casacore::ISMIndex Class Reference

The Index of the Incremental Storage Manager. More...

#include <ISMIndex.h>

Public Member Functions
	ISMIndex (ISMBase *parent)
	Create a ISMIndex object with the given parent for a new table. More...
	~ISMIndex ()
	The destructor closes the file (if opened). More...
void	addRow (rownr_t nrrow)
	Add a row. More...
Int	removeRow (rownr_t rownr)
	Remove a row from the index. More...
uInt	getBucketNr (rownr_t rownr, rownr_t &bucketStartRow, rownr_t &bucketNrrow) const
	Get the bucket number for the given row. More...
void	get (AipsIO &os)
	Read the bucket index from the AipsIO object. More...
void	put (AipsIO &os)
	Write the bucket index into the AipsIO object. More...
void	addBucketNr (rownr_t rownr, uInt bucketNr)
	Add a bucket number to the index. More...
Bool	nextBucketNr (uInt &cursor, rownr_t &bucketStartRow, rownr_t &bucketNrrow, uInt &bucketNr) const
	Get the number of the next bucket from the index and return it in bucketNr. More...
void	show (std::ostream &) const
	Show the index. More...

Private Member Functions
	ISMIndex (const ISMIndex &)
	Forbid copy constructor. More...
ISMIndex &	operator= (const ISMIndex &)
	Forbid assignment. More...
uInt	getIndex (rownr_t rownr) const
	Get the index of the bucket containing the given row. More...

Private Attributes
ISMBase *	stmanPtr_p
	Pointer to the parent storage manager. More...
uInt	nused_p
	Number of entries used. More...
Block< rownr_t >	rows_p
	Rownr index (i.e. More...
Block< uInt >	bucketNr_p
	Corresponding bucket number. More...

Detailed Description

The Index of the Incremental Storage Manager.

Intended use:

Internal

Review Status

Reviewed By:

UNKNOWN

Date Reviewed:

before2004/08/25

Prerequisite

• ISMBase

Etymology

ISMIndex represents the index in the Incremental Storage Manager.

Synopsis

ISMIndex maintains an index of all buckets in an ISM (Incremental Storage Manager). The index consists of the starting row number and the bucket number of each bucket in the BucketCache object of the ISM. When the ISM is opened, the entire index is read in and kept in memory. When the ISM is closed or flushed, the index is written back after all buckets in the file. A little header at the beginning of the file indicates the starting offset of the index.

Motivation

ISMIndex encapsulates all operations on the ISM index.

Definition at line 79 of file ISMIndex.h.

Constructor & Destructor Documentation

casacore::ISMIndex::ISMIndex ( ISMBase *  parent )

explicit

Create a ISMIndex object with the given parent for a new table.

It keeps the pointer to its parent (but does not own it).

casacore::ISMIndex::~ISMIndex

(

)

The destructor closes the file (if opened).

casacore::ISMIndex::ISMIndex ( const ISMIndex &  )

private

Forbid copy constructor.

Member Function Documentation

void casacore::ISMIndex::addBucketNr	(	rownr_t	rownr,
		uInt	bucketNr
	)

Add a bucket number to the index.

Argument rownr gives the starting row of the bucket. It is used to add the bucket number at the correct place (such that the row numbers are kept in ascending order).

void casacore::ISMIndex::addRow

(

rownr_t

nrrow

)

Add a row.

void casacore::ISMIndex::get

(

AipsIO &

os

)

Read the bucket index from the AipsIO object.

uInt casacore::ISMIndex::getBucketNr	(	rownr_t	rownr,
		rownr_t &	bucketStartRow,
		rownr_t &	bucketNrrow
	)		const

Get the bucket number for the given row.

Also return the start row of the bucket and the number of rows in it.

uInt casacore::ISMIndex::getIndex ( rownr_t  rownr ) const

private

Get the index of the bucket containing the given row.

Bool casacore::ISMIndex::nextBucketNr	(	uInt &	cursor,
		rownr_t &	bucketStartRow,
		rownr_t &	bucketNrrow,
		uInt &	bucketNr
	)		const

Get the number of the next bucket from the index and return it in bucketNr.

The starting row of that bucket and the number of rows in the bucket are also returned. Return status False indicates that no more buckets are available.
The start of the iteration is indicated by cursor=0. The first bucket returned is the bucket containing the rownr given in bucketStartRow (thus set bucketStartRow to 0 if you want to start at the first bucket).
The next iterations return the next bucket number and fill the starting row and number of rows.

ISMIndex& casacore::ISMIndex::operator= ( const ISMIndex &  )

private

Forbid assignment.

void casacore::ISMIndex::put

(

AipsIO &

os

)

Write the bucket index into the AipsIO object.

Int casacore::ISMIndex::removeRow

(

rownr_t

rownr

)

Remove a row from the index.

If the result of this is that the entire bucket gets empty, that bucketnr is returned. Otherwise -1 is returned.

void casacore::ISMIndex::show

(

std::ostream &

)

const

Show the index.

Member Data Documentation

Block<uInt> casacore::ISMIndex::bucketNr_p

private

Corresponding bucket number.

Definition at line 149 of file ISMIndex.h.

uInt casacore::ISMIndex::nused_p

private

Number of entries used.

Definition at line 145 of file ISMIndex.h.

Block<rownr_t> casacore::ISMIndex::rows_p

private

Rownr index (i.e.

row rows_p[i] starts in bucketNr_p[i]).

Definition at line 147 of file ISMIndex.h.

ISMBase* casacore::ISMIndex::stmanPtr_p

private

Pointer to the parent storage manager.

Definition at line 143 of file ISMIndex.h.

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

• tables/DataMan/ISMIndex.h