Event data buffers

Event data buffers

Event data buffers contain the physics data read from the detector systems. The format of these buffers is largely determined by the readout software you write. This section gives an overview of what you may see, however.

• The entity count is equal to the number of events in the buffer.
• Events will never span buffer boundaries in this version.

If you use packets, the general structure of an event is shown below.

The idiom below is an example of how to skip an unrecognized packet type. Bool_t KnownPacket() assumed to return true if the packet type is one you know how to deal with or want to deal with. The pointer pEvent is assumed to be an unsigned short* and points to the beginning of a packet (packet word count) on entry to this fragment:

      ...
      if(!KnownPacket(pEvent)) {
         pEvent += *pEvent;    // Skip the packet.
      }
      else {
         // Handle the packet.
         
         ...
      }
   

Event data buffers