Class encapsulates user-options for a bootstrap block from an SDD file. More...

#include <SDDBootStrap.h>

Public Types
enum	TYPE_OF_SDD { DATA, RECORDS }
enum	SDD_VERSION { ORIGINAL, CURRENT }
Public Member Functions
	SDDBootStrap ()
	Default constructor : empty CURRENT version NOT attached to a file.
	SDDBootStrap (CountedPtr< fstream > streamPtr)
	create from an fstream ptr in CountedPtr<fstream>
	SDDBootStrap (const SDDBootStrap &other)
	from an existing SDDBootStrap, copies all values
	~SDDBootStrap ()
SDDBootStrap &	operator= (const SDDBootStrap &other)
	The assignment operator, does a full copy.
void	attach (CountedPtr< fstream > newStreamPtr)
	Attach.
void	write ()
	write it out, must already be attached
CountedPtr< fstream > &	theStream ()
	Get the CountedPtr<fstream> in use here.
uInt	nIndexRec () const
	These just return the values.
uInt	nDataRec () const
uInt	bytesPerRecord () const
uInt	bytesPerEntry () const
uInt	maxEntryUsed () const
uInt	counter () const
uInt	type () const
uInt	version () const
uInt	maxEntries () const
	Maximum index entries that can be used, based on the values in the bootstrap.
uInt	entriesPerRecord () const
	the numebr of entries per record
void	setNIndexRec (uInt newValue)
	Set things that are allowed to be set.
void	setNDataRec (uInt newValue)
void	setBytesPerEntry (uInt newValue)
void	setVersion (SDD_VERSION newValue)
void	setType (TYPE_OF_SDD newValue)
Bool	setMaxEntryUsed (uInt newValue)
	this requires a sanity check to ensure it is less than maxEntries
Bool	hasChanged ()
	This returns True if the bootstrap on disk differs from the one here.
void	sync ()
	sync() re-reads the values from disk.
Private Types
enum	{ N_INDEX_REC, N_DATA_REC, BYTES_PER_REC, BYTES_PER_ENTRY, MAX_ENTRY_USED, COUNTER, TYPE, VERSION }
	this enum describes where things are in the bootstrap block for ORIGINAL version files, these are short (2-byte) unsigned integers for CURRENT version files, these are long (4-byte) unsigned integers all unused space is filled with zeros (both ORIGINAL and CURRECT). More...
Private Attributes
uInt	nIndexRec_p
uInt	nDataRec_p
uInt	bytesPerRec_p
uInt	bytesPerEntry_p
uInt	maxEntryUsed_p
uInt	counter_p
uInt	type_p
uInt	version_p
SDDBlock *	bs_p
CountedPtr< fstream >	theFile_p

Detailed Description

Class encapsulates user-options for a bootstrap block from an SDD file.

Intended use:

Public interface

Prerequisite

SDDFile
SDDIndex
SDDData
The SDD data format

Etymology

SDD is the Single Dish Data format used by UniPOPS. It is also the on-line data format at the NRAO 12-m. The bootstrap block is the first 512 bytes of an SDD file. It contains information that describes the file and allows the rest of the file to be read correctly. This class encapsulates that data.

Synopsis

This class encapsulates the SDD bootstrap block. It can be initialzed from a CountedPtr<fstream> object. In order to be written to disk it must be attached to a CountedPtr<fstream> object. The class correctly positions the fstream to the start of the file. The information in the bootstrap is retrieved via member functions. Most of the information in the bootstrap can be set. The class does basic sanity checking on the information in the bootstrap. It is expected that this class will be used with other SDD classes (most users will simply use SDDFile). The hasChanged() function checks the internal copy of the bootstrap block with the block on disk (if attached) and returns True if the file has changed (i.e. whats on disk does NOT match this object) and False if it has not changed.

Example

Create an SDDBootStrap from a file on disk. Print some information, set some values, write it out to the same file.

        fstream* file_ptr = new fstream("file_name", ios::nocreate);
        CountedPtr<fstream> file(file_ptr);
        SDDBootStrap bs(file);
        cout << "Number of index records : " << bs.nIndexRec() << endl;
        cout << "Number of data records : " << bs.nDataRec() << endl;
        cout << "Maximum index entry in use : " << bs.maxEntryUsed() << endl;
   
        // set some new values
        bs.setNDataRec(bs.nDataRec()+5);
        if (!bs.setMaxEntryUsed(bs.maxEntryUsed()+1)) {
           cout << "unable to set max entry used" << endl;
           // do something appropriate here
        }
   
        // write it out
        bs.write();

Motivation

The SDD file format is used by UniPOPS and the on-line data system at the NRAO 12-m. It is necessary to read this type of data directly into aips++. Specifically, a table storage manager can be written to make an SDD file look like a table. Underneath that storage manager are the SDD classes to encapsulate the data.

To Do

I'm still not happy with the update mechanism
Need to be more explicit about RO versus RW or is that info available directly from the fstream?

Definition at line 119 of file SDDBootStrap.h.

Member Enumeration Documentation

anonymous enum [private]

this enum describes where things are in the bootstrap block for ORIGINAL version files, these are short (2-byte) unsigned integers for CURRENT version files, these are long (4-byte) unsigned integers all unused space is filled with zeros (both ORIGINAL and CURRECT).

Enumerator:

N_INDEX_REC
N_DATA_REC
BYTES_PER_REC
BYTES_PER_ENTRY
MAX_ENTRY_USED
COUNTER	largest index entry in use
TYPE	changes, wraps back to 0 at max unsigned 4-byte integer
VERSION

Definition at line 193 of file SDDBootStrap.h.

enum SDDBootStrap::SDD_VERSION

Enumerator:

ORIGINAL
CURRENT

Definition at line 126 of file SDDBootStrap.h.

enum SDDBootStrap::TYPE_OF_SDD

Enumerator:

DATA
RECORDS

Definition at line 123 of file SDDBootStrap.h.

Constructor & Destructor Documentation

SDDBootStrap::SDDBootStrap ( )

Default constructor : empty CURRENT version NOT attached to a file.

SDDBootStrap::SDDBootStrap ( CountedPtr< fstream > streamPtr )

create from an fstream ptr in CountedPtr<fstream>

SDDBootStrap::SDDBootStrap ( const SDDBootStrap & other )

from an existing SDDBootStrap, copies all values

SDDBootStrap::~SDDBootStrap ( )

Member Function Documentation

void SDDBootStrap::attach ( CountedPtr< fstream > newStreamPtr )

Attach.

uInt SDDBootStrap::bytesPerEntry ( ) const [inline]

Definition at line 155 of file SDDBootStrap.h.

References bytesPerEntry_p.

uInt SDDBootStrap::bytesPerRecord ( ) const [inline]

Definition at line 154 of file SDDBootStrap.h.

References bytesPerRec_p.

uInt SDDBootStrap::counter ( ) const [inline]

Definition at line 157 of file SDDBootStrap.h.

References counter_p.

uInt SDDBootStrap::entriesPerRecord ( ) const [inline]

the numebr of entries per record

Definition at line 167 of file SDDBootStrap.h.

References bytesPerEntry_p, and bytesPerRec_p.

Bool SDDBootStrap::hasChanged ( )

This returns True if the bootstrap on disk differs from the one here.

It does not change the bootstrap on disk.

uInt SDDBootStrap::maxEntries ( ) const [inline]

Maximum index entries that can be used, based on the values in the bootstrap.

Definition at line 163 of file SDDBootStrap.h.

References bytesPerEntry_p, bytesPerRec_p, and nIndexRec_p.

Referenced by setMaxEntryUsed().

uInt SDDBootStrap::maxEntryUsed ( ) const [inline]

Definition at line 156 of file SDDBootStrap.h.

References maxEntryUsed_p.

uInt SDDBootStrap::nDataRec ( ) const [inline]

Definition at line 153 of file SDDBootStrap.h.

References nDataRec_p.

uInt SDDBootStrap::nIndexRec ( ) const [inline]

These just return the values.

Definition at line 152 of file SDDBootStrap.h.

References nIndexRec_p.

SDDBootStrap& SDDBootStrap::operator= ( const SDDBootStrap & other )

The assignment operator, does a full copy.

void SDDBootStrap::setBytesPerEntry ( uInt newValue ) [inline]

Definition at line 173 of file SDDBootStrap.h.

References bytesPerEntry_p.

Bool SDDBootStrap::setMaxEntryUsed ( uInt newValue ) [inline]

this requires a sanity check to ensure it is less than maxEntries

Definition at line 211 of file SDDBootStrap.h.

References maxEntries(), and maxEntryUsed_p.

void SDDBootStrap::setNDataRec ( uInt newValue ) [inline]

Definition at line 172 of file SDDBootStrap.h.

References nDataRec_p.

void SDDBootStrap::setNIndexRec ( uInt newValue ) [inline]

Set things that are allowed to be set.

Definition at line 171 of file SDDBootStrap.h.

References nIndexRec_p.

void SDDBootStrap::setType ( TYPE_OF_SDD newValue ) [inline]

Definition at line 175 of file SDDBootStrap.h.

References type_p.

void SDDBootStrap::setVersion ( SDD_VERSION newValue ) [inline]

Definition at line 174 of file SDDBootStrap.h.

References version_p.

void SDDBootStrap::sync ( )

sync() re-reads the values from disk.

Any internal values will be forgotten.

CountedPtr<fstream>& SDDBootStrap::theStream ( ) [inline]

Get the CountedPtr<fstream> in use here.

Definition at line 149 of file SDDBootStrap.h.

References theFile_p.

uInt SDDBootStrap::type ( ) const [inline]

Definition at line 158 of file SDDBootStrap.h.

References type_p.

uInt SDDBootStrap::version ( ) const [inline]

Definition at line 159 of file SDDBootStrap.h.

References version_p.

void SDDBootStrap::write ( )

write it out, must already be attached

Member Data Documentation

SDDBlock* SDDBootStrap::bs_p [private]

Definition at line 207 of file SDDBootStrap.h.

uInt SDDBootStrap::bytesPerEntry_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by bytesPerEntry(), entriesPerRecord(), maxEntries(), and setBytesPerEntry().

uInt SDDBootStrap::bytesPerRec_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by bytesPerRecord(), entriesPerRecord(), and maxEntries().

uInt SDDBootStrap::counter_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by counter().

uInt SDDBootStrap::maxEntryUsed_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by maxEntryUsed(), and setMaxEntryUsed().

uInt SDDBootStrap::nDataRec_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by nDataRec(), and setNDataRec().

uInt SDDBootStrap::nIndexRec_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by maxEntries(), nIndexRec(), and setNIndexRec().

CountedPtr<fstream> SDDBootStrap::theFile_p [private]

Definition at line 208 of file SDDBootStrap.h.

Referenced by theStream().

uInt SDDBootStrap::type_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by setType(), and type().

uInt SDDBootStrap::version_p [private]

Definition at line 204 of file SDDBootStrap.h.

Referenced by setVersion(), and version().

The documentation for this class was generated from the following file:

code/nrao/SDD/SDDBootStrap.h

Public Types

Public Member Functions

Private Types

Private Attributes

Detailed Description

Intended use:

Prerequisite

Etymology

Synopsis

Example

Motivation

To Do

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation