memory optimization, using posix_memalign (#350)

src/Cafe/OS/libs/h264_avc/H264Dec.cpp

@@ -194,8 +194,22 @@ namespace H264
 #ifdef _WIN32
 			return _aligned_malloc(size, alignment);
 #else
-			size += ((size % alignment) == 0) ? 0 : alignment - (size % alignment);
+			// alignment is atleast sizeof(void*)
-			return aligned_alloc(alignment, size);
+			alignment = std::max<WORD32>(alignment, sizeof(void*));
+
+			//smallest multiple of 2 at least as large as alignment
+			alignment--;
+			alignment |= alignment << 1;
+			alignment |= alignment >> 1;
+			alignment |= alignment >> 2;
+			alignment |= alignment >> 4;
+			alignment |= alignment >> 8;
+			alignment |= alignment >> 16;
+			alignment ^= (alignment >> 1);
+
+			void* temp;
+			posix_memalign(&temp, (size_t)alignment, (size_t)size);
+			return temp;
 #endif
 		}