Fix the alignment computation inside switches which start at
an unaligned pos.
This affects both explicit and implicit align pads.
The alignment offset is derived from the lowest 3 bits of
the pointer to the protocol-data at the start of the switch.
This is sufficient for correcting all alignments up to 8-byte alignment.
As far as I know there is no bigger alignment than 8-byte for the
X-protocol.
Example:
struct InputState, where the switch starts after two 1-byte fields,
which is a 2 byte offset for 4-byte and 8-byte alignment.
The previous problem can be demonstrated when adding a
<pad align="4"/> at the end of case "key".
(Or when finding a testcase which reports the case "valuator" not
at the last position of the QueryDeviceState-reply.
I didn't find such a testcase, so I have used the pad align
as described above.)
V2: patch modified in order to fix bugs which I found when working on the
next issue:
* xcb_padding_offset has to be set 0 when xcb_block_len is set 0
* xcb_padding_offset cannot be "const" therefore
* for unpack and unserialize, the padding_offset must computed
from _buffer instead of from the aux_var.
V3: patch revised according to suggestion by Ran Benita:
* only create and use xcb_padding_offset for switch
Message-ID: <
1410298000-24734-1-git-send-email-chris@demorecorder.com>
Patch-Thread-Subject: [Xcb] xinput:QueryDeviceState: full-support: generator and xml-changes
Patch-Set: QueryDeviceState
Patch-Number: libxcb 4/4
Patch-Version: V3
Signed-off-by: Christian Linhart <chris@DemoRecorder.com>
Reviewed-By: Ran Benita <ran234@gmail.com>