Hi, I am working on the USB HID dissector and I need to dissect data on a bit by bit basis, instead of byte. The data structure is completely dynamic (described by the HID descriptor) and the basic data block is the bit. Any bit or sequence of bits can have a meaning, the data can be completely unaligned. See the following example which shows different fields distributed in a 2 byte packet.
0110000000011111 ^^^\__^___/\_^_/ ||| | | ||| | | Y axis (5 bit wide) ||| | ||| | X axis (8 bit wide) ||| ||| button 3 || || button 2 | | button 1 What is the best way to dissect this data? I feel like I am going to have to basically write a complicated internal wrapper around the tvb API, and that won't even work properly in some cases. Is modifying the tvb API to allow data control on a bit level reasonable? I am not very aware of the internals, but as far as I can tell that would not be trivial. Even if it is a bit complicated, is it something that could be considered? Is USB HID the only protocol running into this issue? I guess most stuff is aligned, but I if I had to guess I'd a few other protocol would possibly need this finer control. I feel like I am opening a can of worms here, sorry about that :P Cheers, Filipe Laíns
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