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Add a note about the generic-protocol-analyse utilty.

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ehofman 2009-06-30 07:49:29 +00:00 committed by Tim Moore
parent f5ab3756a1
commit 0d609b8033
1 changed files with 29 additions and 6 deletions
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docs-mini/README.protocol
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@ -56,12 +56,14 @@ and data sets, as well as a list of <chunk>s. Each <chunk> defines
a property that should be written (and how), or a variable and which
property it should be written to.
--- ASCII protocol parameters ---
output only:
<binary_mode> BOOL default: false (= ASCII mode)
<preamble> STRING default: "" file header put on top of the file
<postamble> STRING default: "" file footer put at the end of the file
input & output:
<binary_mode> BOOL default: false (= ASCII mode)
<var_separator> STRING default: "" field separator
<line_separator> STRING default: "" separator between data sets
@ -90,6 +92,7 @@ or
<line_separator>\r\n</line_separator>
--- Binary protocol parameters ---
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
@ -115,23 +118,22 @@ each of which describes the properties of on variable to write/read.
<node> the property tree node which provides the data
<type> the value type (needed for formatting)
one of string, float, bool, int (default: int)
<format> defines the actual piece of text which should be sent.
<format> (ASCII protocol only, not used or needed in binary mode)
defines the actual piece of text which should be sent.
it can include "printf" style formatting options like:
<type>
%s string
%d integer (default)
%f float
(not used or needed in binary mode)
<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 to radians).
(for example, degrees Celcius to degrees Fahrenheit).
Chunks can also consist of a single constant <format>, like in:
<format>Data Section</format>
== examples ===================================================================
@ -225,3 +227,24 @@ used as $ fgfs --generic=file,out,1,/tmp/data.xml,xmltest
</PropertyList>
-- Analyzing the resulting binary packet format -------------------------------
A utility called generic-protocol-analyse can be found under
FlightGear/utils/xmlgrep which can be used to analyze the resulting
data packet for the binary protocol.
The output would be something like:
bintest.xml
Generic binary output protocol packet description:
pos | size | type | factor | description
-----|------|--------|------------|------------------------
0 | 4 | int | | indicated speed (kt)
4 | 4 | float | | pitch att (deg)
8 | 4 | float | | magnetic heading (deg)
12 | 4 | int | | outside air temperarure (degF)
16 | 1 | bool | | autocoord
total package size: 17 bytes