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/**
* Copyright (C) 2013 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.
*/
#pragma once
#include <vector>
#include "mongo/db/diskloc.h"
#include "mongo/db/geo/core.h"
#include "mongo/db/geo/shapes.h"
namespace mongo {
class GeoHaystackSearchHopper {
public:
/**
* Constructed with a point, a max distance from that point, and a max number of
* matched points to store.
* @param n The centroid that we're searching
* @param maxDistance The maximum distance to consider from that point
* @param limit The maximum number of results to return
* @param geoField Which field in the provided DiskLoc has the point to test.
*/
GeoHaystackSearchHopper(const BSONObj& nearObj, double maxDistance, unsigned limit,
const string& geoField)
: _near(nearObj), _maxDistance(maxDistance), _limit(limit), _geoField(geoField) { }
// Consider the point in loc, and keep it if it's within _maxDistance (and we have space for
// it)
void consider(const DiskLoc& loc) {
if (limitReached()) return;
Point p(loc.obj().getFieldDotted(_geoField));
if (distance(_near, p) > _maxDistance)
return;
_locs.push_back(loc);
}
int appendResultsTo(BSONArrayBuilder* b) {
for (unsigned i = 0; i <_locs.size(); i++)
b->append(_locs[i].obj());
return _locs.size();
}
// Have we stored as many points as we can?
bool limitReached() const {
return _locs.size() >= _limit;
}
private:
Point _near;
double _maxDistance;
unsigned _limit;
const string _geoField;
vector<DiskLoc> _locs;
};
} // namespace mongo
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