1 ;;; mel-b-el.el --- Base64 encoder/decoder.
3 ;; Copyright (C) 1992,1995,1996,1997,1998,1999 Free Software Foundation, Inc.
5 ;; Author: ENAMI Tsugutomo <enami@sys.ptg.sony.co.jp>
6 ;; MORIOKA Tomohiko <tomo@m17n.org>
8 ;; Keywords: MIME, Base64
10 ;; This file is part of FLIM (Faithful Library about Internet Message).
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 this program; 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.
36 "Base64 encoder/decoder"
39 (defcustom base64-external-encoder '("mmencode")
40 "*list of base64 encoder program name and its arguments."
42 :type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
44 (defcustom base64-external-decoder '("mmencode" "-u")
45 "*list of base64 decoder program name and its arguments."
47 :type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
49 (defcustom base64-external-decoder-option-to-specify-file '("-o")
50 "*list of options of base64 decoder program to specify file."
52 :type '(repeat :tag "Arguments" string))
54 (defcustom base64-internal-encoding-limit 1000
55 "*limit size to use internal base64 encoder.
56 If size of input to encode is larger than this limit,
57 external encoder is called."
59 :type '(choice (const :tag "Always use internal encoder" nil)
60 (integer :tag "Size")))
62 (defcustom base64-internal-decoding-limit (if (and (featurep 'xemacs)
66 "*limit size to use internal base64 decoder.
67 If size of input to decode is larger than this limit,
68 external decoder is called."
70 :type '(choice (const :tag "Always use internal decoder" nil)
71 (integer :tag "Size")))
74 ;;; @ utility function
77 (defun pack-sequence (seq size)
78 "Split sequence SEQ into SIZE elements packs, and return list of packs.
79 \[mel-b-el; tl-seq function]"
80 (let ((len (length seq))
84 (setq unit (cons (elt seq p) unit))
86 (when (zerop (mod p size))
87 (setq dest (cons (nreverse unit) dest))
90 (nreverse (cons (nreverse unit) dest))
94 ;;; @ internal base64 encoder
95 ;;; based on base64 decoder by Enami Tsugutomo
98 (defconst base64-characters
99 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
102 (defmacro base64-num-to-char (n)
103 (` (aref base64-characters (, n))))
105 (defun base64-encode-1 (pack)
106 (let ((buf (make-string 4 ?=)))
107 (aset buf 0 (base64-num-to-char (ash (car pack) -2)))
110 (aset buf 1 (base64-num-to-char
111 (logior (ash (logand (car pack) 3) 4)
112 (ash (nth 1 pack) -4))))
115 (aset buf 2 (base64-num-to-char
116 (logior (ash (logand (nth 1 pack) 15) 2)
117 (ash (nth 2 pack) -6))))
118 (aset buf 3 (base64-num-to-char
119 (logand (nth 2 pack) 63))))
120 (aset buf 2 (base64-num-to-char
121 (ash (logand (nth 1 pack) 15) 2)))))
122 (aset buf 1 (base64-num-to-char
123 (ash (logand (car pack) 3) 4))))
126 (defun-maybe base64-encode-string (string)
127 "Encode STRING to base64, and return the result."
128 (let* ((len (length string))
135 (function base64-encode-1)
136 (pack-sequence (substring string b e) 3)
143 (function base64-encode-1)
144 (pack-sequence (substring string b) 3)
147 (defun base64-internal-encode-region (beg end)
150 (narrow-to-region beg end)
153 (base64-encode-string
154 (buffer-substring beg end))
155 (delete-region beg end)))
156 (or (bolp) (insert ?\n)))))
159 ;;; @ internal base64 decoder
162 (defconst base64-numbers
164 (let ((len (length base64-characters))
165 (vec (make-vector 123 nil))
168 (aset vec (aref base64-characters i) i)
172 (defmacro base64-char-to-num (c)
173 (` (aref base64-numbers (, c))))
175 (defsubst base64-internal-decode (string buffer)
176 (let* ((len (length string))
181 (when (prog1 (setq v1 (base64-char-to-num (aref string i)))
183 (setq v2 (base64-char-to-num (aref string i))
185 v3 (base64-char-to-num (aref string i))
187 (aset buffer j (logior (lsh v1 2)(lsh v2 -4)))
190 (let ((v4 (base64-char-to-num (aref string i))))
192 (aset buffer j (logior (lsh (logand v2 15) 4)(lsh v3 -2)))
195 (aset buffer (prog1 j (setq j (1+ j)))
196 (logior (lsh (logand v3 3) 6) v4))
199 (substring buffer 0 j)))
201 (defun base64-internal-decode-string (string)
202 (base64-internal-decode string (make-string (length string) 0)))
204 ;; (defsubst base64-decode-string! (string)
205 ;; (setq string (string-as-unibyte string))
206 ;; (base64-internal-decode string string))
208 (defun base64-internal-decode-region (beg end)
210 (let ((str (string-as-unibyte (buffer-substring beg end))))
213 (base64-internal-decode str str)
214 (delete-region beg end))))))
216 ;; (defun base64-internal-decode-region2 (beg end)
218 ;; (let ((str (buffer-substring beg end)))
219 ;; (delete-region beg end)
221 ;; (insert (base64-decode-string! str)))))
223 ;; (defun base64-internal-decode-region3 (beg end)
225 ;; (let ((str (buffer-substring beg end)))
226 ;; (delete-region beg end)
228 ;; (insert (base64-internal-decode-string str)))))
231 ;;; @ external encoder/decoder
234 (defun base64-external-encode-region (beg end)
237 (narrow-to-region beg end)
239 (apply (function call-process-region)
240 beg end (car base64-external-encoder)
242 (cdr base64-external-encoder)))
244 ;; regularize line break code
245 (goto-char (point-min))
246 (while (re-search-forward "\r$" nil t)
247 (replace-match "")))))
249 (defun base64-external-decode-region (beg end)
252 (apply (function call-process-region)
253 beg end (car base64-external-decoder)
255 (cdr base64-external-decoder)))))
257 (defun base64-external-decode-string (string)
261 (apply (function call-process-region)
262 (point-min)(point-max) (car base64-external-decoder)
264 (cdr base64-external-decoder)))
268 ;;; @ application interfaces
271 (defun-maybe base64-encode-region (start end)
272 "Encode current region by base64.
273 START and END are buffer positions.
274 This function calls internal base64 encoder if size of region is
275 smaller than `base64-internal-encoding-limit', otherwise it calls
276 external base64 encoder specified by `base64-external-encoder'. In
277 this case, you must install the program (maybe mmencode included in
278 metamail or XEmacs package)."
280 (if (and base64-internal-encoding-limit
281 (> (- end start) base64-internal-encoding-limit))
282 (base64-external-encode-region start end)
283 (base64-internal-encode-region start end)))
285 (defun-maybe base64-decode-region (start end)
286 "Decode current region by base64.
287 START and END are buffer positions.
288 This function calls internal base64 decoder if size of region is
289 smaller than `base64-internal-decoding-limit', otherwise it calls
290 external base64 decoder specified by `base64-external-decoder'. In
291 this case, you must install the program (maybe mmencode included in
292 metamail or XEmacs package)."
294 (if (and base64-internal-decoding-limit
295 (> (- end start) base64-internal-decoding-limit))
296 (base64-external-decode-region start end)
297 (base64-internal-decode-region start end)))
299 (defun-maybe base64-decode-string (string)
300 "Decode STRING which is encoded in base64, and return the result.
301 This function calls internal base64 decoder if size of STRING is
302 smaller than `base64-internal-decoding-limit', otherwise it calls
303 external base64 decoder specified by `base64-external-decoder'. In
304 this case, you must install the program (maybe mmencode included in
305 metamail or XEmacs package)."
306 (if (and base64-internal-decoding-limit
307 (> (length string) base64-internal-decoding-limit))
308 (base64-external-decode-string string)
309 (base64-internal-decode-string string)))
312 (mel-define-method-function (mime-encode-string string (nil "base64"))
313 'base64-encode-string)
314 (mel-define-method-function (mime-decode-string string (nil "base64"))
315 'base64-decode-string)
316 (mel-define-method-function (mime-encode-region start end (nil "base64"))
317 'base64-encode-region)
318 (mel-define-method-function (mime-decode-region start end (nil "base64"))
319 'base64-decode-region)
321 (mel-define-method-function (encoded-text-encode-string string (nil "B"))
322 'base64-encode-string)
324 (mel-define-method encoded-text-decode-string (string (nil "B"))
325 (if (string-match (eval-when-compile
326 (concat "\\`" B-encoded-text-regexp "\\'"))
328 (base64-decode-string string)
329 (error "Invalid encoded-text %s" string)))
331 (defun base64-insert-encoded-file (filename)
332 "Encode contents of file FILENAME to base64, and insert the result.
333 It calls external base64 encoder specified by
334 `base64-external-encoder'. So you must install the program (maybe
335 mmencode included in metamail or XEmacs package)."
336 (interactive "*fInsert encoded file: ")
337 (if (and base64-internal-encoding-limit
338 (> (nth 7 (file-attributes filename))
339 base64-internal-encoding-limit))
340 (apply (function call-process)
341 (car base64-external-encoder)
343 (cdr base64-external-encoder))
345 (base64-encode-string
347 (set-buffer-multibyte nil)
348 (insert-file-contents-as-binary filename)
350 (or (bolp) (insert ?\n))))
352 (mel-define-method-function (mime-insert-encoded-file filename (nil "base64"))
353 'base64-insert-encoded-file)
355 (defun base64-write-decoded-region (start end filename)
356 "Decode and write current region encoded by base64 into FILENAME.
357 START and END are buffer positions."
358 (interactive "*r\nFWrite decoded region to file: ")
359 (if (and base64-internal-decoding-limit
360 (> (- end start) base64-internal-decoding-limit))
362 (apply (function call-process-region)
363 start end (car base64-external-decoder)
365 (append (cdr base64-external-decoder)
366 base64-external-decoder-option-to-specify-file
368 (let ((str (buffer-substring start end)))
370 (insert (base64-internal-decode-string str))
371 (write-region-as-binary (point-min) (point-max) filename)))))
373 (mel-define-method-function
374 (mime-write-decoded-region start end filename (nil "base64"))
375 'base64-write-decoded-region)
383 ;;; mel-b-el.el ends here.