ClusterID.h

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
 
#ifndef ALICEO2_ITSMFT_CLUSTERID_H
#define ALICEO2_ITSMFT_CLUSTERID_H
 
namespace o2::itsmft
{
 
// max number of layers for which the ITS/MFT clusters, ROF records and patterns can be provided separately
constexpr int MaxITSClusLayers = 7;
constexpr int MaxMFTClusLayers = 10;
constexpr int MaxClusLayers = MaxITSClusLayers > MaxMFTClusLayers ? MaxITSClusLayers : MaxMFTClusLayers;
 
constexpr int ClusLayerShift = 27;
constexpr int ClusIndexMask = (0x1 << ClusLayerShift) - 1;
static_assert((1 << (31 - ClusLayerShift)) >= MaxClusLayers, "ClusLayerShift leaves no room for the layer ID");
 
constexpr int composeClusID(int lr, int idx) { return (lr << ClusLayerShift) + idx; }
constexpr int clusID2Layer(int id) { return id >> ClusLayerShift; }
constexpr int clusID2Index(int id) { return id & ClusIndexMask; }
 
} // namespace o2::itsmft
 
#endif