-;;; rot13.el --- display a buffer in rot13.
+;;; rot13.el --- display a buffer in ROT13
-;; Copyright (C) 1988 Free Software Foundation, Inc.
+;; Copyright (C) 1988, 2001-2016 Free Software Foundation, Inc.
-;; Author: Howard Gayle:
-;; Maintainer: FSF
+;; Author: Howard Gayle
+;; Maintainer: emacs-devel@gnu.org
;; This file is part of GNU Emacs.
-;; GNU Emacs is free software; you can redistribute it and/or modify
+;; GNU Emacs 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.
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; 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, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
-;; Commentary:
-
-;; Written by Howard Gayle. See case-table.el for details.
+;;; Commentary:
+;; The entry point, `rot13-other-window', performs a Caesar cipher
+;; encrypt/decrypt on the current buffer and displays the result in another
+;; window. ROT13 encryption is sometimes used on USENET as a read-at-your-
+;; own-risk wrapper for material some might consider offensive, such as
+;; ethnic humor.
+;;
+;; Written by Howard Gayle.
;; This hack is mainly to show off the char table stuff.
+;;
+;; New entry points, `rot13', `rot13-string', and `rot13-region' that
+;; performs Caesar cipher encrypt/decrypt on buffers and strings, was
+;; added by Simon Josefsson.
;;; Code:
(let ((table (make-display-table))
(i 0))
(while (< i 26)
- (aset table (+ i ?a) (make-rope (+ (% (+ i 13) 26) ?a)))
- (aset table (+ i ?A) (make-rope (+ (% (+ i 13) 26) ?A)))
+ (aset table (+ i ?a) (vector (+ (% (+ i 13) 26) ?a)))
+ (aset table (+ i ?A) (vector (+ (% (+ i 13) 26) ?A)))
(setq i (1+ i)))
table)
- "Char table for rot 13 display.")
+ "Char table for ROT13 display.")
+
+(defvar rot13-translate-table
+ (let ((str (make-string 127 0))
+ (i 0))
+ (while (< i 127)
+ (aset str i i)
+ (setq i (1+ i)))
+ (setq i 0)
+ (while (< i 26)
+ (aset str (+ i ?a) (+ (% (+ i 13) 26) ?a))
+ (aset str (+ i ?A) (+ (% (+ i 13) 26) ?A))
+ (setq i (1+ i)))
+ str)
+ "String table for ROT13 translation.")
+
+;;;###autoload
+(defun rot13 (object &optional start end)
+ "Return ROT13 encryption of OBJECT, a buffer or string."
+ (if (bufferp object)
+ (with-current-buffer object
+ (rot13-region start end))
+ (rot13-string object)))
+;;;###autoload
+(defun rot13-string (string)
+ "Return ROT13 encryption of STRING."
+ (with-temp-buffer
+ (insert string)
+ (rot13-region (point-min) (point-max))
+ (buffer-string)))
+
+;;;###autoload
+(defun rot13-region (start end)
+ "ROT13 encrypt the region between START and END in current buffer."
+ (interactive "r")
+ (translate-region start end rot13-translate-table))
+
+;;;###autoload
(defun rot13-other-window ()
- "Display current buffer in rot 13 in another window."
+ "Display current buffer in ROT13 in another window.
+The text itself is not modified, only the way it is displayed is affected.
+
+To terminate the ROT13 display, delete that window. As long as that window
+is not deleted, any buffer displayed in it will become instantly encoded
+in ROT13.
+
+See also `toggle-rot13-mode'."
(interactive)
(let ((w (display-buffer (current-buffer) t)))
(set-window-display-table w rot13-display-table)))
+;;;###autoload
+(defun toggle-rot13-mode ()
+ "Toggle the use of ROT13 encoding for the current window."
+ (interactive)
+ (if (eq (window-display-table) rot13-display-table)
+ (set-window-display-table (selected-window) nil)
+ (if (null (window-display-table))
+ (set-window-display-table (selected-window) rot13-display-table))))
+
(provide 'rot13)
;;; rot13.el ends here