Commit | Line | Data |
---|---|---|
347003be DL |
1 | ;;; utf-7.el --- utf-7 coding system |
2 | ||
49f70d46 | 3 | ;; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 |
eb3fa2cf | 4 | ;; Free Software Foundation, Inc. |
347003be DL |
5 | |
6 | ;; Author: Dave Love <fx@gnu.org> | |
7 | ;; Keywords: i18n, mail | |
8 | ||
eb3fa2cf GM |
9 | ;; This file is part of GNU Emacs. |
10 | ||
11 | ;; GNU Emacs is free software: you can redistribute it and/or modify | |
347003be | 12 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
347003be | 15 | |
eb3fa2cf | 16 | ;; GNU Emacs is distributed in the hope that it will be useful, |
347003be DL |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
eb3fa2cf | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
347003be DL |
23 | |
24 | ;;; Commentary: | |
25 | ||
26 | ;; Defines a coding system for UTF-7, defined in RFC 2152. Non-ASCII | |
27 | ;; segments are encoded as base64-encoded big endian UTF-16. Also | |
28 | ;; defines a variation required for IMAP (RFC 2060). | |
29 | ||
30 | ;; The encoding and decoding was originally taken from Jon K Hellan's | |
31 | ;; implementation in Gnus, but has been substantially re-done. | |
32 | ||
33 | ;; This probably needs more attention. In particular, it's not | |
fffa137c | 34 | ;; completely consistent with iconv's behavior. It's arguable |
347003be DL |
35 | ;; whether the IMAP version should be a coding system since it's |
36 | ;; apparently only used for IMAP mailbox names, so it's commented out. | |
37 | ||
38 | ;;; Code: | |
39 | ||
347003be DL |
40 | (defun utf-7-decode (len imap) |
41 | "Decode LEN bytes of UTF-7 at point. | |
42 | IMAP non-nil means use the IMAP version." | |
43 | (save-excursion | |
44 | (save-restriction | |
45 | (narrow-to-region (point) (+ (point) len)) | |
46 | (let ((not-esc (if imap "^&" "^+")) | |
47 | (skip-chars (if imap "A-Za-z0-9+," "A-Za-z0-9+/"))) | |
48 | (while (not (eobp)) | |
49 | (skip-chars-forward not-esc) | |
50 | (unless (eobp) | |
51 | (forward-char) | |
52 | (let ((p (point)) | |
53 | (run-length (skip-chars-forward skip-chars))) | |
54 | (if (eq ?- (char-after)) | |
55 | (delete-char 1)) | |
56 | (unless (= run-length 0) ; encoded lone esc-char | |
57 | (let ((pl (mod (- run-length) 4))) | |
58 | (insert-char ?= pl) | |
59 | (if imap | |
60 | (subst-char-in-region p (point) ?, ?/)) | |
61 | (base64-decode-region p (point))) | |
9ef9b28e | 62 | (decode-coding-region p (point) 'utf-16be) |
347003be DL |
63 | (save-excursion |
64 | (goto-char p) | |
65 | (delete-backward-char 1))))))) | |
66 | (- (point-max) (point-min))))) | |
67 | ||
a74333a1 | 68 | ;;;###autoload |
347003be DL |
69 | (defun utf-7-post-read-conversion (len) |
70 | (utf-7-decode len nil)) | |
71 | ||
7d06be9c KH |
72 | ;;;###autoload |
73 | (defun utf-7-imap-post-read-conversion (len) | |
74 | (utf-7-decode len t)) | |
347003be DL |
75 | |
76 | (defun utf-7-encode (from to imap) | |
77 | "Encode bytes between FROM and TO to UTF-7. | |
78 | ESC and SKIP-CHARS are adjusted for the normal and IMAP versions." | |
79 | (let* ((old-buf (current-buffer)) | |
80 | (esc (if imap ?& ?+)) | |
81 | ;; These are characters which can be encoded asis. | |
82 | (skip-chars (if imap | |
83 | "\t\n\r\x20-\x25\x27-\x7e" ; rfc2060 | |
84 | ;; This includes the rfc2152 optional set. | |
85 | ;; Perhaps it shouldn't (like iconv). | |
86 | "\t\n\r -*,-[]-}")) | |
87 | (not-skip-chars (format "^%s%c" skip-chars esc))) | |
88 | (set-buffer (generate-new-buffer " *temp*")) | |
89 | (if (stringp from) | |
90 | (insert from) | |
91 | (insert-buffer-substring old-buf from to)) | |
92 | (goto-char (point-min)) | |
93 | (while (not (eobp)) | |
94 | (skip-chars-forward skip-chars) | |
e9255637 | 95 | (if (eq esc (char-after)) |
347003be DL |
96 | (progn (forward-char) |
97 | (insert ?-)) | |
98 | (unless (eobp) | |
99 | (insert esc) | |
100 | (let ((p (point))) | |
101 | (skip-chars-forward not-skip-chars) | |
102 | (save-restriction | |
103 | ;; encode-coding-region doesn't preserve point | |
104 | (narrow-to-region p (point)) | |
9ef9b28e | 105 | (encode-coding-region p (point-max) 'utf-16be) |
347003be DL |
106 | (base64-encode-region p (point-max)) |
107 | (if imap | |
108 | (subst-char-in-region p (point-max) ?/ ?,)) | |
109 | (goto-char p) | |
110 | ;; As I read the RFC, this isn't correct, but it's | |
111 | ;; consistent with iconv, at least regarding `='. | |
112 | (skip-chars-forward "^= \t\n") | |
113 | (delete-region (point) (point-max)))) | |
13dbab28 SM |
114 | ;; RFC2060 stipulates that all names MUST end in US-ASCII (i.e. |
115 | ;; a name that ends with a Unicode octet MUST end with a "-"). | |
116 | (if (or imap (not (eobp))) | |
347003be DL |
117 | (insert ?-))))) |
118 | nil)) | |
119 | ||
a74333a1 | 120 | ;;;###autoload |
347003be DL |
121 | (defun utf-7-pre-write-conversion (from to) |
122 | (utf-7-encode from to nil)) | |
123 | ||
7d06be9c KH |
124 | ;;;###autoload |
125 | (defun utf-7-imap-pre-write-conversion (from to) | |
126 | (utf-7-encode from to t)) | |
347003be DL |
127 | |
128 | (provide 'utf-7) | |
ab5796a9 | 129 | |
cbee283d | 130 | ;; arch-tag: 975ee403-90a4-4286-97d2-4ed1323f4ef9 |
347003be | 131 | ;;; utf-7.el ends here |