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23f87bed | 1 | ;;; yenc.el --- elisp native yenc decoder |
e84b4b86 | 2 | |
d7a0267c | 3 | ;; Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. |
23f87bed MB |
4 | |
5 | ;; Author: Jesper Harder <harder@ifa.au.dk> | |
6 | ;; Keywords: yenc news | |
7 | ||
8 | ;; This file is part of GNU Emacs. | |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
12 | ;; the Free Software Foundation; either version 2, or (at your option) | |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
3a35cf56 LK |
22 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
23 | ;; Boston, MA 02110-1301, USA. | |
23f87bed MB |
24 | |
25 | ;;; Commentary: | |
26 | ||
27 | ;; Functions for decoding yenc encoded messages. | |
28 | ;; | |
29 | ;; Limitations: | |
30 | ;; | |
31 | ;; * Does not handle multipart messages. | |
32 | ;; * No support for external decoders. | |
33 | ;; * Doesn't check the crc32 checksum (if present). | |
34 | ||
35 | ;;; Code: | |
36 | ||
37 | (eval-when-compile (require 'cl)) | |
38 | ||
39 | (defconst yenc-begin-line | |
40 | "^=ybegin.*$") | |
41 | ||
42 | (defconst yenc-decoding-vector | |
43 | [214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 | |
44 | 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 | |
45 | 248 249 250 251 252 253 254 255 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | |
46 | 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | |
47 | 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | |
48 | 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | |
49 | 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | |
50 | 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 | |
51 | 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 | |
52 | 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 | |
53 | 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 | |
54 | 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 | |
55 | 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | |
56 | 208 209 210 211 212 213]) | |
57 | ||
58 | ;;;###autoload | |
59 | (defun yenc-decode-region (start end) | |
60 | "Yenc decode region between START and END using an internal decoder." | |
61 | (interactive "r") | |
62 | (let (work-buffer) | |
63 | (unwind-protect | |
64 | (save-excursion | |
65 | (goto-char start) | |
66 | (when (re-search-forward yenc-begin-line end t) | |
67 | (let ((first (match-end 0)) | |
68 | (header-alist (yenc-parse-line (match-string 0))) | |
69 | bytes last footer-alist char) | |
70 | (when (re-search-forward "^=ypart.*$" end t) | |
71 | (setq first (match-end 0))) | |
72 | (when (re-search-forward "^=yend.*$" end t) | |
73 | (setq last (match-beginning 0)) | |
74 | (setq footer-alist (yenc-parse-line (match-string 0))) | |
75 | (let (default-enable-multibyte-characters) | |
76 | (setq work-buffer (generate-new-buffer " *yenc-work*"))) | |
77 | (while (< first last) | |
78 | (setq char (char-after first)) | |
79 | (cond ((or (eq char ?\r) | |
80 | (eq char ?\n))) | |
81 | ((eq char ?=) | |
82 | (setq char (char-after (incf first))) | |
83 | (with-current-buffer work-buffer | |
84 | (insert-char (mod (- char 106) 256) 1))) | |
85 | (t | |
86 | (with-current-buffer work-buffer | |
87 | ;;(insert-char (mod (- char 42) 256) 1) | |
88 | (insert-char (aref yenc-decoding-vector char) 1)))) | |
89 | (incf first)) | |
90 | (setq bytes (buffer-size work-buffer)) | |
91 | (unless (and (= (cdr (assq 'size header-alist)) bytes) | |
92 | (= (cdr (assq 'size footer-alist)) bytes)) | |
93 | (message "Warning: Size mismatch while decoding.")) | |
94 | (goto-char start) | |
95 | (delete-region start end) | |
96 | (insert-buffer-substring work-buffer)))) | |
97 | (and work-buffer (kill-buffer work-buffer)))))) | |
98 | ||
99 | ;;;###autoload | |
100 | (defun yenc-extract-filename () | |
101 | "Extract file name from an yenc header." | |
102 | (save-excursion | |
103 | (when (re-search-forward yenc-begin-line nil t) | |
104 | (cdr (assoc 'name (yenc-parse-line (match-string 0))))))) | |
105 | ||
106 | (defun yenc-parse-line (str) | |
107 | "Extract file name and size from STR." | |
108 | (let (result name) | |
109 | (when (string-match "^=y.*size=\\([0-9]+\\)" str) | |
110 | (push (cons 'size (string-to-number (match-string 1 str))) result)) | |
111 | (when (string-match "^=y.*name=\\(.*\\)$" str) | |
112 | (setq name (match-string 1 str)) | |
113 | ;; Remove trailing white space | |
114 | (when (string-match " +$" name) | |
115 | (setq name (substring name 0 (match-beginning 0)))) | |
116 | (push (cons 'name name) result)) | |
117 | result)) | |
118 | ||
119 | (provide 'yenc) | |
120 | ||
121 | ;;; arch-tag: 74df17e8-6fa8-4071-9f7d-54d548d79d9a | |
122 | ;;; yenc.el ends here |