1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
;;; china-util.el --- utilities for Chinese -*- coding: iso-2022-7bit -*-
;; Copyright (C) 1995, 2001, 2002, 2003, 2004, 2005, 2006
;; Free Software Foundation, Inc.
;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
;; 2005, 2006
;; National Institute of Advanced Industrial Science and Technology (AIST)
;; Registration Number H14PRO021
;; Copyright (C) 2003
;; National Institute of Advanced Industrial Science and Technology (AIST)
;; Registration Number H13PRO009
;; Keywords: mule, multilingual, Chinese
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Commentary:
;;; Code:
;; Hz/ZW/EUC-TW encoding stuff
;; HZ is an encoding method for Chinese character set GB2312 used
;; widely in Internet. It is very similar to 7-bit environment of
;; ISO-2022. The difference is that HZ uses the sequence "~{" and
;; "~}" for designating GB2312 and ASCII respectively, hence, it
;; doesn't uses ESC (0x1B) code.
;; ZW is another encoding method for Chinese character set GB2312. It
;; encodes Chinese characters line by line by starting each line with
;; the sequence "zW". It also uses only 7-bit as HZ.
;; EUC-TW is similar to EUC-KS or EUC-JP. Its main character set is
;; plane 1 of CNS 11643; characters of planes 2 to 7 are accessed with
;; a single shift escape followed by three bytes: the first gives the
;; plane, the second and third the character code. Note that characters
;; of plane 1 are (redundantly) accessible with a single shift escape
;; also.
;; ISO-2022 escape sequence to designate GB2312.
(defvar iso2022-gb-designation "\e$A")
;; HZ escape sequence to designate GB2312.
(defvar hz-gb-designnation "~{")
;; ISO-2022 escape sequence to designate ASCII.
(defvar iso2022-ascii-designation "\e(B")
;; HZ escape sequence to designate ASCII.
(defvar hz-ascii-designnation "~}")
;; Regexp of ZW sequence to start GB2312.
(defvar zw-start-gb "^zW")
;; Regexp for start of GB2312 in an encoding mixture of HZ and ZW.
(defvar hz/zw-start-gb
(concat hz-gb-designnation "\\|" zw-start-gb "\\|[^\0-\177]"))
(defvar decode-hz-line-continuation nil
"Flag to tell if we should care line continuation convention of Hz.")
(defconst hz-set-msb-table
(eval-when-compile
(let ((chars nil)
(i 0))
(while (< i 33)
(push i chars)
(setq i (1+ i)))
(while (< i 127)
(push (decode-char 'eight-bit (+ i 128)) chars)
(setq i (1+ i)))
(apply 'string (nreverse chars)))))
;;;###autoload
(defun decode-hz-region (beg end)
"Decode HZ/ZW encoded text in the current region.
Return the length of resulting text."
(interactive "r")
(save-excursion
(save-restriction
(let (pos ch)
(narrow-to-region beg end)
;; We, at first, convert HZ/ZW to `euc-china',
;; then decode it.
;; "~\n" -> "\n", "~~" -> "~"
(goto-char (point-min))
(while (search-forward "~" nil t)
(setq ch (following-char))
(if (or (= ch ?\n) (= ch ?~)) (delete-char -1)))
;; "^zW...\n" -> Chinese GB2312
;; "~{...~}" -> Chinese GB2312
(goto-char (point-min))
(setq beg nil)
(while (re-search-forward hz/zw-start-gb nil t)
(setq pos (match-beginning 0)
ch (char-after pos))
;; Record the first position to start conversion.
(or beg (setq beg pos))
(end-of-line)
(setq end (point))
(if (>= ch 128) ; 8bit GB2312
nil
(goto-char pos)
(delete-char 2)
(setq end (- end 2))
(if (= ch ?z) ; ZW -> euc-china
(progn
(translate-region (point) end hz-set-msb-table)
(goto-char end))
(if (search-forward hz-ascii-designnation
(if decode-hz-line-continuation nil end)
t)
(delete-char -2))
(setq end (point))
(translate-region pos (point) hz-set-msb-table))))
(if beg
(decode-coding-region beg end 'euc-china)))
(- (point-max) (point-min)))))
;;;###autoload
(defun decode-hz-buffer ()
"Decode HZ/ZW encoded text in the current buffer."
(interactive)
(decode-hz-region (point-min) (point-max)))
;;;###autoload
(defun encode-hz-region (beg end)
"Encode the text in the current region to HZ.
Return the length of resulting text."
(interactive "r")
(save-excursion
(save-restriction
(narrow-to-region beg end)
;; "~" -> "~~"
(goto-char (point-min))
(while (search-forward "~" nil t) (insert ?~))
;; Chinese GB2312 -> "~{...~}"
(goto-char (point-min))
(if (re-search-forward "\\cc" nil t)
(let (pos)
(goto-char (setq pos (match-beginning 0)))
(encode-coding-region pos (point-max) 'iso-2022-7bit)
(goto-char pos)
(while (search-forward iso2022-gb-designation nil t)
(delete-char -3)
(insert hz-gb-designnation))
(goto-char pos)
(while (search-forward iso2022-ascii-designation nil t)
(delete-char -3)
(insert hz-ascii-designnation))))
(- (point-max) (point-min)))))
;;;###autoload
(defun encode-hz-buffer ()
"Encode the text in the current buffer to HZ."
(interactive)
(encode-hz-region (point-min) (point-max)))
;;;###autoload
(defun post-read-decode-hz (len)
(let ((pos (point))
(buffer-modified-p (buffer-modified-p))
last-coding-system-used)
(prog1
(decode-hz-region pos (+ pos len))
(set-buffer-modified-p buffer-modified-p))))
;;;###autoload
(defun pre-write-encode-hz (from to)
(let ((buf (current-buffer)))
(set-buffer (generate-new-buffer " *temp*"))
(if (stringp from)
(insert from)
(insert-buffer-substring buf from to))
(let (last-coding-system-used)
(encode-hz-region 1 (point-max)))
nil))
;;
(provide 'china-util)
;;; arch-tag: 5a47b084-b9ac-420e-8191-70c5b3a14836
;;; china-util.el ends here
|
