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+ − 1 ;;; multicast.el --- lisp frontend for multicast connections in XEmacs
+ − 2
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+ − 3 ;; Copyright (C) 1997-2000 Didier Verna.
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+ − 4 ;; Copyright (C) 2002 Ben Wing.
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+ − 5
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+ − 6 ;; Author: Didier Verna <didier@xemacs.org>
+ − 7 ;; Maintainer: Didier Verna <didier@xemacs.org>
+ − 8 ;; Created: Thu Dec 4 16:37:39 1997
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+ − 9 ;; Last Revision: Mon Jan 19 19:10:50 1998
+ − 10 ;; Current Version: 0.4
+ − 11 ;; Keywords: dumped comm processes
+ − 12
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+ − 13 ;; This file is part of XEmacs.
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+ − 14
+ − 15 ;; XEmacs is free software; you can redistribute it and/or modify
+ − 16 ;; it under the terms of the GNU General Public License as published by
+ − 17 ;; the Free Software Foundation; either version 2 of the License, or
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+ − 18 ;; (at your option) any later version.
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+ − 19
+ − 20 ;; XEmacs is distributed in the hope that it will be useful,
+ − 21 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+ − 22 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ − 23 ;; GNU General Public License for more details.
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+ − 24
+ − 25 ;; You should have received a copy of the GNU General Public License
+ − 26 ;; along with this program; if not, write to the Free Software
+ − 27 ;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ − 28
+ − 29
+ − 30 ;;; Commentary:
+ − 31
+ − 32 ;; This file just contains a lisp frontend to the internal function
+ − 33 ;; open-multicast-group-internal written in C and belonging to process.c
+ − 34 ;; Well, nothing much to say about it ... read the doc string.
+ − 35
+ − 36
+ − 37 ;;; Change Log:
+ − 38
+ − 39 ;; Rev. of Mon Jan 19 19:04:44 1998 : packaging cleanup
+ − 40 ;; Rev. of Thu Dec 11 13:54:26 1997 : updated the docstring
+ − 41 ;; Rev. of Mon Dec 8 15:28:47 1997 : Improved the doc string
+ − 42 ;; Rev. of Thu Dec 4 16:38:09 1997 : Initial Version.
+ − 43
+ − 44
+ − 45 ;;; Code:
+ − 46
+ − 47 (defun open-multicast-group (name buffer address)
+ − 48 "Open a multicast connection on the specified address.
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+ − 49 Returns a process object to represent the connection.
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+ − 50 Input and output work as for subprocesses; `delete-process' closes it.
+ − 51 NAME is a name for the process. It is modified if necessary to make it unique.
+ − 52 BUFFER is the buffer (or buffer-name) to associate with the process.
+ − 53 Process output goes at the end of that buffer, unless you specify an output
+ − 54 stream or filter function to handle the output.
+ − 55 BUFFER may be also nil, meaning that this process is not associated with any
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+ − 56 buffer.
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+ − 57 ADDRESS specifies a standard multicast address \"dest/port/ttl\":
+ − 58 dest is an internet address between 224.0.0.0 and 239.255.255.255
+ − 59 port is a communication port like in traditional unicast
+ − 60 ttl is the time-to-live (15 for site, 63 for region and 127 for world).
+ − 61
+ − 62 WARNING: it is *strongly* recommended to avoid using groups beginning with
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+ − 63 224 or 239. Such groups are considered 'admin' groups, and may
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+ − 64 behave in a surprising way ...
+ − 65
+ − 66 The read/write coding systems used for process I/O on the process are
+ − 67 determined as follows:
+ − 68
+ − 69 1. `coding-system-for-read', `coding-system-for-write', if non-nil.
+ − 70 (Intended as a temporary overriding mechanism for use by Lisp
+ − 71 code.)
+ − 72 2. The matching value for the port from `network-coding-system-alist',
+ − 73 if any, and if non-nil. The value may be either a single coding
+ − 74 system, used for both read and write; or a cons of read/write; or a
+ − 75 function, called to get one of the other two values.
+ − 76 3. The value of `default-network-coding-system', which should be a cons
+ − 77 of read/write coding systems, if the values are non-nil.
+ − 78 4. The coding system `undecided' for read, and `raw-text' for write.
+ − 79
+ − 80 Note that the processes of determining the read and write coding systems
+ − 81 proceed essentially independently one from the other, as in `start-process'.
+ − 82
+ − 83 You can change the coding systems later on using
+ − 84 `set-process-coding-system', `set-process-input-coding-system', or
+ − 85 `set-process-output-coding-system'."
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+ − 86 (let (dest port ttl)
+ − 87 ;; We check only the general form of the multicast address.
+ − 88 ;; The rest will be handled by the internal function.
+ − 89 (string-match "^\\([0-9\\.]+\\)/\\([0-9]+\\)/\\([0-9]+\\)$" address)
+ − 90 (and (not (and (= (match-beginning 0) 0)
+ − 91 (= (match-end 0) (length address))))
+ − 92 (error "malformed multicast address: %s" address))
+ − 93 (and (not (setq dest (match-string 1 address)))
+ − 94 (error "invalid destination specification."))
+ − 95 (and (= 0 (setq port (string-to-int (match-string 2 address))))
+ − 96 (error "invalid port specification."))
+ − 97 (and (= 0 (setq ttl (string-to-int (match-string 3 address))))
+ − 98 (error "invalid ttl specification."))
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+ − 99 (let (cs-r cs-w)
+ − 100 (let (ret)
+ − 101 (catch 'found
+ − 102 (let ((alist network-coding-system-alist)
+ − 103 (case-fold-search nil)
+ − 104 pattern)
+ − 105 (while alist
+ − 106 (setq pattern (car (car alist)))
+ − 107 (and
+ − 108 (cond ((numberp pattern)
+ − 109 (and (numberp port)
+ − 110 (eq pattern port)))
+ − 111 ((stringp pattern)
+ − 112 (or (and (stringp port)
+ − 113 (string-match pattern port))
+ − 114 (and (numberp port)
+ − 115 (string-match pattern
+ − 116 (number-to-string port))))))
+ − 117 (throw 'found (setq ret (cdr (car alist)))))
+ − 118 (setq alist (cdr alist))
+ − 119 )))
+ − 120 (if (functionp ret)
+ − 121 (setq ret (funcall ret 'open-multicast-group port)))
+ − 122 (cond ((consp ret)
+ − 123 (setq cs-r (car ret)
+ − 124 cs-w (cdr ret)))
+ − 125 ((and ret (find-coding-system ret))
+ − 126 (setq cs-r ret
+ − 127 cs-w ret))))
+ − 128 (let ((coding-system-for-read
+ − 129 (or coding-system-for-read cs-r
+ − 130 (car default-network-coding-system)
+ − 131 'undecided))
+ − 132 (coding-system-for-write
+ − 133 (or coding-system-for-write cs-w
+ − 134 (cdr default-network-coding-system)
+ − 135 'raw-text)))
+ − 136 (declare-fboundp (open-multicast-group-internal name buffer dest port
+ − 137 ttl))))))
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+ − 138
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+ − 139 ;;; multicast.el ends here
