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
|
;;; puny.el --- translate non-ASCII domain names to ASCII -*- lexical-binding:t -*-
;; Copyright (C) 2015-2025 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: mail, net
;; 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 3 of the License, 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. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Written by looking at
;; https://stackoverflow.com/questions/183485/can-anyone-recommend-a-good-free-javascript-for-punycode-to-unicode-conversion
;;; Code:
(eval-when-compile (require 'cl-lib))
(require 'seq)
(defun puny-encode-domain (domain)
"Encode DOMAIN according to the IDNA/punycode algorithm.
For instance, \"fśf.org\" => \"xn--ff-2sa.org\"."
;; The vast majority of domain names are not IDNA domain names, so
;; add a check first to avoid doing unnecessary work.
(if (string-match "\\`[[:ascii:]]+\\'" domain)
domain
(mapconcat #'puny-encode-string (split-string domain "[.]") ".")))
(defun puny-encode-string (string)
"Encode STRING according to the IDNA/punycode algorithm.
This is used to encode non-ASCII domain names.
For instance, \"bücher\" => \"xn--bcher-kva\"."
(setq string (downcase (string-glyph-compose string)))
(let ((ascii (seq-filter (lambda (char)
(< char 128))
string)))
(if (= (length ascii) (length string))
string
(concat "xn--"
(if (null ascii)
""
(concat ascii "-"))
(puny-encode-complex (length ascii) string)))))
(defun puny-decode-domain (domain)
"Decode DOMAIN according to the IDNA/punycode algorithm.
For instance, \"xn--ff-2sa.org\" => \"fśf.org\"."
(mapconcat #'puny-decode-string (split-string domain "[.]") "."))
(defun puny-decode-string (string)
"Decode an IDNA/punycode-encoded string.
For instance \"xn--bcher-kva\" => \"bücher\"."
(if (string-match "\\`xn--" string)
(condition-case nil
(puny-decode-string-internal (substring string 4))
;; If the string is invalid Punycode, just return the string.
(args-out-of-range string))
string))
(defconst puny-initial-n 128)
(defconst puny-initial-bias 72)
(defconst puny-base 36)
(defconst puny-damp 700)
(defconst puny-tmin 1)
(defconst puny-tmax 26)
(defconst puny-skew 38)
;; 0-25 a-z
;; 26-36 0-9
(defun puny-encode-digit (d)
(if (< d 26)
(+ ?a d)
(+ ?0 (- d 26))))
(defun puny-adapt (delta num-points first-time)
(let ((delta (if first-time
(/ delta puny-damp)
(/ delta 2)))
(k 0))
(setq delta (+ delta (/ delta num-points)))
(while (> delta (/ (* (- puny-base puny-tmin)
puny-tmax)
2))
(setq delta (/ delta (- puny-base puny-tmin))
k (+ k puny-base)))
(+ k (/ (* (1+ (- puny-base puny-tmin)) delta)
(+ delta puny-skew)))))
(defun puny-encode-complex (insertion-points string)
(let ((n puny-initial-n)
(delta 0)
(bias puny-initial-bias)
(h insertion-points)
result m ijv q)
(while (< h (length string))
(setq ijv (cl-loop for char across string
when (>= char n)
minimize char))
(setq m ijv)
(setq delta (+ delta (* (- m n) (+ h 1)))
n m)
(cl-loop for char across string
when (< char n)
do (cl-incf delta)
when (= char ijv)
do (progn
(setq q delta)
(cl-loop with k = puny-base
for t1 = (cond
((<= k bias)
puny-tmin)
((>= k (+ bias puny-tmax))
puny-tmax)
(t
(- k bias)))
while (>= q t1)
do (push (puny-encode-digit
(+ t1 (mod (- q t1)
(- puny-base t1))))
result)
do (setq q (/ (- q t1) (- puny-base t1))
k (+ k puny-base)))
(push (puny-encode-digit q) result)
(setq bias (puny-adapt delta (+ h 1) (= h insertion-points))
delta 0
h (1+ h))))
(cl-incf delta)
(cl-incf n))
(nreverse result)))
(defun puny-decode-digit (cp)
(cond
((<= cp ?9)
(+ (- cp ?0) 26))
((<= cp ?Z)
(- cp ?A))
((<= cp ?z)
(- cp ?a))
(t
puny-base)))
(defun puny-decode-string-internal (string)
(with-temp-buffer
(insert string)
;; The encoded chars are after any final dash, else the whole string.
(let ((encoded (buffer-substring
(if (search-backward "-" nil 'move)
(1+ (point))
(point))
(point-max)))
(ic 0)
(i 0)
(bias puny-initial-bias)
(n puny-initial-n)
out)
(delete-region (point) (point-max))
(while (< ic (length encoded))
(let ((old-i i)
(w 1)
(k puny-base)
digit t1)
(cl-loop do (progn
(setq digit (puny-decode-digit (aref encoded ic)))
(cl-incf ic)
(cl-incf i (* digit w))
(setq t1 (cond
((<= k bias)
puny-tmin)
((>= k (+ bias puny-tmax))
puny-tmax)
(t
(- k bias)))))
while (>= digit t1)
do (setq w (* w (- puny-base t1))
k (+ k puny-base)))
(setq out (1+ (buffer-size)))
(setq bias (puny-adapt (- i old-i) out (= old-i 0))))
(setq n (+ n (/ i out))
i (mod i out))
(goto-char (point-min))
(forward-char i)
(insert (format "%c" n))
(cl-incf i)))
(buffer-string)))
;; https://www.unicode.org/reports/tr39/#Restriction_Level_Detection
;; https://www.unicode.org/reports/tr31/#Table_Candidate_Characters_for_Inclusion_in_Identifiers
(defun puny-highly-restrictive-string-p (string)
"Say whether STRING is \"highly restrictive\" in the Unicode IDNA sense.
See https://www.unicode.org/reports/tr39/#Restriction_Level_Detection
for details. The main idea is that if you're mixing
scripts (like latin and cyrillic), you may confuse the user by
using homographs."
(let ((scripts
(delq
t
(seq-uniq
(seq-map (lambda (char)
(if (memq char
;; These characters are always allowed
;; in any string.
'(#x0027 ; APOSTROPHE
#x002D ; HYPHEN-MINUS
#x002E ; FULL STOP
#x003A ; COLON
#x00B7 ; MIDDLE DOT
#x058A ; ARMENIAN HYPHEN
#x05F3 ; HEBREW PUNCTUATION GERESH
#x05F4 ; HEBREW PUNCTUATION GERSHAYIM
#x0F0B ; TIBETAN MARK INTERSYLLABIC TSHEG
#x200C ; ZERO WIDTH NON-JOINER*
#x200D ; ZERO WIDTH JOINER*
#x2010 ; HYPHEN
#x2019 ; RIGHT SINGLE QUOTATION MARK
#x2027 ; HYPHENATION POINT
#x30A0 ; KATAKANA-HIRAGANA DOUBLE HYPHEN
#x30FB)) ; KATAKANA MIDDLE DOT
t
(aref char-script-table char)))
string)))))
(or
;; Every character uses the same script.
(= (length scripts) 1)
(seq-some 'identity
(mapcar (lambda (list)
(seq-every-p (lambda (script)
(memq script list))
scripts))
'((latin han hiragana kana)
(latin han bopomofo)
(latin han hangul)))))))
(defun puny-highly-restrictive-domain-p (domain)
"Say whether DOMAIN is \"highly restrictive\" in the Unicode IDNA sense.
See `puny-highly-restrictive-string-p' for further details."
(seq-every-p 'puny-highly-restrictive-string-p (split-string domain "[.]")))
(provide 'puny)
;;; puny.el ends here
|
