soma::ItemReader< T > Class Template Reference

Low-level "small item" reader, used by higher-level file readers. More...

#include <soma-io/reader/itemreader.h>

Inheritance diagram for soma::ItemReader< T >:

Public Member Functions
virtual	~ItemReader ()
virtual ItemReader< T > *	reader (bool binary=true, bool bswap=false) const =0
	Factory function. More...
virtual long	read (DataSource &ds, T *pitem, size_t n=1) const =0
	Reading on an arbitrary DataSource. More...

Detailed Description

template<typename T>
class soma::ItemReader< T >

Low-level "small item" reader, used by higher-level file readers.

It can read either a single item, or an array of them. This template class is inherited by specific item readers, esp. by the DefaultItemReader classes.

Usage: you generally have to allocate two readers: one as a factory to use the correct item variant, and another one to switch on the reading-mode specific ItemReader:

#include <soma-io/reader/defaultitemreader.h>
using namespace soma;
// Let's read a vector of signed 16 bits elements
short                     shortarray[ 100 ];
DefaultItemReader<short>  ir1;
bool                      binary;
bool                      bswap;

// get binary and bswap from the header of the file to read
// ...
// now we assume it's done

ItemReader<short>       *ir = ir1.reader( binary, bswap );
// we use ir in the following, we can forget ir1 now.

FileDataSource  ds( "file.dat" );
if( !ds.open( DataSource::Read ) )
  return false; // fail
// read 100 elements
ir->read( ds, shortarray, 100 );
// don't forget to destroy the reader after use
// (or put it in a scoped_ptr)
delete ir;

Definition at line 84 of file itemreader.h.

Constructor & Destructor Documentation

~ItemReader()

template<typename T>

virtual soma::ItemReader< T >::~ItemReader ( )

inlinevirtual

Definition at line 87 of file itemreader.h.

References soma::ItemReader< T >::read(), and soma::ItemReader< T >::reader().

Member Function Documentation

read()

template<typename T>

virtual long soma::ItemReader< T >::read ( DataSource &  ds, T *  pitem, size_t  n = 1  ) const

pure virtual

Reading on an arbitrary DataSource.

Parameters

ds	source of data (file, buffer, socket...)
pitem	buffer to fill with read values
n	number of elements to read

Returns

number of elements actually read

Implemented in soma::DefaultBSwapItemReader< T >, soma::DefaultAsciiItemReader< T >, and soma::DefaultItemReader< T >.

Referenced by soma::DefaultAsciiItemReader< T >::~DefaultAsciiItemReader(), soma::DefaultBSwapItemReader< T >::~DefaultBSwapItemReader(), soma::DefaultItemReader< T >::~DefaultItemReader(), and soma::ItemReader< T >::~ItemReader().

reader()

template<typename T>

virtual ItemReader<T>* soma::ItemReader< T >::reader ( bool  binary = true, bool  bswap = false  ) const

pure virtual

Factory function.

Implemented in soma::DefaultItemReader< T >, soma::DefaultItemReader< T >, and soma::DefaultItemReader< T >.

Referenced by soma::DefaultItemReader< T >::~DefaultItemReader(), and soma::ItemReader< T >::~ItemReader().

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

• soma-io/reader/itemreader.h