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436 lines
13 KiB
EmacsLisp
436 lines
13 KiB
EmacsLisp
;;; rfc2047.el --- Functions for encoding and decoding rfc2047 messages
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;; Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
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;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
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;; MORIOKA Tomohiko <morioka@jaist.ac.jp>
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;;; Code:
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(eval-and-compile
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(eval
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'(unless (fboundp 'base64-decode-string)
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(require 'base64))))
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(require 'qp)
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(require 'mm-util)
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(require 'ietf-drums)
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(require 'mail-prsvr)
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(defvar rfc2047-header-encoding-alist
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'(("Newsgroups" . nil)
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("Message-ID" . nil)
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(t . mime))
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"*Header/encoding method alist.
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The list is traversed sequentially. The keys can either be
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header regexps or `t'.
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The values can be:
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1) nil, in which case no encoding is done;
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2) `mime', in which case the header will be encoded according to RFC2047;
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3) a charset, in which case it will be encoded as that charset;
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4) `default', in which case the field will be encoded as the rest
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of the article.")
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(defvar rfc2047-charset-encoding-alist
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'((us-ascii . nil)
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(iso-8859-1 . Q)
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(iso-8859-2 . Q)
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(iso-8859-3 . Q)
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(iso-8859-4 . Q)
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(iso-8859-5 . B)
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(koi8-r . B)
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(iso-8859-7 . Q)
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(iso-8859-8 . Q)
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(iso-8859-9 . Q)
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(iso-2022-jp . B)
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(iso-2022-kr . B)
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(gb2312 . B)
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(cn-gb . B)
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(cn-gb-2312 . B)
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(euc-kr . B)
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(iso-2022-jp-2 . B)
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(iso-2022-int-1 . B))
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"Alist of MIME charsets to RFC2047 encodings.
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Valid encodings are nil, `Q' and `B'.")
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(defvar rfc2047-encoding-function-alist
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'((Q . rfc2047-q-encode-region)
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(B . rfc2047-b-encode-region)
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(nil . ignore))
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"Alist of RFC2047 encodings to encoding functions.")
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(defvar rfc2047-q-encoding-alist
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'(("\\(From\\|Cc\\|To\\|Bcc\||Reply-To\\):" . "-A-Za-z0-9!*+/")
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;; = (\075), _ (\137), ? (\077) are used in the encoded word.
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;; Avoid using 8bit characters. Some versions of Emacs has bug!
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;; Equivalent to "^\000-\007\011\013\015-\037\200-\377=_?"
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("." . "\010\012\014\040-\074\076\100-\136\140-\177"))
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"Alist of header regexps and valid Q characters.")
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;;;
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;;; Functions for encoding RFC2047 messages
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;;;
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(defun rfc2047-narrow-to-field ()
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"Narrow the buffer to the header on the current line."
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(beginning-of-line)
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(narrow-to-region
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(point)
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(progn
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(forward-line 1)
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(if (re-search-forward "^[^ \n\t]" nil t)
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(progn
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(beginning-of-line)
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(point))
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(point-max))))
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(goto-char (point-min)))
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(defun rfc2047-encode-message-header ()
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"Encode the message header according to `rfc2047-header-encoding-alist'.
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Should be called narrowed to the head of the message."
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(interactive "*")
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(save-excursion
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(goto-char (point-min))
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(let (alist elem method)
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(while (not (eobp))
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(save-restriction
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(rfc2047-narrow-to-field)
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(if (not (rfc2047-encodable-p))
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(if (and (eq (mm-body-7-or-8) '8bit)
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(mm-multibyte-p)
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(mm-coding-system-p
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(car message-posting-charset)))
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;; 8 bit must be decoded.
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;; Is message-posting-charset a coding system?
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(mm-encode-coding-region
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(point-min) (point-max)
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(car message-posting-charset)))
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;; We found something that may perhaps be encoded.
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(setq method nil
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alist rfc2047-header-encoding-alist)
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(while (setq elem (pop alist))
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(when (or (and (stringp (car elem))
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(looking-at (car elem)))
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(eq (car elem) t))
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(setq alist nil
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method (cdr elem))))
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(cond
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((eq method 'mime)
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(rfc2047-encode-region (point-min) (point-max))
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(rfc2047-fold-region (point-min) (point-max)))
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((eq method 'default)
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(if (and (featurep 'mule)
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mail-parse-charset)
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(mm-encode-coding-region (point-min) (point-max)
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mail-parse-charset)))
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((mm-coding-system-p method)
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(if (featurep 'mule)
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(mm-encode-coding-region (point-min) (point-max) method)))
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;; Hm.
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(t)))
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(goto-char (point-max)))))))
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(defun rfc2047-encodable-p (&optional header)
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"Say whether the current (narrowed) buffer contains characters that need encoding in headers."
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(let ((charsets
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(mapcar
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'mm-mime-charset
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(mm-find-charset-region (point-min) (point-max))))
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(cs (list 'us-ascii (car message-posting-charset)))
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found)
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(while charsets
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(unless (memq (pop charsets) cs)
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(setq found t)))
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found))
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(defun rfc2047-dissect-region (b e)
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"Dissect the region between B and E into words."
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(let ((all-specials (concat ietf-drums-tspecials " \t\n\r"))
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(special-list (mapcar 'identity ietf-drums-tspecials))
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(blank-list '(? ?\t ?\n ?\r))
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words current cs state mail-parse-mule-charset)
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(save-restriction
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(narrow-to-region b e)
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(goto-char (point-min))
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(skip-chars-forward all-specials)
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(setq b (point))
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(while (not (eobp))
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(cond
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((not state)
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(setq state 'word)
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(if (not (eq (setq cs (mm-charset-after)) 'ascii))
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(setq current cs))
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(setq b (point)))
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((eq state 'blank)
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(cond
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((memq (char-after) special-list)
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(setq state nil))
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((memq (char-after) blank-list))
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(t
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(setq state 'word)
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(unless b
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(setq b (point)))
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(if (not (eq (setq cs (mm-charset-after)) 'ascii))
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(setq current cs)))))
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((eq state 'word)
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(cond
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((memq (char-after) special-list)
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(setq state nil)
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(push (list b (point) current) words)
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(setq current nil))
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((memq (char-after) blank-list)
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(setq state 'blank)
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(if (not current)
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(setq b nil)
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(push (list b (point) current) words)
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(setq b (point))
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(setq current nil)))
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((or (eq (setq cs (mm-charset-after)) 'ascii)
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(if current
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(eq current cs)
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(setq current cs))))
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(t
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(push (list b (point) current) words)
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(setq current cs)
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(setq b (point))))))
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(if state
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(forward-char)
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(skip-chars-forward all-specials)))
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(if (eq state 'word)
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(push (list b (point) current) words)))
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words))
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(defun rfc2047-encode-region (b e)
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"Encode all encodable words in REGION."
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(let ((words (rfc2047-dissect-region b e))
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beg end current word)
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(while (setq word (pop words))
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(if (equal (nth 2 word) current)
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(setq beg (nth 0 word))
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(when current
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(if (and (eq beg (nth 1 word)) (nth 2 word))
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(progn
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;; There might be a bug in Emacs Mule.
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;; A space must be inserted before encoding.
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(goto-char beg)
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(insert " ")
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(rfc2047-encode (1+ beg) (1+ end) current))
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(rfc2047-encode beg end current)))
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(setq current (nth 2 word)
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beg (nth 0 word)
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end (nth 1 word))))
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(when current
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(rfc2047-encode beg end current))))
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(defun rfc2047-encode-string (string)
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"Encode words in STRING."
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(with-temp-buffer
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(insert string)
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(rfc2047-encode-region (point-min) (point-max))
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(buffer-string)))
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(defun rfc2047-encode (b e charset)
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"Encode the word in the region with CHARSET."
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(let* ((mime-charset (mm-mime-charset charset))
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(encoding (or (cdr (assq mime-charset
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rfc2047-charset-encoding-alist))
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'B))
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(start (concat
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"=?" (downcase (symbol-name mime-charset)) "?"
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(downcase (symbol-name encoding)) "?"))
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(first t))
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(save-restriction
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(narrow-to-region b e)
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(when (eq encoding 'B)
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;; break into lines before encoding
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(goto-char (point-min))
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(while (not (eobp))
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(goto-char (min (point-max) (+ 15 (point))))
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(unless (eobp)
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(insert "\n"))))
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(if (and (mm-multibyte-p)
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(mm-coding-system-p mime-charset))
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(mm-encode-coding-region (point-min) (point-max) mime-charset))
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(funcall (cdr (assq encoding rfc2047-encoding-function-alist))
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(point-min) (point-max))
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(goto-char (point-min))
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(while (not (eobp))
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(unless first
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(insert " "))
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(setq first nil)
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(insert start)
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(end-of-line)
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(insert "?=")
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(forward-line 1)))))
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(defun rfc2047-fold-region (b e)
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"Fold the long lines in the region."
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(save-restriction
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(narrow-to-region b e)
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(goto-char (point-min))
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(let ((break nil))
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(while (not (eobp))
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(cond
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((memq (char-after) '(? ?\t))
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(setq break (point)))
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((and (not break)
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(looking-at "=\\?"))
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(setq break (point)))
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((and break
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(looking-at "\\?=")
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(> (- (point) (save-excursion (beginning-of-line) (point))) 76))
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(goto-char break)
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(setq break nil)
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(insert "\n ")))
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(unless (eobp)
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(forward-char 1))))))
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(defun rfc2047-b-encode-region (b e)
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"Encode the header contained in REGION with the B encoding."
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(save-restriction
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(narrow-to-region (goto-char b) e)
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(while (not (eobp))
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(base64-encode-region (point) (progn (end-of-line) (point)) t)
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(if (and (bolp) (eolp))
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(delete-backward-char 1))
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(forward-line))))
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(defun rfc2047-q-encode-region (b e)
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"Encode the header contained in REGION with the Q encoding."
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(save-excursion
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(save-restriction
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(narrow-to-region (goto-char b) e)
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(let ((alist rfc2047-q-encoding-alist))
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(while alist
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(when (looking-at (caar alist))
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(quoted-printable-encode-region b e nil (cdar alist))
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(subst-char-in-region (point-min) (point-max) ? ?_)
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(setq alist nil))
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(pop alist))
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(goto-char (point-min))
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(while (not (eobp))
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(goto-char (min (point-max) (+ 64 (point))))
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(search-backward "=" (- (point) 2) t)
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(unless (eobp)
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(insert "\n")))))))
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;;;
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;;; Functions for decoding RFC2047 messages
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;;;
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(defvar rfc2047-encoded-word-regexp
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"=\\?\\([^][\000-\040()<>@,\;:\\\"/?.=]+\\)\\?\\(B\\|Q\\)\\?\\([!->@-~ +]+\\)\\?=")
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(defun rfc2047-decode-region (start end)
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"Decode MIME-encoded words in region between START and END."
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(interactive "r")
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(let ((case-fold-search t)
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b e)
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(save-excursion
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(save-restriction
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(narrow-to-region start end)
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(goto-char (point-min))
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;; Remove whitespace between encoded words.
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(while (re-search-forward
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(concat "\\(" rfc2047-encoded-word-regexp "\\)"
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"\\(\n?[ \t]\\)+"
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"\\(" rfc2047-encoded-word-regexp "\\)")
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nil t)
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(delete-region (goto-char (match-end 1)) (match-beginning 6)))
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;; Decode the encoded words.
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(setq b (goto-char (point-min)))
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(while (re-search-forward rfc2047-encoded-word-regexp nil t)
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(setq e (match-beginning 0))
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(insert (rfc2047-parse-and-decode
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(prog1
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(match-string 0)
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(delete-region (match-beginning 0) (match-end 0)))))
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(when (and (mm-multibyte-p)
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mail-parse-charset
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(not (eq mail-parse-charset 'gnus-decoded)))
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(mm-decode-coding-region b e mail-parse-charset))
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(setq b (point)))
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(when (and (mm-multibyte-p)
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mail-parse-charset
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(not (eq mail-parse-charset 'us-ascii))
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(not (eq mail-parse-charset 'gnus-decoded)))
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(mm-decode-coding-region b (point-max) mail-parse-charset))))))
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(defun rfc2047-decode-string (string)
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"Decode the quoted-printable-encoded STRING and return the results."
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(let ((m (mm-multibyte-p)))
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(with-temp-buffer
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(when m
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(mm-enable-multibyte))
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(insert string)
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(inline
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(rfc2047-decode-region (point-min) (point-max)))
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(buffer-string))))
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(defun rfc2047-parse-and-decode (word)
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"Decode WORD and return it if it is an encoded word.
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Return WORD if not."
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(if (not (string-match rfc2047-encoded-word-regexp word))
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word
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(or
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(condition-case nil
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(rfc2047-decode
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(match-string 1 word)
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(upcase (match-string 2 word))
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(match-string 3 word))
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(error word))
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word)))
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(defun rfc2047-decode (charset encoding string)
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"Decode STRING that uses CHARSET with ENCODING.
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Valid ENCODINGs are \"B\" and \"Q\".
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If your Emacs implementation can't decode CHARSET, it returns nil."
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(if (stringp charset)
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(setq charset (intern (downcase charset))))
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(if (or (not charset)
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(eq 'gnus-all mail-parse-ignored-charsets)
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(memq 'gnus-all mail-parse-ignored-charsets)
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(memq charset mail-parse-ignored-charsets))
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(setq charset mail-parse-charset))
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(let ((cs (mm-charset-to-coding-system charset)))
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(if (and (not cs) charset
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(listp mail-parse-ignored-charsets)
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(memq 'gnus-unknown mail-parse-ignored-charsets))
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(setq cs (mm-charset-to-coding-system mail-parse-charset)))
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(when cs
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(when (and (eq cs 'ascii)
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mail-parse-charset)
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(setq cs mail-parse-charset))
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(mm-decode-coding-string
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(cond
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((equal "B" encoding)
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(base64-decode-string string))
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((equal "Q" encoding)
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(quoted-printable-decode-string
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(mm-replace-chars-in-string string ?_ ? )))
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(t (error "Invalid encoding: %s" encoding)))
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cs))))
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(provide 'rfc2047)
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;;; rfc2047.el ends here
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