404 lines
13 KiB
EmacsLisp
404 lines
13 KiB
EmacsLisp
;;; mel-b-el.el --- Base64 encoder/decoder.
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;; Copyright (C) 1992,95,96,97,98,99,2001 Free Software Foundation, Inc.
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;; Author: ENAMI Tsugutomo <enami@sys.ptg.sony.co.jp>
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;; MORIOKA Tomohiko <tomo@m17n.org>
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;; Created: 1995/6/24
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;; Keywords: MIME, Base64
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;; This file is part of FLIM (Faithful Library about Internet Message).
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;; This program is free software; you can redistribute it and/or
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;; modify it under the terms of the GNU General Public License as
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;; published by the Free Software Foundation; either version 2, or (at
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;; your option) any later version.
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;; This program is distributed in the hope that it will be useful, but
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;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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;; General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with this program; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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;; Boston, MA 02110-1301, USA.
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;;; Code:
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(require 'mime-def)
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(eval-when-compile
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;; XXX: the macro `as-binary-process' should be provided when compiling.
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(require 'pces))
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;;; @ variables
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;;;
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(defgroup base64 nil
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"Base64 encoder/decoder"
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:group 'mime)
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(defcustom base64-external-encoder '("mmencode")
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"*list of base64 encoder program name and its arguments."
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:group 'base64
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:type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
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(defcustom base64-external-decoder '("mmencode" "-u")
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"*list of base64 decoder program name and its arguments."
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:group 'base64
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:type '(cons (file :tag "Command")(repeat :tag "Arguments" string)))
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(defcustom base64-external-decoder-option-to-specify-file '("-o")
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"*list of options of base64 decoder program to specify file.
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If the base64 decoder program does not have such option, set this as nil."
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:group 'base64
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:type '(repeat :tag "Arguments" string))
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(defcustom base64-internal-encoding-limit 1000
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"*limit size to use internal base64 encoder.
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If size of input to encode is larger than this limit,
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external encoder is called."
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:group 'base64
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:type '(choice (const :tag "Always use internal encoder" nil)
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(integer :tag "Size")))
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(defcustom base64-internal-decoding-limit (if (and (featurep 'xemacs)
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(featurep 'mule))
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1000
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7600)
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"*limit size to use internal base64 decoder.
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If size of input to decode is larger than this limit,
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external decoder is called."
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:group 'base64
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:type '(choice (const :tag "Always use internal decoder" nil)
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(integer :tag "Size")))
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;;; @ utility function
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;;;
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(defun pack-sequence (seq size)
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"Split sequence SEQ into SIZE elements packs, and return list of packs.
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\[mel-b-el; tl-seq function]"
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(let ((len (length seq))
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(p 0)
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dest unit)
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(while (< p len)
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(setq unit (cons (elt seq p) unit))
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(setq p (1+ p))
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(when (zerop (mod p size))
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(setq dest (cons (nreverse unit) dest))
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(setq unit nil)))
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(if unit
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(nreverse (cons (nreverse unit) dest))
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(nreverse dest))))
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;;; @ internal base64 encoder
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;;; based on base64 decoder by Enami Tsugutomo
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(eval-and-compile
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(defconst base64-characters
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
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)
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(defmacro base64-num-to-char (n)
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`(aref base64-characters ,n))
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(defun base64-encode-1 (pack)
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(let ((buf (make-string 4 ?=)))
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(aset buf 0 (base64-num-to-char (ash (car pack) -2)))
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(if (nth 1 pack)
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(progn
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(aset buf 1 (base64-num-to-char
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(logior (ash (logand (car pack) 3) 4)
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(ash (nth 1 pack) -4))))
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(if (nth 2 pack)
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(progn
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(aset buf 2 (base64-num-to-char
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(logior (ash (logand (nth 1 pack) 15) 2)
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(ash (nth 2 pack) -6))))
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(aset buf 3 (base64-num-to-char
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(logand (nth 2 pack) 63))))
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(aset buf 2 (base64-num-to-char
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(ash (logand (nth 1 pack) 15) 2)))))
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(aset buf 1 (base64-num-to-char
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(ash (logand (car pack) 3) 4))))
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buf))
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(defun-maybe base64-encode-string (string &optional no-line-break)
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"Base64-encode STRING and return the result.
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Optional second argument NO-LINE-BREAK means do not break long lines
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into shorter lines."
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(let* ((len (length string))
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(b 0)(e 57)
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(dest ""))
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(while (< e len)
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(setq dest
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(concat dest
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(mapconcat
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(function base64-encode-1)
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(pack-sequence (substring string b e) 3)
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"")
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(if (not no-line-break) "\n")))
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(setq b e
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e (+ e 57)))
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(concat dest
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(mapconcat
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(function base64-encode-1)
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(pack-sequence (substring string b) 3)
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""))))
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(defun base64-internal-encode-region (beg end &optional no-line-break)
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(save-excursion
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(save-restriction
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(narrow-to-region beg end)
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(insert
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(prog1
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(base64-encode-string (buffer-substring beg end) no-line-break)
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(delete-region beg end))))))
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;;; @ internal base64 decoder
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;;;
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(defconst base64-numbers
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(eval-when-compile
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(let ((len (length base64-characters))
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(vec (make-vector 123 nil))
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(i 0))
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(while (< i len)
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(aset vec (aref base64-characters i) i)
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(setq i (1+ i)))
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vec)))
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(defmacro base64-char-to-num (c)
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`(aref base64-numbers ,c))
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(defsubst base64-internal-decode (string buffer)
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(let* ((len (length string))
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(i 0)(j 0)
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v1 v2 v3)
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(catch 'tag
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(while (< i len)
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(when (prog1 (setq v1 (base64-char-to-num (aref string i)))
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(setq i (1+ i)))
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(setq v2 (base64-char-to-num (aref string i))
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i (1+ i)
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v3 (base64-char-to-num (aref string i))
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i (1+ i))
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(aset buffer j (logior (lsh v1 2)(lsh v2 -4)))
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(setq j (1+ j))
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(if v3
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(let ((v4 (base64-char-to-num (aref string i))))
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(setq i (1+ i))
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(aset buffer j (logior (lsh (logand v2 15) 4)(lsh v3 -2)))
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(setq j (1+ j))
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(if v4
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(aset buffer (prog1 j (setq j (1+ j)))
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(logior (lsh (logand v3 3) 6) v4))
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(throw 'tag nil)))
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(throw 'tag nil)))))
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(substring buffer 0 j)))
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(defun base64-internal-decode-string (string)
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(base64-internal-decode string (make-string (length string) 0)))
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;; (defsubst base64-decode-string! (string)
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;; (setq string (string-as-unibyte string))
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;; (base64-internal-decode string string))
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(defun base64-internal-decode-region (beg end)
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(save-excursion
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(let ((str (string-as-unibyte (buffer-substring beg end))))
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(insert
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(prog1
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(base64-internal-decode str str)
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(delete-region beg end))))))
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;; (defun base64-internal-decode-region2 (beg end)
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;; (save-excursion
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;; (let ((str (buffer-substring beg end)))
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;; (delete-region beg end)
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;; (goto-char beg)
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;; (insert (base64-decode-string! str)))))
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;; (defun base64-internal-decode-region3 (beg end)
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;; (save-excursion
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;; (let ((str (buffer-substring beg end)))
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;; (delete-region beg end)
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;; (goto-char beg)
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;; (insert (base64-internal-decode-string str)))))
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;;; @ external encoder/decoder
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;;;
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(defun base64-external-encode-region (beg end &optional no-line-break)
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(save-excursion
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(save-restriction
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(narrow-to-region beg end)
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(as-binary-process
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(apply (function call-process-region)
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beg end (car base64-external-encoder)
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t t nil
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(cdr base64-external-encoder)))
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;; for OS/2
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;; regularize line break code
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(goto-char (point-min))
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(while (re-search-forward "\r$" nil t)
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(replace-match ""))
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(if no-line-break
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(progn
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(goto-char (point-min))
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(while (search-forward "\n" nil t)
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(replace-match "")))))))
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(defun base64-external-decode-region (beg end)
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(save-excursion
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(as-binary-process
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(apply (function call-process-region)
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beg end (car base64-external-decoder)
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t t nil
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(cdr base64-external-decoder)))))
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(defun base64-external-decode-string (string)
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(with-temp-buffer
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(insert string)
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(as-binary-process
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(apply (function call-process-region)
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(point-min)(point-max) (car base64-external-decoder)
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t t nil
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(cdr base64-external-decoder)))
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(buffer-string)))
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;;; @ application interfaces
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;;;
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(defun-maybe base64-encode-region (start end &optional no-line-break)
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"Base64-encode the region between START and END.
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Return the length of the encoded text.
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Optional third argument NO-LINE-BREAK means do not break long lines
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into shorter lines.
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This function calls internal base64 encoder if size of region is
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smaller than `base64-internal-encoding-limit', otherwise it calls
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external base64 encoder specified by `base64-external-encoder'. In
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this case, you must install the program (maybe mmencode included in
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metamail or XEmacs package)."
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(interactive "*r")
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(if (and base64-internal-encoding-limit
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(> (- end start) base64-internal-encoding-limit))
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(base64-external-encode-region start end no-line-break)
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(base64-internal-encode-region start end no-line-break)))
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(defun-maybe base64-decode-region (start end)
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"Decode current region by base64.
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START and END are buffer positions.
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This function calls internal base64 decoder if size of region is
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smaller than `base64-internal-decoding-limit', otherwise it calls
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external base64 decoder specified by `base64-external-decoder'. In
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this case, you must install the program (maybe mmencode included in
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metamail or XEmacs package)."
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(interactive "*r")
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(if (and base64-internal-decoding-limit
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(> (- end start) base64-internal-decoding-limit))
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(base64-external-decode-region start end)
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(base64-internal-decode-region start end)))
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(defun-maybe base64-decode-string (string)
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"Decode STRING which is encoded in base64, and return the result.
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This function calls internal base64 decoder if size of STRING is
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smaller than `base64-internal-decoding-limit', otherwise it calls
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external base64 decoder specified by `base64-external-decoder'. In
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this case, you must install the program (maybe mmencode included in
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metamail or XEmacs package)."
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(if (and base64-internal-decoding-limit
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(> (length string) base64-internal-decoding-limit))
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(base64-external-decode-string string)
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(base64-internal-decode-string string)))
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(mel-define-method-function (mime-encode-string string (nil "base64"))
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'base64-encode-string)
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(mel-define-method-function (mime-decode-string string (nil "base64"))
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'base64-decode-string)
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(mel-define-method-function (mime-encode-region start end (nil "base64"))
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'base64-encode-region)
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(mel-define-method-function (mime-decode-region start end (nil "base64"))
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'base64-decode-region)
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(mel-define-method-function (encoded-text-encode-string string (nil "B"))
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'base64-encode-string)
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(mel-define-method encoded-text-decode-string (string (nil "B"))
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(if (string-match (eval-when-compile
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(concat "\\`" B-encoded-text-regexp "\\'"))
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string)
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(base64-decode-string string)
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(error "Invalid encoded-text %s" string)))
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(defun base64-insert-encoded-file (filename)
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"Encode contents of file FILENAME to base64, and insert the result.
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It calls external base64 encoder specified by
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`base64-external-encoder'. So you must install the program (maybe
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mmencode included in metamail or XEmacs package)."
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(interactive "*fInsert encoded file: ")
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(if (and base64-internal-encoding-limit
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(> (nth 7 (file-attributes filename))
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base64-internal-encoding-limit))
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(apply (function call-process)
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(car base64-external-encoder)
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filename t nil
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(cdr base64-external-encoder))
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(insert
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(base64-encode-string
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(with-temp-buffer
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(set-buffer-multibyte nil)
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(insert-file-contents-as-binary filename)
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(buffer-string))))
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(or (bolp) (insert ?\n))))
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(mel-define-method-function (mime-insert-encoded-file filename (nil "base64"))
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'base64-insert-encoded-file)
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(defun base64-write-decoded-region (start end filename)
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"Decode and write current region encoded by base64 into FILENAME.
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START and END are buffer positions."
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(interactive "*r\nFWrite decoded region to file: ")
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(if (and base64-internal-decoding-limit
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(> (- end start) base64-internal-decoding-limit))
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(progn
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(as-binary-process
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(apply (function call-process-region)
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start end (car base64-external-decoder)
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(null base64-external-decoder-option-to-specify-file)
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(unless base64-external-decoder-option-to-specify-file
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(list (current-buffer) nil))
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nil
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(delq nil
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(append
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(cdr base64-external-decoder)
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base64-external-decoder-option-to-specify-file
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(when base64-external-decoder-option-to-specify-file
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(list filename))))))
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(unless base64-external-decoder-option-to-specify-file
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(write-region-as-binary (point-min) (point-max) filename)))
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(let ((str (buffer-substring start end)))
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(with-temp-buffer
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(insert (base64-internal-decode-string str))
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(write-region-as-binary (point-min) (point-max) filename)))))
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(mel-define-method-function
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(mime-write-decoded-region start end filename (nil "base64"))
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'base64-write-decoded-region)
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;;; @ end
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;;;
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(provide 'mel-b-el)
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;;; mel-b-el.el ends here.
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