VXDElectronDeposit.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <algorithm>
#include <cmath>
 
namespace Belle2 {
  class VXDElectronDeposit {
  public:
    enum EBits {
      c_FractionBits = 10,
      c_ElectronBits = 22,
      c_TotalBits = c_FractionBits + c_ElectronBits,
      c_MaxFraction = (1 << c_FractionBits) - 1,
      c_MaxElectrons = (1 << c_ElectronBits) - 1,
    };

    explicit VXDElectronDeposit(unsigned int packed): m_packed(packed) {}

    VXDElectronDeposit(float fraction, float electrons)
    {
      const unsigned int intfrac = std::round(std::max(0.f, fraction) * static_cast<float>(c_MaxFraction));
      const unsigned int intelec = std::round(std::max(0.f, electrons));
      m_packed = std::min(intfrac, static_cast<unsigned int>(c_MaxFraction))
                 + (std::min(intelec, static_cast<unsigned int>(c_MaxElectrons)) << c_FractionBits);
    }

    float getFraction() const
    {
      return (m_packed & c_MaxFraction) * 1.0 / static_cast<float>(c_MaxFraction);
    }

    unsigned int getElectrons() const
    {
      return (m_packed >> c_FractionBits) & c_MaxElectrons;
    }

    unsigned int getPacked() const { return m_packed; }
    operator unsigned int() const { return m_packed; }
  private:
  unsigned int m_packed: c_TotalBits;
  };

} //Belle2 namespace