lisp/net/tramp-uu.el

   1 ;;; tramp-uu.el --- uuencode in Lisp
   2
   3 ;; Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007,
   4 ;;   2008 Free Software Foundation, Inc.
   5
   6 ;; Author: Kai Großjohann <kai.grossjohann@gmx.net>
   7 ;; Keywords: comm, terminals
   8
   9 ;; This file is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 3, or (at your option)
  12 ;; any later version.
  13
  14 ;; This file is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, see
  21 ;; <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; An implementation of "uuencode" in Lisp.  Uses the function
  26 ;; base64-encode-region which is built-in to modern Emacsen.
  27
  28 ;;; Code:
  29
  30 (defvar tramp-uu-b64-alphabet
  31   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
  32   "Mapping from base64-encoded character to the byte it represents.")
  33
  34 (defvar tramp-uu-b64-char-to-byte
  35   (let ((i 0))
  36     (mapcar (lambda (c)
  37               (prog1
  38                   (cons c i)
  39                 (setq i (1+ i))))
  40             tramp-uu-b64-alphabet))
  41   "Alist of mapping from base64 character to its byte.")
  42
  43 (defun tramp-uu-byte-to-uu-char (byte)
  44   "Return the character encoding BYTE."
  45   (if (zerop byte) ?` (+ byte 32)))
  46
  47 (defun tramp-uu-b64-char-to-byte (char)
  48   "Return the byte that is encoded as CHAR."
  49   (cdr (assq char tramp-uu-b64-char-to-byte)))
  50
  51 (defun tramp-uuencode-region (beg end)
  52   "UU-encode the region between BEG and END."
  53   ;; First we base64 encode the region, then we transmogrify that into
  54   ;; uu encoding.
  55   (let ((len (base64-encode-region beg end t))
  56         (padding 0)
  57         i c)
  58     (save-excursion
  59       (goto-char beg)
  60       (setq i 0)
  61       (while (< i len)
  62         (setq c (char-after (point)))
  63         (delete-char 1)
  64         (if (equal c ?=)
  65             ;; "=" means padding.  Insert "`" instead.  Not counted for length.
  66             (progn (insert "`") (setq len (1- len)))
  67           (insert (tramp-uu-byte-to-uu-char (tramp-uu-b64-char-to-byte c)))
  68           (setq i (1+ i)))
  69         ;; Every 60 characters, add "M" at beginning of line (as
  70         ;; length byte) and insert a newline.
  71         (when (zerop (% i 60))
  72           (save-excursion
  73             (beginning-of-line)
  74             (insert (char-to-string (+ 32 (/ (* 3 60) 4)))))
  75           (insert "\n")))
  76       ;; If there is something leftover, we compute the length byte
  77       ;; for that stuff and insert it and a trailing newline.
  78       (unless (zerop (% i 60))
  79         (save-excursion
  80           (beginning-of-line)
  81           (insert (char-to-string (+ 32 (% (- end beg) 45)))))
  82         (insert "\n"))
  83       ;; Why is there always a "`" line at the end?
  84       (insert "`\nend\n")
  85       (goto-char beg)
  86       (insert "begin 600 xxx\n"))))
  87
  88 (provide 'tramp-uu)
  89
  90 ;; arch-tag: 7153f2c6-8be5-4cd2-8c06-0fbcf5190ef6
  91 ;;; tramp-uu.el ends here
  92
  93 ;; Local Variables:
  94 ;; mode: Emacs-Lisp
  95 ;; coding: utf-8
  96 ;; End: