QuantumHolder.h

This class can be used to handle a heterogeneous list of Quantums, and can handle toRecord() and fromRecord() conversions. A QuantumHolder is created empty, from a Quantum (e.g. a Quantum<Double>) or a Quantum<Vector<Float> >).

The accepted range of Quantums is:

Quantum<Int>, Quantum<Float>, Quantum<Double> == Quantity
Quantum<Complex>, Quantum<DComplex>
Quantum<Vector<Int> >, Quantum<Vector<Float> >, Quantum<Vector<Double> >
Quantum<Vector<Complex> >, Quantum<Vector<DComplex> >
Quantum<Array<Int> >, Quantum<Array<Float> >, Quantum<Array<Double> >
Quantum<Array<Complex> >, Quantum<Array<DComplex> >

Scalars in the same group can be converted to any in the same group (e.g. Int to Double); Vectors of length 1 can be converted to scalars in the corresponding group; Scalars can always be converted to Vectors in the corresponding group. Real scalar values can be converted to Complex values. Vectors cannot be converted to other type vectors.

Checks on the contents can be made with functions like isQuantity and the contents can be obtained with functions like asQuantity. It is an error to try and retrieve a Quantum of the wrong type and doing so will generate an exception (AipsError).

Example

	TableRecord rec;		// an empty record
	Quantity x(12.5, "km/s");	// a Quantity
	String error;			// an error message
	if (!QuantumHolder(x).toRecord(error, rec)) {  // make record
		cout << error << endl;
	};
	Record grec;		        // a Record
	if (!QuantumHolder(x).toRecord(error, grec)) {  // make record
		cout << error << endl;
	};
 // Note that for GlishRecords use can be made of the
 // GlishRecord::to/fromrecord() methods.

Motivation

To make general conversions between Quantums and records, without knowing the actual Quantum being converted.

Member Description

QuantumHolder()

Creates an empty holder

QuantumHolder(const QBase &in)

Create from a Quantum (copy semantics)

QuantumHolder(const QuantumHolder &other)

Copy a holder (copy semantics)

~QuantumHolder()

QuantumHolder &operator=(const QuantumHolder &other)

Assignment (copy semantics)

Bool isEmpty() const
Bool isQuantum() const
Bool isScalar() const
Bool isVector() const
Bool isArray() const
Bool isReal() const
Bool isComplex() const
Bool isQuantity() const
Bool isQuantumDouble() const
Bool isQuantumFloat() const
Bool isQuantumInt() const
Bool isQuantumComplex() const
Bool isQuantumDComplex() const
Bool isQuantumVectorDouble() const
Bool isQuantumVectorFloat() const
Bool isQuantumVectorInt() const
Bool isQuantumVectorComplex() const
Bool isQuantumVectorDComplex() const
Bool isQuantumArrayDouble() const
Bool isQuantumArrayFloat() const
Bool isQuantumArrayInt() const
Bool isQuantumArrayComplex() const
Bool isQuantumArrayDComplex() const

Check if it holds a Quantity. Note that a Vector of length 1 will give True to scalar questions.

Int nelements() const
Int ndim() const

Get number of numeric elements (1 if scalar, else vector length) or dimensions (0 if scalar)

Thrown Exceptions

AipsError if holder empty

const QBase &asQuantum() const
const Quantum<Double> &asQuantity()
const Quantum<Double> &asQuantumDouble()
const Quantum<Float> &asQuantumFloat()
const Quantum<Int> &asQuantumInt()
const Quantum<Complex> &asQuantumComplex()
const Quantum<DComplex> &asQuantumDComplex()
const Quantum<Vector<Double> > &asQuantumVectorDouble()
const Quantum<Vector<Float> > &asQuantumVectorFloat()
const Quantum<Vector<Int> > &asQuantumVectorInt()
const Quantum<Vector<Complex> > &asQuantumVectorComplex()
const Quantum<Vector<DComplex> > &asQuantumVectorDComplex()
const Quantum<Array<Double> > &asQuantumArrayDouble()
const Quantum<Array<Float> > &asQuantumArrayFloat()
const Quantum<Array<Int> > &asQuantumArrayInt()
const Quantum<Array<Complex> > &asQuantumArrayComplex()
const Quantum<Array<DComplex> > &asQuantumArrayDComplex()

Get a Quantum from the holder (with lifetime as long as holder exists). Conversions done if necessary and as described in introduction.

Thrown Exceptions

AipsError if holder empty or no conversion possible

virtual Bool fromRecord(String &error, const RecordInterface &in)
virtual Bool fromString(String &error, const String &in)

Create a Quantum from a record or a string. A valid record will contain the following fields:

value: contains a numeric value of Int, Float, Double, Complex, DComplex or a vector thereof
unit: a string with a valid unit string.

A valid string will be one of the special time/angle formats or a value with a valid unit string. Illegal values or units will return False and write an error message.

virtual Bool toRecord(String &error, RecordInterface &out) const

Create a record from a Quantum. A False return and an error message is only generated if there is no valid Quantum in the holder.

virtual const String &ident() const

Return identification

void toReal(const uInt &tp)

Convert to a different real scalar quantum

void toComplex(const uInt &tp)

Convert to a different complex scalar quantum

void toVector()

Convert scalar to Vector

void toArray()

Convert scalar to Array