[FFmpeg-cvslog] r21880 - trunk/libavutil/intreadwrite.h

[mru]

Author: mru
Date: Thu Feb 18 14:44:38 2010
New Revision: 21880

Log:
Add alias-safe aligned AV_[RW]N macros

Modified:
   trunk/libavutil/intreadwrite.h

Modified: trunk/libavutil/intreadwrite.h
==============================================================================
--- trunk/libavutil/intreadwrite.h	Thu Feb 18 14:40:24 2010	(r21879)
+++ trunk/libavutil/intreadwrite.h	Thu Feb 18 14:44:38 2010	(r21880)
@@ -422,6 +422,38 @@ union unaligned_16 { uint16_t l; } __att
     } 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