Commit | Line | Data |
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55535639 | 1 | ;;; rot13.el --- display a buffer in rot13 |
c88ab9ce | 2 | |
aaef169d TTN |
3 | ;; Copyright (C) 1988, 2002, 2003, 2004, 2005, |
4 | ;; 2006 Free Software Foundation, Inc. | |
9750e079 | 5 | |
55535639 | 6 | ;; Author: Howard Gayle |
e5167999 | 7 | ;; Maintainer: FSF |
3b4a6e27 JB |
8 | |
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
e5167999 | 13 | ;; the Free Software Foundation; either version 2, or (at your option) |
3b4a6e27 JB |
14 | ;; any later version. |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
b578f267 | 22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
086add15 LK |
23 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
24 | ;; Boston, MA 02110-1301, USA. | |
3b4a6e27 | 25 | |
07b3798c | 26 | ;;; Commentary: |
3b4a6e27 | 27 | |
280b8e59 | 28 | ;; The entry point, `rot13-other-window', performs a Caesar cipher |
f1180544 | 29 | ;; encrypt/decrypt on the current buffer and displays the result in another |
716e9939 | 30 | ;; window. Rot13 encryption is sometimes used on USENET as a read-at-your- |
d9ecc911 ER |
31 | ;; own-risk wrapper for material some might consider offensive, such as |
32 | ;; ethnic humor. | |
33 | ;; | |
716e9939 | 34 | ;; Written by Howard Gayle. |
3b4a6e27 | 35 | ;; This hack is mainly to show off the char table stuff. |
280b8e59 SJ |
36 | ;; |
37 | ;; New entry points, `rot13', `rot13-string', and `rot13-region' that | |
38 | ;; performs Ceasar cipher encrypt/decrypt on buffers and strings, was | |
39 | ;; added by Simon Josefsson. | |
3b4a6e27 | 40 | |
e5167999 ER |
41 | ;;; Code: |
42 | ||
3b4a6e27 JB |
43 | (defvar rot13-display-table |
44 | (let ((table (make-display-table)) | |
45 | (i 0)) | |
46 | (while (< i 26) | |
342df1e2 RS |
47 | (aset table (+ i ?a) (vector (+ (% (+ i 13) 26) ?a))) |
48 | (aset table (+ i ?A) (vector (+ (% (+ i 13) 26) ?A))) | |
3b4a6e27 JB |
49 | (setq i (1+ i))) |
50 | table) | |
51 | "Char table for rot 13 display.") | |
52 | ||
280b8e59 SJ |
53 | (defvar rot13-translate-table |
54 | (let ((str (make-string 127 0)) | |
55 | (i 0)) | |
56 | (while (< i 127) | |
57 | (aset str i i) | |
58 | (setq i (1+ i))) | |
59 | (setq i 0) | |
60 | (while (< i 26) | |
61 | (aset str (+ i ?a) (+ (% (+ i 13) 26) ?a)) | |
62 | (aset str (+ i ?A) (+ (% (+ i 13) 26) ?A)) | |
63 | (setq i (1+ i))) | |
64 | str) | |
65 | "String table for rot 13 translation.") | |
66 | ||
67 | ;;;###autoload | |
68 | (defun rot13 (object &optional start end) | |
69 | "Return Rot13 encryption of OBJECT, a buffer or string." | |
70 | (if (bufferp object) | |
71 | (with-current-buffer object | |
72 | (rot13-region start end)) | |
73 | (rot13-string object))) | |
74 | ||
75 | ;;;###autoload | |
76 | (defun rot13-string (string) | |
77 | "Return Rot13 encryption of STRING." | |
78 | (with-temp-buffer | |
79 | (insert string) | |
80 | (rot13-region (point-min) (point-max)) | |
81 | (buffer-string))) | |
82 | ||
83 | ;;;###autoload | |
84 | (defun rot13-region (start end) | |
85 | "Rot13 encrypt the region between START and END in current buffer." | |
86 | (interactive "r") | |
87 | (translate-region start end rot13-translate-table)) | |
88 | ||
8931b34a | 89 | ;;;###autoload |
3b4a6e27 | 90 | (defun rot13-other-window () |
7d002ae1 | 91 | "Display current buffer in rot 13 in another window. |
c8c6b45a EZ |
92 | The text itself is not modified, only the way it is displayed is affected. |
93 | ||
94 | To terminate the rot13 display, delete that window. As long as that window | |
95 | is not deleted, any buffer displayed in it will become instantly encoded | |
96 | in rot 13. | |
97 | ||
1604ce98 | 98 | See also `toggle-rot13-mode'." |
3b4a6e27 JB |
99 | (interactive) |
100 | (let ((w (display-buffer (current-buffer) t))) | |
101 | (set-window-display-table w rot13-display-table))) | |
102 | ||
dcd12c89 RS |
103 | ;;;###autoload |
104 | (defun toggle-rot13-mode () | |
105 | "Toggle the use of rot 13 encoding for the current window." | |
106 | (interactive) | |
107 | (if (eq (window-display-table (selected-window)) rot13-display-table) | |
108 | (set-window-display-table (selected-window) nil) | |
109 | (if (null (window-display-table (selected-window))) | |
110 | (set-window-display-table (selected-window) rot13-display-table)))) | |
111 | ||
3b4a6e27 | 112 | (provide 'rot13) |
c88ab9ce | 113 | |
ab5796a9 | 114 | ;;; arch-tag: ad5b9ca8-946c-4414-996f-e9b1bf9ec79f |
c88ab9ce | 115 | ;;; rot13.el ends here |