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Add support for a binary output mode.

This commit is contained in:
ehofman 2006-04-29 11:14:36 +00:00
parent c9035a46d8
commit 1d75ec0639
2 changed files with 65 additions and 2 deletions

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@ -1,5 +1,5 @@
The generic communication protocol for FlightGear provides a powerfull way
of adding a simple ASCII based output only protocol, just by defining an
of adding a simple ASCII based or binary protocol, just by defining an
XML encoded configuration file.
The definition of the protocol consists of variable separators, line separators,
@ -16,8 +16,9 @@ Each chunck defines:
%s string
%i integer (default)
%f float
(not used or needed in binary mode)
<factor> an optionale multiplication factor which can be used for
<factor> an optional multiplication factor which can be used for
unit conversion. (for example, radians to degrees).
<offset> an optional offset which can be used for unit conversion.
(for example, degrees Celsius to degrees Fahrenheit).
@ -44,6 +45,16 @@ any other charachters just need to be added to "Network/generic.cxx"
The var_separator is placed between each variable, while the line_separator is
placed at the end of each lot of variables.
To enable binary mode, simply include a <binary_mode>true</binary_mode> tag in
your XML file. The format of the binary output is tightly packed, with 1 byte
for bool, 4 bytes for int, and 8 bytes for double. At this time, strings are not
supported. A configurable footer at the end of each "line" or packet of binary
output can be added using the <binary_footer> tag. Options include the length
of the packet, a magic number to simplify decoding. Examples:
<binary_footer>magic,0x12345678</binary_footer>
<binary_footer>length</binary_footer>
<binary_footer>none</binary_footer> <!-- default -->
A simple protocol configuration file then could look something like the
following:
@ -57,6 +68,7 @@ following:
<output>
<line_separator>newline</line_separator>
<var_separator>newline</var_separator>
<binary_mode>false</binary_mode>
<chunk>
<name>speed</name>

51
Protocol/bintest.xml Normal file
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@ -0,0 +1,51 @@
<?xml version="1.0"?>
<PropertyList>
<generic>
<output>
<binary_mode>true</binary_mode>
<binary_footer>magic,0x12345678</binary_footer>
<chunk>
<name>indicated speed (kt)</name>
<type>int</type>
<node>/velocities/airspeed-kt</node>
</chunk>
<chunk>
<name>pitch att (deg)</name>
<type>float</type>
<node>/orientation/pitch-deg</node>
</chunk>
<chunk>
<name>magnetic heading (deg)</name>
<type>float</type>
<node>/orientation/heading-deg</node>
</chunk>
<chunk>
<name>outside air temperarure (degF)</name>
<type>int</type>
<node>/environment/temperature-degf</node>
</chunk>
<chunk>
<name>autocoord</name>
<type>boolean</type>
<node>/sim/auto-coordination</node>
</chunk>
<chunk>
<name>clock</name>
<type>string</type>
<node>/instrumentation/clock/indicated-string</node>
</chunk>
</output>
</generic>
</PropertyList>