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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 (uInt nrrow)
 Add a row. More...
 
Int removeRow (uInt rownr)
 Remove a row from the index. More...
 
uInt getBucketNr (uInt rownr, uInt &bucketStartRow, uInt &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 (uInt rownr, uInt bucketNr)
 Add a bucket number to the index. More...
 
Bool nextBucketNr (uInt &cursor, uInt &bucketStartRow, uInt &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...
 
ISMIndexoperator= (const ISMIndex &)
 Forbid assignment. More...
 
uInt getIndex (uInt rownr) const
 Get the index of the bucket containing the given row. More...
 

Private Attributes

ISMBasestmanPtr_p
 Pointer to the parent storage manager. More...
 
uInt nused_p
 Number of entries used. More...
 
Block< uIntrows_p
 Rownr index (i.e. More...
 
Block< uIntbucketNr_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

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 ( uInt  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 ( uInt  nrrow)

Add a row.

void casacore::ISMIndex::get ( AipsIO os)

Read the bucket index from the AipsIO object.

uInt casacore::ISMIndex::getBucketNr ( uInt  rownr,
uInt bucketStartRow,
uInt 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 ( uInt  rownr) const
private

Get the index of the bucket containing the given row.

Bool casacore::ISMIndex::nextBucketNr ( uInt cursor,
uInt bucketStartRow,
uInt 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 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 ( uInt  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<uInt> 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.


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