[FFmpeg-devel] [PATCH 7/7] Add alias-safe aligned AV_[RW]N macros

[Reimar Döffinger]

On Fri, Feb 05, 2010 at 10:51:59AM +0100, Michael Niedermayer wrote:
> On Sun, Jan 31, 2010 at 02:08:29AM +0000, M?ns Rullg?rd wrote:
> > Michael Niedermayer <michaelni at gmx.at> writes:
> > 
> > > On Fri, Jan 29, 2010 at 02:12:14AM +0000, Mans Rullgard wrote:
> > >> ---
> > >>  libavutil/intreadwrite.h |   32 ++++++++++++++++++++++++++++++++
> > >>  1 files changed, 32 insertions(+), 0 deletions(-)
> > >> 
> > >> diff --git a/libavutil/intreadwrite.h b/libavutil/intreadwrite.h
> > >> index 631db75..61ad488 100644
> > >> --- a/libavutil/intreadwrite.h
> > >> +++ b/libavutil/intreadwrite.h
> > >> @@ -418,6 +418,38 @@ union unaligned_16 { uint16_t l; } __attribute__((packed)) av_alias;
> > >>      } while(0)
> > >>  #endif
> > >>  
> > >> +/*
> > >> + * The AV_[RW]NA macros access naturally aligned data
> > >> + * in a type-safe way.
> > >> + */
> > >> +
> > >> +#define AV_RNA(s, p)    (((const ff_alias##s*)(p))->u##s)
> > >> +#define AV_WNA(s, p, v) (((ff_alias##s*)(p))->u##s = (v))
> > >
> > > do we really need yet another set?
> > 
> > We need one set for aligned accesses and one for unaligned, yes.
> 
> yes i agree, doesnt mean i like it though

What I don't particularly like is that "NA" is a bit confusing, unless
you extrapolate from the other naming it might just as well mean "not aligned".
No, I don't have better ideas...