Quoting Andreas Rheinhardt (2021-04-08 12:27:03)
> Anton Khirnov:
> > Quoting Andreas Rheinhardt (2021-04-08 11:41:41)
> >> Anton Khirnov:
> >>> ---
> >>> libavutil/video_enc_params.c | 6 +++---
> >>> 1 file changed, 3 insertions(+), 3 deletions(-)
> >>>
> >>> diff --git a/libavutil/video_enc_params.c b/libavutil/video_enc_params.c
> >>> index 635176ab91..1779a8799a 100644
> >>> --- a/libavutil/video_enc_params.c
> >>> +++ b/libavutil/video_enc_params.c
> >>> @@ -30,9 +30,9 @@ AVVideoEncParams *av_video_enc_params_alloc(enum
> >>> AVVideoEncParamsType type,
> >>> unsigned int nb_blocks,
> >>> size_t *out_size)
> >>> {
> >>> AVVideoEncParams *par;
> >>> - size_t size;
> >>> + size_t blocks_offset = FFALIGN(sizeof(*par), 8);
> >>> + size_t size = blocks_offset;
> >>>
> >>> - size = sizeof(*par);
> >>> if (nb_blocks > (SIZE_MAX - size) / sizeof(AVVideoBlockParams))
> >>> return NULL;
> >>> size += sizeof(AVVideoBlockParams) * nb_blocks;
> >>> @@ -44,7 +44,7 @@ AVVideoEncParams *av_video_enc_params_alloc(enum
> >>> AVVideoEncParamsType type,
> >>> par->type = type;
> >>> par->nb_blocks = nb_blocks;
> >>> par->block_size = sizeof(AVVideoBlockParams);
> >>> - par->blocks_offset = sizeof(*par);
> >>> + par->blocks_offset = blocks_offset;
> >>>
> >>> if (out_size)
> >>> *out_size = size;
> >>>
> >> Wouldn't it be safer to just define a struct { AVVideoEncParams header;
> >> AVVideoBlockParams blocks[1]; } and use the offset of blocks in that?
> >
> > I don't see how it would be safer and it prevents you from adding new
> > fields to AVVideoEncParams
> >
> Safer: You are making assumptions about the alignment of
> AVVideoBlockParams; these assumptions may or may not be fulfilled in
> practice.
> And I really don't get your point about this preventing the addition of
> new fields to AVVideoEncParams. If something is added to
> AVVideoEncParams, sizeof(header) and offsetof(blocks) will grow
> automatically as required.
Nevermind, I misunderstood your suggestion. I suppose it works better
indeed.
--
Anton Khirnov
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