--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lisp/apel/mule-caesar.el	Mon Aug 13 09:39:39 2007 +0200
@@ -0,0 +1,94 @@
+;;; mule-caesar.el --- ROT 13-47 Caesar rotation utility
+
+;; Copyright (C) 1997 Free Software Foundation, Inc.
+
+;; Author: MORIOKA Tomohiko <morioka@jaist.ac.jp>
+;; Version: $Id: mule-caesar.el,v 1.1 1997/06/03 04:18:36 steve Exp $
+;; Keywords: ROT 13-47, caesar, mail, news, text/x-rot13-47
+
+;; This file is part of APEL (A Portable Emacs 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:
+
+(defun char-to-octet-list (character)
+  "Return list of octets in code table of graphic character set."
+  (let* ((code (char-int character))
+	 (dim (charset-dimension (char-charset code)))
+	 dest)
+    (while (> dim 0)
+      (setq dest (cons (logand code 127) dest)
+	    dim (1- dim)
+	    code (lsh code -7))
+      )
+    dest))
+
+(defun mule-caesar-region (start end &optional stride-ascii)
+  "Caesar rotation of current region.
+Optional argument STRIDE-ASCII is rotation-size for Latin alphabet
+\(A-Z and a-z).  For non-ASCII text, ROT-N/2 will be performed in any
+case (N=charset-chars; 94 for 94 or 94x94 graphic character set; 96
+for 96 or 96x96 graphic character set)."
+  (interactive "r\nP")
+  (setq stride-ascii (if stride-ascii
+			 (mod stride-ascii 26)
+		       13))
+  (save-excursion
+    (save-restriction
+      (narrow-to-region start end)
+      (goto-char start)
+      (while (< (point)(point-max))
+	(let* ((chr (char-after (point)))
+	       (charset (char-charset chr))
+	       )
+	  (if (eq charset 'ascii)
+	      (cond ((and (<= ?A chr) (<= chr ?Z))
+		     (setq chr (+ chr stride-ascii))
+		     (if (> chr ?Z)
+			 (setq chr (- chr 26))
+		       )
+		     (delete-char 1)
+		     (insert chr)
+		     )
+		    ((and (<= ?a chr) (<= chr ?z))
+		     (setq chr (+ chr stride-ascii))
+		     (if (> chr ?z)
+			 (setq chr (- chr 26))
+		       )
+		     (delete-char 1)
+		     (insert chr)
+		     )
+		    (t
+		     (forward-char)
+		     ))
+	    (let* ((stride (lsh (charset-chars charset) -1))
+		   (ret (mapcar (function
+				 (lambda (octet)
+				   (if (< octet 80)
+				       (+ octet stride)
+				     (- octet stride)
+				     )))
+				(char-to-octet-list chr))))
+	      (delete-char 1)
+	      (insert (make-char (char-charset chr)
+				 (car ret)(car (cdr ret))))
+	      )))))))
+  
+
+(provide 'mule-caesar)
+
+;;; mule-caesar.el ends here