#include <iostream>

#include <TComplex.h>
#include <TFile.h>
#include <TTree.h>

class Data {
    public:
        unsigned int          entry;
        unsigned int          twoTimesEntry;
        TComplex              value;
        double                normOfValue;
        std::vector<TComplex> values;
        double                normOfSum;

    ClassDef(Data, 2)
};

#pragma read sourceClass="Data" version="[1]" targetClass="Data" \
             source="unsigned int entry" target="twoTimesEntry" \
             code="{ twoTimesEntry = 2 * onfile.entry; }"
#pragma read sourceClass="Data" version="[1]" targetClass="Data" \
             source="TComplex value" target="normOfValue" \
             code="{ normOfValue = onfile.value.Rho2(); }"
#pragma read sourceClass="Data" version="[1]" targetClass="Data" \
             source="std::vector<TComplex> values" target="normOfSum" \
             code="{ TComplex sum; for (size_t i=0; i<onfile.values.size(); ++i) sum += onfile.values[i]; normOfSum = sum.Rho2(); }"

void
read()
{
    TFile* file = TFile::Open("test.root");

    TTree* tree;
    file->GetObject("tree", tree);

    Data* pData = NULL;
    tree->SetBranchAddress("data", &pData);

    for (unsigned int i=0; i<10; ++i) {
        tree->GetEntry(i);

        std::cout << "tree entry " << pData->entry << " contains " << pData->values.size() << " entries, "
                  << "the entry number times two is " << pData->twoTimesEntry << ", "
                  << "the norm of the value is " << pData->normOfValue << ", "
                  << "the norm of the sum of the values is " << pData->normOfSum << std::endl;
    }

    file->Close();
    delete file;
}