examples/analysistools/compress.C

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#include "TFile.h"
#include "TTree.h"
#include "TString.h"
#include "TEventList.h"
#include "TDirectory.h"
#include <iostream>
#include "TObjArray.h"
#include "TRegexp.h"
#include <vector>

typedef std::vector<TString> StrVec;

int COMSplitString(TString s, TString delim, StrVec &toks)
{
        toks.clear();
        TObjArray *tok = s.Tokenize(delim);
        int N = tok->GetEntries();      
        for (int i=0;i<N;++i) 
        {
                TString token = (((TObjString*)tok->At(i))->String()).Strip(TString::kBoth);
                toks.push_back(token);
        }
        return toks.size();
}

int compress(TString ntp="", TString fnamein="", TString fnameout="", TString bnames="", TString precut="" )
{
        if (ntp=="" || fnamein=="" || fnameout=="")
        {
                cout <<"USAGE:\ncompress(TString tree, TString infile, TString outfile, TString bnames, TString precut)\n\n"; 
                cout <<"  tree    : name of the TTree to be compressed.\n";
                cout <<"  infile  : input file name.\n";
                cout <<"  outfile : output file name.\n";
                cout <<"  bnames  : blank separated list of branch variable names to be copied; can make use of name* / *name /*name*; !(*)name(*) excludes variables (default = \"*\").\n";
                cout <<"  precut  : cut to be applied before compressing branches (default = \"\"). Either bnames!=\"*\" or precut!=\"\".\n\n";
        
                return;
        }
        
        if (bnames=="*" && precut=="") 
        {
                cout <<"Nothing to compress. Exiting."<<endl;
                return;
        }
        
        // do preselection
        TFile *fi = new TFile(fnamein,"READ");
        TTree *ti = (TTree*) fi->Get(ntp);
        ti->Draw(">>el",precut);
        
        // Separate names of branches to be considered
        StrVec bnam;
        COMSplitString(bnames," ", bnam);
        
        // Enable/disable branches
        ti->SetBranchStatus("*",0);
        for (uint i=0;i<bnam.size();++i)
                if (bnam[i].BeginsWith("!")) ti->SetBranchStatus(TString(bnam[i](1,1000)),0);
                else ti->SetBranchStatus(bnam[i],1);
                
        bnam.clear();
        TObjArray* blist = ti->GetListOfBranches();
        for(int i=0; i<=blist->GetLast(); ++i)
        {
                TString name = ((TBranch*)blist->UncheckedAt(i))->GetName();
                if (ti->GetBranchStatus(name)>0) bnam.push_back(name); 
        }
        
        // print selected branches
        cout<<"**** Branch pattern: \""<<bnames<<"\""<<endl;
        cout<<"**** "<<bnam.size()<<" branches found: \n";
        for (uint i=0;i<bnam.size();++i) printf("%s  ",bnam[i].Data());
        cout <<endl<<endl;
                
        cout <<"Converting tree '"<<ntp<<"': "<<fnamein<<" ("<<ti->GetNbranches()<<" br, "<<ti->GetEntriesFast()<<" ev) ... "<<flush;

        TEventList *el = (TEventList*)gDirectory->Get("el");
        ti->SetEventList(el);
        
        TFile *fo = new TFile(fnameout, "RECREATE");    
        TTree *to = ti->CopyTree("");
        
        cout <<"to "<<fnameout<<" ("<<to->GetNbranches()<<" br, "<<to->GetEntriesFast()<<" ev) "<<endl;
        
        fo->Write();
        fo->Close();
        fi->Close();
  return 0;
}