lisp/gnus/qp.el

   1 ;;; qp.el --- Quoted-Printable functions
   2
   3 ;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
   4 ;;   2007, 2008, 2009, 2010  Free Software Foundation, Inc.
   5
   6 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   7 ;; Keywords: mail, extensions
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Functions for encoding and decoding quoted-printable text as
  27 ;; defined in RFC 2045.
  28
  29 ;;; Code:
  30
  31 (require 'mm-util)
  32 (defvar mm-use-ultra-safe-encoding)
  33
  34 ;;;###autoload
  35 (defun quoted-printable-decode-region (from to &optional coding-system)
  36   "Decode quoted-printable in the region between FROM and TO, per RFC 2045.
  37 If CODING-SYSTEM is non-nil, decode bytes into characters with that
  38 coding-system.
  39
  40 Interactively, you can supply the CODING-SYSTEM argument
  41 with \\[universal-coding-system-argument].
  42
  43 The CODING-SYSTEM argument is a historical hangover and is deprecated.
  44 QP encodes raw bytes and should be decoded into raw bytes.  Decoding
  45 them into characters should be done separately."
  46   (interactive
  47    ;; Let the user determine the coding system with "C-x RET c".
  48    (list (region-beginning) (region-end) coding-system-for-read))
  49   (unless (mm-coding-system-p coding-system) ; e.g. `ascii' from Gnus
  50     (setq coding-system nil))
  51   (save-excursion
  52     (save-restriction
  53       ;; RFC 2045:  ``An "=" followed by two hexadecimal digits, one
  54       ;; or both of which are lowercase letters in "abcdef", is
  55       ;; formally illegal. A robust implementation might choose to
  56       ;; recognize them as the corresponding uppercase letters.''
  57       (let ((case-fold-search t))
  58         (narrow-to-region from to)
  59         ;; Do this in case we're called from Gnus, say, in a buffer
  60         ;; which already contains non-ASCII characters which would
  61         ;; then get doubly-decoded below.
  62         (if coding-system
  63             (mm-encode-coding-region (point-min) (point-max) coding-system))
  64         (goto-char (point-min))
  65         (while (and (skip-chars-forward "^=")
  66                     (not (eobp)))
  67           (cond ((eq (char-after (1+ (point))) ?\n)
  68                  (delete-char 2))
  69                 ((looking-at "=[0-9A-F][0-9A-F]")
  70                  (let ((byte (string-to-number (buffer-substring (1+ (point))
  71                                                               (+ 3 (point)))
  72                                             16)))
  73                    (mm-insert-byte byte 1)
  74                    (delete-char 3)))
  75                 (t
  76                  (message "Malformed quoted-printable text")
  77                  (forward-char)))))
  78       (if coding-system
  79           (mm-decode-coding-region (point-min) (point-max) coding-system)))))
  80
  81 (defun quoted-printable-decode-string (string &optional coding-system)
  82   "Decode the quoted-printable encoded STRING and return the result.
  83 If CODING-SYSTEM is non-nil, decode the string with coding-system.
  84 Use of CODING-SYSTEM is deprecated; this function should deal with
  85 raw bytes, and coding conversion should be done separately."
  86   (mm-with-unibyte-buffer
  87     (insert string)
  88     (quoted-printable-decode-region (point-min) (point-max) coding-system)
  89     (buffer-string)))
  90
  91 (defun quoted-printable-encode-region (from to &optional fold class)
  92   "Quoted-printable encode the region between FROM and TO per RFC 2045.
  93
  94 If FOLD, fold long lines at 76 characters (as required by the RFC).
  95 If CLASS is non-nil, translate the characters not matched by that
  96 regexp class, which is in the form expected by `skip-chars-forward'.
  97 You should probably avoid non-ASCII characters in this arg.
  98
  99 If `mm-use-ultra-safe-encoding' is set, fold lines unconditionally and
 100 encode lines starting with \"From\"."
 101   (interactive "r")
 102   (unless class
 103     ;; Avoid using 8bit characters. = is \075.
 104     ;; Equivalent to "^\000-\007\013\015-\037\200-\377="
 105     (setq class "\010-\012\014\040-\074\076-\177"))
 106   (save-excursion
 107     (goto-char from)
 108     (if (re-search-forward (mm-string-to-multibyte "[^\x0-\x7f\x80-\xff]")
 109                            to t)
 110         (error "Multibyte character in QP encoding region"))
 111     (save-restriction
 112       (narrow-to-region from to)
 113       ;; Encode all the non-ascii and control characters.
 114       (goto-char (point-min))
 115       (while (and (skip-chars-forward class)
 116                   (not (eobp)))
 117         (insert
 118          (prog1
 119              ;; To unibyte in case of Emacs 23 (unicode) eight-bit.
 120              (format "=%02X" (mm-multibyte-char-to-unibyte (char-after)))
 121            (delete-char 1))))
 122       ;; Encode white space at the end of lines.
 123       (goto-char (point-min))
 124       (while (re-search-forward "[ \t]+$" nil t)
 125         (goto-char (match-beginning 0))
 126         (while (not (eolp))
 127           (insert
 128            (prog1
 129                (format "=%02X" (char-after))
 130              (delete-char 1)))))
 131       (let ((mm-use-ultra-safe-encoding
 132              (and (boundp 'mm-use-ultra-safe-encoding)
 133                   mm-use-ultra-safe-encoding)))
 134         (when (or fold mm-use-ultra-safe-encoding)
 135           (let ((tab-width 1))          ; HTAB is one character.
 136             (goto-char (point-min))
 137             (while (not (eobp))
 138               ;; In ultra-safe mode, encode "From " at the beginning
 139               ;; of a line.
 140               (when mm-use-ultra-safe-encoding
 141                 (if (looking-at "From ")
 142                     (replace-match "From=20" nil t)
 143                   (if (looking-at "-")
 144                       (replace-match "=2D" nil t))))
 145               (end-of-line)
 146               ;; Fold long lines.
 147               (while (> (current-column) 76) ; tab-width must be 1.
 148                 (beginning-of-line)
 149                 (forward-char 75)       ; 75 chars plus an "="
 150                 (search-backward "=" (- (point) 2) t)
 151                 (insert "=\n")
 152                 (end-of-line))
 153               (forward-line))))))))
 154
 155 (defun quoted-printable-encode-string (string)
 156   "Encode the STRING as quoted-printable and return the result."
 157   (with-temp-buffer
 158     (if (mm-multibyte-string-p string)
 159         (mm-enable-multibyte)
 160       (mm-disable-multibyte))
 161     (insert string)
 162     (quoted-printable-encode-region (point-min) (point-max))
 163     (buffer-string)))
 164
 165 (provide 'qp)
 166
 167 ;;; qp.el ends here