Jpp 19.3.0-rc.3
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JROOT::JTreeBranchAddresses< T > Class Template Reference

Class responsible to setup TTree branch addresses for reading objects of type T. More...

#include <JTreeBranchAddresses.hh>

Inheritance diagram for JROOT::JTreeBranchAddresses< T >:
JROOT::JRootAddress< T > JROOT::JTreeReader< T > JROOT::JTreeReaderObjectIterator< T > JROOT::JTreeReaderAccessibleObjectIterator< T > JROOT::JRootFileReader< T, true >

Public Member Functions

void setBranchAddress (TTree &tree)
 
void release ()
 Release memory.
 
T * getAddress () const
 Get address.
 

Protected Attributes

T * address
 

Detailed Description

template<typename T>
class JROOT::JTreeBranchAddresses< T >

Class responsible to setup TTree branch addresses for reading objects of type T.

Definition at line 39 of file JTreeBranchAddresses.hh.

Member Function Documentation

◆ setBranchAddress()

template<typename T >
void JROOT::JTreeBranchAddresses< T >::setBranchAddress ( TTree & tree)
inline

Definition at line 53 of file JTreeBranchAddresses.hh.

54 {
55 TObjArray* branches = tree.GetListOfBranches();
56 // single branch
57 if (branches->GetEntries() == 1) {
58 tree.SetBranchAddress(branches->First()->GetName(), &this->address);
59 return;
60 }
61
62 // if more than one branch, check those are the data members of T
63 TClass* t_class = TClass::GetClass<T>();
64 if (t_class == nullptr) {
65 THROW(JException, "Could not get class " << typeid(T).name());
66 }
67
68 auto branch_names = to_vector(tree.GetListOfBranches());
69 auto all_member_names = to_vector(t_class->GetListOfRealData());
70
71 std::vector<std::string> member_names;
72
73 // remove TObject specific members
74 std::copy_if(all_member_names.begin(), all_member_names.end(), std::back_inserter(member_names),
75 [](const std::string& member_name)
76 { return !JRoot::is_tobject_member(member_name.c_str()); });
77
78 std::sort(branch_names.begin(), branch_names.end());
79 std::sort(member_names.begin(), member_names.end());
80
81 // all members must have a corresponding branch
82 // (but more branches are allowed, we just don't handle them here)
83 if (std::includes(branch_names.begin(), branch_names.end(), member_names.begin(),
84 member_names.end())) {
85
86 this->address = new T;
87
88 auto* base = reinterpret_cast<uint8_t*>(this->address);
89
90 for (const auto& member_name : member_names) {
91 auto* member = static_cast<TDataMember*>(t_class->GetDataMember(member_name.c_str()));
92 tree.SetBranchAddress(member_name.c_str(),
93 reinterpret_cast<void*>(base + member->GetOffset()));
94 }
95 return;
96 }
97
98 // if we cannot configure the tree, try to give some relevant information
99 // to the user who will have to deal with the exception...
100 THROW(JException, "Members of type " << typeid(T).name() << "\n"
101 << JEEP::JEEPZ() << member_names << "\nBranches in tree\n"
102 << JEEP::JEEPZ() << branch_names);
103 }
#define THROW(JException_t, A)
Marco for throwing exception with std::ostream compatible message.
std::vector< std::string > to_vector(TCollection *col)
Auxiliary data structure for streaming of STL containers.

◆ release()

template<class T >
void JROOT::JRootAddress< T >::release ( )
inlineinherited

Release memory.

Definition at line 54 of file JRootAddress.hh.

55 {
56 if (address != NULL) {
57
58 delete address;
59
60 address = NULL;
61 }
62 }

◆ getAddress()

template<class T >
T * JROOT::JRootAddress< T >::getAddress ( ) const
inlineinherited

Get address.

Returns
address

Definition at line 70 of file JRootAddress.hh.

71 {
72 return address;
73 }

Member Data Documentation

◆ address

template<class T >
T* JROOT::JRootAddress< T >::address
protectedinherited

Definition at line 76 of file JRootAddress.hh.


The documentation for this class was generated from the following file: