mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-27 10:54:40 +00:00
114 lines
3.6 KiB
EmacsLisp
114 lines
3.6 KiB
EmacsLisp
;;; rot13.el --- display a buffer in rot13
|
|
|
|
;; Copyright (C) 1988,2002 Free Software Foundation, Inc.
|
|
|
|
;; Author: Howard Gayle
|
|
;; Maintainer: FSF
|
|
|
|
;; This file is part of GNU Emacs.
|
|
|
|
;; 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.
|
|
|
|
;; GNU Emacs 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.
|
|
|
|
;;; 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:
|
|
|
|
(defvar rot13-display-table
|
|
(let ((table (make-display-table))
|
|
(i 0))
|
|
(while (< i 26)
|
|
(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.
|
|
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)
|
|
|
|
;;; rot13.el ends here
|