// @(#)root/tree:$Name:  $:$Id: TTreeIndex.cxx,v 1.7 2004/12/08 10:15:30 brun Exp $
// Author: Rene Brun   05/07/2004

/*************************************************************************
 * Copyright (C) 1995-2004, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

//////////////////////////////////////////////////////////////////////////
//                                                                      //
// A Tree Index with majorname and minorname.                           //
//                                                                      //
//////////////////////////////////////////////////////////////////////////

#include "TTreeIndex.h"
#include "TTree.h"

ClassImp(TTreeIndex)

//______________________________________________________________________________
 TTreeIndex::TTreeIndex(): TVirtualIndex()
{
// Default constructor for TTreeIndex

   fTree               = 0;
   fN                  = 0;
   fIndexValues        = 0;
   fIndex              = 0;
   fMajorFormula       = 0;
   fMinorFormula       = 0;
   fMajorFormulaParent = 0;
   fMinorFormulaParent = 0;
}

//______________________________________________________________________________
 TTreeIndex::TTreeIndex(const TTree *T, const char *majorname, const char *minorname)
           : TVirtualIndex()
{
   // Normal constructor for TTreeIndex
   //
   // Build an index table using the leaves of Tree T with  major & minor names
   // The index is built with the expressions given in "majorname" and "minorname".
   //
   // a Long64_t array fIndexValues is built with:
   //    major = the value of majorname converted to an integer
   //    minor = the value of minorname converted to an integer
   //    fIndexValues[i] = major<<31 + minor
   // This array is sorted. The sorted fIndex[i] contains the serial number
   // in the Tree corresponding to the pair "major,minor" in fIndexvalues[i].
   //
   //  Once the index is computed, one can retrieve one entry via
   //    T->GetEntryWithIndex(majornumber, minornumber)
   // Example:
   //  tree.BuildIndex("Run","Event"); //creates an index using leaves Run and Event
   //  tree.GetEntryWithIndex(1234,56789); //reads entry corresponding to
   //                                        Run=1234 and Event=56789
   //
   // Note that majorname and minorname may be expressions using original
   // Tree variables eg: "run-90000", "event +3*xx". However the result
   // must be integer.
   // In case an expression is specified, the equivalent expression must be computed
   // when calling GetEntryWithIndex.
   //
   // To build an index with only majorname, specify minorname="0" (default)
   //
   //    TreeIndex and Friend Trees
   //    ---------------------------
   // Assuming a parent Tree T and a friend Tree TF, the following cases are supported:
   // CASE 1: T->GetEntry(entry) is called
   //         In this case, the serial number entry is used to retrieve
   //         the data in both Trees.
   // CASE 2: T->GetEntry(entry) is called, TF has a TreeIndex
   //         the expressions given in major/minorname of TF are used
   //         to compute the value pair major,minor with the data in T.
   //         TF->GetEntry(major,minor) is then called (tricky case!)
   // CASE 3: T->GetEntry(major,minor) is called.
   //         It is assumed that both T and TF have a TreeIndex built using
   //         the same major and minor name.
   //
   //    Saving the TreeIndex
   //    --------------------
   // Once the index is built, it can be saved with the TTree object
   // with tree.Write(); (if the file has been open in "update" mode).
   //
   // The most convenient place to create the index is at the end of
   // the filling process just before saving the Tree header.
   // If a previous index was computed, it is redefined by this new call.
   //
   // Note that this function can also be applied to a TChain.
   //
   // The return value is the number of entries in the Index (< 0 indicates failure)
   //
   // It is possible to play with different TreeIndex in the same Tree.
   // see comments in TTree::SetTreeIndex.

   fTree               = (TTree*)T;
   fN                  = 0;
   fIndexValues        = 0;
   fIndex              = 0;
   fMajorFormula       = 0;
   fMinorFormula       = 0;
   fMajorFormulaParent = 0;
   fMinorFormulaParent = 0;
   fMajorName          = majorname;
   fMinorName          = minorname;
   if (!T) return;
   fN = (Long64_t)T->GetEntries();
   if (fN <= 0) {
      MakeZombie();
      Error("TreeIndex","Cannot build a TreeIndex with a Tree having no entries");
      return;
   }

   GetMajorFormula();
   GetMinorFormula();
   if (!fMajorFormula || !fMinorFormula) {
      MakeZombie();
      Error("TreeIndex","Cannot build the index with major=%s, minor=%s",fMajorName.Data(), fMinorName.Data());
      return;
   }
   if ((fMajorFormula->GetNdim() != 1) || (fMinorFormula->GetNdim() != 1)) {
      MakeZombie();
      Error("TreeIndex","Cannot build the index with major=%s, minor=%s",fMajorName.Data(), fMinorName.Data());
      return;
   }
   // accessing array elements should be OK
   //if ((fMajorFormula->GetMultiplicity() != 0) || (fMinorFormula->GetMultiplicity() != 0)) {
   //   MakeZombie();
   //   Error("TreeIndex","Cannot build the index with major=%s, minor=%s that cannot be arrays",fMajorName.Data(), fMinorName.Data());
   //   return;
   //}

   Long64_t *w = new Long64_t[fN];
   Long64_t i;
   for (i=0;i<fN;i++) {
      GetEntry(i);
      Double_t majord = fMajorFormula->EvalInstance();
      Double_t minord = fMinorFormula->EvalInstance();
      Long64_t majorv = (Long64_t)majord;
      Long64_t minorv = (Long64_t)minord;
      w[i]  = majorv<<31;
      w[i] += minorv;
   }
   fIndex = new Long64_t[fN];
   TMath::Sort(fN,w,fIndex,0);
   fIndexValues = new Long64_t[fN];
   for (i=0;i<fN;i++) {
      fIndexValues[i] = w[fIndex[i]];
   }

   delete [] w;
}

//______________________________________________________________________________
 TTreeIndex::~TTreeIndex()
{
   if (fTree && fTree->GetTreeIndex() == this) fTree->SetTreeIndex(0);
   delete [] fIndexValues;      fIndexValues = 0;
   delete [] fIndex;            fIndex = 0;
   delete fMajorFormula;        fMajorFormula  = 0;
   delete fMinorFormula;        fMinorFormula  = 0;
   delete fMajorFormulaParent;  fMajorFormulaParent = 0;
   delete fMinorFormulaParent;  fMinorFormulaParent = 0;
}

//______________________________________________________________________________
 Int_t TTreeIndex::GetEntry(Long64_t entry)
{
   // Read in memory the branches referenced in major and minorname

   if (!fTree) return 0;
   TLeaf *leaf;
   Int_t i;
   Int_t nbytes = 0;
   for (i=0;i<10;i++) {
      if (!fMajorFormula) break;
      leaf = fMajorFormula->GetLeaf(i);
      if (!leaf) break;
      nbytes += leaf->GetBranch()->GetEntry(entry);
   }
   for (i=0;i<10;i++) {
      if (!fMinorFormula) break;
      leaf = fMinorFormula->GetLeaf(i);
      if (!leaf) break;
      nbytes += leaf->GetBranch()->GetEntry(entry);
   }
   return nbytes;
}

//______________________________________________________________________________
 Int_t TTreeIndex::GetEntryNumberFriend(const TTree *T)
{
// returns the entry number in this friend Tree corresponding to entry in
// the master Tree T.
// In case this friend Tree and T do not share an index with the same
// major and minor name, the entry serial number in the friend tree
// and in the master Tree are assumed to be the same

   if (!T) return -3;
   GetMajorFormulaParent(T);
   GetMinorFormulaParent(T);
   if (!fMajorFormulaParent || !fMinorFormulaParent) return -1;
   if (!fMajorFormulaParent->GetNdim() || !fMinorFormulaParent->GetNdim()) {
      // The Tree Index in the friend has a pair majorname,minorname
      // not available in the parent Tree T.
      // if the friend Tree has less entries than the parent, this is an error
      Int_t pentry = T->GetReadEntry();
      if (pentry >= (Int_t)fTree->GetEntries()) return -2;
      // otherwise we ignore the Tree Index and return the entry number
      // in the parent Tree.
      return pentry;
   }

   // majorname, minorname exist in the parent Tree
   // we find the current values pair majorv,minorv in the parent Tree
   Double_t majord = fMajorFormulaParent->EvalInstance();
   Double_t minord = fMinorFormulaParent->EvalInstance();
   Long64_t majorv = (Long64_t)majord;
   Long64_t minorv = (Long64_t)minord;
   // we check if this pair exist in the index.
   // if yes, we return the corresponding entry number
   // if not the function returns -1
   return fTree->GetEntryNumberWithIndex(majorv,minorv);
}

//______________________________________________________________________________
 Long64_t TTreeIndex::GetEntryNumberWithBestIndex(Int_t major, Int_t minor) const
{
// Return entry number corresponding to major and minor number
// Note that this function returns only the entry number, not the data
// To read the data corresponding to an entry number, use TTree::GetEntryWithIndex
// the BuildIndex function has created a table of Double_t* of sorted values
// corresponding to val = major + minor*1e-9;
// The function performs binary search in this sorted table.
// If it finds a pair that maches val, it returns directly the
// index in the table.
// If an entry corresponding to major and minor is not found, the function
// returns the index of the major,minor pair immediatly lower than the
// requested value, ie it will return -1 if the pair is lower than
// the first entry in the index.
//
// See also GetEntryNumberWithIndex

   if (fN == 0) return -1;
   Long64_t value = Long64_t(major)<<31;
   value += minor;
   Int_t i = TMath::BinarySearch(fN, fIndexValues, value);
   if (i < 0) return -1;
   return fIndex[i];
}


//______________________________________________________________________________
 Long64_t TTreeIndex::GetEntryNumberWithIndex(Int_t major, Int_t minor) const
{
// Return entry number corresponding to major and minor number
// Note that this function returns only the entry number, not the data
// To read the data corresponding to an entry number, use TTree::GetEntryWithIndex
// the BuildIndex function has created a table of Double_t* of sorted values
// corresponding to val = major + minor*1e-9;
// The function performs binary search in this sorted table.
// If it finds a pair that maches val, it returns directly the
// index in the table, otherwise it returns -1.
//
// See also GetEntryNumberWithBestIndex

   if (fN == 0) return -1;
   Long64_t value = Long64_t(major)<<31;
   value += minor;
   Int_t i = TMath::BinarySearch(fN, fIndexValues, value);
   if (i < 0) return -1;
   if (TMath::Abs(fIndexValues[i] - value) > 1.e-10) return -1;
   return fIndex[i];
}

//______________________________________________________________________________
 TTreeFormula *TTreeIndex::GetMajorFormula()
{
   // return a pointer to the TreeFormula corresponding to the majorname

   if (!fMajorFormula) fMajorFormula = new TTreeFormula("Major",fMajorName.Data(),fTree);
   return fMajorFormula;
}

//______________________________________________________________________________
 TTreeFormula *TTreeIndex::GetMinorFormula()
{
   // return a pointer to the TreeFormula corresponding to the minorname

   if (!fMinorFormula) fMinorFormula = new TTreeFormula("Minor",fMinorName.Data(),fTree);
   return fMinorFormula;
}

//______________________________________________________________________________
 TTreeFormula *TTreeIndex::GetMajorFormulaParent(const TTree *T)
{
   // return a pointer to the TreeFormula corresponding to the majorname in parent tree T

   if (!fMajorFormulaParent) fMajorFormulaParent = new TTreeFormula("MajorP",fMajorName.Data(),(TTree*)T);
   return fMajorFormulaParent;
}

//______________________________________________________________________________
 TTreeFormula *TTreeIndex::GetMinorFormulaParent(const TTree *T)
{
   // return a pointer to the TreeFormula corresponding to the minorname in parent tree T

   if (!fMinorFormulaParent) fMinorFormulaParent = new TTreeFormula("MinorP",fMinorName.Data(),(TTree*)T);
   return fMinorFormulaParent;
}

//______________________________________________________________________________
 void TTreeIndex::Print(Option_t * option) const
{
   // print the table with : serial number, majorname, minorname
   // if option = "10" print only the first 10 entries
   // if option = "100" print only the first 100 entries
   // if option = "1000" print only the first 1000 entries

   TString opt = option;
   Long64_t n = fN;
   if (opt.Contains("10"))   n = 10;
   if (opt.Contains("100"))  n = 100;
   if (opt.Contains("1000")) n = 1000;

   printf("\n**********************************************\n");
   printf("*    Index of Tree: %s/%s\n",fTree->GetName(),fTree->GetTitle());
   printf("**********************************************\n");
   printf("%8s : %16s : %16s\n","serial",fMajorName.Data(),fMinorName.Data());
   printf("**********************************************\n");
   for (Long64_t i=0;i<n;i++) {
      Long64_t minor = fIndexValues[i] & 0xffff;
      Long64_t major = fIndexValues[i]>>31;
      printf("%8lld :         %8lld :         %8lld\n",i,major,minor);
   }
}

//______________________________________________________________________________
 void TTreeIndex::Streamer(TBuffer &R__b)
{
   // Stream an object of class TTreeIndex.
   // Note that this Streamer should be changed to an automatic Streamer
   // once TStreamerInfo supports an index of type Long64_t

   UInt_t R__s, R__c;
   if (R__b.IsReading()) {
      Version_t R__v = R__b.ReadVersion(&R__s, &R__c); if (R__v) { }
      TVirtualIndex::Streamer(R__b);
      fMajorName.Streamer(R__b);
      fMinorName.Streamer(R__b);
      R__b >> fN;
      fIndexValues = new Long64_t[fN];
      R__b.ReadFastArray(fIndexValues,fN);
      fIndex      = new Long64_t[fN];
      R__b.ReadFastArray(fIndex,fN);
      R__b.CheckByteCount(R__s, R__c, TTreeIndex::IsA());
   } else {
      R__c = R__b.WriteVersion(TTreeIndex::IsA(), kTRUE);
      TVirtualIndex::Streamer(R__b);
      fMajorName.Streamer(R__b);
      fMinorName.Streamer(R__b);
      R__b << fN;
      R__b.WriteFastArray(fIndexValues, fN);
      R__b.WriteFastArray(fIndex, fN);
      R__b.SetByteCount(R__c, kTRUE);
   }
}

//______________________________________________________________________________
 void TTreeIndex::SetTree(const TTree *T)
{
   // this function is called by TChain::LoadTree and TTreePlayer::UpdateFormulaLeaves
   // when a new Tree is loaded.
   // Because Trees in a TChain may have a different list of leaves, one
   // must update the leaves numbers in the TTreeFormula used by the TreeIndex.

   fTree = (TTree*)T;
   if (fMajorFormula)       {fMajorFormula->SetTree(fTree);        fMajorFormula->UpdateFormulaLeaves();}
   if (fMinorFormula)       {fMinorFormula->SetTree(fTree);        fMinorFormula->UpdateFormulaLeaves();}
   if (fMajorFormulaParent) {fMajorFormulaParent->SetTree(fTree);  fMajorFormulaParent->UpdateFormulaLeaves();}
   if (fMinorFormulaParent) {fMinorFormulaParent->SetTree(fTree);  fMinorFormulaParent->UpdateFormulaLeaves();}
}