Commit b529ed1e authored by Kenichi Handa's avatar Kenichi Handa
Browse files

(encode-coding-char): Fix for ASCII characters.

parent a509862b
......@@ -2805,29 +2805,32 @@ If there's no description string for VALUE, return nil."
(defun encode-coding-char (char coding-system)
"Encode CHAR by CODING-SYSTEM and return the resulting string.
If CODING-SYSTEM can't safely encode CHAR, return nil."
(let ((str1 (string-as-multibyte (string char)))
(str2 (string-as-multibyte (string char char)))
(let* ((str1 (string-as-multibyte (string char)))
(str2 (string-as-multibyte (string char char)))
(found (find-coding-systems-string str1))
enc1 enc2 i1 i2)
(when (memq (coding-system-base coding-system)
(find-coding-systems-string str1))
;; We must find the encoded string of CHAR. But, just encoding
;; CHAR will put extra control sequences (usually to designate
;; ASCII charset) at the tail if type of CODING is ISO 2022.
;; To exclude such tailing bytes, we at first encode one-char
;; string and two-char string, then check how many bytes at the
;; tail of both encoded strings are the same.
(setq enc1 (encode-coding-string str1 coding-system)
i1 (length enc1)
enc2 (encode-coding-string str2 coding-system)
i2 (length enc2))
(while (and (> i1 0) (= (aref enc1 (1- i1)) (aref enc2 (1- i2))))
(setq i1 (1- i1) i2 (1- i2)))
;; Now (substring enc1 i1) and (substring enc2 i2) are the same,
;; and they are the extra control sequences at the tail to
;; exclude.
(substring enc2 0 i2))))
(if (and (consp found)
(eq (car found) 'undecided))
str1
(when (memq (coding-system-base coding-system) found)
;; We must find the encoded string of CHAR. But, just encoding
;; CHAR will put extra control sequences (usually to designate
;; ASCII charset) at the tail if type of CODING is ISO 2022.
;; To exclude such tailing bytes, we at first encode one-char
;; string and two-char string, then check how many bytes at the
;; tail of both encoded strings are the same.
(setq enc1 (encode-coding-string str1 coding-system)
i1 (length enc1)
enc2 (encode-coding-string str2 coding-system)
i2 (length enc2))
(while (and (> i1 0) (= (aref enc1 (1- i1)) (aref enc2 (1- i2))))
(setq i1 (1- i1) i2 (1- i2)))
;; Now (substring enc1 i1) and (substring enc2 i2) are the same,
;; and they are the extra control sequences at the tail to
;; exclude.
(substring enc2 0 i2)))))
;; Backwards compatibility. These might be better with :init-value t,
;; but that breaks loadup.
......
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