fire::io::Writer Class Reference

Write the fire DataSets into a deterministic structure in the output HDF5 data file. More...

#include <Writer.h>

Collaboration diagram for fire::io::Writer:

Classes
class	Buffer
	Buffer atomic data types in-memory for efficient disk operations. More...
class	BufferHandle
	Type-less handle to buffers. More...

Public Member Functions
	Writer (const int &event_limit, const config::Parameters &ps)
	Open the file in write mode. More...
	~Writer ()
	Close up our file, making sure to flush contents to disk.
void	flush ()
	Flush the data to disk. More...
const std::string &	name () const
	Get the name of this file.
void	structure (const std::string &path, const std::pair< std::string, int > &type)
	Persist the structure of the event object at the input path. More...
std::size_t	entries () const
	Get the number of entries in the file.
template<typename AtomicType >
void	save (const std::string &path, const AtomicType &val)
	Save an atomic type into the dataset at the passed path. More...
	Writer (const Writer &)=delete
	don't allow copies of the Writer
void	operator= (const Writer &)=delete
	don't allow copies of the Writer

Private Attributes
std::unique_ptr< HighFive::File >	file_
	our highfive file More...
HighFive::DataSetCreateProps	create_props_
	the creation properties to be used on datasets we are writing
HighFive::DataSpace	space_
	the dataspace shared amongst all of our datasets
std::size_t	entries_
	the expected number of entries in this file
std::size_t	rows_per_chunk_
	number of rows to keep in each chunk
std::unordered_map< std::string, std::unique_ptr< BufferHandle > >	buffers_
	our in-memory buffers for data to be written to disk

Friends
std::ostream &	operator<< (std::ostream &s, const Writer &w)
	Stream this writer. More...

Detailed Description

Write the fire DataSets into a deterministic structure in the output HDF5 data file.

See also

h5::Reader for where our files are read

Constructor & Destructor Documentation

Writer()

fire::io::Writer::Writer	(	const int &	event_limit,
		const config::Parameters &	ps
	)

Open the file in write mode.

Our write mode is the HDF5 TRUNC (overwrite) mode.

Parameters

[in]	event_limit	Maximum number of events that could end up here
[in]	ps	Parameters used to configure the writing of the output file

Member Function Documentation

flush()

void fire::io::Writer::flush

(

)

Flush the data to disk.

We flush all buffers and then flush the file.

save()

template<typename AtomicType >

void fire::io::Writer::save ( const std::string &  path, const AtomicType &  val  )

inline

Save an atomic type into the dataset at the passed path.

If the path does not have a Buffer created for it yet, we create a new one. Creating this new buffer is when HDF5 creates the DataSet in the file and so it may throw an exception at this time if it is unable to create the DataSet for some reason.

If the path already has a Buffer, we simply pass the new value to be saved into the Buffer.

Exceptions

std::bad_cast	if mismatched type is passed to buffer
HighFive::DataSetException	if unable to create data set

structure()

void fire::io::Writer::structure	(	const std::string &	path,
		const std::pair< std::string, int > &	type
	)

Persist the structure of the event object at the input path.

The "structure" is simply the type and the type's version at the correct location within the EVENT_GROUP.

Note

The save method creates the DataSets so this method should only be called on levels of the hierarchy that DO NOT correspond to HDF5 data sets.

Parameters

[in]	path	full path to the group
[in]	{type,version}	pair demangled type name of object and its version number
[in]	version	version number of type

Friends And Related Function Documentation

operator<<

std::ostream & operator<< ( std::ostream &  s, const Writer &  w  )

friend

Stream this writer.

We stream 'Writer' and the name of the file we are writing to

Parameters

[in]	s	ostream to stream into
[in]	w	writer to stream

Returns

modified ostream

Member Data Documentation

file_

std::unique_ptr<HighFive::File> fire::io::Writer::file_

private

our highfive file

we need it to be a smart pointer because we want to do some parameter validation before creating the file in the constructor

---

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

• include/fire/io/Writer.h
• src/fire/io/Writer.cxx