casa::BucketMapped Class Reference

Use file mapping for buckets in a part of a file. More...

#include <BucketMapped.h>

Inheritance diagram for casa::BucketMapped:

List of all members.

Public Member Functions
	BucketMapped (BucketFile *file, Int64 startOffset, uInt bucketSize, uInt nrOfBuckets)
	Create the cache for (part of) a file.
	~BucketMapped ()
	Unmap the file.
const char *	getBucket (uInt bucketNr)
	Get a readonly pointer to the given bucket in memory.
char *	getrwBucket (uInt bucketNr)
	Get a writable pointer to the given bucket in memory.
Private Member Functions
	BucketMapped (const BucketMapped &)
	Copy constructor is not possible.
BucketMapped &	operator= (const BucketMapped &)
	Assignment is not possible.
virtual void	doFlush ()
	Flush the file.
virtual void	doResync ()
	Do the actual resync-ing.
virtual void	doExtend (uInt nrBucket)
	Extend the file with the given number of buckets.
virtual void	initializeBuckets (uInt bucketNr)
	Initialize the bucket buffer.

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Detailed Description

Use file mapping for buckets in a part of a file.

Intended use:

Public interface

Review Status

Reviewed By:

UNKNOWN

Date Reviewed:

before2004/08/25

Prerequisite

• BucketFile

Etymology

BucketMapped uses memory-mapped files for bucket access.

Synopsis

BucketMapped is similar to class BucketCache and is meant to be used by the storage managers of the Table System.

It gives access to buckets in a file by means of memory-mapped files. However, its functionality is a subset of BucketCache and is only meant to be used by the Tiled Storage Managers. If The Standard and Incremental Storage Manager also want to use it, functions like extend needs to be added to this class. Also support for a free bucket list needs to be added.

Motivation

Use of BucketCache is sub-optimal when having large buckets and more or less random IO. Memory-mapping behaves much better.

Definition at line 75 of file BucketMapped.h.

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Constructor & Destructor Documentation

casa::BucketMapped::BucketMapped	(	BucketFile *	file,
		Int64	startOffset,
		uInt	bucketSize,
		uInt	nrOfBuckets
	)

Create the cache for (part of) a file.

The file part mapped into memory starts at startOffset. Its length is bucketSize*nrOfBuckets bytes. If the file is smaller, the remainder is indicated as an extension similarly to the behaviour of function extend.

casa::BucketMapped::~BucketMapped

(

)

Unmap the file.

casa::BucketMapped::BucketMapped

(

const BucketMapped &

)

[private]

Copy constructor is not possible.

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Member Function Documentation

virtual void casa::BucketMapped::doExtend

(

uInt

nrBucket

)

[private, virtual]

Extend the file with the given number of buckets.

Implements casa::BucketBase.

virtual void casa::BucketMapped::doFlush

(

)

[private, virtual]

Flush the file.

Implements casa::BucketBase.

virtual void casa::BucketMapped::doResync

(

)

[private, virtual]

Do the actual resync-ing.

Implements casa::BucketBase.

const char* casa::BucketMapped::getBucket

(

uInt

bucketNr

)

Get a readonly pointer to the given bucket in memory.

Referenced by getrwBucket().

char* casa::BucketMapped::getrwBucket

(

uInt

bucketNr

)

[inline]

Get a writable pointer to the given bucket in memory.

It sets the hasWritten flag.

Definition at line 94 of file BucketMapped.h.

References getBucket(), casa::BucketBase::itsHasWritten, and casa::True.

virtual void casa::BucketMapped::initializeBuckets

(

uInt

bucketNr

)

[private, virtual]

Initialize the bucket buffer.

The uninitialized buckets before this bucket are also initialized.

Implements casa::BucketBase.

BucketMapped& casa::BucketMapped::operator=

(

const BucketMapped &

)

[private]

Assignment is not possible.

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

• casacore/casa/IO/BucketMapped.h