From 8be701d9f7f77ff2282cc7fe6e0791ca5419de70 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Thu, 12 Aug 2021 13:05:31 +0200 Subject: 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 Signed-off-by: Andreas Rheinhardt --- libavfilter/avfilter.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'libavfilter/avfilter.c') diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c index ea22b247de..a869a76b71 100644 --- a/libavfilter/avfilter.c +++ b/libavfilter/avfilter.c @@ -540,14 +540,20 @@ int avfilter_process_command(AVFilterContext *filter, const char *cmd, const cha int avfilter_pad_count(const AVFilterPad *pads) { - int count; + const AVFilter *filter; + void *opaque = NULL; if (!pads) return 0; - for (count = 0; pads->name; count++) - pads++; - return count; + while (filter = av_filter_iterate(&opaque)) { + if (pads == filter->inputs) + return filter->nb_inputs; + if (pads == filter->outputs) + return filter->nb_outputs; + } + + av_assert0(!"AVFilterPad list not from a filter"); } static const char *default_filter_name(void *filter_ctx) @@ -650,7 +656,7 @@ AVFilterContext *ff_filter_alloc(const AVFilter *filter, const char *inst_name) goto err; ret->internal->execute = default_execute; - ret->nb_inputs = avfilter_pad_count(filter->inputs); + ret->nb_inputs = filter->nb_inputs; if (ret->nb_inputs ) { ret->input_pads = av_memdup(filter->inputs, ret->nb_inputs * sizeof(*filter->inputs)); if (!ret->input_pads) @@ -660,7 +666,7 @@ AVFilterContext *ff_filter_alloc(const AVFilter *filter, const char *inst_name) goto err; } - ret->nb_outputs = avfilter_pad_count(filter->outputs); + ret->nb_outputs = filter->nb_outputs; if (ret->nb_outputs) { ret->output_pads = av_memdup(filter->outputs, ret->nb_outputs * sizeof(*filter->outputs)); if (!ret->output_pads) -- cgit v1.2.3