RColumn.cxx

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/// \file RColumn.cxx
/// \ingroup NTuple
/// \author Jakob Blomer <jblomer@cern.ch>
/// \date 2018-10-04
 
/*************************************************************************
 * Copyright (C) 1995-2019, 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 <ROOT/RColumn.hxx>
#include <ROOT/RNTupleDescriptor.hxx>
#include <ROOT/RPageStorage.hxx>
 
#include <TError.h>
 
#include <algorithm>
#include <cassert>
#include <utility>
 
using ROOT::Internal::RPageSink;
using ROOT::Internal::RPageSource;
 
ROOT::Internal::RColumn::RColumn(ENTupleColumnType type, std::uint32_t columnIndex, std::uint16_t representationIndex)
   : fType(type), fIndex(columnIndex), fRepresentationIndex(representationIndex), fTeam({this})
{
}
 
ROOT::Internal::RColumn::~RColumn()
{
   if (fHandleSink)
      fPageSink->DropColumn(fHandleSink);
   if (fHandleSource)
      fPageSource->DropColumn(fHandleSource);
}
 
void ROOT::Internal::RColumn::ConnectPageSink(ROOT::DescriptorId_t fieldId, RPageSink &pageSink,
                                              ROOT::NTupleSize_t firstElementIndex)
{
   fInitialNElements = pageSink.GetWriteOptions().GetInitialUnzippedPageSize() / fElement->GetSize();
   if (fInitialNElements < 1) {
      throw RException(R__FAIL("initial page size is too small for at least one element"));
   }
 
   fPageSink = &pageSink;
   fFirstElementIndex = firstElementIndex;
   fHandleSink = fPageSink->AddColumn(fieldId, *this);
   fOnDiskId = fPageSink->GetColumnId(fHandleSink);
   fWritePage = fPageSink->ReservePage(fHandleSink, fInitialNElements);
   if (fWritePage.IsNull())
      throw RException(R__FAIL("page buffer memory budget too small"));
}
 
void ROOT::Internal::RColumn::ConnectPageSource(ROOT::DescriptorId_t fieldId, RPageSource &pageSource)
{
   fPageSource = &pageSource;
   fHandleSource = fPageSource->AddColumn(fieldId, *this);
   fNElements = fPageSource->GetNElements(fHandleSource);
   fOnDiskId = fPageSource->GetColumnId(fHandleSource);
   {
      auto descriptorGuard = fPageSource->GetSharedDescriptorGuard();
      fFirstElementIndex = descriptorGuard->GetColumnDescriptor(fOnDiskId).GetFirstElementIndex();
   }
}
 
void ROOT::Internal::RColumn::Flush()
{
   if (fWritePage.GetNElements() == 0)
      return;
 
   fPageSink->CommitPage(fHandleSink, fWritePage);
   fWritePage = fPageSink->ReservePage(fHandleSink, fInitialNElements);
   R__ASSERT(!fWritePage.IsNull());
   fWritePage.Reset(fNElements);
}
 
void ROOT::Internal::RColumn::CommitSuppressed()
{
   fPageSink->CommitSuppressedColumn(fHandleSink);
}
 
bool ROOT::Internal::RColumn::TryMapPage(ROOT::NTupleSize_t globalIndex)
{
   const auto nTeam = fTeam.size();
   std::size_t iTeam = 1;
   do {
      fReadPageRef = fPageSource->LoadPage(fTeam.at(fLastGoodTeamIdx)->GetHandleSource(), globalIndex);
      if (!fReadPageRef.Get().IsNull())
         break;
      fLastGoodTeamIdx = (fLastGoodTeamIdx + 1) % nTeam;
      iTeam++;
   } while (iTeam <= nTeam);
 
   return fReadPageRef.Get().Contains(globalIndex);
}
 
bool ROOT::Internal::RColumn::TryMapPage(RNTupleLocalIndex localIndex)
{
   const auto nTeam = fTeam.size();
   std::size_t iTeam = 1;
   do {
      fReadPageRef = fPageSource->LoadPage(fTeam.at(fLastGoodTeamIdx)->GetHandleSource(), localIndex);
      if (!fReadPageRef.Get().IsNull())
         break;
      fLastGoodTeamIdx = (fLastGoodTeamIdx + 1) % nTeam;
      iTeam++;
   } while (iTeam <= nTeam);
 
   return fReadPageRef.Get().Contains(localIndex);
}
 
void ROOT::Internal::RColumn::MergeTeams(RColumn &other)
{
   // We are working on very small vectors here, so quadratic complexity works
   for (auto *c : other.fTeam) {
      if (std::find(fTeam.begin(), fTeam.end(), c) == fTeam.end())
         fTeam.emplace_back(c);
   }
 
   for (auto c : fTeam) {
      if (c == this)
         continue;
      c->fTeam = fTeam;
   }
}