2 Bit::MorseSignals - The MorseSignals protocol.
8 In unidirectionnal communication channels (such as networking or IPC),
9 the main issue is often to know the length of the message. Some possible
10 solutions are fixed-length messages (which is quite cumbersome) or a
11 special ending sequence (but it no longer can appear in the data). This
12 module proposes another solution, by using a begin/end signature
13 specialized for each message.
15 An actual implementation is also provided :
17 Bit::MorseSignals::Emitter is a base class for emitters ;
18 Bit::MorseSignals::Receiver is a base class for receivers ;
20 Go to those pages if you just want the stuff done and don't care about
24 Each byte of the data string is converted into its bits sequence, with
25 bits of lowest weight coming first. All those bits sequences are put
26 into the same order as the characters occur in the string.
28 The header is composed of three bits (lowest weight coming first) :
30 - The 2 first ones denotes the data type : a value of 0 is used for a
31 plain string, 1 for an UTF-8 encoded string, and 2 for a Storable
32 object. See also the "CONSTANTS" sections ;
33 - The third one is reserved. For compatibility reasons, the receiver
34 should for now enforce the message data type to plain when this bit is
37 The emitter computes then the longuest sequence of successives 0 (say,
38 m) and 1 (n) in the concatenation of the header and the data. A
39 signature is then chosen :
41 - If m > n, we take n+1 times 1 followed by one 0 ;
42 - Otherwise, we take m+1 times 0 followed by one 1.
44 The signal is then formed by concatenating the signature, the header,
45 the data bits and the reversed signature (i.e. the bits of the signature
46 in the reverse order).
48 a ... a b | t0 t1 r | ... data ... | b a ... a
49 signature | header | data | reversed signature
51 The receiver knows that the signature has been sent when it has catched
52 at least one 0 and one 1. The signal is completely transferred when it
53 has received for the first time the whole reversed signature.
57 Default for non-references messages. Try to guess if the given scalar is
58 an UTF-8 string with "Encode::is_utf8".
61 Treats the data as a plain string. No extra mangling in done.
64 Treats the data as an UTF-8 string. The string is
65 "Encode::encode_utf8"'d in a binary string before sending, and
66 "Encode::decode_utf8"'d by the receiver.
69 The scalar, array or hash reference given is "Storable::freeze"'d by the
70 sender and "Storable::thaw"'d by the receiver.
73 The constants "BM_DATA_AUTO", "BM_DATA_PLAIN", "BM_DATA_UTF8" and
74 "BM_DATA_STORABLE" are only exported on request, either by specifying
75 their names or the ':consts' tag.
78 Carp (standard since perl 5), Encode (since perl 5.007003), Storable
82 Bit::MorseSignals::Emitter, Bit::MorseSignals::Receiver.
85 Vincent Pit, "<perl at profvince.com>"
87 You can contact me by mail or on #perl @ FreeNode (vincent or
91 Please report any bugs or feature requests to "bug-bit-morsesignals at
92 rt.cpan.org", or through the web interface at
93 <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Bit-MorseSignals>. I
94 will be notified, and then you'll automatically be notified of progress
95 on your bug as I make changes.
98 You can find documentation for this module with the perldoc command.
100 perldoc Bit::MorseSignals
103 Copyright 2008 Vincent Pit, all rights reserved.
105 This program is free software; you can redistribute it and/or modify it
106 under the same terms as Perl itself.