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;;; yenc.el --- elisp native yenc decoder |
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;; Copyright (c) 2002 Free Software Foundation, Inc. |
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;; Author: Jesper Harder <harder@ifa.au.dk> |
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;; Keywords: yenc news |
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;; This file is part of GNU Emacs. |
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;; GNU Emacs is free software; you can redistribute it and/or modify |
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;; it under the terms of the GNU General Public License as published by |
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;; the Free Software Foundation; either version 2, or (at your option) |
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;; any later version. |
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;; GNU Emacs is distributed in the hope that it will be useful, |
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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;; GNU General Public License for more details. |
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;; You should have received a copy of the GNU General Public License |
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;; along with GNU Emacs; see the file COPYING. If not, write to the |
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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;; Boston, MA 02111-1307, USA. |
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;;; Commentary: |
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;; Functions for decoding yenc encoded messages. |
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;; |
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;; Limitations: |
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;; |
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;; * Does not handle multipart messages. |
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;; * No support for external decoders. |
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;; * Doesn't check the crc32 checksum (if present). |
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;;; Code: |
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(eval-when-compile (require 'cl)) |
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(defconst yenc-begin-line |
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"^=ybegin.*$") |
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(defconst yenc-decoding-vector |
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[214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 |
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231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 |
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248 249 250 251 252 253 254 255 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
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16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 |
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39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 |
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62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 |
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85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 |
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106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 |
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123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 |
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140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 |
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157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 |
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174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 |
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191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 |
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208 209 210 211 212 213]) |
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;;;###autoload |
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(defun yenc-decode-region (start end) |
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"Yenc decode region between START and END using an internal decoder." |
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(interactive "r") |
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(let (work-buffer) |
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(unwind-protect |
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(save-excursion |
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(goto-char start) |
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(when (re-search-forward yenc-begin-line end t) |
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(let ((first (match-end 0)) |
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(header-alist (yenc-parse-line (match-string 0))) |
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bytes last footer-alist char) |
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(when (re-search-forward "^=ypart.*$" end t) |
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(setq first (match-end 0))) |
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(when (re-search-forward "^=yend.*$" end t) |
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(setq last (match-beginning 0)) |
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(setq footer-alist (yenc-parse-line (match-string 0))) |
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(let (default-enable-multibyte-characters) |
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(setq work-buffer (generate-new-buffer " *yenc-work*"))) |
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(while (< first last) |
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(setq char (char-after first)) |
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(cond ((or (eq char ?\r) |
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(eq char ?\n))) |
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((eq char ?=) |
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(setq char (char-after (incf first))) |
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(with-current-buffer work-buffer |
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(insert-char (mod (- char 106) 256) 1))) |
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(t |
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(with-current-buffer work-buffer |
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;;(insert-char (mod (- char 42) 256) 1) |
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(insert-char (aref yenc-decoding-vector char) 1)))) |
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(incf first)) |
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(setq bytes (buffer-size work-buffer)) |
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(unless (and (= (cdr (assq 'size header-alist)) bytes) |
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(= (cdr (assq 'size footer-alist)) bytes)) |
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(message "Warning: Size mismatch while decoding.")) |
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(goto-char start) |
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(delete-region start end) |
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(insert-buffer-substring work-buffer)))) |
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(and work-buffer (kill-buffer work-buffer)))))) |
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;;;###autoload |
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(defun yenc-extract-filename () |
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"Extract file name from an yenc header." |
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(save-excursion |
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(when (re-search-forward yenc-begin-line nil t) |
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(cdr (assoc 'name (yenc-parse-line (match-string 0))))))) |
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(defun yenc-parse-line (str) |
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"Extract file name and size from STR." |
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(let (result name) |
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(when (string-match "^=y.*size=\\([0-9]+\\)" str) |
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(push (cons 'size (string-to-number (match-string 1 str))) result)) |
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(when (string-match "^=y.*name=\\(.*\\)$" str) |
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(setq name (match-string 1 str)) |
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;; Remove trailing white space |
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(when (string-match " +$" name) |
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(setq name (substring name 0 (match-beginning 0)))) |
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(push (cons 'name name) result)) |
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result)) |
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(provide 'yenc) |
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;;; arch-tag: 74df17e8-6fa8-4071-9f7d-54d548d79d9a |
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;;; yenc.el ends here |