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

115 lines
3.0 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 "FeedProject.h"
#include "../TypeConstructors/CRelTC.h"
#include "ListUtils.h"
#include "LogMsg.h"
#include "OperatorUtils.h"
#include "Project.h"
#include "QueryProcessor.h"
#include "StandardTypes.h"
#include "StreamValueMapping.h"
#include <string>
#include "Symbols.h"
using namespace CRelAlgebra;
using namespace CRelAlgebra::Operators;
using std::string;
extern NestedList *nl;
extern QueryProcessor *qp;
//FeedProject-------------------------------------------------------------------
FeedProject::FeedProject() :
Operator(info, StreamValueMapping<State>, TypeMapping)
{
}
const OperatorInfo FeedProject::info = OperatorInfo(
"feedproject", "crel x symbol x symbol* -> stream tblock",
"_ feedproject[ list ]",
"Produces a stream of tuple blocks from a relation projected on the columns "
"determined by the provided names.",
"query people feedproject[Name, Age] consume");
ListExpr FeedProject::TypeMapping(ListExpr args)
{
if (!nl->HasLength(args, 2))
{
return GetTypeError("Expected two arguments.");
}
const ListExpr crelType = nl->First(args);
if (!CRelTI::Check(crelType))
{
return GetTypeError(0, "relation", "Not a crel.");
}
const Project::Info info(CRelTI(crelType, false), nl->Second(args));
if (info.HasError())
{
return GetTypeError(1, "column names", info.GetError());
}
return nl->ThreeElemList(nl->SymbolAtom(Symbols::APPEND()),
info.GetIndicesExpr(),
info.GetBlockTypeInfo().GetTypeExpr(true));
}
//FeedProject::State------------------------------------------------------------
FeedProject::State::State(ArgVector args, Supplier s) :
m_blockIterator(((CRel*)args[0].addr)->GetBlockIterator())
{
qp->DeleteResultStorage(s);
const uint64_t indexCount = ((CcInt*)args[2].addr)->GetValue();
for (uint64_t i = 0; i < indexCount; ++i)
{
m_indices.push_back(((CcInt*)args[i + 3].addr)->GetValue());
}
}
TBlock *FeedProject::State::Request()
{
if (m_blockIterator.IsValid())
{
TBlock *block = new TBlock(m_blockIterator.Get(), &m_indices.front(),
m_indices.size());
m_blockIterator.MoveToNext();
return block;
}
return nullptr;
}