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Reference Guide
TEntryListFromFile.h
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1 // @(#)root/tree:$Id$
2 // Author: Anna Kreshuk 17/03/2007
3 
4 /*************************************************************************
5  * Copyright (C) 1995-2007, Rene Brun and Fons Rademakers. *
6  * All rights reserved. *
7  * *
8  * For the licensing terms see $ROOTSYS/LICENSE. *
9  * For the list of contributors see $ROOTSYS/README/CREDITS. *
10  *************************************************************************/
11 
12 #ifndef ROOT_TEntryListFromFile
13 #define ROOT_TEntryListFromFile
14 
15 //////////////////////////////////////////////////////////////////////////
16 // TEntryListFromFile
17 //
18 // Manages entry lists from different files, when they are not loaded
19 // in memory at the same time.
20 //
21 // This entry list should only be used when processing a TChain (see
22 // TChain::SetEntryList() function). File naming convention:
23 // - by default, filename_elist.root is used, where filename is the
24 // name of the chain element.
25 // - xxx$xxx.root - $ sign is replaced by the name of the chain element
26 // If the list name is not specified (by passing filename_elist.root/listname to
27 // the TChain::SetEntryList() function, the first object of class TEntryList
28 // in the file is taken.
29 // It is assumed that there are as many lists, as there are chain elements,
30 // and they are in the same order.
31 //
32 // If one of the list files can't be opened, or there is an error reading a list
33 // from the file, this list is skipped and the entry loop continues on the next
34 // list.
35 
36 #include "TEntryList.h"
37 
38 class TFile;
39 
41 {
42 protected:
43  TString fListFileName; ///< from this string names of all files can be found
44  TString fListName; ///< name of the list
45  Int_t fNFiles; ///< total number of files
46  Long64_t *fListOffset; ///<[fNFiles] numbers of entries in ind. lists
47  TFile *fFile; ///< currently open file
48  ///< fCurrent points to the currently open list
49  TObjArray *fFileNames; ///<! points to the fFiles data member of the corresponding chain
50 
51  // Obsolete use TTree::kMaxEntries
52  static constexpr auto kBigNumber = std::numeric_limits<Long64_t>::max();
53 
54 private:
55  TEntryListFromFile(const TEntryListFromFile&); // Not implemented.
56  TEntryListFromFile &operator=(const TEntryListFromFile&); // Not implemented.
57 
58 public:
59 
61  TEntryListFromFile(const char *filename, const char *listname, Int_t nfiles);
62  virtual ~TEntryListFromFile();
63  virtual void Add(const TEntryList * /*elist*/){};
64  virtual Int_t Contains(Long64_t /*entry*/, TTree * /*tree = 0*/) {return 0;};
65  virtual Bool_t Enter(Long64_t /*entry*/, TTree * /*tree = 0*/){return 0;};
66  virtual TEntryList *GetCurrentList() const { return fCurrent; };
67  virtual TEntryList *GetEntryList(const char * /*treename*/, const char * /*filename*/, Option_t * /*opt=""*/) {return 0;};
68 
69  virtual Long64_t GetEntry(Int_t index);
70  virtual Long64_t GetEntryAndTree(Int_t index, Int_t &treenum);
71  virtual Long64_t GetEntries();
72  virtual Long64_t GetEntriesFast() const { return fN; };
73 
74  virtual Long64_t GetN() const { return fN; }
75  virtual const char *GetTreeName() const { return fTreeName.Data(); }
76  virtual const char *GetFileName() const { return fFileName.Data(); }
77  virtual Int_t GetTreeNumber() const { return fTreeNumber; }
78 
79  virtual Int_t LoadList(Int_t listnumber);
80 
81  virtual Int_t Merge(TCollection * /*list*/){ return 0; };
82 
83  virtual Long64_t Next();
84  virtual void OptimizeStorage() {};
85  virtual Bool_t Remove(Long64_t /*entry*/, TTree * /*tree = 0*/){ return 0; };
86 
87  virtual void Print(const Option_t* option = "") const;
88 
89  virtual void SetTree(const TTree * /*tree*/){};
90  virtual void SetTree(const char * /*treename*/, const char * /*filename*/){};
91  virtual void SetFileNames(TObjArray *names) { fFileNames = names; }
92  virtual void SetTreeNumber(Int_t index) { fTreeNumber=index; }
93  virtual void SetNFiles(Int_t nfiles) { fNFiles = nfiles; }
94  virtual void Subtract(const TEntryList * /*elist*/) {};
95 
96  ClassDef(TEntryListFromFile, 1); //Manager for entry lists from different files
97 };
98 #endif
virtual Long64_t GetEntriesFast() const
TString fListName
name of the list
An array of TObjects.
Definition: TObjArray.h:37
long long Long64_t
Definition: RtypesCore.h:69
Manages entry lists from different files, when they are not loaded in memory at the same time...
TString fListFileName
from this string names of all files can be found
const char Option_t
Definition: RtypesCore.h:62
virtual void SetTree(const char *, const char *)
If a list for a tree with such name and filename exists, sets it as the current sublist If not...
virtual Bool_t Enter(Long64_t, TTree *)
Add entry #entry to the list.
TObjArray * fFileNames
! points to the fFiles data member of the corresponding chain
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format...
Definition: TFile.h:48
Basic string class.
Definition: TString.h:131
Int_t fNFiles
total number of files
int Int_t
Definition: RtypesCore.h:41
bool Bool_t
Definition: RtypesCore.h:59
virtual Int_t Contains(Long64_t, TTree *)
virtual Int_t Merge(TCollection *)
Merge this list with the lists from the collection.
static constexpr auto kBigNumber
virtual void OptimizeStorage()
Checks if the array representation is more economical and if so, switches to it.
#define ClassDef(name, id)
Definition: Rtypes.h:326
TFile * fFile
currently open file fCurrent points to the currently open list
virtual void Print(const Option_t *option="") const
Print info about this list.
virtual void SetNFiles(Int_t nfiles)
virtual Int_t LoadList(Int_t listnumber)
Loads the list #listnumber This is the only function that can modify fCurrent and fFile data members...
virtual Long64_t Next()
Returns the next entry in the list.
TString fTreeName
name of the tree
Definition: TEntryList.h:38
virtual Long64_t GetEntry(Int_t index)
Returns entry #index See also Next() for a faster alternative.
TEntryListFromFile & operator=(const TEntryListFromFile &)
virtual void Add(const TEntryList *)
Add 2 entry lists.
virtual TEntryList * GetEntryList(const char *, const char *, Option_t *)
Return the entry list, corresponding to treename and filename By default, the filename is first tried...
TEntryList * fCurrent
! currently filled entry list
Definition: TEntryList.h:32
Collection abstract base class.
Definition: TCollection.h:63
virtual Bool_t Remove(Long64_t, TTree *)
Remove entry #entry from the list.
virtual void Subtract(const TEntryList *)
Remove all the entries of this entry list, that are contained in elist.
virtual ~TEntryListFromFile()
d-tor
Long64_t fN
number of entries in the list
Definition: TEntryList.h:36
virtual const char * GetTreeName() const
virtual void SetTreeNumber(Int_t index)
virtual const char * GetFileName() const
virtual Long64_t GetN() const
Long64_t * fListOffset
[fNFiles] numbers of entries in ind. lists
Int_t fTreeNumber
! the index of the tree in the chain (used when the entry list is used as input (TTree::SetEntryList(...
Definition: TEntryList.h:41
virtual Long64_t GetEntries()
Returns the total number of entries in the list.
virtual Long64_t GetEntryAndTree(Int_t index, Int_t &treenum)
Return the entry corresponding to the index parameter and the number of the tree, where this entry is...
virtual Int_t GetTreeNumber() const
virtual void SetTree(const TTree *)
If a list for a tree with such name and filename exists, sets it as the current sublist If not...
A TTree represents a columnar dataset.
Definition: TTree.h:72
TString fFileName
name of the file, where the tree is
Definition: TEntryList.h:39
A List of entry numbers in a TTree or TChain.
Definition: TEntryList.h:25
virtual void SetFileNames(TObjArray *names)
virtual TEntryList * GetCurrentList() const
const char * Data() const
Definition: TString.h:364