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Table of Contents

Package Xtc

The Xtc package defines several classes.

Class XtcFileIterator

An xtc file is a collection of datagrams (Dgram). This is an iterator to loop through all datagrams in a file.

Public Member Functions:

Code Block
  // Constructor and destructor
  XtcFileIterator(int fd, size_t maxDgramSize);

  Dgram* next();

Class Dgram

Datagram - structure of a piece of information within the xtc file.
A datagram contains: Sequence, Env and Xtc.

Code Block
   |                  |                 |
 Sequence         Env                 Xtc

Public Attributes:

Code Block
     PDS_DGRAM_STRUCT // #define PDS_DGRAM_STRUCT Sequence seq; Env env; Xtc xtc

Class Sequence

Defined in pdsdata/xtc/Sequence.hh.

Public Types:

Code Block
    enum Type    {Event = 0, Occurrence = 1, Marker = 2};
    enum         {NumberOfTypes = 3};

Public Member Functions:

Code Block
    // Constructors
    Sequence() {}
    Sequence(const Sequence&);
    Sequence(const ClockTime& clock, const TimeStamp& stamp);
    Sequence(Type, TransitionId::Value, const ClockTime&, const TimeStamp&);

    Type type() const;
    TransitionId::Value  service() const;
    bool isExtended() const;
    bool isEvent() const;
    const ClockTime& clock() const {return _clock;}
    const TimeStamp& stamp() const {return _stamp;}

    Sequence& operator=(const Sequence&);

Class Env

Defined in pdsdata/xtc/Env.hh

Public Member Functions

Code Block
    // Constructors
    Env() {}
    Env(const Env& in) : _env(in._env) {}
    Env(uint32_t env);

    uint32_t value() const;

    const Env& operator=(const Env& that);

Class Xtc

This class defines a container for data stored in an xtc file. An event is a collection of such containers. The size and location of the unspecified data contained are defined by the "sizeofPayload" and "payload" functions. To iterate over a set of such containers see "XtcIterator.hh".

Public Member Functions:

Code Block
    //Constructor used to create an empty, unlabeled
    Xtc() : damage(0), extent(0) {};

    // Copy constructor, will copy everything, but NOT the payload.
    Xtc(const Xtc& xtc) :
      damage(xtc.damage), src(xtc.src), contains(xtc.contains), extent(sizeof(Xtc)) {}

    Xtc(const TypeId& type) :
      damage(0), contains(type), extent(sizeof(Xtc)) {}

    Xtc(const TypeId& type, const Src& _src) :
      damage(0), src(_src), contains(type), extent(sizeof(Xtc)) {}

    Xtc(const TypeId& _tag, const Src& _src, unsigned _damage) :
      damage(_damage), src(_src), contains(_tag), extent(sizeof(Xtc)) {}

    Xtc(const TypeId& _tag, const Src& _src, const Damage& _damage) :
      damage(_damage), src(_src), contains(_tag), extent(sizeof(Xtc)) {}

Overloaded allocation operators to allow the insertion of a dummy "Xtc" within a datagram.

Code Block
    void* operator new(size_t size, char* p)     { return (void*)p; }
    void* operator new(size_t size, Xtc* p)      { return p->alloc(size); }
Code Block
    // Return a pointer (of unspecified type) to the payload associated with this class
    char*        payload()       const { return (char*)(this+1); }

    // Return the size (in bytes) of the payload associated with the class.
    int          sizeofPayload() const { return extent - sizeof(Xtc); }

    // Return the Xtc which is immediately following an object of this class.
    Xtc*       next()                { return (Xtc*)((char*)this+extent); }
    const Xtc* next()          const { return (const Xtc*)((char*)this+extent); }

    void*      alloc(uint32_t size)  { void* buffer = next(); extent += size; return buffer; }

Public Attributes:

Code Block
    Damage   damage;
    Src      src;
    TypeId   contains;
    uint32_t extent;

Class XtcIterator

This class allows iteration over a collection of "Xtc" objects. An "event" generated from DataFlow consists of data described by a collection of "Xtc" objects. Therefore, this class is instrumental in the navigation of an event's data. The set of "Xtc"s is determined by passing (typically to the constructor) a root "Xtc" which describes the collection of "Xtc"s to process. This root, for example is provided by an event's datagram.

As this is an Abstract-Base-Class, it is expected that an application will subclass from this class, providing an implementation of the "process" method. This method will be called back for each "Xtc" in the collection. Note that the "Xtc" to process is passed as an argument. If the "process" method wishes to abort the iteration a zero (0) value is returned. The iteration is initiated by calling the "iterate" member function.

Public Member Functions:
Constructors and destructor:

Code Block
    XtcIterator(Xtc* root);
    XtcIterator() {}
    virtual ~XtcIterator() {}

The first constructor takes an argument the "Xtc" which defines the collection to iterate over.

Code Block
    virtual int process(Xtc* xtc) = 0;

This function is pure virtual and must be implemented by all derived classes.

Code Block
    void      iterate();

This function commences iteration over the collection specified by the constructor.

Code Block
    void      iterate(Xtc*);

Iterate over the collection specifed as an argument to the function. For each "Xtc" found call back the "process" function. If the "process" function returns zero (0) the iteration is aborted and control is returned to the caller. Otherwise, control is returned when all elements of the collection have been scanned.

Code Block
    const Xtc* root()  const;

This function returns the collection specified by the constructor.

Class Level

Defined in pdsdata/xtc/Level.hh

Public Types:

Code Block
  enum Type{Control, Source, Segment, Event, Recorder, Observer, Reporter,

Static Public Member Functions

Code Block
  static const char* name(Type type);

Class TransitionId

Public Types:

Code Block
    enum Value {
      Unknown, Reset,
      Map, Unmap,
      Configure, Unconfigure,
      BeginRun, EndRun,
      BeginCalibCycle, EndCalibCycle,
      Enable, Disable,
      NumberOf };

Static Public Member Functions:

Code Block
    static const char* name(TransitionId::Value id);

Class Src

This is a base class for any source of information in the xtc file (e.g. Detector, Beamline, Process). Defined in pdsdata/xtc/Src.hh

Public Member Functions:

Code Block
    // Constructors
    Src(Level::Type level);

    uint32_t log()   const;    // logical identifier
    uint32_t phy()   const;    // physical identifier

    Level::Type level() const; // level

    bool operator==(const Src& s) const;

Protected Attributes

Code Block
    uint32_t _log; // logical  identifier
    uint32_t _phy; // physical identifier

Class BldInfo

Beamline data Information. This is a derived class that inherits from Src.
Defined in pdsdata/xtc/BldInfo.hh

Public Types:

Code Block
    enum Type { EBeam = 0, PhaseCavity = 1, FEEGasDetEnergy = 2, NumberOf = 3 };

Public Member Functions

  • Constructors and Destructor
    Code Block
        BldInfo() {}
        BldInfo(uint32_t processId, Type type);
  • Accessors
    Code Block
        uint32_t processId() const;
        Type     type()  const;

Static Public Member Functions

Code Block
    static const char* name(const BldInfo&);

Class ProcInfo

Process information class. This is a derived class that inherits from Src.
Holds process info for all Levels except Source.

Public Member Functions:

Code Block
    // Constructor
    ProcInfo(Level::Type level,     //
             uint32_t processId,    //
             uint32_t ipAddr);      //

    uint32_t processId() const;
    uint32_t ipAddr()    const;
    void     ipAddr(int);

Class DetInfo

Detector information. Inherits from Src. Defined in pdsdata/xtc/DetInfo.hh and implemented in pdsdata/xtc/src/

Public Types:

Code Block
    enum Detector {
      NoDetector    = 0,
      AmoIms        = 1,  // AMO Ion Momentum Spectrometer
      AmoGasdet     = 2,  // AMO Gas Detector (in FrontEnd Enclosure)
      AmoETof       = 3,  // AMO Electron Time-of-flight
      AmoITof       = 4,  // AMO Ion Time-of-flight
      AmoMbes       = 5,  // AMO Magnetic bottle electron spectrometer
      AmoVmi        = 6,  // AMO Velocity map imaging
      AmoBps        = 7,  // AMO Beam position screen
      Camp          = 8,  // CFel-ASG-Multi-Purpose EndStation
      EpicsArch     = 9,  //
      BldEb         = 10,
      SxrBeamline   = 11,
      SxrEndstation = 12,
      XppSb1Ipm     = 13,
      XppSb1Pim     = 14,
      XppMonPim     = 15,
      XppSb2Ipm     = 16,
      XppSb3Ipm     = 17,
      XppSb3Pim     = 18,
      XppSb4Pim     = 19,
      XppGon        = 20,
      XppLas        = 21,
      XppEndstation = 22,
      AmoEndstation = 23,
      CxiEndstation = 24,
      XcsEndstation = 25,
      MecEndstation = 26,
      NumDetector   = 27
    enum Device {
      NoDevice  = 0,
      Evr       = 1,
      Acqiris   = 2,
      Opal1000  = 3,
      TM6740    = 4,
      pnCCD     = 5,
      Princeton = 6,
      Fccd      = 7,
      Ipimb     = 8,
      Encoder   = 9,
      Cspad     = 10,
      NumDevice = 11

Public Member Functions

Code Block
    // Constructors
    DetInfo() {}
    DetInfo(uint32_t   processId,   //
            Detector   det,         //
            uint32_t   detId,       //
            Device     dev,         //
            uint32_t   devId);      //

    bool operator==(const DetInfo &) const;

    uint32_t processId() const;
    Detector detector() const;
    Device device() const;
    uint32_t detId() const;
    uint32_t devId() const;

Static Public Member Functions

Code Block
    static const char *name(Detector);
    static const char *name(Device);
    static const char *name(const DetInfo &);

Class ClockTime

Defined in pdsdata/xtc/ClockTime.hh.

Public Member Functions:

  • Constructors (ClockTime has no destructor)
    Code Block
        ClockTime(const ClockTime& t);
        ClockTime(unsigned sec, unsigned nsec);
  • Accessors:
    Code Block
        unsigned seconds    () const {return _high;}
        unsigned nanoseconds() const {return _low;}
  • Operators
    Code Block
        ClockTime& operator=(const ClockTime&);
        bool operator> (const ClockTime&) const;
        bool operator==(const ClockTime&) const;

Class Damage

Defined in pdsdata/xtc/Damage.hh, inline implementation.

Public Types:

Code Block
    enum Value {
      DroppedContribution    = 1,
      OutOfOrder             = 12,
      OutOfSynch             = 13,
      UserDefined            = 14,
      IncompleteContribution = 15,
      ContainsIncomplete     = 16
    // reserve the top byte to augment user defined errors
    enum {NotUserBitsMask=0x00FFFFFF, UserBitsShift = 24};
  • DroppedContribution - means that event is "split" and contains only partial data from incomplete set of detectors. There may be another (or even few) datagram with the same timestamp containing remaining data from the same event.
  • OutOfOrder - In this case the event may contain data from one or more detector which actually belong to a different event.
  • OutOfSynch
  • UserDefined - reserved for user-defined conditions
  • IncompleteContribution - means that data in that particular container is badly damaged, are incomplete, and cannot be used
  • ContainsIncomplete - means that it contains one or more containers at deeper XTC levels which have IncompleteContribution damage, events with this damage may be partially useful
Code Block
Bit   Mask   Name
 1  0x00002  DroppedContribution
12  0x01000  OutOfOrder
13  0x02000  OutOfSynch
14  0x04000  UserDefined
15  0x08000  IncompleteContribution
16  0x10000  ContainsIncomplete

Bit = n means 1<<n, i.e. 1 shifted left n bits:

                    Decimal     Binary
int32_t value =     1           00000000000000000000000000000001
                                |       |       |       |
DroppedContribution             00000000000000000000000000000010
OutOfOrder                      00000000000000000001000000000000
OutOfSynch                      00000000000000000010000000000000
UserDefined                     00000000000000000100000000000000
IncompleteContribution          00000000000000001000000000000000
ContainsIncomplete              00000000000000010000000000000000

Public Member Functions:

Code Block
    // Constructor
    Damage(uint32_t v) : _damage(v) {}

    uint32_t  value() const             { return _damage; }
    void     increase(Damage::Value v)  { _damage |= ((1<<v) & NotUserBitsMask); }
    void     increase(uint32_t v)       { _damage |= v & NotUserBitsMask; }
    uint32_t bits() const               { return _damage & NotUserBitsMask;}
    uint32_t userBits() const           { return _damage >> UserBitsShift; }
    void     userBits(uint32_t v) {
      _damage &= NotUserBitsMask;
      _damage |= (v << UserBitsShift);

Class TimeStamp

Public Types:

Code Block
    enum {NumFiducialBits = 17};
    enum {MaxFiducials = (1<<17)-32};
    enum {ErrFiducial = (1<<17)-1};

Public Member Functions:

Code Block
    TimeStamp(const TimeStamp&);
    TimeStamp(const TimeStamp&, unsigned control);
    TimeStamp(unsigned ticks, unsigned fiducials, unsigned vector, unsigned control=0);

    unsigned ticks    () const;
    unsigned fiducials() const;
    unsigned control  () const;
    unsigned vector   () const;

    TimeStamp& operator= (const TimeStamp&);
    bool       operator==(const TimeStamp&) const;
    bool       operator>=(const TimeStamp&) const;
    bool       operator<=(const TimeStamp&) const;
    bool       operator< (const TimeStamp&) const;
    bool       operator> (const TimeStamp&) const;

Class TypeId

Public Types:

Code Block
    enum Type {
      Id_Xtc,          // generic hierarchical container
      Id_Frame,        // raw image
      Id_TwoDGaussian, // 2-D Gaussian + covariances
      Id_Epics,        // Epics Data Type
      Id_IpmFexConfig,  // LUSI Diagnostics

Public Member Functions:

Code Block
    TypeId() {}
    TypeId(const TypeId& v);
    TypeId(Type type, uint32_t version);

    Type     id()      const;
    uint32_t version() const;
    uint32_t value()   const;

    static const char* name(Type type);