From f4a7434f16afc4616a34a7cd1bd8e592ed04e89f Mon Sep 17 00:00:00 2001 From: Måns Rullgård Date: Thu, 18 Feb 2010 13:44:38 +0000 Subject: Add alias-safe aligned AV_[RW]N macros Originally committed as revision 21880 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavutil/intreadwrite.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'libavutil') diff --git a/libavutil/intreadwrite.h b/libavutil/intreadwrite.h index 7565ef711e..b1e4e9a9a1 100644 --- a/libavutil/intreadwrite.h +++ b/libavutil/intreadwrite.h @@ -422,6 +422,38 @@ 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 av_alias##s*)(p))->u##s) +#define AV_WNA(s, p, v) (((av_alias##s*)(p))->u##s = (v)) + +#ifndef AV_RN16A +# define AV_RN16A(p) AV_RNA(16, p) +#endif + +#ifndef AV_RN32A +# define AV_RN32A(p) AV_RNA(32, p) +#endif + +#ifndef AV_RN64A +# define AV_RN64A(p) AV_RNA(64, p) +#endif + +#ifndef AV_WN16A +# define AV_WN16A(p, v) AV_WNA(16, p, v) +#endif + +#ifndef AV_WN32A +# define AV_WN32A(p, v) AV_WNA(32, p, v) +#endif + +#ifndef AV_WN64A +# define AV_WN64A(p, v) AV_WNA(64, p, v) +#endif + /* Parameters for AV_COPY*, AV_SWAP*, AV_ZERO* must be * naturally aligned. They may be implemented using MMX, * so emms_c() must be called before using any float code -- cgit v1.2.3