1 ;;; mel-b-el.el: Base64 encoder/decoder for GNU Emacs
3 ;; Copyright (C) 1992,1995,1996,1997,1998 Free Software Foundation, Inc.
5 ;; Author: ENAMI Tsugutomo <enami@sys.ptg.sony.co.jp>
6 ;; MORIOKA Tomohiko <morioka@jaist.ac.jp>
8 ;; Keywords: MIME, Base64
10 ;; This file is part of MEL (MIME Encoding Library).
12 ;; This program is free software; you can redistribute it and/or
13 ;; modify it under the terms of the GNU General Public License as
14 ;; published by the Free Software Foundation; either version 2, or (at
15 ;; your option) any later version.
17 ;; This program is distributed in the hope that it will be useful, but
18 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 ;; General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs; see the file COPYING. If not, write to the
24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
25 ;; Boston, MA 02111-1307, USA.
37 "Base64 encoder/decoder"
40 (defcustom base64-external-encoder '("mmencode")
41 "*list of base64 encoder program name and its arguments."
43 :type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
45 (defcustom base64-external-decoder '("mmencode" "-u")
46 "*list of base64 decoder program name and its arguments."
48 :type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
50 (defcustom base64-external-decoder-option-to-specify-file '("-o")
51 "*list of options of base64 decoder program to specify file."
53 :type '(repeat :tag "Arguments" string))
55 (defcustom base64-internal-encoding-limit 1000
56 "*limit size to use internal base64 encoder.
57 If size of input to encode is larger than this limit,
58 external encoder is called."
60 :type '(choice (const :tag "Always use internal encoder" nil)
61 (integer :tag "Size")))
63 (defcustom base64-internal-decoding-limit (if (and (featurep 'xemacs)
67 "*limit size to use internal base64 decoder.
68 If size of input to decode is larger than this limit,
69 external decoder is called."
71 :type '(choice (const :tag "Always use internal decoder" nil)
72 (integer :tag "Size")))
75 ;;; @ internal base64 encoder
76 ;;; based on base64 decoder by Enami Tsugutomo
79 (defconst base64-characters
80 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
83 (defmacro base64-num-to-char (n)
84 `(aref base64-characters ,n))
86 (defun base64-encode-1 (pack)
91 (char-to-string (base64-num-to-char (ash a -2)))
95 (base64-num-to-char (logior (ash (logand a 3) 4) (ash b -4))))
99 (base64-num-to-char (logior (ash (logand b 15) 2) (ash c -6))))
100 (char-to-string (base64-num-to-char (logand c 63)))
102 (concat (char-to-string
103 (base64-num-to-char (ash (logand b 15) 2))) "=")
105 (concat (char-to-string
106 (base64-num-to-char (ash (logand a 3) 4))) "==")
109 (defun-maybe base64-encode-string (string)
110 "Encode STRING to base64, and return the result."
111 (let ((len (length string))
118 (function base64-encode-1)
119 (pack-sequence (substring string b e) 3)
126 (let* ((es (mapconcat
127 (function base64-encode-1)
128 (pack-sequence (substring string b) 3)
130 (m (mod (length es) 4))
132 (concat dest es (cond ((= m 3) "=")
137 (defun base64-internal-encode-region (beg end)
140 (narrow-to-region beg end)
141 (let ((str (buffer-substring beg end)))
142 (delete-region beg end)
143 (insert (base64-encode-string str))
151 ;;; @ internal base64 decoder
154 (defconst base64-numbers
156 (let ((len (length base64-characters))
157 (vec (make-vector 123 nil))
160 (aset vec (aref base64-characters i) i)
164 (defmacro base64-char-to-num (c)
165 `(aref base64-numbers ,c))
167 (defsubst base64-internal-decode (string buffer)
168 (let* ((len (length string))
174 (when (prog1 (setq v1 (base64-char-to-num (aref string i)))
176 (setq v2 (base64-char-to-num (aref string i))
178 v3 (base64-char-to-num (aref string i))
180 (aset buffer j (logior (lsh v1 2)(lsh v2 -4)))
183 (let ((v4 (base64-char-to-num (aref string i))))
185 (aset buffer j (logior (lsh (logand v2 15) 4)(lsh v3 -2)))
188 (aset buffer (prog1 j (setq j (1+ j)))
189 (logior (lsh (logand v3 3) 6) v4))
194 (substring buffer 0 j)
197 (defun base64-internal-decode-string (string)
198 (base64-internal-decode string (make-string (length string) 0)))
200 ;; (defsubst base64-decode-string! (string)
201 ;; (setq string (string-as-unibyte string))
202 ;; (base64-internal-decode string string))
204 (defun base64-internal-decode-region (beg end)
206 (let ((str (string-as-unibyte (buffer-substring beg end))))
207 (delete-region beg end)
209 (insert (base64-internal-decode str str)))))
211 ;; (defun base64-internal-decode-region2 (beg end)
213 ;; (let ((str (buffer-substring beg end)))
214 ;; (delete-region beg end)
216 ;; (insert (base64-decode-string! str)))))
218 ;; (defun base64-internal-decode-region3 (beg end)
220 ;; (let ((str (buffer-substring beg end)))
221 ;; (delete-region beg end)
223 ;; (insert (base64-internal-decode-string str)))))
226 ;;; @ external encoder/decoder
229 (defun base64-external-encode-region (beg end)
232 (narrow-to-region beg end)
234 (apply (function call-process-region)
235 beg end (car base64-external-encoder)
236 t t nil (cdr base64-external-encoder)))
238 ;; regularize line break code
239 (goto-char (point-min))
240 (while (re-search-forward "\r$" nil t)
244 (defun base64-external-decode-region (beg end)
247 (apply (function call-process-region)
248 beg end (car base64-external-decoder)
249 t t nil (cdr base64-external-decoder)))
252 (defun base64-external-decode-string (string)
256 (apply (function call-process-region)
257 (point-min) (point-max)
258 (car base64-external-decoder)
259 t t nil (cdr base64-external-decoder)))
263 ;;; @ application interfaces
266 (defun-maybe base64-encode-region (start end)
267 "Encode current region by base64.
268 START and END are buffer positions.
269 This function calls internal base64 encoder if size of region is
270 smaller than `base64-internal-encoding-limit', otherwise it calls
271 external base64 encoder specified by `base64-external-encoder'. In
272 this case, you must install the program (maybe mmencode included in
273 metamail or XEmacs package)."
275 (if (and base64-internal-encoding-limit
276 (> (- end start) base64-internal-encoding-limit))
277 (base64-external-encode-region start end)
278 (base64-internal-encode-region start end)))
280 (defun-maybe base64-decode-region (start end)
281 "Decode current region by base64.
282 START and END are buffer positions.
283 This function calls internal base64 decoder if size of region is
284 smaller than `base64-internal-decoding-limit', otherwise it calls
285 external base64 decoder specified by `base64-external-decoder'. In
286 this case, you must install the program (maybe mmencode included in
287 metamail or XEmacs package)."
289 (if (and base64-internal-decoding-limit
290 (> (- end start) base64-internal-decoding-limit))
291 (base64-external-decode-region start end)
292 (base64-internal-decode-region start end)))
294 (defun-maybe base64-decode-string (string)
295 "Decode STRING which is encoded in base64, and return the result.
296 This function calls internal base64 decoder if size of STRING is
297 smaller than `base64-internal-decoding-limit', otherwise it calls
298 external base64 decoder specified by `base64-external-decoder'. In
299 this case, you must install the program (maybe mmencode included in
300 metamail or XEmacs package)."
302 (if (and base64-internal-decoding-limit
303 (> (length string) base64-internal-decoding-limit))
304 (base64-external-decode-string string)
305 (base64-internal-decode-string string)))
308 (mel-define-method-function (mime-encode-string string (nil "base64"))
309 'base64-encode-string)
310 (mel-define-method-function (mime-decode-string string (nil "base64"))
311 'base64-decode-string)
312 (mel-define-method-function (mime-encode-region start end (nil "base64"))
313 'base64-encode-region)
314 (mel-define-method-function (mime-decode-region start end (nil "base64"))
315 'base64-decode-region)
317 (mel-define-method-function (encoded-text-encode-string string (nil "B"))
318 'base64-encode-string)
320 (mel-define-method encoded-text-decode-string (string (nil "B"))
321 (if (and (string-match B-encoded-text-regexp string)
322 (string= string (match-string 0 string)))
323 (base64-decode-string string)
324 (error "Invalid encoded-text %s" string)))
326 (defun base64-insert-encoded-file (filename)
327 "Encode contents of file FILENAME to base64, and insert the result.
328 It calls external base64 encoder specified by
329 `base64-external-encoder'. So you must install the program (maybe
330 mmencode included in metamail or XEmacs package)."
331 (interactive (list (read-file-name "Insert encoded file: ")))
332 (if (and base64-internal-encoding-limit
333 (> (nth 7 (file-attributes filename))
334 base64-internal-encoding-limit))
335 (apply (function call-process) (car base64-external-encoder)
336 filename t nil (cdr base64-external-encoder))
338 (base64-encode-string
340 (set-buffer-multibyte nil)
341 (insert-file-contents-as-binary filename)
347 (mel-define-method-function (mime-insert-encoded-file filename (nil "base64"))
348 'base64-insert-encoded-file)
350 (defun base64-write-decoded-region (start end filename)
351 "Decode and write current region encoded by base64 into FILENAME.
352 START and END are buffer positions."
354 (list (region-beginning) (region-end)
355 (read-file-name "Write decoded region to file: ")))
356 (if (and base64-internal-decoding-limit
357 (> (- end start) base64-internal-decoding-limit))
359 (apply (function call-process-region)
360 start end (car base64-external-decoder)
362 (append (cdr base64-external-decoder)
363 base64-external-decoder-option-to-specify-file
365 (let ((str (buffer-substring start end)))
367 (insert (base64-internal-decode-string str))
368 (write-region-as-binary (point-min) (point-max) filename)
371 (mel-define-method-function
372 (mime-write-decoded-region start end filename (nil "base64"))
373 'base64-write-decoded-region)
379 (defun pack-sequence (seq size)
380 "Split sequence SEQ into SIZE elements packs,
381 and return list of packs. [mel-b-el; tl-seq function]"
382 (let ((len (length seq)) (p 0) obj
386 (setq obj (elt seq p))
387 (setq unit (cons obj unit))
391 (setq dest (cons (reverse unit) dest))
398 (setq dest (cons (reverse unit) dest))
409 ;;; mel-b-el.el ends here.