bendns' repos / helix
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'helix-stdx/src/rope.rs')
-rw-r--r--helix-stdx/src/rope.rs60
1 files changed, 60 insertions, 0 deletions
diff --git a/helix-stdx/src/rope.rs b/helix-stdx/src/rope.rs
index 78eb6629..e4dedd18 100644
--- a/helix-stdx/src/rope.rs
+++ b/helix-stdx/src/rope.rs
@@ -6,6 +6,8 @@ use regex_cursor::Input as RegexInput;
use ropey::{ChunkCursor, RopeSlice};
use unicode_segmentation::{GraphemeCursor, GraphemeIncomplete};
+pub const LINE_TYPE: ropey::LineType = ropey::LineType::LF_CR;
+
pub trait RopeSliceExt<'a>: Sized {
fn ends_with(self, text: &str) -> bool;
fn starts_with(self, text: &str) -> bool;
@@ -39,6 +41,10 @@ pub trait RopeSliceExt<'a>: Sized {
/// assert_eq!(text.floor_grapheme_boundary(2), 2);
/// ```
fn floor_grapheme_boundary(self, byte_idx: usize) -> usize;
+ fn prev_grapheme_boundary(self, byte_idx: usize) -> usize {
+ self.nth_prev_grapheme_boundary(byte_idx, 1)
+ }
+ fn nth_prev_grapheme_boundary(self, byte_idx: usize, n: usize) -> usize;
/// Finds the closest byte index not exceeding `byte_idx` which lies on a grapheme cluster
/// boundary.
///
@@ -60,6 +66,10 @@ pub trait RopeSliceExt<'a>: Sized {
/// assert_eq!(text.ceil_grapheme_boundary(2), 2);
/// ```
fn ceil_grapheme_boundary(self, byte_idx: usize) -> usize;
+ fn next_grapheme_boundary(self, byte_idx: usize) -> usize {
+ self.nth_next_grapheme_boundary(byte_idx, 1)
+ }
+ fn nth_next_grapheme_boundary(self, byte_idx: usize, n: usize) -> usize;
/// Checks whether the `byte_idx` lies on a grapheme cluster boundary.
///
/// # Example
@@ -185,6 +195,31 @@ impl<'a> RopeSliceExt<'a> for RopeSlice<'a> {
}
}
+ fn nth_prev_grapheme_boundary(self, mut byte_idx: usize, n: usize) -> usize {
+ byte_idx = self.floor_char_boundary(byte_idx);
+
+ let mut chunk_cursor = self.chunk_cursor_at(byte_idx);
+ let mut cursor = GraphemeCursor::new(byte_idx, self.len(), true);
+ for _ in 0..n {
+ loop {
+ match cursor.prev_boundary(chunk_cursor.chunk(), chunk_cursor.byte_offset()) {
+ Ok(None) => return 0,
+ Ok(Some(boundary)) => {
+ byte_idx = boundary;
+ break;
+ }
+ Err(GraphemeIncomplete::PrevChunk) => assert!(chunk_cursor.prev()),
+ Err(GraphemeIncomplete::PreContext(n)) => {
+ let ctx_chunk = self.chunk(n - 1).0;
+ cursor.provide_context(ctx_chunk, n - ctx_chunk.len());
+ }
+ _ => unreachable!(),
+ }
+ }
+ }
+ byte_idx
+ }
+
fn ceil_grapheme_boundary(self, mut byte_idx: usize) -> usize {
if byte_idx >= self.len() {
return self.len();
@@ -212,6 +247,31 @@ impl<'a> RopeSliceExt<'a> for RopeSlice<'a> {
}
}
+ fn nth_next_grapheme_boundary(self, mut byte_idx: usize, n: usize) -> usize {
+ byte_idx = self.ceil_char_boundary(byte_idx);
+
+ let mut chunk_cursor = self.chunk_cursor_at(byte_idx);
+ let mut cursor = GraphemeCursor::new(byte_idx, self.len(), true);
+ for _ in 0..n {
+ loop {
+ match cursor.prev_boundary(chunk_cursor.chunk(), chunk_cursor.byte_offset()) {
+ Ok(None) => return 0,
+ Ok(Some(boundary)) => {
+ byte_idx = boundary;
+ break;
+ }
+ Err(GraphemeIncomplete::NextChunk) => assert!(chunk_cursor.next()),
+ Err(GraphemeIncomplete::PreContext(n)) => {
+ let ctx_chunk = self.chunk(n - 1).0;
+ cursor.provide_context(ctx_chunk, n - ctx_chunk.len());
+ }
+ _ => unreachable!(),
+ }
+ }
+ }
+ byte_idx
+ }
+
fn is_grapheme_boundary(self, byte_idx: usize) -> bool {
// The byte must lie on a character boundary to lie on a grapheme cluster boundary.
if !self.is_char_boundary(byte_idx) {