lisp/international/utf-8.el

   1 ;;; utf-8.el --- UTF-8 decoding/encoding support -*- coding: iso-2022-7bit -*-
   2
   3 ;; Copyright (C) 2001, 2004 Electrotechnical Laboratory, JAPAN.
   4 ;; Licensed to the Free Software Foundation.
   5 ;; Copyright (C) 2001, 2002 Free Software Foundation, Inc.
   6
   7 ;; Author: TAKAHASHI Naoto  <ntakahas@m17n.org>
   8 ;; Maintainer: FSF
   9 ;; Keywords: multilingual, Unicode, UTF-8, i18n
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 2, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  25 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  26 ;; Boston, MA 02111-1307, USA.
  27
  28 ;;; Commentary:
  29
  30 ;; The coding-system `mule-utf-8' basically supports encoding/decoding
  31 ;; of the following character sets to and from UTF-8:
  32 ;;
  33 ;;   ascii
  34 ;;   eight-bit-control
  35 ;;   latin-iso8859-1
  36 ;;   mule-unicode-0100-24ff
  37 ;;   mule-unicode-2500-33ff
  38 ;;   mule-unicode-e000-ffff
  39 ;;
  40 ;; On decoding, Unicode characters that do not fit into the above
  41 ;; character sets are handled as `eight-bit-control' or
  42 ;; `eight-bit-graphic' characters to retain the information about the
  43 ;; original byte sequence and text properties record the corresponding
  44 ;; unicode.
  45 ;;
  46 ;; Fixme: note that reading and writing invalid utf-8 may not be
  47 ;; idempotent -- to represent the bytes to fix that needs a new charset.
  48 ;;
  49 ;; Characters from other character sets can be encoded with mule-utf-8
  50 ;; by populating the translation table
  51 ;; `utf-translation-table-for-encode'.  Hash tables
  52 ;; `utf-subst-table-for-decode' and `utf-subst-table-for-encode' are
  53 ;; used to support encoding and decoding of about a quarter of the CJK
  54 ;; space between U+3400 and U+DFFF.
  55
  56 ;; UTF-8 is defined in RFC 3629.  A sketch of the encoding is:
  57
  58 ;;        scalar       |               utf-8
  59 ;;        value        | 1st byte  | 2nd byte  | 3rd byte
  60 ;; --------------------+-----------+-----------+----------
  61 ;; 0000 0000 0xxx xxxx | 0xxx xxxx |           |
  62 ;; 0000 0yyy yyxx xxxx | 110y yyyy | 10xx xxxx |
  63 ;; zzzz yyyy yyxx xxxx | 1110 zzzz | 10yy yyyy | 10xx xxxx
  64
  65 ;;; Code:
  66
  67 (defvar ucs-mule-to-mule-unicode (make-char-table 'translation-table nil)
  68   "Char table mapping characters to latin-iso8859-1 or mule-unicode-*.
  69
  70 If `unify-8859-on-encoding-mode' is non-nil, this table populates the
  71 translation-table named `utf-translation-table-for-encode'.")
  72
  73 (define-translation-table 'utf-translation-table-for-encode)
  74
  75
  76 ;; Map Cyrillic and Greek to iso-8859 charsets, which take half the
  77 ;; space of mule-unicode.  For Latin scripts this isn't very
  78 ;; important.  Hebrew and Arabic might go here too when there's proper
  79 ;; support for them.
  80
  81 (defvar utf-fragmentation-table (make-char-table 'translation-table nil)
  82   "Char-table normally mapping non-Latin mule-unicode-* chars to iso-8859-*.
  83
  84 If `utf-fragment-on-decoding' is non-nil, this table populates the
  85 translation-table named `utf-translation-table-for-decode'")
  86
  87 (defvar utf-defragmentation-table (make-char-table 'translation-table nil)
  88   "Char-table for reverse mapping of `utf-fragmentation-table'.
  89
  90 If `utf-fragment-on-decoding' is non-nil and
  91 `unify-8859-on-encoding-mode' is nil, this table populates the
  92 translation-table named `utf-translation-table-for-encode'")
  93
  94 (define-translation-table 'utf-translation-table-for-decode)
  95
  96
  97 (defvar ucs-mule-cjk-to-unicode (make-hash-table :test 'eq)
  98   "Hash table mapping Emacs CJK character sets to Unicode code points.
  99
 100 If `utf-translate-cjk-mode' is non-nil, this table populates the
 101 translation-hash-table named `utf-subst-table-for-encode'.")
 102
 103 (define-translation-hash-table 'utf-subst-table-for-encode
 104   ucs-mule-cjk-to-unicode)
 105
 106 (defvar ucs-unicode-to-mule-cjk (make-hash-table :test 'eq)
 107   "Hash table mapping Unicode code points to Emacs CJK character sets.
 108
 109 If `utf-translate-cjk-mode' is non-nil, this table populates the
 110 translation-hash-table named `utf-subst-table-for-decode'.")
 111
 112 (define-translation-hash-table 'utf-subst-table-for-decode
 113   ucs-unicode-to-mule-cjk)
 114
 115 (mapc
 116  (lambda (pair)
 117    (aset utf-fragmentation-table (car pair) (cdr pair))
 118    (aset utf-defragmentation-table (cdr pair) (car pair)))
 119  '((?\e$,1&d\e(B . ?\e,F4\e(B) (?\e$,1&e\e(B . ?\e,F5\e(B) (?\e$,1&f\e(B . ?\e,F6\e(B) (?\e$,1&h\e(B . ?\e,F8\e(B) (?\e$,1&i\e(B . ?\e,F9\e(B)
 120    (?\e$,1&j\e(B . ?\e,F:\e(B) (?\e$,1&l\e(B . ?\e,F<\e(B) (?\e$,1&n\e(B . ?\e,F>\e(B) (?\e$,1&o\e(B . ?\e,F?\e(B) (?\e$,1&p\e(B . ?\e,F@\e(B)
 121    (?\e$,1&q\e(B . ?\e,FA\e(B) (?\e$,1&r\e(B . ?\e,FB\e(B) (?\e$,1&s\e(B . ?\e,FC\e(B) (?\e$,1&t\e(B . ?\e,FD\e(B) (?\e$,1&u\e(B . ?\e,FE\e(B)
 122    (?\e$,1&v\e(B . ?\e,FF\e(B) (?\e$,1&w\e(B . ?\e,FG\e(B) (?\e$,1&x\e(B . ?\e,FH\e(B) (?\e$,1&y\e(B . ?\e,FI\e(B) (?\e$,1&z\e(B . ?\e,FJ\e(B)
 123    (?\e$,1&{\e(B . ?\e,FK\e(B) (?\e$,1&|\e(B . ?\e,FL\e(B) (?\e$,1&}\e(B . ?\e,FM\e(B) (?\e$,1&~\e(B . ?\e,FN\e(B) (?\e$,1&\7f\e(B . ?\e,FO\e(B)
 124    (?\e$,1' \e(B . ?\e,FP\e(B) (?\e$,1'!\e(B . ?\e,FQ\e(B) (?\e$,1'#\e(B . ?\e,FS\e(B) (?\e$,1'$\e(B . ?\e,FT\e(B) (?\e$,1'%\e(B . ?\e,FU\e(B)
 125    (?\e$,1'&\e(B . ?\e,FV\e(B) (?\e$,1''\e(B . ?\e,FW\e(B) (?\e$,1'(\e(B . ?\e,FX\e(B) (?\e$,1')\e(B . ?\e,FY\e(B) (?\e$,1'*\e(B . ?\e,FZ\e(B)
 126    (?\e$,1'+\e(B . ?\e,F[\e(B) (?\e$,1',\e(B . ?\e,F\\e(B) (?\e$,1'-\e(B . ?\e,F]\e(B) (?\e$,1'.\e(B . ?\e,F^\e(B) (?\e$,1'/\e(B . ?\e,F_\e(B)
 127    (?\e$,1'0\e(B . ?\e,F`\e(B) (?\e$,1'1\e(B . ?\e,Fa\e(B) (?\e$,1'2\e(B . ?\e,Fb\e(B) (?\e$,1'3\e(B . ?\e,Fc\e(B) (?\e$,1'4\e(B . ?\e,Fd\e(B)
 128    (?\e$,1'5\e(B . ?\e,Fe\e(B) (?\e$,1'6\e(B . ?\e,Ff\e(B) (?\e$,1'7\e(B . ?\e,Fg\e(B) (?\e$,1'8\e(B . ?\e,Fh\e(B) (?\e$,1'9\e(B . ?\e,Fi\e(B)
 129    (?\e$,1':\e(B . ?\e,Fj\e(B) (?\e$,1';\e(B . ?\e,Fk\e(B) (?\e$,1'<\e(B . ?\e,Fl\e(B) (?\e$,1'=\e(B . ?\e,Fm\e(B) (?\e$,1'>\e(B . ?\e,Fn\e(B)
 130    (?\e$,1'?\e(B . ?\e,Fo\e(B) (?\e$,1'@\e(B . ?\e,Fp\e(B) (?\e$,1'A\e(B . ?\e,Fq\e(B) (?\e$,1'B\e(B . ?\e,Fr\e(B) (?\e$,1'C\e(B . ?\e,Fs\e(B)
 131    (?\e$,1'D\e(B . ?\e,Ft\e(B) (?\e$,1'E\e(B . ?\e,Fu\e(B) (?\e$,1'F\e(B . ?\e,Fv\e(B) (?\e$,1'G\e(B . ?\e,Fw\e(B) (?\e$,1'H\e(B . ?\e,Fx\e(B)
 132    (?\e$,1'I\e(B . ?\e,Fy\e(B) (?\e$,1'J\e(B . ?\e,Fz\e(B) (?\e$,1'K\e(B . ?\e,F{\e(B) (?\e$,1'L\e(B . ?\e,F|\e(B) (?\e$,1'M\e(B . ?\e,F}\e(B)
 133    (?\e$,1'N\e(B . ?\e,F~\e(B)
 134
 135    (?\e$,1(!\e(B . ?\e,L!\e(B) (?\e$,1("\e(B . ?\e,L"\e(B) (?\e$,1(#\e(B . ?\e,L#\e(B) (?\e$,1($\e(B . ?\e,L$\e(B)
 136    (?\e$,1(%\e(B . ?\e,L%\e(B) (?\e$,1(&\e(B . ?\e,L&\e(B) (?\e$,1('\e(B . ?\e,L'\e(B) (?\e$,1((\e(B . ?\e,L(\e(B) (?\e$,1()\e(B . ?\e,L)\e(B)
 137    (?\e$,1(*\e(B . ?\e,L*\e(B) (?\e$,1(+\e(B . ?\e,L+\e(B) (?\e$,1(,\e(B . ?\e,L,\e(B) (?\e$,1(.\e(B . ?\e,L.\e(B) (?\e$,1(/\e(B . ?\e,L/\e(B)
 138    (?\e$,1(0\e(B . ?\e,L0\e(B) (?\e$,1(1\e(B . ?\e,L1\e(B) (?\e$,1(2\e(B . ?\e,L2\e(B) (?\e$,1(3\e(B . ?\e,L3\e(B) (?\e$,1(4\e(B . ?\e,L4\e(B)
 139    (?\e$,1(5\e(B . ?\e,L5\e(B) (?\e$,1(6\e(B . ?\e,L6\e(B) (?\e$,1(7\e(B . ?\e,L7\e(B) (?\e$,1(8\e(B . ?\e,L8\e(B) (?\e$,1(9\e(B . ?\e,L9\e(B)
 140    (?\e$,1(:\e(B . ?\e,L:\e(B) (?\e$,1(;\e(B . ?\e,L;\e(B) (?\e$,1(<\e(B . ?\e,L<\e(B) (?\e$,1(=\e(B . ?\e,L=\e(B) (?\e$,1(>\e(B . ?\e,L>\e(B)
 141    (?\e$,1(?\e(B . ?\e,L?\e(B) (?\e$,1(@\e(B . ?\e,L@\e(B) (?\e$,1(A\e(B . ?\e,LA\e(B) (?\e$,1(B\e(B . ?\e,LB\e(B) (?\e$,1(C\e(B . ?\e,LC\e(B)
 142    (?\e$,1(D\e(B . ?\e,LD\e(B) (?\e$,1(E\e(B . ?\e,LE\e(B) (?\e$,1(F\e(B . ?\e,LF\e(B) (?\e$,1(G\e(B . ?\e,LG\e(B) (?\e$,1(H\e(B . ?\e,LH\e(B)
 143    (?\e$,1(I\e(B . ?\e,LI\e(B) (?\e$,1(J\e(B . ?\e,LJ\e(B) (?\e$,1(K\e(B . ?\e,LK\e(B) (?\e$,1(L\e(B . ?\e,LL\e(B) (?\e$,1(M\e(B . ?\e,LM\e(B)
 144    (?\e$,1(N\e(B . ?\e,LN\e(B) (?\e$,1(O\e(B . ?\e,LO\e(B) (?\e$,1(P\e(B . ?\e,LP\e(B) (?\e$,1(Q\e(B . ?\e,LQ\e(B) (?\e$,1(R\e(B . ?\e,LR\e(B)
 145    (?\e$,1(S\e(B . ?\e,LS\e(B) (?\e$,1(T\e(B . ?\e,LT\e(B) (?\e$,1(U\e(B . ?\e,LU\e(B) (?\e$,1(V\e(B . ?\e,LV\e(B) (?\e$,1(W\e(B . ?\e,LW\e(B)
 146    (?\e$,1(X\e(B . ?\e,LX\e(B) (?\e$,1(Y\e(B . ?\e,LY\e(B) (?\e$,1(Z\e(B . ?\e,LZ\e(B) (?\e$,1([\e(B . ?\e,L[\e(B) (?\e$,1(\\e(B . ?\e,L\\e(B)
 147    (?\e$,1(]\e(B . ?\e,L]\e(B) (?\e$,1(^\e(B . ?\e,L^\e(B) (?\e$,1(_\e(B . ?\e,L_\e(B) (?\e$,1(`\e(B . ?\e,L`\e(B) (?\e$,1(a\e(B . ?\e,La\e(B)
 148    (?\e$,1(b\e(B . ?\e,Lb\e(B) (?\e$,1(c\e(B . ?\e,Lc\e(B) (?\e$,1(d\e(B . ?\e,Ld\e(B) (?\e$,1(e\e(B . ?\e,Le\e(B) (?\e$,1(f\e(B . ?\e,Lf\e(B)
 149    (?\e$,1(g\e(B . ?\e,Lg\e(B) (?\e$,1(h\e(B . ?\e,Lh\e(B) (?\e$,1(i\e(B . ?\e,Li\e(B) (?\e$,1(j\e(B . ?\e,Lj\e(B) (?\e$,1(k\e(B . ?\e,Lk\e(B)
 150    (?\e$,1(l\e(B . ?\e,Ll\e(B) (?\e$,1(m\e(B . ?\e,Lm\e(B) (?\e$,1(n\e(B . ?\e,Ln\e(B) (?\e$,1(o\e(B . ?\e,Lo\e(B) (?\e$,1(q\e(B . ?\e,Lq\e(B)
 151    (?\e$,1(r\e(B . ?\e,Lr\e(B) (?\e$,1(s\e(B . ?\e,Ls\e(B) (?\e$,1(t\e(B . ?\e,Lt\e(B) (?\e$,1(u\e(B . ?\e,Lu\e(B) (?\e$,1(v\e(B . ?\e,Lv\e(B)
 152    (?\e$,1(w\e(B . ?\e,Lw\e(B) (?\e$,1(x\e(B . ?\e,Lx\e(B) (?\e$,1(y\e(B . ?\e,Ly\e(B) (?\e$,1(z\e(B . ?\e,Lz\e(B) (?\e$,1({\e(B . ?\e,L{\e(B)
 153    (?\e$,1(|\e(B . ?\e,L|\e(B) (?\e$,1(~\e(B . ?\e,L~\e(B) (?\e$,1(\7f\e(B . ?\e,L\7f\e(B)))
 154
 155
 156 (defcustom utf-fragment-on-decoding nil
 157   "Whether or not to decode some chars in UTF-8/16 text into iso8859 charsets.
 158 Setting this means that the relevant Cyrillic and Greek characters are
 159 decoded into the iso8859 charsets rather than into
 160 mule-unicode-0100-24ff.  The iso8859 charsets take half as much space
 161 in the buffer, but using them may affect how the buffer can be re-encoded
 162 and may require a different input method to search for them, for instance.
 163 See `unify-8859-on-decoding-mode' and `unify-8859-on-encoding-mode'
 164 for mechanisms to make this largely transparent.
 165
 166 Setting this variable outside customize has no effect."
 167   :set (lambda (s v)
 168          (if v
 169              (progn
 170                (define-translation-table 'utf-translation-table-for-decode
 171                  utf-fragmentation-table)
 172                ;; Even if unify-8859-on-encoding-mode is off, make
 173                ;; mule-utf-* encode characters in
 174                ;; utf-fragmentation-table.
 175                (unless (eq (get 'utf-translation-table-for-encode
 176                                 'translation-table)
 177                            ucs-mule-to-mule-unicode)
 178                  (define-translation-table 'utf-translation-table-for-encode
 179                    utf-defragmentation-table)))
 180            (define-translation-table 'utf-translation-table-for-decode)
 181            ;; When unify-8859-on-encoding-mode is off, be sure to make
 182            ;; mule-utf-* disabled for characters in
 183            ;; utf-fragmentation-table.
 184            (unless (eq (get 'utf-translation-table-for-encode
 185                             'translation-table)
 186                        ucs-mule-to-mule-unicode)
 187              (define-translation-table 'utf-translation-table-for-encode)))
 188          (set-default s v))
 189   :version "21.4"
 190   :type 'boolean
 191   :group 'mule)
 192
 193
 194 (defconst utf-translate-cjk-charsets '(chinese-gb2312
 195                                        chinese-big5-1 chinese-big5-2
 196                                        japanese-jisx0208 japanese-jisx0212
 197                                        katakana-jisx0201
 198                                        korean-ksc5601)
 199   "List of charsets supported by `utf-translate-cjk-mode'.")
 200
 201 (defvar utf-translate-cjk-lang-env nil
 202   "Language environment in which tables for `utf-translate-cjk-mode' is loaded.
 203 The value nil means that the tables are not yet loaded.")
 204
 205 (defvar utf-translate-cjk-unicode-range)
 206
 207 ;; String generated from utf-translate-cjk-unicode-range.  It is
 208 ;; suitable for an argument to skip-chars-forward.
 209 (defvar utf-translate-cjk-unicode-range-string nil)
 210
 211 (defun utf-translate-cjk-set-unicode-range (range)
 212   (setq utf-translate-cjk-unicode-range range)
 213   (setq utf-translate-cjk-unicode-range-string
 214         (let ((decode-char-no-trans
 215                #'(lambda (x)
 216                    (cond ((< x #x100) (make-char 'latin-iso8859-1 x))
 217                          ((< x #x2500)
 218                           (setq x (- x #x100))
 219                           (make-char 'mule-unicode-0100-24ff
 220                                      (+ (/ x 96) 32) (+ (% x 96) 32)))
 221                          ((< x #x3400)
 222                           (setq x (- x #x2500))
 223                           (make-char 'mule-unicode-2500-33ff
 224                                      (+ (/ x 96) 32) (+ (% x 96) 32)))
 225                          (t
 226                           (setq x (- x #xe000))
 227                           (make-char 'mule-unicode-e000-ffff
 228                                      (+ (/ x 96) 32) (+ (% x 96) 32))))))
 229               ranges from to)
 230           (dolist (elt range)
 231             (setq from (max #xA0 (car elt)) to (min #xffff (cdr elt)))
 232             (if (and (>= to #x3400) (< to #xE000))
 233                 (setq to #x33FF))
 234             (cond ((< from #x100)
 235                    (if (>= to #xE000)
 236                        (setq ranges (cons (cons #xE000 to) ranges)
 237                              to #x33FF))
 238                    (if (>= to #x2500)
 239                        (setq ranges (cons (cons #x2500 to) ranges)
 240                              to #x24FF))
 241                    (if (>= to #x100)
 242                        (setq ranges (cons (cons #x100 to) ranges)
 243                              to #xFF)))
 244                   ((< from #x2500)
 245                    (if (>= to #xE000)
 246                        (setq ranges (cons (cons #xE000 to) ranges)
 247                              to #x33FF))
 248                    (if (>= to #x2500)
 249                        (setq ranges (cons (cons #x2500 to) ranges)
 250                              to #x24FF)))
 251                   ((< from #x3400)
 252                    (if (>= to #xE000)
 253                        (setq ranges (cons (cons #xE000 to) ranges)
 254                              to #x33FF))))
 255             (if (<= from to)
 256                 (setq ranges (cons (cons from to) ranges))))
 257           (mapconcat #'(lambda (x)
 258                          (format "%c-%c"
 259                                  (funcall decode-char-no-trans (car x))
 260                                  (funcall decode-char-no-trans (cdr x))))
 261                      ranges "")))
 262   ;; These forces loading and settting tables for
 263   ;; utf-translate-cjk-mode.
 264   (setq utf-translate-cjk-lang-env nil
 265         ucs-mule-cjk-to-unicode (make-hash-table :test 'eq)
 266         ucs-unicode-to-mule-cjk (make-hash-table :test 'eq)))
 267
 268 (defcustom utf-translate-cjk-unicode-range '((#x2e80 . #xd7a3)
 269                                              (#xff00 . #xffef))
 270   "List of Unicode code ranges supported by `utf-translate-cjk-mode'.
 271 Setting this variable directly does not take effect;
 272 use either \\[customize] or the function
 273 `utf-translate-cjk-set-unicode-range'."
 274   :version "21.4"
 275   :type '(repeat (cons integer integer))
 276   :set (lambda (symbol value)
 277          (utf-translate-cjk-set-unicode-range value))
 278   :group 'mule)
 279
 280 ;; Return non-nil if CODE-POINT is in `utf-translate-cjk-unicode-range'.
 281 (defsubst utf-translate-cjk-substitutable-p (code-point)
 282   (let ((tail utf-translate-cjk-unicode-range)
 283         elt)
 284     (while tail
 285       (setq elt (car tail) tail (cdr tail))
 286       (if (and (>= code-point (car elt)) (<= code-point (cdr elt)))
 287           (setq tail nil)
 288         (setq elt nil)))
 289     elt))
 290
 291 (defun utf-translate-cjk-load-tables ()
 292   "Load tables for `utf-translate-cjk-mode'."
 293   ;; Fixme: Allow the use of the CJK charsets to be
 294   ;; customized by reordering and possible omission.
 295   (let ((redefined (< (hash-table-size ucs-mule-cjk-to-unicode) 43000)))
 296     (if redefined
 297         ;; Redefine them with realistic initial sizes and a
 298         ;; smallish rehash size to avoid wasting significant
 299         ;; space after they're built.
 300         (setq ucs-mule-cjk-to-unicode
 301               (make-hash-table :test 'eq :size 43000 :rehash-size 1000)
 302               ucs-unicode-to-mule-cjk
 303               (make-hash-table :test 'eq :size 21500 :rehash-size 1000)))
 304
 305     ;; Load the files explicitly, to avoid having to keep
 306     ;; around the large tables they contain (as well as the
 307     ;; ones which get built).
 308     (cond ((string= "Korean" current-language-environment)
 309            (load "subst-jis")
 310            (load "subst-big5")
 311            (load "subst-gb2312")
 312            (load "subst-ksc"))
 313           ((string= "Chinese-BIG5" current-language-environment)
 314            (load "subst-jis")
 315            (load "subst-ksc")
 316            (load "subst-gb2312")
 317            (load "subst-big5"))
 318           ((string= "Chinese-GB" current-language-environment)
 319            (load "subst-jis")
 320            (load "subst-ksc")
 321            (load "subst-big5")
 322            (load "subst-gb2312"))
 323           (t
 324            (load "subst-ksc")
 325            (load "subst-gb2312")
 326            (load "subst-big5")
 327            (load "subst-jis")))   ; jis covers as much as big5, gb2312
 328
 329     (when redefined
 330       (define-translation-hash-table 'utf-subst-table-for-decode
 331         ucs-unicode-to-mule-cjk)
 332       (define-translation-hash-table 'utf-subst-table-for-encode
 333         ucs-mule-cjk-to-unicode)
 334       (set-char-table-extra-slot (get 'utf-translation-table-for-encode
 335                                       'translation-table)
 336                                  1 ucs-mule-cjk-to-unicode))
 337
 338     (setq utf-translate-cjk-lang-env current-language-environment)))
 339
 340 (defun utf-lookup-subst-table-for-decode (code-point)
 341   (if (and utf-translate-cjk-mode
 342            (not utf-translate-cjk-lang-env)
 343            (utf-translate-cjk-substitutable-p code-point))
 344       (utf-translate-cjk-load-tables))
 345   (gethash code-point
 346            (get 'utf-subst-table-for-decode 'translation-hash-table)))
 347
 348
 349 (defun utf-lookup-subst-table-for-encode (char)
 350   (if (and utf-translate-cjk-mode
 351            (not utf-translate-cjk-lang-env)
 352            (memq (char-charset char) utf-translate-cjk-charsets))
 353       (utf-translate-cjk-load-tables))
 354   (gethash char
 355            (get 'utf-subst-table-for-encode 'translation-hash-table)))
 356
 357 (define-minor-mode utf-translate-cjk-mode
 358   "Toggle whether UTF based coding systems de/encode CJK characters.
 359 If ARG is an integer, enable if ARG is positive and disable if
 360 zero or negative.  This is a minor mode.
 361 Enabling this allows the coding systems mule-utf-8,
 362 mule-utf-16le and mule-utf-16be to encode characters in the charsets
 363 `korean-ksc5601', `chinese-gb2312', `chinese-big5-1',
 364 `chinese-big5-2', `japanese-jisx0208' and `japanese-jisx0212', and to
 365 decode the corresponding unicodes into such characters.
 366
 367 Where the charsets overlap, the one preferred for decoding is chosen
 368 according to the language environment in effect when this option is
 369 turned on: ksc5601 for Korean, gb2312 for Chinese-GB, big5 for
 370 Chinese-Big5 and jisx for other environments.
 371
 372 This mode is on by default.  If you are not interested in CJK
 373 characters and want to avoid some overhead on encoding/decoding
 374 by the above coding systems, you can customize the user option
 375 `utf-translate-cjk-mode' to nil."
 376   :init-value t
 377   :version "21.4"
 378   :type 'boolean
 379   :group 'mule
 380   :global t
 381   (if utf-translate-cjk-mode
 382       (progn
 383         (define-translation-hash-table 'utf-subst-table-for-decode
 384           ucs-unicode-to-mule-cjk)
 385         (define-translation-hash-table 'utf-subst-table-for-encode
 386           ucs-mule-cjk-to-unicode)
 387         (set-char-table-extra-slot (get 'utf-translation-table-for-encode
 388                                         'translation-table)
 389                                    1 ucs-mule-cjk-to-unicode))
 390     (define-translation-hash-table 'utf-subst-table-for-decode
 391       (make-hash-table :test 'eq))
 392     (define-translation-hash-table 'utf-subst-table-for-encode
 393       (make-hash-table :test 'eq))
 394     (set-char-table-extra-slot (get 'utf-translation-table-for-encode
 395                                     'translation-table)
 396                                1 nil))
 397
 398   ;; Update safe-chars of mule-utf-* coding systems.
 399   (dolist (elt (coding-system-list t))
 400     (if (string-match "^mule-utf" (symbol-name elt))
 401         (let ((safe-charsets (coding-system-get elt 'safe-charsets))
 402               (safe-chars (coding-system-get elt 'safe-chars))
 403               (need-update nil))
 404           (dolist (charset utf-translate-cjk-charsets)
 405             (unless (eq utf-translate-cjk-mode (memq charset safe-charsets))
 406               (setq safe-charsets
 407                     (if utf-translate-cjk-mode
 408                         (cons charset safe-charsets)
 409                       (delq charset safe-charsets))
 410                     need-update t)
 411               (aset safe-chars (make-char charset) utf-translate-cjk-mode)))
 412           (when need-update
 413             (coding-system-put elt 'safe-charsets safe-charsets)
 414             (define-coding-system-internal elt))))))
 415
 416 (define-ccl-program ccl-mule-utf-untrans
 417   ;; R0 is an untranslatable Unicode code-point (U+3500..U+DFFF or
 418   ;; U+10000..U+10FFFF) or an invaid byte (#x00..#xFF).  Write
 419   ;; eight-bit-control/graphic sequence (2 to 4 chars) representing
 420   ;; UTF-8 sequence of r0.  Registers r4, r5, r6 are modified.
 421   ;;
 422   ;; This is a subrountine because we assume that this is called very
 423   ;; rarely (so we don't have to worry about the overhead of the
 424   ;; call).
 425   `(0
 426     ((r5 = ,(charset-id 'eight-bit-control))
 427      (r6 = ,(charset-id 'eight-bit-graphic))
 428      (if (r0 < #x100)
 429          ((r4 = ((r0 >> 6) | #xC0))
 430           (write-multibyte-character r6 r4))
 431        ((if (r0 < #x10000)
 432             ((r4 = ((r0 >> 12) | #xE0))
 433              (write-multibyte-character r6 r4))
 434           ((r4 = ((r0 >> 18) | #xF0))
 435            (write-multibyte-character r6 r4)
 436            (r4 = (((r0 >> 12) & #x3F) | #x80))
 437            (if (r4 < #xA0)
 438                (write-multibyte-character r5 r4)
 439              (write-multibyte-character r6 r4))))
 440         (r4 = (((r0 >> 6) & #x3F) | #x80))
 441         (if (r4 < #xA0)
 442             (write-multibyte-character r5 r4)
 443           (write-multibyte-character r6 r4))))
 444      (r4 = ((r0 & #x3F) | #x80))
 445      (if (r4 < #xA0)
 446          (write-multibyte-character r5 r4)
 447        (write-multibyte-character r6 r4)))))
 448
 449 (define-ccl-program ccl-decode-mule-utf-8
 450   ;;
 451   ;;        charset         | bytes in utf-8 | bytes in emacs
 452   ;; -----------------------+----------------+---------------
 453   ;;         ascii          |       1        |       1
 454   ;; -----------------------+----------------+---------------
 455   ;;    eight-bit-control   |       2        |       2
 456   ;;    eight-bit-graphic   |       2        |       1
 457   ;;     latin-iso8859-1    |       2        |       2
 458   ;; -----------------------+----------------+---------------
 459   ;; mule-unicode-0100-24ff |       2        |       4
 460   ;;        (< 0800)        |                |
 461   ;; -----------------------+----------------+---------------
 462   ;; mule-unicode-0100-24ff |       3        |       4
 463   ;;        (>= 8000)       |                |
 464   ;; mule-unicode-2500-33ff |       3        |       4
 465   ;; mule-unicode-e000-ffff |       3        |       4
 466   ;; -----------------------+----------------+---------------
 467   ;;      invalid byte      |       1        |       2
 468   ;;
 469   ;; Thus magnification factor is two.
 470   ;;
 471   `(2
 472     ((r6 = ,(charset-id 'latin-iso8859-1))
 473      (read r0)
 474      (loop
 475       (if (r0 < #x80)
 476           ;; 1-byte encoding, i.e., ascii
 477           (write-read-repeat r0))
 478       (if (r0 < #xc2)
 479           ;; continuation byte (invalid here) or 1st byte of overlong
 480           ;; 2-byte sequence.
 481           ((call ccl-mule-utf-untrans)
 482            (r6 = ,(charset-id 'latin-iso8859-1))
 483            (read r0)
 484            (repeat)))
 485
 486       ;; Read the 2nd byte.
 487       (read r1)
 488       (if ((r1 & #b11000000) != #b10000000) ; Invalid 2nd byte
 489           ((call ccl-mule-utf-untrans)
 490            (r6 = ,(charset-id 'latin-iso8859-1))
 491            ;; Handle it in the next loop.
 492            (r0 = r1)
 493            (repeat)))
 494
 495       (if (r0 < #xe0)
 496           ;; 2-byte encoding 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
 497           ((r1 &= #x3F)
 498            (r1 |= ((r0 & #x1F) << 6))
 499            ;; Now r1 holds scalar value.  We don't have to check
 500            ;; `overlong sequence' because r0 >= 0xC2.
 501
 502            (if (r1 >= 256)
 503                ;; mule-unicode-0100-24ff (< 0800)
 504                ((r0 = r1)
 505                 (lookup-integer utf-subst-table-for-decode r0 r1)
 506                 (if (r7 == 0)
 507                     ((r0 = ,(charset-id 'mule-unicode-0100-24ff))
 508                      (r1 -= #x0100)
 509                      (r2 = (((r1 / 96) + 32) << 7))
 510                      (r1 %= 96)
 511                      (r1 += (r2 + 32))
 512                      (translate-character
 513                       utf-translation-table-for-decode r0 r1)))
 514                 (write-multibyte-character r0 r1)
 515                 (read r0)
 516                 (repeat))
 517              (if (r1 >= 160)
 518                  ;; latin-iso8859-1
 519                  ((r0 = r1)
 520                   (lookup-integer utf-subst-table-for-decode r0 r1)
 521                   (if (r7 == 0)
 522                       ((r1 -= 128)
 523                        (write-multibyte-character r6 r1))
 524                     ((write-multibyte-character r0 r1)))
 525                   (read r0)
 526                   (repeat))
 527                ;; eight-bit-control
 528                ((r0 = ,(charset-id 'eight-bit-control))
 529                 (write-multibyte-character r0 r1)
 530                 (read r0)
 531                 (repeat))))))
 532
 533       ;; Read the 3rd bytes.
 534       (read r2)
 535       (if ((r2 & #b11000000) != #b10000000) ; Invalid 3rd byte
 536           ((call ccl-mule-utf-untrans)
 537            (r0 = r1)
 538            (call ccl-mule-utf-untrans)
 539            (r6 = ,(charset-id 'latin-iso8859-1))
 540            ;; Handle it in the next loop.
 541            (r0 = r2)
 542            (repeat)))
 543
 544       (if (r0 < #xF0)
 545           ;; 3byte encoding
 546           ;; zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
 547           ((r3 = ((r0 & #xF) << 12))
 548            (r3 |= ((r1 & #x3F) << 6))
 549            (r3 |= (r2 & #x3F))
 550
 551            (if (r3 < #x800)             ; `overlong sequence'
 552                ((call ccl-mule-utf-untrans)
 553                 (r0 = r1)
 554                 (call ccl-mule-utf-untrans)
 555                 (r0 = r2)
 556                 (call ccl-mule-utf-untrans)
 557                 (r6 = ,(charset-id 'latin-iso8859-1))
 558                 (read r0)
 559                 (repeat)))
 560
 561            (if (r3 < #x2500)
 562                ;; mule-unicode-0100-24ff (>= 0800)
 563                ((r0 = r3)
 564                 (lookup-integer utf-subst-table-for-decode r0 r1)
 565                 (if (r7 == 0)
 566                     ((r0 = ,(charset-id 'mule-unicode-0100-24ff))
 567                      (r3 -= #x0100)
 568                      (r3 //= 96)
 569                      (r1 = (r7 + 32))
 570                      (r1 += ((r3 + 32) << 7))
 571                      (translate-character
 572                       utf-translation-table-for-decode r0 r1)))
 573                 (write-multibyte-character r0 r1)
 574                 (read r0)
 575                 (repeat)))
 576
 577            (if (r3 < #x3400)
 578                ;; mule-unicode-2500-33ff
 579                ((r0 = r3)               ; don't zap r3
 580                 (lookup-integer utf-subst-table-for-decode r0 r1)
 581                 (if (r7 == 0)
 582                     ((r0 = ,(charset-id 'mule-unicode-2500-33ff))
 583                      (r3 -= #x2500)
 584                      (r3 //= 96)
 585                      (r1 = (r7 + 32))
 586                      (r1 += ((r3 + 32) << 7))))
 587                 (write-multibyte-character r0 r1)
 588                 (read r0)
 589                 (repeat)))
 590
 591            (if (r3 < #xE000)
 592                ;; Try to convert to CJK chars, else
 593                ;; keep them as eight-bit-{control|graphic}.
 594                ((r0 = r3)
 595                 (lookup-integer utf-subst-table-for-decode r3 r1)
 596                 (if r7
 597                     ;; got a translation
 598                     ((write-multibyte-character r3 r1)
 599                      (read r0)
 600                      (repeat))
 601                   ((call ccl-mule-utf-untrans)
 602                    (r6 = ,(charset-id 'latin-iso8859-1))
 603                    (read r0)
 604                    (repeat)))))
 605
 606            ;; mule-unicode-e000-ffff
 607            ;; Fixme: fffe and ffff are invalid.
 608            (r0 = r3)            ; don't zap r3
 609            (lookup-integer utf-subst-table-for-decode r0 r1)
 610            (if (r7 == 0)
 611                ((r0 = ,(charset-id 'mule-unicode-e000-ffff))
 612                 (r3 -= #xe000)
 613                 (r3 //= 96)
 614                 (r1 = (r7 + 32))
 615                 (r1 += ((r3 + 32) << 7))))
 616            (write-multibyte-character r0 r1)
 617            (read r0)
 618            (repeat)))
 619
 620       ;; Read the 4th bytes.
 621       (read r3)
 622       (if ((r3 & #b11000000) != #b10000000) ; Invalid 4th byte
 623           ((call ccl-mule-utf-untrans)
 624            (r0 = r1)
 625            (call ccl-mule-utf-untrans)
 626            (r0 = r2)
 627            (call ccl-mule-utf-untrans)
 628            (r6 = ,(charset-id 'latin-iso8859-1))
 629            ;; Handle it in the next loop.
 630            (r0 = r3)
 631            (repeat)))
 632
 633       (if (r0 < #xF8)
 634           ;; 4-byte encoding:
 635           ;; wwwzzzzzzyyyyyyxxxxxx = 11110www 10zzzzzz 10yyyyyy 10xxxxxx
 636           ;; keep those bytes as eight-bit-{control|graphic}
 637           ;; Fixme: allow lookup in utf-subst-table-for-decode.
 638           ((r4 = ((r0 & #x7) << 18))
 639            (r4 |= ((r1 & #x3F) << 12))
 640            (r4 |= ((r2 & #x3F) << 6))
 641            (r4 |= (r3 & #x3F))
 642
 643            (if (r4 < #x10000)           ; `overlong sequence'
 644                ((call ccl-mule-utf-untrans)
 645                 (r0 = r1)
 646                 (call ccl-mule-utf-untrans)
 647                 (r0 = r2)
 648                 (call ccl-mule-utf-untrans)
 649                 (r0 = r3)
 650                 (call ccl-mule-utf-untrans))
 651              ((r0 = r4)
 652               (call ccl-mule-utf-untrans))))
 653
 654         ;; Unsupported sequence.
 655         ((call ccl-mule-utf-untrans)
 656          (r0 = r1)
 657          (call ccl-mule-utf-untrans)
 658          (r0 = r2)
 659          (call ccl-mule-utf-untrans)
 660          (r0 = r3)
 661          (call ccl-mule-utf-untrans)))
 662       (r6 = ,(charset-id 'latin-iso8859-1))
 663       (read r0)
 664       (repeat)))
 665
 666
 667     ;; At EOF...
 668     (if (r0 >= 0)
 669         ;; r0 >= #x80
 670         ((call ccl-mule-utf-untrans)
 671          (if (r1 >= 0)
 672              ((r0 = r1)
 673               (call ccl-mule-utf-untrans)
 674               (if (r2 >= 0)
 675                   ((r0 = r2)
 676                    (call ccl-mule-utf-untrans)
 677                    (if (r3 >= 0)
 678                        ((r0 = r3)
 679                         (call ccl-mule-utf-untrans))))))))))
 680
 681   "CCL program to decode UTF-8.
 682 Basic decoding is done into the charsets ascii, latin-iso8859-1 and
 683 mule-unicode-*, but see also `utf-fragmentation-table' and
 684 `ucs-mule-cjk-to-unicode'.
 685 Encodings of un-representable Unicode characters are decoded asis into
 686 eight-bit-control and eight-bit-graphic characters.")
 687
 688 (define-ccl-program ccl-mule-utf-8-encode-untrans
 689   ;; UTF-8 decoder generates an UTF-8 sequence represented by a
 690   ;; sequence eight-bit-control/graphic chars for an untranslatable
 691   ;; character and an invalid byte.
 692   ;;
 693   ;; This CCL parses that sequence (the first byte is already in r1),
 694   ;; writes out the original bytes of that sequence, and sets r5 to
 695   ;; -1.
 696   ;;
 697   ;; If the eight-bit-control/graphic sequence is shorter than what r1
 698   ;; suggests, it sets r5 and r6 to the last character read that
 699   ;; should be handled by the next loop of a caller.
 700   ;;
 701   ;; Note: For UTF-8 validation, we only check if a character is
 702   ;; eight-bit-control/graphic or not.  It may result in incorrect
 703   ;; handling of random binary data, but such a data can't be encoded
 704   ;; by UTF-8 anyway.  At least, UTF-8 decoders doesn't generate such
 705   ;; a sequence even if a source contains invalid byte-sequence.
 706   `(0
 707     (;; Read the 2nd byte.
 708      (read-multibyte-character r5 r6)
 709      (r0 = (r5 != ,(charset-id 'eight-bit-control)))
 710      (if ((r5 != ,(charset-id 'eight-bit-graphic)) & r0)
 711          ((write r1)                    ; invalid UTF-8
 712           (r1 = -1)
 713           (end)))
 714
 715      (if (r1 <= #xC3)
 716          ;; 2-byte sequence for an originally invalid byte.
 717          ((r6 &= #x3F)
 718           (r6 |= ((r1 & #x1F) << 6))
 719           (write r6)
 720           (r5 = -1)
 721           (end)))
 722
 723      (write r1 r6)
 724      (r2 = r1)
 725      (r1 = -1)
 726      ;; Read the 3rd byte.
 727      (read-multibyte-character r5 r6)
 728      (r0 = (r5 != ,(charset-id 'eight-bit-control)))
 729      (if ((r5 != ,(charset-id 'eight-bit-graphic)) & r0)
 730          (end))                         ; invalid UTF-8
 731      (write r6)
 732      (if (r2 < #xF0)
 733          ;; 3-byte sequence for an untranslated character.
 734          ((r5 = -1)
 735           (end)))
 736      ;; Read the 4th byte.
 737      (read-multibyte-character r5 r6)
 738      (r0 = (r5 != ,(charset-id 'eight-bit-control)))
 739      (if ((r5 != ,(charset-id 'eight-bit-graphic)) & r0)
 740          (end))                 ; invalid UTF-8
 741      ;; 4-byte sequence for an untranslated character.
 742      (write r6)
 743      (r5 = -1)
 744      (end))
 745
 746     ;; At EOF...
 747     ((r5 = -1)
 748      (if (r1 >= 0)
 749          (write r1)))))
 750
 751 (define-ccl-program ccl-encode-mule-utf-8
 752   `(1
 753     ((r5 = -1)
 754      (loop
 755       (if (r5 < 0)
 756           (read-multibyte-character r0 r1)
 757         ;; Pre-read character is in r5 (charset-ID) and r6 (code-point).
 758         ((r0 = r5)
 759          (r1 = r6)
 760          (r5 = -1)))
 761       (translate-character utf-translation-table-for-encode r0 r1)
 762
 763       (if (r0 == ,(charset-id 'ascii))
 764           (write-repeat r1))
 765
 766       (if (r0 == ,(charset-id 'latin-iso8859-1))
 767           ;; r1          scalar                  utf-8
 768           ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
 769           ;; 20    0000 0000 1010 0000    1100 0010 1010 0000
 770           ;; 7f    0000 0000 1111 1111    1100 0011 1011 1111
 771           ((write ((r1 >> 6) | #xc2))
 772            (r1 &= #x3f)
 773            (r1 |= #x80)
 774            (write-repeat r1)))
 775
 776       (if (r0 == ,(charset-id 'mule-unicode-0100-24ff))
 777           ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
 778            ;; #x3f80 == (0011 1111 1000 0000)b
 779            (r1 &= #x7f)
 780            (r1 += (r0 + 224))           ; 240 == -32 + #x0100
 781            ;; now r1 holds scalar value
 782            (if (r1 < #x0800)
 783                ;; 2byte encoding
 784                ((write ((r1 >> 6) | #xC0))
 785                 (r1 &= #x3F)
 786                 (r1 |= #x80)
 787                 (write-repeat r1))
 788              ;; 3byte encoding
 789              ((write ((r1 >> 12) | #xE0))
 790               (write  (((r1 & #x0FC0) >> 6) | #x80))
 791               (r1 &= #x3F)
 792               (r1 |= #x80)
 793               (write-repeat r1)))))
 794
 795       (if (r0 == ,(charset-id 'mule-unicode-2500-33ff))
 796           ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
 797            (r1 &= #x7f)
 798            (r1 += (r0 + 9440))          ; 9440 == -32 + #x2500
 799            ;; now r1 holds scalar value
 800            (write ((r1 >> 12) | #xE0))
 801            (write  (((r1 & #x0FC0) >> 6) | #x80))
 802            (r1 &= #x3F)
 803            (r1 |= #x80)
 804            (write-repeat r1)))
 805
 806       (if (r0 == ,(charset-id 'mule-unicode-e000-ffff))
 807           ((r0 = ((((r1 & #x3f80) >> 7) - 32) * 96))
 808            (r1 &= #x7f)
 809            (r1 += (r0 + 57312))         ; 57312 == -32 + #xe000
 810            ;; now r1 holds scalar value
 811            (write ((r1 >> 12) | #xE0))
 812            (write  (((r1 & #x0FC0) >> 6) | #x80))
 813            (r1 &= #x3F)
 814            (r1 |= #x80)
 815            (write-repeat r1)))
 816
 817       (if (r0 == ,(charset-id 'eight-bit-control))
 818           ;; r1          scalar                  utf-8
 819           ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
 820           ;; 80    0000 0000 1000 0000    1100 0010 1000 0000
 821           ;; 9f    0000 0000 1001 1111    1100 0010 1001 1111
 822           ((write #xC2)
 823            (write-repeat r1)))
 824
 825       (if (r0 == ,(charset-id 'eight-bit-graphic))
 826           ;; r1          scalar                  utf-8
 827           ;;       0000 0yyy yyxx xxxx    110y yyyy 10xx xxxx
 828           ;; a0    0000 0000 1010 0000    1100 0010 1010 0000
 829           ;; ff    0000 0000 1111 1111    1101 1111 1011 1111
 830           ((r0 = (r1 >= #xC0))
 831            (r0 &= (r1 <= #xC3))
 832            (r4 = (r1 >= #xE1))
 833            (r4 &= (r1 <= #xF7))
 834            (r0 |= r4)
 835            (if r0
 836                ((call ccl-mule-utf-8-encode-untrans)
 837                 (repeat))
 838              (write-repeat r1))))
 839
 840       (lookup-character utf-subst-table-for-encode r0 r1)
 841       (if r7            ; lookup succeeded
 842           (if (r0 < #x800)
 843               ;; 2byte encoding
 844               ((write ((r0 >> 6) | #xC0))
 845                (r0 = ((r0 & #x3F) | #x80))
 846                (write-repeat r0))
 847             ;; 3byte encoding
 848             ((write ((r0 >> 12) | #xE0))
 849              (write  (((r0 & #x0FC0) >> 6) | #x80))
 850              (r0 = ((r0 & #x3F) | #x80))
 851              (write-repeat r0))))
 852
 853       ;; Unsupported character.
 854       ;; Output U+FFFD, which is `ef bf bd' in UTF-8.
 855       (write #xef)
 856       (write #xbf)
 857       (write-repeat #xbd))))
 858   "CCL program to encode into UTF-8.")
 859
 860
 861 (define-ccl-program ccl-untranslated-to-ucs
 862   `(0
 863     (if (r1 == 0)
 864         nil
 865       (if (r0 <= #xC3)                  ; 2-byte encoding
 866           ((r0 = ((r0 & #x3) << 6))
 867            (r0 |= (r1 & #x3F))
 868            (r1 = 2))
 869         (if (r2 == 0)
 870             (r1 = 0)
 871           (if (r0 < #xF0)               ; 3-byte encoding, as above
 872               ((r0 = ((r0 & #xF) << 12))
 873                (r0 |= ((r1 & #x3F) << 6))
 874                (r0 |= (r2 & #x3F))
 875                (r1 = 3))
 876             (if (r3 == 0)
 877                 (r1 = 0)
 878               ((r0 = ((r0 & #x7) << 18))
 879                (r0 |= ((r1 & #x3F) << 12))
 880                (r0 |= ((r2 & #x3F) << 6))
 881                (r0 |= (r3 & #x3F))
 882                (r1 = 4))))))))
 883   "Decode 2-, 3-, or 4-byte sequences in r0, r1, r2 [,r3] to unicodes in r0.
 884 Set r1 to the byte length.  r0 == 0 for invalid sequence.")
 885
 886 (defvar utf-8-ccl-regs (make-vector 8 0))
 887
 888 (defsubst utf-8-untranslated-to-ucs ()
 889   "Return the UCS code for an untranslated sequence of raw bytes t point.
 890 Only for 3- or 4-byte sequences."
 891   (aset utf-8-ccl-regs 0 (or (char-after) 0))
 892   (aset utf-8-ccl-regs 1 (or (char-after (1+ (point))) 0))
 893   (aset utf-8-ccl-regs 2 (or (char-after (+ 2 (point))) 0))
 894   (aset utf-8-ccl-regs 3 (or (char-after (+ 3 (point))) 0))
 895   (ccl-execute 'ccl-untranslated-to-ucs utf-8-ccl-regs))
 896
 897 (defun utf-8-help-echo (window object position)
 898   (format "Untranslated Unicode U+%04X"
 899           (get-char-property position 'untranslated-utf-8 object)))
 900
 901 ;; We compose the untranslatable sequences into a single character,
 902 ;; and move point to the next character.
 903 ;; This is infelicitous for editing, because there's currently no
 904 ;; mechanism for treating compositions as atomic, but is OK for
 905 ;; display.  They are composed to U+FFFD with help-echo which
 906 ;; indicates the unicodes they represent.  This function GCs too much.
 907
 908 ;; If utf-translate-cjk-mode is non-nil, this function is called with
 909 ;; HASH-TABLE which translates CJK characters into some of CJK
 910 ;; charsets.
 911
 912 (defsubst utf-8-compose (hash-table)
 913   "Put a suitable composition on an untranslatable sequence at point.
 914 If HASH-TABLE is non-nil, try to translate CJK characters by it at first.
 915 Move point to the end of the sequence."
 916   (utf-8-untranslated-to-ucs)
 917   (let ((l (aref utf-8-ccl-regs 1))
 918         ch)
 919     (if (> l 0)
 920         (if (and hash-table
 921                  (setq ch (gethash (aref utf-8-ccl-regs 0)  hash-table)))
 922             (progn
 923               (insert ch)
 924               (delete-region (point) (min (point-max) (+ l (point)))))
 925           (setq ch (aref utf-8-ccl-regs 0))
 926           (put-text-property (point) (min (point-max) (+ l (point)))
 927                              'untranslated-utf-8 ch)
 928           (put-text-property (point) (min (point-max) (+ l (point)))
 929                              'help-echo 'utf-8-help-echo)
 930           (if (= l 2)
 931               (put-text-property (point) (min (point-max) (+ l (point)))
 932                                  'display (format "\\%03o" ch))
 933             (compose-region (point) (+ l (point)) ?\e$,3u=\e(B))
 934           (forward-char l))
 935       (forward-char 1))))
 936
 937 (defcustom utf-8-compose-scripts nil
 938   "*Non-nil means compose various scripts on decoding utf-8 text."
 939   :group 'mule
 940   :version "21.4"
 941   :type 'boolean)
 942
 943 (defun utf-8-post-read-conversion (length)
 944   "Compose untranslated utf-8 sequences into single characters.
 945 If `utf-translate-cjk-mode' is non-nil, tries to translate CJK characters.
 946 Also compose particular scripts if `utf-8-compose-scripts' is non-nil."
 947   (save-excursion
 948     (save-restriction
 949       (narrow-to-region (point) (+ (point) length))
 950       ;; Can't do eval-when-compile to insert a multibyte constant
 951       ;; version of the string in the loop, since it's always loaded as
 952       ;; unibyte from a byte-compiled file.
 953       (let ((range (string-as-multibyte "^\xc0-\xc3\xe1-\xf7"))
 954             (buffer-multibyte enable-multibyte-characters)
 955             hash-table ch)
 956         (set-buffer-multibyte t)
 957         (when utf-translate-cjk-mode
 958           (unless utf-translate-cjk-lang-env
 959             ;; Check these characters in utf-translate-cjk-range.
 960             ;; We may have to translate them to CJK charsets.
 961             (skip-chars-forward
 962              (concat range utf-translate-cjk-unicode-range-string))
 963             (unless (eobp)
 964               (utf-translate-cjk-load-tables)
 965               (setq range
 966                     (concat range utf-translate-cjk-unicode-range-string)))
 967             (setq hash-table (get 'utf-subst-table-for-decode
 968                                   'translation-hash-table))))
 969         (while (and (skip-chars-forward range)
 970                     (not (eobp)))
 971           (setq ch (following-char))
 972           (if (< ch 256)
 973               (utf-8-compose hash-table)
 974             (if (and hash-table
 975                      (setq ch (gethash (encode-char ch 'ucs) hash-table)))
 976                 (progn
 977                   (insert ch)
 978                   (delete-char 1))
 979               (forward-char 1))))
 980         (or buffer-multibyte
 981             (set-buffer-multibyte nil)))
 982
 983       (when (and utf-8-compose-scripts (> length 1))
 984         ;; These currently have definitions which cover the relevant
 985         ;; unicodes.  We could avoid loading thai-util &c by checking
 986         ;; whether the region contains any characters with the appropriate
 987         ;; categories.  There aren't yet Unicode-based rules for Tibetan.
 988         (diacritic-compose-region (point-max) (point-min))
 989         (thai-compose-region (point-max) (point-min))
 990         (lao-compose-region (point-max) (point-min))
 991         (devanagari-compose-region (point-max) (point-min))
 992         (malayalam-compose-region (point-max) (point-min))
 993         (tamil-compose-region (point-max) (point-min)))
 994       (- (point-max) (point-min)))))
 995
 996 (defun utf-8-pre-write-conversion (beg end)
 997   "Prepare for `utf-translate-cjk-mode' to encode text between BEG and END.
 998 This is used as a post-read-conversion of utf-8 coding system."
 999   (if (and utf-translate-cjk-mode
1000            (not utf-translate-cjk-lang-env)
1001            (save-excursion
1002              (goto-char beg)
1003              (re-search-forward "\\cc\\|\\cj\\|\\ch" end t)))
1004       (utf-translate-cjk-load-tables))
1005   nil)
1006
1007 (make-coding-system
1008  'mule-utf-8 4 ?u
1009  "UTF-8 encoding for Emacs-supported Unicode characters.
1010 It supports Unicode characters of these ranges:
1011     U+0000..U+33FF, U+E000..U+FFFF.
1012 They correspond to these Emacs character sets:
1013     ascii, latin-iso8859-1, mule-unicode-0100-24ff,
1014     mule-unicode-2500-33ff, mule-unicode-e000-ffff
1015
1016 On decoding (e.g. reading a file), Unicode characters not in the above
1017 ranges are decoded into sequences of eight-bit-control and
1018 eight-bit-graphic characters to preserve their byte sequences.  The
1019 byte sequence is preserved on i/o for valid utf-8, but not necessarily
1020 for invalid utf-8.
1021
1022 On encoding (e.g. writing a file), Emacs characters not belonging to
1023 any of the character sets listed above are encoded into the UTF-8 byte
1024 sequence representing U+FFFD (REPLACEMENT CHARACTER)."
1025
1026  '(ccl-decode-mule-utf-8 . ccl-encode-mule-utf-8)
1027  `((safe-charsets
1028     ascii
1029     eight-bit-control
1030     eight-bit-graphic
1031     latin-iso8859-1
1032     mule-unicode-0100-24ff
1033     mule-unicode-2500-33ff
1034     mule-unicode-e000-ffff
1035     ,@(if utf-translate-cjk-mode
1036           utf-translate-cjk-charsets))
1037    (mime-charset . utf-8)
1038    (coding-category . coding-category-utf-8)
1039    (valid-codes (0 . 255))
1040    (pre-write-conversion . utf-8-pre-write-conversion)
1041    (post-read-conversion . utf-8-post-read-conversion)
1042    (translation-table-for-encode . utf-translation-table-for-encode)
1043    (dependency unify-8859-on-encoding-mode
1044                unify-8859-on-decoding-mode
1045                utf-fragment-on-decoding
1046                utf-translate-cjk-mode)))
1047
1048 (define-coding-system-alias 'utf-8 'mule-utf-8)
1049
1050 ;; I think this needs special private charsets defined for the
1051 ;; untranslated sequences, if it's going to work well.
1052
1053 ;;; (defun utf-8-compose-function (pos to pattern &optional string)
1054 ;;;   (let* ((prop (get-char-property pos 'composition string))
1055 ;;;      (l (and prop (- (cadr prop) (car prop)))))
1056 ;;;     (cond ((and l (> l (- to pos)))
1057 ;;;        (delete-region pos to))
1058 ;;;       ((and (> (char-after pos) 224)
1059 ;;;             (< (char-after pos) 256)
1060 ;;;             (save-restriction
1061 ;;;               (narrow-to-region pos to)
1062 ;;;               (utf-8-compose)))
1063 ;;;        t))))
1064
1065 ;;; (dotimes (i 96)
1066 ;;;   (aset composition-function-table
1067 ;;;     (+ 128 i)
1068 ;;;     `((,(string-as-multibyte "[\200-\237\240-\377]")
1069 ;;;        . utf-8-compose-function))))
1070
1071 ;;; arch-tag: b08735b7-753b-4ae6-b754-0f3efe4515c5
1072 ;;; utf-8.el ends here