When the flags contain a value that only has the most-significant bit
set then ffsl will return the size of an unsigned long. According to
the C spec it is undefined what happens when shifting by a number
greater than or equal to the size of the left operand. On Intel (and
probably others) this seems to end up being a no-op so the iteration
breaks. To fix this we can split the shift into two separate
shifts. We always need to shift by at least one bit so we can put this
one bit shift into a separate operator.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
This adds some macros to iterate over all the bits set in an array of
flags. The macros are a bit awkward because it tries to avoid using a
callback pointer so that the code is inlined.
cogl_bitmask is now using these macros as well so that the logic can
be shared.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Previously cogl-flags was using an array of ints to store the
flags. There was a comment saying that it would be nice to use longs
but this is awkward because g_parse_debug_flags can only work in
ints. This is a silly reason not to use longs because we can just
parse multiple sets of flags per long. This patch therefore changes
cogl-flags to use longs and tweaks the debug key parsing code.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
Previously the mask of available winsys features was stored in a
CoglBitmask. That isn't the ideal type to use for this because it is
intended for a growable array of bits so it can allocate extra memory
if there are more than 31 flags set. For the winsys feature flags the
highest used bit is known at compile time so it makes sense to
allocate a fixed array instead. This is conceptually similar to the
CoglDebugFlags which are stored in an array of integers with macros to
test a bit in the array. This moves the macros used for CoglDebugFlags
to cogl-flags.h and makes them more generic so they can be shared with
CoglContext.
