lisp/net/tramp-uu.el

   1 ;;; tramp-uu.el --- uuencode in Lisp  -*- lexical-binding:t -*-
   2
   3 ;; Copyright (C) 2002-2018 Free Software Foundation, Inc.
   4
   5 ;; Author: Kai Großjohann <kai.grossjohann@gmx.net>
   6 ;; Maintainer: Michael Albinus <michael.albinus@gmx.de>
   7 ;; Keywords: comm, terminals
   8 ;; Package: tramp
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; An implementation of "uuencode" in Lisp.  Uses the function
  28 ;; base64-encode-region which is built-in to modern Emacsen.
  29
  30 ;;; Code:
  31
  32 (defconst tramp-uu-b64-alphabet
  33   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
  34   "Mapping from base64-encoded character to the byte it represents.")
  35
  36 (defconst tramp-uu-b64-char-to-byte
  37   (let ((i 0))
  38     (mapcar (lambda (c)
  39               (prog1
  40                   (cons c i)
  41                 (setq i (1+ i))))
  42             tramp-uu-b64-alphabet))
  43   "Alist of mapping from base64 character to its byte.")
  44
  45 (defun tramp-uu-byte-to-uu-char (byte)
  46   "Return the character encoding BYTE."
  47   (if (zerop byte) ?` (+ byte 32)))
  48
  49 (defun tramp-uu-b64-char-to-byte (char)
  50   "Return the byte that is encoded as CHAR."
  51   (cdr (assq char tramp-uu-b64-char-to-byte)))
  52
  53 ;;;###tramp-autoload
  54 (defun tramp-uuencode-region (beg end)
  55   "UU-encode the region between BEG and END."
  56   ;; First we base64 encode the region, then we transmogrify that into
  57   ;; uu encoding.
  58   (let ((len (base64-encode-region beg end t))
  59         i c)
  60     (save-excursion
  61       (goto-char beg)
  62       (setq i 0)
  63       (while (< i len)
  64         (setq c (char-after (point)))
  65         (delete-char 1)
  66         (if (equal c ?=)
  67             ;; "=" means padding.  Insert "`" instead.  Not counted for length.
  68             (progn (insert "`") (setq len (1- len)))
  69           (insert (tramp-uu-byte-to-uu-char (tramp-uu-b64-char-to-byte c)))
  70           (setq i (1+ i)))
  71         ;; Every 60 characters, add "M" at beginning of line (as
  72         ;; length byte) and insert a newline.
  73         (when (zerop (% i 60))
  74           (save-excursion
  75             (beginning-of-line)
  76             (insert (char-to-string (+ 32 (/ (* 3 60) 4)))))
  77           (insert "\n")))
  78       ;; If there is something leftover, we compute the length byte
  79       ;; for that stuff and insert it and a trailing newline.
  80       (unless (zerop (% i 60))
  81         (save-excursion
  82           (beginning-of-line)
  83           (insert (char-to-string (+ 32 (% (- end beg) 45)))))
  84         (insert "\n"))
  85       ;; Why is there always a "`" line at the end?
  86       (insert "`\nend\n")
  87       (goto-char beg)
  88       (insert "begin 600 xxx\n"))))
  89
  90 (add-hook 'tramp-unload-hook
  91           (lambda ()
  92             (unload-feature 'tramp-uu 'force)))
  93
  94 (provide 'tramp-uu)
  95
  96 ;;; tramp-uu.el ends here
  97
  98 ;; Local Variables:
  99 ;; mode: Emacs-Lisp
 100 ;; coding: utf-8
 101 ;; End: