Variables.cpp

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#include "cafe/Variables.hpp"

#include "TBranch.h"
#include "TTree.h"

#include <cassert>
#include <stdexcept>

namespace cafe {

    Variables::Variables()
        : _cookie(-1),
          _branch(0)
    {
    }

    Variables::Variables(const std::vector<std::string>& names)
        : _names(names),
          _cookie(-1),
          _branch(0)
    {
    }

    Variables::Variables(const std::string& name1)
        : _names(1, name1),
          _cookie(-1),
          _branch(0)
    {
    }
        
    Variables::Variables(const std::string& name1, const std::string& name2)
        : _cookie(-1),
          _branch(0)
    {
        add(name1);
        add(name2);
    }

    Variables::Variables(const std::string& name1, const std::string& name2, const std::string& name3)
        : _cookie(-1),
          _branch(0)
    {
        add(name1);
        add(name2);
        add(name3);
    }

    Variables::Variables(const std::string& name1, const std::string& name2, const std::string& name3, const std::string& name4)
        : _cookie(-1),
          _branch(0)
    {
        add(name1);
        add(name2);
        add(name3);
        add(name4);
    }

    Variables::Variables(const Variables& other)
        : _names(other._names),
          _subbranches(other._subbranches),
          _cookie(other._cookie),
          _branch(other._branch)
    {
    }
    
    Variables& Variables::operator=(const Variables& other)
    {
        if(this != &other) {
            _names       = other._names;
            _subbranches = other._subbranches;
            _cookie      = other._cookie;
            _branch      = other._branch;
        }
        return *this;
    }

    Variables& Variables::add(const std::string& name)
    {
        _names.push_back(name);
        _cookie = -1;
        _branch = 0;
        return *this;
    }
    
    Variables& Variables::add(const std::vector<std::string>& names)
    {
        _names.insert(_names.end(), names.begin(), names.end());
        _cookie = -1;
        _branch = 0;
        return *this;
    }
    
    Variables::~Variables()
    {
    }

    bool Variables::empty() const
    {
        return _names.empty();
    }

    void Variables::get(TTree *tree, TBranch *br, int cookie) const
    {
        using namespace std;

        assert(tree != 0);
        assert(br != 0);

        if(cookie != _cookie) {

            // TTree has changed, update branch pointers
            // update branch pointers
            _subbranches.clear();
            for(vector<string>::const_iterator it = _names.begin();
                it != _names.end();
                ++it) {
                if(TBranch *subbr = br->FindBranch((*it).c_str())) {
                    _subbranches.push_back(subbr);
                } else {
                    throw runtime_error("Variables: non-existing branch name: " + *it);
                }
            }

            _cookie = cookie;
            _branch = br;
        }

        if(_branch != br) {
            throw std::logic_error(std::string("Variables: using same object for two different branches: ") +
                                   _branch->GetName() + " and " + br->GetName());
        }
        
        // Read the variables if they are not yet in memory
        Long64_t current = tree->GetReadEntry();
        for(vector<TBranch*>::iterator it = _subbranches.begin();
            it != _subbranches.end();
            ++it) {
            if((*it)->GetReadEntry() != current) {
                (*it)->GetEntry(current);
            }
        }
    }

}

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