94 lines
2.5 KiB
Go
94 lines
2.5 KiB
Go
// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
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package wcswidth
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import (
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"errors"
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"fmt"
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"kitty/tools/utils"
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)
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var _ = fmt.Print
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type truncate_error struct {
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pos, width int
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}
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func (self *truncate_error) Error() string {
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return fmt.Sprint("Truncation at:", self.pos, " with width:", self.width)
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}
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type truncate_iterator struct {
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w WCWidthIterator
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pos, limit int
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limit_exceeded_at *truncate_error
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}
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func (self *truncate_iterator) handle_csi(body []byte) error {
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self.pos += len(body) + 2
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return nil
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}
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func (self *truncate_iterator) handle_st_terminated_escape_code(body []byte) error {
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self.pos += len(body) + 4
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return nil
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}
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func create_truncate_iterator() *truncate_iterator {
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var ans truncate_iterator
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ans.w.parser.HandleRune = ans.handle_rune
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ans.w.parser.HandleCSI = ans.handle_csi
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ans.w.parser.HandleOSC = ans.handle_st_terminated_escape_code
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ans.w.parser.HandleAPC = ans.handle_st_terminated_escape_code
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ans.w.parser.HandleDCS = ans.handle_st_terminated_escape_code
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ans.w.parser.HandlePM = ans.handle_st_terminated_escape_code
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ans.w.parser.HandleSOS = ans.handle_st_terminated_escape_code
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return &ans
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}
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func (self *truncate_iterator) handle_rune(ch rune) error {
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width := self.w.current_width
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self.w.handle_rune(ch)
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if self.limit_exceeded_at != nil {
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if self.w.current_width <= self.limit { // emoji variation selectors can cause width to decrease
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return &truncate_error{pos: self.pos + len(string(ch)), width: self.w.current_width}
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}
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return self.limit_exceeded_at
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}
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if self.w.current_width > self.limit {
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self.limit_exceeded_at = &truncate_error{pos: self.pos, width: width}
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}
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self.pos += len(string(ch))
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return nil
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}
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func (self *truncate_iterator) parse(b []byte) (ans int, width int) {
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err := self.w.parser.Parse(b)
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var te *truncate_error
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if err != nil && errors.As(err, &te) {
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return te.pos, te.width
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}
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if self.limit_exceeded_at != nil {
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return self.limit_exceeded_at.pos, self.limit_exceeded_at.width
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}
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return len(b), self.w.current_width
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}
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func TruncateToVisualLengthWithWidth(text string, length int) (truncated string, width_of_truncated int) {
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if length < 1 {
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return text[:0], 0
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}
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t := create_truncate_iterator()
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t.limit = length
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t.limit_exceeded_at = nil
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t.w.current_width = 0
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truncate_point, width := t.parse(utils.UnsafeStringToBytes(text))
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return text[:truncate_point], width
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}
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func TruncateToVisualLength(text string, length int) string {
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ans, _ := TruncateToVisualLengthWithWidth(text, length)
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return ans
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}
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