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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
|
;;; utf-16.el --- UTF-16 encoding/decoding
;; Copyright (C) 2001, 2002 Free Software Foundation, Inc.
;; Author: Dave Love <fx@gnu.org>
;; Keywords: Unicode, UTF-16, i18n
;; 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., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; Support for UTF-16, which is a two-byte encoding (modulo
;; surrogates) of Unicode, written either in little or big endian
;; order: coding-systems `mule-utf-16-le' and `mule-utf-16-be'.
;; (utf-16-le is used by the DozeN'T clipboard, for instance.) The
;; data are preceeded by a two-byte signature which identifies their
;; byte sex. These are used by the coding-category-utf-16-{b,l}e code
;; to identify the coding, but ignored on decoding.
;; Note that un-decodable sequences aren't (yet?) preserved as raw
;; bytes, as they are with utf-8, so reading and writing as utf-16 can
;; corrupt data.
;;; Code:
;; We end up with trivially different -le and -be versions of most
;; things below, sometimes with commonality abstracted into a let
;; binding for maintenance convenience.
;; We'd need new charsets distinct from ascii and eight-bit-control to
;; deal with untranslated sequences, since we can't otherwise
;; distinguish the bytes, as we can with utf-8.
;; ;; Do a multibyte write for bytes in r3 and r4.
;; ;; Intended for untranslatable utf-16 sequences.
;; (define-ccl-program ccl-mule-utf-16-untrans
;; `(0
;; (if (r3 < 128)
;; (r0 = ,(charset-id 'ascii))
;; (if (r3 < 160)
;; (r0 = ,(charset-id 'eight-bit-control))
;; (r0 = ,(charset-id 'eight-bit-graphic))))
;; (if (r4 < 128)
;; (r0 = ,(charset-id 'ascii))
;; (if (r4 < 160)
;; (r0 = ,(charset-id 'eight-bit-control))
;; (r0 = ,(charset-id 'eight-bit-graphic))))
;; (r1 = r4)))
;; "Do a multibyte write for bytes in r3 and r4.
;; First swap them if we're big endian, indicated by r5==0.
;; Intended for untranslatable utf-16 sequences.")
;; Needed in macro expansion, so can't be let-bound. Zapped after use.
(eval-and-compile
(defconst utf-16-decode-ucs
;; We have the unicode in r1. Output is charset ID in r0, code point
;; in r1.
`((lookup-integer utf-subst-table-for-decode r1 r3)
(if r7 ; got a translation
((r0 = r1) (r1 = r3))
(if (r1 < 128)
(r0 = ,(charset-id 'ascii))
(if (r1 < 160)
(r0 = ,(charset-id 'eight-bit-control))
(if (r1 < 256)
((r0 = ,(charset-id 'latin-iso8859-1))
(r1 -= 128))
(if (r1 < #x2500)
((r0 = ,(charset-id 'mule-unicode-0100-24ff))
(r1 -= #x100)
(r2 = (((r1 / 96) + 32) << 7))
(r1 %= 96)
(r1 += (r2 + 32)))
(if (r1 < #x3400)
((r0 = ,(charset-id 'mule-unicode-2500-33ff))
(r1 -= #x2500)
(r2 = (((r1 / 96) + 32) << 7))
(r1 %= 96)
(r1 += (r2 + 32)))
(if (r1 < #xd800) ; 2 untranslated bytes
;; ;; Assume this is rare, so don't worry about the
;; ;; overhead of the call.
;; (call mule-utf-16-untrans)
((r0 = ,(charset-id 'mule-unicode-e000-ffff))
(r1 = 15037)) ; U+fffd
(if (r1 < #xe000) ; surrogate
;; ((call mule-utf-16-untrans)
;; (write-multibyte-character r0 r1)
;; (read r3 r4)
;; (call mule-utf-16-untrans))
((read r3 r4)
(r0 = ,(charset-id 'mule-unicode-e000-ffff))
(r1 = 15037))
((r0 = ,(charset-id 'mule-unicode-e000-ffff))
(r1 -= #xe000)
(r2 = (((r1 / 96) + 32) << 7))
(r1 %= 96)
(r1 += (r2 + 32))))))))))))))
(define-ccl-program ccl-decode-mule-utf-16-le
`(2 ; 2 bytes -> 1 to 4 bytes
((read r0 r1) ; signature
(loop
(read r3 r4)
(r1 = (r4 <8 r3))
,utf-16-decode-ucs
(translate-character utf-translation-table-for-decode r0 r1)
(write-multibyte-character r0 r1)
(repeat))))
"Decode little endian UTF-16 (ignoring signature bytes).
Basic decoding is done into the charsets ascii, latin-iso8859-1 and
mule-unicode-*. Un-representable Unicode characters are decoded as
U+fffd. The result is run through the translation-table named
`utf-translation-table-for-decode'.")
(define-ccl-program ccl-decode-mule-utf-16-be
`(2 ; 2 bytes -> 1 to 4 bytes
((read r0 r1) ; signature
(loop
(read r3 r4)
(r1 = (r3 <8 r4))
,utf-16-decode-ucs
(translate-character utf-translation-table-for-decode r0 r1)
(write-multibyte-character r0 r1)
(repeat))))
"Decode big endian UTF-16 (ignoring signature bytes).
Basic decoding is done into the charsets ascii, latin-iso8859-1 and
mule-unicode-*. Un-representable Unicode characters are
decoded as U+fffd. The result is run through the translation-table of
name `utf-translation-table-for-decode'.")
(makunbound 'utf-16-decode-ucs) ; done with it
(eval-and-compile
(defconst utf-16-decode-to-ucs
;; CCL which, given the result of a multibyte read in r0 and r1,
;; sets r0 to the character's Unicode if the charset is one of the
;; basic utf-8 coding system ones. Otherwise set to U+fffd.
`(if (r0 == ,(charset-id 'ascii))
(r0 = r1)
(if (r0 == ,(charset-id 'latin-iso8859-1))
(r0 = (r1 + 128))
(if (r0 == ,(charset-id 'eight-bit-control))
(r0 = r1)
(if (r0 == ,(charset-id 'eight-bit-graphic))
(r0 = r1)
((r2 = (r1 & #x7f))
(r1 >>= 7)
(r3 = ((r1 - 32) * 96))
(r3 += (r2 - 32))
(if (r0 == ,(charset-id 'mule-unicode-0100-24ff))
(r0 = (r3 + #x100))
(if (r0 == ,(charset-id 'mule-unicode-2500-33ff))
(r0 = (r3 + #x2500))
(if (r0 == ,(charset-id 'mule-unicode-e000-ffff))
(r0 = (r3 + #xe000))
(r0 = #xfffd)))))))))))
(define-ccl-program ccl-encode-mule-utf-16-le
`(1
((write #xff)
(write #xfe)
(loop
(read-multibyte-character r0 r1)
(lookup-character utf-subst-table-for-encode r0 r1)
(if (r7 == 0)
((translate-character utf-translation-table-for-encode r0 r1)
,utf-16-decode-to-ucs))
(write (r0 & 255))
(write (r0 >> 8))
(repeat))))
"Encode to little endian UTF-16 with signature.
Characters from the charsets ascii, eight-bit-control,
eight-bit-graphic, latin-iso8859-1 and mule-unicode-* are encoded
after translation through the translation-table of name
`utf-translation-table-for-encode'.
Others are encoded as U+FFFD.")
(define-ccl-program ccl-encode-mule-utf-16-be
`(1
((write #xfe)
(write #xff)
(loop
(read-multibyte-character r0 r1)
(lookup-character utf-subst-table-for-encode r0 r1)
(if (r7 == 0)
((translate-character utf-translation-table-for-encode r0 r1)
,utf-16-decode-to-ucs))
(write (r0 >> 8))
(write (r0 & 255))
(repeat))))
"Encode to big endian UTF-16 with signature.
Characters from the charsets ascii, eight-bit-control,
eight-bit-graphic, latin-iso8859-1 and mule-unicode-* are encoded
after translation through the translation-table named
`utf-translation-table-for-encode'.
Others are encoded as U+FFFD.")
(makunbound 'utf-16-decode-to-ucs)
(let ((doc "
Assumes and ignores the leading two-byte signature.
It supports Unicode characters of these ranges:
U+0000..U+33FF, U+E000..U+FFFF.
They correspond to these Emacs character sets:
ascii, latin-iso8859-1, mule-unicode-0100-24ff,
mule-unicode-2500-33ff, mule-unicode-e000-ffff
On decoding (e.g. reading a file), Unicode characters not in the above
ranges are decoded as U+FFFD, effectively corrupting the data
if they are re-encoded.
On encoding (e.g. writing a file), Emacs characters not belonging to
any of the character sets listed above are encoded into the byte
sequence representing U+FFFD (REPLACEMENT CHARACTER)."))
(make-coding-system
'mule-utf-16-le 4
?u ; Mule-UCS uses ?U, but code-pages uses that for koi8-u.
(concat
"Little endian UTF-16 encoding for Emacs-supported Unicode characters."
doc)
'(ccl-decode-mule-utf-16-le . ccl-encode-mule-utf-16-le)
'((safe-charsets
ascii
eight-bit-control
latin-iso8859-1
mule-unicode-0100-24ff
mule-unicode-2500-33ff
mule-unicode-e000-ffff)
(mime-charset . utf-16le)
(coding-category . coding-category-utf-16-le)
(valid-codes (0 . 255))
(pre-write-conversion . utf-16-le-pre-write-conversion)
(dependency unify-8859-on-encoding-mode
unify-8859-on-decoding-mode
utf-fragment-on-decoding
utf-translate-cjk)))
(make-coding-system
'mule-utf-16-be 4 ?u
(concat
"Big endian UTF-16 encoding for Emacs-supported Unicode characters."
doc)
'(ccl-decode-mule-utf-16-be . ccl-encode-mule-utf-16-be)
'((safe-charsets
ascii
eight-bit-control
latin-iso8859-1
mule-unicode-0100-24ff
mule-unicode-2500-33ff
mule-unicode-e000-ffff)
(mime-charset . utf-16be)
(coding-category . coding-category-utf-16-be)
(valid-codes (0 . 255))
(pre-write-conversion . utf-16-be-pre-write-conversion)
(dependency unify-8859-on-encoding-mode
unify-8859-on-decoding-mode
utf-fragment-on-decoding
utf-translate-cjk))))
(define-coding-system-alias 'utf-16-le 'mule-utf-16-le)
(define-coding-system-alias 'utf-16-be 'mule-utf-16-be)
;;; utf-16.el ends here
|
