TEntryListBlock.cxx

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// @(#)root/tree:$Id$
// Author: Anna Kreshuk 27/10/2006

/*************************************************************************
 * Copyright (C) 1995-2006, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

/** \class TEntryListBlock
\ingroup tree

Used by TEntryList to store the entry numbers.

There are 2 ways to represent entry numbers in a TEntryListBlock:

 1. as bits, where passing entry numbers are assigned 1, not passing - 0
 2. as a simple array of entry numbers
  - storing the numbers of entries that pass
  - storing the numbers of entries that don't pass

In both cases, a UShort_t* is used. The second option is better in case
less than 1/16 or more than 15/16 of entries pass the selection, and the representation can be
changed by calling OptimizeStorage() function.
When the block is being filled, it's always stored as bits, and the OptimizeStorage()
function is called by TEntryList when it starts filling the next block. If
Enter() or Remove() is called after OptimizeStorage(), representation is
again changed to 1).

Begin_Macro(source)
entrylistblock_figure1.C
End_Macro

## Operations on blocks (see also function comments)

 - __Merge__() - adds all entries from one block to the other. If the first block
             uses array representation, it's changed to bits representation only
             if the total number of passing entries is still less than kBlockSize
 - __GetEntry(n)__ - returns n-th non-zero entry.
 - __Next__()      - return next non-zero entry. In case of representation 1), Next()
                 is faster than GetEntry()
*/

#include "TEntryListBlock.h"
#include "TString.h"

ClassImp(TEntryListBlock)

////////////////////////////////////////////////////////////////////////////////
/// Default c-tor

TEntryListBlock::TEntryListBlock()
{
   fIndices = 0;
   fN = kBlockSize;
   fNPassed = 0;
   fType = -1;
   fPassing = 1;
   fCurrent = 0;
   fLastIndexReturned = -1;
   fLastIndexQueried = -1;
}

////////////////////////////////////////////////////////////////////////////////
/// Copy c-tor

TEntryListBlock::TEntryListBlock(const TEntryListBlock &eblock) : TObject(eblock)
{
   fN = eblock.fN;
   if (eblock.fIndices){
      fIndices = new UShort_t[fN];
      for (Int_t i=0; i<fN; i++)
         fIndices[i] = eblock.fIndices[i];
   } else {
      fIndices = 0;
   }
   fNPassed = eblock.fNPassed;
   fType = eblock.fType;
   fPassing = eblock.fPassing;
   fCurrent = eblock.fCurrent;
   fLastIndexReturned = -1;
   fLastIndexQueried = -1;
}

////////////////////////////////////////////////////////////////////////////////
/// Destructor

TEntryListBlock::~TEntryListBlock()
{
   if (fIndices)
      delete [] fIndices;
   fIndices = 0;
}

////////////////////////////////////////////////////////////////////////////////

TEntryListBlock &TEntryListBlock::operator=(const TEntryListBlock &eblock)
{
   if (this != &eblock) {
      if (fIndices)
         delete [] fIndices;

      fN = eblock.fN;
      if (eblock.fIndices){
         fIndices = new UShort_t[fN];
         for (Int_t i=0; i<fN; i++)
            fIndices[i] = eblock.fIndices[i];
      } else {
         fIndices = 0;
      }
      fNPassed = eblock.fNPassed;
      fType = eblock.fType;
      fPassing = eblock.fPassing;
      fCurrent = eblock.fCurrent;
      fLastIndexReturned = -1;
      fLastIndexQueried = -1;
   }
   return *this;
}

////////////////////////////////////////////////////////////////////////////////
/// If the block has already been optimized and the entries
/// are stored as a list and not as bits, trying to enter a new entry
/// will make the block switch to bits representation

Bool_t TEntryListBlock::Enter(Int_t entry)
{
   if (entry > kBlockSize*16) {
      Error("Enter", "illegal entry value!");
      return 0;
   }
   if (!fIndices){
      fIndices = new UShort_t[kBlockSize] ;
      for (Int_t i=0; i<kBlockSize; i++)
         fIndices[i] = 0;
      fType = 0; //start in bits
   }
   if (fType==0){
      //bits
      Int_t i = entry>>4;
      Int_t j = entry & 15;
      if ((fIndices[i] & (1<<j))==0){
         fIndices[i] |= 1<<j;
         fNPassed++;
         return 1;
      } else {
         return 0;
      }
   }
   //list
   //change to bits
   UShort_t *bits = new UShort_t[kBlockSize];
   Transform(1, bits);
   Enter(entry);
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Remove entry #entry
/// If the block has already been optimized and the entries
/// are stored as a list and not as bits, trying to remove a new entry
/// will make the block switch to bits representation

Bool_t TEntryListBlock::Remove(Int_t entry)
{
   if (entry > kBlockSize*16) {
      Error("Remove", "Illegal entry value!\n");
      return 0;
   }
   if (fType==0){
      Int_t i = entry>>4;
      Int_t j = entry & 15;
      if ((fIndices[i] & (1<<j))!=0){
         fIndices[i] &= (0xFFFF^(1<<j));
         fNPassed--;
         return 1;
      } else {
         return 0;
      }
   }
   //list
   //change to bits
   UShort_t *bits = new UShort_t[kBlockSize];
   Transform(1, bits);
   return Remove(entry);
   //return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// True if the block contains entry #entry

Int_t TEntryListBlock::Contains(Int_t entry)
{
   if (entry > kBlockSize*16) {
      Error("Contains", "Illegal entry value!\n");
      return 0;
   }
   if (!fIndices && fPassing)
      return 0;
   if (fType==0 && fIndices){
      //bits
      Int_t i = entry>>4;
      Int_t j = entry & 15;
      Bool_t result = (fIndices[i] & (1<<j))!=0;
      return result;
   }
   //list
   if (entry < fCurrent) fCurrent = 0;
   if (fPassing && fIndices){
      for (Int_t i = fCurrent; i<fNPassed; i++){
         if (fIndices[i]==entry){
            fCurrent = i;
            return kTRUE;
         }
      }
   } else {
      if (!fIndices || fNPassed==0){
         //all entries pass
         return kTRUE;
      }
      if (entry > fIndices[fNPassed-1])
         return kTRUE;
      for (Int_t i= fCurrent; i<fNPassed; i++){
         if (fIndices[i]==entry){
            fCurrent = i;
            return kFALSE;
         }
         if (fIndices[i]>entry){
            fCurrent = i;
            return kTRUE;
         }
      }
   }
   return 0;
}

////////////////////////////////////////////////////////////////////////////////
/// Merge with the other block
/// Returns the resulting number of entries in the block

Int_t TEntryListBlock::Merge(TEntryListBlock *block)
{
   Int_t i, j;
   if (block->GetNPassed() == 0) return GetNPassed();
   if (GetNPassed() == 0){
      //this block is empty
      fN = block->fN;
      fIndices = new UShort_t[fN];
      for (i=0; i<fN; i++)
         fIndices[i] = block->fIndices[i];
      fNPassed = block->fNPassed;
      fType = block->fType;
      fPassing = block->fPassing;
      fCurrent = block->fCurrent;
      fLastIndexReturned = -1;
      fLastIndexQueried = -1;
      return fNPassed;
   }
   if (fType==0){
      //stored as bits
      if (block->fType == 0){
         for (i=0; i<kBlockSize*16; i++){
            if (block->Contains(i))
               Enter(i);
         }
      } else {
         if (block->fPassing){
            //the other block stores entries that pass
            for (i=0; i<block->fNPassed; i++){
               Enter(block->fIndices[i]);
            }
         } else {
            //the other block stores entries that don't pass
            if (block->fNPassed==0){
               for (i=0; i<kBlockSize*16; i++){
                  Enter(i);
               }
            }
            for (j=0; j<block->fIndices[0]; j++)
               Enter(j);
            for (i=0; i<block->fNPassed-1; i++){
               for (j=block->fIndices[i]+1; j<block->fIndices[i+1]; j++){
                  Enter(j);
               }
            }
            for (j=block->fIndices[block->fNPassed-1]+1; j<kBlockSize*16; j++)
               Enter(j);
         }
      }
   } else {
      //stored as a list
      if (GetNPassed() + block->GetNPassed() > kBlockSize){
         //change to bits
         UShort_t *bits = new UShort_t[kBlockSize];
         Transform(1, bits);
         Merge(block);
      } else {
         //this is only possible if fPassing=1 in both blocks
         if (block->fType==1){
            //second block stored as a list
            //make a bigger list
            Int_t en = block->fNPassed;
            Int_t newsize = fNPassed + en;
            UShort_t *newlist = new UShort_t[newsize];
            UShort_t *elst = block->fIndices;
            Int_t newpos, elpos;
            newpos = elpos = 0;
            for (i=0; i<fNPassed; i++) {
               while (elpos < en && fIndices[i] > elst[elpos]) {
                  newlist[newpos] = elst[elpos];
                  newpos++;
                  elpos++;
               }
               if (fIndices[i] == elst[elpos]) elpos++;
               newlist[newpos] = fIndices[i];
               newpos++;
            }
            while (elpos < en) {
               newlist[newpos] = elst[elpos];
               newpos++;
               elpos++;
            }
            delete [] fIndices;
            fIndices = newlist;
            fNPassed = newpos;
            fN = fNPassed;
         } else {
            //second block is stored as bits

            Int_t en = block->fNPassed;
            Int_t newsize = fNPassed + en;
            UShort_t *newlist = new UShort_t[newsize];
            Int_t newpos, current;
            newpos = current = 0;
            for (i=0; i<kBlockSize*16; i++){
               if (!block->Contains(i)) continue;
               while(current < fNPassed && fIndices[current]<i){
                  newlist[newpos] = fIndices[current];
                  current++;
                  newpos++;
               }
               if (fIndices[current]==i) current++;
               newlist[newpos] = i;
               newpos++;
            }
            while(current<fNPassed){
               newlist[newpos] = fIndices[current];
               newpos++;
               current++;
            }
            delete [] fIndices;
            fIndices = newlist;
            fNPassed = newpos;
            fN = fNPassed;
         }
      }
   }
   fLastIndexQueried = -1;
   fLastIndexReturned = -1;
   OptimizeStorage();
   return GetNPassed();
}

////////////////////////////////////////////////////////////////////////////////
/// Returns the number of entries, passing the selection.
/// In case, when the block stores entries that pass (fPassing=1) returns fNPassed

Int_t TEntryListBlock::GetNPassed()
{
   if (fPassing)
      return fNPassed;
   else
      return kBlockSize*16-fNPassed;
}

////////////////////////////////////////////////////////////////////////////////
/// Return entry #entry.
/// See also Next()

Int_t TEntryListBlock::GetEntry(Int_t entry)
{
   if (entry > kBlockSize*16) return -1;
   if (entry > GetNPassed()) return -1;
   if (entry == fLastIndexQueried+1) return Next();
   else {
      Int_t i=0; Int_t j=0; Int_t entries_found=0;
      if (fType==0){
         if ((fIndices[i] & (1<<j))!=0)
            entries_found++;
         while (entries_found<entry+1){
            if (j==15){i++; j=0;}
            else j++;
            if ((fIndices[i] & (1<<j))!=0)
               entries_found++;
         }
         fLastIndexQueried = entry;
         fLastIndexReturned = i*16+j;
         return fLastIndexReturned;
      }
      if (fType==1){
         if (fPassing){
            fLastIndexQueried = entry;
            fLastIndexReturned = fIndices[entry];
            return fIndices[entry];
         } else {
            fLastIndexQueried = entry;
            if (!fIndices || fNPassed==0){
               //all entries pass
               fLastIndexReturned = entry;
               return fLastIndexReturned;
            }
            for (i=0; i<fIndices[0]; i++){
               entries_found++;
               if (entries_found==entry+1){
                  fLastIndexReturned = i;
                  return fLastIndexReturned;
               }
            }
            for (i=0; i<fNPassed-1; i++){
               for (j=fIndices[i]+1; j<fIndices[i+1]; j++){
                  entries_found++;
                  if (entries_found==entry+1){
                     fLastIndexReturned = j;
                     return fLastIndexReturned;
                  }
               }
            }
            for (j=fIndices[fNPassed-1]+1; j<kBlockSize*16; j++){
               entries_found++;
               if (entries_found==entry+1){
                  fLastIndexReturned = j;
                  return fLastIndexReturned;
               }
            }
         }
      }
      return -1;
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Return the next non-zero entry
/// Faster than GetEntry() function

Int_t TEntryListBlock::Next()
{
   if (fLastIndexQueried==GetNPassed()-1){
      fLastIndexQueried=-1;
      fLastIndexReturned = -1;
      return -1;
   }

   if (fType==0) {
      //bits
      Int_t i=0;
      Int_t j=0;
      fLastIndexReturned++;
      i = fLastIndexReturned>>4;
      j = fLastIndexReturned & 15;
      Bool_t result=(fIndices[i] & (1<<j))!=0;
      while (result==0){
         if (j==15) {j=0; i++;}
         else j++;
         result = (fIndices[i] & (1<<j))!=0;
      }
      fLastIndexReturned = i*16+j;
      fLastIndexQueried++;
      return fLastIndexReturned;

   }
   if (fType==1) {
      fLastIndexQueried++;
      if (fPassing){
         fLastIndexReturned = fIndices[fLastIndexQueried];
         return fIndices[fLastIndexQueried];
      } else {
         fLastIndexReturned++;
         while (!Contains(fLastIndexReturned)){
            fLastIndexReturned++;
            }
         return fLastIndexReturned;
      }

   }
   return -1;
}

////////////////////////////////////////////////////////////////////////////////
/// Print the entries in this block

void TEntryListBlock::Print(const Option_t *option) const
{
   TString opt = option;
   opt.ToUpper();
   if (opt.Contains("A")) PrintWithShift(0);
}

////////////////////////////////////////////////////////////////////////////////
/// Print the indices of this block + shift (used from TEntryList::Print()) to
/// print the corrent values

void TEntryListBlock::PrintWithShift(Int_t shift) const
{
   Int_t i;
   if (fType==0){
      Int_t ibit, ibite;
      Bool_t result;
      for (i=0; i<kBlockSize*16; i++){
         ibite = i>>4;
         ibit = i & 15;
         result = (fIndices[ibite] & (1<<ibit))!=0;
         if (result)
            printf("%d\n", i+shift);
      }
   } else {
      if (fPassing){
         for (i=0; i<fNPassed; i++){
            printf("%d\n", fIndices[i]+shift);
         }
      } else {
         if (fNPassed==0){
            for (i=0; i<kBlockSize*16; i++)
               printf("%d\n", i+shift);
            return;
         }
         for (i=0; i<fIndices[0]; i++){
            printf("%d\n", i+shift);
         }
         for (i=0; i<fNPassed-1; i++){
            for (Int_t j=fIndices[i]+1; j<fIndices[i+1]; j++){
               printf("%d\n", j+shift);
            }
         }
         for (Int_t j=fIndices[fNPassed-1]+1; j<kBlockSize*16; j++){
            printf("%d\n", j+shift);
         }
      }
   }
}

////////////////////////////////////////////////////////////////////////////////
/// If there are < kBlockSize or >kBlockSize*15 entries, change to an array
/// representation

void TEntryListBlock::OptimizeStorage()
{
   if (fType!=0) return;
   if (fNPassed > kBlockSize*15)
      fPassing = 0;
   if (fNPassed<kBlockSize || !fPassing){
      //less than 4000 entries passing, makes sense to change from bits to list
      UShort_t *indexnew = new UShort_t[fNPassed];
      Transform(0, indexnew);
   }
}

////////////////////////////////////////////////////////////////////////////////
/// Transform the existing fIndices
/// - dir=0 - transform from bits to a list
/// - dir=1 - tranform from a list to bits

void TEntryListBlock::Transform(Bool_t dir, UShort_t *indexnew)
{
   Int_t i=0;
   Int_t ilist = 0;
   Int_t ibite, ibit;
   if (!dir) {
         for (i=0; i<kBlockSize*16; i++){
            ibite = i >> 4;
            ibit = i & 15;
            Bool_t result = (fIndices[ibite] & (1<<ibit))!=0;
            if (result && fPassing){
               //fill with the entries that pass
               indexnew[ilist] = i;
               ilist++;
            }
            else if (!result && !fPassing){
               //fill with the entries that don't pass
               indexnew[ilist] = i;
               ilist++;
            }
         }
      if (fIndices)
         delete [] fIndices;
      fIndices = indexnew;
      fType = 1;
      if (!fPassing)
         fNPassed = kBlockSize*16-fNPassed;
      fN = fNPassed;
      return;
   }

   if (fPassing){
      for (i=0; i<kBlockSize; i++)
         indexnew[i] = 0;
      for (i=0; i<fNPassed; i++){
         ibite = fIndices[i]>>4;
         ibit = fIndices[i] & 15;
         indexnew[ibite] |= 1<<ibit;
      }
   } else {
      for (i=0; i<kBlockSize; i++)
         indexnew[i] = 65535;
      for (i=0; i<fNPassed; i++){
         ibite = fIndices[i]>>4;
         ibit = fIndices[i] & 15;
         indexnew[ibite] ^= 1<<ibit;
      }
      fNPassed = kBlockSize*16-fNPassed;
   }
   if (fIndices)
      delete [] fIndices;
   fIndices = indexnew;
   fType = 0;
   fN = kBlockSize;
   fPassing = 1;
   return;
}