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use std::borrow::Cow;
use crate::{
chars::char_is_line_ending,
graphemes::{ensure_grapheme_boundary_prev, grapheme_width, RopeGraphemes},
line_ending::line_end_char_index,
RopeSlice,
};
/// Represents a single point in a text buffer. Zero indexed.
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub struct Position {
pub row: usize,
pub col: usize,
}
impl Position {
pub const fn new(row: usize, col: usize) -> Self {
Self { row, col }
}
pub const fn is_zero(self) -> bool {
self.row == 0 && self.col == 0
}
// TODO: generalize
pub fn traverse(self, text: &crate::Tendril) -> Self {
let Self { mut row, mut col } = self;
// TODO: there should be a better way here
let mut chars = text.chars().peekable();
while let Some(ch) = chars.next() {
if char_is_line_ending(ch) && !(ch == '\r' && chars.peek() == Some(&'\n')) {
row += 1;
col = 0;
} else {
col += 1;
}
}
Self { row, col }
}
}
impl From<(usize, usize)> for Position {
fn from(tuple: (usize, usize)) -> Self {
Self {
row: tuple.0,
col: tuple.1,
}
}
}
impl From<Position> for tree_sitter::Point {
fn from(pos: Position) -> Self {
Self::new(pos.row, pos.col)
}
}
/// Convert a character index to (line, column) coordinates.
///
/// TODO: this should be split into two methods: one for visual
/// row/column, and one for "objective" row/column (possibly with
/// the column specified in `char`s). The former would be used
/// for cursor movement, and the latter would be used for e.g. the
/// row:column display in the status line.
pub fn coords_at_pos(text: RopeSlice, pos: usize) -> Position {
let line = text.char_to_line(pos);
let line_start = text.line_to_char(line);
let pos = ensure_grapheme_boundary_prev(text, pos);
let col = RopeGraphemes::new(text.slice(line_start..pos))
.map(|g| {
let g: Cow<str> = g.into();
grapheme_width(&g)
})
.sum();
Position::new(line, col)
}
/// Convert (line, column) coordinates to a character index.
///
/// `is_1_width` specifies whether the position should be treated
/// as a block cursor or not. This effects how line-ends are handled.
/// `false` corresponds to properly round-tripping with `coords_at_pos()`,
/// whereas `true` will ensure that block cursors don't jump off the
/// end of the line.
pub fn pos_at_coords(text: RopeSlice, coords: Position, is_1_width: bool) -> usize {
let Position { row, col } = coords;
let line_start = text.line_to_char(row);
let line_end = if is_1_width {
line_end_char_index(&text, row)
} else {
text.line_to_char((row + 1).min(text.len_lines()))
};
let mut prev_col = 0;
let mut col_char_offset = 0;
for g in RopeGraphemes::new(text.slice(line_start..line_end)) {
let g: Cow<str> = g.into();
let next_col = prev_col + grapheme_width(&g);
if next_col > col {
break;
}
prev_col = next_col;
col_char_offset += g.chars().count();
}
line_start + col_char_offset
}
#[cfg(test)]
mod test {
use super::*;
use crate::Rope;
#[test]
fn test_ordering() {
// (0, 5) is less than (1, 0)
assert!(Position::new(0, 5) < Position::new(1, 0));
}
#[test]
fn test_coords_at_pos() {
let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
let slice = text.slice(..);
assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
assert_eq!(coords_at_pos(slice, 5), (0, 5).into()); // position on \n
assert_eq!(coords_at_pos(slice, 6), (1, 0).into()); // position on w
assert_eq!(coords_at_pos(slice, 7), (1, 1).into()); // position on o
assert_eq!(coords_at_pos(slice, 10), (1, 4).into()); // position on d
// Test with wide characters.
let text = Rope::from("今日はいい\n");
let slice = text.slice(..);
assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
assert_eq!(coords_at_pos(slice, 1), (0, 2).into());
assert_eq!(coords_at_pos(slice, 2), (0, 4).into());
assert_eq!(coords_at_pos(slice, 3), (0, 6).into());
assert_eq!(coords_at_pos(slice, 4), (0, 8).into());
assert_eq!(coords_at_pos(slice, 5), (0, 10).into());
assert_eq!(coords_at_pos(slice, 6), (1, 0).into());
// test with grapheme clusters
let text = Rope::from("a̐éö̲\r\n");
let slice = text.slice(..);
assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
assert_eq!(coords_at_pos(slice, 2), (0, 1).into());
assert_eq!(coords_at_pos(slice, 4), (0, 2).into());
assert_eq!(coords_at_pos(slice, 7), (0, 3).into());
assert_eq!(coords_at_pos(slice, 9), (1, 0).into());
let text = Rope::from("किमपि\n");
let slice = text.slice(..);
assert_eq!(coords_at_pos(slice, 0), (0, 0).into());
assert_eq!(coords_at_pos(slice, 2), (0, 2).into());
assert_eq!(coords_at_pos(slice, 3), (0, 3).into());
assert_eq!(coords_at_pos(slice, 5), (0, 5).into());
assert_eq!(coords_at_pos(slice, 6), (1, 0).into());
}
#[test]
fn test_pos_at_coords() {
let text = Rope::from("ḧëḷḷö\nẅöṛḷḋ");
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into(), false), 0);
assert_eq!(pos_at_coords(slice, (0, 5).into(), false), 5); // position on \n
assert_eq!(pos_at_coords(slice, (0, 6).into(), false), 6); // position after \n
assert_eq!(pos_at_coords(slice, (0, 6).into(), true), 5); // position after \n
assert_eq!(pos_at_coords(slice, (1, 0).into(), false), 6); // position on w
assert_eq!(pos_at_coords(slice, (1, 1).into(), false), 7); // position on o
assert_eq!(pos_at_coords(slice, (1, 4).into(), false), 10); // position on d
// Test with wide characters.
let text = Rope::from("今日はいい\n");
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into(), false), 0);
assert_eq!(pos_at_coords(slice, (0, 1).into(), false), 0);
assert_eq!(pos_at_coords(slice, (0, 2).into(), false), 1);
assert_eq!(pos_at_coords(slice, (0, 3).into(), false), 1);
assert_eq!(pos_at_coords(slice, (0, 4).into(), false), 2);
assert_eq!(pos_at_coords(slice, (0, 6).into(), false), 3);
assert_eq!(pos_at_coords(slice, (0, 8).into(), false), 4);
assert_eq!(pos_at_coords(slice, (0, 10).into(), false), 5);
assert_eq!(pos_at_coords(slice, (0, 11).into(), false), 6);
assert_eq!(pos_at_coords(slice, (0, 11).into(), true), 5);
assert_eq!(pos_at_coords(slice, (1, 0).into(), false), 6);
// test with grapheme clusters
let text = Rope::from("a̐éö̲\r\n");
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into(), false), 0);
assert_eq!(pos_at_coords(slice, (0, 1).into(), false), 2);
assert_eq!(pos_at_coords(slice, (0, 2).into(), false), 4);
assert_eq!(pos_at_coords(slice, (0, 3).into(), false), 7); // \r\n is one char here
assert_eq!(pos_at_coords(slice, (0, 4).into(), false), 9);
assert_eq!(pos_at_coords(slice, (0, 4).into(), true), 7);
assert_eq!(pos_at_coords(slice, (1, 0).into(), false), 9);
let text = Rope::from("किमपि");
// 2 - 1 - 2 codepoints
// TODO: delete handling as per https://news.ycombinator.com/item?id=20058454
let slice = text.slice(..);
assert_eq!(pos_at_coords(slice, (0, 0).into(), false), 0);
assert_eq!(pos_at_coords(slice, (0, 1).into(), false), 0);
assert_eq!(pos_at_coords(slice, (0, 2).into(), false), 2);
assert_eq!(pos_at_coords(slice, (0, 3).into(), false), 3);
assert_eq!(pos_at_coords(slice, (0, 4).into(), false), 3);
assert_eq!(pos_at_coords(slice, (0, 5).into(), false), 5); // eol
}
}
|
