1 files changed, 87 insertions, 0 deletions
diff --git a/nx-X11/programs/Xserver/hw/nxagent/GCOps.c b/nx-X11/programs/Xserver/hw/nxagent/GCOps.c
index 83aa04f11..9afd6e392 100644
--- a/nx-X11/programs/Xserver/hw/nxagent/GCOps.c
+++ b/nx-X11/programs/Xserver/hw/nxagent/GCOps.c
@@ -594,6 +594,8 @@ RegionPtr nxagentCopyArea(DrawablePtr pSrcDrawable, DrawablePtr pDstDrawable,
   unsigned int format;
   unsigned long planeMask = 0xffffffff;
 
+  int oldDstxyValue;
+
   RegionPtr pDstRegion;
 
   int skip = 0;
@@ -605,6 +607,91 @@ RegionPtr nxagentCopyArea(DrawablePtr pSrcDrawable, DrawablePtr pDstDrawable,
                           (void *) pDstDrawable, srcx, srcy, dstx, dsty, width, height);
   #endif
 
+ /*
+  * Here, before using fbDoCopy() called by fbCopyArea(),
+  * it should be provided that the cast in fbDoCopy() from
+  * int to short int would not cut off significative bits.
+  */
+
+  if (dstx + pDstDrawable->x + width > 32767)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentCopyArea: x2 exceeding short int.\n");
+    #endif
+
+    width = 32767 - dstx - pDstDrawable->x;
+
+    if (width <= 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentCopyArea: Returning null on x2 check.\n");
+      #endif
+
+      return NullRegion;
+    }
+  }
+
+  if (dstx + pDstDrawable->x < -32768)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentCopyArea: x1 exceeding short int.\n");
+    #endif
+
+    width += pDstDrawable->x + dstx + 32768;
+    srcx  -= pDstDrawable->x + dstx + 32768;
+    dstx = -32768 - pDstDrawable->x;
+
+    if (width <= 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentCopyArea: Returning null on x1 check.\n");
+      #endif
+
+      return NullRegion;
+    }
+  }
+
+    oldDstxyValue = dsty;
+
+  if (dsty + pDstDrawable->y + height > 32767)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentCopyArea: y2 exceeding short int.\n");
+    #endif
+
+    height = 32767 - dsty - pDstDrawable->y;
+
+    if (height <= 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentCopyArea: Returning null on y2 check.\n");
+      #endif
+
+      return NullRegion;
+    }
+  }
+
+  if (dsty + pDstDrawable->y < -32768)
+  {
+    #ifdef WARNING
+    fprintf(stderr, "nxagentCopyArea: y1 exceeding short int.\n");
+    #endif
+
+    height += 32768 + pDstDrawable->y + dsty;
+    srcy   -= 32768 + pDstDrawable->y + dsty;
+    dsty = -32768 - pDstDrawable->y;
+
+    if (height <= 0)
+    {
+      #ifdef TEST
+      fprintf(stderr, "nxagentCopyArea: Returning null on y1 check.\n");
+      #endif
+
+      return NullRegion;
+    }
+  }
+
+
   if (nxagentGCTrap == 1 || nxagentShmTrap == 1)
   {
     if (pSrcDrawable -> type == DRAWABLE_PIXMAP &&