Fix kaitai python version for messages ending in a variable-length string #1468
+52
−12
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Description
The kaitai python bindings contain an internal helper class called
BufferKaitaiStream
, which is intended to be a faster work-alike for theKaitaiStream
class provided by the kaitai python runtime. This is implemented using an inner class calledKaitaiStream.IOBytes
, which emulates theio.BytesIO
interface expected byKaitaiStream
. Unfortunately the previous implementation ofBufferKaitaiStruct.BytesIO.read()
contained a bug which meant that it did not correctly handle messages (such asMSG_DGNSS_STATUS
andMSG_PROFILING_THREAD_INFO
) which end in a variable-length string. In this case,KaitaiStream.read_bytes_full()
would callBufferKaitaiStruct.BytesIO.read()
without any arguments, with the expectation that it would return all of the data until the end of the message.The majority of this PR is concerned with creating a test case for using the kaitai python bindings which completely avoids the use of
io.BytesIO
abstraction. According to the benchmark this approach is approximately 15% faster than both of the other hybrid variants.@swift-nav/algint-team
API compatibility
Does this change introduce a API compatibility risk?
No, it is only a bug fix.
API compatibility plan
If the above is "Yes", please detail the compatibility (or migration) plan: