casa::BucketBuffered Class Reference

Use buffered file IO for buckets in a part of a file. More...

#include <BucketBuffered.h>

Inheritance diagram for casa::BucketBuffered:

List of all members.

Public Member Functions
	BucketBuffered (BucketFile *file, Int64 startOffset, uInt bucketSize, uInt nrOfBuckets)
	Create the object for (part of) a file.
virtual	~BucketBuffered ()
char *	getBuffer ()
	Get a pointer to the buffer.
void	read (uInt bucketNr, uInt bucketOffset, uInt nbytes, uInt bufferOffset=0)
	Read the given part into the internal buffer at the given offset.
void	write (uInt bucketNr, uInt bucketOffset, uInt nbytes)
	Write the given part from the internal buffer.
Private Member Functions
	BucketBuffered (const BucketBuffered &)
	Copy constructor is not possible.
BucketBuffered &	operator= (const BucketBuffered &)
	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.
Private Attributes
char *	itsBuffer
	Data buffer.

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Detailed Description

Use buffered file IO for buckets in a part of a file.

Intended use:

Public interface

Review Status

Reviewed By:

UNKNOWN

Date Reviewed:

before2004/08/25

Prerequisite

• BucketFile

Synopsis

BucketBuffered 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-buffered 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-buffering behaves much better.

Definition at line 75 of file BucketBuffered.h.

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Constructor & Destructor Documentation

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

Create the object for (part of) a file.

The file part buffered 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.

virtual casa::BucketBuffered::~BucketBuffered

(

)

[virtual]

casa::BucketBuffered::BucketBuffered

(

const BucketBuffered &

)

[private]

Copy constructor is not possible.

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Member Function Documentation

virtual void casa::BucketBuffered::doExtend

(

uInt

nrBucket

)

[private, virtual]

Extend the file with the given number of buckets.

Implements casa::BucketBase.

virtual void casa::BucketBuffered::doFlush

(

)

[private, virtual]

Flush the file.

Implements casa::BucketBase.

virtual void casa::BucketBuffered::doResync

(

)

[private, virtual]

Do the actual resync-ing.

Implements casa::BucketBase.

char* casa::BucketBuffered::getBuffer

(

)

[inline]

Get a pointer to the buffer.

Definition at line 89 of file BucketBuffered.h.

References itsBuffer.

virtual void casa::BucketBuffered::initializeBuckets

(

uInt

bucketNr

)

[private, virtual]

Initialize the bucket buffer.

The uninitialized buckets before this bucket are also initialized.

Implements casa::BucketBase.

BucketBuffered& casa::BucketBuffered::operator=

(

const BucketBuffered &

)

[private]

Assignment is not possible.

void casa::BucketBuffered::read	(	uInt	bucketNr,
		uInt	bucketOffset,
		uInt	nbytes,
		uInt	bufferOffset = 0
	)

Read the given part into the internal buffer at the given offset.

void casa::BucketBuffered::write	(	uInt	bucketNr,
		uInt	bucketOffset,
		uInt	nbytes
	)

Write the given part from the internal buffer.

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Member Data Documentation

char* casa::BucketBuffered::itsBuffer [private]

Data buffer.

Definition at line 121 of file BucketBuffered.h.

Referenced by getBuffer().

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

• casacore/casa/IO/BucketBuffered.h