saturating_sub(*self.chunks.start());
let end = self.range.end - self.chunks.start();
let byte_range = byte_range_for_char_range(&chunk.0, start..end);
self.chunks.next();
Some(&chunk.0[byte_range])
Some(&chunk.0[start..end])
} else {
None
}
@ -293,14 +310,14 @@ impl Chunk {
point.row += 1;
point.column = 0;
} else {
point.column += 1;
point.column += ch.len_utf8() as u32;
}
offset += 1;
offset += ch.len_utf8();
}
point
}
fn to_offset(&self, target: Point) -> Result<usize> {
fn to_offset(&self, target: Point) -> usize {
let mut offset = 0;
let mut point = Point::new(0, 0);
for ch in self.0.chars() {
@ -312,16 +329,13 @@ impl Chunk {
point.row += 1;
point.column = 0;
} else {
point.column += 1;
point.column += ch.len_utf8() as u32;
}
offset += 1;
offset += ch.len_utf8();
}
if point == target {
Ok(offset)
} else {
Err(anyhow!("point out of bounds"))
}
assert_eq!(point, target);
offset
}
}
@ -335,7 +349,6 @@ impl sum_tree::Item for Chunk {
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct TextSummary {
pub chars: usize,
pub bytes: usize,
pub lines: Point,
pub first_line_len: u32,
@ -345,18 +358,15 @@ pub struct TextSummary {
impl<'a> From<&'a str> for TextSummary {
fn from(text: &'a str) -> Self {
let mut chars = 0;
let mut bytes = 0;
let mut lines = Point::new(0, 0);
let mut first_line_len = 0;
let mut rightmost_point = Point::new(0, 0);
for c in text.chars() {
chars += 1;
bytes += c.len_utf8();
if c == '\n' {
lines.row += 1;
lines.column = 0;
} else {
lines.column += 1;
lines.column += c.len_utf8() as u32;
if lines.row == 0 {
first_line_len = lines.column;
}
@ -367,8 +377,7 @@ impl<'a> From<&'a str> for TextSummary {
}
TextSummary {
chars,
bytes,
bytes: text.len(),
lines,
first_line_len,
rightmost_point,
@ -398,7 +407,6 @@ impl<'a> std::ops::AddAssign<&'a Self> for TextSummary {
self.first_line_len += other.first_line_len;
}
self.chars += other.chars;
self.bytes += other.bytes;
self.lines += &other.lines;
}
@ -418,7 +426,7 @@ impl<'a> sum_tree::Dimension<'a, TextSummary> for TextSummary {
impl<'a> sum_tree::Dimension<'a, TextSummary> for usize {
fn add_summary(&mut self, summary: &'a TextSummary) {
*self += summary.chars;
*self += summary.bytes;
}
}
@ -439,6 +447,7 @@ impl<'a> Chars<'a> {
cursor.seek(&start, SeekBias::Left, &());
let chars = if let Some(chunk) = cursor.item() {
let ix = start - cursor.start();
assert_char_boundary(&chunk.0, ix);
cursor.next();
chunk.0.chars().skip(ix)
} else {
@ -484,6 +493,23 @@ fn find_split_ix(text: &str) -> usize {
ix
}
#[inline(always)]
fn assert_char_boundary(s: &str, ix: usize) {
if !s.is_char_boundary(ix) {
let mut char_start = ix;
while !s.is_char_boundary(char_start) {
char_start -= 1;
}
let ch = s[char_start..].chars().next().unwrap();
let char_range = char_start..char_start + ch.len_utf8();
panic!(
"byte index {} is not a char boundary; it is inside {:?} (bytes {:?}) of `{}`",
ix, ch, char_range, s
);
}
}
#[cfg(test)]
mod tests {
use crate::util::RandomCharIter;
@ -521,8 +547,8 @@ mod tests {
let mut expected = String::new();
let mut actual = Rope::new();
for _ in 0..operations {
let end_ix = rng.gen_range(0..=expected.chars().count());
let start_ix = rng.gen_range(0..=end_ix);
let end_ix = actual.next_char_boundary(rng.gen_range(0..=expected.len()));
let start_ix = actual.prev_char_boundary(rng.gen_range(0..=end_ix));
let len = rng.gen_range(0..=64);
let new_text: String = RandomCharIter::new(&mut rng).take(len).collect();
@ -559,8 +585,8 @@ mod tests {
let mut point = Point::new(0, 0);
let mut offset = 0;
for ch in expected.chars() {
assert_eq!(actual.to_point(offset).unwrap(), point);
assert_eq!(actual.to_offset(point).unwrap(), offset);
assert_eq!(actual.to_point(offset), point);
assert_eq!(actual.to_offset(point), offset);
if ch == '\n' {
assert!(actual
.to_offset(Point::new(point.row, point.column + 1))
@ -581,7 +607,6 @@ mod tests {
for _ in 0..5 {
let end_ix = rng.gen_range(0..=expected.chars().count());
let start_ix = rng.gen_range(0..=end_ix);
let byte_range = byte_range_for_char_range(&expected, start_ix..end_ix);
assert_eq!(
actual.cursor(start_ix).summary(end_ix),
TextSummary::from(&expected[byte_range])

View file

@ -1,21 +1,6 @@
use rand::prelude::*;
use std::{cmp::Ordering, ops::Range};
pub fn byte_range_for_char_range(text: impl AsRef<str>, char_range: Range<usize>) -> Range<usize> {
let text = text.as_ref();
let mut result = text.len()..text.len();
for (i, (offset, _)) in text.char_indices().enumerate() {
if i == char_range.start {
result.start = offset;
}
if i == char_range.end {
result.end = offset;
break;
}
}
result
}
pub fn post_inc(value: &mut usize) -> usize {
let prev = *value;
*value += 1;