DTCELinkId.h

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#ifndef CondFormats_Phase2TrackerDTC_DTCELinkId_h
#define CondFormats_Phase2TrackerDTC_DTCELinkId_h

// -*- C++ -*-
//
// Package:    CondFormats/Phase2TrackerDTC
// Class:      DTCELinkId
// 
//
// Original Author:  Luigi Calligaris, SPRACE, Sao Paulo, BR
// Created        :  Wed, 27 Feb 2019 21:41:13 GMT
//
//

#include <cstdint>
#include <limits>

#include "CondFormats/Serialization/interface/Serializable.h"

class DTCELinkId
{
public:
    DTCELinkId() noexcept;
    DTCELinkId(DTCELinkId const&) noexcept;
    DTCELinkId(DTCELinkId&&) noexcept;
    DTCELinkId& operator=(DTCELinkId const&) noexcept;
    DTCELinkId& operator=(DTCELinkId&&) noexcept;
    ~DTCELinkId() noexcept;
    
    // Constructs a DTCELinkId addressed by (dtc_id, gbtlink_id, elink_id)
    DTCELinkId(uint16_t,uint8_t,uint8_t) noexcept;
    
    inline auto elink_id()   const noexcept {return elink_id_  ;}
    inline auto gbtlink_id() const noexcept {return gbtlink_id_;}
    inline auto dtc_id()     const noexcept {return dtc_id_    ;}
    
private:
    // In order to keep the payload small, we use the C standard integers, optimizing them for size.
    // The lpGBT has at most 7 ePorts, therefore they can be addressed by an 8-bit number.
    // The DTC should host at most 72 GBT links, therefore an 8-bit number should be enough to address it.
    // The C++ memory alignment and padding rules impose that this class will have at least 32 bits size,
    // i.e. 8+8+8 bits and 8+8+16 would be the same, so we choose the latter.
    uint8_t  elink_id_  ;
    uint8_t  gbtlink_id_;
    uint16_t dtc_id_    ;
    
    COND_SERIALIZABLE;
};

namespace std
{
    template <>
    struct hash<DTCELinkId>
    {
        size_t operator()(const DTCELinkId& k) const noexcept
        {
            // With 
            constexpr const size_t shift_gbtlink_id =  numeric_limits< decltype( k.elink_id()   ) >::max() + 1u;
            constexpr const size_t shift_dtc_id     = (numeric_limits< decltype( k.gbtlink_id() ) >::max() + 1u) * shift_gbtlink_id;
            
            return k.elink_id() + k.gbtlink_id() * shift_gbtlink_id + k.dtc_id() * shift_dtc_id;
        }
    };
}

inline bool operator< (DTCELinkId const& lhs, DTCELinkId const& rhs) {return lhs.dtc_id() <  rhs.dtc_id() || (lhs.dtc_id() == rhs.dtc_id() && lhs.gbtlink_id() <  rhs.gbtlink_id()) || (lhs.dtc_id() == rhs.dtc_id() && lhs.gbtlink_id() == rhs.gbtlink_id() && lhs.elink_id() <  rhs.elink_id());}
inline bool operator> (DTCELinkId const& lhs, DTCELinkId const& rhs) {return lhs.dtc_id() >  rhs.dtc_id() || (lhs.dtc_id() == rhs.dtc_id() && lhs.gbtlink_id() >  rhs.gbtlink_id()) || (lhs.dtc_id() == rhs.dtc_id() && lhs.gbtlink_id() == rhs.gbtlink_id() && lhs.elink_id() >  rhs.elink_id());}
inline bool operator==(DTCELinkId const& lhs, DTCELinkId const& rhs) {return lhs.dtc_id() == rhs.dtc_id() && lhs.gbtlink_id() == rhs.gbtlink_id() && lhs.elink_id() == rhs.elink_id();}
inline bool operator!=(DTCELinkId const& lhs, DTCELinkId const& rhs) {return lhs.dtc_id() != rhs.dtc_id() || lhs.gbtlink_id() != rhs.gbtlink_id() || lhs.elink_id() != rhs.elink_id();}


#endif // end DataFormats_Phase2TrackerDTC_DTCELinkId_h