Use the more efficient cell iterator api for single char horizontal cursor movement as well

This commit is contained in:
Kovid Goyal 2022-10-23 20:58:32 +05:30
parent a008c627e3
commit 19bf07abd9
No known key found for this signature in database
GPG Key ID: 06BC317B515ACE7C
2 changed files with 13 additions and 43 deletions

View File

@ -34,7 +34,7 @@ func (self *Readline) text_after_cursor_pos() string {
buf.Grow(1024) buf.Grow(1024)
for i, line := range self.lines { for i, line := range self.lines {
if i == self.cursor.Y { if i == self.cursor.Y {
buf.WriteString(line[self.cursor.X:]) buf.WriteString(line[utils.Min(len(line), self.cursor.X):])
buf.WriteString("\n") buf.WriteString("\n")
} else if i > self.cursor.Y { } else if i > self.cursor.Y {
buf.WriteString(line) buf.WriteString(line)
@ -94,38 +94,27 @@ func (self *Readline) add_text(text string) {
self.lines = new_lines self.lines = new_lines
} }
func (self *Readline) move_cursor_left(amt uint, traverse_line_breaks bool) uint { func (self *Readline) move_cursor_left(amt uint, traverse_line_breaks bool) (amt_moved uint) {
var amt_moved uint for amt_moved < amt {
for ; amt > 0; amt -= 1 {
if self.cursor.X == 0 { if self.cursor.X == 0 {
if !traverse_line_breaks || self.cursor.Y == 0 { if !traverse_line_breaks || self.cursor.Y == 0 {
return amt_moved return amt_moved
} }
self.cursor.Y -= 1 self.cursor.Y -= 1
self.cursor.X = len(self.lines[self.cursor.Y]) self.cursor.X = len(self.lines[self.cursor.Y])
amt_moved += 1 amt_moved++
continue continue
} }
// This is an extremely inefficient algorithm but it does not matter since
// lines are not large.
line := self.lines[self.cursor.Y] line := self.lines[self.cursor.Y]
runes := []rune(line[:self.cursor.X]) for ci := wcswidth.NewCellIterator(line[:self.cursor.X]).GotoEnd(); amt_moved < amt && ci.Backward(); amt_moved++ {
orig_width := wcswidth.Stringwidth(line[:self.cursor.X]) self.cursor.X -= len(ci.Current())
current_width := orig_width
for current_width == orig_width && len(runes) > 0 {
runes = runes[:len(runes)-1]
s := string(runes)
current_width = wcswidth.Stringwidth(s)
} }
self.cursor.X = len(string(runes))
amt_moved += 1
} }
return amt_moved return amt_moved
} }
func (self *Readline) move_cursor_right(amt uint, traverse_line_breaks bool) uint { func (self *Readline) move_cursor_right(amt uint, traverse_line_breaks bool) (amt_moved uint) {
var amt_moved uint for amt_moved < amt {
for ; amt > 0; amt -= 1 {
line := self.lines[self.cursor.Y] line := self.lines[self.cursor.Y]
if self.cursor.X >= len(line) { if self.cursor.X >= len(line) {
if !traverse_line_breaks || self.cursor.Y == len(self.lines)-1 { if !traverse_line_breaks || self.cursor.Y == len(self.lines)-1 {
@ -133,32 +122,13 @@ func (self *Readline) move_cursor_right(amt uint, traverse_line_breaks bool) uin
} }
self.cursor.Y += 1 self.cursor.Y += 1
self.cursor.X = 0 self.cursor.X = 0
amt_moved += 1 amt_moved++
continue continue
} }
// This is an extremely inefficient algorithm but it does not matter since
// lines are not large. for ci := wcswidth.NewCellIterator(line[self.cursor.X:]); amt_moved < amt && ci.Forward(); amt_moved++ {
before_runes := []rune(line[:self.cursor.X]) self.cursor.X += len(ci.Current())
after_runes := []rune(line[self.cursor.X:])
orig_width := wcswidth.Stringwidth(line[:self.cursor.X])
current_width := orig_width
for current_width == orig_width && len(after_runes) > 0 {
before_runes = append(before_runes, after_runes[0])
current_width = wcswidth.Stringwidth(string(before_runes))
after_runes = after_runes[1:]
} }
// soak up any more runes that dont affect width
for len(after_runes) > 0 {
q := append(before_runes, after_runes[0])
w := wcswidth.Stringwidth(string(q))
if w != current_width {
break
}
after_runes = after_runes[1:]
before_runes = q
}
self.cursor.X = len(string(before_runes))
amt_moved += 1
} }
return amt_moved return amt_moved
} }

View File

@ -158,7 +158,7 @@ func TestCursorMovement(t *testing.T) {
rl.cursor.X = 0 rl.cursor.X = 0
actual := rl.move_cursor_right(amt, traverse_line_breaks) actual := rl.move_cursor_right(amt, traverse_line_breaks)
if actual != moved_amt { if actual != moved_amt {
t.Fatalf("Failed to move cursor by %#v\nactual != expected: %#v != %#v", amt, actual, moved_amt) t.Fatalf("Failed to move cursor by %d\nactual != expected: %d != %d", amt, actual, moved_amt)
} }
} }
dt("one\ntwo", func(rl *Readline) { dt("one\ntwo", func(rl *Readline) {