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/**
* Copyright (c) 2011 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "pch.h"
#include "accumulator.h"
#include "db/pipeline/value.h"
namespace mongo {
intrusive_ptr<const Value> AccumulatorMinMax::evaluate(
const intrusive_ptr<Document> &pDocument) const {
verify(vpOperand.size() == 1);
intrusive_ptr<const Value> prhs(vpOperand[0]->evaluate(pDocument));
/* if this is the first value, just use it */
if (!pValue.get())
pValue = prhs;
else {
/* compare with the current value; swap if appropriate */
int cmp = Value::compare(pValue, prhs) * sense;
if (cmp > 0)
pValue = prhs;
}
return pValue;
}
AccumulatorMinMax::AccumulatorMinMax(int theSense):
AccumulatorSingleValue(),
sense(theSense) {
verify((sense == 1) || (sense == -1));
}
intrusive_ptr<Accumulator> AccumulatorMinMax::createMin(
const intrusive_ptr<ExpressionContext> &pCtx) {
intrusive_ptr<AccumulatorMinMax> pAccumulator(
new AccumulatorMinMax(1));
return pAccumulator;
}
intrusive_ptr<Accumulator> AccumulatorMinMax::createMax(
const intrusive_ptr<ExpressionContext> &pCtx) {
intrusive_ptr<AccumulatorMinMax> pAccumulator(
new AccumulatorMinMax(-1));
return pAccumulator;
}
const char *AccumulatorMinMax::getOpName() const {
if (sense == 1)
return "$min";
return "$max";
}
}
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