Reading ROOT files into our data structures. More...

#include <Reader.h>

Inheritance diagram for fire::io::root::Reader:

Collaboration diagram for fire::io::root::Reader:

Public Member Functions
	Reader (const std::string &file_name)
	open input file for reading More...

virtual void	load_into (BaseData &d) final override
	Following the instructions in fire::io::Reader, we simply call the BaseData's load function. More...

virtual std::vector< std::pair< std::string, std::string > >	availableObjects () final override
	Get the event objects available in the file. More...

virtual std::pair< std::string, int >	type (const std::string &path) final override
	Get the type of the input object. More...

virtual std::string	name () const final override
	Get the name of the file. More...

virtual std::size_t	entries () const final override
	Number of entries in the file. More...

virtual std::size_t	runs () const final override
	Number of runs in the file. More...

template<typename DataType >
void	load (const std::string &name, DataType &obj)
	Load the data at the input name into the input object. More...

	Reader (const Reader &)=delete
	no copy constructor of readers

void	operator= (const Reader &)=delete
	no copy assignment of readers

Public Member Functions inherited from fire::io::Reader
	Reader (const std::string &file_name)
	open the file at the passed location More...

virtual	~Reader ()=default
	virtual destructor so derived classes can be closed

virtual bool	canCopy () const
	Event::get needs to know if the reader implements a copy that advances the entry index of the data sets being read. More...

virtual void	copy (long unsigned int i_entry, const std::string &path, Writer &output)
	Copy the input object into the output file. More...

Private Member Functions
template<typename T >
TBranch *	attach (TTree *tree, const std::string &branch_name, T &obj)
	Attach the input object to the TTree on the given branch. More...

Static Private Member Functions
static std::string	transform (const std::string &dir_name)
	pull out pass and object name, construct branch name More...

Private Attributes
TFile *	file_
	file being read

TTree *	event_tree_
	tree of events in the file

TTree *	run_tree_
	tree of runs in the file

std::map< std::string, TBranch * >	attached_

Additional Inherited Members
Public Types inherited from fire::io::Reader
using	Factory = ::fire::factory::Factory< Reader, std::unique_ptr< Reader >, const std::string & >
	Type of factory used to create readers.

Detailed Description

Reading ROOT files into our data structures.

If you are familiar with the ROOT-based Framework, this Reader effectively does tasks done by the framework::Event and framework::EventFile classes.

Constructor & Destructor Documentation

◆ Reader()

fire::io::root::Reader::Reader ( const std::string & file_name )

open input file for reading

Exceptions

Exception if file cannot be opened, a TTree named 'LDMX_Events' is not found, or if a TTree named 'LDMX_Run' is not found.

After opening the file and retrieve the TTrees we will read, we turn off ROOT's "feature" of handling standard Unix signals.

Parameters

[in] file_name file to open with ROOT

Member Function Documentation

◆ attach()

template<typename T >

TBranch * fire::io::root::Reader::attach	(	TTree *	tree,
		const std::string &	branch_name,
		T &	obj
	)

inlineprivate

Attach the input object to the TTree on the given branch.

Exceptions

Exception if branch cannot be found.

If the type is arithmetic (numeric_limits are specialized for it), then we use the SetAddress function for attaching to the branch; otherwise, we can use the SetObject method.

Template Parameters

T	type of object to attach

Parameters

[in]	tree	TTree to attach to
[in]	branch_name	name of branch to attach to
[in]	obj	reference to object to attach

Returns: pointer to branch that we attached to

◆ availableObjects()

std::vector< std::pair< std::string, std::string > > fire::io::root::Reader::availableObjects ( )

finaloverridevirtual

Get the event objects available in the file.

We loop through the branches of the event TTree and parse their type names, object name, and pass name. We skip the branch named "EventHeader" to achieve the same behavior as h5::Reader.

Returns: vector of string pairs { obj_name, pass }

Implements fire::io::Reader.

◆ entries()

std::size_t fire::io::root::Reader::entries ( ) const

finaloverridevirtual

Number of entries in the file.

We get this from the number of entries in the event ttree.

Returns: number of entries in the file

Implements fire::io::Reader.

◆ load()

template<typename DataType >

void fire::io::root::Reader::load	(	const std::string &	name,
		DataType &	obj
	)

inline

Load the data at the input name into the input object.

See also: transform for how we get the ROOT branch name from the input HDF5-style nested group names.

We choose the tree from the deduced branch name. If the branch name is "RunHeader", the we use the run tree ; otherwise, the event tree.

If the branch name isn't found in our 'attached_' map, then we use attach to attempt to attach it.

At the end, we load the data into memory using TBranch GetReadEntry to retrieve the current entry and increment it before providing it back to GetEntry.

Template Parameters

DataType type of data to load into

Parameters

[in]	name	name of data to load
[in]	obj	reference to load into

◆ load_into()

void fire::io::root::Reader::load_into ( BaseData & d )

finaloverridevirtual

Following the instructions in fire::io::Reader, we simply call the BaseData's load function.

Parameters

[in] d Data to load data into

Implements fire::io::Reader.

◆ name()

std::string fire::io::root::Reader::name ( ) const

finaloverridevirtual

Get the name of the file.

We use ROOT's TFile rather than storing the name of the file ourselves.

Returns: full name of file currently reading

Implements fire::io::Reader.

◆ runs()

std::size_t fire::io::root::Reader::runs ( ) const

finaloverridevirtual

Number of runs in the file.

We get this from the number of runs in the run ttree.

Returns: number of runs in the file

Implements fire::io::Reader.

◆ transform()

std::string fire::io::root::Reader::transform ( const std::string & dir_name )

staticprivate

pull out pass and object name, construct branch name

static caching map since this function is called so frequently

Parameters

[in] dir_name HDF5-style (<pass>/<object>) group name of event object

Returns: branch name in ROOT-framework-style (<object>_<pass>)

◆ type()

std::pair< std::string, int > fire::io::root::Reader::type ( const std::string & path )

finaloverridevirtual

Get the type of the input object.

Implements fire::io::Reader.

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

include/fire/io/root/Reader.h
src/fire/io/root/Reader.cxx

Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Reader()

Member Function Documentation

◆ attach()

◆ availableObjects()

◆ entries()

◆ load()

◆ load_into()

◆ name()

◆ runs()

◆ transform()

◆ type()