Hello Rooters,
I have a question concerning Root Trees. My Problem is the following. I have a class Structure that I want to serialize into a Root Tree.
I have been reading the User Manual and serveral tutorials, but I did not find the answer to my specific question.
My Class Structure is as follows:
I have a class MyEvent that contains a std::vector containing Channels. Each Channel has a vector
containing pointers to MyPuls. Each MyPuls has an array of chars. Here is the code
class MyEvent
{ //several other data members and member functions//
std::vector<MyChannel*> channels; //vector of Pointers to MyChannel
}
class MyChannel
{ //several other data members and member functions//
std::vector<MyPuls*> pulses; //vector containing pointers to pulses
}
class MyPuls
{ //several other data members and member functions//
void * data; //pointer to the waveform
long length; //length of the waveform
}Most of the other data Members I want to store in a Header, since they won’t change and I don’t
want to store them for each event to reduce memory space.
If I would serialize this structure to a binary file I would do the following:
first store a header with all the information from MyEvent, MyChannel, MyPuls
void MyEvent::serialize()
{
out << channels.size(); // the current nbr of channels
for (int i=0; i<channels.size();++i)
channels[i]->serialize();
}
void MyChannel::serialize()
{
out << pulses.size(); //current nbr of Pulses in Channel
for (int i=0; i<pulses.size(); ++i)
pulses[i]->serialize();
}
void MyPuls::serialize()
{
out << length; //the waveform length
out.write((char*)data,length);
}How do I have to modify the serialize functions in order to serialize this structure to a Root Tree?
Unfortunatly I cannot do it the way that is described in Tutorial root.cern.ch/root/html/examples/ … t.cxx.html, because
the Data Members in this structure will change very often, and if one wants to read the root file
one has to have the version of the structure when the root file was written. To avoid this problem, it would
be nice if one could extract the data without knowing the data structure by just going through the branches
and get the data members.
Is this possible and how can I do that?
Thank you,
Lutz