jeeps bug?

[tsteven4]

Jeeps was introduced in bb94c57 in 2002. At that time gpssend.c had a function GPS_Make_Packet, which included parameters UC data and int16 n. Presumably n is the number of unsigned characters in data.

Why is n being compared to DLE (#define DLE 0x10), which one would assume is the Data Link Escape ASCII character?

gpsbabel/gpsbabel/jeeps/gpssend.c

Lines 62 to 66 in bb94c57

	if(n == DLE)
	{
	++(*packet)->bytes;
	*q++ = DLE;
	}

Today this has led to a similar comparison:

gpsbabel/jeeps/gpssend.cc

Lines 61 to 64 in 66fa37e

	if (in.n == DLE) {
	++bytes;
	*q++ = DLE;
	}

[tsteven4]

This sounds like "DLE stuffing" as described in the Garmin Device Interface Specification.

[robertlipe]

Right. That spec didn't exist (outside Olathe) at the time. I remember there was some weirdness in the USB implementation. It's not necessary at the bus level, but I can't remember if they faithfully mimicked this in USB or not. So there may be some related goofy - looking code in the USB side, too.

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