avfilter/avfilter: Add numbers of (in|out)pads directly to AVFilter

Up until now, an AVFilter's lists of input and output AVFilterPads
were terminated by a sentinel and the only way to get the length
of these lists was by using avfilter_pad_count(). This has two
drawbacks: first, sizeof(AVFilterPad) is not negligible
(i.e. 64B on 64bit systems); second, getting the size involves
a function call instead of just reading the data.

This commit therefore changes this. The sentinels are removed and new
private fields nb_inputs and nb_outputs are added to AVFilter that
contain the number of elements of the respective AVFilterPad array.

Given that AVFilter.(in|out)puts are the only arrays of zero-terminated
AVFilterPads an API user has access to (AVFilterContext.(in|out)put_pads
are not zero-terminated and they already have a size field) the argument
to avfilter_pad_count() is always one of these lists, so it just has to
find the filter the list belongs to and read said number. This is slower
than before, but a replacement function that just reads the internal numbers
that users are expected to switch to will be added soon; and furthermore,
avfilter_pad_count() is probably never called in hot loops anyway.

This saves about 49KiB from the binary; notice that these sentinels are
not in .bss despite being zeroed: they are in .data.rel.ro due to the
non-sentinels.

Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt
2021-08-12 13:05:31 +02:00
parent d53d48c799
commit 8be701d9f7
389 changed files with 906 additions and 1696 deletions

View File

@ -133,7 +133,6 @@ static const AVFilterPad avfilter_vf_vflip_inputs[] = {
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad avfilter_vf_vflip_outputs[] = {
@ -141,7 +140,6 @@ static const AVFilterPad avfilter_vf_vflip_outputs[] = {
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
const AVFilter ff_vf_vflip = {
@ -149,7 +147,7 @@ const AVFilter ff_vf_vflip = {
.description = NULL_IF_CONFIG_SMALL("Flip the input video vertically."),
.priv_size = sizeof(FlipContext),
.priv_class = &vflip_class,
.inputs = avfilter_vf_vflip_inputs,
.outputs = avfilter_vf_vflip_outputs,
FILTER_INPUTS(avfilter_vf_vflip_inputs),
FILTER_OUTPUTS(avfilter_vf_vflip_outputs),
.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
};