NSCL DAQ Software Documentation
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CRingTextItem

Name

CRingTextItem -- Encapsulate ring items that are lists of text strings.

Synopsis


#include <CRingTextItem>
         

            CRingTextItem
            
  CRingTextItem(uint16_t type, std::vector<std::string> theStrings);
              CRingTextItem(uint16_t type, std::vector<std::string> theStrings, uint32_t offsetTime, time_t timestamp);
            
            
              CRingTextItem(uint16_t type, uint64_t eventTimestamp, uint32_t source, uint32_t  barrier, std::vector<std::string> theStrings, uint32_t  offsetTime, time_t  timestamp, int offsetDivisor = 1);
            
            
              CRingTextItem(const CRingItem& rhs)
          throws std::bad_cast;
              CRingTextItem(const CRingTextItem& rhs);
            
  virtual ~CRingTextItem();
            
  CRingTextItem& operator=(const CRingTextItem& rhs);
              const int operator==(const CRingTextItem& rhs);
              const int operator!=(const CRingTextItem& rhs);
              const std::vector<std::string> getStrings();
              void setTimeOffset(uint32_t offset);
              const uint32_t getTimeOffset();
              const float computeElapsedTime();
              const uint32_t getTimeDivisor();
              void setTimestamp(time_t stamp);
              const time_t getTimestamp();
              const uint32_t getOriginalSourceId();
   // Since V12.0
            
              virtual const std::string typeName();
              virtual const std::string toString();

Description

Text string items contain lists of null terminated documentation strings. These are stored in ring buffers in structures of the type: TextItem. These items have a type code of PACKET_TYPES or MONITORED_VARIABLES. These items are used to document the set of packets you can expect to see in a PHYSICS_EVENT and provide the value of monitored process variables respectively.

Public member functions

CRingTextItem(uint16_t type, std::vector<std::string> theStrings);

Constructs a ring text item of the type specified by type. The text strings will be filled in with the values of the individual strings in theStrings.

The run offset time will be initialized to zero, and the absolute timestamp to the construction time of the object.

CRingTextItem(uint16_t type, std::vector<std::string> theStrings, uint32_t offsetTime, time_t timestamp);

Constructs a text item in a fully specified way. In addition to type and theStrings providing the item type and the strings for the item respectively, offsetTime, and timestamp provide the run time offset and absolute timestamp values respectively.

CRingTextItem(uint16_t type, uint64_t eventTimestamp, uint32_t source, uint32_t barrier, std::vector<std::string> theStrings, uint32_t offsetTime, time_t timestamp, int offsetDivisor = 1);

Constructs a text item with a full body header. The contents of the header are determined by the values of eventTimestamp source and barrier. The offsetDivisor parameter is optional and defaults to 1. It represents the granularity of the offsetTime in seconds. To get the actual time into the run in seconds compute: (float)offsetTime/offsetDivisor.

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

Constructs a text item from a reference to an existing ring item; rhs. If the ring item is not of an appropriate type for a text item, a std::bad_cast exception is thrown.

CRingTextItem(const CRingTextItem& rhs);

Constructs a functional copy of of an existing text ring item; rhs.

CRingTextItem& operator=(const CRingTextItem& rhs);

Provides for assignment between ring text items. When done, the object that is acted on will be a functional copy of the rhs object.

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

Provides for comparison for functional equivalence between two ring text items. The item is compared with rhs. The comparison returns non zero if there is functional equivalence.

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

Returns the logical inverse of operator==.

const std::vector<std::string> getStrings();

Returns the strings in the string list as a vector of strings.

void setTimeOffset(uint32_t offset);

Sets the time offset at which the item was created to offset.

const uint32_t getTimeOffset();

Returns the most recently set time offset for the item.

const float computeElapsedTime();

Since NSCLDAQ-V11.0, elapsed run time is represented in arbitrary ticks. A time divisor is then provided which, in a floating point division of an elapsed run time produces the elapsed time in seconds.

The convenience method computeElapsedTime peforms that computation and returns the elapsed run time in seconds.

const uint32_t getTimeDivisor();

Returns the timing divisor that is used to convert elapsed run times to seconds.

void setTimestamp(time_t stamp);

Sets an absolute timestamp for the item.

const time_t getTimestamp();

Returns the item's absolute timestamp.

uint32_t getOriginalSourceId();

This method was added in NSCLDAQ-12.0. In environments that use the NSCLDAQ event builder, each event source is identified with a unique source id. An event builder, itself, can be used as a data source in a multi-level event builder. This means that event builders can rewrite the body headers of items they otherwise emit unmodified.

Since the original source id is a unique identification of where the data in this ring item comes from, beginning with NSCLDAQ-12.0, the source id supplied at constrution time is also stored in the ring item body itself. This method returns that source id and should be used to identify the source of this data.

virtual const std::string typeName();

Returns a text string that describes the item type. For example if the ring item type is PACKET_TYPES the string Packet types: is returned.

virtual const std::string toString();

Returns a string that is a human readable dump of the ring item. This incluces a list of the strings in the item.

Exceptions

Construction from a ring item can throw a std::bad_cast exception if the underlying ring item is not either a PACKET_TYPES or MONITORED_VARIABLES item.

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