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// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
package wcswidth
import (
"errors"
"fmt"
"strconv"
"github.com/kovidgoyal/kitty/tools/utils"
)
var _ = fmt.Print
type truncate_error struct {
pos, width int
}
func (self *truncate_error) Error() string {
return fmt.Sprint("Truncation at:", self.pos, " with width:", self.width)
}
type truncate_iterator struct {
w WCWidthIterator
pos, limit int
limit_exceeded_at *truncate_error
}
func (self *truncate_iterator) handle_csi(csi []byte) error {
if len(csi) > 1 && csi[len(csi)-1] == 'b' { // repeat previous char escape code
num_string := utils.UnsafeBytesToString(csi[:len(csi)-1])
n, err := strconv.Atoi(num_string)
if err == nil && n > 0 {
width_before_repeat := self.w.current_width
for ; n > 0; n-- {
self.w.handle_rune(self.w.prev_ch)
if self.w.current_width > self.limit {
return &truncate_error{pos: self.pos, width: width_before_repeat}
}
}
}
}
self.pos += len(csi) + 2
return nil
}
func (self *truncate_iterator) handle_st_terminated_escape_code(body []byte) error {
self.pos += len(body) + 4
return nil
}
func create_truncate_iterator() *truncate_iterator {
var ans truncate_iterator
ans.w.parser.HandleRune = ans.handle_rune
ans.w.parser.HandleCSI = ans.handle_csi
ans.w.parser.HandleOSC = ans.handle_st_terminated_escape_code
ans.w.parser.HandleAPC = ans.handle_st_terminated_escape_code
ans.w.parser.HandleDCS = ans.handle_st_terminated_escape_code
ans.w.parser.HandlePM = ans.handle_st_terminated_escape_code
ans.w.parser.HandleSOS = ans.handle_st_terminated_escape_code
return &ans
}
func (self *truncate_iterator) handle_rune(ch rune) error {
width := self.w.current_width
self.w.handle_rune(ch)
if self.limit_exceeded_at != nil {
if self.w.current_width <= self.limit { // emoji variation selectors can cause width to decrease
return &truncate_error{pos: self.pos + len(string(ch)), width: self.w.current_width}
}
return self.limit_exceeded_at
}
if self.w.current_width > self.limit {
self.limit_exceeded_at = &truncate_error{pos: self.pos, width: width}
}
self.pos += len(string(ch))
return nil
}
func (self *truncate_iterator) parse(b []byte) (ans int, width int) {
err := self.w.parser.Parse(b)
var te *truncate_error
if err != nil && errors.As(err, &te) {
return te.pos, te.width
}
if self.limit_exceeded_at != nil {
return self.limit_exceeded_at.pos, self.limit_exceeded_at.width
}
return len(b), self.w.current_width
}
func TruncateToVisualLengthWithWidth(text string, length int) (truncated string, width_of_truncated int) {
if length < 1 {
return text[:0], 0
}
t := create_truncate_iterator()
t.limit = length
t.limit_exceeded_at = nil
t.w.current_width = 0
truncate_point, width := t.parse(utils.UnsafeStringToBytes(text))
return text[:truncate_point], width
}
func TruncateToVisualLength(text string, length int) string {
ans, _ := TruncateToVisualLengthWithWidth(text, length)
return ans
}
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