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emacs/lisp/net/tramp-uu.el
2022-01-01 02:45:51 -05:00

97 lines
3.0 KiB
EmacsLisp

;;; tramp-uu.el --- uuencode in Lisp -*- lexical-binding:t -*-
;; Copyright (C) 2002-2022 Free Software Foundation, Inc.
;; Author: Kai Großjohann <kai.grossjohann@gmx.net>
;; Maintainer: Michael Albinus <michael.albinus@gmx.de>
;; Keywords: comm, terminals
;; Package: tramp
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; An implementation of "uuencode" in Lisp. Uses the function
;; base64-encode-region which is built-in to modern Emacsen.
;;; Code:
(defconst tramp-uu-b64-alphabet
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
"Mapping from base64-encoded character to the byte it represents.")
(defconst tramp-uu-b64-char-to-byte
(let ((i 0))
(mapcar (lambda (c)
(prog1
(cons c i)
(setq i (1+ i))))
tramp-uu-b64-alphabet))
"Alist of mapping from base64 character to its byte.")
(defun tramp-uu-byte-to-uu-char (byte)
"Return the character encoding BYTE."
(if (zerop byte) ?` (+ byte 32)))
(defun tramp-uu-b64-char-to-byte (char)
"Return the byte that is encoded as CHAR."
(cdr (assq char tramp-uu-b64-char-to-byte)))
;;;###tramp-autoload
(defun tramp-uuencode-region (beg end)
"UU-encode the region between BEG and END."
;; First we base64 encode the region, then we transmogrify that into
;; uu encoding.
(let ((len (base64-encode-region beg end t))
i c)
(save-excursion
(goto-char beg)
(setq i 0)
(while (< i len)
(setq c (char-after (point)))
(delete-char 1)
(if (equal c ?=)
;; "=" means padding. Insert "`" instead. Not counted for length.
(progn (insert "`") (setq len (1- len)))
(insert (tramp-uu-byte-to-uu-char (tramp-uu-b64-char-to-byte c)))
(setq i (1+ i)))
;; Every 60 characters, add "M" at beginning of line (as
;; length byte) and insert a newline.
(when (zerop (% i 60))
(save-excursion
(beginning-of-line)
(insert (char-to-string (+ 32 (/ (* 3 60) 4)))))
(insert "\n")))
;; If there is something leftover, we compute the length byte
;; for that stuff and insert it and a trailing newline.
(unless (zerop (% i 60))
(save-excursion
(beginning-of-line)
(insert (char-to-string (+ 32 (% (- end beg) 45)))))
(insert "\n"))
;; Why is there always a "`" line at the end?
(insert "`\nend\n")
(goto-char beg)
(insert "begin 600 xxx\n"))))
(add-hook 'tramp-unload-hook
(lambda ()
(unload-feature 'tramp-uu 'force)))
(provide 'tramp-uu)
;;; tramp-uu.el ends here