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

[Måns Rullgård]

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.

-- 
M?ns Rullg?rd
mans at mansr.com