library: libTable
#include "TFileIter.h"

TFileIter

class description - header file - source file
viewCVS header - viewCVS source

class TFileIter: public TListIter

Inheritance Inherited Members Includes Libraries
Class Charts

Function Members (Methods)

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public:
TFileIter(TFile* file = 0)
TFileIter(const TFileIter&)
TFileIter(const char* name, Option_t* option = "", const char* ftitle = "", Int_t compress = 1, Int_t netopt = 0)
virtual~TFileIter()
static TClass*Class()
Int_tCurrentCursorPosition() const
virtual const TCollection*TListIter::GetCollection() const
TKey*GetCurrentKey() const
static const char*GetDefaultMapFileName()
static const char*GetForeignFileSystemKey()
const char*GetKeyName() const
static const char*GetLocalFileNameKey()
virtual TObject*GetObject() const
Int_tGetObjlen() const
virtual Option_t*TListIter::GetOption() const
static const char*GetResourceName()
virtual const TFile*GetTFile() const
virtual TClass*IsA() const
static TStringMapName(const char* name, const char* localSystemKey = "0", const char* mountedFileSystemKey = "0")
virtual TObject*Next()
virtual TObject*Next(Int_t nSkip)
virtual TObject*NextEventGet(UInt_t eventNumber = UInt_t(-1), UInt_t runNumber = UInt_t(-1), const char* name = "*")
virtual Int_tNextEventPut(TObject* obj, UInt_t eventNum, UInt_t runNumber, const char* name = "0")
char*operator const char*() const
TFile*operator const TFile*() const
intoperator int() const
intoperator!=(const char* name) const
TObject*operator()()
TObject*operator()(Int_t nSkip)
TObject*operator*() const
TFileIter&operator++()
TFileIter&operator+=(Int_t shift)
TFileIter&operator--()
TFileIter&operator-=(Int_t shift)
TFileIter&operator=(Int_t cursorPosition)
TFileIter&operator=(const char* keyNameToFind)
intoperator==(const char* name) const
virtual voidReset()
virtual voidRewind()
voidSetCursorPosition(Int_t cursorPosition)
voidSetCursorPosition(const char* keyNameToFind)
voidTListIter::SetOption(Option_t* option)
virtual voidShowMembers(TMemberInspector& insp, char* parent)
virtual TObject*SkipObjects(Int_t nSkip = 1)
virtual voidStreamer(TBuffer& b)
voidStreamerNVirtual(TBuffer& b)
virtual Int_tTotalKeys() const
protected:
voidInitialize()
TKey*NextEventKey(UInt_t eventNumber = UInt_t(-1), UInt_t runNumber = UInt_t(-1), const char* name = "*")
TObject*ReadObj(const TKey* key) const
voidRestoreFileScope()
voidSaveFileScope()
private:
virtual TIterator&operator=(const TIterator&)

Data Members

protected:
TFile*fRootFileTfile to be iterated over
TStringfEventNamecurrent key name
UInt_tfRunNumbercurrent "run number"
UInt_tfEventNumbercurrent "event number"
Int_tfCursorPositionthe position of the current key in the sorted TKey list
Bool_tfOwnTFileBit whether this classs creates TFile on its own to delete
const TList*TListIter::fListlist being iterated
TObjLink*TListIter::fCurCursorcurrent position in list
TObjLink*TListIter::fCursornext position in list
Bool_tTListIter::fDirectioniteration direction
Bool_tTListIter::fStartediteration started
private:
TFile*fFileBackUp! temporary data-members
TDirectory*fDirectoryBackUp! to save/restore TFile/TDirectory global scope

Class Description

                                                                       
 Class to iterate (read / write ) the events written to TFile.         
 The event is supposed to assign an unique ID in form of               
                                                                       
  TKey <event Id> ::= eventName "." run_number "." event_number        
                                                                       
 and stored as the TKey name of the object written                     
                                                                       
        ///////        //////////      ////////        ///////     

 void TestFileIter(){
 // This macros tests the various methods of TFileIter class.
   gSystem->Load("libTable");

   //First create simple ROOT file
   TDataSet *ds = new TDataSet("event");
   TObject *nextObject = 0;
   TRandom run;
   TRandom event;
   {
     TFileIter outSet("test.root","RECREATE");
     UInt_t totalEvent = 10;
     UInt_t runNumber  = 20010301;
     Int_t i=0;
     Int_t j=0;
     for (;j < 10;j++) {
       for (i = 1;i<totalEvent;i++) {
         outSet.NextEventPut(ds,UInt_t(i),UInt_t(runNumber+j+10*run.Rndm()-5));
       }
     }
   }
   printf(" ----------------------> TFile has been created <--------------------\n");
   TFile *f = new TFile("test.root");
   TFileIter readObj(f);
   // the number of the object available directly from "MyDataSet.root"
   Int_t size = readObj.TotalKeys();
   printf(" The total number of the objects: %d\n",size);

   //-----------------------------------------------------------------------
   // Loop over all objects, read them in to memory one by one

   printf(" -- > Loop over all objects, read them in to memory one by one < -- \n");
   for( readObj = 0; int(readObj) < size; ++readObj){
       nextObject = *readObj;
       printf(" %d bytes of the object \"%s\" of class \"%s\" written with TKey \"%s\"  has been read from file\n"
                ,readObj.GetObjlen()
                ,nextObject->GetName()
                ,nextObject->IsA()->GetName()
                ,(const char *)readObj
             );
       delete nextObject;
  }
 //-----------------------------------------------------------------------
 //  Now loop over all objects in inverse order
  printf(" -- > Now loop over all objects in inverse order < -- \n");
  for( readObj = size-1; (int)readObj >= 0; --readObj)
  {
       nextObject = *readObj;
       if (nextObject) {
          printf(" Object \"%s\" of class \"%s\" written with TKey \"%s\"  has been read from file\n"
                 ,nextObject->GetName()
                 , nextObject->IsA()->GetName()
                 ,(const char *)readObj
                );
         delete nextObject;
      } else {
        printf("Error reading file by index\n");
      }
  }
 //-----------------------------------------------------------------------
 // Loop over the objects starting from the object with the key name "event.02.01"
   printf(" -- > Loop over the objects starting from the object with the key name \"event.02.01\" < -- \n");
   for( readObj = "event.02.01"; (const char *)readObj != 0; ++readObj){
       nextObject = *readObj;
       printf(" Object \"%s\" of class \"%s\" written with Tkey \"%s\"  has been read from file\n"
               , nextObject->GetName()
               , nextObject->IsA()->GetName()
               , (const char *)readObj
             );
       delete nextObject;
   }

   printf(" -- > Loop over the objects starting from the 86-th object" < -- \n");
   for( readObj = (const char *)(readObj = 86); (const char *)readObj != 0; ++readObj){
       nextObject = *readObj;
       printf(" Object \"%s\" of class \"%s\" written with Tkey \"%s\"  has been read from file\n"
               , nextObject->GetName()
               , nextObject->IsA()->GetName()
               , (const char *)readObj
             );
       delete nextObject;
   }

 }
-----------------------------------------------------------------------
TFileIter(TFile *file)
to be documented
TFileIter(const char *name, Option_t *option, const char *ftitle , Int_t compress, Int_t /*netopt*/)
 Open ROOT TFile by the name provided;
 This TFile is to be deleted by the TFileIter alone
TFileIter(const TFileIter &dst)
 Copy stor can be used with the "read only" files only.
~TFileIter()
to be documented
void Initialize()
to be documented
TKey * GetCurrentKey()
 return the pointer to the current TKey
const char * GetKeyName()
 return the name of the current TKey
TObject * GetObject()
 read the object from TFile defined by the current TKey

 ATTENTION:  memory leak danger !!!
 ---------
 This method does create a new object and it is the end-user
 code responsibility to take care about the object returned
 to avoid memeory leak.
Int_t GetObjlen()
 Returns the uncompressed length of the current object
Int_t TotalKeys()
 The total number of the TKey keys in this current TFile
 Usually this means the total number of different objects
 thos can be read separately with one "read" operation
TObject * Next(Int_t nSkip)
 return the pointer to the object defined by next TKey
 This method is not recommended. It was done for the sake
 of the compatibility with TListIter
void Reset()
 Reset the status of the iterator
void SetCursorPosition(const char *keyNameToFind)
 Find the key by the name provided
TObject * SkipObjects(Int_t nSkip)
 Returns the pointer to the nSkip object from the current one
 nSkip = 0; the state of the iterator is not changed

 nSkip > 0; iterator skips nSkip objects in the container.
            the direction of the iteration is
            sign(nSkip)*kIterForward
TKey * NextEventKey(UInt_t eventNumber, UInt_t runNumber, const char *name)
TObject * NextEventGet(UInt_t eventNumber, UInt_t runNumber, const char *name)
 reads, creates and returns the object by TKey name that matches
 the "name" ."runNumber" ." eventNumber" schema
 Attention: This method does create a new TObject and it is the user
 code responsibility to take care (delete) this object to avoid
 memory leak.
TObject * ReadObj(const TKey *key)
to be documented
Int_t NextEventPut(TObject *obj, UInt_t eventNum, UInt_t runNumber , const char *name)
 Create a special TKey name with obj provided and write it out.
TString MapName(const char *name, const char *localSystemKey,const char *mountedFileSystemKey)
 --------------------------------------------------------------------------------------
 MapName(const char *name, const char *localSystemKey,const char *mountedFileSystemKey)
 --------------------------------------------------------------------------------------
 Substitute the logical name with the real one if any
 1. add a line into system.rootrc or ~/.rootrc or ./.rootrc

  TFileIter.ForeignFileMap  mapFile // the name of the file
 to map the local name
 to the global file service

  If this line is omitted then TFileIter class seeks for
  the default mapping file in the current directory "io.config"
const char * GetResourceName()
__________________________________________________________________________
__________________________________________________________________________
{return "ForeignFileMap";}
const char * GetDefaultMapFileName()
__________________________________________________________________________
{return "io.config";}
const char * GetLocalFileNameKey()
__________________________________________________________________________
{return "LocalFileSystem";}
const char * GetForeignFileSystemKey()
{return "MountedFileSystem";}
Int_t CurrentCursorPosition()
__________________________________________________________________________
 return the current
const TFile * GetTFile()
__________________________________________________________________________
{ return fRootFile; }
TObject * Next()
__________________________________________________________________________
 Make 1 step over the file objects and returns its pointer
 or 0, if there is no object left in the container
void Rewind()
__________________________________________________________________________
void SetCursorPosition(Int_t cursorPosition)
__________________________________________________________________________
 Make <cursorPosition> steps (>0 - forward) over the file
 objects to skip it
TFileIter & operator=(const char *keyNameToFind)
__________________________________________________________________________
 Iterate unless the name of the object matches <keyNameToFind>
TFileIter & operator=(Int_t cursorPosition)
__________________________________________________________________________
 Iterate over <cursorPosition>
TFileIter & operator+=(Int_t shift)
__________________________________________________________________________
__________________________________________________________________________
{ SkipObjects(shift); return *this;}
TFileIter & operator-=(Int_t shift)
__________________________________________________________________________
{ return operator+=(-shift);}
TFileIter & operator++()
__________________________________________________________________________
{ SkipObjects( 1); return *this;}
TFileIter & operator--()
__________________________________________________________________________
{ SkipObjects(-1); return *this;}
TObject * operator*()
__________________________________________________________________________
{ return GetObject();}
int operator==(const char *name)
__________________________________________________________________________
{ return name ? !strcmp(name,GetKeyName()):0;}
int operator!=(const char *name)
__________________________________________________________________________
{ return !(operator==(name)); }
TObject * operator()()
__________________________________________________________________________
__________________________________________________________________________
{ return Next(); }
TObject * operator()(Int_t nSkip)
{ return Next(nSkip);}
void SaveFileScope()
__________________________________________________________________________
{ fFileBackUp = gFile; fDirectoryBackUp = gDirectory; }
void RestoreFileScope()
__________________________________________________________________________
{ gFile = fFileBackUp; gDirectory = fDirectoryBackUp; }
TIterator & operator=(const TIterator &)
{ return *this; }

Author: Valery Fine(fine@bnl.gov) 01/03/2001
Last update: root/table:$Name: $:$Id: TFileIter.cxx,v 1.6 2006/05/21 18:05:26 brun Exp $
Copyright (C) 1995-2004, Rene Brun and Fons Rademakers. *

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