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.
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| @@ -540,14 +540,20 @@ int avfilter_process_command(AVFilterContext *filter, const char *cmd, const cha · 539 unmodified lines | ||
| 540 | 540 | |
| 541 | 541 | int avfilter_pad_count(const AVFilterPad *pads) |
| 542 | 542 | { |
| 543 | − int count; | |
| 543 | + const AVFilter *filter; | |
| 544 | + void *opaque = NULL; | |
| 544 | 545 | |
| 545 | 546 | if (!pads) |
| 546 | 547 | return 0; |
| 547 | 548 | |
| 548 | − for (count = 0; pads->name; count++) | |
| 549 | − pads++; | |
| 550 | − return count; | |
| 549 | + while (filter = av_filter_iterate(&opaque)) { | |
| 550 | + if (pads == filter->inputs) | |
| 551 | + return filter->nb_inputs; | |
| 552 | + if (pads == filter->outputs) | |
| 553 | + return filter->nb_outputs; | |
| 554 | + } | |
| 555 | + | |
| 556 | + av_assert0(!"AVFilterPad list not from a filter"); | |
| 551 | 557 | } |
| 552 | 558 | |
| 553 | 559 | static const char *default_filter_name(void *filter_ctx) |
| @@ -650,7 +656,7 @@ AVFilterContext *ff_filter_alloc(const AVFilter *filter, const char *inst_name) · 96 unmodified lines | ||
| 650 | 656 | goto err; |
| 651 | 657 | ret->internal->execute = default_execute; |
| 652 | 658 | |
| 653 | − ret->nb_inputs = avfilter_pad_count(filter->inputs); | |
| 659 | + ret->nb_inputs = filter->nb_inputs; | |
| 654 | 660 | if (ret->nb_inputs ) { |
| 655 | 661 | ret->input_pads = av_memdup(filter->inputs, ret->nb_inputs * sizeof(*filter->inputs)); |
| 656 | 662 | if (!ret->input_pads) |
| @@ -660,7 +666,7 @@ AVFilterContext *ff_filter_alloc(const AVFilter *filter, const char *inst_name) · 3 unmodified lines | ||
| 660 | 666 | goto err; |
| 661 | 667 | } |
| 662 | 668 | |
| 663 | − ret->nb_outputs = avfilter_pad_count(filter->outputs); | |
| 669 | + ret->nb_outputs = filter->nb_outputs; | |
| 664 | 670 | if (ret->nb_outputs) { |
| 665 | 671 | ret->output_pads = av_memdup(filter->outputs, ret->nb_outputs * sizeof(*filter->outputs)); |
| 666 | 672 | if (!ret->output_pads) |