Merge branch 'earlynull.AthContainers-20240518' into 'main'

AthContainers: Early exit from Factory operations for 0 elements.

See merge request !71504

Control/AthContainers/AthContainers/tools/AuxTypeVectorFactory.icc

 /*
-  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 */
 /**
  * @file AthContainers/tools/AuxTypeVectorFactory.icc
@@ -168,6 +168,7 @@ AuxTypeVectorFactoryImpl<T, ALLOC>::copyImpl (SG::auxid_t auxid,
                                               size_t src_index,
                                               size_t n) const -> vector_value_type*
 {
+  if (n == 0) return nullptr;
   auto dstptr = reinterpret_cast<vector_value_type*>(dst.getDataArray (auxid));
   if (&src == &dst) {
     // Source and destination containers are the same.
@@ -263,6 +264,7 @@ void AuxTypeVectorFactoryImpl<T, ALLOC>::swap (SG::auxid_t auxid,
                                                AuxVectorData& b, size_t bindex,
                                                size_t n) const
 {
+  if (n == 0) return;
   auto aptr = reinterpret_cast<vector_value_type*>(a.getDataArray (auxid));
   auto bptr = &a == &b ? aptr : reinterpret_cast<vector_value_type*>(b.getDataArray (auxid));
   for (size_t i = 0; i < n; i++) {
@@ -284,6 +286,7 @@ void AuxTypeVectorFactoryImpl<T, ALLOC>::clear (SG::auxid_t auxid,
                                                 size_t dst_index,
                                                 size_t n) const
 {
+  if (n == 0) return;
   auto ptr = reinterpret_cast<vector_value_type*>(dst.getDataArray (auxid));
   std::fill (ptr+dst_index, ptr+dst_index+n, SG::Zero<vector_value_type>::zero());
 }

Control/AthContainersRoot/src/RootAuxVectorFactory.cxx

@@ -481,6 +481,7 @@ char* RootAuxVectorFactory::copyImpl (SG::auxid_t auxid,
                                       size_t src_index,
                                       size_t n) const
 {
+  if (n == 0) return nullptr;
   size_t eltsz = m_type.getSize();
   char* dstptr = reinterpret_cast<char*> (dst.getDataArray (auxid));
   if (&src == &dst) {
@@ -586,6 +587,7 @@ void RootAuxVectorFactory::swap (SG::auxid_t auxid,
                                  AuxVectorData& b, size_t bindex,
                                  size_t n) const
 {
+  if (n == 0) return;
   void* aptr = a.getDataArray (auxid);
   void* bptr = &a == &b ? aptr : b.getDataArray (auxid);
   m_type.swapRange (aptr, aindex, bptr, bindex, n);
@@ -603,6 +605,7 @@ void RootAuxVectorFactory::clear (SG::auxid_t auxid,
                                   AuxVectorData& dst, size_t dst_index,
                                   size_t n) const
 {
+  if (n == 0) return;
   m_type.clearRange (dst.getDataArray (auxid), dst_index, n);
 }
 

Control/xAODRootAccess/Root/TAuxVectorFactory.cxx

-// Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
+// Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
 
 // ROOT include(s):
 #include <TClass.h>
@@ -78,6 +78,8 @@ namespace xAOD {
                                  const SG::AuxVectorData& src,  size_t src_index,
                                  size_t n ) const {
 
+      if (n == 0) return;
+
       // The size of one element in memory:
       const size_t eltsz = m_proxy->GetIncrement();
 
@@ -137,6 +139,8 @@ namespace xAOD {
                                  SG::AuxVectorData& b, size_t bindex,
                                  size_t n ) const {
 
+      if (n == 0) return;
+
       // The size of one element in memory:
       const size_t eltsz = m_proxy->GetIncrement();
 
@@ -192,6 +196,8 @@ namespace xAOD {
                                   size_t dst_index,
                                   size_t n ) const {
 
+      if (n == 0) return;
+
       // The size of one element in memory:
       const size_t eltsz = m_proxy->GetIncrement();