Commit | Line | Data |
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52490bfc | 1 | ;;; rot13.el --- display a buffer in ROT13 |
c88ab9ce | 2 | |
c90f2757 | 3 | ;; Copyright (C) 1988, 2001, 2002, 2003, 2004, 2005, |
409cc4a3 | 4 | ;; 2006, 2007, 2008 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 | ||
eb3fa2cf | 11 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
3b4a6e27 | 12 | ;; it under the terms of the GNU General Public License as published by |
eb3fa2cf GM |
13 | ;; the Free Software Foundation, either version 3 of the License, or |
14 | ;; (at your option) any later version. | |
3b4a6e27 JB |
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 | |
eb3fa2cf | 22 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
3b4a6e27 | 23 | |
07b3798c | 24 | ;;; Commentary: |
3b4a6e27 | 25 | |
280b8e59 | 26 | ;; The entry point, `rot13-other-window', performs a Caesar cipher |
f1180544 | 27 | ;; encrypt/decrypt on the current buffer and displays the result in another |
52490bfc | 28 | ;; window. ROT13 encryption is sometimes used on USENET as a read-at-your- |
d9ecc911 ER |
29 | ;; own-risk wrapper for material some might consider offensive, such as |
30 | ;; ethnic humor. | |
31 | ;; | |
716e9939 | 32 | ;; Written by Howard Gayle. |
3b4a6e27 | 33 | ;; This hack is mainly to show off the char table stuff. |
280b8e59 SJ |
34 | ;; |
35 | ;; New entry points, `rot13', `rot13-string', and `rot13-region' that | |
36 | ;; performs Ceasar cipher encrypt/decrypt on buffers and strings, was | |
37 | ;; added by Simon Josefsson. | |
3b4a6e27 | 38 | |
e5167999 ER |
39 | ;;; Code: |
40 | ||
3b4a6e27 JB |
41 | (defvar rot13-display-table |
42 | (let ((table (make-display-table)) | |
43 | (i 0)) | |
44 | (while (< i 26) | |
342df1e2 RS |
45 | (aset table (+ i ?a) (vector (+ (% (+ i 13) 26) ?a))) |
46 | (aset table (+ i ?A) (vector (+ (% (+ i 13) 26) ?A))) | |
3b4a6e27 JB |
47 | (setq i (1+ i))) |
48 | table) | |
52490bfc | 49 | "Char table for ROT13 display.") |
3b4a6e27 | 50 | |
280b8e59 SJ |
51 | (defvar rot13-translate-table |
52 | (let ((str (make-string 127 0)) | |
53 | (i 0)) | |
54 | (while (< i 127) | |
55 | (aset str i i) | |
56 | (setq i (1+ i))) | |
57 | (setq i 0) | |
58 | (while (< i 26) | |
59 | (aset str (+ i ?a) (+ (% (+ i 13) 26) ?a)) | |
60 | (aset str (+ i ?A) (+ (% (+ i 13) 26) ?A)) | |
61 | (setq i (1+ i))) | |
62 | str) | |
52490bfc | 63 | "String table for ROT13 translation.") |
280b8e59 SJ |
64 | |
65 | ;;;###autoload | |
66 | (defun rot13 (object &optional start end) | |
52490bfc | 67 | "Return ROT13 encryption of OBJECT, a buffer or string." |
280b8e59 SJ |
68 | (if (bufferp object) |
69 | (with-current-buffer object | |
70 | (rot13-region start end)) | |
71 | (rot13-string object))) | |
72 | ||
73 | ;;;###autoload | |
74 | (defun rot13-string (string) | |
52490bfc | 75 | "Return ROT13 encryption of STRING." |
280b8e59 SJ |
76 | (with-temp-buffer |
77 | (insert string) | |
78 | (rot13-region (point-min) (point-max)) | |
79 | (buffer-string))) | |
80 | ||
81 | ;;;###autoload | |
82 | (defun rot13-region (start end) | |
52490bfc | 83 | "ROT13 encrypt the region between START and END in current buffer." |
280b8e59 SJ |
84 | (interactive "r") |
85 | (translate-region start end rot13-translate-table)) | |
86 | ||
8931b34a | 87 | ;;;###autoload |
3b4a6e27 | 88 | (defun rot13-other-window () |
52490bfc | 89 | "Display current buffer in ROT13 in another window. |
c8c6b45a EZ |
90 | The text itself is not modified, only the way it is displayed is affected. |
91 | ||
52490bfc | 92 | To terminate the ROT13 display, delete that window. As long as that window |
c8c6b45a | 93 | is not deleted, any buffer displayed in it will become instantly encoded |
52490bfc | 94 | in ROT13. |
c8c6b45a | 95 | |
1604ce98 | 96 | See also `toggle-rot13-mode'." |
3b4a6e27 JB |
97 | (interactive) |
98 | (let ((w (display-buffer (current-buffer) t))) | |
99 | (set-window-display-table w rot13-display-table))) | |
100 | ||
dcd12c89 RS |
101 | ;;;###autoload |
102 | (defun toggle-rot13-mode () | |
52490bfc | 103 | "Toggle the use of ROT13 encoding for the current window." |
dcd12c89 RS |
104 | (interactive) |
105 | (if (eq (window-display-table (selected-window)) rot13-display-table) | |
106 | (set-window-display-table (selected-window) nil) | |
107 | (if (null (window-display-table (selected-window))) | |
108 | (set-window-display-table (selected-window) rot13-display-table)))) | |
109 | ||
3b4a6e27 | 110 | (provide 'rot13) |
c88ab9ce | 111 | |
cbee283d | 112 | ;; arch-tag: ad5b9ca8-946c-4414-996f-e9b1bf9ec79f |
c88ab9ce | 113 | ;;; rot13.el ends here |