X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/e516799970be4553edae8ca46d5f64852befec77..937640a621a4ce2e5e56eaecca37a2a28a584318:/lisp/rot13.el

diff --git a/lisp/rot13.el b/lisp/rot13.el
index 939539b49e..bcf4252d14 100644
--- a/lisp/rot13.el
+++ b/lisp/rot13.el
@@ -1,10 +1,9 @@
-;;; rot13.el --- display a buffer in rot13.
+;;; rot13.el --- display a buffer in rot13
 
-;; Author: Howard Gayle:
-;; Maintainer: FSF
-;; Last-Modified: 16 Mar 1992
+;; Copyright (C) 1988,2002 Free Software Foundation, Inc.
 
-;; Copyright (C) 1988 Free Software Foundation, Inc.
+;; Author: Howard Gayle
+;; Maintainer: FSF
 
 ;; This file is part of GNU Emacs.
 
@@ -19,14 +18,24 @@
 ;; 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; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
 
-;; 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 Ceasar cipher encrypt/decrypt on buffers and strings, was
+;; added by Simon Josefsson.
 
 ;;; Code:
 
@@ -34,18 +43,72 @@
   (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.")
 
+(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 rot 13 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 rot 13 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 rot 13.
+
+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 rot 13 encoding for the current window."
+  (interactive)
+  (if (eq (window-display-table (selected-window)) rot13-display-table)
+      (set-window-display-table (selected-window) nil)
+    (if (null (window-display-table (selected-window)))
+	(set-window-display-table (selected-window) rot13-display-table))))
+
 (provide 'rot13)
 
+;;; arch-tag: ad5b9ca8-946c-4414-996f-e9b1bf9ec79f
 ;;; rot13.el ends here