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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/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/accumulator.h"
#include "mongo/db/pipeline/accumulation_statement.h"
#include "mongo/db/pipeline/expression.h"
#include "mongo/db/pipeline/value.h"
namespace mongo {
using boost::intrusive_ptr;
REGISTER_ACCUMULATOR(max, AccumulatorMax::create);
REGISTER_ACCUMULATOR(min, AccumulatorMin::create);
REGISTER_EXPRESSION(max, ExpressionFromAccumulator<AccumulatorMax>::parse);
REGISTER_EXPRESSION(min, ExpressionFromAccumulator<AccumulatorMin>::parse);
const char* AccumulatorMinMax::getOpName() const {
if (_sense == 1)
return "$min";
return "$max";
}
void AccumulatorMinMax::processInternal(const Value& input, bool merging) {
// nullish values should have no impact on result
if (!input.nullish()) {
/* compare with the current value; swap if appropriate */
int cmp = getExpressionContext()->getValueComparator().compare(_val, input) * _sense;
if (cmp > 0 || _val.missing()) { // missing is lower than all other values
_val = input;
_memUsageBytes = sizeof(*this) + input.getApproximateSize() - sizeof(Value);
}
}
}
Value AccumulatorMinMax::getValue(bool toBeMerged) {
if (_val.missing()) {
return Value(BSONNULL);
}
return _val;
}
AccumulatorMinMax::AccumulatorMinMax(const boost::intrusive_ptr<ExpressionContext>& expCtx,
Sense sense)
: Accumulator(expCtx), _sense(sense) {
_memUsageBytes = sizeof(*this);
}
void AccumulatorMinMax::reset() {
_val = Value();
_memUsageBytes = sizeof(*this);
}
intrusive_ptr<Accumulator> AccumulatorMin::create(
const boost::intrusive_ptr<ExpressionContext>& expCtx) {
return new AccumulatorMin(expCtx);
}
intrusive_ptr<Accumulator> AccumulatorMax::create(
const boost::intrusive_ptr<ExpressionContext>& expCtx) {
return new AccumulatorMax(expCtx);
}
}
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