TBranch.cxx

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// @(#)root/tree:$Id$
// Author: Rene Brun   12/01/96
 
/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
#include "TBranchCacheInfo.h"
 
#include "TBranch.h"
 
#include "Bytes.h"
#include "Compression.h"
#include "TBasket.h"
#include "TBranchBrowsable.h"
#include "TBrowser.h"
#include "TBuffer.h"
#include "TClass.h"
#include "TBufferFile.h"
#include "TClonesArray.h"
#include "TFile.h"
#include "TLeaf.h"
#include "TLeafB.h"
#include "TLeafC.h"
#include "TLeafD.h"
#include "TLeafD32.h"
#include "TLeafF.h"
#include "TLeafF16.h"
#include "TLeafI.h"
#include "TLeafL.h"
#include "TLeafG.h"
#include "TLeafO.h"
#include "TLeafObject.h"
#include "TLeafS.h"
#include "TMessage.h"
#include "TROOT.h"
#include "TSystem.h"
#include "TMath.h"
#include "TTree.h"
#include "TTreeCache.h"
#include "TTreeCacheUnzip.h"
#include "TVirtualMutex.h"
#include "TVirtualPad.h"
#include "TVirtualPerfStats.h"
#include "strlcpy.h"
#include "snprintf.h"
 
#include "TBranchIMTHelper.h"
 
#include "ROOT/TIOFeatures.hxx"
 
#include <atomic>
#include <cstddef>
#include <cstring>
#include <cstdio>
 
 
Int_t TBranch::fgCount = 0;
 
/** \class TBranch
\ingroup tree
 
A TTree is a list of TBranches
 
A TBranch supports:
 - The list of TLeaf describing this branch.
 - The list of TBasket (branch buffers).
 
See TBranch structure in TTree.
 
See also specialized branches:
 - TBranchObject in case the branch is one object
 - TBranchClones in case the branch is an array of clone objects
*/
 
 
 
 
////////////////////////////////////////////////////////////////////////////////
/// Default constructor.  Used for I/O by default.
 
TBranch::TBranch()
: TNamed()
, TAttFill(0, 1001)
, fCompress(0)
, fBasketSize(32000)
, fEntryOffsetLen(1000)
, fWriteBasket(0)
, fEntryNumber(0)
, fExtraBasket(nullptr)
, fOffset(0)
, fMaxBaskets(10)
, fNBaskets(0)
, fSplitLevel(0)
, fNleaves(0)
, fReadBasket(0)
, fReadEntry(-1)
, fFirstBasketEntry(-1)
, fNextBasketEntry(-1)
, fCurrentBasket(nullptr)
, fEntries(0)
, fFirstEntry(0)
, fTotBytes(0)
, fZipBytes(0)
, fBranches()
, fLeaves()
, fBaskets(fMaxBaskets)
, fBasketBytes(nullptr)
, fBasketEntry(nullptr)
, fBasketSeek(nullptr)
, fTree(nullptr)
, fMother(nullptr)
, fParent(nullptr)
, fAddress(nullptr)
, fDirectory(nullptr)
, fFileName("")
, fEntryBuffer(nullptr)
, fTransientBuffer(nullptr)
, fBrowsables(nullptr)
, fBulk(*this)
, fSkipZip(false)
, fReadLeaves(&TBranch::ReadLeavesImpl)
, fFillLeaves(&TBranch::FillLeavesImpl)
{
   SetBit(TBranch::kDoNotUseBufferMap);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Create a Branch as a child of a Tree
///
///   * address is the address of the first item of a structure
///     or the address of a pointer to an object (see example in TTree.cxx).
///   * leaflist is the concatenation of all the variable names and types
///     separated by a colon character :
///     The variable name and the variable type are separated by a
///     slash (/). The variable type must be 1 character. (Characters
///     after the first are legal and will be appended to the visible
///     name of the leaf, but have no effect.) If no type is given, the
///     type of the variable is assumed to be the same as the previous
///     variable. If the first variable does not have a type, it is
///     assumed of type F by default. The list of currently supported
///     types is given below:
///        - `C` : a character string terminated by the 0 character
///        - `B` : an 8 bit signed integer (`Char_t`); Treated as a character when in an array.
///        - `b` : an 8 bit unsigned integer (`UChar_t`)
///        - `S` : a 16 bit signed integer (`Short_t`)
///        - `s` : a 16 bit unsigned integer (`UShort_t`)
///        - `I` : a 32 bit signed integer (`Int_t`)
///        - `i` : a 32 bit unsigned integer (`UInt_t`)
///        - `F` : a 32 bit floating point (`Float_t`)
///        - `f` : a 24 bit floating point with truncated mantissa (`Float16_t`)
///        - `D` : a 64 bit floating point (`Double_t`)
///        - `d` : a 24 bit truncated floating point (`Double32_t`)
///        - `L` : a 64 bit signed integer (`Long64_t`)
///        - `l` : a 64 bit unsigned integer (`ULong64_t`)
///        - `G` : a long signed integer (`Long_t`, which `sizeof` is platform dependent), stored as a 64 bit integer but usually held in memory as a 64 bit integer on 64 bit machines and 32 bit on 32 bit machines. Due to this difference, this data type is **not cross-platform**.
///        - `g` : a long unsigned integer (`ULong_t`, which `sizeof` is platform dependent), stored as a 64 bit unsigned integer but held in memory usually as a 64 bit integer on 64 bit machines and 32 bit on 32 bit machines. Due to this difference, this data type is **not cross-platform**.
///        - `O` : [the letter `o`, not a zero] a boolean (`bool`)
///
///     Arrays of values are supported with the following syntax:
///     - If leaf name has the form var[nelem], where nelem is alphanumeric, then
///          if nelem is a leaf name, it is used as the variable size of the array,
///          otherwise return 0.
///          The leaf referred to by nelem **MUST** be an int (/I),
///     - If leaf name has the form var[nelem], where nelem is a non-negative integers, then
///          it is used as the fixed size of the array.
///     - If leaf name has the form of a multi dimension array (e.g. var[nelem][nelem2])
///          where nelem and nelem2 are non-negative integers) then
///          it is used as a 2 dimensional array of fixed size.
///     - In case of the truncated floating point types (Float16_t and Double32_t) you can
///          furthermore specify the range in the style [xmin,xmax] or [xmin,xmax,nbits] after
///          the type character. See `TStreamerElement::GetRange()` for further information.
///     - Any of other form is not supported.
///
///    Note that the TTree will assume that all the item are contiguous in memory.
///    On some platform, this is not always true of the member of a struct or a class,
///    due to padding and alignment.  Sorting your data member in order of decreasing
///    sizeof usually leads to their being contiguous in memory.
///
///   * bufsize is the buffer size in bytes for this branch
///     The default value is 32000 bytes and should be ok for most cases.
///     You can specify a larger value (e.g. 256000) if your Tree is not split
///     and each entry is large (Megabytes)
///     A small value for bufsize is optimum if you intend to access
///     the entries in the Tree randomly and your Tree is in split mode.
///
///   See an example of a Branch definition in the TTree constructor.
///
///   Note that in case the data type is an object, this branch can contain
///   only this object.
///
///    Note that this function is invoked by TTree::Branch
 
TBranch::TBranch(TTree *tree, const char *name, void *address, const char *leaflist, Int_t basketsize, Int_t compress)
   : TNamed(name, leaflist)
, TAttFill(0, 1001)
, fCompress(compress)
, fBasketSize((basketsize < 100) ? 100 : basketsize)
, fEntryOffsetLen(0)
, fWriteBasket(0)
, fEntryNumber(0)
, fExtraBasket(nullptr)
, fIOFeatures(tree ? tree->GetIOFeatures().GetFeatures() : 0)
, fOffset(0)
, fMaxBaskets(10)
, fNBaskets(0)
, fSplitLevel(0)
, fNleaves(0)
, fReadBasket(0)
, fReadEntry(-1)
, fFirstBasketEntry(-1)
, fNextBasketEntry(-1)
, fCurrentBasket(nullptr)
, fEntries(0)
, fFirstEntry(0)
, fTotBytes(0)
, fZipBytes(0)
, fBranches()
, fLeaves()
, fBaskets(fMaxBaskets)
, fBasketBytes(nullptr)
, fBasketEntry(nullptr)
, fBasketSeek(nullptr)
, fTree(tree)
, fMother(nullptr)
, fParent(nullptr)
, fAddress((char *)address)
, fDirectory(fTree->GetDirectory())
, fFileName("")
, fEntryBuffer(nullptr)
, fTransientBuffer(nullptr)
, fBrowsables(nullptr)
, fBulk(*this)
, fSkipZip(false)
, fReadLeaves(&TBranch::ReadLeavesImpl)
, fFillLeaves(&TBranch::FillLeavesImpl)
{
   Init(name,leaflist,compress);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Create a Branch as a child of another Branch
///
/// See documentation for
/// TBranch::TBranch(TTree *, const char *, void *, const char *, Int_t, Int_t)
 
TBranch::TBranch(TBranch *parent, const char *name, void *address, const char *leaflist, Int_t basketsize,
                 Int_t compress)
: TNamed(name, leaflist)
, TAttFill(0, 1001)
, fCompress(compress)
, fBasketSize((basketsize < 100) ? 100 : basketsize)
, fEntryOffsetLen(0)
, fWriteBasket(0)
, fEntryNumber(0)
, fExtraBasket(nullptr)
, fIOFeatures(parent->fIOFeatures)
, fOffset(0)
, fMaxBaskets(10)
, fNBaskets(0)
, fSplitLevel(0)
, fNleaves(0)
, fReadBasket(0)
, fReadEntry(-1)
, fFirstBasketEntry(-1)
, fNextBasketEntry(-1)
, fCurrentBasket(nullptr)
, fEntries(0)
, fFirstEntry(0)
, fTotBytes(0)
, fZipBytes(0)
, fBranches()
, fLeaves()
, fBaskets(fMaxBaskets)
, fBasketBytes(nullptr)
, fBasketEntry(nullptr)
, fBasketSeek(nullptr)
, fTree(parent ? parent->GetTree() : nullptr)
, fMother(parent ? parent->GetMother() : nullptr)
, fParent(parent)
, fAddress((char *)address)
, fDirectory(fTree ? fTree->GetDirectory() : nullptr)
, fFileName("")
, fEntryBuffer(nullptr)
, fTransientBuffer(nullptr)
, fBrowsables(nullptr)
, fBulk(*this)
, fSkipZip(false)
, fReadLeaves(&TBranch::ReadLeavesImpl)
, fFillLeaves(&TBranch::FillLeavesImpl)
{
   Init(name,leaflist,compress);
}
 
void TBranch::Init(const char* name, const char* leaflist, Int_t compress)
{
   // Initialization routine called from the constructor.  This should NOT be made virtual.
 
   SetBit(TBranch::kDoNotUseBufferMap);
   if ((compress == -1) && fTree->GetDirectory()) {
      TFile* bfile = fTree->GetDirectory()->GetFile();
      if (bfile) {
         fCompress = bfile->GetCompressionSettings();
      }
   }
 
   fBasketBytes = new Int_t[fMaxBaskets];
   fBasketEntry = new Long64_t[fMaxBaskets];
   fBasketSeek  = new Long64_t[fMaxBaskets];
 
   for (Int_t i = 0; i < fMaxBaskets; ++i) {
      fBasketBytes[i] = 0;
      fBasketEntry[i] = 0;
      fBasketSeek[i] = 0;
   }
 
   //
   // Decode the leaflist (search for : as separator).
   //
 
   char* nameBegin = const_cast<char*>(leaflist);
   Int_t offset = 0;
   auto len = strlen(leaflist);
   // FIXME: Make these string streams instead.
   char* leafname = new char[len + 1];
   char* leaftype = new char[320];
   // Note: The default leaf type is a float.
   strlcpy(leaftype, "F",320);
   char* pos = const_cast<char*>(leaflist);
   const char* leaflistEnd = leaflist + len;
   for (; pos <= leaflistEnd; ++pos) {
      // -- Scan leaf specification and create leaves.
      if ((*pos == ':') || (*pos == 0)) {
         // -- Reached end of a leaf spec, create a leaf.
         Int_t lenName = pos - nameBegin;
         char* ctype = nullptr;
         if (lenName) {
            strncpy(leafname, nameBegin, lenName);
            leafname[lenName] = 0;
            ctype = strstr(leafname, "/");
            if (ctype) {
               *ctype = 0;
               strlcpy(leaftype, ctype + 1,320);
            }
         }
         if (lenName == 0 || ctype == leafname) {
            Warning("TBranch","No name was given to the leaf number '%d' in the leaflist of the branch '%s'.",fNleaves,name);
            snprintf(leafname, len + 1, "__noname%d", fNleaves);
         }
         TLeaf* leaf = nullptr;
         if (leaftype[1] == '[' && !strchr(leaftype, ',')) {
            Warning("TBranch", "Array size for branch '%s' must be specified after leaf name, not after the type name!", name);
            // and continue for backward compatibility?
          } else if (leaftype[1] && !strchr(leaftype, ',')) {
            Warning("TBranch", "Extra characters after type tag '%s' for branch '%s'; must be one character.", leaftype, name);
            // and continue for backward compatibility?
         }
         if (*leaftype == 'C') {
            leaf = new TLeafC(this, leafname, leaftype);
         } else if (*leaftype == 'O') {
            leaf = new TLeafO(this, leafname, leaftype);
         } else if (*leaftype == 'B') {
            leaf = new TLeafB(this, leafname, leaftype);
         } else if (*leaftype == 'b') {
            leaf = new TLeafB(this, leafname, leaftype);
            leaf->SetUnsigned();
         } else if (*leaftype == 'S') {
            leaf = new TLeafS(this, leafname, leaftype);
         } else if (*leaftype == 's') {
            leaf = new TLeafS(this, leafname, leaftype);
            leaf->SetUnsigned();
         } else if (*leaftype == 'I') {
            leaf = new TLeafI(this, leafname, leaftype);
         } else if (*leaftype == 'i') {
            leaf = new TLeafI(this, leafname, leaftype);
            leaf->SetUnsigned();
         } else if (*leaftype == 'F') {
            leaf = new TLeafF(this, leafname, leaftype);
         } else if (*leaftype == 'f') {
            leaf = new TLeafF16(this, leafname, leaftype);
         } else if (*leaftype == 'L') {
            leaf = new TLeafL(this, leafname, leaftype);
         } else if (*leaftype == 'l') {
            leaf = new TLeafL(this, leafname, leaftype);
            leaf->SetUnsigned();
         } else if (*leaftype == 'D') {
            leaf = new TLeafD(this, leafname, leaftype);
         } else if (*leaftype == 'd') {
            leaf = new TLeafD32(this, leafname, leaftype);
         } else if (*leaftype == 'G') {
            leaf = new TLeafG(this, leafname, leaftype);
         } else if (*leaftype == 'g') {
            leaf = new TLeafG(this, leafname, leaftype);
            leaf->SetUnsigned();
         }
         if (!leaf) {
            Error("TLeaf", "Illegal data type for %s/%s", name, leaflist);
            delete[] leaftype;
            delete [] leafname;
            MakeZombie();
            return;
         }
         if (leaf->IsZombie()) {
            delete leaf;
            leaf = nullptr;
            auto msg = "Illegal leaf: %s/%s. If this is a variable size C array it's possible that the branch holding the size is not available.";
            Error("TBranch", msg, name, leaflist);
            delete [] leafname;
            delete[] leaftype;
            MakeZombie();
            return;
         }
         leaf->SetBranch(this);
         leaf->SetAddress((char*) (fAddress + offset));
         leaf->SetOffset(offset);
         if (leaf->GetLeafCount()) {
            // -- Leaf is a varying length array, we need an offset array.
            fEntryOffsetLen = 1000;
         }
         if (leaf->InheritsFrom(TLeafC::Class())) {
            // -- Leaf is a character string, we need an offset array.
            fEntryOffsetLen = 1000;
         }
         ++fNleaves;
         fLeaves.Add(leaf);
         fTree->GetListOfLeaves()->Add(leaf);
         if (*pos == 0) {
            // -- We reached the end of the leaf specification.
            break;
         }
         nameBegin = pos + 1;
         offset += leaf->GetLenType() * leaf->GetLen();
      }
   }
   delete[] leafname;
   leafname = nullptr;
   delete[] leaftype;
   leaftype = nullptr;
 
}
 
////////////////////////////////////////////////////////////////////////////////
/// Destructor.
 
TBranch::~TBranch()
{
   delete fBrowsables;
   fBrowsables = nullptr;
 
   // Note: We do *not* have ownership of the buffer.
   fEntryBuffer = nullptr;
 
   delete [] fBasketSeek;
   fBasketSeek  = nullptr;
 
   delete [] fBasketEntry;
   fBasketEntry = nullptr;
 
   delete [] fBasketBytes;
   fBasketBytes = nullptr;
 
   if (fExtraBasket && !fBaskets.Remove(fExtraBasket))
      delete fExtraBasket;
   fBaskets.Delete();
   fNBaskets = 0;
   fCurrentBasket = nullptr;
   fFirstBasketEntry = -1;
   fNextBasketEntry = -1;
 
   // Remove our leaves from our tree's list of leaves.
   if (fTree) {
      TObjArray* lst = fTree->GetListOfLeaves();
      if (lst && lst->GetLast()!=-1) {
         lst->RemoveAll(&fLeaves);
      }
   }
   // And delete our leaves.
   fLeaves.Delete();
 
   fBranches.Delete();
 
   // If we are in a directory and that directory is not the same
   // directory that our tree is in, then try to find an open file
   // with the name fFileName.  If we find one, delete that file.
   // We are attempting to close any alternate file which we have
   // been directed to write our baskets to.
   // FIXME: We make no attempt to check if someone else might be
   //        using this file.  This is very user hostile.  A violation
   //        of the principle of least surprises.
   //
   // Warning. Must use FindObject by name instead of fDirectory->GetFile()
   // because two branches may point to the same file and the file
   // may have already been deleted in the previous branch.
   if (fDirectory && (!fTree || fDirectory != fTree->GetDirectory())) {
      TString bFileName( GetRealFileName() );
 
      R__LOCKGUARD(gROOTMutex);
      TFile* file = (TFile*)gROOT->GetListOfFiles()->FindObject(bFileName);
      if (file){
         file->Close();
         delete file;
         file = nullptr;
      }
   }
 
   fTree = nullptr;
   fDirectory = nullptr;
 
   if (fTransientBuffer) {
      delete fTransientBuffer;
      fTransientBuffer = nullptr;
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Returns the transient buffer currently used by this TBranch for reading/writing baskets.
 
TBuffer* TBranch::GetTransientBuffer(Int_t size)
{
   if (fTransientBuffer) {
      if (fTransientBuffer->BufferSize() < size) {
         fTransientBuffer->Expand(size);
      }
      return fTransientBuffer;
   }
   fTransientBuffer = new TBufferFile(TBuffer::kRead, size);
   return fTransientBuffer;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add the basket to this branch.
///
/// Warning: if the basket are not 'flushed/copied' in the same
/// order as they were created, this will induce a slow down in
/// the insert (since we'll need to move all the record that are
/// entere 'too early').
/// Warning we also assume that the __current__ write basket is
/// not present (aka has been removed) or is empty (no entries).
 
void TBranch::AddBasket(TBasket& b, bool ondisk, Long64_t startEntry)
{
   TBasket *basket = &b;
 
   basket->SetBranch(this);
 
   if (fWriteBasket >= fMaxBaskets) {
      ExpandBasketArrays();
   }
   Int_t where = fWriteBasket;
 
   if (where && startEntry < fBasketEntry[where-1]) {
      // Need to find the right location and move the possible baskets
 
      if (!ondisk) {
         Warning("AddBasket","The assumption that out-of-order basket only comes from disk based ntuple is false.");
      }
 
      if (startEntry < fBasketEntry[0]) {
         where = 0;
      } else {
         for(Int_t i=fWriteBasket-1; i>=0; --i) {
            if (fBasketEntry[i] < startEntry) {
               where = i+1;
               break;
            } else if (fBasketEntry[i] == startEntry) {
               Error("AddBasket","An out-of-order basket matches the entry number of an existing basket.");
            }
         }
      }
 
      if (where < fWriteBasket) {
         // We shall move the content of the array
         for (Int_t j=fWriteBasket; j > where; --j) {
            fBasketEntry[j] = fBasketEntry[j-1];
            fBasketBytes[j] = fBasketBytes[j-1];
            fBasketSeek[j]  = fBasketSeek[j-1];
         }
      }
   }
   fBasketEntry[where] = startEntry;
 
   TBasket *existing = (TBasket*)fBaskets.At(fWriteBasket);
   if (existing && existing->GetNevBuf()) {
      Fatal("AddBasket", "Dropping non-empty 'write' basket in %s %s",
            GetTree()->GetName(), GetName());
   }
   delete existing;
   if (ondisk) {
      fBasketBytes[where] = basket->GetNbytes();  // not for in mem
      fBasketSeek[where] = basket->GetSeekKey();  // not for in mem
      fBaskets.AddAtAndExpand(nullptr, fWriteBasket);
      ++fWriteBasket;
   } else {
      ++fNBaskets;
      // The basket we are adding becomes the new 'write' basket.
      fBaskets.AddAtAndExpand(basket,fWriteBasket);
      fTree->IncrementTotalBuffers(basket->GetBufferSize());
   }
 
   fEntries += basket->GetNevBuf();
   fEntryNumber += basket->GetNevBuf();
   if (ondisk) {
      fTotBytes += basket->GetObjlen() + basket->GetKeylen() ;
      fZipBytes += basket->GetNbytes();
      fTree->AddTotBytes(basket->GetObjlen() + basket->GetKeylen());
      fTree->AddZipBytes(basket->GetNbytes());
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add the start entry of the write basket (not yet created)
 
void TBranch::AddLastBasket(Long64_t startEntry)
{
   if (fWriteBasket >= fMaxBaskets) {
      ExpandBasketArrays();
   }
   Int_t where = fWriteBasket;
 
   if (where && startEntry < fBasketEntry[where-1]) {
      // Need to find the right location and move the possible baskets
 
      Fatal("AddBasket","The last basket must have the highest entry number (%s/%lld/%d).",GetName(),startEntry,fWriteBasket);
 
   }
   // The first basket (should) always start at zero. If we are asked to update
   // it, this likely to be from merging 'empty' branches (base class node and the likes)
   if (where) {
      fBasketEntry[where] = startEntry;
      fBaskets.AddAtAndExpand(nullptr,fWriteBasket);
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Loop on all leaves of this branch to back fill Basket buffer.
///
/// Use this routine instead of TBranch::Fill when filling a branch individually
/// to catch up with the number of entries already in the TTree.
///
/// First it calls TBranch::Fill and then if the number of entries of the branch
/// reach one of TTree cluster's boundary, the basket is flushed.
///
/// The function returns the number of bytes committed to the memory basket.
/// If a write error occurs, the number of bytes returned is -1.
/// If no data are written, because e.g. the branch is disabled,
/// the number of bytes returned is 0.
///
/// To insure that the baskets of each cluster are located close by in the
/// file, when back-filling multiple branches make sure to call BackFill
/// for the same entry for all the branches consecutively
/// ~~~ {.cpp}
///   for( auto e = 0; e < tree->GetEntries(); ++e ) { // loop over entries.
///     for( auto branch : branchCollection) {
///        ... Make change to the data associated with the branch ...
///        branch->BackFill();
///     }
///   }
///   // Since we loop over all the branches for each new entry
///   // all the baskets for a cluster are consecutive in the file.
/// ~~~
/// rather than doing all the entries of one branch at a time.
/// ~~~ {.cpp}
///   // Do NOT do things in the following order, it will lead to
///   // poorly clustered files.
///   for(auto branch : branchCollection) {
///     for( auto e = 0; e < tree->GetEntries(); ++e ) { // loop over entries.
///        ... Make change to the data associated with the branch ...
///        branch->BackFill();
///     }
///   }
///   // Since we loop over all the entries for one branch
///   // all the baskets for that branch are consecutive.
/// ~~~
 
Int_t TBranch::BackFill() {
 
   // Get the end of the next cluster.
   auto cluster  = GetTree()->GetClusterIterator( GetEntries() );
   cluster.Next();
   auto endCluster = cluster.GetNextEntry();
 
   auto result = FillImpl(nullptr);
 
   if ( result && GetEntries() >= endCluster ) {
      FlushBaskets();
   }
 
   return result;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Browser interface.
 
void TBranch::Browse(TBrowser* b)
{
   if (fNleaves > 1) {
      fLeaves.Browse(b);
   } else {
      // Get the name and strip any extra brackets
      // in order to get the full arrays.
      TString name = GetName();
      Int_t pos = name.First('[');
      if (pos!=kNPOS) name.Remove(pos);
 
      GetTree()->Draw(name, "", b ? b->GetDrawOption() : "");
      if (gPad) gPad->Update();
   }
}
 
 ///////////////////////////////////////////////////////////////////////////////
 /// Loop on all branch baskets. If the file where branch buffers reside is
 /// writable, free the disk space associated to the baskets of the branch,
 /// then call Reset(). If the option contains "all", delete also the baskets
 /// for the subbranches.
 /// The branch is reset.
 ///
 /// NOTE that this function must be used with extreme care. Deleting branch baskets
 /// fragments the file and may introduce inefficiencies when adding new entries
 /// in the Tree or later on when reading the Tree.
 
void TBranch::DeleteBaskets(Option_t* option)
{
   TString opt = option;
   opt.ToLower();
   TFile *file = GetFile(0);
 
   if(fDirectory && (fDirectory != gROOT) && fDirectory->IsWritable()) {
      for(Int_t i=0; i<fWriteBasket; i++) {
         if (fBasketSeek[i]) file->MakeFree(fBasketSeek[i],fBasketSeek[i]+fBasketBytes[i]-1);