Some of the blend mode functions only depend on the underlying type
and therefore need only one version for 9, 10, 12, 14, 16 bits.
This saved 35104B with GCC and 26880B with Clang.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The blend functions currently convert strides from bytes to elements
of the type by using the stride /= sizeof(pixel) idiom. Yet this has
several drawbacks:
1. It invokes undefined behavior that happens to work when stride is
negative: size_t is typically the unsigned type of ptrdiff_t and
therefore the division will be performed as size_t, i.e. use logical
right shifts, making stride very big when sizeof(pixel) is > 1. This
works, because pointer to pixel for accesses entails an implicit
factor of sizeof(pixel) so that everything is correct modulo SIZE_MAX.
Yet this is UB and UBSan complains about it.
2. It makes the compiler emit actual shifts/ands to discard the low bits
shifted away.
3. There may be systems where alignof(uint16_t) or alignof(float) is
strictly smaller than their sizeof, so that the stride (in bytes) is
not guaranteed to be multiple of these sizeofs. In this case, dividing
by sizeof(pixel) is simply wrong.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
These casts cast const away temporarily; they are safe, because
the pointers that are initialized point to const data. But this
is nevertheless not nice and leads to warnings when using
-Wcast-qual. blend_modes.c generates 546 (2*39*7) such warnings
which is the majority of such warnings for FFmpeg as a whole.
vf_blend.c and vf_blend_init.h also use this pattern;
they have also been changed.
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
A filter needs formats.h iff it uses FILTER_QUERY_FUNC();
since lots of filters have been switched to use something
else than FILTER_QUERY_FUNC, they don't need it any more,
but removing this header has been forgotten.
This commit does this; files with formats.h inclusion went down
from 304 to 139 here (it were 449 before the preceding commit).
While just at it, also improve the other headers a bit.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
