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BucketBuffered.h
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//# BucketBuffered.h: Use buffered file IO for buckets in a part of a file
//# Copyright (C) 2010
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//# Internet email: casa-feedback@nrao.edu.
//# Postal address: AIPS++ Project Office
//# National Radio Astronomy Observatory
//# 520 Edgemont Road
//# Charlottesville, VA 22903-2475 USA
#ifndef CASA_BUCKETBUFFERED_H
#define CASA_BUCKETBUFFERED_H
//# Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/IO/BucketBase.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
//# Forward Declarations.
class FilebufIO;
// <summary>
// Use buffered file IO for buckets in a part of a file
// </summary>
// <use visibility=export>
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="" demos="">
// </reviewed>
// <prerequisite>
//# Classes you should understand before using this one.
// <li> <linkto class=BucketFile>BucketFile</linkto>
// </prerequisite>
// <synopsis>
// BucketBuffered is similar to class
// <linkto class=BucketCache>BucketCache</linkto> 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 <src>extend</src>
// needs to be added to this class. Also support for a free bucket list needs
// to be added.
// </synopsis>
// <motivation>
// Use of BucketCache is sub-optimal when having large buckets and more or
// less random IO. Memory-buffering behaves much better.
// </motivation>
class BucketBuffered: public BucketBase
{
public:
// 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.
BucketBuffered (BucketFile* file, Int64 startOffset, uInt bucketSize,
uInt nrOfBuckets);
virtual ~BucketBuffered();
// Get a pointer to the buffer.
char* getBuffer()
{ return itsBuffer; }
// Read the given part into the internal buffer at the given offset.
void read (uInt bucketNr, uInt bucketOffset, uInt nbytes,
uInt bufferOffset=0);
// Write the given part from the internal buffer.
void write (uInt bucketNr, uInt bucketOffset, uInt nbytes);
private:
// Copy constructor is not possible.
BucketBuffered (const BucketBuffered&);
// Assignment is not possible.
BucketBuffered& operator= (const BucketBuffered&);
// Flush the file.
virtual void doFlush();
// Do the actual resync-ing.
virtual void doResync();
// Extend the file with the given number of buckets.
virtual void doExtend (uInt nrBucket);
// Initialize the bucket buffer.
// The uninitialized buckets before this bucket are also initialized.
virtual void initializeBuckets (uInt bucketNr);
// Data buffer.
char* itsBuffer;
};
} //# NAMESPACE CASACORE - END
#endif
casacore::BucketBase::BucketBase
BucketBase(BucketFile *file, Int64 startOffset, uInt bucketSize, uInt nrOfBuckets)
Create the bucket access for (part of) a file.
casacore::BucketBuffered::operator=
BucketBuffered & operator=(const BucketBuffered &)
Assignment is not possible.
casacore::BucketBuffered::getBuffer
char * getBuffer()
Get a pointer to the buffer.
Definition BucketBuffered.h:87
casacore::BucketBuffered::~BucketBuffered
virtual ~BucketBuffered()
casacore::BucketBuffered::itsBuffer
char * itsBuffer
Data buffer.
Definition BucketBuffered.h:119
casacore::BucketBuffered::BucketBuffered
BucketBuffered(BucketFile *file, Int64 startOffset, uInt bucketSize, uInt nrOfBuckets)
Create the object for (part of) a file.
casacore::BucketBuffered::doResync
virtual void doResync()
Do the actual resync-ing.
casacore::BucketBuffered::write
void write(uInt bucketNr, uInt bucketOffset, uInt nbytes)
Write the given part from the internal buffer.
casacore::BucketBuffered::BucketBuffered
BucketBuffered(const BucketBuffered &)
Copy constructor is not possible.
casacore::BucketBuffered::doExtend
virtual void doExtend(uInt nrBucket)
Extend the file with the given number of buckets.
casacore::BucketBuffered::read
void read(uInt bucketNr, uInt bucketOffset, uInt nbytes, uInt bufferOffset=0)
Read the given part into the internal buffer at the given offset.
casacore::BucketBuffered::initializeBuckets
virtual void initializeBuckets(uInt bucketNr)
Initialize the bucket buffer.
casacore::BucketBuffered::doFlush
virtual void doFlush()
Flush the file.
casacore::BucketFile
Definition BucketFile.h:105
casacore::FilebufIO
Definition FilebufIO.h:93
casacore
this file contains all the compiler specific defines
Definition mainpage.dox:28
casacore::uInt
unsigned int uInt
Definition aipstype.h:49
casacore::Int64
long long Int64
Define the extra non-standard types used by Casacore (like proposed uSize, Size).
Definition aipsxtype.h:36