use std::ops::{Drop, Index, IndexMut, RangeFrom, RangeFull};
use crate::{
buffer::{BufferContent, CharDisplayDistances},
buffer_position::{BufferPosition, BufferRange},
};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Cursor {
pub anchor: BufferPosition,
pub position: BufferPosition,
}
impl Cursor {
pub const fn zero() -> Self {
Self {
anchor: BufferPosition::zero(),
position: BufferPosition::zero(),
}
}
pub fn to_range(&self) -> BufferRange {
BufferRange::between(self.anchor, self.position)
}
pub fn insert(&mut self, range: BufferRange) {
self.anchor = self.anchor.insert(range);
self.position = self.position.insert(range);
}
pub fn delete(&mut self, range: BufferRange) {
self.anchor = self.anchor.delete(range);
self.position = self.position.delete(range);
}
}
#[derive(Clone)]
pub struct CursorCollection {
cursors: Box<[Cursor; Self::capacity()]>,
len: u8,
saved_display_distances: Box<[u32; Self::capacity()]>,
saved_display_distances_len: u8,
main_cursor_index: u8,
}
impl CursorCollection {
pub const fn capacity() -> usize {
u8::MAX as _
}
pub fn new() -> Self {
Self {
cursors: Box::new([Cursor::zero(); Self::capacity()]),
len: 1,
saved_display_distances: Box::new([0; Self::capacity()]),
saved_display_distances_len: 0,
main_cursor_index: 0,
}
}
pub fn main_cursor_index(&self) -> usize {
self.main_cursor_index as _
}
pub fn main_cursor(&self) -> &Cursor {
&self.cursors[self.main_cursor_index as usize]
}
pub fn mut_guard(&mut self) -> CursorCollectionMutGuard {
CursorCollectionMutGuard {
inner: self,
clear_display_distances: true,
}
}
fn sort_and_merge(&mut self) {
let main_cursor = self.cursors[self.main_cursor_index as usize];
self.cursors[..self.len as usize].sort_unstable_by_key(|c| c.to_range().from);
self.main_cursor_index = self.cursors[..self.len as usize]
.binary_search_by_key(&main_cursor.position, |c| c.position)
.unwrap_or(0) as _;
let mut i = 0;
while i < self.len {
let mut range = self.cursors[i as usize].to_range();
for j in ((i + 1)..self.len).rev() {
let other_range = self.cursors[j as usize].to_range();
if range.from <= other_range.from && other_range.from <= range.to {
range.to = range.to.max(other_range.to);
self.cursors
.copy_within((j + 1) as usize..self.len as usize, j as _);
self.len -= 1;
if j <= self.main_cursor_index {
self.main_cursor_index -= 1;
}
}
}
let cursor = &mut self.cursors[i as usize];
*cursor = if cursor.anchor <= cursor.position {
Cursor {
anchor: range.from,
position: range.to,
}
} else {
Cursor {
anchor: range.to,
position: range.from,
}
};
i += 1;
}
}
}
impl Index<usize> for CursorCollection {
type Output = Cursor;
fn index(&self, index: usize) -> &Self::Output {
&self.cursors[index as usize]
}
}
impl Index<RangeFull> for CursorCollection {
type Output = [Cursor];
fn index(&self, _: RangeFull) -> &Self::Output {
&self.cursors[..self.len as usize]
}
}
impl Index<RangeFrom<usize>> for CursorCollection {
type Output = [Cursor];
fn index(&self, index: RangeFrom<usize>) -> &Self::Output {
&self.cursors[index.start..self.len as _]
}
}
pub struct CursorCollectionMutGuard<'a> {
inner: &'a mut CursorCollection,
clear_display_distances: bool,
}
impl<'a> CursorCollectionMutGuard<'a> {
pub fn clear(&mut self) {
self.inner.len = 0;
}
pub fn add(&mut self, cursor: Cursor) {
if let Some(len) = self.inner.len.checked_add(1) {
self.inner.cursors[self.inner.len as usize] = cursor;
self.inner.main_cursor_index = self.inner.len;
self.inner.len = len;
}
}
pub fn save_display_distances(&mut self, buffer: &BufferContent, tab_size: u8) {
self.clear_display_distances = false;
if self.inner.saved_display_distances_len == 0 {
for c in &self.inner.cursors[..self.inner.len as usize] {
let line = &buffer.lines()[c.position.line_index as usize].as_str()
[..c.position.column_byte_index as usize];
let distance = CharDisplayDistances::new(line, tab_size)
.last()
.map(|d| d.distance)
.unwrap_or(0);
self.inner.saved_display_distances
[self.inner.saved_display_distances_len as usize] = distance as _;
self.inner.saved_display_distances_len += 1;
}
}
}
pub fn get_saved_display_distance(&self, index: usize) -> Option<u32> {
if index < self.inner.saved_display_distances_len as usize {
Some(self.inner.saved_display_distances[index])
} else {
None
}
}
pub fn set_main_cursor_index(&mut self, index: usize) {
self.inner.main_cursor_index = index.min(CursorCollection::capacity()) as u8;
}
pub fn main_cursor(&mut self) -> &mut Cursor {
&mut self.inner.cursors[self.inner.main_cursor_index as usize]
}
}
impl<'a> Index<usize> for CursorCollectionMutGuard<'a> {
type Output = Cursor;
fn index(&self, index: usize) -> &Self::Output {
&self.inner.cursors[index as usize]
}
}
impl<'a> Index<RangeFull> for CursorCollectionMutGuard<'a> {
type Output = [Cursor];
fn index(&self, _: RangeFull) -> &Self::Output {
&self.inner.cursors[..self.inner.len as usize]
}
}
impl<'a> Index<RangeFrom<usize>> for CursorCollectionMutGuard<'a> {
type Output = [Cursor];
fn index(&self, index: RangeFrom<usize>) -> &Self::Output {
&self.inner.cursors[index.start..self.inner.len as _]
}
}
impl<'a> IndexMut<usize> for CursorCollectionMutGuard<'a> {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
&mut self.inner.cursors[index as usize]
}
}
impl<'a> IndexMut<RangeFull> for CursorCollectionMutGuard<'a> {
fn index_mut(&mut self, _: RangeFull) -> &mut Self::Output {
&mut self.inner.cursors[..self.inner.len as usize]
}
}
impl<'a> IndexMut<RangeFrom<usize>> for CursorCollectionMutGuard<'a> {
fn index_mut(&mut self, index: RangeFrom<usize>) -> &mut Self::Output {
&mut self.inner.cursors[index.start..self.inner.len as _]
}
}
impl<'a> Drop for CursorCollectionMutGuard<'a> {
fn drop(&mut self) {
if self.inner.len == 0 {
self.inner.cursors[0] = Cursor::zero();
self.inner.len = 1;
self.inner.main_cursor_index = 0;
}
self.inner.sort_and_merge();
if self.clear_display_distances {
self.inner.saved_display_distances_len = 0;
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn merge_cursor() {
let mut cursors = CursorCollection::new();
assert_eq!(1, cursors[..].len());
let main_cursor = *cursors.main_cursor();
cursors.mut_guard().add(main_cursor);
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::zero(), cursor.position);
assert_eq!(BufferPosition::zero(), cursor.anchor);
assert!(cursors.next().is_none());
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(2, 3);
cursors_mut[0].position = cursors_mut[0].anchor;
drop(cursors_mut);
assert_eq!(1, cursors[..].len());
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 2),
position: BufferPosition::line_col(2, 4),
});
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor);
assert_eq!(BufferPosition::line_col(2, 4), cursor.position);
assert!(cursors.next().is_none());
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(2, 2);
cursors_mut[0].position = BufferPosition::line_col(2, 4);
drop(cursors_mut);
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 2),
position: BufferPosition::line_col(2, 2),
});
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor);
assert_eq!(BufferPosition::line_col(2, 4), cursor.position);
assert!(cursors.next().is_none());
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(2, 2);
cursors_mut[0].position = BufferPosition::line_col(2, 3);
drop(cursors_mut);
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 4),
position: BufferPosition::line_col(2, 3),
});
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor);
assert_eq!(BufferPosition::line_col(2, 4), cursor.position);
assert!(cursors.next().is_none());
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(2, 4);
cursors_mut[0].position = BufferPosition::line_col(2, 3);
drop(cursors_mut);
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 3),
position: BufferPosition::line_col(2, 2),
});
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(2, 4), cursor.anchor);
assert_eq!(BufferPosition::line_col(2, 2), cursor.position);
assert!(cursors.next().is_none());
}
#[test]
fn no_merge_cursor() {
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(1, 0);
cursors_mut[0].position = BufferPosition::line_col(1, 0);
drop(cursors_mut);
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 0),
position: BufferPosition::line_col(2, 0),
});
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(1, 0), cursor.anchor);
assert_eq!(BufferPosition::line_col(1, 0), cursor.position);
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(2, 0), cursor.anchor);
assert_eq!(BufferPosition::line_col(2, 0), cursor.position);
assert!(cursors.next().is_none());
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(3, 2);
cursors_mut[0].position = BufferPosition::line_col(3, 2);
drop(cursors_mut);
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 2),
position: BufferPosition::line_col(2, 2),
});
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(2, 2), cursor.anchor);
assert_eq!(BufferPosition::line_col(2, 2), cursor.position);
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(3, 2), cursor.anchor);
assert_eq!(BufferPosition::line_col(3, 2), cursor.position);
assert!(cursors.next().is_none());
}
#[test]
fn move_and_merge_cursors() {
let mut cursors = CursorCollection::new();
let mut cursors_mut = cursors.mut_guard();
cursors_mut[0].anchor = BufferPosition::line_col(0, 0);
cursors_mut[0].position = BufferPosition::line_col(0, 0);
drop(cursors_mut);
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(1, 0),
position: BufferPosition::line_col(1, 0),
});
cursors.mut_guard().add(Cursor {
anchor: BufferPosition::line_col(2, 0),
position: BufferPosition::line_col(2, 0),
});
assert_eq!(3, cursors[..].len());
let mut cursors_mut = cursors.mut_guard();
for c in &mut cursors_mut[..] {
if c.position.line_index > 0 {
c.position.line_index -= 1;
}
c.anchor = c.position;
}
drop(cursors_mut);
let cursor = cursors.main_cursor();
assert_eq!(BufferPosition::line_col(1, 0), cursor.anchor);
assert_eq!(BufferPosition::line_col(1, 0), cursor.position);
let mut cursors = cursors[..].iter();
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(0, 0), cursor.anchor);
assert_eq!(BufferPosition::line_col(0, 0), cursor.position);
let cursor = cursors.next().unwrap();
assert_eq!(BufferPosition::line_col(1, 0), cursor.anchor);
assert_eq!(BufferPosition::line_col(1, 0), cursor.position);
assert!(cursors.next().is_none());
}
}