[FFmpeg-devel] [PATCH] avcodec/bsf: Avoid allocation for AVBSFInternal

[Nicolas George]

James Almer (12020-08-10):
> It adds an extra struct and makes the code harder to read. Might as well
> just do
> 
> ctx = av_mallocz(sizeof(*ctx) + sizeof(AVBSFInternal));
> ctx->internal = &ctx[1];

This is exactly what the code does, except without the undefined
behaviors, because what you just wrote is completely invalid.

> And i *really* want to emphasize just how cold this function is,
> especially ever since av_bsf_flush() was introduced, and even more so if
> av_bsf_close() is also committed.

You missed the part where Andreas said this was a proof of concept, and
the same should be done for all similar cases. IIRC, you like
consistency.

> Skipping a 12 byte allocation does nothing on any system with a C
> library worth its salt, where it will be cached and ready to be returned
> by malloc.

It does save some memory.

> Can we not get overtly clever with code obfuscation?

There is no obfuscation, just a very standard an common practice.

Regards,

-- 
  Nicolas George
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