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/**
* Copyright (C) 2015 MongoDB 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/db/index/s2_common.h"
#include <cstdlib>
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/geo/geometry_container.h"
#include "mongo/db/query/collation/collator_interface.h"
#include "third_party/s2/s2cellid.h"
#include "third_party/s2/s2regioncoverer.h"
namespace mongo {
// Points will only be indexed at this level
const int kPointIndexedLevel = S2::kMaxCellLevel;
std::string S2IndexingParams::toString() const {
std::stringstream ss;
ss << "maxKeysPerInsert: " << maxKeysPerInsert << std::endl;
ss << "maxCellsInCovering: " << maxCellsInCovering << std::endl;
ss << "finestIndexedLevel: " << finestIndexedLevel << std::endl;
ss << "coarsestIndexedLevel: " << coarsestIndexedLevel << std::endl;
ss << "indexVersion: " << indexVersion << std::endl;
if (collator) {
ss << "collation: " << collator->getSpec().toBSON() << std::endl;
}
return ss.str();
}
void S2IndexingParams::configureCoverer(const GeometryContainer& geoContainer,
S2RegionCoverer* coverer) const {
// Points indexed to the finest level was introduced in version 3
// For backwards compatibility, only do this if the version is > 2
if (indexVersion >= S2_INDEX_VERSION_3 && geoContainer.isPoint()) {
coverer->set_min_level(kPointIndexedLevel);
coverer->set_max_level(kPointIndexedLevel);
} else {
coverer->set_min_level(coarsestIndexedLevel);
coverer->set_max_level(finestIndexedLevel);
}
// This is advisory; the two above are strict.
coverer->set_max_cells(maxCellsInCovering);
}
BSONObj S2CellIdToIndexKey(const S2CellId& cellId, S2IndexVersion indexVersion) {
// The range of an unsigned long long is
// |-----------------|------------------|
// 0 2^32 2^64 - 1
// 000... 100... 111...
// The range of a signed long long is
// |-----------------|------------------|
// -2^63 0 2^63 - 1
// 100... 000... 011...
// S2 gives us an unsigned long long, and we need
// to use signed long longs for the index.
//
// The relative ordering may be changed with unsigned
// numbers around 2^32 being converted to signed
//
// However, because a single cell cannot span over
// more than once face, individual intervals will
// never cross that threshold. Thus, scans will still
// produce the same results.
if (indexVersion >= S2_INDEX_VERSION_3) {
// The size of an index BSONObj in S2 index version 3 is 15 bytes.
// total size (4 bytes) | type code 0x12 (1) | field name "" 0x00 (1) |
// long long cell id (8) | EOO (1)
BSONObjBuilder b(15);
b.append("", static_cast<long long>(cellId.id()));
return b.obj();
}
// The size of an index BSONObj in older versions is 10 ~ 40 bytes.
// total size (4 bytes) | type code 0x12 (1) | field name "" 0x00 (1) |
// cell id string (2 ~ 32) 0x00 (1) | EOO (1)
BSONObjBuilder b;
b.append("", cellId.ToString());
// Return a copy so its buffer size fits the object size.
return b.obj().copy();
}
} // namespace mongo
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