ChainSlice

Description

Wrapper around TChain that restricts available entries to a subset.

This class acts like a TChain, with the additional feature of limiting the available entries to a subset of the original. The first entry that will be used is set with SetBeginEntry, and the last one with SetEndEntry. Once set, a normal iteration through the chain (with SetEntry or similar) will be restricted to entries in [begin, end).

In essence, a ChainSlice behaves like iterating on a normal chain from GetBegin (inclusive) to GetEnd (exclusive).

Note

Adding friends to a ChainSlice is untested. \bugs Calling LoadTree() directly will not work as expected.

#include <FriendUtils.h>

Inheritance diagram for ChainSlice:

Collaboration diagram for ChainSlice:

Public Member Functions
	ChainSlice (const ChainSlice &)=delete
	ChainSlice (Long64_t begin=0, Long64_t end=-1)
	ChainSlice (const char *name, Long64_t begin=0, Long64_t end=-1, const char *title="")
virtual	~ChainSlice ()
Long64_t	GetBegin () const
Long64_t	GetEnd () const
void	SetBegin (Long64_t begin)
void	SetEnd (Long64_t end)
Long64_t	GetEntries () const override
Long64_t	GetEntriesFast () const override
Int_t	GetEntry (Long64_t entry, Int_t getall=0) override
Long64_t	GetReadEntry () const override
Long64_t	GetReadEvent () const override
Long64_t	LoadTreeFriend (Long64_t entry, TTree *parent) override
	ChainSlice (const ChainSlice &)=delete
	ChainSlice (Long64_t begin=0, Long64_t end=-1)
	ChainSlice (const char *name, Long64_t begin=0, Long64_t end=-1, const char *title="")
virtual	~ChainSlice ()
Long64_t	GetBegin () const
Long64_t	GetEnd () const
void	SetBegin (Long64_t begin)
void	SetEnd (Long64_t end)
Long64_t	GetEntries () const override
Long64_t	GetEntriesFast () const override
Int_t	GetEntry (Long64_t entry, Int_t getall=0) override
Long64_t	GetReadEntry () const override
Long64_t	GetReadEvent () const override
Long64_t	LoadTreeFriend (Long64_t entry, TTree *parent) override

Private Member Functions
auto	GetLast () const
auto	GetLast () const

Private Attributes
Long64_t	fBegin
Long64_t	fEnd

Constructor & Destructor Documentation

ChainSlice() [1/6]

ChainSlice ( const ChainSlice &  )

delete

ChainSlice() [2/6]

ChainSlice ( Long64_t  begin = 0, Long64_t  end = -1  )

inline

Creates a ChainSlice.

The first and last entries can optionally be provided.

        : fBegin(begin)
        , fEnd(end)
    {
        // Force creation of the friends list. This controls friend handling in
        // TChain::LoadTree, *also for the friends of the loaded TTree*. I
        // consider this a bug in ROOT.
        fFriends = new TList();
    }

ChainSlice() [3/6]

ChainSlice ( const char *  name, Long64_t  begin = 0, Long64_t  end = -1, const char *  title = ""  )

inline

Creates a ChainSlice.

The first and last entries can optionally be provided. See the TChain constructor for other arguments.

        : TChain(name, title)
        , fBegin(begin)
        , fEnd(end)
    {
        // Force creation of the friends list. This controls friend handling in
        // TChain::LoadTree, *also for the friends of the loaded TTree*. I
        // consider this a bug in ROOT.
        fFriends = new TList();
    }

~ChainSlice() [1/2]

~ChainSlice ( )

virtual

Destructor.

{}

ChainSlice() [4/6]

ChainSlice ( const ChainSlice &  )

delete

ChainSlice() [5/6]

ChainSlice ( Long64_t  begin = 0, Long64_t  end = -1  )

inline

Creates a ChainSlice.

The first and last entries can optionally be provided.

        : fBegin(begin)
        , fEnd(end)
    {
        // Force creation of the friends list. This controls friend handling in
        // TChain::LoadTree, *also for the friends of the loaded TTree*. I
        // consider this a bug in ROOT.
        fFriends = new TList();
    }

ChainSlice() [6/6]

ChainSlice ( const char *  name, Long64_t  begin = 0, Long64_t  end = -1, const char *  title = ""  )

inline

Creates a ChainSlice.

The first and last entries can optionally be provided. See the TChain constructor for other arguments.

        : TChain(name, title)
        , fBegin(begin)
        , fEnd(end)
    {
        // Force creation of the friends list. This controls friend handling in
        // TChain::LoadTree, *also for the friends of the loaded TTree*. I
        // consider this a bug in ROOT.
        fFriends = new TList();
    }

~ChainSlice() [2/2]

virtual ~ChainSlice ( )

virtual

Member Function Documentation

GetBegin() [1/2]

Long64_t GetBegin ( ) const

inline

Returns the index of the first entry that will be used.

{ return fBegin; }

GetBegin() [2/2]

Long64_t GetBegin ( ) const

inline

Returns the index of the first entry that will be used.

{ return fBegin; }

GetEnd() [1/2]

Long64_t GetEnd ( ) const

inline

Returns the index past the last entry that will be used.

{ return fEnd; }

GetEnd() [2/2]

Long64_t GetEnd ( ) const

inline

Returns the index past the last entry that will be used.

{ return fEnd; }

GetEntries() [1/2]

Long64_t GetEntries ( ) const

inlineoverride

Return the total number of entries in the chain, taking the restrictions set by GetBegin and GetEnd into account.

{ return GetLast() - GetBegin(); }

GetEntries() [2/2]

Long64_t GetEntries ( ) const

inlineoverride

Return the total number of entries in the chain, taking the restrictions set by GetBegin and GetEnd into account.

{ return GetLast() - GetBegin(); }

GetEntriesFast() [1/2]

Long64_t GetEntriesFast ( ) const

inlineoverride

Return the total number of entries in the chain, taking the restrictions set by begin and end into account.

Synomym for GetEntries.

{ return GetEntries(); }

GetEntriesFast() [2/2]

Long64_t GetEntriesFast ( ) const

inlineoverride

Return the total number of entries in the chain, taking the restrictions set by begin and end into account.

Synomym for GetEntries.

{ return GetEntries(); }

GetEntry() [1/2]

Int_t GetEntry ( Long64_t  entry, Int_t  getall = 0  )

inlineoverride

Get entry from the chain to memory.

Todo:

description

See TChain::GetEntry for details.

    { return TChain::GetEntry(entry + GetBegin(), getall); }

GetEntry() [2/2]

Int_t GetEntry ( Long64_t  entry, Int_t  getall = 0  )

inlineoverride

Get entry from the chain to memory.

Todo:

description

See TChain::GetEntry for details.

    { return TChain::GetEntry(entry + GetBegin(), getall); }

GetLast() [1/2]

auto GetLast ( ) const

inlineprivate

Returns the last entry to load, taking negative fEnd into account.

    {
        return fEnd >= 0 ? std::min(fEnd, TChain::GetEntries())
                         : TChain::GetEntries();
    }

GetLast() [2/2]

auto GetLast ( ) const

inlineprivate

Returns the last entry to load, taking negative fEnd into account.

    {
        return fEnd >= 0 ? std::min(fEnd, TChain::GetEntries())
                         : TChain::GetEntries();
    }

GetReadEntry() [1/2]

Long64_t GetReadEntry ( ) const

inlineoverride

Number of the currently-loaded entry.

This override takes GetBegin into account.

{ return TChain::GetReadEntry() - GetBegin(); }

GetReadEntry() [2/2]

Long64_t GetReadEntry ( ) const

inlineoverride

Number of the currently-loaded entry.

This override takes GetBegin into account.

{ return TChain::GetReadEntry() - GetBegin(); }

GetReadEvent() [1/2]

Long64_t GetReadEvent ( ) const

inlineoverride

Number of the currently-loaded entry.

This override takes GetBegin into account.

{ return GetReadEntry(); }

GetReadEvent() [2/2]

Long64_t GetReadEvent ( ) const

inlineoverride

Number of the currently-loaded entry.

This override takes GetBegin into account.

{ return GetReadEntry(); }

LoadTreeFriend() [1/2]

Long64_t LoadTreeFriend ( Long64_t  entry, TTree *  parent  )

inlineoverride

Loads the requested entry, called from a friend tree.

This override takes GetBegin into account.

    { return TChain::LoadTreeFriend(entry + GetBegin(), parent); }

LoadTreeFriend() [2/2]

Long64_t LoadTreeFriend ( Long64_t  entry, TTree *  parent  )

inlineoverride

Loads the requested entry, called from a friend tree.

This override takes GetBegin into account.

    { return TChain::LoadTreeFriend(entry + GetBegin(), parent); }

SetBegin() [1/2]

void SetBegin ( Long64_t  begin )

inline

Changes the first entry to be loaded.

The currently loaded entry is not modified.

{ fBegin = begin; }

SetBegin() [2/2]

void SetBegin ( Long64_t  begin )

inline

Changes the first entry to be loaded.

The currently loaded entry is not modified.

{ fBegin = begin; }

SetEnd() [1/2]

void SetEnd ( Long64_t  end )

inline

Changes the last entry to be loaded.

The currently loaded entry is not modified.

{ fEnd = end; }

SetEnd() [2/2]

void SetEnd ( Long64_t  end )

inline

Changes the last entry to be loaded.

The currently loaded entry is not modified.

{ fEnd = end; }

Member Data Documentation

fBegin

Long64_t fBegin

private

The first entry to use.

fEnd

Long64_t fEnd

private

Past the last entry to use, or -1 to go till the end.

---

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

• /builds/cms-analysis/general/DasAnalysisSystem/Core/Installer/Darwin/interface/FriendUtils.h
• /builds/cms-analysis/general/DasAnalysisSystem/Core/Installer/Darwin/src/FriendUtils.cc