mel-q.el

   1 ;;; mel-q.el: Quoted-Printable and Q-encoding encoder/decoder for GNU Emacs
   2
   3 ;; Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
   4
   5 ;; Author: MORIOKA Tomohiko <morioka@jaist.ac.jp>
   6 ;; Created: 1995/6/25
   7 ;; Keywords: MIME, Quoted-Printable, Q-encoding
   8
   9 ;; This file is part of MEL (MIME Encoding Library).
  10
  11 ;; This program is free software; you can redistribute it and/or
  12 ;; modify it under the terms of the GNU General Public License as
  13 ;; published by the Free Software Foundation; either version 2, or (at
  14 ;; your option) any later version.
  15
  16 ;; This program is distributed in the hope that it will be useful, but
  17 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19 ;; 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; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Code:
  27
  28 (require 'emu)
  29 (require 'mime-def)
  30
  31
  32 ;;; @ Quoted-Printable encoder
  33 ;;;
  34
  35 (defsubst quoted-printable-quote-char (character)
  36   (concat
  37    "="
  38    (char-to-string (aref quoted-printable-hex-chars (ash character -4)))
  39    (char-to-string (aref quoted-printable-hex-chars (logand character 15)))
  40    ))
  41
  42 (defun quoted-printable-internal-encode-region (start end)
  43   (save-excursion
  44     (save-restriction
  45       (narrow-to-region start end)
  46       (goto-char start)
  47       (let ((col 0))
  48         (while (< (point)(point-max))
  49           (cond ((>= col 75)
  50                  (insert "=\n")
  51                  (setq col 0)
  52                  )
  53                 ((looking-at-as-unibyte "^From ")
  54                  (replace-match "=46rom ")
  55                  (backward-char 1)
  56                  (setq col (+ col 6))
  57                  )
  58                 ((looking-at-as-unibyte "[ \t]\n")
  59                  (forward-char 1)
  60                  (insert "=\n")
  61                  (forward-char 1)
  62                  (setq col 0)
  63                  )
  64                 (t
  65                  (let ((chr (char-after (point))))
  66                    (cond ((= chr ?\n)
  67                           (forward-char 1)
  68                           (setq col 0)
  69                           )
  70                          ((or (= chr ?\t)
  71                               (and (<= 32 chr)(/= chr ?=)(< chr 127))
  72                               )
  73                           (forward-char 1)
  74                           (setq col (1+ col))
  75                           )
  76                          ((>= col 73)
  77                           (insert "=\n")
  78                           (setq col 0)
  79                           )
  80                          (t
  81                           (delete-char 1)
  82                           (insert (quoted-printable-quote-char chr))
  83                           (setq col (+ col 3))
  84                           ))
  85                    )))
  86           )))))
  87
  88
  89 (defvar quoted-printable-external-encoder '("mmencode" "-q")
  90   "*list of quoted-printable encoder program name and its arguments.")
  91
  92 (defun quoted-printable-external-encode-region (start end)
  93   (save-excursion
  94     (save-restriction
  95       (narrow-to-region start end)
  96       (as-binary-process
  97        (apply (function call-process-region)
  98               start end (car quoted-printable-external-encoder)
  99               t t nil (cdr quoted-printable-external-encoder))
 100        )
 101       ;; for OS/2
 102       ;;   regularize line break code
 103       (goto-char (point-min))
 104       (while (re-search-forward "\r$" nil t)
 105         (replace-match "")
 106         )
 107       )))
 108
 109 (defun quoted-printable-internal-encode-string (string)
 110   "Encode STRING to quoted-printable, and return the result."
 111   (with-temp-buffer
 112     (insert string)
 113     (quoted-printable-internal-encode-region (point-min)(point-max))
 114     (buffer-string)
 115     ))
 116
 117 (defun quoted-printable-external-encode-string (string)
 118   "Encode STRING to quoted-printable, and return the result."
 119   (with-temp-buffer
 120     (insert string)
 121     (quoted-printable-external-encode-region (point-min)(point-max))
 122     (buffer-string)
 123     ))
 124
 125 (defun quoted-printable-external-insert-encoded-file (filename)
 126   "Encode contents of file FILENAME to quoted-printable, and insert the result.
 127 It calls external quoted-printable encoder specified by
 128 `quoted-printable-external-encoder'.  So you must install the program
 129 \(maybe mmencode included in metamail or XEmacs package)."
 130   (interactive (list (read-file-name "Insert encoded file: ")))
 131   (apply (function call-process) (car quoted-printable-external-encoder)
 132          filename t nil (cdr quoted-printable-external-encoder))
 133   )
 134
 135
 136 ;;; @ Quoted-Printable decoder
 137 ;;;
 138
 139 (defsubst quoted-printable-hex-char-to-num (chr)
 140   (cond ((<= ?a chr) (+ (- chr ?a) 10))
 141         ((<= ?A chr) (+ (- chr ?A) 10))
 142         ((<= ?0 chr) (- chr ?0))
 143         ))
 144
 145 (defun quoted-printable-internal-decode-region (start end)
 146   (save-excursion
 147     (save-restriction
 148       (narrow-to-region start end)
 149       (goto-char (point-min))
 150       (while (search-forward "=" nil t)
 151         (let ((beg (match-beginning 0)))
 152           (cond ((looking-at "\n")
 153                  (delete-region beg (match-end 0))
 154                  )
 155                 ((looking-at
 156                   `,(concat "[" quoted-printable-hex-chars
 157                             "][" quoted-printable-hex-chars "]"))
 158                  (let* ((end (match-end 0))
 159                         (hex (buffer-substring (match-beginning 0) end)))
 160                    (delete-region beg end)
 161                    (insert
 162                     (logior
 163                      (ash (quoted-printable-hex-char-to-num (aref hex 0)) 4)
 164                      (quoted-printable-hex-char-to-num (aref hex 1))))
 165                    ))
 166                 (t
 167                  ;; invalid
 168                  ))
 169           )))))
 170
 171 (defvar quoted-printable-external-decoder '("mmencode" "-q" "-u")
 172   "*list of quoted-printable decoder program name and its arguments.")
 173
 174 (defun quoted-printable-external-decode-region (start end)
 175   (save-excursion
 176     (as-binary-process
 177      (apply (function call-process-region)
 178             start end (car quoted-printable-external-decoder)
 179             t t nil (cdr quoted-printable-external-decoder))
 180      )))
 181
 182 (defun quoted-printable-internal-decode-string (string)
 183   "Decode STRING which is encoded in quoted-printable, and return the result."
 184   (with-temp-buffer
 185     (insert string)
 186     (quoted-printable-internal-decode-region (point-min)(point-max))
 187     (buffer-string)))
 188
 189 (defun quoted-printable-external-decode-string (string)
 190   "Decode STRING which is encoded in quoted-printable, and return the result."
 191   (with-temp-buffer
 192     (insert string)
 193     (quoted-printable-external-decode-region (point-min)(point-max))
 194     (buffer-string)))
 195
 196 (defvar quoted-printable-external-decoder-option-to-specify-file '("-o")
 197   "*list of options of quoted-printable decoder program to specify file.")
 198
 199 (defun quoted-printable-external-write-decoded-region (start end filename)
 200   "Decode and write current region encoded by quoted-printable into FILENAME.
 201 START and END are buffer positions."
 202   (interactive
 203    (list (region-beginning) (region-end)
 204          (read-file-name "Write decoded region to file: ")))
 205   (as-binary-process
 206    (apply (function call-process-region)
 207           start end (car quoted-printable-external-decoder)
 208           nil nil nil
 209           (append (cdr quoted-printable-external-decoder)
 210                   quoted-printable-external-decoder-option-to-specify-file
 211                   (list filename))
 212           )))
 213
 214 \f
 215 ;;; @ Q-encoding encode/decode string
 216 ;;;
 217
 218 (defconst q-encoding-special-chars-alist
 219   '((text       ?= ?? ?_)
 220     (comment    ?= ?? ?_ ?\( ?\) ?\\)
 221     (phrase     ?= ?? ?_ ?\( ?\) ?\\ ?\" ?# ?$ ?% ?& ?' ?, ?. ?/
 222                 ?: ?\; ?< ?> ?@ ?\[ ?\] ?^ ?` ?{ ?| ?} ?~)
 223     ))
 224
 225 (defun q-encoding-internal-encode-string (string &optional mode)
 226   "Encode STRING to Q-encoding of encoded-word, and return the result.
 227 MODE allows `text', `comment', `phrase' or nil.  Default value is
 228 `phrase'."
 229   (let ((specials (cdr (or (assq mode q-encoding-special-chars-alist)
 230                            (assq 'phrase q-encoding-special-chars-alist)
 231                            ))))
 232     (mapconcat (function
 233                 (lambda (chr)
 234                   (cond ((eq chr ? ) "_")
 235                         ((or (< chr 32) (< 126 chr)
 236                              (memq chr specials)
 237                              )
 238                          (quoted-printable-quote-char chr)
 239                          )
 240                         (t
 241                          (char-to-string chr)
 242                          ))
 243                   ))
 244                string "")
 245     ))
 246
 247 (defun q-encoding-internal-decode-string (string)
 248   "Decode STRING which is encoded in Q-encoding and return the result."
 249   (let (q h l)
 250     (mapconcat (function
 251                 (lambda (chr)
 252                   (cond ((eq chr ?_) " ")
 253                         ((eq chr ?=)
 254                          (setq q t)
 255                          "")
 256                         (q (setq h (quoted-printable-hex-char-to-num chr))
 257                            (setq q nil)
 258                            "")
 259                         (h (setq l (quoted-printable-hex-char-to-num chr))
 260                            (prog1
 261                                (char-to-string (logior (ash h 4) l))
 262                              (setq h nil)
 263                              )
 264                            )
 265                         (t (char-to-string chr))
 266                         )))
 267                string "")))
 268
 269
 270 ;;; @@ etc
 271 ;;;
 272
 273 (defun q-encoding-printable-char-p (chr mode)
 274   (and (not (memq chr '(?= ?? ?_)))
 275        (<= ?\   chr)(<= chr ?~)
 276        (cond ((eq mode 'text) t)
 277              ((eq mode 'comment)
 278               (not (memq chr '(?\( ?\) ?\\)))
 279               )
 280              (t
 281               (string-match "[A-Za-z0-9!*+/=_---]" (char-to-string chr))
 282               ))))
 283
 284 (defun q-encoding-internal-encoded-length (string &optional mode)
 285   (let ((l 0)(i 0)(len (length string)) chr)
 286     (while (< i len)
 287       (setq chr (elt string i))
 288       (if (q-encoding-printable-char-p chr mode)
 289           (setq l (+ l 1))
 290         (setq l (+ l 3))
 291         )
 292       (setq i (+ i 1)) )
 293     l))
 294
 295
 296 ;;; @ end
 297 ;;;
 298
 299 (provide 'mel-q)
 300
 301 ;;; mel-q.el ends here