RecordRep.h

Go to the documentation of this file.

//# RecordRep.h: The representation of a Record
//# Copyright (C) 1996,1997,2000,2001,2005
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: aips2-request@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
//#                        Charlottesville, VA 22903-2475 USA
//#
//#
//# $Id$


#ifndef CASA_RECORDREP_H
#define CASA_RECORDREP_H

//# Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Containers/Block.h>
#include <casacore/casa/Containers/RecordDesc.h>
#include <casacore/casa/Containers/RecordInterface.h>

namespace casacore { //# NAMESPACE CASACORE - BEGIN

//# Forward Declarations
class AipsIO;
class IPosition;
class String;


// <summary>
// The representation of a  Record
// </summary>

// <use visibility=local>
// <reviewed reviewer="Mark Wieringa" date="1996/04/15" tests="tRecord">
// </reviewed>

// <prerequisite>
//   <li> <linkto class="Record">Record</linkto>.
// </prerequisite>
//
// <etymology>
// RecordRep is the REPresentation of a Record.
// </etymology>
//
// <synopsis>
// RecordRep is the actual implementation of a Record object.
// It contains the description and the data. The data is stored as
// a collection of void* pointers to the actual data. By storing
// it in this indirect way, it is easier to extend the data block.
// It also means that RecordFieldPtr objects always have the correct
// pointer and do not need to be adjusted when the data block is extended.
// <p>
// Despite the fact that the data pointers have type void*, the
// functions are completely type safe. This is done by passing the
// type around using the DataType enumeration. The downpart is that
// only types from that enumeration are supported (but that is also
// required by the RecordDesc mechanics).
// <p>
// Note that RecordRep does not know anything about RecordFieldPtr
// objects pointing to its data. Only its mother class Record
// knows about them and handles all cases where the RecordFieldPtr's
// have to be notified.
// </synopsis>
//
// <example>
// RecordRep mirrors all functions in Record.
// </example>
//
// <motivation>
// Having a separate RecordRep class makes copy-on-write possible.
// It also allows derivation of other RecordRep classes (like TableRecordRep),
// while their mother classes are not derived from each other.
// </motivation>
//
// <todo asof="1996/03/12">
//   <li> An implementation where arrays are stored as T*'s would cut down on
//        instantiations (the Arrayness would come back through the creation
//        of the <src>RecordFieldPtr<Array<T> ></src>).
// </todo>


class RecordRep
{
public:
    // Create a record with no fields.
    RecordRep();

    // Create a record with the given description. If it is not possible to 
    // create all fields (for example, if a field of an unsupported type is
    // requested), an exception is thrown.
    // All fields are checked by the field checking function (if defined).
    RecordRep (const RecordDesc& description);

    // Create a copy of other using copy semantics.
    RecordRep (const RecordRep& other);

    // Copy all the data over.
    RecordRep& operator= (const RecordRep& other);
    
    // Delete all data.
    virtual ~RecordRep();

    // Get the comment for this field.
    const String& comment (Int whichField) const;

    // Set the comment for this field.
    void setComment (Int whichField, const String& comment);

    // Describes the current structure of this Record.
    const RecordDesc& description() const;

    // Change the structure of this Record to contain the fields in
    // newDescription. After calling restructure, <src>description() ==
    // newDescription</src>.
    void restructure (const RecordDesc& newDescription, Bool recursive);

    // Returns True if this and other have the same RecordDesc, other
    // than different names for the fields. That is, the number, type and the
    // order of the fields must be identical (recursively for fixed
    // structured sub-Records in this).
    // <note role=caution>
    // <src>thisRecord.conform(thatRecord) == True</src> does not imply
    // <br><src>thatRecord.conform(thisRecord) == True</src>, because
    // a variable record in one conforms a fixed record in that, but
    // not vice-versa.
    // </note>
    Bool conform (const RecordRep& other) const;

    // Copy all data of the Record.
    void copyData (const RecordRep& other);

    // Copy a data field.
    // This can only handle scalars and arrays.
    void copyDataField (DataType type, Int whichField, const void* that) const;

    // Remove a field from the record.
    void removeField (Int whichField);

    // Rename the given field.
    void renameField (const String& newName, Int whichField);

    // Add a field with the given name and value to the record.
    // The data type of the field is determined by the data type of the value.
    // For arrays it is possible to define if the shape is fixed.
    // <group>
    void addDataField (const String& name, DataType type,
                       const IPosition& shape, Bool fixedShape,
                       const void* data);
    void addField (const String& name, const Record& value,
                   RecordInterface::RecordType type);
    // </group>

    // Define a value for the given field.
    // Array conformance rules will not be applied for variable shaped arrays.
    // When the field and value data type mismatch, type promotion
    // of scalars will be done if possible. If not possible, an exception
    // is thrown.
    void defineDataField (Int whichField, DataType type, const void* value);

    // Put the description and data of the Record.
    // It also puts the fixedFlag attribute (of the mother object).
    void putRecord (AipsIO& os, int recordType) const;

    // Get the description and data of the Record.
    // It also gets the fixedFlag attribute (of the mother object).
    void getRecord (AipsIO& os, Int& recordType);

    // Put the data of a record.
    // This is used to write a subrecord, whose description has
    // already been written.
    void putData (AipsIO& os) const;

    // Read the data of a record.
    // This is used to read a subrecord, whose description has
    // already been read.
    void getData (AipsIO& os, uInt version);

    // Used by the RecordFieldPtr classes to attach in a type-safe way to the
    // correct field.
    // <group>
    void* get_pointer (Int whichField, DataType type) const;
    void* get_pointer (Int whichField, DataType type,
                       const String& recordType) const;
    // </group>

    // Merge a field from another record into this record.
    void mergeField (const RecordRep& other, Int whichFieldFromOther,
                     RecordInterface::DuplicatesFlag);

    // Merge all fields from the other record into this record.
    void merge (const RecordRep& other, RecordInterface::DuplicatesFlag);
    
    // Print a record.
    // Print the contents of the record.
    // Only the first <src>maxNrValues</src> of an array will be printed.
    // A value < 0 means the entire array.
    void print (std::ostream&,
                Int maxNrValues = 25,
                const String& indent="") const;

protected:
    // Utility functions to avoid code duplication in the public member 
    // functions.
    // <group>
    void delete_myself (uInt nfields);
    void copy_other (const RecordRep& other);
    // </group>

    // Get the field number for a given name.
    virtual Int fieldNumber (const String& name) const;

    // Add the data pointer to the data block.
    // The block is extended when needed.
    void addDataPtr (void* ptr);

    // Remove a data pointer add the given index.
    void removeDataPtr (Int index);

    // Check if the shape of the data array matches the shape of a
    // fixed-shaped array in the description.
    void checkShape (DataType type, const IPosition& shape,
                     const void* value, const String& fieldName);

    // Add a field to the description.
    virtual void addFieldToDesc (const String& name, DataType type,
                                 const IPosition& shape, Bool fixedShape);

    // Remove a data field.
    virtual void removeData (Int whichField, void* ptr, void* vecptr);

    // Remove a field from the description.
    virtual void removeFieldFromDesc (Int whichField);

    // Create a data field for the given type and shape.
    // This can only handle scalars and arrays.
    void* createDataField (DataType type, const IPosition& shape);

    // Delete a data field.
    // This can only handle scalars and arrays.
    void deleteDataField (DataType type, void* ptr, void* vecptr);

    // Copy a data field.
    // This can only handle scalars and arrays.
    void copyDataField (DataType type, void* ptr, const void* that) const;

    // Print a data field.
    // This can only handle scalars and arrays.
    void printDataField (std::ostream& os, DataType type,
                         const String& indent, Int maxNrValues,
                         const void* ptr) const;

    // Put a data field.
    // This can only handle scalars and arrays.
    void putDataField (AipsIO& os, DataType type, const void* ptr) const;

    // Get a data field.
    // This can only handle scalars and arrays.
    void getDataField (AipsIO& os, DataType type, void* ptr);

    // Make an array for a scalar data field.
    // It shares the data, so a change in the data is reflected in the array.
    // It is used to be able to access a scalar as an 1D array.
    void makeDataVec (Int whichField, DataType type);

    // Get a Scalar/ArrayKeywordSet object as a Record.
    // (type 0 = ScalarKeywordSet;  type 1 = ArrayKeywordSet).
    void getKeySet (AipsIO& os, uInt version, uInt type);

    // Get the description of a keyword set as a RecordDesc.
    void getKeyDesc (AipsIO& os, RecordDesc& desc);

    // Get the scalar values of a keyword set.
    void getScalarKeys (AipsIO& os);

    // Get the array values of a keyword set.
    void getArrayKeys (AipsIO& os);


    // Holds the structure of this Record.
    RecordDesc   desc_p;
    // Pointers to data values.
    Block<void*> data_p;
    // Pointers to a vector of a scalar (to access a scalar as an array).
    Block<void*> datavec_p;
    // #Entries used in data_p.
    uInt         nused_p;
};


inline const RecordDesc& RecordRep::description() const
{
    return desc_p;
}

inline const String& RecordRep::comment (Int whichField) const
{
    return desc_p.comment (whichField);
}

inline void RecordRep::setComment (Int whichField, const String& comment)
{
    desc_p.setComment (whichField, comment);
}

inline void RecordRep::renameField (const String& newName, Int whichField)
{
    desc_p.renameField (newName, whichField);
}



} //# NAMESPACE CASACORE - END

#endif