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Diffstat (limited to 'src/mongo/util/container_size_helper.h')
-rw-r--r-- | src/mongo/util/container_size_helper.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/mongo/util/container_size_helper.h b/src/mongo/util/container_size_helper.h new file mode 100644 index 00000000000..406e3607d1c --- /dev/null +++ b/src/mongo/util/container_size_helper.h @@ -0,0 +1,73 @@ +/** + * Copyright (C) 2019-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. + */ + +#pragma once + +#include <vector> + +namespace mongo { +namespace container_size_helper { +/** + * Returns the estimate of the number of bytes consumed by the vector, based on the current capacity + * of the vector and the size of objects of type T. Does not incorporate the size of any owned + * objects that are pointed to by T. Also, does not incorporate sizeof(vector). + */ +template <class T> +uint64_t estimateObjectSizeInBytes(const std::vector<T>& vector) { + return static_cast<uint64_t>(vector.capacity()) * sizeof(T); +} + +/** + * Returns the estimate of the number of bytes consumed by the container, based on the current + * capacity of the container and the size of objects of type 'T::value_type'. Does not incorporate + * the size of any owned objects that are pointed to by 'T::value_type'. Also, does not incorporate + * sizeof(container). + */ +template <class T> +uint64_t estimateObjectSizeInBytes(const T& container) { + return static_cast<uint64_t>(container.size()) * sizeof(typename T::value_type); +} + +/** + * Returns the estimate by recursively calculating the memory owned by each element of the + * container. The 'function' should calculate the overall size of each individual element of the + * 'container'. + * When 'includeShallowSize' is true, adds the size of each container element. + */ +template <class T, class Function> +uint64_t estimateObjectSizeInBytes(const T& container, Function function, bool includeShallowSize) { + uint64_t result = 0; + for (const auto& element : container) { + result += function(element); + } + result += includeShallowSize ? estimateObjectSizeInBytes(container) : 0; + return result; +} +} // namespace container_size_helper +} // namespace mongo |