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The Xtc package defines several classes.

Class Xtc

This class defines a container for data stored in an 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:
Constructors:

datagrams (Dgram).
A datagram contains: Sequence, Env and Xtc.

    //Constructor  used to create an empty, unlabeled 
    Xtc()Dgram
 : 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)) {}

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

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

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:
Constructors:

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

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

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

    void* operator new(size_t size, char* p) //
    Xtc(const TypeId& type) :
    { return (void*)p; }
damage(0), contains(type), extent(sizeof(Xtc)) {}

    void* operator new(size_t size, Xtc* p) Xtc(const TypeId& type, const Src& _src) :
     { return p->alloc(size); }

    // Return a pointer (of unspecified type) to the payload associated with this classdamage(0), src(_src), contains(type), extent(sizeof(Xtc)) {}

    Xtc(const TypeId& _tag, const Src& _src, unsigned _damage) :
    char*  damage(_damage), src(_src),     payload()       const { return (char*)(this+1); contains(_tag), extent(sizeof(Xtc)) {}

    // Return the size (in bytes) of the payload associated with the class.Xtc(const TypeId& _tag, const Src& _src, const Damage& _damage) :
    int  damage(_damage),        sizeofPayload() const { return extent - src(_src), contains(_tag), extent(sizeof(Xtc);) {}

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

    //void* Return the Xtc which is immediately following an object of this class.operator new(size_t size, char* p)     { return (void*)p; }
    Xtcvoid* operator new(size_t size,    next(Xtc* p)                { return (Xtc*)((char*)this+extent)p->alloc(size); }

    const// Xtc* next()          const { return (const Xtc*)((char*)this+extent); }

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

Public Attributes:

    Damage   damage;
    SrcReturn 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      src;
    TypeId   contains;
sizeofPayload() const { return extent - sizeof(Xtc); }

    uint32_t extent;

Class XtcIterator

This is an abstract class.

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:

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

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

    virtual int process(Xtc* xtc) = 0;

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

    void      iterate();

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

    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.

    const Xtc* root()  const;

This function returns the collection specified by the constructor.

// 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:

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

Class XtcIterator

This is an abstract class.

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:

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

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

    virtual int process(Xtc* xtc) = 0;

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

    void      iterate();

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

    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.

    const Xtc* root()  const;

This function returns the collection specified by the constructor.

Class Sequence

Defined in pdsdata/xtc/Sequence.hh.

Public Types:

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

Public Member Functions:

    // 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

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

    uint32_t value() const;

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

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

...

    // Constructors
    DetInfo() {}
    DetInfo(uint32_t   processId,   //
            Detector   det,         //
            DetInfo(uint32_t   processIddetId,       //
            DetectorDevice     detdev,         //
            uint32_t   detId, devId);      //

    bool operator==(const DetInfo &) const;

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

Static Public Member Functions

    static const char *name(Detector);
    static uint32_tconst   devIdchar *name(Device);
    static const //

    bool operator==(const DetInfo &) const;

    uint32_t processId() constchar *name(const DetInfo &);

Class ClockTime

Defined in pdsdata/xtc/ClockTime.hh.

Public Member Functions:

• Constructors (ClockTime has no destructor)

  Code Block
  ClockTime();

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• ClockTime(

...

• const

...

...

• ClockTime& t);

...

• ClockTime(unsigned sec, unsigned nsec);

• Accessors:

• Code Block

...

• unsigned seconds

...

...

...

• (

...

• )

...

...

• const

...

• {return _high;}

...

• unsigned

...

• nanoseconds() const {return _low;}

• Operators

Class ClockTime

Defined in pdsdata/xtc/ClockTime.hh.

Public Member Functions:

• Constructors (ClockTime has no destructor)

  Code Block
  ClockTime& operator=(const ClockTime&); bool ClockTimeoperator> (const ClockTime&) t)const; 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:

• bool operator==(const ClockTime&) const;

Class Damage

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

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:

     

    enum Value {
      DroppedContribution    = 1,
      OutOfOrder         Decimal    = 12,Binary
int32_t value =    OutOfSynch 1           00000000000000000000000000000001
 = 13,
      UserDefined            = 14,
      IncompleteContribution = 15,
   |   ContainsIncomplete    | = 16
    };
 |   // reserve the top byte|
DroppedContribution to augment user defined errors
    enum {NotUserBitsMask=0x00FFFFFF, UserBitsShift = 24};

Public Member Functions:

00000000000000000000000000000010
OutOfOrder      // Constructor
    Damage(uint32_t v) : _damage(v) {}

    uint32_t  value() const 00000000000000000001000000000000
OutOfSynch             { return _damage; }
    void  00000000000000000010000000000000
UserDefined   increase(Damage::Value v)  { _damage |= ((1<<v) & NotUserBitsMask); }
    void     increase(uint32_t v)00000000000000000100000000000000
IncompleteContribution        { _damage |= v & NotUserBitsMask; }
 00000000000000001000000000000000
ContainsIncomplete        uint32_t bits() const    00000000000000010000000000000000

Public Types:

    enum Value {
     { returnDroppedContribution _damage & NotUserBitsMask;}
 = 1,
  uint32_t userBits() const  OutOfOrder         { return _damage >> UserBitsShift;= }12,
     void OutOfSynch    userBits(uint32_t v) {
      _damage &= NotUserBitsMask;13,
      _damageUserDefined |= (v << UserBitsShift);
    }

Class Dgram

Datagram - structure of a piece of information within the xtc file.

Public Attributes:

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

Class Sequence

Defined in pdsdata/xtc/Sequence.hh.

Public Types:

= 14,
      IncompleteContribution = 15,
     enum TypeContainsIncomplete    {Event = 0, Occurrence = 1, Marker = 2};
    enum     16
    };
    // reserve the top byte to augment user defined errors
    enum {NumberOfTypesNotUserBitsMask=0x00FFFFFF, UserBitsShift = 324};

Public Member Functions:

    // ConstructorsConstructor
    Damage(uint32_t v) : Sequence_damage(v) {}

    Sequence(const Sequence&);
    Sequence(const ClockTime& clock, const TimeStamp& stamp);
uint32_t  value() const             { return _damage; }
    void     Sequence(Type, TransitionIdincrease(Damage::Value, const ClockTime&, const TimeStamp&);

 v)  { _damage |= ((1<<v) & NotUserBitsMask); }
    void    Type typeincrease(uint32_t v) const;
       {  TransitionId::Value  service() const;_damage |= v & NotUserBitsMask; }
    booluint32_t isExtendedbits() const;
     bool isEvent() const;
    const ClockTime& clock() const { return _clockdamage & NotUserBitsMask;}
    const TimeStamp& stampuint32_t userBits() const {return _stamp;}

    Sequence& operator=(const Sequence&);

Class Env

Defined in pdsdata/xtc/Env.hh

Public Member Functions

          { return _damage >> UserBitsShift; }
    //void Constructors
    EnvuserBits(uint32_t v) {}
    Env(const Env& in) : _env(in._env) {}  _damage &= NotUserBitsMask;
      _damage |= (v << UserBitsShift);
    Env(uint32_t env);

}

Class Dgram

Datagram - structure of a piece of information within the xtc file.

Public Attributes:

     uint32PDS_DGRAM_t value() const;

    const Env& operator=(const Env& that);STRUCT // #define PDS_DGRAM_STRUCT Sequence seq; Env env; Xtc xtc

Class Level

Defined in pdsdata/xtc/Level.hh

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