Files
secondo/Algebras/CRel/Operators/ToTuples.cpp
2026-01-23 17:03:45 +08:00

140 lines
3.2 KiB
C++

/*
----
This file is part of SECONDO.
Copyright (C) 2004, University in Hagen, Department of Computer Science,
Database Systems for New Applications.
SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
SECONDO is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
----
*/
#include "ToTuples.h"
#include <cstdint>
#include "ListUtils.h"
#include "LogMsg.h"
#include "OperatorUtils.h"
#include "QueryProcessor.h"
#include "SecondoSystem.h"
#include "StreamValueMapping.h"
#include <string>
#include "Symbols.h"
#include "../TBlock.h"
#include "../TypeConstructors/TBlockTC.h"
#include "TypeUtils.h"
using namespace CRelAlgebra;
using namespace CRelAlgebra::Operators;
using listutils::isStream;
using std::string;
extern NestedList *nl;
extern QueryProcessor *qp;
ToTuples::ToTuples() :
Operator(info, StreamValueMapping<State>, TypeMapping)
{
}
const OperatorInfo ToTuples::info = OperatorInfo(
"totuples", "stream(tblock) -> stream(tuple)",
"_ totuples",
"Transforms a stream of tuple blocks into one of tuples.",
"");
ListExpr ToTuples::TypeMapping(ListExpr args)
{
//Expect one parameter
if (!nl->HasLength(args, 1))
{
return GetTypeError("Expected one argument.");
}
//Check first parameter for stream
ListExpr stream = nl->First(args);
if (!isStream(stream))
{
return GetTypeError(0, "Isn't a stream.");
}
const ListExpr tblockType = GetStreamType(stream);
//Check first parameter's stream type for 'tblock'
if (!TBlockTI::Check(tblockType))
{
return GetTypeError(0, "Isn't a stream of tblock.");
}
//Result is a stream of 'tuple'
return TBlockTI(tblockType, false).GetTupleTypeExpr(true);
}
ToTuples::State::State(ArgVector args, Supplier s) :
m_stream(args[0]),
m_block(nullptr),
m_tupleType(new TupleType(
SecondoSystem::GetCatalog()->NumericType(nl->Second(qp->GetType(s)))))
{
m_stream.open();
}
ToTuples::State::~State()
{
m_tupleType->DeleteIfAllowed();
if (m_block != nullptr)
{
m_block->DecRef();
}
}
Tuple *ToTuples::State::Request()
{
if (!m_blockIterator.IsValid() || !m_blockIterator.MoveToNext())
{
do
{
if (m_block != nullptr)
{
m_block->DecRef();
}
if ((m_block = m_stream.request()) == nullptr)
{
return nullptr;
}
}
while (!(m_blockIterator = m_block->GetFilteredIterator()).IsValid());
}
const TBlockEntry &blockTuple = m_blockIterator.Get();
Tuple *tuple = new Tuple(m_tupleType);
const uint64_t columnCount = m_block->GetColumnCount();
for (uint64_t i = 0; i < columnCount; ++i)
{
Attribute *attribute = blockTuple[i].GetAttribute(true);
tuple->PutAttribute(i, attribute);
}
return tuple;
}