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CRingFragmentItem

Name

CRingFragmentItem -- Encapsulate a EVB_FRAGMENT ring item

Synopsis


       
 class CRingFragmentItem {
}
 : public CRingItem {}
          
  CRingFragmentItem(uint64_t timestamp, uint32_t source, uint32_t payloadSize, const void* pBody, uint32_t barrier = 0);
          
           CRingFragmentItem(const CRingItem& rhs)
          throws std::bad_cast;
         
           CRingFragmentItem(const CRingFragmentItem& rhs);
         
         
  virtual ~CRingFragmentItem();
         
           CRingFragmentItem& operator=(const CRingFragmentItem& rhs);
         
           const int operator==(const CRingFragmentItem& rhs);
         
           const int operator!=(const CRingFragmentItem& rhs);
         
         // accessors.
         
          const uint64_t timestamp();
        
          const uint32_t source();
        
          const size_t payloadSize();
        
          const const void* payloadPointer();
        
          const uint32_t barrierType();
       };

DESCRIPTION

Objects of this class encapsulate a EVB_FRAGMENT ring item. These items are intended to be strung together into events by an event builder. Placing them in a ring allows for a test point.

Since this class is derived from CRingItem, you can create ring items and then commit them to an existing ring via calls to CRingItem::commitToRing. Similarly calls to CRingItem::getFromRing. allow you to get a ring item and then, when you determine from the item type this is an event fragment, construct a CRingFragmentItem from that item.

For a full description of the methods available, see both CRingItem's manpage, and the METHODS section below.

METHODS

CRingFragmentItem(uint64_t timestamp, uint32_t source, uint32_t payloadSize, const void* pBody, uint32_t barrier = 0);

Construct an event fragment ring item. This constructor is normally used prior to inserting fragment item into a ring buffer via CRingItem::commitToRing.

The parameters are pretty much self explanatory. The default on the barrier parameter is correct for fragments that are not part of barrier synchronization.

The timestamp parameter is the timestamp that will be associated with the fragment. The source parameter identifies the source of the fragment. The payloadSize parameter is the number of bytes of payload data that will be copied into the ring item from pBody. barrier is non-zero for barrier fragments and zero if 'normal' non-barrier fragments.

CRingFragmentItem(const CRingItem& rhs) throws std::bad_cast;

Constructs a fragment ring item from a CRingItem. This is normally used after a call from CRingItem::getFromRing that returned a CRingItem object whose type is EVB_FRAGMENT.

The construction then allows your software to get the values of fields of the fragment ring item via the accessor methods described later in this ssection.

CRingFragmentItem(const CRingFragmentItem& rhs);

Copy constructor for ring fragment items. If you find yourself doing a lot of copy construction, you should re-think your code and possibly have CRingFragmentItem objects passed by pointer or reference to your functions/methods.

virtual ~CRingFragmentItem();

Destroys a CRingFragmentItem and frees any dynamic storage that's associated with it.

CRingFragmentItem& operator=(const CRingFragmentItem& rhs);

Assigns the rhs to *this. Any dynamic storage associated with this prior to the assignment is disposed of and it is possible that additional dynamic storage will be allocated to satisfy the needs of the assignment.

const int operator==(const CRingFragmentItem& rhs);

Tests for equality. The payload is not included in the test. If the timestamp, event source barrier type and payload size are equal the ring items are assumed to be equal. This is because there are real problems with an experimental setup that allows more than one fragment to have the same timestamp (except for barriers and non timestamped other items).

const int operator!=(const CRingFragmentItem& rhs);

Returns true if operator== returns false and vica versa.

const uint64_t timestamp();

Accessor method that returns the value of the item's timestamp.

const uint32_t source();

Accessor method that returns the value of the item's source id.

const size_t payloadSize();

Accessor mehthod that returns the size of the item's payload. Using this and payloadPointer allows complete access to the object's payload.

const const void* payloadPointer();

Accessor method that returns a pointer to the item's payload. With this method and payloadSize you can access the contents of the payload.

const uint32_t barrierType();

Accessor method that returns the barrier type field of the item.

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