Use unions to perform safe type-punning.

Signed-off-by: Drew Fisher <[email protected]>
rassaifred · Feb 5, 2012 · 5795655 · 5795655
1 parent 713c715
commit 5795655
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Showing 2 changed files with 33 additions and 15 deletions.
diff --git a/src/cameras.c b/src/cameras.c
@@ -910,15 +910,25 @@ static int freenect_fetch_zero_plane_info(freenect_device *dev)
 	}
 
 	memcpy(&(dev->registration.zero_plane_info), reply + 94, sizeof(dev->registration.zero_plane_info));
-	uint32_t temp;
-	temp = fn_le32(*((uint32_t*)(&dev->registration.zero_plane_info.dcmos_emitter_dist)));
-	dev->registration.zero_plane_info.dcmos_emitter_dist   = *((float*)(&temp));
-	temp = fn_le32(*((uint32_t*)(&dev->registration.zero_plane_info.dcmos_rcmos_dist)));
-	dev->registration.zero_plane_info.dcmos_rcmos_dist     = *((float*)(&temp));
-	temp = fn_le32(*((uint32_t*)(&dev->registration.zero_plane_info.reference_distance)));
-	dev->registration.zero_plane_info.reference_distance   = *((float*)(&temp));
-	temp = fn_le32(*((uint32_t*)(&dev->registration.zero_plane_info.reference_pixel_size)));
-	dev->registration.zero_plane_info.reference_pixel_size = *((float*)(&temp));
+	union {
+		uint32_t ui;
+		float f;
+	} conversion_union;
+	conversion_union.f = dev->registration.zero_plane_info.dcmos_emitter_dist;
+	conversion_union.ui = fn_le32(conversion_union.ui);
+	dev->registration.zero_plane_info.dcmos_emitter_dist = conversion_union.f;
+
+	conversion_union.f = dev->registration.zero_plane_info.dcmos_rcmos_dist;
+	conversion_union.ui = fn_le32(conversion_union.ui);
+	dev->registration.zero_plane_info.dcmos_rcmos_dist = conversion_union.f;
+
+	conversion_union.f = dev->registration.zero_plane_info.reference_distance;
+	conversion_union.ui = fn_le32(conversion_union.ui);
+	dev->registration.zero_plane_info.reference_distance = conversion_union.f;
+
+	conversion_union.f = dev->registration.zero_plane_info.reference_pixel_size;
+	conversion_union.ui = fn_le32(conversion_union.ui);
+	dev->registration.zero_plane_info.reference_pixel_size = conversion_union.f;
 
 	// WTF is all this data?  it's way bigger than sizeof(XnFixedParams)...
 	FN_SPEW("dcmos_emitter_distance: %f\n", dev->registration.zero_plane_info.dcmos_emitter_dist);

diff --git a/src/freenect_internal.h b/src/freenect_internal.h
@@ -96,16 +96,24 @@ static inline uint32_t fn_le32(uint32_t d)
 static inline int16_t fn_le16s(int16_t s)
 {
 	// reinterpret cast to unsigned, use the normal fn_le16, and then reinterpret cast back
-	uint16_t temp = (*(uint16_t*)(&s));
-	temp = fn_le16(temp);
-	return *((int16_t*)(&temp));
+	union {
+		int16_t s;
+		uint16_t u;
+	} conversion_union;
+	conversion_union.s = s;
+	conversion_union.u = fn_le16(conversion_union.u);
+	return conversion_union.s;
 }
 static inline int32_t fn_le32s(int32_t s)
 {
 	// reinterpret cast to unsigned, use the normal fn_le32, and then reinterpret cast back
-	uint32_t temp = (*(uint32_t*)(&s));
-	temp = fn_le32(temp);
-	return *((int32_t*)(&temp));
+	union {
+		int32_t s;
+		uint32_t u;
+	} conversion_union;
+	conversion_union.s = s;
+	conversion_union.u = fn_le32(conversion_union.u);
+	return conversion_union.s;
 }
 #else
 #define fn_le16(x) (x)