(utf-translate-cjk-charsets): New
authorKenichi Handa <handa@m17n.org>
Sat, 12 Jun 2004 02:10:37 +0000 (02:10 +0000)
committerKenichi Handa <handa@m17n.org>
Sat, 12 Jun 2004 02:10:37 +0000 (02:10 +0000)
variable.
(utf-translate-cjk-unicode-range): New variable.
(utf-translate-cjk-load-tables): New function.
(utf-lookup-subst-table-for-decode): New function.
(utf-lookup-subst-table-for-encode): New function.
(utf-translate-cjk-mode): Init-value changed to t.  Don't load
tables here.  Update safe-charsets of utf-* coding systems.
(ccl-mule-utf-untrans): New CCL.
(ccl-decode-mule-utf-8): Call ccl-mule-utf-untrans.  Use `repeat'
at end of each branch.
(ccl-mule-utf-8-encode-untrans): New CCL.
(ccl-encode-mule-utf-8): Call ccl-mule-utf-8-encode-untrans.
(ccl-untranslated-to-ucs): Handle 2-byte encoding.  Set r1 to the
length of encoding.  Don't return r0.
(utf-8-compose): New arg hash-table.  Handle 2-byte encoding.
(utf-8-post-read-conversion): Narrow to region properly.  If
utf-translate-cjk-mode is on, load tables if necessary.  Call
utf-8-compose with hash-table arg if necessary.  Call
XXX-compose-region instead of XXX-post-read-convesion.
(utf-8-pre-write-conversion): New function.
(mule-utf-8): Include CJK charsets in safe-charsets if
utf-translate-cjk-mode is on.  Add pre-write-conversion.

lisp/international/utf-8.el

index d4dd7b6..e324d0c 100644 (file)
@@ -190,9 +190,102 @@ Setting this variable outside customize has no effect."
   :type 'boolean
   :group 'mule)
 
+
+(defconst utf-translate-cjk-charsets '(chinese-gb2312
+                                      chinese-big5-1 chinese-big5-2
+                                      japanese-jisx0208 japanese-jisx0212
+                                      korean-ksc5601)
+  "List of charsets supported by `utf-translate-cjk-mode'.")
+
+(defconst utf-translate-cjk-unicode-range
+  '((#x2e80 . #xd7a3)
+    (#xff00 . #xffef))
+  "List of Unicode code ranges supported by `utf-translate-cjk-mode'.")
+
+;; Return non-nil if CODE-POINT is in `utf-translate-cjk-unicode-range'.
+(defsubst utf-translate-cjk-substitutable-p (code-point)
+  (let ((tail utf-translate-cjk-unicode-range)
+       elt)
+    (while tail
+      (setq elt (car tail) tail (cdr tail))
+      (if (and (>= code-point (car elt)) (<= code-point (cdr elt)))
+         (setq tail nil)
+       (setq elt nil)))
+    elt))
+
+(defvar utf-translate-cjk-lang-env nil
+  "Language environment in which tables for `utf-translate-cjk-mode' is loaded.
+The value nil means that the tables are not yet loaded.")
+
+(defun utf-translate-cjk-load-tables ()
+  "Load tables for `utf-translate-cjk-mode'."
+  ;; Fixme: Allow the use of the CJK charsets to be
+  ;; customized by reordering and possible omission.
+  (let ((redefined (< (hash-table-size ucs-mule-cjk-to-unicode) 43000)))
+    (if redefined
+       ;; Redefine them with realistic initial sizes and a
+       ;; smallish rehash size to avoid wasting significant
+       ;; space after they're built.
+       (setq ucs-mule-cjk-to-unicode
+             (make-hash-table :test 'eq :size 43000 :rehash-size 1000)
+             ucs-unicode-to-mule-cjk
+             (make-hash-table :test 'eq :size 21500 :rehash-size 1000)))
+
+    ;; Load the files explicitly, to avoid having to keep
+    ;; around the large tables they contain (as well as the
+    ;; ones which get built).
+    (cond ((string= "Korean" current-language-environment)
+          (load "subst-jis")
+          (load "subst-big5")
+          (load "subst-gb2312")
+          (load "subst-ksc"))
+         ((string= "Chinese-BIG5" current-language-environment)
+          (load "subst-jis")
+          (load "subst-ksc")
+          (load "subst-gb2312")
+          (load "subst-big5"))
+         ((string= "Chinese-GB" current-language-environment)
+          (load "subst-jis")
+          (load "subst-ksc")
+          (load "subst-big5")
+          (load "subst-gb2312"))
+         (t
+          (load "subst-ksc")
+          (load "subst-gb2312")
+          (load "subst-big5")
+          (load "subst-jis")))   ; jis covers as much as big5, gb2312
+
+    (when redefined
+      (define-translation-hash-table 'utf-subst-table-for-decode
+       ucs-unicode-to-mule-cjk)
+      (define-translation-hash-table 'utf-subst-table-for-encode
+       ucs-mule-cjk-to-unicode)
+      (set-char-table-extra-slot (get 'utf-translation-table-for-encode
+                                     'translation-table)
+                                1 ucs-mule-cjk-to-unicode))
+
+    (setq utf-translate-cjk-lang-env current-language-environment)))
+
+(defun utf-lookup-subst-table-for-decode (code-point)
+  (if (and utf-translate-cjk-mode
+          (not utf-translate-cjk-lang-env)
+          (utf-translate-cjk-substitutable-p code-point))
+      (utf-translate-cjk-load-tables))
+  (gethash code-point
+          (get 'utf-subst-table-for-decode 'translation-hash-table)))
+  
+
+(defun utf-lookup-subst-table-for-encode (char)
+  (if (and utf-translate-cjk-mode
+          (not utf-translate-cjk-lang-env)
+          (memq (char-charset char) utf-translate-cjk-charsets))
+      (utf-translate-cjk-load-tables))
+  (gethash char
+          (get 'utf-subst-table-for-encode 'translation-hash-table)))
+  
 (define-minor-mode utf-translate-cjk-mode
   "Whether the UTF based coding systems should decode/encode CJK characters.
-Enabling this loads tables which allow the coding systems mule-utf-8,
+Enabling this allows the coding systems mule-utf-8,
 mule-utf-16le and mule-utf-16be to encode characters in the charsets
 `korean-ksc5601', `chinese-gb2312', `chinese-big5-1',
 `chinese-big5-2', `japanese-jisx0208' and `japanese-jisx0212', and to
@@ -203,49 +296,16 @@ according to the language environment in effect when this option is
 turned on: ksc5601 for Korean, gb2312 for Chinese-GB, big5 for
 Chinese-Big5 and jisx for other environments.
 
-The tables are large (over 40000 entries), so this option is not the
-default.  Also, installing them may be rather slow."
-  :init-value nil
+This option is on by default.  If you are not interested in CJK
+characters and want to avoid some overhead on encoding/decoding
+by the above coding systems, you can customize this option to nil."
+  :init-value t
   :version "21.4"
   :type 'boolean
-  :set-after '(current-language-environment)
   :group 'mule
   :global t
   (if utf-translate-cjk-mode
-      ;; Fixme: Allow the use of the CJK charsets to be
-      ;; customized by reordering and possible omission.
       (progn
-       ;; Redefine them with realistic initial sizes and a
-       ;; smallish rehash size to avoid wasting significant
-       ;; space after they're built.
-       (setq ucs-mule-cjk-to-unicode
-             (make-hash-table :test 'eq :size 43000 :rehash-size 1000)
-             ucs-unicode-to-mule-cjk
-             (make-hash-table :test 'eq :size 21500 :rehash-size 1000))
-       ;; Load the files explicitly, to avoid having to keep
-       ;; around the large tables they contain (as well as the
-       ;; ones which get built).
-       (cond
-        ((string= "Korean" current-language-environment)
-         (load "subst-jis")
-         (load "subst-big5")
-         (load "subst-gb2312")
-         (load "subst-ksc"))
-        ((string= "Chinese-BIG5" current-language-environment)
-         (load "subst-jis")
-         (load "subst-ksc")
-         (load "subst-gb2312")
-         (load "subst-big5"))
-        ((string= "Chinese-GB" current-language-environment)
-         (load "subst-jis")
-         (load "subst-ksc")
-         (load "subst-big5")
-         (load "subst-gb2312"))
-        (t
-         (load "subst-ksc")
-         (load "subst-gb2312")
-         (load "subst-big5")
-         (load "subst-jis")))    ; jis covers as much as big5, gb2312
        (define-translation-hash-table 'utf-subst-table-for-decode
          ucs-unicode-to-mule-cjk)
        (define-translation-hash-table 'utf-subst-table-for-encode
@@ -259,7 +319,58 @@ default.  Also, installing them may be rather slow."
       (make-hash-table :test 'eq))
     (set-char-table-extra-slot (get 'utf-translation-table-for-encode
                                    'translation-table)
-                              1 nil)))
+                              1 nil))
+
+  ;; Update safe-chars of mule-utf-* coding systems.
+  (dolist (elt (coding-system-list t))
+    (if (string-match "^mule-utf" (symbol-name elt))
+       (let ((safe-charsets (coding-system-get elt 'safe-charsets))
+             (safe-chars (coding-system-get elt 'safe-chars))
+             (need-update nil))
+         (dolist (charset utf-translate-cjk-charsets)
+           (unless (eq utf-translate-cjk-mode (memq charset safe-charsets))
+             (setq safe-charsets
+                   (if utf-translate-cjk-mode
+                       (cons charset safe-charsets)
+                     (delq charset safe-charsets))
+                   need-update t)
+             (aset safe-chars (make-char charset) utf-translate-cjk-mode)))
+         (when need-update
+           (coding-system-put elt 'safe-charsets safe-charsets)
+           (define-coding-system-internal elt))))))
+
+(define-ccl-program ccl-mule-utf-untrans
+  ;; R0 is an untranslatable Unicode code-point (U+3500..U+DFFF or
+  ;; U+10000..U+10FFFF) or an invaid byte (#x00..#xFF).  Write
+  ;; eight-bit-control/graphic sequence (2 to 4 chars) representing
+  ;; UTF-8 sequence of r0.  Registers r4, r5, r6 are modified.
+  ;;
+  ;; This is a subrountine because we assume that this is called very
+  ;; rarely (so we don't have to worry about the overhead of the
+  ;; call).
+  `(0
+    ((r5 = ,(charset-id 'eight-bit-control))
+     (r6 = ,(charset-id 'eight-bit-graphic))
+     (if (r0 < #x100)
+        ((r4 = ((r0 >> 6) | #xC0))
+         (write-multibyte-character r6 r4))
+       ((if (r0 < #x10000)
+           ((r4 = ((r0 >> 12) | #xE0))
+            (write-multibyte-character r6 r4))
+         ((r4 = ((r0 >> 18) | #xF0))
+          (write-multibyte-character r6 r4)
+          (r4 = (((r0 >> 12) & #x3F) | #x80))
+          (if (r4 < #xA0)
+              (write-multibyte-character r5 r4)
+            (write-multibyte-character r6 r4))))
+       (r4 = (((r0 >> 6) & #x3F) | #x80))
+       (if (r4 < #xA0)
+           (write-multibyte-character r5 r4)
+         (write-multibyte-character r6 r4))))
+     (r4 = ((r0 & #x3F) | #x80))
+     (if (r4 < #xA0)
+        (write-multibyte-character r5 r4)
+       (write-multibyte-character r6 r4)))))
 
 (define-ccl-program ccl-decode-mule-utf-8
   ;;
@@ -278,260 +389,206 @@ default.  Also, installing them may be rather slow."
   ;;        (>= 8000)       |                |
   ;; mule-unicode-2500-33ff |       3        |       4
   ;; mule-unicode-e000-ffff |       3        |       4
+  ;; -----------------------+----------------+---------------
+  ;;      invalid byte      |       1        |       2
   ;;
   ;; Thus magnification factor is two.
   ;;
   `(2
-    ((r5 = ,(charset-id 'eight-bit-control))
-     (r6 = ,(charset-id 'eight-bit-graphic))
+    ((r0 = -1)
      (loop
-      (r0 = -1)
-      (read r0)
-
-      ;; 1byte encoding, i.e., ascii
+      (if (r0 < 0)
+         (read r0))
       (if (r0 < #x80)
-         ((write r0))
-       (if (r0 < #xc0)             ; continuation byte (invalid here)
-           ((if (r0 < #xa0)
-                (write-multibyte-character r5 r0)
-              (write-multibyte-character r6 r0)))
-         ;; 2 byte encoding 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
-         (if (r0 < #xe0)
-             ((r1 = -1)
-              (read r1)
-
-              (if ((r1 & #b11000000) != #b10000000)
-                  ;; Invalid 2-byte sequence
-                  ((if (r0 < #xa0)
-                       (write-multibyte-character r5 r0)
-                     (write-multibyte-character r6 r0))
-                   (if (r1 < #x80)
-                       (write r1)
-                     (if (r1 < #xa0)
-                         (write-multibyte-character r5 r1)
-                       (write-multibyte-character r6 r1))))
-
-                ((r3 = r0)        ; save in case of overlong sequence
-                 (r2 = r1)
-                 (r0 &= #x1f)
-                 (r0 <<= 6)
-                 (r1 &= #x3f)
-                 (r1 += r0)
-                 ;; Now r1 holds scalar value
-
-                 (if (r1 < 128)        ; `overlong sequence'
-                     ((if (r3 < #xa0)
-                          (write-multibyte-character r5 r3)
-                        (write-multibyte-character r6 r3))
-                      (if (r2 < #x80)
-                          (write r2)
-                        (if (r2 < #xa0)
-                            (write-multibyte-character r5 r2)
-                          (write-multibyte-character r6 r2))))
-
-                   ;; eight-bit-control
-                   (if (r1 < 160)
-                       ((write-multibyte-character r5 r1))
-
-                     ;; latin-iso8859-1
-                     (if (r1 < 256)
-                         ((r0 = ,(charset-id 'latin-iso8859-1))
-                          (r1 -= 128)
-                          (write-multibyte-character r0 r1))
-
-                       ;; mule-unicode-0100-24ff (< 0800)
-                       ((r0 = ,(charset-id 'mule-unicode-0100-24ff))
-                        (r1 -= #x0100)
-                        (r2 = (((r1 / 96) + 32) << 7))
-                        (r1 %= 96)
-                        (r1 += (r2 + 32))
-                        (translate-character
-                         utf-translation-table-for-decode r0 r1)
-                        (write-multibyte-character r0 r1))))))))
-
-           ;; 3byte encoding
-           ;; zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
-           (if (r0 < #xf0)
-               ((r1 = -1)
-                (r2 = -1)
-                (read r1 r2)
-
-                ;; This is set to 1 if the encoding is invalid.
-                (r4 = 0)
-
-                (r3 = (r1 & #b11000000))
-                (r3 |= ((r2 >> 2) & #b00110000))
-                (if (r3 != #b10100000)
-                    (r4 = 1)
-                  ((r3 = ((r0 & #x0f) << 12))
-                   (r3 += ((r1 & #x3f) << 6))
-                   (r3 += (r2 & #x3f))
-                   (if (r3 < #x0800)
-                       (r4 = 1))))
-
-                (if (r4 != 0)
-                    ;; Invalid 3-byte sequence
-                    ((if (r0 < #xa0)
-                         (write-multibyte-character r5 r0)
-                       (write-multibyte-character r6 r0))
-                     (if (r1 < #x80)
-                         (write r1)
-                       (if (r1 < #xa0)
-                           (write-multibyte-character r5 r1)
-                         (write-multibyte-character r6 r1)))
-                     (if (r2 < #x80)
-                         (write r2)
-                       (if (r2 < #xa0)
-                           (write-multibyte-character r5 r2)
-                         (write-multibyte-character r6 r2))))
-
-                  ;; mule-unicode-0100-24ff (>= 0800)
-                  ((if (r3 < #x2500)
-                       ((r0 = ,(charset-id 'mule-unicode-0100-24ff))
-                        (r3 -= #x0100)
-                        (r3 //= 96)
-                        (r1 = (r7 + 32))
-                        (r1 += ((r3 + 32) << 7))
-                        (translate-character
-                         utf-translation-table-for-decode r0 r1)
-                        (write-multibyte-character r0 r1))
-
-                     ;; mule-unicode-2500-33ff
-                     (if (r3 < #x3400)
-                         ((r4 = r3)    ; don't zap r3
-                          (lookup-integer utf-subst-table-for-decode r4 r5)
-                          (if r7
-                              ;; got a translation
-                              ((write-multibyte-character r4 r5)
-                               ;; Zapped through register starvation.
-                               (r5 = ,(charset-id 'eight-bit-control)))
-                            ((r0 = ,(charset-id 'mule-unicode-2500-33ff))
-                             (r3 -= #x2500)
-                             (r3 //= 96)
-                             (r1 = (r7 + 32))
-                             (r1 += ((r3 + 32) << 7))
-                             (write-multibyte-character r0 r1))))
-
-                       ;; U+3400 .. U+D7FF
-                       ;; Try to convert to CJK chars, else keep
-                       ;; them as eight-bit-{control|graphic}.
-                       (if (r3 < #xd800)
-                           ((r4 = r3)  ; don't zap r3
-                            (lookup-integer utf-subst-table-for-decode r4 r5)
-                            (if r7
-                                ;; got a translation
-                                ((write-multibyte-character r4 r5)
-                                 ;; Zapped through register starvation.
-                                 (r5 = ,(charset-id 'eight-bit-control)))
-                              ;; #xe0 <= r0 < #xf0, so r0 is eight-bit-graphic
-                              ((r3 = r6)
-                               (write-multibyte-character r3 r0)
-                               (if (r1 < #xa0)
-                                   (r3 = r5))
-                               (write-multibyte-character r3 r1)
-                               (if (r2 < #xa0)
-                                   (r3 = r5)
-                                 (r3 = r6))
-                               (write-multibyte-character r3 r2))))
-
-                         ;; Surrogates, U+D800 .. U+DFFF
-                         (if (r3 < #xe000)
-                             ((r3 = r6)
-                              (write-multibyte-character r3 r0) ; eight-bit-graphic
-                              (if (r1 < #xa0)
-                                  (r3 = r5))
-                              (write-multibyte-character r3 r1)
-                              (if (r2 < #xa0)
-                                  (r3 = r5)
-                                (r3 = r6))
-                              (write-multibyte-character r3 r2))
-
-                           ;; mule-unicode-e000-ffff
-                           ;; Fixme: fffe and ffff are invalid.
-                           ((r4 = r3)  ; don't zap r3
-                            (lookup-integer utf-subst-table-for-decode r4 r5)
-                            (if r7
-                                ;; got a translation
-                                ((write-multibyte-character r4 r5)
-                                 ;; Zapped through register starvation.
-                                 (r5 = ,(charset-id 'eight-bit-control)))
-                              ((r0 = ,(charset-id 'mule-unicode-e000-ffff))
-                               (r3 -= #xe000)
-                               (r3 //= 96)
-                               (r1 = (r7 + 32))
-                               (r1 += ((r3 + 32) << 7))
-                               (write-multibyte-character r0 r1)))))))))))
-
-             (if (r0 < #xfe)
-                 ;; 4byte encoding
-                 ;; keep those bytes as eight-bit-{control|graphic}
-                 ;; Fixme: allow lookup in utf-subst-table-for-decode.
-                 ((r1 = -1)
-                  (r2 = -1)
-                  (r3 = -1)
-                  (read r1 r2 r3)
-                  ;; r0 > #xf0, thus eight-bit-graphic
-                  (write-multibyte-character r6 r0)
-                  (if (r1 < #xa0)
-                      (if (r1 < #x80)  ; invalid byte
-                          (write r1)
-                        (write-multibyte-character r5 r1))
-                    (write-multibyte-character r6 r1))
-                  (if (r2 < #xa0)
-                      (if (r2 < #x80)  ; invalid byte
-                          (write r2)
-                        (write-multibyte-character r5 r2))
-                    (write-multibyte-character r6 r2))
-                  (if (r3 < #xa0)
-                      (if (r3 < #x80)  ; invalid byte
-                          (write r3)
-                        (write-multibyte-character r5 r3))
-                    (write-multibyte-character r6 r3))
-                  (if (r0 >= #xf8)     ; 5- or 6-byte encoding
-                      ((r0 = -1)
-                       (read r0)
-                       (if (r0 < #xa0)
-                           (if (r0 < #x80) ; invalid byte
-                               (write r0)
-                             (write-multibyte-character r5 r0))
-                         (write-multibyte-character r6 r0))
-                       (if (r0 >= #xfc) ; 6-byte
-                           ((r0 = -1)
-                            (read r0)
-                            (if (r0 < #xa0)
-                                (if (r0 < #x80) ; invalid byte
-                                    (write r0)
-                                  (write-multibyte-character r5 r0))
-                              (write-multibyte-character r6 r0)))))))
-               ;; else invalid byte >= #xfe
-               (write-multibyte-character r6 r0))))))
+         ;; 1-byte encoding, i.e., ascii
+         ((write r0)
+          (r0 = -1)
+          (repeat)))
+      (if (r0 < #xc0)              ; continuation byte (invalid here)
+         ((call ccl-mule-utf-untrans)
+          (r0 = -1)
+          (repeat)))
+
+      ;; Read the 2nd byte.
+      (r1 = -1)
+      (read r1)
+      (if ((r1 & #b11000000) != #b10000000) ; Invalid 2nd byte
+         ((call ccl-mule-utf-untrans)
+          ;; Handle it in the next loop.
+          (r0 = r1)
+          (repeat)))
+
+      (if (r0 < #xe0)
+         ;; 2-byte encoding 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
+         ((r2 = ((r0 & #x1F) << 6))
+          (r2 |= (r1 & #x3F))
+          ;; Now r2 holds scalar value
+
+          (if (r2 < 128)       ; `overlong sequence'
+              ((call ccl-mule-utf-untrans)
+               (r0 = r1)
+               (call ccl-mule-utf-untrans)
+               (r0 = -1)
+               (repeat)))
+
+          (r1 = r2)
+          (if (r1 < 160)
+              ;; eight-bit-control
+              (r0 = ,(charset-id 'eight-bit-control))
+            (if (r1 < 256)
+                ;; latin-iso8859-1
+                ((r0 = ,(charset-id 'latin-iso8859-1))
+                 (r1 -= 128))
+              ;; mule-unicode-0100-24ff (< 0800)
+              ((r0 = ,(charset-id 'mule-unicode-0100-24ff))
+               (r1 -= #x0100)
+               (r2 = (((r1 / 96) + 32) << 7))
+               (r1 %= 96)
+               (r1 += (r2 + 32))
+               (translate-character
+                utf-translation-table-for-decode r0 r1))))
+          (write-multibyte-character r0 r1)
+          (r0 = -1)
+          (repeat)))
+
+      ;; Read the 3rd bytes.
+      (r2 = -1)
+      (read r2)
+      (if ((r2 & #b11000000) != #b10000000) ; Invalid 3rd byte
+         ((call ccl-mule-utf-untrans)
+          (r0 = r1)
+          (call ccl-mule-utf-untrans)
+          ;; Handle it in the next loop.
+          (r0 = r2)
+          (repeat)))
+
+      (if (r0 < #xF0)
+         ;; 3byte encoding
+         ;; zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
+         ((r3 = ((r0 & #xF) << 12))
+          (r3 |= ((r1 & #x3F) << 6))
+          (r3 |= (r2 & #x3F))
+
+          (if (r3 < #x800)             ; `overlong sequence'
+              ((call ccl-mule-utf-untrans)
+               (r0 = r1)
+               (call ccl-mule-utf-untrans)
+               (r0 = r2)
+               (call ccl-mule-utf-untrans)
+               (r0 = -1)
+               (repeat)))
+
+          (if (r3 < #x2500)
+              ;; mule-unicode-0100-24ff (>= 0800)
+              ((r0 = ,(charset-id 'mule-unicode-0100-24ff))
+               (r3 -= #x0100)
+               (r3 //= 96)
+               (r1 = (r7 + 32))
+               (r1 += ((r3 + 32) << 7))
+               (translate-character
+                utf-translation-table-for-decode r0 r1)
+               (write-multibyte-character r0 r1)
+               (r0 = -1)
+               (repeat)))
+
+          (if (r3 < #x3400)
+              ;; mule-unicode-2500-33ff
+              ((r0 = r3)               ; don't zap r3
+               (lookup-integer utf-subst-table-for-decode r0 r1)
+               (if (r7 == 0)
+                   ((r0 = ,(charset-id 'mule-unicode-2500-33ff))
+                    (r3 -= #x2500)
+                    (r3 //= 96)
+                    (r1 = (r7 + 32))
+                    (r1 += ((r3 + 32) << 7))))
+               (write-multibyte-character r0 r1)
+               (r0 = -1)
+               (repeat)))
+
+          (if (r3 < #xE000)
+              ;; Try to convert to CJK chars, else
+              ;; keep them as eight-bit-{control|graphic}.
+              ((r0 = r3)
+               (lookup-integer utf-subst-table-for-decode r3 r1)
+               (if r7
+                   ;; got a translation
+                   (write-multibyte-character r3 r1)
+                 (call ccl-mule-utf-untrans))
+               (r0 = -1)
+               (repeat)))
+
+          ;; mule-unicode-e000-ffff
+          ;; Fixme: fffe and ffff are invalid.
+          (r0 = r3)            ; don't zap r3
+          (lookup-integer utf-subst-table-for-decode r0 r1)
+          (if (r7 == 0)
+              ((r0 = ,(charset-id 'mule-unicode-e000-ffff))
+               (r3 -= #xe000)
+               (r3 //= 96)
+               (r1 = (r7 + 32))
+               (r1 += ((r3 + 32) << 7))))
+          (write-multibyte-character r0 r1)
+          (r0 = -1)
+          (repeat)))
+
+      ;; Read the 4th bytes.
+      (r3 = -1)
+      (read r3)
+      (if ((r3 & #b11000000) != #b10000000) ; Invalid 4th byte
+         ((call ccl-mule-utf-untrans)
+          (r0 = r1)
+          (call ccl-mule-utf-untrans)
+          ;; Handle it in the next loop.
+          (r0 = r3)
+          (repeat)))
+
+      (if (r3 < #xF8)
+         ;; 4-byte encoding:
+         ;; wwwzzzzzzyyyyyyxxxxxx = 11110www 10zzzzzz 10yyyyyy 10xxxxxx
+         ;; keep those bytes as eight-bit-{control|graphic}
+         ;; Fixme: allow lookup in utf-subst-table-for-decode.
+         ((r4 = ((r0 & #x7) << 18))
+          (r4 |= ((r1 & #x3F) << 12))
+          (r4 |= ((r2 & #x3F) << 6))
+          (r4 |= (r3 & #x3F))
+
+          (if (r4 < #x10000)           ; `overlong sequence'
+              ((call ccl-mule-utf-untrans)
+               (r0 = r1)
+               (call ccl-mule-utf-untrans)
+               (r0 = r2)
+               (call ccl-mule-utf-untrans)
+               (r0 = r3)
+               (call ccl-mule-utf-untrans))
+            ((r0 = r4)
+             (call ccl-mule-utf-untrans)))
+          (r0 = -1)
+          (repeat)))
+
+      ;; Unsupported sequence.
+      (call ccl-mule-utf-untrans)
+      (r0 = r1)
+      (call ccl-mule-utf-untrans)
+      (r0 = r2)
+      (call ccl-mule-utf-untrans)
+      (r0 = r3)
+      (call ccl-mule-utf-untrans)
+      (r0 = -1)
       (repeat)))
 
     ;; At EOF...
     (if (r0 >= 0)
-       ((if (r0 < #x80)
-            (write r0)
-          (if (r0 < #xa0)
-              (write-multibyte-character r5 r0)
-            ((write-multibyte-character r6 r0))))
+       ;; r0 >= #x80
+       ((call ccl-mule-utf-untrans)
         (if (r1 >= 0)
-            ((if (r1 < #x80)
-                 (write r1)
-               (if (r1 < #xa0)
-                   (write-multibyte-character r5 r1)
-                 ((write-multibyte-character r6 r1))))
+            ((r0 = r1)
+             (call ccl-mule-utf-untrans)
              (if (r2 >= 0)
-                 ((if (r2 < #x80)
-                      (write r2)
-                    (if (r2 < #xa0)
-                        (write-multibyte-character r5 r2)
-                      ((write-multibyte-character r6 r2))))
+                 ((r0 = r2)
+                  (call ccl-mule-utf-untrans)
                   (if (r3 >= 0)
-                      (if (r3 < #x80)
-                          (write r3)
-                        (if (r3 < #xa0)
-                            (write-multibyte-character r5 r3)
-                          ((write-multibyte-character r6 r3))))))))))))
+                      ((r0 = r3)
+                       (call ccl-mule-utf-untrans))))))))))
 
   "CCL program to decode UTF-8.
 Basic decoding is done into the charsets ascii, latin-iso8859-1 and
@@ -540,164 +597,206 @@ mule-unicode-*, but see also `utf-fragmentation-table' and
 Encodings of un-representable Unicode characters are decoded asis into
 eight-bit-control and eight-bit-graphic characters.")
 
+(define-ccl-program ccl-mule-utf-8-encode-untrans
+  ;; UTF-8 decoder generates an UTF-8 sequence represented by a
+  ;; sequence eight-bit-control/graphic chars for an untranslatable
+  ;; character and an invalid byte.
+  ;; 
+  ;; This CCL parses that sequence (the first byte is already in r1),
+  ;; writes out the original bytes of that sequence, and sets r5 to
+  ;; -1.
+  ;;
+  ;; If the eight-bit-control/graphic sequence is shorter than what r1
+  ;; suggests, it sets r5 and r6 to the last character read that
+  ;; should be handled by the next loop of a caller.
+  ;;
+  ;; Note: For UTF-8 validation, we only check if a character is
+  ;; eight-bit-control/graphic or not.  It may result in incorrect
+  ;; handling of random binary data, but such a data can't be encoded
+  ;; by UTF-8 anyway.  At least, UTF-8 decoders doesn't generate such
+  ;; a sequence even if a source contains invalid byte-sequence.
+  `(0
+    (;; Read the 2nd byte.
+     (read-multibyte-character r5 r6)
+     (r0 = (r5 != ,(charset-id 'eight-bit-control)))
+     (if ((r5 != ,(charset-id 'eight-bit-graphic)) & r0)
+        ((write r1)                    ; invalid UTF-8 
+         (r1 = -1)
+         (end)))
+
+     (if (r1 <= #xC3)
+        ;; 2-byte sequence for an originally invalid byte.
+        ((r6 &= #x3F)
+         (r6 |= ((r1 & #x1F) << 6))
+         (write r6)
+         (r5 = -1)
+         (end)))
+
+     (write r1 r6)
+     (r2 = r1)
+     (r1 = -1)
+     ;; Read the 3rd byte.
+     (read-multibyte-character r5 r6)
+     (r0 = (r5 != ,(charset-id 'eight-bit-control)))          
+     (if ((r5 != ,(charset-id 'eight-bit-graphic)) & r0)
+        (end))                         ; invalid UTF-8
+     (write r6)
+     (if (r2 < #xF0)
+        ;; 3-byte sequence for an untranslated character.
+        ((r5 = -1)
+         (end)))
+     ;; Read the 4th byte.
+     (read-multibyte-character r5 r6)
+     (r0 = (r5 != ,(charset-id 'eight-bit-control)))          
+     (if ((r5 != ,(charset-id 'eight-bit-graphic)) & r0)
+        (end))                 ; invalid UTF-8
+     ;; 4-byte sequence for an untranslated character.
+     (write r6)
+     (r5 = -1)
+     (end))
+
+    ;; At EOF...
+    ((r5 = -1)
+     (if (r1 >= 0)
+        (write r1)))))
+
 (define-ccl-program ccl-encode-mule-utf-8
   `(1
     ((r5 = -1)
      (loop
       (if (r5 < 0)
-         ((r1 = -1)
-          (read-multibyte-character r0 r1)
-          (translate-character utf-translation-table-for-encode r0 r1))
-       (;; We have already done read-multibyte-character.
-        (r0 = r5)
+         (read-multibyte-character r0 r1)
+       ;; Pre-read character is in r5 (charset-ID) and r6 (code-point).
+       ((r0 = r5)
         (r1 = r6)
         (r5 = -1)))
+      (translate-character utf-translation-table-for-encode r0 r1)
 
       (if (r0 == ,(charset-id 'ascii))
-         (write r1)
-
-       (if (r0 == ,(charset-id 'latin-iso8859-1))
-           ;; r1          scalar                  utf-8
-           ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
-           ;; 20    0000 0000 1010 0000    1100 0010 1010 0000
-           ;; 7f    0000 0000 1111 1111    1100 0011 1011 1111
-           ((r0 = (((r1 & #x40) >> 6) | #xc2))
-            (r1 &= #x3f)
+         (write-repeat r1))
+
+      (if (r0 == ,(charset-id 'latin-iso8859-1))
+         ;; r1          scalar                  utf-8
+         ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
+         ;; 20    0000 0000 1010 0000    1100 0010 1010 0000
+         ;; 7f    0000 0000 1111 1111    1100 0011 1011 1111
+         ((r0 = (((r1 & #x40) >> 6) | #xc2))
+          (r1 &= #x3f)
+          (r1 |= #x80)
+          (write r0)
+          (write-repeat r1)))
+
+      (if (r0 == ,(charset-id 'mule-unicode-0100-24ff))
+         ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
+          ;; #x3f80 == (0011 1111 1000 0000)b
+          (r1 &= #x7f)
+          (r1 += (r0 + 224))           ; 240 == -32 + #x0100
+          ;; now r1 holds scalar value
+          (if (r1 < #x0800)
+              ;; 2byte encoding
+              ((write ((r1 >> 6) | #xC0))
+               (r1 &= #x3F)
+               (r1 |= #x80)
+               (write-repeat r1))
+            ;; 3byte encoding
+            ((write ((r1 >> 12) | #xE0))
+             (write  (((r1 & #x0FC0) >> 6) | #x80))
+             (r1 &= #x3F)
+             (r1 |= #x80)
+             (write-repeat r1)))))
+
+      (if (r0 == ,(charset-id 'mule-unicode-2500-33ff))
+         ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
+          (r1 &= #x7f)
+          (r1 += (r0 + 9440))          ; 9440 == -32 + #x2500
+          ;; now r1 holds scalar value
+          (write ((r1 >> 12) | #xE0))
+          (write  (((r1 & #x0FC0) >> 6) | #x80))
+          (r1 &= #x3F)
+          (r1 |= #x80)
+          (write-repeat r1)))
+
+      (if (r0 == ,(charset-id 'mule-unicode-e000-ffff))
+         ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
+          (r1 &= #x7f)
+          (r1 += (r0 + 57312))         ; 57312 == -32 + #xe000
+          ;; now r1 holds scalar value
+          (write ((r1 >> 12) | #xE0))
+          (write  (((r1 & #x0FC0) >> 6) | #x80))
+          (r1 &= #x3F)
+          (r1 |= #x80)
+          (write-repeat r1)))
+
+      (if (r0 == ,(charset-id 'eight-bit-control))
+         ;; r1          scalar                  utf-8
+         ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
+         ;; 80    0000 0000 1000 0000    1100 0010 1000 0000
+         ;; 9f    0000 0000 1001 1111    1100 0010 1001 1111
+         ((write #xC2)
+          (write-repeat r1)))
+
+      (if (r0 == ,(charset-id 'eight-bit-graphic))
+         ;; r1          scalar                  utf-8
+         ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
+         ;; a0    0000 0000 1010 0000    1100 0010 1010 0000
+         ;; ff    0000 0000 1111 1111    1101 1111 1011 1111
+         ((r0 = (r1 >= #xC0))
+          (r0 &= (r1 <= #xC3))
+          (r4 = (r1 >= #xE1))
+          (r4 &= (r1 <= #xF7))
+          (r0 |= r4)
+          (if r0
+              ((call ccl-mule-utf-8-encode-untrans)
+               (repeat))
+            (write-repeat r1))))
+
+      (lookup-character utf-subst-table-for-encode r0 r1)
+      (if r7           ; lookup succeeded
+         (if (r0 < #x800)
+             ;; 2byte encoding
+             ((write ((r0 >> 6) | #xC0))
+              (r1 &= #x3F)
+              (r1 |= #x80)
+              (write-repeat r1))
+           ;; 3byte encoding
+           ((write ((r0 >> 12) | #xE0))
+            (write  (((r0 & #x0FC0) >> 6) | #x80))
+            (r1 &= #x3F)
             (r1 |= #x80)
-            (write r0 r1))
-
-         (if (r0 == ,(charset-id 'mule-unicode-0100-24ff))
-             ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
-              ;; #x3f80 == (0011 1111 1000 0000)b
-              (r1 &= #x7f)
-              (r1 += (r0 + 224))       ; 240 == -32 + #x0100
-              ;; now r1 holds scalar value
-              (if (r1 < #x0800)
-                  ;; 2byte encoding
-                  ((r0 = (((r1 & #x07c0) >> 6) | #xc0))
-                   ;; #x07c0 == (0000 0111 1100 0000)b
-                   (r1 &= #x3f)
-                   (r1 |= #x80)
-                   (write r0 r1))
-                ;; 3byte encoding
-                ((r0 = (((r1 & #xf000) >> 12) | #xe0))
-                 (r2 = ((r1 & #x3f) | #x80))
-                 (r1 &= #x0fc0)
-                 (r1 >>= 6)
-                 (r1 |= #x80)
-                 (write r0 r1 r2))))
-
-           (if (r0 == ,(charset-id 'mule-unicode-2500-33ff))
-               ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
-                (r1 &= #x7f)
-                (r1 += (r0 + 9440))    ; 9440 == -32 + #x2500
-                (r0 = (((r1 & #xf000) >> 12) | #xe0))
-                (r2 = ((r1 & #x3f) | #x80))
-                (r1 &= #x0fc0)
-                (r1 >>= 6)
-                (r1 |= #x80)
-                (write r0 r1 r2))
-
-             (if (r0 == ,(charset-id 'mule-unicode-e000-ffff))
-                 ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
-                  (r1 &= #x7f)
-                  (r1 += (r0 + 57312)) ; 57312 == -32 + #xe000
-                  (r0 = (((r1 & #xf000) >> 12) | #xe0))
-                  (r2 = ((r1 & #x3f) | #x80))
-                  (r1 &= #x0fc0)
-                  (r1 >>= 6)
-                  (r1 |= #x80)
-                  (write r0 r1 r2))
-
-               (if (r0 == ,(charset-id 'eight-bit-control))
-                   ;; r1          scalar                  utf-8
-                   ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
-                   ;; 80    0000 0000 1000 0000    1100 0010 1000 0000
-                   ;; 9f    0000 0000 1001 1111    1100 0010 1001 1111
-                   ((write #xc2)
-                    (write r1))
-
-                 (if (r0 == ,(charset-id 'eight-bit-graphic))
-                     ;; r1          scalar                  utf-8
-                     ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
-                     ;; a0    0000 0000 1010 0000    1100 0010 1010 0000
-                     ;; ff    0000 0000 1111 1111    1101 1111 1011 1111
-                     ((write r1)
-                      (r1 = -1)
-                      (read-multibyte-character r0 r1)
-                      (if (r0 != ,(charset-id 'eight-bit-graphic))
-                          (if (r0 != ,(charset-id 'eight-bit-control))
-                              ((r5 = r0)
-                               (r6 = r1))))
-                      (if (r5 < 0)
-                          ((read-multibyte-character r0 r2)
-                           (if (r0 != ,(charset-id 'eight-bit-graphic))
-                               (if (r0 != ,(charset-id 'eight-bit-control))
-                                   ((r5 = r0)
-                                    (r6 = r2))))
-                           (if (r5 < 0)
-                               (write r1 r2)
-                             (if (r1 < #xa0)
-                                 (write r1)
-                               ((write #xc2)
-                                (write r1)))))))
-
-                   ((lookup-character utf-subst-table-for-encode r0 r1)
-                    (if r7             ; lookup succeeded
-                        ((r1 = (((r0 & #xf000) >> 12) | #xe0))
-                         (r2 = ((r0 & #x3f) | #x80))
-                         (r0 &= #x0fc0)
-                         (r0 >>= 6)
-                         (r0 |= #x80)
-                         (write r1 r0 r2))
-                      ;; Unsupported character.
-                      ;; Output U+FFFD, which is `ef bf bd' in UTF-8.
-                      ((write #xef)
-                       (write #xbf)
-                       (write #xbd)))))))))))
-      (repeat)))
-    (if (r1 >= #xa0)
-       (write r1)
-      (if (r1 >= #x80)
-         ((write #xc2)
-          (write r1)))))
+            (write-repeat r1))))
 
+      ;; Unsupported character.
+      ;; Output U+FFFD, which is `ef bf bd' in UTF-8.
+      (write #xef)
+      (write #xbf)
+      (write-repeat #xbd))))
   "CCL program to encode into UTF-8.")
 
 
 (define-ccl-program ccl-untranslated-to-ucs
   `(0
-    (if (r0 < #xf0)                    ; 3-byte encoding, as above
-       ((r4 = 0)
-        (r3 = (r1 & #b11000000))
-        (r3 |= ((r2 >> 2) & #b00110000))
-        (if (r3 != #b10100000)
-            (r4 = 1)
-          ((r3 = ((r0 & #x0f) << 12))
-           (r3 += ((r1 & #x3f) << 6))
-           (r3 += (r2 & #x3f))
-           (if (r3 < #x0800)
-               (r4 = 1))))
-        (if (r4 != 0)
-            (r0 = 0)
-          (r0 = r3)))
-      (if (r0 < #xf8)                  ; 4-byte (Mule-UCS recipe)
-         ((r4 = (r1 >> 6))
-          (if (r4 != #b10)
-              (r0 = 0)
-            ((r4 = (r2 >> 6))
-             (if (r4 != #b10)
-                 (r0 = 0)
-               ((r4 = (r3 >> 6))
-                (if (r4 != #b10)
-                    (r0 = 0)
-                  ((r1 = ((r1  & #x3F) << 12))
-                   (r2 = ((r2  & #x3F) << 6))
-                   (r3 &= #x3F)
-                   (r0 = (((((r0 & #x07) << 18) | r1) | r2) | r3)))))))))
-       (r0 = 0))))
-  "Decode 3- or 4-byte sequences in r0, r1, r2 [,r3] to unicodes in r0.
-r0 == 0 for invalid sequence.")
+    (if (r1 == 0)
+       nil
+      (if (r0 <= #xC3)                 ; 2-byte encoding
+         ((r0 = ((r0 & #x3) << 6))
+          (r0 |= (r1 & #x3F))
+          (r1 = 2))
+       (if (r2 == 0)
+           (r1 = 0)
+         (if (r0 < #xF0)               ; 3-byte encoding, as above
+             ((r0 = ((r0 & #xF) << 12))
+              (r0 |= ((r1 & #x3F) << 6))
+              (r0 |= (r1 & #x3F))
+              (r1 = 3))
+           (if (r3 == 0)
+               (r1 = 0)
+             ((r0 = ((r0 & #x7) << 18))
+              (r0 |= ((r1 & #x3F) << 12))
+              (r0 |= ((r2 & #x3F) << 6))
+              (r0 |= (r3 & #x3F))
+              (r1 = 4))))))))
+  "Decode 2-, 3-, or 4-byte sequences in r0, r1, r2 [,r3] to unicodes in r0.
+Set r1 to the byte length.  r0 == 0 for invalid sequence.")
 
 (defvar utf-8-ccl-regs (make-vector 8 0))
 
@@ -708,33 +807,47 @@ Only for 3- or 4-byte sequences."
   (aset utf-8-ccl-regs 1 (or (char-after (1+ (point))) 0))
   (aset utf-8-ccl-regs 2 (or (char-after (+ 2 (point))) 0))
   (aset utf-8-ccl-regs 3 (or (char-after (+ 3 (point))) 0))
-  (ccl-execute 'ccl-untranslated-to-ucs utf-8-ccl-regs)
-  (aref utf-8-ccl-regs 0))
+  (ccl-execute 'ccl-untranslated-to-ucs utf-8-ccl-regs))
 
 (defun utf-8-help-echo (window object position)
   (format "Untranslated Unicode U+%04X"
          (get-char-property position 'untranslated-utf-8 object)))
 
-;; We compose the untranslatable sequences into a single character.
+;; We compose the untranslatable sequences into a single character,
+;; and move point to the next character.
 ;; This is infelicitous for editing, because there's currently no
 ;; mechanism for treating compositions as atomic, but is OK for
 ;; display.  They are composed to U+FFFD with help-echo which
 ;; indicates the unicodes they represent.  This function GCs too much.
-(defsubst utf-8-compose ()
-  "Put a suitable composition on an untranslatable sequence.
-Return the sequence's length."
-  (let* ((u (utf-8-untranslated-to-ucs))
-        (l (unless (zerop u)
-             (if (>= u #x10000)
-                      4
-                    3))))
-    (when l
-      (put-text-property (point) (min (point-max) (+ l (point)))
-                        'untranslated-utf-8 u)
-      (put-text-property (point) (min (point-max) (+ l (point)))
-                        'help-echo 'utf-8-help-echo)
-      (compose-region (point) (+ l (point)) ?\e$,3u=\e(B)
-      l)))
+
+;; If utf-translate-cjk-mode is non-nil, this function is called with
+;; HASH-TABLE which translates CJK characters into some of CJK
+;; charsets.
+
+(defsubst utf-8-compose (hash-table)
+  "Put a suitable composition on an untranslatable sequence at point.
+If HASH-TABLE is non-nil, try to translate CJK characters by it at first.
+Move point to the end of the sequence."
+  (utf-8-untranslated-to-ucs)
+  (let ((l (aref utf-8-ccl-regs 1))
+       ch)
+    (if (> l 0)
+       (if (and hash-table
+                (setq ch (gethash (aref utf-8-ccl-regs 0)  hash-table)))
+           (progn
+             (insert ch)
+             (delete-region (point) (min (point-max) (+ l (point)))))
+         (setq ch (aref utf-8-ccl-regs 0))
+         (put-text-property (point) (min (point-max) (+ l (point)))
+                            'untranslated-utf-8 ch)
+         (put-text-property (point) (min (point-max) (+ l (point)))
+                            'help-echo 'utf-8-help-echo)
+         (if (= l 2)
+             (put-text-property (point) (min (point-max) (+ l (point)))
+                                'display (format "\\%03o" ch))
+           (compose-region (point) (+ l (point)) ?\e$,3u=\e(B))
+         (forward-char l))
+      (forward-char 1))))
 
 (defcustom utf-8-compose-scripts nil
   "*Non-nil means compose various scripts on decoding utf-8 text."
@@ -744,38 +857,63 @@ Return the sequence's length."
 
 (defun utf-8-post-read-conversion (length)
   "Compose untranslated utf-8 sequences into single characters.
+If `utf-translate-cjk-mode' is non-nil, tries to translate CJK characters.
 Also compose particular scripts if `utf-8-compose-scripts' is non-nil."
   (save-excursion
-    ;; Can't do eval-when-compile to insert a multibyte constant
-    ;; version of the string in the loop, since it's always loaded as
-    ;; unibyte from a byte-compiled file.
-    (let ((range (string-as-multibyte "^\xe1-\xf7")))
-      (while (and (skip-chars-forward range)
-                 (not (eobp)))
-       (forward-char (utf-8-compose)))))
-  ;; Fixme: Takahashi-san implies it may not work this easily.  I
-  ;; asked why but didn't get a reply. -- fx
-  (when (and utf-8-compose-scripts (> length 1))
-    ;; These currently have definitions which cover the relevant
-    ;; unicodes.  We could avoid loading thai-util &c by checking
-    ;; whether the region contains any characters with the appropriate
-    ;; categories.  There aren't yet Unicode-based rules for Tibetan.
-    (save-excursion (setq length (diacritic-post-read-conversion length)))
-    (save-excursion (setq length (thai-post-read-conversion length)))
-    (save-excursion (setq length (lao-post-read-conversion length)))
-    (save-excursion (setq length (devanagari-post-read-conversion length)))
-    (save-excursion (setq length (malayalam-post-read-conversion length)))
-    (save-excursion (setq length (tamil-post-read-conversion length))))
-  length)
-
-;; ucs-tables is preloaded
-;; (defun utf-8-pre-write-conversion (beg end)
-;;   "Semi-dummy pre-write function effectively to autoload ucs-tables."
-;;   ;; Ensure translation-table is loaded.
-;;   (require 'ucs-tables)
-;;   ;; Don't do this again.
-;;   (coding-system-put 'mule-utf-8 'pre-write-conversion nil)
-;;   nil)
+    (save-restriction
+      (narrow-to-region (point) (+ (point) length))
+      ;; Can't do eval-when-compile to insert a multibyte constant
+      ;; version of the string in the loop, since it's always loaded as
+      ;; unibyte from a byte-compiled file.
+      (let ((range (string-as-multibyte "^\xc0-\xc3\xe1-\xf7"))
+           hash-table ch)
+       (when utf-translate-cjk-mode
+         (if (not utf-translate-cjk-lang-env)
+             ;; Check these characters:
+             ;;   "U+2e80-U+33ff", "U+ff00-U+ffef"
+             ;; We may have to translate them to CJK charsets.
+             (let ((range2 "\e$,29@\e(B-\e$,2G\7f\e$,3r`\e(B-\e$,3u/\e(B"))
+               (skip-chars-forward (concat range range2))
+               (unless (eobp)
+                 (utf-translate-cjk-load-tables)
+                 (setq range (concat range range2)))
+         (setq hash-table (get 'utf-subst-table-for-decode
+                               'translation-hash-table)))))
+       (while (and (skip-chars-forward range)
+                   (not (eobp)))
+         (setq ch (following-char))
+         (if (< ch 256)
+             (utf-8-compose hash-table)
+           (if (and hash-table
+                    (setq ch (gethash (encode-char ch 'ucs) hash-table)))
+               (progn
+                 (insert ch)
+                 (delete-char 1))
+             (forward-char 1)))))
+
+      (when (and utf-8-compose-scripts (> length 1))
+       ;; These currently have definitions which cover the relevant
+       ;; unicodes.  We could avoid loading thai-util &c by checking
+       ;; whether the region contains any characters with the appropriate
+       ;; categories.  There aren't yet Unicode-based rules for Tibetan.
+       (diacritic-compose-region (point-max) (point-min))
+       (thai-compose-region (point-max) (point-min))
+       (lao-compose-region (point-max) (point-min))
+       (devanagari-compose-region (point-max) (point-min))
+       (malayalam-compose-region (point-max) (point-min))
+       (tamil-compose-region (point-max) (point-min)))
+      (- (point-max) (point-min)))))
+
+(defun utf-8-pre-write-conversion (beg end)
+  "Prepare for `utf-translate-cjk-mode' to encode text between BEG and END.
+This is used as a post-read-conversion of utf-8 coding system."
+  (if (and utf-translate-cjk-mode
+          (not utf-translate-cjk-lang-env)
+          (save-excursion
+            (goto-char beg)
+            (re-search-forward "\\cc\\|\\cj\\|\\ch" end t)))
+      (utf-translate-cjk-load-tables))
+  nil)
 
 (make-coding-system
  'mule-utf-8 4 ?u
@@ -797,18 +935,20 @@ any of the character sets listed above are encoded into the UTF-8 byte
 sequence representing U+FFFD (REPLACEMENT CHARACTER)."
 
  '(ccl-decode-mule-utf-8 . ccl-encode-mule-utf-8)
'((safe-charsets
`((safe-charsets
     ascii
     eight-bit-control
     eight-bit-graphic
     latin-iso8859-1
     mule-unicode-0100-24ff
     mule-unicode-2500-33ff
-    mule-unicode-e000-ffff)
+    mule-unicode-e000-ffff
+    ,@(if utf-translate-cjk-mode
+         utf-translate-cjk-charsets))
    (mime-charset . utf-8)
    (coding-category . coding-category-utf-8)
    (valid-codes (0 . 255))
-;;    (pre-write-conversion . utf-8-pre-write-conversion)
+   (pre-write-conversion . utf-8-pre-write-conversion)
    (post-read-conversion . utf-8-post-read-conversion)
    (translation-table-for-encode . utf-translation-table-for-encode)
    (dependency unify-8859-on-encoding-mode