1 ;;; mm-encode.el --- functions for encoding MIME things
2 ;; Copyright (C) 1998, 1999, 2000, 2002 Free Software Foundation, Inc.
4 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
5 ;; MORIOKA Tomohiko <morioka@jaist.ac.jp>
6 ;; This file is part of GNU Emacs.
8 ;; GNU Emacs is free software; you can redistribute it and/or modify
9 ;; it under the terms of the GNU General Public License as published by
10 ;; the Free Software Foundation; either version 2, or (at your option)
13 ;; GNU Emacs is distributed in the hope that it will be useful,
14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 ;; GNU General Public License for more details.
18 ;; You should have received a copy of the GNU General Public License
19 ;; along with GNU Emacs; see the file COPYING. If not, write to the
20 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 ;; Boston, MA 02111-1307, USA.
27 (eval-when-compile (require 'cl
))
31 (autoload 'mm-body-7-or-8
"mm-bodies"))
33 (defvar mm-content-transfer-encoding-defaults
34 '(("text/x-patch" 8bit
)
35 ("text/.*" qp-or-base64
)
36 ("message/rfc822" 8bit
)
37 ("application/emacs-lisp" 8bit
)
38 ("application/x-emacs-lisp" 8bit
)
39 ("application/x-patch" 8bit
)
41 "Alist of regexps that match MIME types and their encodings.
42 If the encoding is `qp-or-base64', then either quoted-printable
43 or base64 will be used, depending on what is more efficient.")
45 (defvar mm-use-ultra-safe-encoding nil
46 "If non-nil, use encodings aimed at Procrustean bed survival.
48 This means that textual parts are encoded as quoted-printable if they
49 contain lines longer than 76 characters or starting with \"From \" in
50 the body. Non-7bit encodings (8bit, binary) are generally disallowed.
51 This is to reduce the probability that a broken MTA or MDA changes the
54 This variable should never be set directly, but bound before a call to
55 `mml-generate-mime' or similar functions.")
57 (defun mm-insert-rfc822-headers (charset encoding
)
58 "Insert text/plain headers with CHARSET and ENCODING."
59 (insert "MIME-Version: 1.0\n")
60 (insert "Content-Type: text/plain; charset="
61 (mail-quote-string (downcase (symbol-name charset
))) "\n")
62 (insert "Content-Transfer-Encoding: "
63 (downcase (symbol-name encoding
)) "\n"))
65 (defun mm-insert-multipart-headers ()
66 "Insert multipart/mixed headers."
67 (let ((boundary "=-=-="))
68 (insert "MIME-Version: 1.0\n")
69 (insert "Content-Type: multipart/mixed; boundary=\"" boundary
"\"\n")
72 (defun mm-default-file-encoding (file)
73 "Return a default encoding for FILE."
74 (if (not (string-match "\\.[^.]+$" file
))
75 "application/octet-stream"
76 (mailcap-extension-to-mime (match-string 0 file
))))
78 (defun mm-safer-encoding (encoding)
79 "Return a safer but similar encoding."
81 ((memq encoding
'(7bit 8bit quoted-printable
)) 'quoted-printable
)
82 ;; The remaining encodings are binary and base64 (and perhaps some
83 ;; non-standard ones), which are both turned into base64.
86 (defun mm-encode-content-transfer-encoding (encoding &optional type
)
88 ((eq encoding
'quoted-printable
)
89 (quoted-printable-encode-region (point-min) (point-max) t
))
90 ((eq encoding
'base64
)
91 (when (equal type
"text/plain")
92 (goto-char (point-min))
93 (while (search-forward "\n" nil t
)
94 (replace-match "\r\n" t t
)))
96 (base64-encode-region (point-min) (point-max))
98 (message "Error while decoding: %s" error
)
100 ((memq encoding
'(7bit 8bit binary
))
106 ((functionp encoding
)
107 (ignore-errors (funcall encoding
(point-min) (point-max))))
109 (message "Unknown encoding %s; defaulting to 8bit" encoding
))))
111 (defun mm-encode-buffer (type)
112 "Encode the buffer which contains data of TYPE.
113 The encoding used is returned."
114 (let* ((mime-type (if (stringp type
) type
(car type
)))
116 (or (and (listp type
)
117 (cadr (assq 'encoding type
)))
118 (mm-content-transfer-encoding mime-type
)))
119 (bits (mm-body-7-or-8)))
120 ;; We force buffers that are 7bit to be unencoded, no matter
121 ;; what the preferred encoding is.
122 (when (eq bits
'7bit
)
123 (setq encoding bits
))
124 (mm-encode-content-transfer-encoding encoding mime-type
)
127 (defun mm-insert-headers (type encoding
&optional file
)
128 "Insert headers for TYPE."
129 (insert "Content-Type: " type
)
131 (insert ";\n\tname=\"" (file-name-nondirectory file
) "\""))
133 (insert (format "Content-Transfer-Encoding: %s\n" encoding
))
134 (insert "Content-Disposition: inline")
136 (insert ";\n\tfilename=\"" (file-name-nondirectory file
) "\""))
140 (defun mm-content-transfer-encoding (type)
141 "Return a CTE suitable for TYPE to encode the current buffer."
142 (let ((rules mm-content-transfer-encoding-defaults
))
145 (when (string-match (caar rules
) type
)
148 (if (eq (cadr (car rules
)) 'qp-or-base64
)
150 (cadr (car rules
)))))
151 (if mm-use-ultra-safe-encoding
152 (mm-safer-encoding encoding
)
156 (defun mm-qp-or-base64 ()
158 (let ((limit (min (point-max) (+ 2000 (point-min))))
160 (goto-char (point-min))
161 (skip-chars-forward "\x20-\x7f\r\n\t" limit
)
162 (while (< (point) limit
)
165 (skip-chars-forward "\x20-\x7f\r\n\t" limit
))
166 (if (or (< (* 6 n8bit
) (- limit
(point-min)))
167 ;; Don't base64, say, a short line with a single
168 ;; non-ASCII char when splitting parts by charset.
175 ;;; arch-tag: 7d01bba4-d469-4851-952b-dc863f84ed66
176 ;;; mm-encode.el ends here