Importing pgnus-0.30.

[elisp/gnus.git-] / lisp / rfc2231.el

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+;;; rfc2231.el --- Functions for decoding rfc2231 headers
+;; Copyright (C) 1998 Free Software Foundation, Inc.
+
+;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
+;; This file is part of GNU Emacs.
+
+;; 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.
+
+;; 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
+;; 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.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'drums)
+
+(defun rfc2231-get-value (ct attribute)
+  "Return the value of ATTRIBUTE from CT."
+  (cdr (assq attribute (cdr ct))))
+
+(defun rfc2231-parse-string (string)
+  "Parse STRING and return a list.
+The list will be on the form
+ `(name (attribute . value) (attribute . value)...)"
+  (with-temp-buffer
+    (let ((ttoken (drums-token-to-list drums-text-token))
+         (stoken (drums-token-to-list drums-tspecials))
+         (ntoken (drums-token-to-list "0-9"))
+         (prev-value "")
+         display-name mailbox c display-string parameters
+         attribute value type subtype number encoded
+         prev-attribute)
+      (drums-init (mail-header-remove-whitespace
+                  (mail-header-remove-comments string)))
+      (let ((table (copy-syntax-table drums-syntax-table)))
+       (modify-syntax-entry ?\' "w" table)
+       (set-syntax-table table))
+      (setq c (following-char))
+      (when (and (memq c ttoken)
+                (not (memq c stoken)))
+       (setq type (downcase (buffer-substring
+                             (point) (progn (forward-sexp 1) (point)))))
+       ;; Do the params
+       (while (not (eobp))
+         (setq c (following-char))
+         (unless (eq c ?\;)
+           (error "Invalid header: %s" string))
+         (forward-char 1)
+         (setq c (following-char))
+         (if (and (memq c ttoken)
+                  (not (memq c stoken)))
+             (setq attribute
+                   (intern
+                    (downcase
+                     (buffer-substring
+                      (point) (progn (forward-sexp 1) (point))))))
+           (error "Invalid header: %s" string))
+         (setq c (following-char))
+         (setq encoded nil)
+         (when (eq c ?*)
+           (forward-char 1)
+           (setq c (following-char))
+           (when (memq c ntoken)
+             (setq number
+                   (string-to-number
+                    (buffer-substring
+                     (point) (progn (forward-sexp 1) (point)))))
+             (setq c (following-char))
+             (when (eq c ?*)
+               (setq encoded t)
+               (forward-char 1)
+               (setq c (following-char)))))
+         ;; See if we have any previous continuations.
+         (when (and prev-attribute
+                    (not (eq prev-attribute attribute)))
+           (push (cons prev-attribute prev-value) parameters)
+           (setq prev-attribute nil
+                 prev-value ""))
+         (unless (eq c ?=)
+           (error "Invalid header: %s" string))
+         (forward-char 1)
+         (setq c (following-char))
+         (cond
+          ((eq c ?\")
+           (setq value
+                 (buffer-substring (1+ (point))
+                                   (progn (forward-sexp 1) (1- (point))))))
+          ((and (memq c ttoken)
+                (not (memq c stoken)))
+           (setq value (buffer-substring
+                        (point) (progn (forward-sexp 1) (point)))))
+          (t
+           (error "Invalid header: %s" string)))
+         (when encoded
+           (setq value (rfc2231-decode-encoded-string value)))
+         (if number
+             (setq prev-attribute attribute
+                   prev-value (concat prev-value value))
+           (push (cons attribute value) parameters)))
+
+       ;; Take care of any final continuations.
+       (when prev-attribute
+         (push (cons prev-attribute prev-value) parameters))
+
+       `(,type ,@(nreverse parameters))))))
+
+(defun rfc2231-decode-encoded-string (string)
+  "Decode an RFC2231-encoded string.
+These look like \"us-ascii'en-us'This%20is%20%2A%2A%2Afun%2A%2A%2A\"."
+  (with-temp-buffer
+    (let ((elems (split-string string "'")))
+      ;; The encoded string may contain zero to two single-quote
+      ;; marks.  This should give us the encoded word stripped
+      ;; of any preceding values.
+      (insert (car (last elems)))
+      (goto-char (point-min))
+      (while (search-forward "%" nil t)
+       (insert
+        (prog1
+            (string-to-number (buffer-substring (point) (+ (point) 2)) 16)
+          (delete-region (1- (point)) (+ (point) 2)))))
+      ;; Encode using the charset, if any.
+      (when (and (< (length elems) 1)
+                (not (equal (intern (car elems)) 'us-ascii)))
+       (mm-decode-coding-region (point-min) (point-max)
+                                (intern (car elems))))
+      (buffer-string))))
+
+(provide 'rfc2231)
+
+;;; rfc2231.el ends here