mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-30 08:09:04 +00:00
143 lines
4.8 KiB
EmacsLisp
143 lines
4.8 KiB
EmacsLisp
;;; utf-7.el --- utf-7 coding system
|
|
|
|
;; Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
|
|
|
|
;; Author: Dave Love <fx@gnu.org>
|
|
;; Keywords: i18n, mail
|
|
|
|
;; This file 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, or (at your option)
|
|
;; any later version.
|
|
|
|
;; This file 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:
|
|
|
|
;; Defines a coding system for UTF-7, defined in RFC 2152. Non-ASCII
|
|
;; segments are encoded as base64-encoded big endian UTF-16. Also
|
|
;; defines a variation required for IMAP (RFC 2060).
|
|
|
|
;; The encoding and decoding was originally taken from Jon K Hellan's
|
|
;; implementation in Gnus, but has been substantially re-done.
|
|
|
|
;; This probably needs more attention. In particular, it's not
|
|
;; completely consistent with iconv's behaviour. It's arguable
|
|
;; whether the IMAP version should be a coding system since it's
|
|
;; apparently only used for IMAP mailbox names, so it's commented out.
|
|
|
|
;;; Code:
|
|
|
|
;;;###autoload(autoload-coding-system 'utf-7 '(require 'utf-7))
|
|
(make-coding-system
|
|
'utf-7 0 ?U
|
|
"UTF-7 encoding of Unicode (RFC 2152)"
|
|
nil
|
|
`((safe-chars . ,(coding-system-get 'utf-16be 'safe-chars))
|
|
(mime-charset . utf-7)
|
|
(pre-write-conversion . utf-7-pre-write-conversion)
|
|
(post-read-conversion . utf-7-post-read-conversion)))
|
|
|
|
;; (make-coding-system
|
|
;; 'utf-7-imap 0 ?u
|
|
;; "UTF-7 encoding of Unicode, IMAP version (RFC 2060)"
|
|
;; nil
|
|
;; `((safe-chars . ,(coding-system-get 'utf-16be 'safe-chars))
|
|
;; (pre-write-conversion . utf-7-imap-pre-write-conversion)
|
|
;; (post-read-conversion . utf-7-imap-post-read-conversion)))
|
|
|
|
(defun utf-7-decode (len imap)
|
|
"Decode LEN bytes of UTF-7 at point.
|
|
IMAP non-nil means use the IMAP version."
|
|
(save-excursion
|
|
(save-restriction
|
|
(narrow-to-region (point) (+ (point) len))
|
|
(let ((not-esc (if imap "^&" "^+"))
|
|
(skip-chars (if imap "A-Za-z0-9+," "A-Za-z0-9+/")))
|
|
(while (not (eobp))
|
|
(skip-chars-forward not-esc)
|
|
(unless (eobp)
|
|
(forward-char)
|
|
(let ((p (point))
|
|
(run-length (skip-chars-forward skip-chars)))
|
|
(if (eq ?- (char-after))
|
|
(delete-char 1))
|
|
(unless (= run-length 0) ; encoded lone esc-char
|
|
(let ((pl (mod (- run-length) 4)))
|
|
(insert-char ?= pl)
|
|
(if imap
|
|
(subst-char-in-region p (point) ?, ?/))
|
|
(base64-decode-region p (point)))
|
|
(decode-coding-region p (point) 'utf-16be)
|
|
(save-excursion
|
|
(goto-char p)
|
|
(delete-backward-char 1)))))))
|
|
(- (point-max) (point-min)))))
|
|
|
|
(defun utf-7-post-read-conversion (len)
|
|
(utf-7-decode len nil))
|
|
|
|
;; (defun utf-7-imap-post-read-conversion (len)
|
|
;; (utf-7-decode len t))
|
|
|
|
(defun utf-7-encode (from to imap)
|
|
"Encode bytes between FROM and TO to UTF-7.
|
|
ESC and SKIP-CHARS are adjusted for the normal and IMAP versions."
|
|
(let* ((old-buf (current-buffer))
|
|
(esc (if imap ?& ?+))
|
|
;; These are characters which can be encoded asis.
|
|
(skip-chars (if imap
|
|
"\t\n\r\x20-\x25\x27-\x7e" ; rfc2060
|
|
;; This includes the rfc2152 optional set.
|
|
;; Perhaps it shouldn't (like iconv).
|
|
"\t\n\r -*,-[]-}"))
|
|
(not-skip-chars (format "^%s%c" skip-chars esc)))
|
|
(set-buffer (generate-new-buffer " *temp*"))
|
|
(if (stringp from)
|
|
(insert from)
|
|
(insert-buffer-substring old-buf from to))
|
|
(goto-char (point-min))
|
|
(while (not (eobp))
|
|
(skip-chars-forward skip-chars)
|
|
(if (eq ?+ (char-after))
|
|
(progn (forward-char)
|
|
(insert ?-))
|
|
(unless (eobp)
|
|
(insert esc)
|
|
(let ((p (point)))
|
|
(skip-chars-forward not-skip-chars)
|
|
(save-restriction
|
|
;; encode-coding-region doesn't preserve point
|
|
(narrow-to-region p (point))
|
|
(encode-coding-region p (point-max) 'utf-16be)
|
|
(base64-encode-region p (point-max))
|
|
(if imap
|
|
(subst-char-in-region p (point-max) ?/ ?,))
|
|
(goto-char p)
|
|
;; As I read the RFC, this isn't correct, but it's
|
|
;; consistent with iconv, at least regarding `='.
|
|
(skip-chars-forward "^= \t\n")
|
|
(delete-region (point) (point-max))))
|
|
(unless (eobp)
|
|
(insert ?-)))))
|
|
nil))
|
|
|
|
(defun utf-7-pre-write-conversion (from to)
|
|
(utf-7-encode from to nil))
|
|
|
|
;; (defun utf-7-imap-pre-write-conversion (from to)
|
|
;; (utf-7-encode from to t))
|
|
|
|
(provide 'utf-7)
|
|
|
|
;;; arch-tag: 975ee403-90a4-4286-97d2-4ed1323f4ef9
|
|
;;; utf-7.el ends here
|