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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <cstddef>
#include <unordered_map>
#ifdef USE_FOLLY
#include <folly/container/F14Map.h>
#endif
#include "rocksdb/rocksdb_namespace.h"
namespace ROCKSDB_NAMESPACE {
// Helper methods to estimate memroy usage by std containers.
template <class Key, class Value, class Hash>
size_t ApproximateMemoryUsage(
const std::unordered_map<Key, Value, Hash>& umap) {
using Map = std::unordered_map<Key, Value, Hash>;
return sizeof(umap) +
// Size of all items plus a next pointer for each item.
(sizeof(typename Map::value_type) + sizeof(void*)) * umap.size() +
// Size of hash buckets.
umap.bucket_count() * sizeof(void*);
}
#ifdef USE_FOLLY
template <class Key, class Value, class Hash>
size_t ApproximateMemoryUsage(const folly::F14FastMap<Key, Value, Hash>& umap) {
return sizeof(umap) + umap.getAllocatedMemorySize();
}
#endif
} // namespace ROCKSDB_NAMESPACE
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