38 lines
1.0 KiB
C++
38 lines
1.0 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <cassert>
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#include <limits>
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#include <type_traits>
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#include <folly/Likely.h>
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namespace folly {
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template <typename T, typename = std::enable_if_t<std::is_unsigned<T>::value>>
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bool checked_add(T* result, T a, T b) {
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assert(result != nullptr);
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if (FOLLY_LIKELY(a < std::numeric_limits<T>::max() - b)) {
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*result = a + b;
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return true;
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} else {
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*result = {};
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return false;
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}
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}
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} // namespace folly
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