gnus-group.el (gnus-read-ephemeral-bug-group): Use mm-enable-multibyte instead of...
[gnus] / lisp / rfc2047.el
index 34683c3..b2520b2 100644 (file)
@@ -1,26 +1,23 @@
 ;;; rfc2047.el --- functions for encoding and decoding rfc2047 messages
 
-;; Copyright (C) 1998, 1999, 2000, 2002, 2003, 2004
-;;        Free Software Foundation, Inc.
+;; Copyright (C) 1998-2015 Free Software Foundation, Inc.
 
 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
 ;;     MORIOKA Tomohiko <morioka@jaist.ac.jp>
 ;; This file is part of GNU Emacs.
 
-;; GNU Emacs is free software; you can redistribute it and/or modify
+;; 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 2, or (at your option)
-;; any later version.
+;; 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
+;; 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., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
 
 ;;; Commentary:
 
 ;;; Code:
 
 (eval-when-compile
-  (require 'cl)
-  (defvar message-posting-charset))
+  (require 'cl))
+(defvar message-posting-charset)
 
-(require 'qp)
 (require 'mm-util)
+(require 'ietf-drums)
 ;; Fixme: Avoid this (used for mail-parse-charset) mm dependence on gnus.
 (require 'mail-prsvr)
-(require 'base64)
+(require 'rfc2045) ;; rfc2045-encode-string
 (autoload 'mm-body-7-or-8 "mm-bodies")
 
 (defvar rfc2047-header-encoding-alist
   '(("Newsgroups" . nil)
     ("Followup-To" . nil)
     ("Message-ID" . nil)
-    ("\\(Resent-\\)?\\(From\\|Cc\\|To\\|Bcc\\|Reply-To\\|Sender\
+    ("\\(Resent-\\)?\\(From\\|Cc\\|To\\|Bcc\\|\\(In-\\)?Reply-To\\|Sender\
 \\|Mail-Followup-To\\|Mail-Copies-To\\|Approved\\)" . address-mime)
     (t . mime))
   "*Header/encoding method alist.
@@ -77,6 +74,8 @@ The values can be:
     (iso-2022-jp . B)
     (iso-2022-kr . B)
     (gb2312 . B)
+    (gbk . B)
+    (gb18030 . B)
     (big5 . B)
     (cn-big5 . B)
     (cn-gb . B)
@@ -98,6 +97,40 @@ quoted-printable and base64 respectively.")
 (defvar rfc2047-encode-encoded-words t
   "Whether encoded words should be encoded again.")
 
+(defvar rfc2047-allow-irregular-q-encoded-words t
+  "*Whether to decode irregular Q-encoded words.")
+
+(eval-and-compile ;; Necessary to hard code them in `rfc2047-decode-region'.
+  (defconst rfc2047-encoded-word-regexp
+    "=\\?\\([^][\000-\040()<>@,\;:*\\\"/?.=]+\\)\\(?:\\*[^?]+\\)?\\?\
+\\(B\\?[+/0-9A-Za-z]*=*\
+\\|Q\\?[ ->@-~]*\
+\\)\\?="
+    "Regexp that matches encoded word."
+    ;; The patterns for the B encoding and the Q encoding, i.e. the ones
+    ;; beginning with "B" and "Q" respectively, are restricted into only
+    ;; the characters that those encodings may generally use.
+    )
+  (defconst rfc2047-encoded-word-regexp-loose
+    "=\\?\\([^][\000-\040()<>@,\;:*\\\"/?.=]+\\)\\(?:\\*[^?]+\\)?\\?\
+\\(B\\?[+/0-9A-Za-z]*=*\
+\\|Q\\?\\(?:\\?+[ -<>@-~]\\)?\\(?:[ ->@-~]+\\?+[ -<>@-~]\\)*[ ->@-~]*\\?*\
+\\)\\?="
+    "Regexp that matches encoded word allowing loose Q encoding."
+    ;; The pattern for the Q encoding, i.e. the one beginning with "Q",
+    ;; is similar to:
+    ;; "Q\\?\\(\\?+[^\n=?]\\)?\\([^\n?]+\\?+[^\n=?]\\)*[^\n?]*\\?*"
+    ;;      <--------1-------><----------2,3----------><--4--><-5->
+    ;; They mean:
+    ;; 1. After "Q?", allow "?"s that follow a character other than "=".
+    ;; 2. Allow "=" after "Q?"; it isn't regarded as the terminator.
+    ;; 3. In the middle of an encoded word, allow "?"s that follow a
+    ;;    character other than "=".
+    ;; 4. Allow any characters other than "?" in the middle of an
+    ;;    encoded word.
+    ;; 5. At the end, allow "?"s.
+    ))
+
 ;;;
 ;;; Functions for encoding RFC2047 messages
 ;;;
@@ -141,6 +174,55 @@ This is either `base64' or `quoted-printable'."
       (re-search-forward ":[ \t\n]*" nil t)
       (buffer-substring-no-properties (point) (point-max)))))
 
+(defun rfc2047-quote-special-characters-in-quoted-strings (&optional
+                                                          encodable-regexp)
+  "Quote special characters with `\\'s in quoted strings.
+Quoting will not be done in a quoted string if it contains characters
+matching ENCODABLE-REGEXP or it is within parentheses."
+  (goto-char (point-min))
+  (let ((tspecials (concat "[" ietf-drums-tspecials "]"))
+       (start (point))
+       beg end)
+    (with-syntax-table (standard-syntax-table)
+      (while (not (eobp))
+       (if (ignore-errors
+             (forward-list 1)
+             (eq (char-before) ?\)))
+           (forward-list -1)
+         (goto-char (point-max)))
+       (save-restriction
+         (narrow-to-region start (point))
+         (goto-char start)
+         (while (search-forward "\"" nil t)
+           (setq beg (match-beginning 0))
+           (unless (eq (char-before beg) ?\\)
+             (goto-char beg)
+             (setq beg (1+ beg))
+             (condition-case nil
+                 (progn
+                   (forward-sexp)
+                   (setq end (1- (point)))
+                   (goto-char beg)
+                   (if (and encodable-regexp
+                            (re-search-forward encodable-regexp end t))
+                       (goto-char (1+ end))
+                     (save-restriction
+                       (narrow-to-region beg end)
+                       (while (re-search-forward tspecials nil 'move)
+                         (if (eq (char-before) ?\\)
+                             (if (looking-at tspecials) ;; Already quoted.
+                                 (forward-char)
+                               (insert "\\"))
+                           (goto-char (match-beginning 0))
+                           (insert "\\")
+                           (forward-char))))
+                     (forward-char)))
+               (error
+                (goto-char beg)))))
+         (goto-char (point-max)))
+       (forward-list 1)
+       (setq start (point))))))
+
 (defvar rfc2047-encoding-type 'address-mime
   "The type of encoding done by `rfc2047-encode-region'.
 This should be dynamically bound around calls to
@@ -153,86 +235,99 @@ Should be called narrowed to the head of the message."
   (interactive "*")
   (save-excursion
     (goto-char (point-min))
-    (let (alist elem method)
+    (let (alist elem method charsets)
       (while (not (eobp))
        (save-restriction
          (rfc2047-narrow-to-field)
-         (if (not (rfc2047-encodable-p))
-             (prog1
-               (if (and (eq (mm-body-7-or-8) '8bit)
-                        (mm-multibyte-p)
-                        (mm-coding-system-p
-                         (car message-posting-charset)))
-                   ;; 8 bit must be decoded.
-                   (mm-encode-coding-region
-                    (point-min) (point-max)
-                    (mm-charset-to-coding-system
-                     (car message-posting-charset))))
-               ;; No encoding necessary, but folding is nice
-               (rfc2047-fold-region
-                (save-excursion
-                  (goto-char (point-min))
-                  (skip-chars-forward "^:")
-                  (when (looking-at ": ")
-                    (forward-char 2))
-                  (point))
-                (point-max)))
-           ;; We found something that may perhaps be encoded.
-           (setq method nil
-                 alist rfc2047-header-encoding-alist)
+         (setq method nil
+               alist rfc2047-header-encoding-alist
+               charsets (mm-find-mime-charset-region (point-min) (point-max)))
+         ;; M$ Outlook boycotts decoding of a header if it consists
+         ;; of two or more encoded words and those charsets differ;
+         ;; it seems to decode all words in a header from a charset
+         ;; found first in the header.  So, we unify the charsets into
+         ;; a single one used for encoding the whole text in a header.
+         (let ((mm-coding-system-priorities
+                (if (= (length charsets) 1)
+                    (cons (mm-charset-to-coding-system (car charsets))
+                          mm-coding-system-priorities)
+                  mm-coding-system-priorities)))
            (while (setq elem (pop alist))
              (when (or (and (stringp (car elem))
                             (looking-at (car elem)))
                        (eq (car elem) t))
                (setq alist nil
                      method (cdr elem))))
-           (goto-char (point-min))
-           (re-search-forward "^[^:]+: *" nil t)
-           (cond
-            ((eq method 'address-mime)
-             (rfc2047-encode-region (point) (point-max)))
-            ((eq method 'mime)
-             (let ((rfc2047-encoding-type 'mime))
-               (rfc2047-encode-region (point) (point-max))))
-            ((eq method 'default)
-             (if (and (featurep 'mule)
-                      (if (boundp 'default-enable-multibyte-characters)
-                          default-enable-multibyte-characters)
-                      mail-parse-charset)
-                 (mm-encode-coding-region (point) (point-max)
-                                          mail-parse-charset)))
-            ;; We get this when CC'ing messsages to newsgroups with
-            ;; 8-bit names.  The group name mail copy just got
-            ;; unconditionally encoded.  Previously, it would ask
-            ;; whether to encode, which was quite confusing for the
-            ;; user.  If the new behaviour is wrong, tell me. I have
-            ;; left the old code commented out below.
-            ;; -- Per Abrahamsen <abraham@dina.kvl.dk> Date: 2001-10-07.
-            ;; Modified by Dave Love, with the commented-out code changed
-            ;; in accordance with changes elsewhere.
-            ((null method)
-             (rfc2047-encode-region (point) (point-max)))
-;;;         ((null method)
-;;;          (if (or (message-options-get
-;;;                   'rfc2047-encode-message-header-encode-any)
-;;;                  (message-options-set
-;;;                   'rfc2047-encode-message-header-encode-any
-;;;                   (y-or-n-p
-;;;                    "Some texts are not encoded. Encode anyway?")))
-;;;              (rfc2047-encode-region (point-min) (point-max))
-;;;            (error "Cannot send unencoded text")))
-            ((mm-coding-system-p method)
-             (if (and (featurep 'mule)
-                      (if (boundp 'default-enable-multibyte-characters)
-                          default-enable-multibyte-characters))
-                 (mm-encode-coding-region (point) (point-max) method)))
-            ;; Hm.
-            (t)))
-         (goto-char (point-max)))))))
+           (if (not (rfc2047-encodable-p))
+               (prog2
+                   (when (eq method 'address-mime)
+                     (rfc2047-quote-special-characters-in-quoted-strings))
+                   (if (and (eq (mm-body-7-or-8) '8bit)
+                            (mm-multibyte-p)
+                            (mm-coding-system-p
+                             (car message-posting-charset)))
+                       ;; 8 bit must be decoded.
+                       (mm-encode-coding-region
+                        (point-min) (point-max)
+                        (mm-charset-to-coding-system
+                         (car message-posting-charset))))
+                 ;; No encoding necessary, but folding is nice
+                 (when nil
+                   (rfc2047-fold-region
+                    (save-excursion
+                      (goto-char (point-min))
+                      (skip-chars-forward "^:")
+                      (when (looking-at ": ")
+                        (forward-char 2))
+                      (point))
+                    (point-max))))
+             ;; We found something that may perhaps be encoded.
+             (re-search-forward "^[^:]+: *" nil t)
+             (cond
+              ((eq method 'address-mime)
+               (rfc2047-encode-region (point) (point-max)))
+              ((eq method 'mime)
+               (let ((rfc2047-encoding-type 'mime))
+                 (rfc2047-encode-region (point) (point-max))))
+              ((eq method 'default)
+               (if (and (featurep 'mule)
+                        (if (boundp 'enable-multibyte-characters)
+                            (default-value 'enable-multibyte-characters))
+                        mail-parse-charset)
+                   (mm-encode-coding-region (point) (point-max)
+                                            mail-parse-charset)))
+              ;; We get this when CC'ing messages to newsgroups with
+              ;; 8-bit names.  The group name mail copy just got
+              ;; unconditionally encoded.  Previously, it would ask
+              ;; whether to encode, which was quite confusing for the
+              ;; user.  If the new behavior is wrong, tell me.  I have
+              ;; left the old code commented out below.
+              ;; -- Per Abrahamsen <abraham@dina.kvl.dk> Date: 2001-10-07.
+              ;; Modified by Dave Love, with the commented-out code changed
+              ;; in accordance with changes elsewhere.
+              ((null method)
+               (rfc2047-encode-region (point) (point-max)))
+;;;           ((null method)
+;;;            (if (or (message-options-get
+;;;                     'rfc2047-encode-message-header-encode-any)
+;;;                    (message-options-set
+;;;                     'rfc2047-encode-message-header-encode-any
+;;;                     (y-or-n-p
+;;;                      "Some texts are not encoded. Encode anyway?")))
+;;;                (rfc2047-encode-region (point-min) (point-max))
+;;;              (error "Cannot send unencoded text")))
+              ((mm-coding-system-p method)
+               (if (or (and (featurep 'mule)
+                            (if (boundp 'enable-multibyte-characters)
+                                (default-value 'enable-multibyte-characters)))
+                       (featurep 'file-coding))
+                   (mm-encode-coding-region (point) (point-max) method)))
+              ;; Hm.
+              (t)))
+           (goto-char (point-max))))))))
 
 ;; Fixme: This, and the require below may not be the Right Thing, but
 ;; should be safe just before release.  -- fx 2001-02-08
-(eval-when-compile (defvar message-posting-charset))
 
 (defun rfc2047-encodable-p ()
   "Return non-nil if any characters in current buffer need encoding in headers.
@@ -243,7 +338,7 @@ The buffer may be narrowed."
     (goto-char (point-min))
     (or (and rfc2047-encode-encoded-words
             (prog1
-                (search-forward "=?" nil t)
+                (re-search-forward rfc2047-encoded-word-regexp nil t)
               (goto-char (point-min))))
        (and charsets
             (not (equal charsets (list (car message-posting-charset))))))))
@@ -257,21 +352,17 @@ The buffer may be narrowed."
 (defconst rfc2047-syntax-table
   ;; (make-char-table 'syntax-table '(2)) only works in Emacs.
   (let ((table (make-syntax-table)))
-    ;; The following is done to work for setting all elements of the table
-    ;; in Emacs 21 and 22 and XEmacs; it appears to be the cleanest way.
+    ;; The following is done to work for setting all elements of the table;
+    ;; it appears to be the cleanest way.
     ;; Play safe and don't assume the form of the word syntax entry --
     ;; copy it from ?a.
-    (if (fboundp 'set-char-table-range)        ; Emacs
-       (funcall (intern "set-char-table-range")
-                table t (aref (standard-syntax-table) ?a))
-      (if (fboundp 'put-char-table)
-         (if (fboundp 'get-char-table) ; warning avoidance
-             (put-char-table t (get-char-table ?a (standard-syntax-table))
-                             table))))
+    (if (featurep 'xemacs)
+       (put-char-table t (get-char-table ?a (standard-syntax-table)) table)
+      (set-char-table-range table t (aref (standard-syntax-table) ?a)))
     (modify-syntax-entry ?\\ "\\" table)
     (modify-syntax-entry ?\" "\"" table)
-    (modify-syntax-entry ?\( "." table)
-    (modify-syntax-entry ?\) "." table)
+    (modify-syntax-entry ?\( "(" table)
+    (modify-syntax-entry ?\) ")" table)
     (modify-syntax-entry ?\< "." table)
     (modify-syntax-entry ?\> "." table)
     (modify-syntax-entry ?\[ "." table)
@@ -282,20 +373,21 @@ The buffer may be narrowed."
     (modify-syntax-entry ?@ "." table)
     table))
 
-(defun rfc2047-encode-region (b e)
+(defun rfc2047-encode-region (b e &optional dont-fold)
   "Encode words in region B to E that need encoding.
 By default, the region is treated as containing RFC2822 addresses.
 Dynamically bind `rfc2047-encoding-type' to change that."
   (save-restriction
     (narrow-to-region b e)
     (let ((encodable-regexp (if rfc2047-encode-encoded-words
-                               "[^\000-\177]\\|=\\?"
-                             "[^\000-\177]"))
+                               "[^\000-\177]+\\|=\\?"
+                             "[^\000-\177]+"))
          start                         ; start of current token
-         end                           ; end of current token
+         end begin csyntax
          ;; Whether there's an encoded word before the current token,
          ;; either immediately or separated by space.
-         last-encoded)
+         last-encoded
+         (orig-text (buffer-substring-no-properties b e)))
       (if (eq 'mime rfc2047-encoding-type)
          ;; Simple case.  Continuous words in which all those contain
          ;; non-ASCII characters are encoded collectively.  Encoding
@@ -316,9 +408,10 @@ Dynamically bind `rfc2047-encoding-type' to change that."
                  (rfc2047-encode start (point))
                (goto-char end))))
        ;; `address-mime' case -- take care of quoted words, comments.
+       (rfc2047-quote-special-characters-in-quoted-strings encodable-regexp)
        (with-syntax-table rfc2047-syntax-table
          (goto-char (point-min))
-         (condition-case nil           ; in case of unbalanced quotes
+         (condition-case err           ; in case of unbalanced quotes
              ;; Look for rfc2822-style: sequences of atoms, quoted
              ;; strings, specials, whitespace.  (Specials mustn't be
              ;; encoded.)
@@ -329,137 +422,195 @@ Dynamically bind `rfc2047-encoding-type' to change that."
                (cond
                 ((not (char-after)))   ; eob
                 ;; else token start
-                ((eq ?\" (char-syntax (char-after)))
+                ((eq ?\" (setq csyntax (char-syntax (char-after))))
                  ;; Quoted word.
                  (forward-sexp)
                  (setq end (point))
                  ;; Does it need encoding?
                  (goto-char start)
-                 (skip-chars-forward "\000-\177" end)
-                 (if (= end (point))
-                     (setq last-encoded  nil)
-                   ;; It needs encoding.  Strip the quotes first,
-                   ;; since encoded words can't occur in quotes.
-                   (goto-char end)
-                   (delete-backward-char 1)
-                   (goto-char start)
-                   (delete-char 1)
-                   (when last-encoded
-                     ;; There was a preceding quoted word.  We need
-                     ;; to include any separating whitespace in this
-                     ;; word to avoid it getting lost.
-                     (skip-chars-backward " \t")
-                     ;; A space is needed between the encoded words.
-                     (insert ? )
-                     (setq start (point)
-                           end (1+ end)))
-                   ;; Adjust the end position for the deleted quotes.
-                   (rfc2047-encode start (- end 2))
-                   (setq last-encoded t))) ; record that it was encoded
-                ((eq ?. (char-syntax (char-after)))
+                 (if (re-search-forward encodable-regexp end 'move)
+                     ;; It needs encoding.  Strip the quotes first,
+                     ;; since encoded words can't occur in quotes.
+                     (progn
+                       (goto-char end)
+                       (delete-char -1)
+                       (goto-char start)
+                       (delete-char 1)
+                       (when last-encoded
+                         ;; There was a preceding quoted word.  We need
+                         ;; to include any separating whitespace in this
+                         ;; word to avoid it getting lost.
+                         (skip-chars-backward " \t")
+                         ;; A space is needed between the encoded words.
+                         (insert ? )
+                         (setq start (point)
+                               end (1+ end)))
+                       ;; Adjust the end position for the deleted quotes.
+                       (rfc2047-encode start (- end 2))
+                       (setq last-encoded t)) ; record that it was encoded
+                   (setq last-encoded  nil)))
+                ((eq ?. csyntax)
                  ;; Skip other delimiters, but record that they've
                  ;; potentially separated quoted words.
                  (forward-char)
                  (setq last-encoded nil))
+                ((eq ?\) csyntax)
+                 (error "Unbalanced parentheses"))
+                ((eq ?\( csyntax)
+                 ;; Look for the end of parentheses.
+                 (forward-list)
+                 ;; Encode text as an unstructured field.
+                 (let ((rfc2047-encoding-type 'mime))
+                   (rfc2047-encode-region (1+ start) (1- (point))))
+                 (skip-chars-forward ")"))
                 (t                 ; normal token/whitespace sequence
                  ;; Find the end.
+                 ;; Skip one ASCII word, or encode continuous words
+                 ;; in which all those contain non-ASCII characters.
+                 (setq end nil)
+                 (while (not (or end (eobp)))
+                   (when (looking-at "[\000-\177]+")
+                     (setq begin (point)
+                           end (match-end 0))
+                     (when (progn
+                             (while (and (or (re-search-forward
+                                              "[ \t\n]\\|\\Sw" end 'move)
+                                             (setq end nil))
+                                         (eq ?\\ (char-syntax (char-before))))
+                               ;; Skip backslash-quoted characters.
+                               (forward-char))
+                             end)
+                       (setq end (match-beginning 0))
+                       (if rfc2047-encode-encoded-words
+                           (progn
+                             (goto-char begin)
+                             (when (search-forward "=?" end 'move)
+                               (goto-char (match-beginning 0))
+                               (setq end nil)))
+                         (goto-char end))))
+                   ;; Where the value nil of `end' means there may be
+                   ;; text to have to be encoded following the point.
+                   ;; Otherwise, the point reached to the end of ASCII
+                   ;; words separated by whitespace or a special char.
+                   (unless end
+                     (when (looking-at encodable-regexp)
+                       (goto-char (setq begin (match-end 0)))
+                       (while (and (looking-at "[ \t\n]+\\([^ \t\n]+\\)")
+                                   (setq end (match-end 0))
+                                   (progn
+                                     (while (re-search-forward
+                                             encodable-regexp end t))
+                                     (< begin (point)))
+                                   (goto-char begin)
+                                   (or (not (re-search-forward "\\Sw" end t))
+                                       (progn
+                                         (goto-char (match-beginning 0))
+                                         nil)))
+                         (goto-char end))
+                       (when (looking-at "[^ \t\n]+")
+                         (setq end (match-end 0))
+                         (if (re-search-forward "\\Sw+" end t)
+                             ;; There are special characters better
+                             ;; to be encoded so that MTAs may parse
+                             ;; them safely.
+                             (cond ((= end (point)))
+                                   ((looking-at (concat "\\sw*\\("
+                                                        encodable-regexp
+                                                        "\\)"))
+                                    (setq end nil))
+                                   (t
+                                    (goto-char (1- (match-end 0)))
+                                    (unless (= (point) (match-beginning 0))
+                                      ;; Separate encodable text and
+                                      ;; delimiter.
+                                      (insert " "))))
+                           (goto-char end)
+                           (skip-chars-forward " \t\n")
+                           (if (and (looking-at "[^ \t\n]+")
+                                    (string-match encodable-regexp
+                                                  (match-string 0)))
+                               (setq end nil)
+                             (goto-char end)))))))
                  (skip-chars-backward " \t\n")
-                 (if (and (eq (char-before) ?\()
-                          ;; Look for the end of parentheses.
-                          (let ((string (buffer-substring (point)
-                                                          (point-max)))
-                                (default-major-mode 'fundamental-mode))
-                            ;; Use `standard-syntax-table'.
-                            (with-temp-buffer
-                              (insert "(" string)
-                              (goto-char (point-min))
-                              (condition-case nil
-                                  (progn
-                                    (forward-list 1)
-                                    (setq end (- (point) 3)))
-                                (error nil)))))
-                     ;; Encode text as an unstructured field.
-                     (let ((rfc2047-encoding-type 'mime))
-                       (rfc2047-encode-region start (+ (point) end))
-                       (forward-char))
-                   ;; Skip one ASCII word, or encode continuous words
-                   ;; in which all those contain non-ASCII characters.
-                   (skip-chars-forward " \t\n")
-                   (setq end nil)
-                   (while (not end)
-                     (when (looking-at "[\000-\177]+")
-                       (setq end (match-end 0))
-                       (if (re-search-forward "[ \t\n]\\|\\Sw" end t)
-                           (goto-char (match-beginning 0))
-                         (goto-char end)
-                         (setq end nil)))
-                     (unless end
-                       (setq end t)
-                       (when (looking-at "[^\000-\177]+")
-                         (goto-char (match-end 0))
-                         (while (and (looking-at "[ \t\n]+\\([^ \t\n]+\\)")
-                                     (setq end (match-end 0))
-                                     (string-match "[^\000-\177]"
-                                                   (match-string 1)))
-                           (goto-char end))
-                         (when (looking-at "[^ \t\n]+")
-                           (setq end (match-end 0))
-                           (if (re-search-forward "\\Sw+" end t)
-                               ;; There are special characters better
-                               ;; to be encoded so that MTAs may parse
-                               ;; them safely.
-                               (cond ((= end (point)))
-                                     ((looking-at "[^\000-\177]")
-                                      (setq end nil))
-                                     (t
-                                      (goto-char (1- (match-end 0)))
-                                      (unless (= (point) (match-beginning 0))
-                                        (insert " "))))
-                             (goto-char end)
-                             (skip-chars-forward " \t\n")
-                             (if (and (looking-at "[^ \t\n]+")
-                                      (string-match "[^\000-\177]"
-                                                    (match-string 0)))
-                                 (setq end nil)
-                               (goto-char end)))))))
-                   (skip-chars-backward " \t\n")
-                   (setq end (point))
-                   (goto-char start)
-                   (skip-chars-forward "\000-\177" end)
-                   (if (= end (point))
-                       (setq last-encoded nil)
-                     (rfc2047-encode start end)
-                     (setq last-encoded t))))))
+                 (setq end (point))
+                 (goto-char start)
+                 (if (re-search-forward encodable-regexp end 'move)
+                     (progn
+                       (unless (memq (char-before start) '(nil ?\t ? ))
+                         (if (progn
+                               (goto-char start)
+                               (skip-chars-backward "^ \t\n")
+                               (and (looking-at "\\Sw+")
+                                    (= (match-end 0) start)))
+                             ;; Also encode bogus delimiters.
+                             (setq start (point))
+                           ;; Separate encodable text and delimiter.
+                           (goto-char start)
+                           (insert " ")
+                           (setq start (1+ start)
+                                 end (1+ end))))
+                       (rfc2047-encode start end)
+                       (setq last-encoded t))
+                   (setq last-encoded nil)))))
            (error
-            (error "Invalid data for rfc2047 encoding: %s"
-                   (buffer-substring b e)))))))
-    (rfc2047-fold-region b (point))))
+            (if (or debug-on-quit debug-on-error)
+                (signal (car err) (cdr err))
+              (error "Invalid data for rfc2047 encoding: %s"
+                     (mm-replace-in-string orig-text "[ \t\n]+" " "))))))))
+    (unless dont-fold
+      (rfc2047-fold-region b (point)))
+    (goto-char (point-max))))
 
-(defun rfc2047-encode-string (string)
+(defun rfc2047-encode-string (string &optional dont-fold)
   "Encode words in STRING.
 By default, the string is treated as containing addresses (see
 `rfc2047-encoding-type')."
-  (with-temp-buffer
+  (mm-with-multibyte-buffer
     (insert string)
-    (rfc2047-encode-region (point-min) (point-max))
+    (rfc2047-encode-region (point-min) (point-max) dont-fold)
     (buffer-string)))
 
-(defun rfc2047-encode-1 (column string cs encoder start space &optional eword)
+;; From RFC 2047:
+;; 2. Syntax of encoded-words
+;;    [...]
+;;    While there is no limit to the length of a multiple-line header
+;;    field, each line of a header field that contains one or more
+;;    'encoded-word's is limited to 76 characters.
+;;
+;; In `rfc2047-encode-parameter' it is bound to nil, so don't defconst it.
+(defvar rfc2047-encode-max-chars 76
+  "Maximum characters of each header line that contain encoded-words.
+According to RFC 2047, it is 76.  If it is nil, encoded-words
+will not be folded.  Too small value may cause an error.  You
+should not change this value.")
+
+(defun rfc2047-encode-1 (column string cs encoder start crest tail
+                               &optional eword)
   "Subroutine used by `rfc2047-encode'."
   (cond ((string-equal string "")
         (or eword ""))
-       ((>= column 76)
-        (when (and eword
-                   (string-match "\n[ \t]+\\'" eword))
-          ;; Reomove a superfluous empty line.
-          (setq eword (substring eword 0 (match-beginning 0))))
-        (rfc2047-encode-1 (length space) string cs encoder start " "
-                          (concat eword "\n" space)))
+       ((not rfc2047-encode-max-chars)
+        (concat start
+                (funcall encoder (if cs
+                                     (mm-encode-coding-string string cs)
+                                   string))
+                "?="))
+       ((>= column rfc2047-encode-max-chars)
+        (when eword
+          (cond ((string-match "\n[ \t]+\\'" eword)
+                 ;; Remove a superfluous empty line.
+                 (setq eword (substring eword 0 (match-beginning 0))))
+                ((string-match "(+\\'" eword)
+                 ;; Break the line before the open parenthesis.
+                 (setq crest (concat crest (match-string 0 eword))
+                       eword (substring eword 0 (match-beginning 0))))))
+        (rfc2047-encode-1 (length crest) string cs encoder start " " tail
+                          (concat eword "\n" crest)))
        (t
         (let ((index 0)
               (limit (1- (length string)))
               (prev "")
-              next)
+              next len)
           (while (and prev
                       (<= index limit))
             (setq next (concat start
@@ -469,28 +620,51 @@ By default, the string is treated as containing addresses (see
                                              (substring string 0 (1+ index))
                                              cs)
                                           (substring string 0 (1+ index))))
-                               "?="))
-            (if (<= (+ column (length next)) 76)
-                (setq prev next
-                      index (1+ index))
-              (setq next prev
-                    prev nil)))
-          (setq eword (concat eword next))
+                               "?=")
+                  len (+ column (length next)))
+            (if (> len rfc2047-encode-max-chars)
+                (setq next prev
+                      prev nil)
+              (if (or (< index limit)
+                      (<= (+ len (or (string-match "\n" tail)
+                                     (length tail)))
+                          rfc2047-encode-max-chars))
+                  (setq prev next
+                        index (1+ index))
+                (if (string-match "\\`)+" tail)
+                    ;; Break the line after the close parenthesis.
+                    (setq tail (concat (substring tail 0 (match-end 0))
+                                       "\n "
+                                       (substring tail (match-end 0)))
+                          prev next
+                          index (1+ index))
+                  (setq next prev
+                        prev nil)))))
           (if (> index limit)
-              eword
+              (concat eword next tail)
+            (if (= 0 index)
+                (if (and eword
+                         (string-match "(+\\'" eword))
+                    (setq crest (concat crest (match-string 0 eword))
+                          eword (substring eword 0 (match-beginning 0)))
+                  (setq eword (concat eword next)))
+              (setq crest " "
+                    eword (concat eword next)))
             (when (string-match "\n[ \t]+\\'" eword)
-              ;; Reomove a superfluous empty line.
+              ;; Remove a superfluous empty line.
               (setq eword (substring eword 0 (match-beginning 0))))
-            (rfc2047-encode-1 (length space) (substring string index)
-                              cs encoder start " "
-                              (concat eword "\n" space)))))))
+            (rfc2047-encode-1 (length crest) (substring string index)
+                              cs encoder start " " tail
+                              (concat eword "\n" crest)))))))
 
 (defun rfc2047-encode (b e)
   "Encode the word(s) in the region B to E.
-By default, the region is treated as containing addresses (see
-`rfc2047-encoding-type')."
+Point moves to the end of the region."
   (let ((mime-charset (or (mm-find-mime-charset-region b e) (list 'us-ascii)))
-       cs encoding space eword)
+       cs encoding tail crest eword)
+    ;; Use utf-8 as a last resort if determining charset of text fails.
+    (if (memq nil mime-charset)
+       (setq mime-charset (list 'utf-8)))
     (cond ((> (length mime-charset) 1)
           (error "Can't rfc2047-encode `%s'"
                  (buffer-substring-no-properties b e)))
@@ -511,9 +685,19 @@ By default, the region is treated as containing addresses (see
                           'B
                         'Q)))
             (widen)
+            (goto-char e)
+            (skip-chars-forward "^ \t\n")
+            ;; `tail' may contain a close parenthesis.
+            (setq tail (buffer-substring-no-properties e (point)))
+            (goto-char b)
+            (setq b (point-marker)
+                  e (set-marker (make-marker) e))
+            (rfc2047-fold-region (point-at-bol) b)
             (goto-char b)
+            (skip-chars-backward "^ \t\n")
             (unless (= 0 (skip-chars-backward " \t"))
-              (setq space (buffer-substring-no-properties (point) b)))
+              ;; `crest' may contain whitespace and an open parenthesis.
+              (setq crest (buffer-substring-no-properties (point) b)))
             (setq eword (rfc2047-encode-1
                          (- b (point-at-bol))
                          (mm-replace-in-string
@@ -525,13 +709,21 @@ By default, the region is treated as containing addresses (see
                              'identity)
                          (concat "=?" (downcase (symbol-name mime-charset))
                                  "?" (upcase (symbol-name encoding)) "?")
-                         (or space " ")))
+                         (or crest " ")
+                         tail))
             (delete-region (if (eq (aref eword 0) ?\n)
-                               (point)
+                               (if (bolp)
+                                   ;; The line was folded before encoding.
+                                   (1- (point))
+                                 (point))
                              (goto-char b))
-                           e)
+                           (+ e (length tail)))
+            ;; `eword' contains `crest' and `tail'.
             (insert eword)
-            (unless (or (eolp)
+            (set-marker b nil)
+            (set-marker e nil)
+            (unless (or (/= 0 (length tail))
+                        (eobp)
                         (looking-at "[ \t\n)]"))
               (insert " "))))
          (t
@@ -602,9 +794,10 @@ By default, the region is treated as containing addresses (see
        (goto-char (or break qword-break))
        (setq break nil
              qword-break nil)
-         (if (looking-at "[ \t]")
-             (insert ?\n)
-           (insert "\n "))
+       (if (or (> 0 (skip-chars-backward " \t"))
+               (looking-at "[ \t]"))
+           (insert ?\n)
+         (insert "\n "))
        (setq bol (1- (point)))
        ;; Don't break before the first non-LWSP characters.
        (skip-chars-forward " \t")
@@ -643,6 +836,8 @@ By default, the region is treated as containing addresses (see
   "Base64-encode the header contained in STRING."
   (base64-encode-string string t))
 
+(autoload 'quoted-printable-encode-region "qp")
+
 (defun rfc2047-q-encode-string (string)
   "Quoted-printable-encode the header in STRING."
   (mm-with-unibyte-buffer
@@ -661,14 +856,125 @@ By default, the region is treated as containing addresses (see
     (subst-char-in-region (point-min) (point-max) ?  ?_)
     (buffer-string)))
 
+(defun rfc2047-encode-parameter (param value)
+  "Return and PARAM=VALUE string encoded in the RFC2047-like style.
+This is a substitution for the `rfc2231-encode-string' function, that
+is the standard but many mailers don't support it."
+  (let ((rfc2047-encoding-type 'mime)
+       (rfc2047-encode-max-chars nil))
+    (rfc2045-encode-string param (rfc2047-encode-string value t))))
+
 ;;;
 ;;; Functions for decoding RFC2047 messages
 ;;;
 
-(eval-and-compile
-  (defconst rfc2047-encoded-word-regexp
-    "=\\?\\([^][\000-\040()<>@,\;:*\\\"/?.=]+\\)\\(?:\\*[^?]+\\)?\
-\\?\\(B\\|Q\\)\\?\\([!->@-~ ]*\\)\\?="))
+(defvar rfc2047-quote-decoded-words-containing-tspecials nil
+  "If non-nil, quote decoded words containing special characters.")
+
+(defvar rfc2047-allow-incomplete-encoded-text t
+  "*Non-nil means allow incomplete encoded-text in successive encoded-words.
+Dividing of encoded-text in the place other than character boundaries
+violates RFC2047 section 5, while we have a capability to decode it.
+If it is non-nil, the decoder will decode B- or Q-encoding in each
+encoded-word, concatenate them, and decode it by charset.  Otherwise,
+the decoder will fully decode each encoded-word before concatenating
+them.")
+
+(defun rfc2047-strip-backslashes-in-quoted-strings ()
+  "Strip backslashes in quoted strings.  `\\\"' remains."
+  (goto-char (point-min))
+  (let (beg)
+    (with-syntax-table (standard-syntax-table)
+      (while (search-forward "\"" nil t)
+       (unless (eq (char-before) ?\\)
+         (setq beg (match-end 0))
+         (goto-char (match-beginning 0))
+         (condition-case nil
+             (progn
+               (forward-sexp)
+               (save-restriction
+                 (narrow-to-region beg (1- (point)))
+                 (goto-char beg)
+                 (while (search-forward "\\" nil 'move)
+                   (unless (memq (char-after) '(?\"))
+                     (delete-char -1))
+                   (forward-char)))
+               (forward-char))
+           (error
+            (goto-char beg))))))))
+
+(defun rfc2047-charset-to-coding-system (charset &optional allow-override)
+  "Return coding-system corresponding to MIME CHARSET.
+If your Emacs implementation can't decode CHARSET, return nil.
+
+If allow-override is given, use `mm-charset-override-alist' to
+map undesired charset names to their replacement.  This should
+only be used for decoding, not for encoding."
+  (when (stringp charset)
+    (setq charset (intern (downcase charset))))
+  (when (or (not charset)
+           (eq 'gnus-all mail-parse-ignored-charsets)
+           (memq 'gnus-all mail-parse-ignored-charsets)
+           (memq charset mail-parse-ignored-charsets))
+    (setq charset mail-parse-charset))
+  (let ((cs (mm-charset-to-coding-system charset nil allow-override)))
+    (cond ((eq cs 'ascii)
+          (setq cs (or (mm-charset-to-coding-system mail-parse-charset)
+                       'raw-text)))
+         ((mm-coding-system-p cs))
+         ((and charset
+               (listp mail-parse-ignored-charsets)
+               (memq 'gnus-unknown mail-parse-ignored-charsets))
+          (setq cs (mm-charset-to-coding-system mail-parse-charset))))
+    (if (eq cs 'ascii)
+       'raw-text
+      cs)))
+
+(autoload 'quoted-printable-decode-string "qp")
+
+(defun rfc2047-decode-encoded-words (words)
+  "Decode successive encoded-words in WORDS and return a decoded string.
+Each element of WORDS looks like (CHARSET ENCODING ENCODED-TEXT
+ENCODED-WORD)."
+  (let (word charset cs encoding text rest)
+    (while words
+      (setq word (pop words))
+      (if (and (setq cs (rfc2047-charset-to-coding-system
+                        (setq charset (car word)) t))
+              (condition-case code
+                  (cond ((char-equal ?B (nth 1 word))
+                         (setq text (base64-decode-string
+                                     (rfc2047-pad-base64 (nth 2 word)))))
+                        ((char-equal ?Q (nth 1 word))
+                         (setq text (quoted-printable-decode-string
+                                     (mm-subst-char-in-string
+                                      ?_ ?  (nth 2 word) t)))))
+                (error
+                 (message "%s" (error-message-string code))
+                 nil)))
+         (if (and rfc2047-allow-incomplete-encoded-text
+                  (eq cs (caar rest)))
+             ;; Concatenate text of which the charset is the same.
+             (setcdr (car rest) (concat (cdar rest) text))
+           (push (cons cs text) rest))
+       ;; Don't decode encoded-word.
+       (push (cons nil (nth 3 word)) rest)))
+    (while rest
+      (setq words (concat
+                  (or (and (setq cs (caar rest))
+                           (condition-case code
+                               (mm-decode-coding-string (cdar rest) cs)
+                             (error
+                              (message "%s" (error-message-string code))
+                              nil)))
+                      (concat (when (cdr rest) " ")
+                              (cdar rest)
+                              (when (and words
+                                         (not (eq (string-to-char words) ? )))
+                                " ")))
+                  words)
+           rest (cdr rest)))
+    words))
 
 ;; Fixme: This should decode in place, not cons intermediate strings.
 ;; Also check whether it needs to worry about delimiting fields like
@@ -680,38 +986,102 @@ By default, the region is treated as containing addresses (see
 ;; and worthwhile (is it more correct or not?), e.g. something like
 ;; `=?iso-8859-1?q?foo?=@'.
 
-(defun rfc2047-decode-region (start end)
-  "Decode MIME-encoded words in region between START and END."
+(defun rfc2047-decode-region (start end &optional address-mime)
+  "Decode MIME-encoded words in region between START and END.
+If ADDRESS-MIME is non-nil, strip backslashes which precede characters
+other than `\"' and `\\' in quoted strings."
   (interactive "r")
   (let ((case-fold-search t)
-       b e)
+       (eword-regexp
+        (if rfc2047-allow-irregular-q-encoded-words
+            (eval-when-compile
+              (concat "[\n\t ]*\\(" rfc2047-encoded-word-regexp-loose "\\)"))
+          (eval-when-compile
+            (concat "[\n\t ]*\\(" rfc2047-encoded-word-regexp "\\)"))))
+       b e match words)
     (save-excursion
       (save-restriction
        (narrow-to-region start end)
-       (goto-char (point-min))
-       ;; Remove whitespace between encoded words.
-       (while (re-search-forward
-               (eval-when-compile
-                 (concat "\\(" rfc2047-encoded-word-regexp "\\)"
-                         "\\(\n?[ \t]\\)+"
-                         "\\(" rfc2047-encoded-word-regexp "\\)"))
-               nil t)
-         (delete-region (goto-char (match-end 1)) (match-beginning 6)))
-       ;; Decode the encoded words.
-       (setq b (goto-char (point-min)))
-       (while (re-search-forward rfc2047-encoded-word-regexp nil t)
-         (setq e (match-beginning 0))
-         (insert (rfc2047-parse-and-decode
-                  (prog1
-                      (match-string 0)
-                    (delete-region (match-beginning 0) (match-end 0)))))
-         ;; Remove newlines between decoded words, though such things
-         ;; essentially must not be there.
+       (when address-mime
+         (rfc2047-strip-backslashes-in-quoted-strings))
+       (goto-char (setq b start))
+       ;; Look for the encoded-words.
+       (while (setq match (re-search-forward eword-regexp nil t))
+         (setq e (match-beginning 1)
+               end (match-end 0)
+               words nil)
+         (while match
+           (push (list (match-string 2) ;; charset
+                       (char-after (match-beginning 3)) ;; encoding
+                       (substring (match-string 3) 2) ;; encoded-text
+                       (match-string 1)) ;; encoded-word
+                 words)
+           ;; Look for the subsequent encoded-words.
+           (when (setq match (looking-at eword-regexp))
+             (goto-char (setq end (match-end 0)))))
+         ;; Replace the encoded-words with the decoded one.
+         (delete-region e end)
+         (insert (rfc2047-decode-encoded-words (nreverse words)))
          (save-restriction
            (narrow-to-region e (point))
            (goto-char e)
+           ;; Remove newlines between decoded words, though such
+           ;; things essentially must not be there.
            (while (re-search-forward "[\n\r]+" nil t)
              (replace-match " "))
+           (setq end (point-max))
+           ;; Quote decoded words if there are special characters
+           ;; which might violate RFC2822.
+           (when (and rfc2047-quote-decoded-words-containing-tspecials
+                      (let ((regexp (car (rassq
+                                          'address-mime
+                                          rfc2047-header-encoding-alist))))
+                        (when regexp
+                          (save-restriction
+                            (widen)
+                            (and
+                             ;; Don't quote words if already quoted.
+                             (not (and (eq (char-before e) ?\")
+                                       (eq (char-after end) ?\")))
+                             (progn
+                               (beginning-of-line)
+                               (while (and (memq (char-after) '(?  ?\t))
+                                           (zerop (forward-line -1))))
+                               (looking-at regexp)))))))
+             (let (quoted)
+               (goto-char e)
+               (skip-chars-forward " \t")
+               (setq start (point))
+               (setq quoted (eq (char-after) ?\"))
+               (goto-char (point-max))
+               (skip-chars-backward " \t" start)
+               (if (setq quoted (and quoted
+                                     (> (point) (1+ start))
+                                     (eq (char-before) ?\")))
+                   (progn
+                     (backward-char)
+                     (setq start (1+ start)
+                           end (point-marker)))
+                 (setq end (point-marker)))
+               (goto-char start)
+               (while (search-forward "\"" end t)
+                 (when (prog2
+                           (backward-char)
+                           (zerop (% (skip-chars-backward "\\\\") 2))
+                         (goto-char (match-beginning 0)))
+                   (insert "\\"))
+                 (forward-char))
+               (when (and (not quoted)
+                          (progn
+                            (goto-char start)
+                            (re-search-forward
+                             (concat "[" ietf-drums-tspecials "]")
+                             end t)))
+                 (goto-char start)
+                 (insert "\"")
+                 (goto-char end)
+                 (insert "\""))
+               (set-marker end nil)))
            (goto-char (point-max)))
          (when (and (mm-multibyte-p)
                     mail-parse-charset
@@ -725,25 +1095,41 @@ By default, the region is treated as containing addresses (see
                   (not (eq mail-parse-charset 'gnus-decoded)))
          (mm-decode-coding-region b (point-max) mail-parse-charset))))))
 
-(defun rfc2047-decode-string (string)
-  "Decode the quoted-printable-encoded STRING and return the results."
-  (let ((m (mm-multibyte-p)))
+(defun rfc2047-decode-address-region (start end)
+  "Decode MIME-encoded words in region between START and END.
+Backslashes which precede characters other than `\"' and `\\' in quoted
+strings are stripped."
+  (rfc2047-decode-region start end t))
+
+(defun rfc2047-decode-string (string &optional address-mime)
+  "Decode MIME-encoded STRING and return the result.
+If ADDRESS-MIME is non-nil, strip backslashes which precede characters
+other than `\"' and `\\' in quoted strings."
+  ;; (let ((m (mm-multibyte-p)))
     (if (string-match "=\\?" string)
        (with-temp-buffer
-         ;; Fixme: This logic is wrong, but seems to be required by
-         ;; Gnus summary buffer generation.  The value of `m' depends
-         ;; on the current buffer, not global multibyteness or that
-         ;; of the string.  Also the string returned should always be
-         ;; multibyte in a multibyte session, i.e. the buffer should
-         ;; be multibyte before `buffer-string' is called.
-         (when m
-           (mm-enable-multibyte))
+          ;; We used to only call mm-enable-multibyte if `m' is non-nil,
+          ;; but this can't be the right criterion.  Don't just revert this
+          ;; change if it encounters a bug.  Please help me fix it
+          ;; right instead.  --Stef
+          ;; The string returned should always be multibyte in a multibyte
+         ;; session, i.e. the buffer should be multibyte before
+         ;; `buffer-string' is called.
+          (mm-enable-multibyte)
          (insert string)
          (inline
-           (rfc2047-decode-region (point-min) (point-max)))
+           (rfc2047-decode-region (point-min) (point-max) address-mime))
          (buffer-string))
+      (when address-mime
+       (setq string
+             (with-temp-buffer
+               (when (mm-multibyte-string-p string)
+                 (mm-enable-multibyte))
+               (insert string)
+               (rfc2047-strip-backslashes-in-quoted-strings)
+               (buffer-string))))
       ;; Fixme: As above, `m' here is inappropriate.
-      (if (and m
+      (if (and ;; m
               mail-parse-charset
               (not (eq mail-parse-charset 'us-ascii))
               (not (eq mail-parse-charset 'gnus-decoded)))
@@ -759,24 +1145,15 @@ By default, the region is treated as containing addresses (see
          (if (and (fboundp 'detect-coding-string)
                   ;; string is purely ASCII
                   (eq (detect-coding-string string t) 'undecided))
-             string
-           (mm-decode-coding-string string mail-parse-charset))
-       (mm-string-as-multibyte string)))))
-
-(defun rfc2047-parse-and-decode (word)
-  "Decode WORD and return it if it is an encoded word.
-Return WORD if it is not not an encoded word or if the charset isn't
-decodable."
-  (if (not (string-match rfc2047-encoded-word-regexp word))
-      word
-    (or
-     (condition-case nil
-        (rfc2047-decode
-         (match-string 1 word)
-         (string-to-char (match-string 2 word))
-         (match-string 3 word))
-       (error word))
-     word)))                           ; un-decodable
+              string
+            (mm-decode-coding-string string mail-parse-charset))
+        (mm-string-to-multibyte string)))) ;; )
+
+(defun rfc2047-decode-address-string (string)
+  "Decode MIME-encoded STRING and return the result.
+Backslashes which precede characters other than `\"' and `\\' in quoted
+strings are stripped."
+  (rfc2047-decode-string string t))
 
 (defun rfc2047-pad-base64 (string)
   "Pad STRING to quartets."
@@ -793,38 +1170,6 @@ decodable."
       (2 (concat string "=="))
       (3 (concat string "=")))))
 
-(defun rfc2047-decode (charset encoding string)
-  "Decode STRING from the given MIME CHARSET in the given ENCODING.
-Valid ENCODINGs are the characters \"B\" and \"Q\".
-If your Emacs implementation can't decode CHARSET, return nil."
-  (if (stringp charset)
-      (setq charset (intern (downcase charset))))
-  (if (or (not charset)
-         (eq 'gnus-all mail-parse-ignored-charsets)
-         (memq 'gnus-all mail-parse-ignored-charsets)
-         (memq charset mail-parse-ignored-charsets))
-      (setq charset mail-parse-charset))
-  (let ((cs (mm-charset-to-coding-system charset)))
-    (if (and (not cs) charset
-            (listp mail-parse-ignored-charsets)
-            (memq 'gnus-unknown mail-parse-ignored-charsets))
-       (setq cs (mm-charset-to-coding-system mail-parse-charset)))
-    (when cs
-      (when (and (eq cs 'ascii)
-                mail-parse-charset)
-       (setq cs mail-parse-charset))
-      (mm-decode-coding-string
-       (cond
-       ((char-equal ?B encoding)
-        (base64-decode-string
-         (rfc2047-pad-base64 string)))
-       ((char-equal ?Q encoding)
-        (quoted-printable-decode-string
-         (mm-subst-char-in-string ?_ ? string t)))
-       (t (error "Invalid encoding: %c" encoding)))
-       cs))))
-
 (provide 'rfc2047)
 
-;;; arch-tag: a07fe3d4-22b5-4c4a-bd89-b1f82d5d36f6
 ;;; rfc2047.el ends here