ZIm/crates/rope/src/chunk.rs
2025-08-26 19:50:54 +01:00

950 lines
29 KiB
Rust

use crate::{OffsetUtf16, Point, PointUtf16, TextSummary, Unclipped};
use arrayvec::ArrayString;
use std::{cmp, ops::Range};
use sum_tree::Bias;
use unicode_segmentation::GraphemeCursor;
use util::debug_panic;
pub(crate) const MIN_BASE: usize = if cfg!(test) { 6 } else { 64 };
pub(crate) const MAX_BASE: usize = MIN_BASE * 2;
#[derive(Clone, Debug, Default)]
pub struct Chunk {
chars: u128,
chars_utf16: u128,
newlines: u128,
pub tabs: u128,
pub text: ArrayString<MAX_BASE>,
}
impl Chunk {
#[inline(always)]
pub fn new(text: &str) -> Self {
let mut this = Chunk::default();
this.push_str(text);
this
}
#[inline(always)]
pub fn push_str(&mut self, text: &str) {
for (char_ix, c) in text.char_indices() {
let ix = self.text.len() + char_ix;
self.chars |= 1 << ix;
self.chars_utf16 |= 1 << ix;
self.chars_utf16 |= (c.len_utf16() as u128) << ix;
self.newlines |= ((c == '\n') as u128) << ix;
self.tabs |= ((c == '\t') as u128) << ix;
}
self.text.push_str(text);
}
#[inline(always)]
pub fn append(&mut self, slice: ChunkSlice) {
if slice.is_empty() {
return;
};
let base_ix = self.text.len();
self.chars |= slice.chars << base_ix;
self.chars_utf16 |= slice.chars_utf16 << base_ix;
self.newlines |= slice.newlines << base_ix;
self.tabs |= slice.tabs << base_ix;
self.text.push_str(slice.text);
}
#[inline(always)]
pub fn as_slice(&self) -> ChunkSlice<'_> {
ChunkSlice {
chars: self.chars,
chars_utf16: self.chars_utf16,
newlines: self.newlines,
tabs: self.tabs,
text: &self.text,
}
}
#[inline(always)]
pub fn slice(&self, range: Range<usize>) -> ChunkSlice<'_> {
self.as_slice().slice(range)
}
#[inline(always)]
pub fn chars(&self) -> u128 {
self.chars
}
}
#[derive(Clone, Copy, Debug)]
pub struct ChunkSlice<'a> {
chars: u128,
chars_utf16: u128,
newlines: u128,
tabs: u128,
text: &'a str,
}
impl Into<Chunk> for ChunkSlice<'_> {
fn into(self) -> Chunk {
Chunk {
chars: self.chars,
chars_utf16: self.chars_utf16,
newlines: self.newlines,
tabs: self.tabs,
text: self.text.try_into().unwrap(),
}
}
}
impl<'a> ChunkSlice<'a> {
#[inline(always)]
pub fn is_empty(&self) -> bool {
self.text.is_empty()
}
#[inline(always)]
pub fn is_char_boundary(self, offset: usize) -> bool {
self.text.is_char_boundary(offset)
}
#[inline(always)]
pub fn split_at(self, mid: usize) -> (ChunkSlice<'a>, ChunkSlice<'a>) {
if mid == MAX_BASE {
let left = self;
let right = ChunkSlice {
chars: 0,
chars_utf16: 0,
newlines: 0,
tabs: 0,
text: "",
};
(left, right)
} else {
let mask = (1u128 << mid) - 1;
let (left_text, right_text) = self.text.split_at(mid);
let left = ChunkSlice {
chars: self.chars & mask,
chars_utf16: self.chars_utf16 & mask,
newlines: self.newlines & mask,
tabs: self.tabs & mask,
text: left_text,
};
let right = ChunkSlice {
chars: self.chars >> mid,
chars_utf16: self.chars_utf16 >> mid,
newlines: self.newlines >> mid,
tabs: self.tabs >> mid,
text: right_text,
};
(left, right)
}
}
#[inline(always)]
pub fn slice(self, range: Range<usize>) -> Self {
let mask = if range.end == MAX_BASE {
u128::MAX
} else {
(1u128 << range.end) - 1
};
if range.start == MAX_BASE {
Self {
chars: 0,
chars_utf16: 0,
newlines: 0,
tabs: 0,
text: "",
}
} else {
Self {
chars: (self.chars & mask) >> range.start,
chars_utf16: (self.chars_utf16 & mask) >> range.start,
newlines: (self.newlines & mask) >> range.start,
tabs: (self.tabs & mask) >> range.start,
text: &self.text[range],
}
}
}
#[inline(always)]
pub fn text_summary(&self) -> TextSummary {
let mut chars = 0;
let (longest_row, longest_row_chars) = self.longest_row(&mut chars);
TextSummary {
len: self.len(),
chars,
len_utf16: self.len_utf16(),
lines: self.lines(),
first_line_chars: self.first_line_chars(),
last_line_chars: self.last_line_chars(),
last_line_len_utf16: self.last_line_len_utf16(),
longest_row,
longest_row_chars,
}
}
/// Get length in bytes
#[inline(always)]
pub fn len(&self) -> usize {
self.text.len()
}
/// Get length in UTF-16 code units
#[inline(always)]
pub fn len_utf16(&self) -> OffsetUtf16 {
OffsetUtf16(self.chars_utf16.count_ones() as usize)
}
/// Get point representing number of lines and length of last line
#[inline(always)]
pub fn lines(&self) -> Point {
let row = self.newlines.count_ones();
let column = self.newlines.leading_zeros() - (u128::BITS - self.text.len() as u32);
Point::new(row, column)
}
/// Get number of chars in first line
#[inline(always)]
pub fn first_line_chars(&self) -> u32 {
if self.newlines == 0 {
self.chars.count_ones()
} else {
let mask = (1u128 << self.newlines.trailing_zeros()) - 1;
(self.chars & mask).count_ones()
}
}
/// Get number of chars in last line
#[inline(always)]
pub fn last_line_chars(&self) -> u32 {
if self.newlines == 0 {
self.chars.count_ones()
} else {
let mask = !(u128::MAX >> self.newlines.leading_zeros());
(self.chars & mask).count_ones()
}
}
/// Get number of UTF-16 code units in last line
#[inline(always)]
pub fn last_line_len_utf16(&self) -> u32 {
if self.newlines == 0 {
self.chars_utf16.count_ones()
} else {
let mask = !(u128::MAX >> self.newlines.leading_zeros());
(self.chars_utf16 & mask).count_ones()
}
}
/// Get the longest row in the chunk and its length in characters.
/// Calculate the total number of characters in the chunk along the way.
#[inline(always)]
pub fn longest_row(&self, total_chars: &mut usize) -> (u32, u32) {
let mut chars = self.chars;
let mut newlines = self.newlines;
*total_chars = 0;
let mut row = 0;
let mut longest_row = 0;
let mut longest_row_chars = 0;
while newlines > 0 {
let newline_ix = newlines.trailing_zeros();
let row_chars = (chars & ((1 << newline_ix) - 1)).count_ones() as u8;
*total_chars += usize::from(row_chars);
if row_chars > longest_row_chars {
longest_row = row;
longest_row_chars = row_chars;
}
newlines >>= newline_ix;
newlines >>= 1;
chars >>= newline_ix;
chars >>= 1;
row += 1;
*total_chars += 1;
}
let row_chars = chars.count_ones() as u8;
*total_chars += usize::from(row_chars);
if row_chars > longest_row_chars {
(row, row_chars as u32)
} else {
(longest_row, longest_row_chars as u32)
}
}
#[inline(always)]
pub fn offset_to_point(&self, offset: usize) -> Point {
let mask = if offset == MAX_BASE {
u128::MAX
} else {
(1u128 << offset) - 1
};
let row = (self.newlines & mask).count_ones();
let newline_ix = u128::BITS - (self.newlines & mask).leading_zeros();
let column = (offset - newline_ix as usize) as u32;
Point::new(row, column)
}
#[inline(always)]
pub fn point_to_offset(&self, point: Point) -> usize {
if point.row > self.lines().row {
debug_panic!(
"point {:?} extends beyond rows for string {:?}",
point,
self.text
);
return self.len();
}
let row_offset_range = self.offset_range_for_row(point.row);
if point.column > row_offset_range.len() as u32 {
debug_panic!(
"point {:?} extends beyond row for string {:?}",
point,
self.text
);
row_offset_range.end
} else {
row_offset_range.start + point.column as usize
}
}
#[inline(always)]
pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
let mask = if offset == MAX_BASE {
u128::MAX
} else {
(1u128 << offset) - 1
};
OffsetUtf16((self.chars_utf16 & mask).count_ones() as usize)
}
#[inline(always)]
pub fn offset_utf16_to_offset(&self, target: OffsetUtf16) -> usize {
if target.0 == 0 {
0
} else {
let ix = nth_set_bit(self.chars_utf16, target.0) + 1;
if ix == MAX_BASE {
MAX_BASE
} else {
let utf8_additional_len = cmp::min(
(self.chars_utf16 >> ix).trailing_zeros() as usize,
self.text.len() - ix,
);
ix + utf8_additional_len
}
}
}
#[inline(always)]
pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
let mask = if offset == MAX_BASE {
u128::MAX
} else {
(1u128 << offset) - 1
};
let row = (self.newlines & mask).count_ones();
let newline_ix = u128::BITS - (self.newlines & mask).leading_zeros();
let column = if newline_ix as usize == MAX_BASE {
0
} else {
((self.chars_utf16 & mask) >> newline_ix).count_ones()
};
PointUtf16::new(row, column)
}
#[inline(always)]
pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
self.offset_to_point_utf16(self.point_to_offset(point))
}
#[inline(always)]
pub fn point_utf16_to_offset(&self, point: PointUtf16, clip: bool) -> usize {
let lines = self.lines();
if point.row > lines.row {
if !clip {
debug_panic!(
"point {:?} is beyond this chunk's extent {:?}",
point,
self.text
);
}
return self.len();
}
let row_offset_range = self.offset_range_for_row(point.row);
let line = self.slice(row_offset_range.clone());
if point.column > line.last_line_len_utf16() {
if !clip {
debug_panic!(
"point {:?} is beyond the end of the line in chunk {:?}",
point,
self.text
);
}
return line.len();
}
let mut offset = row_offset_range.start;
if point.column > 0 {
offset += line.offset_utf16_to_offset(OffsetUtf16(point.column as usize));
if !self.text.is_char_boundary(offset) {
offset -= 1;
while !self.text.is_char_boundary(offset) {
offset -= 1;
}
if !clip {
debug_panic!(
"point {:?} is within character in chunk {:?}",
point,
self.text,
);
}
}
}
offset
}
#[inline(always)]
pub fn unclipped_point_utf16_to_point(&self, point: Unclipped<PointUtf16>) -> Point {
let max_point = self.lines();
if point.0.row > max_point.row {
return max_point;
}
let row_offset_range = self.offset_range_for_row(point.0.row);
let line = self.slice(row_offset_range);
if point.0.column == 0 {
Point::new(point.0.row, 0)
} else if point.0.column >= line.len_utf16().0 as u32 {
Point::new(point.0.row, line.len() as u32)
} else {
let mut column = line.offset_utf16_to_offset(OffsetUtf16(point.0.column as usize));
while !line.text.is_char_boundary(column) {
column -= 1;
}
Point::new(point.0.row, column as u32)
}
}
#[inline(always)]
pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
let max_point = self.lines();
if point.row > max_point.row {
return max_point;
}
let line = self.slice(self.offset_range_for_row(point.row));
if point.column == 0 {
point
} else if point.column >= line.len() as u32 {
Point::new(point.row, line.len() as u32)
} else {
let mut column = point.column as usize;
let bytes = line.text.as_bytes();
if bytes[column - 1] < 128 && bytes[column] < 128 {
return Point::new(point.row, column as u32);
}
let mut grapheme_cursor = GraphemeCursor::new(column, bytes.len(), true);
loop {
if line.is_char_boundary(column)
&& grapheme_cursor.is_boundary(line.text, 0).unwrap_or(false)
{
break;
}
match bias {
Bias::Left => column -= 1,
Bias::Right => column += 1,
}
grapheme_cursor.set_cursor(column);
}
Point::new(point.row, column as u32)
}
}
#[inline(always)]
pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
let max_point = self.lines();
if point.0.row > max_point.row {
PointUtf16::new(max_point.row, self.last_line_len_utf16())
} else {
let line = self.slice(self.offset_range_for_row(point.0.row));
let column = line.clip_offset_utf16(OffsetUtf16(point.0.column as usize), bias);
PointUtf16::new(point.0.row, column.0 as u32)
}
}
#[inline(always)]
pub fn clip_offset_utf16(&self, target: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
if target == OffsetUtf16::default() {
OffsetUtf16::default()
} else if target >= self.len_utf16() {
self.len_utf16()
} else {
let mut offset = self.offset_utf16_to_offset(target);
while !self.text.is_char_boundary(offset) {
if bias == Bias::Left {
offset -= 1;
} else {
offset += 1;
}
}
self.offset_to_offset_utf16(offset)
}
}
#[inline(always)]
fn offset_range_for_row(&self, row: u32) -> Range<usize> {
let row_start = if row > 0 {
nth_set_bit(self.newlines, row as usize) + 1
} else {
0
};
let row_len = if row_start == MAX_BASE {
0
} else {
cmp::min(
(self.newlines >> row_start).trailing_zeros(),
(self.text.len() - row_start) as u32,
)
};
row_start..row_start + row_len as usize
}
#[inline(always)]
pub fn tabs(&self) -> Tabs {
Tabs {
tabs: self.tabs,
chars: self.chars,
}
}
}
pub struct Tabs {
tabs: u128,
chars: u128,
}
#[derive(Debug, PartialEq, Eq)]
pub struct TabPosition {
pub byte_offset: usize,
pub char_offset: usize,
}
impl Iterator for Tabs {
type Item = TabPosition;
fn next(&mut self) -> Option<Self::Item> {
if self.tabs == 0 {
return None;
}
let tab_offset = self.tabs.trailing_zeros() as usize;
let chars_mask = (1 << tab_offset) - 1;
let char_offset = (self.chars & chars_mask).count_ones() as usize;
// Since tabs are 1 byte the tab offset is the same as the byte offset
let position = TabPosition {
byte_offset: tab_offset,
char_offset,
};
// Remove the tab we've just seen
self.tabs ^= 1 << tab_offset;
Some(position)
}
}
/// Finds the n-th bit that is set to 1.
#[inline(always)]
fn nth_set_bit(v: u128, n: usize) -> usize {
let low = v as u64;
let high = (v >> 64) as u64;
let low_count = low.count_ones() as usize;
if n > low_count {
64 + nth_set_bit_u64(high, (n - low_count) as u64) as usize
} else {
nth_set_bit_u64(low, n as u64) as usize
}
}
#[inline(always)]
fn nth_set_bit_u64(v: u64, mut n: u64) -> u64 {
let v = v.reverse_bits();
let mut s: u64 = 64;
// Parallel bit count intermediates
let a = v - ((v >> 1) & (u64::MAX / 3));
let b = (a & (u64::MAX / 5)) + ((a >> 2) & (u64::MAX / 5));
let c = (b + (b >> 4)) & (u64::MAX / 0x11);
let d = (c + (c >> 8)) & (u64::MAX / 0x101);
// Branchless select
let t = (d >> 32) + (d >> 48);
s -= (t.wrapping_sub(n) & 256) >> 3;
n -= t & (t.wrapping_sub(n) >> 8);
let t = (d >> (s - 16)) & 0xff;
s -= (t.wrapping_sub(n) & 256) >> 4;
n -= t & (t.wrapping_sub(n) >> 8);
let t = (c >> (s - 8)) & 0xf;
s -= (t.wrapping_sub(n) & 256) >> 5;
n -= t & (t.wrapping_sub(n) >> 8);
let t = (b >> (s - 4)) & 0x7;
s -= (t.wrapping_sub(n) & 256) >> 6;
n -= t & (t.wrapping_sub(n) >> 8);
let t = (a >> (s - 2)) & 0x3;
s -= (t.wrapping_sub(n) & 256) >> 7;
n -= t & (t.wrapping_sub(n) >> 8);
let t = (v >> (s - 1)) & 0x1;
s -= (t.wrapping_sub(n) & 256) >> 8;
65 - s - 1
}
#[cfg(test)]
mod tests {
use super::*;
use rand::prelude::*;
use util::RandomCharIter;
#[gpui::test(iterations = 100)]
fn test_random_chunks(mut rng: StdRng) {
let chunk_len = rng.gen_range(0..=MAX_BASE);
let text = RandomCharIter::new(&mut rng)
.take(chunk_len)
.collect::<String>();
let mut ix = chunk_len;
while !text.is_char_boundary(ix) {
ix -= 1;
}
let text = &text[..ix];
log::info!("Chunk: {:?}", text);
let chunk = Chunk::new(text);
verify_chunk(chunk.as_slice(), text);
for _ in 0..10 {
let mut start = rng.gen_range(0..=chunk.text.len());
let mut end = rng.gen_range(start..=chunk.text.len());
while !chunk.text.is_char_boundary(start) {
start -= 1;
}
while !chunk.text.is_char_boundary(end) {
end -= 1;
}
let range = start..end;
log::info!("Range: {:?}", range);
let text_slice = &text[range.clone()];
let chunk_slice = chunk.slice(range);
verify_chunk(chunk_slice, text_slice);
}
}
#[gpui::test(iterations = 1000)]
fn test_nth_set_bit_random(mut rng: StdRng) {
let set_count = rng.gen_range(0..=128);
let mut set_bits = (0..128).choose_multiple(&mut rng, set_count);
set_bits.sort();
let mut n = 0;
for ix in set_bits.iter().copied() {
n |= 1 << ix;
}
for (mut ix, position) in set_bits.into_iter().enumerate() {
ix += 1;
assert_eq!(
nth_set_bit(n, ix),
position,
"nth_set_bit({:0128b}, {})",
n,
ix
);
}
}
fn verify_chunk(chunk: ChunkSlice<'_>, text: &str) {
let mut offset = 0;
let mut offset_utf16 = OffsetUtf16(0);
let mut point = Point::zero();
let mut point_utf16 = PointUtf16::zero();
log::info!("Verifying chunk {:?}", text);
assert_eq!(chunk.offset_to_point(0), Point::zero());
let mut expected_tab_positions = Vec::new();
for (char_offset, c) in text.chars().enumerate() {
let expected_point = chunk.offset_to_point(offset);
assert_eq!(point, expected_point, "mismatch at offset {}", offset);
assert_eq!(
chunk.point_to_offset(point),
offset,
"mismatch at point {:?}",
point
);
assert_eq!(
chunk.offset_to_offset_utf16(offset),
offset_utf16,
"mismatch at offset {}",
offset
);
assert_eq!(
chunk.offset_utf16_to_offset(offset_utf16),
offset,
"mismatch at offset_utf16 {:?}",
offset_utf16
);
assert_eq!(
chunk.point_to_point_utf16(point),
point_utf16,
"mismatch at point {:?}",
point
);
assert_eq!(
chunk.point_utf16_to_offset(point_utf16, false),
offset,
"mismatch at point_utf16 {:?}",
point_utf16
);
assert_eq!(
chunk.unclipped_point_utf16_to_point(Unclipped(point_utf16)),
point,
"mismatch for unclipped_point_utf16_to_point at {:?}",
point_utf16
);
assert_eq!(
chunk.clip_point(point, Bias::Left),
point,
"incorrect left clip at {:?}",
point
);
assert_eq!(
chunk.clip_point(point, Bias::Right),
point,
"incorrect right clip at {:?}",
point
);
for i in 1..c.len_utf8() {
let test_point = Point::new(point.row, point.column + i as u32);
assert_eq!(
chunk.clip_point(test_point, Bias::Left),
point,
"incorrect left clip within multi-byte char at {:?}",
test_point
);
assert_eq!(
chunk.clip_point(test_point, Bias::Right),
Point::new(point.row, point.column + c.len_utf8() as u32),
"incorrect right clip within multi-byte char at {:?}",
test_point
);
}
for i in 1..c.len_utf16() {
let test_point = Unclipped(PointUtf16::new(
point_utf16.row,
point_utf16.column + i as u32,
));
assert_eq!(
chunk.unclipped_point_utf16_to_point(test_point),
point,
"incorrect unclipped_point_utf16_to_point within multi-byte char at {:?}",
test_point
);
assert_eq!(
chunk.clip_point_utf16(test_point, Bias::Left),
point_utf16,
"incorrect left clip_point_utf16 within multi-byte char at {:?}",
test_point
);
assert_eq!(
chunk.clip_point_utf16(test_point, Bias::Right),
PointUtf16::new(point_utf16.row, point_utf16.column + c.len_utf16() as u32),
"incorrect right clip_point_utf16 within multi-byte char at {:?}",
test_point
);
let test_offset = OffsetUtf16(offset_utf16.0 + i);
assert_eq!(
chunk.clip_offset_utf16(test_offset, Bias::Left),
offset_utf16,
"incorrect left clip_offset_utf16 within multi-byte char at {:?}",
test_offset
);
assert_eq!(
chunk.clip_offset_utf16(test_offset, Bias::Right),
OffsetUtf16(offset_utf16.0 + c.len_utf16()),
"incorrect right clip_offset_utf16 within multi-byte char at {:?}",
test_offset
);
}
if c == '\n' {
point.row += 1;
point.column = 0;
point_utf16.row += 1;
point_utf16.column = 0;
} else {
point.column += c.len_utf8() as u32;
point_utf16.column += c.len_utf16() as u32;
}
if c == '\t' {
expected_tab_positions.push(TabPosition {
byte_offset: offset,
char_offset,
});
}
offset += c.len_utf8();
offset_utf16.0 += c.len_utf16();
}
let final_point = chunk.offset_to_point(offset);
assert_eq!(point, final_point, "mismatch at final offset {}", offset);
assert_eq!(
chunk.point_to_offset(point),
offset,
"mismatch at point {:?}",
point
);
assert_eq!(
chunk.offset_to_offset_utf16(offset),
offset_utf16,
"mismatch at offset {}",
offset
);
assert_eq!(
chunk.offset_utf16_to_offset(offset_utf16),
offset,
"mismatch at offset_utf16 {:?}",
offset_utf16
);
assert_eq!(
chunk.point_to_point_utf16(point),
point_utf16,
"mismatch at final point {:?}",
point
);
assert_eq!(
chunk.point_utf16_to_offset(point_utf16, false),
offset,
"mismatch at final point_utf16 {:?}",
point_utf16
);
assert_eq!(
chunk.unclipped_point_utf16_to_point(Unclipped(point_utf16)),
point,
"mismatch for unclipped_point_utf16_to_point at final point {:?}",
point_utf16
);
assert_eq!(
chunk.clip_point(point, Bias::Left),
point,
"incorrect left clip at final point {:?}",
point
);
assert_eq!(
chunk.clip_point(point, Bias::Right),
point,
"incorrect right clip at final point {:?}",
point
);
assert_eq!(
chunk.clip_point_utf16(Unclipped(point_utf16), Bias::Left),
point_utf16,
"incorrect left clip_point_utf16 at final point {:?}",
point_utf16
);
assert_eq!(
chunk.clip_point_utf16(Unclipped(point_utf16), Bias::Right),
point_utf16,
"incorrect right clip_point_utf16 at final point {:?}",
point_utf16
);
assert_eq!(
chunk.clip_offset_utf16(offset_utf16, Bias::Left),
offset_utf16,
"incorrect left clip_offset_utf16 at final offset {:?}",
offset_utf16
);
assert_eq!(
chunk.clip_offset_utf16(offset_utf16, Bias::Right),
offset_utf16,
"incorrect right clip_offset_utf16 at final offset {:?}",
offset_utf16
);
// Verify length methods
assert_eq!(chunk.len(), text.len());
assert_eq!(
chunk.len_utf16().0,
text.chars().map(|c| c.len_utf16()).sum::<usize>()
);
// Verify line counting
let lines = chunk.lines();
let mut newline_count = 0;
let mut last_line_len = 0;
for c in text.chars() {
if c == '\n' {
newline_count += 1;
last_line_len = 0;
} else {
last_line_len += c.len_utf8() as u32;
}
}
assert_eq!(lines, Point::new(newline_count, last_line_len));
// Verify first/last line chars
if !text.is_empty() {
let first_line = text.split('\n').next().unwrap();
assert_eq!(chunk.first_line_chars(), first_line.chars().count() as u32);
let last_line = text.split('\n').next_back().unwrap();
assert_eq!(chunk.last_line_chars(), last_line.chars().count() as u32);
assert_eq!(
chunk.last_line_len_utf16(),
last_line.chars().map(|c| c.len_utf16() as u32).sum::<u32>()
);
}
// Verify longest row
let (longest_row, longest_chars) = chunk.longest_row(&mut 0);
let mut max_chars = 0;
let mut current_row = 0;
let mut current_chars = 0;
let mut max_row = 0;
for c in text.chars() {
if c == '\n' {
if current_chars > max_chars {
max_chars = current_chars;
max_row = current_row;
}
current_row += 1;
current_chars = 0;
} else {
current_chars += 1;
}
}
if current_chars > max_chars {
max_chars = current_chars;
max_row = current_row;
}
assert_eq!((max_row, max_chars as u32), (longest_row, longest_chars));
assert_eq!(chunk.tabs().collect::<Vec<_>>(), expected_tab_positions);
}
}