1 ;;; mel-b-el.el --- Base64 encoder/decoder.
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 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))
89 (setq dest (cons (nreverse unit) dest))
94 (cons (nreverse unit) dest)
98 ;;; @ internal base64 encoder
99 ;;; based on base64 decoder by Enami Tsugutomo
102 (defconst base64-characters
103 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
106 (defmacro base64-num-to-char (n)
107 `(aref base64-characters ,n))
109 (defun base64-encode-1 (pack)
114 (char-to-string (base64-num-to-char (ash a -2)))
118 (base64-num-to-char (logior (ash (logand a 3) 4) (ash b -4))))
122 (base64-num-to-char (logior (ash (logand b 15) 2) (ash c -6))))
123 (char-to-string (base64-num-to-char (logand c 63))))
124 (concat (char-to-string
125 (base64-num-to-char (ash (logand b 15) 2))) "=")))
126 (concat (char-to-string
127 (base64-num-to-char (ash (logand a 3) 4))) "==")))))
129 (defun-maybe base64-encode-string (string)
130 "Encode STRING to base64, and return the result."
131 (let* ((len (length string))
139 (function base64-encode-1)
140 (pack-sequence (substring string b e) 3)
147 (function base64-encode-1)
148 (pack-sequence (substring string b) 3)
153 (defun base64-internal-encode-region (beg end)
156 (narrow-to-region beg end)
159 (base64-encode-string
160 (buffer-substring beg end))
161 (delete-region beg end)))
162 (or (bolp) (insert ?\n)))))
165 ;;; @ internal base64 decoder
168 (defconst base64-numbers
170 (let ((len (length base64-characters))
171 (vec (make-vector 123 nil))
174 (aset vec (aref base64-characters i) i)
178 (defmacro base64-char-to-num (c)
179 `(aref base64-numbers ,c))
181 (defsubst base64-internal-decode (string buffer)
182 (let* ((len (length string))
187 (when (prog1 (setq v1 (base64-char-to-num (aref string i)))
189 (setq v2 (base64-char-to-num (aref string i))
191 v3 (base64-char-to-num (aref string i))
193 (aset buffer j (logior (lsh v1 2)(lsh v2 -4)))
196 (let ((v4 (base64-char-to-num (aref string i))))
198 (aset buffer j (logior (lsh (logand v2 15) 4)(lsh v3 -2)))
201 (aset buffer (prog1 j (setq j (1+ j)))
202 (logior (lsh (logand v3 3) 6) v4))
205 (substring buffer 0 j)))
207 (defun base64-internal-decode-string (string)
208 (base64-internal-decode string (make-string (length string) 0)))
210 ;; (defsubst base64-decode-string! (string)
211 ;; (setq string (string-as-unibyte string))
212 ;; (base64-internal-decode string string))
214 (defun base64-internal-decode-region (beg end)
216 (let ((str (string-as-unibyte (buffer-substring beg end))))
219 (base64-internal-decode str str)
220 (delete-region beg end))))))
222 ;; (defun base64-internal-decode-region2 (beg end)
224 ;; (let ((str (buffer-substring beg end)))
225 ;; (delete-region beg end)
227 ;; (insert (base64-decode-string! str)))))
229 ;; (defun base64-internal-decode-region3 (beg end)
231 ;; (let ((str (buffer-substring beg end)))
232 ;; (delete-region beg end)
234 ;; (insert (base64-internal-decode-string str)))))
237 ;;; @ external encoder/decoder
240 (defun base64-external-encode-region (beg end)
243 (narrow-to-region beg end)
245 (apply (function call-process-region)
246 beg end (car base64-external-encoder)
248 (cdr base64-external-encoder)))
250 ;; regularize line break code
251 (goto-char (point-min))
252 (while (re-search-forward "\r$" nil t)
253 (replace-match "")))))
255 (defun base64-external-decode-region (beg end)
258 (apply (function call-process-region)
259 beg end (car base64-external-decoder)
261 (cdr base64-external-decoder)))))
263 (defun base64-external-decode-string (string)
267 (apply (function call-process-region)
268 (point-min)(point-max) (car base64-external-decoder)
270 (cdr base64-external-decoder)))
274 ;;; @ application interfaces
277 (defun-maybe base64-encode-region (start end)
278 "Encode current region by base64.
279 START and END are buffer positions.
280 This function calls internal base64 encoder if size of region is
281 smaller than `base64-internal-encoding-limit', otherwise it calls
282 external base64 encoder specified by `base64-external-encoder'. In
283 this case, you must install the program (maybe mmencode included in
284 metamail or XEmacs package)."
286 (if (and base64-internal-encoding-limit
287 (> (- end start) base64-internal-encoding-limit))
288 (base64-external-encode-region start end)
289 (base64-internal-encode-region start end)))
291 (defun-maybe base64-decode-region (start end)
292 "Decode current region by base64.
293 START and END are buffer positions.
294 This function calls internal base64 decoder if size of region is
295 smaller than `base64-internal-decoding-limit', otherwise it calls
296 external base64 decoder specified by `base64-external-decoder'. In
297 this case, you must install the program (maybe mmencode included in
298 metamail or XEmacs package)."
300 (if (and base64-internal-decoding-limit
301 (> (- end start) base64-internal-decoding-limit))
302 (base64-external-decode-region start end)
303 (base64-internal-decode-region start end)))
305 (defun-maybe base64-decode-string (string)
306 "Decode STRING which is encoded in base64, and return the result.
307 This function calls internal base64 decoder if size of STRING is
308 smaller than `base64-internal-decoding-limit', otherwise it calls
309 external base64 decoder specified by `base64-external-decoder'. In
310 this case, you must install the program (maybe mmencode included in
311 metamail or XEmacs package)."
312 (if (and base64-internal-decoding-limit
313 (> (length string) base64-internal-decoding-limit))
314 (base64-external-decode-string string)
315 (base64-internal-decode-string string)))
318 (mel-define-method-function (mime-encode-string string (nil "base64"))
319 'base64-encode-string)
320 (mel-define-method-function (mime-decode-string string (nil "base64"))
321 'base64-decode-string)
322 (mel-define-method-function (mime-encode-region start end (nil "base64"))
323 'base64-encode-region)
324 (mel-define-method-function (mime-decode-region start end (nil "base64"))
325 'base64-decode-region)
327 (mel-define-method-function (encoded-text-encode-string string (nil "B"))
328 'base64-encode-string)
330 (mel-define-method encoded-text-decode-string (string (nil "B"))
331 (if (string-match (eval-when-compile
332 (concat "\\`" B-encoded-text-regexp "\\'"))
334 (base64-decode-string string)
335 (error "Invalid encoded-text %s" string)))
337 (defun base64-insert-encoded-file (filename)
338 "Encode contents of file FILENAME to base64, and insert the result.
339 It calls external base64 encoder specified by
340 `base64-external-encoder'. So you must install the program (maybe
341 mmencode included in metamail or XEmacs package)."
342 (interactive "*fInsert encoded file: ")
343 (if (and base64-internal-encoding-limit
344 (> (nth 7 (file-attributes filename))
345 base64-internal-encoding-limit))
346 (apply (function call-process)
347 (car base64-external-encoder)
349 (cdr base64-external-encoder))
351 (base64-encode-string
353 (set-buffer-multibyte nil)
354 (insert-file-contents-as-binary filename)
356 (or (bolp) (insert ?\n))))
358 (mel-define-method-function (mime-insert-encoded-file filename (nil "base64"))
359 'base64-insert-encoded-file)
361 (defun base64-write-decoded-region (start end filename)
362 "Decode and write current region encoded by base64 into FILENAME.
363 START and END are buffer positions."
364 (interactive "*r\nFWrite decoded region to file: ")
365 (if (and base64-internal-decoding-limit
366 (> (- end start) base64-internal-decoding-limit))
368 (apply (function call-process-region)
369 start end (car base64-external-decoder)
371 (append (cdr base64-external-decoder)
372 base64-external-decoder-option-to-specify-file
374 (let ((str (buffer-substring start end)))
376 (insert (base64-internal-decode-string str))
377 (write-region-as-binary (point-min) (point-max) filename)))))
379 (mel-define-method-function
380 (mime-write-decoded-region start end filename (nil "base64"))
381 'base64-write-decoded-region)
389 ;;; mel-b-el.el ends here.