--- /dev/null
+;;; mel-b-el.el: Base64 encoder/decoder for GNU Emacs
+
+;; Copyright (C) 1992,1995,1996,1997,1998 Free Software Foundation, Inc.
+
+;; Author: ENAMI Tsugutomo <enami@sys.ptg.sony.co.jp>
+;; MORIOKA Tomohiko <morioka@jaist.ac.jp>
+;; Created: 1995/6/24
+;; Keywords: MIME, Base64
+
+;; This file is part of MEL (MIME Encoding Library).
+
+;; This program is free software; you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation; either version 2, or (at
+;; your option) any later version.
+
+;; This program is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;; General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Code:
+
+(require 'emu)
+(require 'mime-def)
+
+
+;;; @ variables
+;;;
+
+(defgroup base64 nil
+ "Base64 encoder/decoder"
+ :group 'mime)
+
+(defcustom base64-external-encoder '("mmencode")
+ "*list of base64 encoder program name and its arguments."
+ :group 'base64
+ :type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
+
+(defcustom base64-external-decoder '("mmencode" "-u")
+ "*list of base64 decoder program name and its arguments."
+ :group 'base64
+ :type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
+
+(defcustom base64-external-decoder-option-to-specify-file '("-o")
+ "*list of options of base64 decoder program to specify file."
+ :group 'base64
+ :type '(repeat :tag "Arguments" string))
+
+(defcustom base64-internal-encoding-limit 1000
+ "*limit size to use internal base64 encoder.
+If size of input to encode is larger than this limit,
+external encoder is called."
+ :group 'base64
+ :type '(choice (const :tag "Always use internal encoder" nil)
+ (integer :tag "Size")))
+
+(defcustom base64-internal-decoding-limit 70000
+ "*limit size to use internal base64 decoder.
+If size of input to decode is larger than this limit,
+external decoder is called."
+ :group 'base64
+ :type '(choice (const :tag "Always use internal decoder" nil)
+ (integer :tag "Size")))
+
+
+;;; @ internal base64 encoder
+;;; based on base64 decoder by Enami Tsugutomo
+
+(defconst base64-characters
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+
+(defmacro base64-num-to-char (n)
+ `(aref base64-characters ,n))
+
+(defun base64-encode-1 (pack)
+ (let ((a (car pack))
+ (b (nth 1 pack))
+ (c (nth 2 pack)))
+ (concat
+ (char-to-string (base64-num-to-char (ash a -2)))
+ (if b
+ (concat
+ (char-to-string
+ (base64-num-to-char (logior (ash (logand a 3) 4) (ash b -4))))
+ (if c
+ (concat
+ (char-to-string
+ (base64-num-to-char (logior (ash (logand b 15) 2) (ash c -6))))
+ (char-to-string (base64-num-to-char (logand c 63)))
+ )
+ (concat (char-to-string
+ (base64-num-to-char (ash (logand b 15) 2))) "=")
+ ))
+ (concat (char-to-string
+ (base64-num-to-char (ash (logand a 3) 4))) "==")
+ ))))
+
+(defun base64-encode-string (string)
+ "Encode STRING to base64, and return the result."
+ (let ((len (length string))
+ (b 0)(e 57)
+ dest)
+ (while (< e len)
+ (setq dest
+ (concat dest
+ (mapconcat
+ (function base64-encode-1)
+ (pack-sequence (substring string b e) 3)
+ "")
+ "\n"))
+ (setq b e
+ e (+ e 57)
+ )
+ )
+ (let* ((es (mapconcat
+ (function base64-encode-1)
+ (pack-sequence (substring string b) 3)
+ ""))
+ (m (mod (length es) 4))
+ )
+ (concat dest es (cond ((= m 3) "=")
+ ((= m 2) "==")
+ ))
+ )))
+
+(defun base64-internal-encode-region (beg end)
+ (save-excursion
+ (save-restriction
+ (narrow-to-region beg end)
+ (let ((str (buffer-substring beg end)))
+ (delete-region beg end)
+ (insert (base64-encode-string str))
+ )
+ (or (bolp)
+ (insert "\n")
+ )
+ )))
+
+
+;;; @ internal base64 decoder
+;;;
+
+(defconst base64-numbers
+ `,(let ((len (length base64-characters))
+ (vec (make-vector 123 nil))
+ (i 0))
+ (while (< i len)
+ (aset vec (aref base64-characters i) i)
+ (setq i (1+ i)))
+ vec))
+
+(defmacro base64-char-to-num (c)
+ `(aref base64-numbers ,c))
+
+(defsubst base64-internal-decode (string buffer)
+ (let* ((len (length string))
+ (i 0)
+ (j 0)
+ v1 v2 v3)
+ (catch 'tag
+ (while (< i len)
+ (when (prog1 (setq v1 (base64-char-to-num (aref string i)))
+ (setq i (1+ i)))
+ (setq v2 (base64-char-to-num (aref string i))
+ i (1+ i)
+ v3 (base64-char-to-num (aref string i))
+ i (1+ i))
+ (aset buffer j (logior (lsh v1 2)(lsh v2 -4)))
+ (setq j (1+ j))
+ (if v3
+ (let ((v4 (base64-char-to-num (aref string i))))
+ (setq i (1+ i))
+ (aset buffer j (logior (lsh (logand v2 15) 4)(lsh v3 -2)))
+ (setq j (1+ j))
+ (if v4
+ (aset buffer (prog1 j (setq j (1+ j)))
+ (logior (lsh (logand v3 3) 6) v4))
+ (throw 'tag nil)
+ ))
+ (throw 'tag nil)
+ ))))
+ (substring buffer 0 j)
+ ))
+
+(defun base64-internal-decode-string (string)
+ (base64-internal-decode string (make-string (length string) 0)))
+
+(defsubst base64-decode-string! (string)
+ (base64-internal-decode string string))
+
+(defun base64-internal-decode-region (beg end)
+ (save-excursion
+ (let ((str (buffer-substring beg end)))
+ (delete-region beg end)
+ (goto-char beg)
+ (insert (base64-decode-string! str)))))
+
+
+;;; @ external encoder/decoder
+;;;
+
+(defun base64-external-encode-region (beg end)
+ (save-excursion
+ (save-restriction
+ (narrow-to-region beg end)
+ (as-binary-process
+ (apply (function call-process-region)
+ beg end (car base64-external-encoder)
+ t t nil (cdr base64-external-encoder)))
+ ;; for OS/2
+ ;; regularize line break code
+ (goto-char (point-min))
+ (while (re-search-forward "\r$" nil t)
+ (replace-match ""))
+ )))
+
+(defun base64-external-decode-region (beg end)
+ (save-excursion
+ (as-binary-process
+ (apply (function call-process-region)
+ beg end (car base64-external-decoder)
+ t t nil (cdr base64-external-decoder)))
+ ))
+
+(defun base64-external-decode-string (string)
+ (with-temp-buffer
+ (insert string)
+ (as-binary-process
+ (apply (function call-process-region)
+ (point-min) (point-max)
+ (car base64-external-decoder)
+ t t nil (cdr base64-external-decoder)))
+ (buffer-string)))
+
+
+;;; @ application interfaces
+;;;
+
+(defun base64-encode-region (start end)
+ "Encode current region by base64.
+START and END are buffer positions.
+This function calls internal base64 encoder if size of region is
+smaller than `base64-internal-encoding-limit', otherwise it calls
+external base64 encoder specified by `base64-external-encoder'. In
+this case, you must install the program (maybe mmencode included in
+metamail or XEmacs package)."
+ (interactive "r")
+ (if (and base64-internal-encoding-limit
+ (> (- end start) base64-internal-encoding-limit))
+ (base64-external-encode-region start end)
+ (base64-internal-encode-region start end)))
+
+(defun base64-decode-region (start end)
+ "Decode current region by base64.
+START and END are buffer positions.
+This function calls internal base64 decoder if size of region is
+smaller than `base64-internal-decoding-limit', otherwise it calls
+external base64 decoder specified by `base64-external-decoder'. In
+this case, you must install the program (maybe mmencode included in
+metamail or XEmacs package)."
+ (interactive "r")
+ (if (and base64-internal-decoding-limit
+ (> (- end start) base64-internal-decoding-limit))
+ (base64-external-decode-region start end)
+ (base64-internal-decode-region start end)))
+
+(defun base64-decode-string (string)
+ "Decode STRING which is encoded in base64, and return the result.
+This function calls internal base64 decoder if size of STRING is
+smaller than `base64-internal-decoding-limit', otherwise it calls
+external base64 decoder specified by `base64-external-decoder'. In
+this case, you must install the program (maybe mmencode included in
+metamail or XEmacs package)."
+ (interactive "r")
+ (if (and base64-internal-decoding-limit
+ (> (length string) base64-internal-decoding-limit))
+ (base64-external-decode-string string)
+ (base64-internal-decode-string string)))
+
+
+(defun base64-insert-encoded-file (filename)
+ "Encode contents of file FILENAME to base64, and insert the result.
+It calls external base64 encoder specified by
+`base64-external-encoder'. So you must install the program (maybe
+mmencode included in metamail or XEmacs package)."
+ (interactive (list (read-file-name "Insert encoded file: ")))
+ (if (and base64-internal-encoding-limit
+ (> (nth 7 (file-attributes filename))
+ base64-internal-encoding-limit))
+ (apply (function call-process) (car base64-external-encoder)
+ filename t nil (cdr base64-external-encoder))
+ (insert
+ (base64-encode-string
+ (with-temp-buffer
+ (insert-file-contents-as-binary filename)
+ (buffer-string))))
+ (or (bolp)
+ (insert "\n"))
+ ))
+
+(defun base64-write-decoded-region (start end filename)
+ "Decode and write current region encoded by base64 into FILENAME.
+START and END are buffer positions."
+ (interactive
+ (list (region-beginning) (region-end)
+ (read-file-name "Write decoded region to file: ")))
+ (if (and base64-internal-decoding-limit
+ (> (- end start) base64-internal-decoding-limit))
+ (as-binary-process
+ (apply (function call-process-region)
+ start end (car base64-external-decoder)
+ nil nil nil
+ (append (cdr base64-external-decoder)
+ base64-external-decoder-option-to-specify-file
+ (list filename))))
+ (let ((str (buffer-substring start end)))
+ (with-temp-buffer
+ (insert (base64-internal-decode-string str))
+ (write-region-as-binary (point-min) (point-max) filename)))))
+
+
+;;; @ etc
+;;;
+
+(defun pack-sequence (seq size)
+ "Split sequence SEQ into SIZE elements packs,
+and return list of packs. [mel-b-el; tl-seq function]"
+ (let ((len (length seq)) (p 0) obj
+ unit (i 0)
+ dest)
+ (while (< p len)
+ (setq obj (elt seq p))
+ (setq unit (cons obj unit))
+ (setq i (1+ i))
+ (if (= i size)
+ (progn
+ (setq dest (cons (reverse unit) dest))
+ (setq unit nil)
+ (setq i 0)
+ ))
+ (setq p (1+ p))
+ )
+ (if unit
+ (setq dest (cons (reverse unit) dest))
+ )
+ (reverse dest)
+ ))
+
+
+;;; @ end
+;;;
+
+(provide 'mel-b-el)
+
+;;; mel-b-el.el ends here.
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