diff options
Diffstat (limited to 'helix-core')
| -rw-r--r-- | helix-core/src/graphemes.rs | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/helix-core/src/graphemes.rs b/helix-core/src/graphemes.rs index 2e6a925f..e2f7c3f3 100644 --- a/helix-core/src/graphemes.rs +++ b/helix-core/src/graphemes.rs @@ -121,6 +121,30 @@ pub fn next_grapheme_boundary(slice: RopeSlice, char_idx: usize) -> usize { nth_next_grapheme_boundary(slice, char_idx, 1) } +/// Returns the passed char index if it's already a grapheme boundary, +/// or the next grapheme boundary char index if not. +pub fn ensure_grapheme_boundary(slice: RopeSlice, char_idx: usize) -> usize { + if char_idx == 0 { + 0 + } else { + next_grapheme_boundary(slice, char_idx - 1) + } +} + +/// Returns the passed byte index if it's already a grapheme boundary, +/// or the next grapheme boundary byte index if not. +pub fn ensure_grapheme_boundary_byte(slice: RopeSlice, byte_idx: usize) -> usize { + // TODO: we can avoid the byte/char conversions entirely + // if we also make byte versions of the other functions. + let char_idx = slice.byte_to_char(byte_idx); + let fixed_char_idx = ensure_grapheme_boundary(slice, char_idx); + if fixed_char_idx == char_idx { + byte_idx + } else { + slice.char_to_byte(fixed_char_idx) + } +} + /// Returns whether the given char position is a grapheme boundary. pub fn is_grapheme_boundary(slice: RopeSlice, char_idx: usize) -> bool { // Bounds check |