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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kIndex
#include "mongo/platform/basic.h"
#include "mongo/db/storage/mmap_v1/catalog/hashtab.h"
#include "mongo/util/log.h"
namespace mongo {
int NamespaceHashTable::_find(const Namespace& k, bool& found) const {
found = false;
int h = k.hash();
int i = h % n;
int start = i;
int chain = 0;
int firstNonUsed = -1;
while (1) {
if (!_nodes(i).inUse()) {
if (firstNonUsed < 0)
firstNonUsed = i;
}
if (_nodes(i).hash == h && _nodes(i).key == k) {
if (chain >= 200)
log() << "warning: hashtable " << _name << " long chain " << std::endl;
found = true;
return i;
}
chain++;
i = (i + 1) % n;
if (i == start) {
// shouldn't get here / defensive for infinite loops
log() << "error: hashtable " << _name << " is full n:" << n << std::endl;
return -1;
}
if (chain >= maxChain) {
if (firstNonUsed >= 0)
return firstNonUsed;
log() << "error: hashtable " << _name << " max chain reached:" << maxChain << std::endl;
return -1;
}
}
}
/* buf must be all zeroes on initialization. */
NamespaceHashTable::NamespaceHashTable(void* buf, int buflen, const char* name)
: _name(name), _buf(buf) {
n = buflen / sizeof(Node);
if ((n & 1) == 0) {
n--;
}
maxChain = (int)(n * 0.05);
}
} // namespace mongo
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