TNL::File Class Reference

This class serves for binary IO. It allows to do IO even for data allocated on GPU together with on-the-fly data type conversion. More...

#include <TNL/File.h>

Collaboration diagram for TNL::File:

Public Member Functions
	File ()=default
	Basic constructor.
	File (const File &)=delete
	File (const std::string &fileName, std::ios_base::openmode mode=std::ios_base::in|std::ios_base::out)
	Constructor which opens given file.
	File (File &&)=default
void	close ()
	Closes the file.
const std::string &	getFileName () const
	Returns name of the file.
template<typename SourceType >
void	ignore (std::streamsize elements=1)
	Extracts and discards characters from the file.
template<typename Type , typename SourceType = Type, typename Allocator = Allocators::Host< Type >>
void	load (Type *destination, std::streamsize elements=1)
	Method for loading data from the file.
void	open (const std::string &fileName, std::ios_base::openmode mode=std::ios_base::in|std::ios_base::out)
	Open given file.
File &	operator= (const File &)=delete
File &	operator= (File &&)=default
template<typename Type , typename TargetType = Type, typename Allocator = Allocators::Host< Type >>
void	save (const Type *source, std::streamsize elements=1)
	Method for saving data to the file.

Protected Member Functions
template<typename Type , typename SourceType , typename Allocator , typename = std::enable_if_t< allocates_host_accessible_data_v< Allocator > >>
void	load_impl (Type *destination, std::streamsize elements)
template<typename Type , typename SourceType , typename Allocator , typename = std::enable_if_t< ! allocates_host_accessible_data_v< Allocator > >, typename = void>
void	load_impl (Type *destination, std::streamsize elements)
template<typename Type , typename TargetType , typename Allocator , typename = std::enable_if_t< allocates_host_accessible_data_v< Allocator > >>
void	save_impl (const Type *source, std::streamsize elements)
template<typename Type , typename TargetType , typename Allocator , typename = std::enable_if_t< ! allocates_host_accessible_data_v< Allocator > >, typename = void>
void	save_impl (const Type *source, std::streamsize elements)

Protected Attributes
std::fstream	file
std::string	fileName

Detailed Description

This class serves for binary IO. It allows to do IO even for data allocated on GPU together with on-the-fly data type conversion.

Example

#include <iostream>
#include <string>
 
#include <TNL/File.h>
 
using namespace TNL;
 
int main()
{
    File file;
 
    file.open( std::string("new-file.tnl"), std::ios_base::out );
    std::string title("'string to file'");
    file << title;
    file.close();
 
    file.open( std::string("new-file.tnl"), std::ios_base::in );
    std::string restoredString;
    file >> restoredString;
    file.close();
 
    std::cout << "restored string = " << restoredString << std::endl;
}

Output

restored string = 'string to file'

Constructor & Destructor Documentation

File()

TNL::File::File ( const std::string &  fileName, std::ios_base::openmode  mode = std::ios_base::in | std::ios_base::out  )

inline

Constructor which opens given file.

All parameters are passed to the open method.

Member Function Documentation

close()

void TNL::File::close ( )

inline

Closes the file.

Throws std::ios_base::failure on failure.

ignore()

template<typename SourceType >

void TNL::File::ignore

(

std::streamsize

elements = 1

)

Extracts and discards characters from the file.

Throws std::ios_base::failure on failure.

Template Parameters

SourceType

type of data stored on the file,

Parameters

elements

number of elements to be read and ignored.

load()

template<typename Type , typename SourceType , typename Allocator >

void TNL::File::load	(	Type *	destination,
		std::streamsize	elements = 1
	)

Method for loading data from the file.

The data will be stored in buffer which was allocated using the allocator of type Allocator. The data type of the buffer is given by the template parameter Type. The second template parameter SourceType defines the type of data in the source file. If both types are different, on-the-fly conversion takes place during the data loading.

Throws std::ios_base::failure on failure.

Template Parameters

Type	type of data to be loaded to the destination.
SourceType	type of data stored on the file,
Allocator	type of the allocator which was used to allocate destination.

Parameters

destination	Pointer in memory where the elements are loaded and stored after reading.
elements	number of elements to be loaded from the file.

The following example shows how to load data directly to GPU.

Example

#include <iostream>
#include <TNL/File.h>
#include <TNL/Allocators/Cuda.h>
 
using namespace TNL;
 
int main()
{
   const int size = 3;
   double doubleArray[] = {  3.1415926535897932384626433,
                             2.7182818284590452353602874,
                             1.6180339887498948482045868 };
 
   /***
    * Save array to file.
    */
   File file;
   file.open( "file-example-cuda-test-file.tnl", std::ios_base::out | std::ios_base::trunc );
   file.save< double, double, Allocators::Host< double > >( doubleArray, size );
   file.close();
 
   /***
    * Allocate arrays on host and device
    */
   double *deviceArray, *hostArray;
   cudaMalloc( ( void** ) &deviceArray, size * sizeof( double ) );
   hostArray = new double[ 3 ];
 
   /***
    * Read array from the file to device
    */
   file.open( "file-example-cuda-test-file.tnl", std::ios_base::in );
   file.load< double, double, Allocators::Cuda< double > >( deviceArray, size );
   file.close();
 
   /***
    * Copy array from device to host
    */
   cudaMemcpy( ( void* ) hostArray, ( const void* ) deviceArray, size * sizeof( double), cudaMemcpyDeviceToHost );
 
   /***
    * Print the array on host
    */
   std::cout.precision( 15 );
   for( int i = 0; i < size; i++ )
      std::cout << hostArray[ i ] << std::endl;
 
   /***
    * Free allocated memory
    */
   cudaFree( deviceArray );
   delete[] hostArray;
}

Output

3.14159265358979
2.71828182845905
1.61803398874989

The following example shows how to do on-the-fly data conversion.

Example

#include <iostream>
#include <TNL/File.h>
 
using namespace TNL;
 
int main()
{
   const int size = 3;
   double doubleArray[] = {  3.1415926535897932384626433,
                             2.7182818284590452353602874,
                             1.6180339887498948482045868 };
   float floatArray[ 3 ];
   int intArray[ 3 ];
 
   /***
    * Save the array of doubles as floats.
    */
   File file;
   file.open( "test-file.tnl", std::ios_base::out | std::ios_base::trunc );
   file.save< double, float >( doubleArray, size );
   file.close();
 
   /***
    * Load the array of floats from the file.
    */
   file.open( "test-file.tnl", std::ios_base::in );
   file.load< float, float >( floatArray, size );
   file.close();
 
   /***
    * Load the array of floats from the file and convert them to integers.
    */
   file.open( "test-file.tnl", std::ios_base::in );
   file.load< int, float >( intArray, size );
   file.close();
 
   /***
    * Print all arrays.
    */
   std::cout.precision( 15 );
   for( int i = 0; i < size; i++ )
      std::cout << doubleArray[ i ] << " -- "
                << floatArray[ i ] << " -- "
                << intArray[ i ] << std::endl;
}

Output

3.14159265358979 -- 3.14159274101257 -- 3
2.71828182845905 -- 2.71828174591064 -- 2
1.61803398874989 -- 1.6180340051651 -- 1

open()

void TNL::File::open ( const std::string &  fileName, std::ios_base::openmode  mode = std::ios_base::in | std::ios_base::out  )

inline

Open given file.

Opens file with given fileName in some mode from std::ios_base::openmode. Note that the file is always opened in binary mode, i.e. std::ios_base::binary is always added to mode.

Throws std::ios_base::failure on failure.

Parameters

fileName	String which indicates file name.
mode	Indicates in what mode the file will be opened - see std::ios_base::openmode.

save()

template<typename Type , typename TargetType , typename Allocator >

void TNL::File::save	(	const Type *	source,
		std::streamsize	elements = 1
	)

Method for saving data to the file.

The data from the buffer (with type Type) which was allocated using an allocator of type Allocator. TargetType defines as what data type the buffer shall be saved. If the type is different from the data type, on-the-fly data type conversion takes place during the data saving.

Throws std::ios_base::failure on failure.

Template Parameters

Type	type of data in the source.
TargetType	tells as what type data the buffer shall be saved.
Allocator	type of the allocator which was used to allocate source.
Index	type of index by which the elements are indexed.

Parameters

source	buffer that is going to be saved to the file.
elements	number of elements saved to the file.

See File::load for examples.

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

• src/TNL/File.h
• src/TNL/File.hpp