|
|
|
|
// 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 <unordered_map>
|
|
|
|
|
|
|
|
|
|
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*);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|
