This product is made available subject to acceptance of the EPICS open source license.
pvDataCPP is a computer software package for the efficient
storage, access, and communication, of structured data. It is specifically the
C++ implementation of pvData, which is one part of the set of related products in the EPICS
V4 control system programming environment:
relatedDocumentsV4.html
This is the 12-Dec-2012 version of the C++ implementation of pvData.
The text describes software which is a complete implementation of pvData as currently planned by the EPICS V4 Working Group.
The following is a list of unresolved issues for pvDataCPP:
class Structure ... StringArray fieldNames; FieldConstPtrArray fields class PVStructure ... PVFieldPtrArray pvFields;To
class Structure ... StringArrayPtr fieldNames; FieldConstPtrArrayPtr fields class PVStructure ... PVFieldPtrArrayPtr pvFields;If these are changed several methods also change so that raw vectors are never passed as argument or returned from methods.
pvData is one of a set of related projects. It describes and implements the data that the other projects support. Thus it is not useful by itself but understanding pvData is required in order to understand the other projects. The reader should also become familar with projects pvAccess and pvIOC, which are located via the same sourceforge site as this project.
The Java and C++ implementation of pvData implement the same data model but differ in implementation because of the differences between Java and C++.
It is a good idea to read all of pvDataJava.html but read at least the first two chapters:
The material in these two chapters is NOT repeated in this documentation.
Doxygen documentation is available at doxygenDoc
All code in project pvDataCPP appears in namespace:
namespace epics { namespace pvData { // ... }}
pvDataCPP introspection and data objects are designed to be shared. They are made availiable via std::tr1::shared_ptr. In addition arrays are implemented via std::vector. The following naming conventions are used in typedefs:
As an example pvType.h includes the following definitions:
typedef std::vector<double> DoubleArray; typedef std::tr1::shared_ptr<DoubleArray> DoubleArrayPtr; inline double * get(DoubleArray &value) { return &value[0]; } inline const double * get(const DoubleArray &value) { return static_cast<const double *>(&value[0]); } typedef std::vector<double>::iterator DoubleArray_iterator; typedef std::vector<double>::const_iterator DoubleArray_const_iterator;
where
Directory pvDataApp/pv has header files that completely describe pvData. The implementation is provided in directory pvDataApp/factory. Test programs appears in testApp/pv.
NOTES:
A PVStructure is a field that contains an array of subfields. Each field has code for accessing the field. The interface for each field is an interface that extends PVField. Each field also has an introspection interface, which an extension of Field. This section describes the complete set of C++ introspection and data interfaces for pvData.
Class FieldCreate creates introspection objects. Class PVDataCreate creates data objects. Class Convert provides a rich set of methods for converting and copying data between fields.
Directory pvDataApp/pv has the following header files:
This provides C/C++ definitions for the pvData primitive types: boolean, byte, short, int, long, ubyte,ushort, uint,u long,float, double, and string. Because pvData is network data, the C++ implementation must implement the proper semantics for the primitive types.
pvType.h provides the proper semantics.
It has the definitions:
typedef uint8_t boolean; typedef int8_t int8; typedef int16_t int16; typedef int32_t int32; typedef int64_t int64; typedef uint8_t uint8; typedef uint16_t uint16; typedef uint32_t uint32; typedef uint64_t uint64; // float and double are types typedef std::string String; /** * A boolean array. */ typedef std::vector<uint8> BooleanArray; typedef std::tr1::shared_ptr<BooleanArray> BooleanArrayPtr; /* get is same is ubyte*/ typedef std::vector<uint8>::iterator BooleanArray_iterator; typedef std::vector<uint8>::const_iterator BooleanArray_const_iterator; /** * A byte array. */ typedef std::vector<int8> ByteArray; typedef std::tr1::shared_ptr<ByteArray> ByteArrayPtr; inline int8 * get(ByteArray &value); inline int8 const * get(ByteArray const &value); inline int8 * get(ByteArrayPtr &value); inline int8 const * get(ByteArrayPtr const &value); inline ByteArray & getVector(ByteArrayPtr &value); inline ByteArray const & getVector(ByteArrayPtr const &value); typedef std::vector<int8>::iterator ByteArray_iterator; typedef std::vector<int8>::const_iterator ByteArray_const_iterator; /* similar definitions are present for ALL the primitive types */
where
This subsection describes pvIntrospect.h This file is quite big so rather than showing the entire file, it will be described in parts.
A primary reason for pvData is to support network access to structured data. pvAccess transports top level pvStructures. In addition a pvAccess server holds a set of pvnames, where each pvname if a unique name in the local network.
Given a pvname PV), it is possible to introspect the field without requiring access to data. The reflection and data interfaces are separate because the data may not be available. For example when a pvAccess client connects to a PV, the client library can obtain the reflection information without obtaining any data. Only when a client issues an I/O request will data be available. This separation is especially important for arrays and structures so that a client can discover the type without requiring that a large data array or structure be transported over the network.
Types are defined as:
enum Type { scalar, scalarArray, structure, structureArray; }; class TypeFunc { public: const char* name(Type); static void toString(StringBuilder buf,const Type type); }; enum ScalarType { pvBoolean, pvByte, pvShort, pvInt, pvLong, pvUByte, pvUShort, pvUInt, pvULong, pvFloat,pvDouble, pvString; }; namespace ScalarTypeFunc { public: bool isInteger(ScalarType type); bool isUInteger(ScalarType type); bool isNumeric(ScalarType type); bool isPrimitive(ScalarType type); ScalarType getScalarType(String const &value); const char* name(ScalarType); void toString(StringBuilder buf,ScalarType scalarType); };
Type is one of the following:
ScalarType is one of the following:
TypeFunction is a set of convenience methods for Type
ScalarTypeFunction is a set of convenience methods for ScalarType
This section describes the reflection interfaces which provide the following:
class Field; class Scalar; class ScalarArray; class Structure; class StructureArray; typedef std::tr1::shared_ptr<const Field> FieldConstPtr; typedef std::vector<FieldConstPtr> FieldConstPtrArray; typedef std::tr1::shared_ptr<const Scalar> ScalarConstPtr; typedef std::tr1::shared_ptr<const ScalarArray> ScalarArrayConstPtr; typedef std::tr1::shared_ptr<const Structure> StructureConstPtr; typedef std::tr1::shared_ptr<const StructureArray> StructureArrayConstPtr; class Field : virtual public Serializable, public std::tr1::enable_shared_from_this<Field> { public: POINTER_DEFINITIONS(Field); virtual ~Field(); Type getType() const{return m_type;} virtual String getID() const = 0; virtual void toString(StringBuilder buf) const{toString(buf,0);} virtual void toString(StringBuilder buf,int indentLevel) const; ... }; class Scalar : public Field{ public: POINTER_DEFINITIONS(Scalar); virtual ~Scalar(); typedef Scalar& reference; typedef const Scalar& const_reference; ScalarType getScalarType() const {return scalarType;} virtual void toString(StringBuilder buf) const{toString(buf,0);} virtual void toString(StringBuilder buf,int indentLevel) const; virtual String getID() const; virtual void serialize(ByteBuffer *buffer, SerializableControl *control) const; virtual void deserialize(ByteBuffer *buffer, DeserializableContol *control); ... }; class ScalarArray : public Field{ public: POINTER_DEFINITIONS(ScalarArray); typedef ScalarArray& reference; typedef const ScalarArray& const_reference; ScalarArray(ScalarType scalarType); ScalarType getElementType() const {return elementType;} virtual void toString(StringBuilder buf) const{toString(buf,0);} virtual void toString(StringBuilder buf,int indentLevel) const; virtual String getID() const; virtual void serialize(ByteBuffer *buffer, SerializableControl *control) const; virtual void deserialize(ByteBuffer *buffer, DeserializableControl *control); ... }; class StructureArray : public Field{ public: POINTER_DEFINITIONS(StructureArray); typedef StructureArray& reference; typedef const StructureArray& const_reference; StructureConstPtr getStructure() const {return pstructure;} virtual void toString(StringBuilder buf,int indentLevel=0) const; virtual String getID() const; virtual void serialize(ByteBuffer *buffer, SerializableControl *control) const; virtual void deserialize(ByteBuffer *buffer, DeserializableControl *control); ... }; class Structure : public Field { public: POINTER_DEFINITIONS(Structure); typedef Structure& reference; typedef const Structure& const_reference; std::size_t getNumberFields() const {return numberFields;} FieldConstPtr getField(String const & fieldName) const; FieldConstPtr getField(std::size_t index) const; std::size_t getFieldIndex(String const &fieldName) const; FieldConstPtrArray const & getFields() const {return fields;} StringArray const & getFieldNames() const; void renameField(std::size_t fieldIndex,String const &newName); String getFieldName(std::size_t fieldIndex); virtual void toString(StringBuilder buf,int indentLevel) const; virtual String getID() const; virtual void serialize(ByteBuffer *buffer, SerializableControl *control) const; virtual void deserialize(ByteBuffer *buffer, DeserializableControl *control); ... }; class FieldCreate { public: static FieldCreatePtr getFieldCreate(); ScalarConstPtr createScalar(ScalarType scalarType) const ScalarArrayConstPtr createScalarArray(ScalarType elementType) const; StructureArrayConstPtr createStructureArray(StructureConstPtr const & structure) const; StructureConstPtr createStructure ( StringArray const & fieldNames, FieldConstPtrArray const & fields) const; StructureConstPtr createStructure ( String const &id, StringArray const & fieldNames, FieldConstPtrArray const & fields) const; StructureConstPtr appendField( StructureConstPtr const & structure, String const &fieldName, FieldConstPtr const & field) const; StructureConstPtr appendFields( StructureConstPtr const & structure, StringArray const & fieldNames, FieldConstPtrArray const & fields) const; FieldConstPtr deserialize(ByteBuffer* buffer, DeserializableControl* control) const; ... }; extern FieldCreatePtr getFieldCreate();
The file standardField.h has a class description for creating or sharing Field objects for standard fields. For each type of field a method is provided. Each creates a structure that has a field named "value" and a set of properyt fields, The property field is a comma separated string of property names of the following: alarm, timeStamp, display, control, and valueAlarm. An example is "alarm,timeStamp,valueAlarm". The method with properties creates a structure with fields named value and each of the property names. Each property field is a structure defining the property. The details about each property is given in the section named "Property". For example the call:
StructureConstPtr example = standardField->scalar( pvDouble, "value,alarm,timeStamp");
Will result in a Field definition that has the form:
structure example double value alarm_t alarm int severity int status string message timeStamp_t timeStamp long secondsPastEpoch int nanoSeconds int userTag
In addition there are methods that create each of the property structures, i.e. the methods named: alarm, .... enumeratedAlarm."
standardField.h contains:
class StandardField; typedef std::tr1::shared_ptr<StandardField> StandardFieldPtr; class StandardField { public: static StandardFieldPtr getStandardField(); ~StandardField(); StructureConstPtr scalar(ScalarType type,String const &properties); StructureConstPtr scalarArray( ScalarType elementType, String const &properties); StructureConstPtr structureArray( StructureConstPtr const & structure,String const &properties); StructureConstPtr enumerated(); StructureConstPtr enumerated(String const &properties); StructureConstPtr alarm(); StructureConstPtr timeStamp(); StructureConstPtr display(); StructureConstPtr control(); StructureConstPtr booleanAlarm(); StructureConstPtr byteAlarm(); StructureConstPtr ubyteAlarm(); StructureConstPtr shortAlarm(); StructureConstPtr ushortAlarm(); StructureConstPtr intAlarm(); StructureConstPtr uintAlarm(); StructureConstPtr longAlarm(); StructureConstPtr ulongAlarm(); StructureConstPtr floatAlarm(); StructureConstPtr doubleAlarm(); StructureConstPtr enumeratedAlarm(); ... };
This subsection describes pvData.h This file is quite big so rather than showing the entire file, it will be described in parts.
These are typedefs for Array and Ptr for the various pvData class definitions, i.e. typdefs for "std::vector" and "std::tr1::shared_ptr".
class PVAuxInfo; class PostHandler; class PVField; class PVScalar; class PVScalarArray; class PVStructure; class PVStructureArray; typedef std::tr1::shared_ptr<PVAuxInfo> PVAuxInfoPtr; typedef std::tr1::shared_ptr<PostHandler> PostHandlerPtr; typedef std::tr1::shared_ptr<PVField> PVFieldPtr; typedef std::vector<PVFieldPtr> PVFieldPtrArray; typedef std::vector<PVFieldPtr>::iterator PVFieldPtrArray_iterator; typedef std::vector<PVFieldPtr>::const_iterator PVFieldPtrArray_const__iterator; typedef std::tr1::shared_ptr<PVScalar> PVScalarPtr; typedef std::tr1::shared_ptr<PVScalarArray> PVScalarArrayPtr; typedef std::tr1::shared_ptr<PVStructure> PVStructurePtr; typedef std::vector<PVStructurePtr> PVStructurePtrArray; typedef std::vector<PVStructurePtr>::iterator PVStructurePtrArray_iterator; typedef std::vector<PVStructurePtr>::const_iterator PVStructurePtrArray_const__iterator; typedef std::tr1::shared_ptr<PostHandler> PostHandlerPtr
PostHandler is a class that must be implemented by any code that calls setPostHandler. It's single virtual method. postPut is called whenever PVField::postPut is called.
class PostHandler { public: POINTER_DEFINITIONS(PostHandler); virtual ~PostHandler(){} virtual void postPut() = 0; };
PVField is the base interface for accessing data. A data structure consists of a top level PVStructure. Every field of every structure of every top level structure has a PVField associated with it.
class PVField : virtual public Serializable, public std::tr1::enable_shared_from_this<PVField> { public: POINTER_DEFINITIONS(PVField); virtual ~PVField(); virtual void message(String message,MessageType messageType); String getFieldName() const ; virtual void setRequester(RequesterPtr const &prequester); std::size_t getFieldOffset() const; std::size_t getNextFieldOffset() const; std::size_t getNumberFields() const; PVAuxInfoPtr & getPVAuxInfo() bool isImmutable() const; virtual void setImmutable(); const FieldConstPtr & getField() const ; PVStructure * getParent() const void replacePVField(const PVFieldPtr& newPVField); void renameField(String const &newName); void postPut() ; void setPostHandler(PostHandlerPtr const &postHandler); virtual bool equals(PVField &pv); virtual void toString(StringBuilder buf) ; virtual void toString(StringBuilder buf,int indentLevel); std::ostream& dumpValue(std::ostream& o) const; ... }
The public methods for PVField are:
AuxInfo (Auxillary Information) is information about a field that is application specific. It will not be available outside the application that implements the database. In particular it will not be made available to Channel Access. It is used by the database itself to override the default implementation of fields. The JavaIOC uses it for attaching support code. Database Configuration and other tools can use it for configuration information. Each Field and each PVField can have have an arbitrary number of auxInfos. An auxInfo is a (key,PVScalar) pair where key is a string.
class PVAuxInfo : private NoDefaultMethods { public: typedef std::map<String,PVScalarPtr> PVInfoMap; typedef std::map<String,PVScalarPtr>::iterator PVInfoIter; typedef std::pair<String,PVScalarPtr> PVInfoPair; PVAuxInfo(PVField *pvField); ~PVAuxInfo(); PVField * getPVField(); PVScalarPtr createInfo(String const &key,ScalarType scalarType); PVScalarPtr getInfo(String const &key); PVInfoMap & getInfoMap(); void toString(StringBuilder buf); void toString(StringBuilder buf,int indentLevel); ... };
where
This is the base class for all scalar data.
class PVScalar : public PVField { public: POINTER_DEFINITIONS(PVScalar); virtual ~PVScalar(); typedef PVScalar &reference; typedef const PVScalar& const_reference; const ScalarConstPtr getScalar() const ; ... }
where
The interfaces for primitive data types are:
template<typename T> class PVScalarValue : public PVScalar { public: POINTER_DEFINITIONS(PVScalarValue); typedef T value_type; typedef T* pointer; typedef const T* const_pointer; virtual ~PVScalarValue() {} virtual T get() const = 0; virtual void put(T value) = 0; ... } // PVString is special case, since it implements SerializableArray class PVString : public PVScalarValue<String>, SerializableArray { public: virtual ~PVString() {} ... };
where
PVArray is the base interface for all the other PV Array interfaces. It extends PVField and provides the additional methods:
class PVArray : public PVField, public SerializableArray { public: POINTER_DEFINITIONS(PVArray); virtual ~PVArray(); virtual void setImmutable(); std::size_t getLength() const; virtual void setLength(std::size_t length); std::size_t getCapacity() const; bool isCapacityMutable() const; void setCapacityMutable(bool isMutable); virtual void setCapacity(std::size_t capacity) = 0; ... };
This is the argument to one of the get methods of PVValueArray.
template<typename T> class PVArrayData { private: std::vector<T> init; public: POINTER_DEFINITIONS(PVArrayData); typedef T value_type; typedef T* pointer; typedef const T* const_pointer; std::vector<T> & data; std::size_t offset; PVArrayData() : data(init) {} };
PVScalarArray is the base class for scalar array data. PVValueArray is a templete for the various scalar array data classes. There is a class for each possible scalar type, i. e. PVBooleanArray, ..., PVStringArray.
class PVScalarArray : public PVArray { public: POINTER_DEFINITIONS(PVScalarArray); virtual ~PVScalarArray(); typedef PVScalarArray &reference; typedef const PVScalarArray& const_reference; const ScalarArrayConstPtr getScalarArray() const ; virtual std::ostream& dumpValue(std::ostream& o, size_t index) const = 0; ... }
where
This is a template class plus instances for PVBooleanArray, ..., PVStringArray.
template<typename T> class PVValueArray : public PVScalarArray { public: POINTER_DEFINITIONS(PVValueArray); typedef T value_type; typedef T* pointer; typedef const T* const_pointer; typedef PVArrayData<T> ArrayDataType; typedef std::vector<T> vector; typedef const std::vector<T> const_vector; typedef std::tr1::shared_ptr<vector> shared_vector; typedef PVValueArray & reference; typedef const PVValueArray & const_reference; virtual ~PVValueArray() {} virtual std::size_t get( std::size_t offset, std::size_t length, ArrayDataType &data) = 0; virtual std::size_t put(std::size_t offset, std::size_t length, const_pointer from, std::size_t fromOffset) = 0; virtual std::size_t put(std::size_t offset, std::size_t length, const_vector &from, std::size_t fromOffset); virtual void shareData( shared_vector const & value, std::size_t capacity, std::size_t length) = 0; virtual pointer get() = 0; virtual pointer get() const = 0; virtual vector const & getVector() = 0; virtual shared_vector const & getSharedVector() = 0; std::ostream& dumpValue(std::ostream& o) const; std::ostream& dumpValue(std::ostream& o, size_t index) const; protected: PVValueArray(ScalarArrayConstPtr const & scalar) : PVScalarArray(scalar) {} friend class PVDataCreate; }; template<typename T> std::size_t PVValueArray<T>::put( std::size_t offset, std::size_t length, const_vector &from, std::size_t fromOffset) { return put(offset,length, &from[0], fromOffset); } /** * Definitions for the various scalarArray types. */ typedef PVArrayData<uint8> BooleanArrayData; typedef PVValueArray<uint8> PVBooleanArray; typedef std::tr1::shared_ptr<PVBooleanArray> PVBooleanArrayPtr; typedef PVArrayData<int8> ByteArrayData; typedef PVValueArray<int8> PVByteArray; typedef std::tr1::shared_ptr<PVByteArray> PVByteArrayPtr; typedef PVArrayData<int16> ShortArrayData; typedef PVValueArray<int16> PVShortArray; typedef std::tr1::shared_ptr<PVShortArray> PVShortArrayPtr; typedef PVArrayData<int32> IntArrayData; typedef PVValueArray<int32> PVIntArray; typedef std::tr1::shared_ptr<PVIntArray> PVIntArrayPtr; typedef PVArrayData<int64> LongArrayData; typedef PVValueArray<int64> PVLongArray; typedef std::tr1::shared_ptr<PVLongArray> PVLongArrayPtr; typedef PVArrayData<uint8> UByteArrayData; typedef PVValueArray<uint8> PVUByteArray; typedef std::tr1::shared_ptr<PVUByteArray> PVUByteArrayPtr; typedef PVArrayData<uint16> UShortArrayData; typedef PVValueArray<uint16> PVUShortArray; typedef std::tr1::shared_ptr<PVUShortArray> PVUShortArrayPtr; typedef PVArrayData<uint32> UIntArrayData; typedef PVValueArray<uint32> PVUIntArray; typedef std::tr1::shared_ptr<PVUIntArray> PVUIntArrayPtr; typedef PVArrayData<uint64> ULongArrayData; typedef PVValueArray<uint64> PVULongArray; typedef std::tr1::shared_ptr<PVULongArray> PVULongArrayPtr; typedef PVArrayData<float> FloatArrayData; typedef PVValueArray<float> PVFloatArray; typedef std::tr1::shared_ptr<PVFloatArray> PVFloatArrayPtr; typedef PVArrayData<double> DoubleArrayData; typedef PVValueArray<double> PVDoubleArray; typedef std::tr1::shared_ptr<PVDoubleArray> PVDoubleArrayPtr; typedef PVArrayData<String> StringArrayData; typedef PVValueArray<String> PVStringArray; typedef std::tr1::shared_ptr<PVStringArray> PVStringArrayPtr;
where
Both get and put return the number of elements actually transfered. The arguments are:
The caller must be prepared to make multiple calls to retrieve or put an entire array. A caller should accept or put partial arrays. For example the following reads an entire array:
void getArray(PVDoubleArrayPtr & pv,DoubleArray const & to) { size_t len = pv->getLength(); if(to.size()<len) to.resize(len); DoubleArrayData data; size_t offset = 0; while(offset<len) { size_t num = pv->get(offset,(len-offset),data); DoubleArray &from = data.data; size_t fromOffset = data.offset; for(size_t i=0; i<num; i++) to[i+offset] = from[i + fromOffset]; offset += num; } }
The interface for a structure is:
class PVStructure : public PVField,public BitSetSerializable { public: POINTER_DEFINITIONS(PVStructure); virtual ~PVStructure(); typedef PVStructure & reference; typedef const PVStructure & const_reference; virtual void setImmutable(); StructureConstPtr getStructure() const; const PVFieldPtrArray & getPVFields() const; PVFieldPtr getSubField(String const &fieldName) const; PVFieldPtr getSubField(std::size_t fieldOffset) const; void appendPVField( String const &fieldName, PVFieldPtr const & pvField); void appendPVFields( StringArray const & fieldNames, PVFieldPtrArray const & pvFields); void removePVField(String const &fieldName); PVBooleanPtr getBooleanField(String const &fieldName) ; PVBytePtr getByteField(String const &fieldName) ; PVShortPtr getShortField(String const &fieldName) ; PVIntPtr getIntField(String const &fieldName) ; PVLongPtr getLongField(String const &fieldName) ; PVUBytePtr getUByteField(String const &fieldName) ; PVUShortPtr getUShortField(String const &fieldName) ; PVUIntPtr getUIntField(String const &fieldName) ; PVULongPtr getULongField(String const &fieldName) ; PVFloatPtr getFloatField(String const &fieldName) ; PVDoublePtr getDoubleField(String const &fieldName) ; PVStringPtr getStringField(String const &fieldName) ; PVStructurePtr getStructureField(String const &fieldName) ; PVScalarArrayPtr getScalarArrayField( String const &fieldName,ScalarType elementType) ; PVStructureArrayPtr getStructureArrayField(String const &fieldName) ; String getExtendsStructureName() const; bool putExtendsStructureName( String const &extendsStructureName); virtual void serialize( ByteBuffer *pbuffer,SerializableControl *pflusher) const ; virtual void deserialize( ByteBuffer *pbuffer,DeserializableControl *pflusher); virtual void serialize(ByteBuffer *pbuffer, SerializableControl *pflusher,BitSet *pbitSet) const; virtual void deserialize(ByteBuffer *pbuffer, DeserializableControl*pflusher,BitSet *pbitSet); PVStructure(StructureConstPtr const & structure); PVStructure(StructureConstPtr const & structure,PVFieldPtrArray const & pvFields); };
where
The interface for an array of structures is:
typedef PVArrayData<PVStructurePtr> StructureArrayData; class PVStructureArray : public PVArray { public: POINTER_DEFINITIONS(PVStructureArray); typedef PVStructurePtr value_type; typedef PVStructurePtr* pointer; typedef const PVStructurePtr* const_pointer; typedef PVArrayData<PVStructurePtr> ArrayDataType; typedef std::vector<PVStructurePtr> vector; typedef const std::vector<PVStructurePtr> const_vector; typedef std::tr1::shared_ptr<vector> shared_vector; typedef PVStructureArray &reference; typedef const PVStructureArray& const_reference; virtual ~PVStructureArray() {} virtual void setCapacity(size_t capacity); virtual void setLength(std::size_t length); virtual StructureArrayConstPtr getStructureArray() const ; virtual std::size_t append(std::size_t number); virtual bool remove(std::size_t offset,std::size_t number); virtual void compress(); virtual std::size_t get(std::size_t offset, std::size_t length, StructureArrayData &data); virtual std::size_t put(std::size_t offset,std::size_t length, const_vector const & from, std::size_t fromOffset); virtual void shareData( shared_vector const & value, std::size_t capacity, std::size_t length); virtual void serialize(ByteBuffer *pbuffer, SerializableControl *pflusher) const; virtual void deserialize(ByteBuffer *buffer, DeserializableControl *pflusher); virtual void serialize(ByteBuffer *pbuffer, SerializableControl *pflusher, std::size_t offset, std::size_t count) const ; virtual pointer get() { return &((*value.get())[0]); } virtual pointer get() const { return &((*value.get())[0]); } virtual vector const & getVector() {return *value;} virtual shared_vector const & getSharedVector() {return value;} ... }
where
The other methods are similar to the methods for other array types.
PVDataCreate is an interface that provides methods that create PVField interfaces. A factory is provided that creates PVDataCreate.
class PVDataCreate { public: static PVDataCreatePtr getPVDataCreate(); PVFieldPtr createPVField(FieldConstPtr const & field); PVFieldPtr createPVField(PVFieldPtr const & fieldToClone); PVScalarPtr createPVScalar(ScalarConstPtr const & scalar); PVScalarPtr createPVScalar(ScalarType scalarType); PVScalarPtr createPVScalar(PVScalarPtr const & scalarToClone); PVScalarArrayPtr createPVScalarArray(ScalarArrayConstPtr const & scalarArray); PVScalarArrayPtr createPVScalarArray(ScalarType elementType); PVScalarArrayPtr createPVScalarArray(PVScalarArrayPtr const & scalarArrayToClone); PVStructureArrayPtr createPVStructureArray(StructureArrayConstPtr const & structureArray); PVStructurePtr createPVStructure(StructureConstPtr const & structure); PVStructurePtr createPVStructure( StringArray const & fieldNames,PVFieldPtrArray const & pvFields); PVStructurePtr createPVStructure(PVStructurePtr const & structToClone); ... }; extern PVDataCreatePtr getPVDataCreate();
where
A class StandardPVField has methods for creating standard data fields. Like class StandardField it has two forms of the methods which create a field, one without properties and one with properties. Again the properties is some combination of alarm, timeStamp, control, display, and valueAlarm. And just like StandardField there are methods to create the standard properties. The methods are:
class StandardPVField; typedef std::tr1::shared_ptr<StandardPVField> StandardPVFieldPtr; class StandardPVField : private NoDefaultMethods { public: static StandardPVFieldPtr getStandardPVField(); ~StandardPVField(); PVStructurePtr scalar(ScalarType type,String const &properties); PVStructurePtr scalarArray(ScalarType elementType, String const &properties); PVStructurePtr structureArray(StructureConstPtr const &structure,String const &properties); PVStructurePtr enumerated(StringArray const &choices); PVStructurePtr enumerated(StringArray const &choices, String const &properties); ... } extern StandardPVFieldPtr getStandardPVField();
NOTE about copying immutable array fields. If an entire immutable array field is copied to another array that has the same elementType, both offsets are 0, and the length is the length of the source array, then the shareData method of the target array is called and the target array is set immutable. Thus the source and target share the same primitive array.
This section describes the supported conversions between data types.
bool operator==(PVField&, PVField&); static inline bool operator!=(PVField& a, PVField& b) {return !(a==b);} bool operator==(const Field&, const Field&); bool operator==(const Scalar&, const Scalar&); bool operator==(const ScalarArray&, const ScalarArray&); bool operator==(const Structure&, const Structure&); bool operator==(const StructureArray&, const StructureArray&); static inline bool operator!=(const Field& a, const Field& b) {return !(a==b);} static inline bool operator!=(const Scalar& a, const Scalar& b) {return !(a==b);} static inline bool operator!=(const ScalarArray& a, const ScalarArray& b) {return !(a==b);} static inline bool operator!=(const Structure& a, const Structure& b) {return !(a==b);} static inline bool operator!=(const StructureArray& a, const StructureArray& b) {return !(a==b);} class Convert; typedef std::tr1::shared_ptr<Convert> ConvertPtr; class Convert { public: static ConvertPtr getConvert(); ~Convert(); void getFullName(StringBuilder buf,PVFieldPtr const & pvField); bool equals(PVFieldPtr const &a,PVFieldPtr const &b); bool equals(PVField &a,PVField &b); void getString(StringBuilder buf,PVFieldPtr const & pvField,int indentLevel); void getString(StringBuilder buf,PVFieldPtr const & pvField); void getString(StringBuilder buf,PVField const * pvField,int indentLevel); void getString(StringBuilder buf,PVField const * pvField); std::size_t fromString( PVStructurePtr const &pv, StringArray const & from, std::size_t fromStartIndex = 0); void fromString(PVScalarPtr const & pv, String const & from); std::size_t fromString(PVScalarArrayPtr const & pv, String const &from); std::size_t fromStringArray( PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, StringArray const & from, std::size_t fromOffset); std::size_t toStringArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, StringArray & to, std::size_t toOffset); bool isCopyCompatible(FieldConstPtr const & from, FieldConstPtr const & to); void copy(PVFieldPtr const & from, PVFieldPtr const & to); bool isCopyScalarCompatible( ScalarConstPtr const & from, ScalarConstPtr const & to); void copyScalar(PVScalarPtr const & from, PVScalarPtr const & to); bool isCopyScalarArrayCompatible( ScalarArrayConstPtr const & from, ScalarArrayConstPtr const & to); std::size_t copyScalarArray( PVScalarArrayPtr const & from, std::size_t offset, PVScalarArrayPtr const & to, std::size_t toOffset, std::size_t length); bool isCopyStructureCompatible( StructureConstPtr const & from, StructureConstPtr const & to); void copyStructure(PVStructurePtr const & from, PVStructurePtr const & to); bool isCopyStructureArrayCompatible( StructureArrayConstPtr const & from, StructureArrayConstPtr const & to); void copyStructureArray( PVStructureArrayPtr const & from, PVStructureArrayPtr const & to); int8 toByte(PVScalarPtr const & pv); int16 toShort(PVScalarPtr const & pv); int32 toInt(PVScalarPtr const & pv); int64 toLong(PVScalarPtr const & pv); uint8 toUByte(PVScalarPtr const & pv); uint16 toUShort(PVScalarPtr const & pv); uint32 toUInt(PVScalarPtr const & pv); uint64 toULong(PVScalarPtr const & pv); float toFloat(PVScalarPtr const & pv); double toDouble(PVScalarPtr const & pv); String toString(PVScalarPtr const & pv); void fromByte(PVScalarPtr const & pv,int8 from); void fromShort(PVScalarPtr const & pv,int16 from); void fromInt(PVScalarPtr const & pv, int32 from); void fromLong(PVScalarPtr const & pv, int64 from); void fromUByte(PVScalarPtr const & pv,uint8 from); void fromUShort(PVScalarPtr const & pv,uint16 from); void fromUInt(PVScalarPtr const & pv, uint32 from); void fromULong(PVScalarPtr const & pv, uint64 from); void fromFloat(PVScalarPtr const & pv, float from); void fromDouble(PVScalarPtr const & pv, double from); std::size_t toByteArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, int8* to, std::size_t toOffset); std::size_t toShortArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, int16* to, std::size_t toOffset); std::size_t toIntArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, int32* to, std::size_t toOffset); std::size_t toLongArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, int64* to, std::size_t toOffset); std::size_t toUByteArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, uint8* to, std::size_t toOffset); std::size_t toUShortArray(PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, uint16* to, std::size_t toOffset); std::size_t toUIntArray( PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, uint32* to, std::size_t toOffset); std::size_t toULongArray( PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, uint64* to, std::size_t toOffset); std::size_t toFloatArray( PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, float* to, std::size_t toOffset); std::size_t toDoubleArray( PVScalarArrayPtr const & pv, std::size_t offset, std::size_t length, double* to, std::size_t toOffset); std::size_t fromByteArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const int8* from, std::size_t fromOffset); std::size_t fromByteArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const ByteArray & from, std::size_t fromOffset); std::size_t fromShortArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const int16* from, std::size_t fromOffset); std::size_t fromShortArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const ShortArray & from, std::size_t fromOffset); std::size_t fromIntArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const int32* from, std::size_t fromOffset); std::size_t fromIntArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const IntArray & from, std::size_t fromOffset); std::size_t fromLongArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const int64* from, std::size_t fromOffset); std::size_t fromLongArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const LongArray & from, std::size_t fromOffset); std::size_t fromUByteArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const uint8* from, std::size_t fromOffset); std::size_t fromUByteArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const UByteArray & from, std::size_t fromOffset); std::size_t fromUShortArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const uint16* from, std::size_t fromOffset); std::size_t fromUShortArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const UShortArray & from, std::size_t fromOffset); std::size_t fromUIntArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const uint32* from, std::size_t fromOffset); std::size_t fromUIntArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const UIntArray & from, std::size_t fromOffset); std::size_t fromULongArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const uint64* from, std::size_t fromOffset); std::size_t fromULongArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const ULongArray & from, std::size_t fromOffset); std::size_t fromFloatArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const float* from, std::size_t fromOffset); std::size_t fromFloatArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const FloatArray & from, std::size_t fromOffset); std::size_t fromDoubleArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const double* from, std::size_t fromOffset); std::size_t fromDoubleArray( PVScalarArrayPtr & pv, std::size_t offset, std::size_t length, const DoubleArray & from, std::size_t fromOffset); void newLine(StringBuilder buf, int indentLevel); ... } extern ConvertPtr getConvert();
The array methods all return the number of elements copied or converted. This can be less than len if the PVField array contains less than len elements.
newLine is a convenience method for code that implements toString It generates a newline and inserts blanks at the beginning of the newline.
Only fields named "value" have properties. A record can have multiple value fields, which can appear in the top level structure of a record or in a substructure. All other fields in the structure containing a value field are considered properties of the value field. The fieldname is also the property name. The value field can have any type, i.e. scalar, scalarArray, or structure. Typical property fields are timeStamp, alarm, display, control, and history. The timeStamp is a special case. If it appears anywhere in the structure hieraracy above a value field it is a property of the value field.
For example the following top level structure has a single value field. The value field has properties alarm, timeStamp, and display.
structure counterOutput double value alarm_t int severity 0 int status 0 string message timeStamp_t long secondsPastEpoch int nanoSeconds int userTag display_t double limitLow 0.0 double limitHigh 10.0 string description "Sample Description" string format "%f" string units volts
The following example has three value fields each with properties alarm and timeStamp. Voltage, Current, and Power each have a different alarms but all share the timeStamp.
structure powerSupplyValue double value alarm_t int severity 0 int status 0 string message structure powerSupplySimple alarm_t int severity 0 int status 0 string message timeStamp_t long secondsPastEpoch int nanoSeconds int userTag powerSupplyValue_t voltage double value alarm_t int severity 0 int status 0 string message powerSupplyValue_t power double value alarm_t int severity 0 int status 0 string message powerSupplyValue_t current double value alarm_t int severity 0 int status 0 string message
The following field names have special meaning, i.e. support properties for general purpose clients.
In addition a structure can have additional fields that support the value field but are not recognized by most general purpose client tools. Typical examples are:
The model allows for device records. A device record has structure fields that that support the PVData data model. For example a powerSupport record can have fields power, voltage, current that each support the PVData data model.
Except for enumerated, each property has two files: a property.h and a pvProperty.h . For example: timeStamp.h and pvTimeStamp.h In each case the property.h file defined methods for manipulating the property data and the pvProperty.h provides methods to transfer the property data to/from a pvData structure.
All methods copy data via copy by value semantics, i.e. not by pointer or by reference. No property class calls new or delete and all allow the compiler to generate default methods. All allow a class instance to be generated on the stack. For example the following is permitted:
void example(PVFieldPtr const &pvField) { Alarm alarm; PVAlarm pvAlarm; bool result; result = pvAlarm.attach(pvField); assert(result); Alarm al; al.setMessage(String("testMessage")); al.setSeverity(majorAlarm); result = pvAlarm.set(al); assert(result); alarm = pvAlarm.get(); ... }
A timeStamp is represented by the following structure
structure timeStamp long secondsPartEpoch int nanoSeconds int userTag
The Epoch is the posix epoch, i.e. Jan 1, 1970 00:00:00 UTC. Both the seconds and nanoSeconds are signed integers and thus can be negative. Since the seconds is kept as a 64 bit integer, it allows for a time much greater than the present age of the universe. Since the nanoSeconds portion is kept as a 32 bit integer it is subject to overflow if a value that corresponds to a value that is greater than a little more than 2 seconds of less that about -2 seconds. The support code always adjust seconds so that the nanoSecconds part is normlized, i. e. it has is 0<=nanoSeconds<nanoSecPerSec..
Two header files are provided for manipulating time stamps:
This provides
extern int32 milliSecPerSec; extern int32 microSecPerSec; extern int32 nanoSecPerSec; extern int64 posixEpochAtEpicsEpoch; class TimeStamp { public: TimeStamp() :secondsPastEpoch(0), nanoSeconds(0), userTag(0) {} TimeStamp(int64 secondsPastEpoch,int32 nanoSeconds = 0,int32 userTag = 0); //default constructors and destructor are OK //This class should not be extended void normalize(); void fromTime_t(const time_t &); void toTime_t(time_t &) const; int64 getSecondsPastEpoch() const {return secondsPastEpoch;} int64 getEpicsSecondsPastEpoch() const { return secondsPastEpoch - posixEpochAtEpicsEpoch; } int32 getNanoSeconds() const {return nanoSeconds;} int32 getUserTag() const {return userTag;} void setUserTag(int userTag) {this->userTag = userTag;} void put(int64 secondsPastEpoch,int32 nanoSeconds = 0) { this->secondsPastEpoch = secondsPastEpoch; this->nanoSeconds = nanoSeconds; normalize(); } void put(int64 milliseconds); void getCurrent(); double toSeconds() const ; bool operator==(TimeStamp const &) const; bool operator!=(TimeStamp const &) const; bool operator<=(TimeStamp const &) const; bool operator< (TimeStamp const &) const; bool operator>=(TimeStamp const &) const; bool operator> (TimeStamp const &) const; static double diff(TimeStamp const & a,TimeStamp const & b); TimeStamp & operator+=(int64 seconds); TimeStamp & operator-=(int64 seconds); TimeStamp & operator+=(double seconds); TimeStamp & operator-=(double seconds); int64 getMilliseconds(); // milliseconds since epoch ... }
where
The TimeStamp class provides arithmetic operations on time stamps. The result is always kept in normalized form, which means that the nano second portion is 0≤=nano<nanoSecPerSec. Note that it is OK to have timeStamps for times previous to the epoch.
TimeStamp acts like a primitive. It can be allocated on the stack and the compiler is free to generate default methods, i.e. copy constructor, assignment constructor, and destructor.
One use for TimeStamp is to time how long a section of code takes to execute. This is done as follows:
TimeStamp startTime; TimeStamp endTime; ... startTime.getCurrent(); // code to be measured for elapsed time endTime.getCurrent(); double time = TimeStamp::diff(endTime,startTime);
class PVTimeStamp { public: PVTimeStamp(); //default constructors and destructor are OK //This class should not be extended //returns (false,true) if pvField(isNot, is valid timeStamp structure bool attach(PVFieldPtr const &pvField); void detach(); bool isAttached(); // following throw logic_error if not attached to PVField // a set returns false if field is immutable void get(TimeStamp &) const; bool set(TimeStamp const & timeStamp); };
where
An alarm structure is defined as follows:
structure alarm int severity int status string message
Note that neither severity or status is defined as an enumerated structure. The reason is performance, i. e. prevent passing the array of choice strings everywhere. The file alarm.h provides the choice strings. Thus all code that needs to know about alarms share the exact same choice strings.
Two header files are provided for manipulating alarms:
enum AlarmSeverity { noAlarm,minorAlarm,majorAlarm,invalidAlarm,undefinedAlarm }; enum AlarmStatus { noStatus,deviceStatus,driverStatus,recordStatus, dbStatus,confStatus,undefinedStatus,clientStatus }; class AlarmSeverityFunc { public: static AlarmSeverity getSeverity(int value); static StringArrayPtr getSeverityNames(); }; class AlarmStatusFunc { public: static AlarmStatus getStatus(int value); static StringArrayPtr getStatusNames(); }; class Alarm { public: Alarm(); //default constructors and destructor are OK String getMessage(); void setMessage(String const &value); AlarmSeverity getSeverity() const; void setSeverity(AlarmSeverity value); AlarmStatus getStatus() const; void setStatus(AlarmStatus value); };
Alarm Severity defines the possible alarm severities:
Alarm Status defines the possible choices for alarm status:
Alarm has the methods:
class PVAlarm { public: PVAlarm() : pvSeverity(0),pvMessage(0) {} //default constructors and destructor are OK //returns (false,true) if pvField(isNot, is valid enumerated structure //An automatic detach is issued if already attached. bool attach(PVFieldPtr const &pvField); void detach(); bool isAttached(); // each of the following throws logic_error is not attached to PVField // set returns false if field is immutable void get(Alarm & alarm) const; bool set(Alarm const & alarm); };
where
Control information is represented by the following structure
structure control double limitLow double limitHigh double minStep
Two header files are provided for manipulating control:
class Control { public: Control(); //default constructors and destructor are OK double getLow() const; double getHigh() const; double getMinStep() const; void setLow(double value); void setHigh(double value); void setMinStep(double value); };
where
class PVControl { public: PVControl(); //default constructors and destructor are OK //returns (false,true) if pvField(isNot, is valid enumerated structure //An automatic detach is issued if already attached. bool attach(PVFieldPtr const &pvField); void detach(); bool isAttached(); // each of the following throws logic_error is not attached to PVField // set returns false if field is immutable void get(Control &) const; bool set(Control const & control); };
where
Display information is represented by the following structure
structure display double limitLow double limitHigh string description string format string units
Two header files are provided for manipulating display:
class Display { public: Display(); //default constructors and destructor are OK double getLow() const; double getHigh() const; void setLow(double value); void setHigh(double value); String getDescription() const; void setDescription(String const &value); String getFormat() const; void setFormat(String const &value); String getUnits() const; void setUnits(String const &value); };
where
class PVDisplay { public: PVDisplay() : pvDescription(0),pvFormat(),pvUnits(),pvLow(),pvHigh() {} //default constructors and destructor are OK //An automatic detach is issued if already attached. bool attach(PVFieldPtr const&pvField); void detach(); bool isAttached(); // each of the following throws logic_error is not attached to PVField // a set returns false if field is immutable void get(Display &) const; bool set(Display const & display); };
where
An enumerated structure is a structure that has fields:
structure int index string[] choices
For enumerated structures a single header file pvEnumerted.h is available
class PVEnumerated { public: PVEnumerated(); //default constructors and destructor are OK //This class should not be extended //returns (false,true) if pvField(isNot, is valid enumerated structure //An automatic detach is issued if already attached. bool attach(PVFieldPtr const &pvField); void detach(); bool isAttached(); // each of the following throws logic_error is not attached to PVField // a set returns false if field is immutable bool setIndex(int32 index); int32 getIndex(); String getChoice(); bool choicesMutable(); StringArrayPtr const & getChoices(); int32 getNumberChoices(); bool setChoices(StringArray &choices,int32 numberChoices); };
where
Assume that code wants to print two fields from a PVStructure:
The following code uses introspection to get the desired information.
void getValueAndTimeStamp(PVStructurePtr pvStructure,StringBuilder buf) { PVFieldPtr valuePV = pvStructure->getSubField(String("value")); if(valuePV.get()==NULL) { buf += "value field not found"; return; } buf += "value "; valuePV->toString(&buf); PVFieldPtr timeStampPV = pvStructure->getSubField(String("timeStamp")); if(timeStampPV.get()==NULL) { buf += "timeStamp field not found"; return; } buf += " timeStamp "; timeStampPV->toString(&buf); }
Example of creating a scalar field.
PVDataCreatePtr pvDataCreate = getPVDataCreate(); PVDoublePtr pvValue = static_pointer_cast<PVDouble>( pvDataCreate->createPVScalar(pvDouble));
Create a structure with a value and an alarm the hard way
FieldCreatePtr fieldCreate = getFieldCreate(); PVDataCreatePtr pvDataCreate = getPVDataCreate(); FieldConstPtrArray fields; StringArray names; fields.resize(3); names.resize(3); fields[0] = fieldCreate->createScalar(pvInt); fields[1] = fieldCreate->createScalar(pvInt); fields[2] = fieldCreate->createScalar(pvString); names[0] = "severity"; names[0] = "status"; names[0] = "message"; StructureConstPtr alarmField = fieldCreate->createStructure(names,fields); fields.resize(2); names.resize(2); fields[0] = fieldCreate->createScalar(pvDouble); fields[1] = alarmField; names[0] = "value"; names[0] = "alarm"; StructureConstPtr structure = fieldCreate->createStructure(names,fields); PVStructurePtr pv = pvDataCreate->createPVStructure(structure);
Create an alarm structure the easy way.
StandardPVFieldPtr standardPVField = getStandardPVField(); PVStructurePtr pv = standardPVField->scalar(pvDouble,"alarm");
Create a PVStructure with field name example that has a double value field , timeStamp, alarm, and display. Do it the easy way.
StandardPVFieldPtr standardPVField = getStandardPVField(); PVStructurePtr pvStructure = standardPVField->scalar( pvDouble,"timeStamp,alarm.display");
Directory factory has code that implements everything described by the files in directory pv
TypeFunc.cpp implements the functions for the enums defined in pvIntrospecct.h
FieldCreateFactory.cpp automatically creates a single instance of FieldCreate and implements getFieldCreate.
PVDataCreateFactory.cpp automatically creates a single instance of PVDataCreate and implements getPVDataCreate.
PVAuxInfoImpl.cpp implements auxInfo.
Convert.cpp automatically creates a single instance of Convert and implements getConvert.
Other files implement PVData base classes
This package provides utility code:
Note that directory testApp/misc has test code for all the classes in misc. The test code also can be used as examples.
This is adapted from the java.util.BitSet. bitSet.h is:
class BitSet : public Serializable { public: static BitSet::shared_pointer create(uint32 nbits); BitSet(); BitSet(uint32 nbits); virtual ~BitSet(); void flip(uint32 bitIndex); void set(uint32 bitIndex); void clear(uint32 bitIndex); void set(uint32 bitIndex, bool value); bool get(uint32 bitIndex) const; void clear(); int32 nextSetBit(uint32 fromIndex) const; int32 nextClearBit(uint32 fromIndex) const; bool isEmpty() const; uint32 cardinality() const; uint32 size() const; BitSet& operator&=(const BitSet& set); BitSet& operator|=(const BitSet& set); BitSet& operator^=(const BitSet& set); BitSet& operator-=(const BitSet& set); BitSet& operator=(const BitSet &set); void or_and(const BitSet& set1, const BitSet& set2); bool operator==(const BitSet &set) const; bool operator!=(const BitSet &set) const; void toString(StringBuilder buffer); void toString(StringBuilder buffer, int indentLevel) const; private: };
where
Clears all of the bits in this bitSet whose corresponding bit is set in the specified bitSet.
A ByteBuffer is used to serialize and deserialize primitive data. File byteBuffer.h is:
class ByteBuffer { public: ByteBuffer(std::size_t size, int byteOrder = EPICS_BYTE_ORDER) ~ByteBuffer(); void setEndianess(int byteOrder); const char* getBuffer(); void clear(); void flip(); void rewind(); std::size_t getPosition(); void setPosition(std::size_t pos); std::size_t getLimit(); void setLimit(std::size_t limit); std::size_t getRemaining(); std::size_t getSize(); template<typename T> void put(T value) template<typename T> void put(std::size_t index, T value); template<typename T> T get() template<typename T> T get(std::size_t index) void put(const char* src, std::size_t src_offset, std::size_t count); void get(char* dest, std::size_t dest_offset, std::size_t count); template<typename T> inline void putArray(T* values, std::size_t count) template<typename T> inline void getArray(T* values, std::size_t count) template<typename T> inline bool reverse(); inline void align(std::size_t size) void putBoolean( bool value); void putByte ( int8 value); void putShort ( int16 value); void putInt ( int32 value); void putLong ( int64 value); void putFloat ( float value); void putDouble (double value); void putBoolean(std::size_t index, bool value); void putByte (std::size_t index, int8 value); void putShort (std::size_t index, int16 value); void putInt (std::size_t index, int32 value); void putFloat (std::size_t index, float value); void putDouble (std::size_t index, double value); bool getBoolean(); int8 getByte (); int16 getShort (); int32 getInt (); int64 getLong (); float getFloat (); double getDouble (); bool getBoolean(std::size_t index); int8 getByte (std::size_t index); int16 getShort (std::size_t index); int32 getInt (std::size_t index); int64 getLong (std::size_t index); float getFloat (std::size_t index); double getDouble (std::size_t index); const char* getArray(); ... };
class Destroyable { public: POINTER_DEFINITIONS(Destroyable); virtual void destroy() = 0; virtual ~Destroyable() {}; };
/* * Throwing exceptions w/ file+line# and, when possibly, a stack trace * * THROW_EXCEPTION1( std::bad_alloc ); * * THROW_EXCEPTION2( std::logic_error, "my message" ); * * THROW_EXCEPTION( mySpecialException("my message", 42, "hello", ...) ); * * Catching exceptions * * catch(std::logic_error& e) { * fprintf(stderr, "%s happened\n", e.what()); * PRINT_EXCEPTION2(e, stderr); * cout<<SHOW_EXCEPTION(e); * } * * If the exception was not thrown with the above THROW_EXCEPTION* * the nothing will be printed. */
This class provides coordinates activity between threads. One thread can wait for the event and the other signals the event.
class Event; typedef std::tr1::shared_ptr<Event> EventPtr; class Event { public: POINTER_DEFINITIONS(Event); explicit Event(bool = false); ~Event(); void signal(); bool wait (); /* blocks until full */ bool wait ( double timeOut ); /* false if empty at time out */ bool tryWait (); /* false if empty */ private: epicsEventId id; };
where
An Executor is a thread that can execute commands. The user can request that a single command be executed.
class Command; class Executor; typedef std::tr1::shared_ptr<Command> CommandPtr; typedef std::tr1::shared_ptr<Executor> ExecutorPtr; class Command { public: POINTER_DEFINITIONS(Command); virtual ~Command(){} virtual void command() = 0; private: CommandPtr next; friend class Executor; }; class Executor : public Runnable{ public: POINTER_DEFINITIONS(Executor); Executor(String threadName,ThreadPriority priority); ~Executor(); void execute(CommandPtr const &node); virtual void run(); ... };
Command is a class that must be implemented by the code that calls execute. It contains the single virtual method command, which is the command to execute.
Executor has the methods:
typedef epicsMutex Mutex; class Lock : private NoDefaultMethods { public: explicit Lock(Mutex &pm); ~Lock(); void lock(); void unlock(); bool tryLock(); bool ownsLock() ; ... };
Lock is as easy to use as Java synchronize. To protect some object just create a Mutex for the object and then in any method to be synchronized just have code like:
class SomeClass { private Mutex mutex; ... public SomeClass() : mutex(Mutex()) {} ... void method() { Lock xx(mutex); ... }
The method will take the lock when xx is created and release the lock when the current code block completes.
Another example of Lock is initialization code that must initialize only once. This can be implemented as follows:
static void init(void) { static Mutex mutex; Lock xx(mutex); if(alreadyInitialized) return; // initialization }
A messageQueue is for use by code that wants to handle messages without blocking higher priority threads.
class MessageNode; class MessageQueue; typedef std::tr1::shared_ptr<MessageNode> MessageNodePtr; typedef std::vector<MessageNodePtr> MessageNodePtrArray; typedef std::tr1::shared_ptr<MessageQueue> MessageQueuePtr; class MessageNode { public: String getMessage() const; MessageType getMessageType() const; void setMessageNull(); }; class MessageQueue : public Queue<MessageNode> { public: POINTER_DEFINITIONS(MessageQueue); static MessageQueuePtr create(int size); MessageQueue(MessageNodePtrArray &nodeArray); virtual ~MessageQueue(); MessageNodePtr &get(); // must call release before next get void release(); // return (false,true) if message (was not, was) put into queue bool put(String message,MessageType messageType,bool replaceLast); bool isEmpty() ; bool isFull() ; int getClearOverrun(); ... };
A messageNode is a class with two public data members:
A messageQueue is an interface with public methods:
Look at miscTest/testMessageQueue.cpp for an example.
If a class privately extends this class then the compiler can not create any of the following: default constructor, default copy constructror, or default assignment contructor.
/* This is based on Item 6 of * Effective C++, Third Edition, Scott Meyers */ class NoDefaultMethods { protected: // allow by derived objects NoDefaultMethods(){}; ~NoDefaultMethods(){} private: // do not implment NoDefaultMethods(const NoDefaultMethods&); NoDefaultMethods & operator=(const NoDefaultMethods &); };
This provides a queue which has an immutable capacity. When the queue is full the user code is expected to keep using the current element until a new free element becomes avalable.
template <typename T> class Queue { public: POINTER_DEFINITIONS(Queue); typedef std::tr1::shared_ptr<T> queueElementPtr; typedef std::vector<queueElementPtr> queueElementPtrArray; Queue(queueElementPtrArray &); virtual ~Queue(); void clear(); int capacity(); int getNumberFree(); int getNumberUsed(); queueElementPtr & getFree(); void setUsed(queueElementPtr &element); queueElementPtr & getUsed(); void releaseUsed(queueElementPtr &element); ... };
testApp/misc/testQueue.cpp provides an example of how to define a queue.
The queue methods are:
A queue is created as follows:
class MyClass; typedef MyQueueElement<MyClass> MyElement; typedef MyQueue<MyClass> MyQueue; int numElement = 5; ... MyClass *array[numElements]; for(int i=0; i<numElements; i++) { array[i] = new MyClass(); } MyQueue *queue = new MyQueue(array,numElements);
A producer calls getFree and setUsed via code like the following:
MyClass *getFree() { MyElement *element = queue->getFree(); if(element==0) return 0; return element->getObject(); }
A consumer calls getUsed and releaseUsed via code like the following:
while(true) { MyElement *element = queue->getUsed(); if(element==0) break; MyClass *myClass = element->getObject(); // do something with myClass queue->releaseUsed(element); }
A PVField extends Requester. Requester is present so that when database errors are found there is someplace to send a message.
enum MessageType { infoMessage,warningMessage,errorMessage,fatalErrorMessage }; extern String getMessageTypeName(MessageType messageType); extern const size_t messageTypeCount; class Requester { public: POINTER_DEFINITIONS(Requester); virtual ~Requester(){} virtual String getRequesterName() = 0; virtual void message(String const & message,MessageType messageType) = 0; };
where
class SerializableControl; class DeserializableControl; class Serializable; class BitSetSerializable; class SerializableArray; class BitSet; class Field; class SerializableControl { public: virtual ~SerializableControl(){} virtual void flushSerializeBuffer() =0; virtual void ensureBuffer(std::size_t size) =0; virtual void alignBuffer(std::size_t alignment) =0; virtual void cachedSerialize( std::tr1::shared_ptr<const Field> const & field, ByteBuffer* buffer) = 0; }; class DeserializableControl { public: virtual ~DeserializableControl(){} virtual void ensureData(std::size_t size) =0; virtual void alignData(std::size_t alignment) =0; virtual std::tr1::shared_ptr<const Field> cachedDeserialize(ByteBuffer* buffer) = 0; }; class Serializable { public: virtual ~Serializable(){} virtual void serialize(ByteBuffer *buffer, SerializableControl *flusher) const = 0; virtual void deserialize(ByteBuffer *buffer, DeserializableControl *flusher) = 0; }; class BitSetSerializable { public: virtual ~BitSetSerializable(){} virtual void serialize(ByteBuffer *buffer, SerializableControl *flusher,BitSet *bitSet) const = 0; virtual void deserialize(ByteBuffer *buffer, DeserializableControl *flusher,BitSet *bitSet) = 0; }; class SerializableArray : virtual public Serializable { public: virtual ~SerializableArray(){} virtual void serialize(ByteBuffer *buffer, SerializableControl *flusher, std::size_t offset, std::size_t count) const = 0; };
This is a helper class for serialization, which is required for sending and receiving pvData over the nerwork.
class SerializeHelper : public NoDefaultMethods { public: static void writeSize(int s, ByteBuffer* buffer, SerializableControl* flusher); static int readSize(ByteBuffer* buffer, DeserializableControl* control); static void serializeString(const String& value, ByteBuffer* buffer,SerializableControl* flusher); static void serializeSubstring(const String& value, int offset, int count, ByteBuffer* buffer, SerializableControl* flusher); static String deserializeString(ByteBuffer* buffer, DeserializableControl* control); ... };
where
#define POINTER_DEFINITIONS(clazz) \ typedef std::tr1::shared_ptr<clazz> shared_pointer; \ typedef std::tr1::shared_ptr<const clazz> const_shared_pointer; \ typedef std::tr1::weak_ptr<clazz> weak_pointer; \ typedef std::tr1::weak_ptr<const clazz> const_weak_pointer;
Status provides a way to pass status back to client code:
class Status : public epics::pvData::Serializable { public: enum StatusType { /** Operation completed successfully. */ STATUSTYPE_OK, /** Operation completed successfully, but there is a warning message. */ STATUSTYPE_WARNING, /** Operation failed due to an error. */ STATUSTYPE_ERROR, /** Operation failed due to an unexpected error. */ STATUSTYPE_FATAL }; static const char* StatusTypeName[]; static Status OK; Status(); Status(StatusType type, epics::pvData::String const & message); Status(StatusType type, epics::pvData::String const & message, epics::pvData::String stackDump); ~Status() StatusType getType() const; String getMessage() const; String getStackDump() const; bool isOK() const; bool isSuccess() const; String toString() const; void toString(StringBuilder buffer, int indentLevel = 0) const; void serialize(ByteBuffer *buffer, SerializableControl *flusher) const; void serialize(ByteBuffer *buffer, SerializableControl *flusher) const; };
The Status methods are:
The StatusCreate methods are:
enum ThreadPriority { lowestPriority, lowerPriority, lowPriority, middlePriority, highPriority, higherPriority, highestPriority };
class Runnable { public: virtual void run() = 0; }; class Thread; class Thread : public epicsThread, private NoDefaultMethods { public: Thread( String name, ThreadPriority priority, Runnable *runnableReady, epicsThreadStackSizeClass stkcls=epicsThreadStackSmall); ~Thread(); ... };
Runnable must be implement by code that wants to be run via a thread. It has one virtual method: run. Run is the code that is run as a thread. When run compeletes it can not be restarted. If code wants to delete a thread then it MUST arrange that the run returns before the thread can be deleted. An exception is thrown if run remains active when delete is called.
Thread has the methods:
delete pthread;
TimeFunction is a facility that measures the average number of seconds a function call requires. When timeCall is called, it calls function in a loop. It starts with a loop of one iteration. If the total elapsed time is less then .1 seconds it increases the number of iterrations by a factor of 10. It keeps repeating until the elapsed time is greater than .1 seconds. It returns the average number of seconds per call.
class TimeFunctionRequester; class TimeFunction; typedef std::tr1::shared_ptr<TimeFunctionRequester> TimeFunctionRequesterPtr; typedef std::tr1::shared_ptr<TimeFunction> TimeFunctionPtr; class TimeFunctionRequester { public: POINTER_DEFINITIONS(TimeFunctionRequester); virtual ~TimeFunctionRequester(){} virtual void function() = 0; }; class TimeFunction { public: POINTER_DEFINITIONS(TimeFunction); TimeFunction(TimeFunctionRequesterPtr const & requester); ~TimeFunction(); double timeCall(); ... };
TimeFunctionRequester must be implemented by code that wants to time how long a function takes. It has the single method:
TimeFunction has the methods:
This provides a general purpose timer. It allows a user callback to be called after a delay or periodically.
class TimerCallback; class Timer; typedef std::tr1::shared_ptr<TimerCallback> TimerCallbackPtr; typedef std::tr1::shared_ptr<Timer> TimerPtr; class TimerCallback { public: POINTER_DEFINITIONS(TimerCallback); TimerCallback(); virtual ~TimerCallback(){} virtual void callback() = 0; virtual void timerStopped() = 0; }; class Timer : private Runnable { public: POINTER_DEFINITIONS(Timer); Timer(String threadName, ThreadPriority priority); virtual ~Timer(); virtual void run(); void scheduleAfterDelay( TimerCallbackPtr const &timerCallback, double delay); void schedulePeriodic( TimerCallbackPtr const &timerCallback, double delay, double period)); void cancel(TimerCallbackPtr const &timerCallback); bool isScheduled(TimerCallbackPtr const &timerCallback); void toString(StringBuilder builder); ... };
TimerCallback must be implemented by the user. It has the following methods:
In order to schedule a callback client code must allocate a TimerNode It can be used to schedule multiple callbacks. It has the methods:
delete timerNode;
Timer has the methods:
The following is also provided:
class BitSetUtil : private NoDefaultMethods { public: static bool compress(BitSet *bitSet,PVStructure *pvStructure); };
This provides functions that operate on a BitSet for a PVStructure. It currently has only one method: