JROOT/JCounter.hh

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#ifndef __JROOT__JCOUNTER__
#define __JROOT__JCOUNTER__

#include <limits>

#include "Rtypes.h"


/**
 * \file
 *
 * Type definition for counter for ROOT TTree and auxiliary methods.
 * \author mdejong
 */
namespace JROOT {}
namespace JPP { using namespace JROOT; }

namespace JROOT {

  
  /**
   * Type definition for counter.
   */
  typedef Long64_t            counter_type;


  /**
   * Advance counter.
   *
   * \param  counter      counter (I/O)
   * \param  value        offset
   * \param  limit        limit
   * \return              increment
   */
  inline counter_type advance(counter_type&      counter,
                              const counter_type value,
                              const counter_type limit = std::numeric_limits<counter_type>::max())
  {
    const counter_type previous = counter;
        
    if (counter + value < limit)
      counter += value;
    else 
      counter  = limit;
    
    return counter - previous;
  }
}

#endif