| // 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 { |
| |
| // 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) { |
| typedef std::unordered_map<Key, Value, Hash> Map; |
| 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 |
