From 8ba3d978dbb4c3dfc8657ef5c6944f04c8064d51 Mon Sep 17 00:00:00 2001
From: kgv <kgv@opencascade.com>
Date: Fri, 11 Oct 2019 14:56:03 +0300
Subject: [PATCH] 0031048: Visualization - runtime error reported by Clang
 undefined behavior sanitizer in Image_AlienPixMap::Save()

Image_PixMapData - use unsigned math (uintptr_t) instead of signed math with pointers for defining negative stride.
---
 src/Image/Image_PixMapData.hxx | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Image/Image_PixMapData.hxx b/src/Image/Image_PixMapData.hxx
index ec870b1dd9..046bc1bc76 100644
--- a/src/Image/Image_PixMapData.hxx
+++ b/src/Image/Image_PixMapData.hxx
@@ -74,27 +74,27 @@ public:
   //! @return data pointer to requested row (first column).
   inline const Standard_Byte* Row (const Standard_Size theRow) const
   {
-    return myTopRowPtr + SizeRowBytes * theRow * TopToDown;
+    return myTopRowPtr + ptrdiff_t(SizeRowBytes * theRow * TopToDown);
   }
 
   //! @return data pointer to requested row (first column).
   inline Standard_Byte* ChangeRow (const Standard_Size theRow)
   {
-    return myTopRowPtr + SizeRowBytes * theRow * TopToDown;
+    return myTopRowPtr + ptrdiff_t(SizeRowBytes * theRow * TopToDown);
   }
 
   //! @return data pointer to requested position.
   inline const Standard_Byte* Value (const Standard_Size theRow,
                                      const Standard_Size theCol) const
   {
-    return myTopRowPtr + SizeRowBytes * theRow * TopToDown + SizeBPP * theCol;
+    return myTopRowPtr + ptrdiff_t(SizeRowBytes * theRow * TopToDown) + SizeBPP * theCol;
   }
 
   //! @return data pointer to requested position.
   inline Standard_Byte* ChangeValue (const Standard_Size theRow,
                                      const Standard_Size theCol)
   {
-    return myTopRowPtr + SizeRowBytes * theRow * TopToDown + SizeBPP * theCol;
+    return myTopRowPtr + ptrdiff_t(SizeRowBytes * theRow * TopToDown) + SizeBPP * theCol;
   }
 
   //! Compute the maximal row alignment for current row size.