punycode.el

   1 ;;; punycode.el --- An ASCII compatible Unicode encoding format.
   2
   3 ;; Copyright (C) 2003  Simon Josefsson
   4 ;; Keywords: punycode, idna, idn, unicode, encoding
   5
   6 ;; This file is part of GNU Libidn.
   7
   8 ;; GNU Libidn is free software; you can redistribute it and/or modify
   9 ;; it under the terms of the GNU General Public License as published by
  10 ;; the Free Software Foundation; either version 2, or (at your option)
  11 ;; any later version.
  12
  13 ;; GNU Libidn is distributed in the hope that it will be useful,
  14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;; GNU General Public License for more details.
  17
  18 ;; You should have received a copy of the GNU General Public License
  19 ;; along with GNU Libidn; see the file COPYING.  If not, write to the
  20 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21 ;; Boston, MA 02111-1307, USA.
  22
  23 ;;; Commentary:
  24
  25 ;; A simple wrapper around the command line "idn" utility in GNU
  26 ;; Libidn to make punycode operations available in Emacs.
  27
  28 ;; Example:
  29 ;;
  30 ;; (punycode-encode "räksmörgås")
  31 ;; => "rksmrgs-5wao1o"
  32 ;;
  33 ;; (punycode-encode "foo")
  34 ;; => "foo-"
  35 ;;
  36 ;; (punycode-decode "rksmrgs-5wao1o")
  37 ;; => "räksmörgås"
  38 ;;
  39 ;; (punycode-decode "foo-")
  40 ;; => "foo"
  41
  42 ;; This package is useless unless your emacs has at least partial
  43 ;; support for the UTF-8 coding system.
  44
  45 ;; Report bugs to bug-libidn@gnu.org.
  46
  47 ;;; Code:
  48
  49 (defgroup punycode nil
  50   "Punycode: An ASCII compatible Unicode encoding format.")
  51
  52 (defcustom punycode-program "env CHARSET=UTF-8 idn"
  53   "Name of the GNU Libidn \"idn\" application."
  54   :type 'string
  55   :group 'punycode)
  56
  57 (defcustom punycode-encode-parameters "--quiet --punycode-encode"
  58   "Parameters passed to `punycode-program' to invoke punycode encoding mode."
  59   :type 'string
  60   :group 'punycode)
  61
  62 (defcustom punycode-decode-parameters "--quiet --punycode-decode"
  63   "Parameters passed to `punycode-program' to invoke punycode decoding mode."
  64   :type 'string
  65   :group 'punycode)
  66
  67 ;; Internal process handling:
  68
  69 (defvar punycode-encode-process nil
  70   "Internal variable holding process for punycode encoding.")
  71 (defvar punycode-encode-response nil
  72   "Internal variable holding response data received from punycode process.")
  73
  74 (defun punycode-encode-response-clear ()
  75   (setq punycode-encode-response nil))
  76
  77 (defun punycode-encode-response ()
  78   (while (and (eq (process-status punycode-encode-process) 'run)
  79               (null punycode-encode-response))
  80     (accept-process-output punycode-encode-process 1))
  81   punycode-encode-response)
  82
  83 (defun punycode-encode-filter (process string)
  84   (setq punycode-encode-response (concat punycode-encode-response string)))
  85
  86 (defun punycode-encode-process ()
  87   (if (and punycode-encode-process
  88            (eq (process-status punycode-encode-process) 'run))
  89       punycode-encode-process
  90     (if punycode-encode-process
  91         (condition-case ()
  92             (kill-process punycode-encode-process)
  93           (error)))
  94     (when (setq punycode-encode-process
  95                 (start-process "punycode" nil
  96                                shell-file-name shell-command-switch
  97                                (concat punycode-program " "
  98                                        punycode-encode-parameters)))
  99       (set-process-filter punycode-encode-process 'punycode-encode-filter)
 100       (set-process-coding-system punycode-encode-process 'utf-8 'utf-8)
 101       (process-kill-without-query punycode-encode-process))
 102     punycode-encode-process))
 103
 104 (defvar punycode-decode-process nil
 105   "Internal variable holding process for punycode encoding.")
 106 (defvar punycode-decode-response nil
 107   "Internal variable holding response data received from punycode process.")
 108
 109 (defun punycode-decode-response-clear ()
 110   (setq punycode-decode-response nil))
 111
 112 (defun punycode-decode-response ()
 113   (while (and (eq (process-status punycode-decode-process) 'run)
 114               (null punycode-decode-response))
 115     (accept-process-output punycode-decode-process 1))
 116   punycode-decode-response)
 117
 118 (defun punycode-decode-filter (process string)
 119   (setq punycode-decode-response (concat punycode-decode-response string)))
 120
 121 (defun punycode-decode-process ()
 122   (if (and punycode-decode-process
 123            (eq (process-status punycode-decode-process) 'run))
 124       punycode-decode-process
 125     (if punycode-decode-process
 126         (condition-case ()
 127             (kill-process punycode-decode-process)
 128           (error)))
 129     (when (setq punycode-decode-process
 130                 (start-process "punycode" nil
 131                                shell-file-name shell-command-switch
 132                                (concat punycode-program " "
 133                                        punycode-decode-parameters)))
 134       (set-process-filter punycode-decode-process 'punycode-decode-filter)
 135       (set-process-coding-system punycode-decode-process 'utf-8 'utf-8)
 136       (process-kill-without-query punycode-decode-process))
 137     punycode-decode-process))
 138
 139 ;; Punycode Elisp API:
 140
 141 (defun punycode-encode (str)
 142   "Returns a Punycode encoding of STR."
 143   (let ((proc (punycode-encode-process))
 144         string)
 145     (if (null proc)
 146         (error "Cannot start idn application")
 147       (punycode-encode-response-clear)
 148       (process-send-string proc (concat str "\n"))
 149       (setq string (punycode-encode-response))
 150       (if (string= (substring string (1- (length string))) "\n")
 151           (substring string 0 (1- (length string)))
 152         string))))
 153
 154 (defun punycode-decode (str)
 155   "Returns a possibly multibyte string which is the punycode decoding of STR."
 156   (let ((proc (punycode-decode-process))
 157         string)
 158     (if (null proc)
 159         (error "Cannot start idn application")
 160       (punycode-decode-response-clear)
 161       (process-send-string proc (concat str "\n"))
 162       (setq string (punycode-decode-response))
 163       (if (string= (substring string (1- (length string))) "\n")
 164           (substring string 0 (1- (length string)))
 165         string))))
 166
 167 (provide 'punycode)
 168
 169 ;;; punycode.el ends here