tdf#163691 Use std::copy_n() instead of memcpy() in editeng

Replace memcpy() with std::copy_n() in impedit3.cxx to improve
type safety by eliminating manual sizeof() calculations.

Change-Id: I8f0dc51007f211dbf22689a2a50916657d0c53f4
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/204357
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>
Tested-by: Jenkins

editeng/source/editeng/impedit3.cxx

@@ -78,6 +78,7 @@
 #include <o3tl/sorted_vector.hxx>
 #include <osl/diagnose.h>
 #include <comphelper/string.hxx>
+#include <algorithm>
 #include <cstddef>
 #include <memory>
 
@@ -4990,7 +4991,7 @@ void ImpEditEngine::ImplExpandCompressedPortions(EditLine& rLine, ParaPortion& r
             DBG_ASSERT( nTxtPortionStart >= rLine.GetStart(), "Portion doesn't belong to the line!!!" );
             double* pDXArray = rLine.GetCharPosArray().data() + (nTxtPortionStart - rLine.GetStart());
             if ( pTP->GetExtraInfos()->pOrgDXArray )
-                memcpy( pDXArray, pTP->GetExtraInfos()->pOrgDXArray.get(), (pTP->GetLen()-1)*sizeof(double) );
+                std::copy_n( pTP->GetExtraInfos()->pOrgDXArray.get(), pTP->GetLen()-1, pDXArray );
             ImplCalcAsianCompression( rParaPortion.GetNode(), pTP, nTxtPortionStart, pDXArray, static_cast<sal_uInt16>(nCompressPercent), true );
         }
     }