(rfc2047-encoded-word-regexp): Support RFC 2231

[gnus] / lisp / rfc2047.el

diff --git a/lisp/rfc2047.el b/lisp/rfc2047.el
index 1ba47df..ebd8a4a 100644 (file)
--- a/lisp/rfc2047.el
+++ b/lisp/rfc2047.el
@@ -97,6 +97,25 @@ quoted-printable and base64 respectively.")
 ;;; Functions for encoding RFC2047 messages
 ;;;
 
+(defun rfc2047-qp-or-base64 ()
+  "Return the type with which to encode the buffer.
+This is either `base64' or `quoted-printable'."
+  (save-excursion
+    (let ((limit (min (point-max) (+ 2000 (point-min))))
+         (n8bit 0))
+      (goto-char (point-min))
+      (skip-chars-forward "\x20-\x7f\r\n\t" limit)
+      (while (< (point) limit)
+       (incf n8bit)
+       (forward-char 1)
+       (skip-chars-forward "\x20-\x7f\r\n\t" limit))
+      (if (or (< (* 6 n8bit) (- limit (point-min)))
+             ;; Don't base64, say, a short line with a single
+             ;; non-ASCII char when splitting parts by charset.
+             (= n8bit 1))
+         'quoted-printable
+       'base64))))
+
 (defun rfc2047-narrow-to-field ()
   "Narrow the buffer to the header on the current line."
   (beginning-of-line)
@@ -382,7 +401,7 @@ By default, the region is treated as containing addresses (see
                       ;; encoding, choose the one that's shorter.
                       (save-restriction
                         (narrow-to-region b e)
-                        (if (eq (mm-qp-or-base64) 'base64)
+                        (if (eq (rfc2047-qp-or-base64) 'base64)
                             'B
                           'Q))))
         (start (concat
@@ -588,8 +607,8 @@ By default, the region is treated as containing addresses (see
 
 (eval-and-compile
   (defconst rfc2047-encoded-word-regexp
-    "=\\?\\([^][\000-\040()<>@,\;:\\\"/?.=]+\\)\\?\\(B\\|Q\\)\
-\\?\\([!->@-~ +]*\\)\\?="))
+    "=\\?\\([^][\000-\040()<>@,\;:*\\\"/?.=]+\\)(?:\\*[^?]+\\)?\
+\\?\\(B\\|Q\\)\\?\\([!->@-~ +]*\\)\\?="))
 
 ;; Fixme: This should decode in place, not cons intermediate strings.
 ;; Also check whether it needs to worry about delimiting fields like