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-BEGIN VERIFY SCRIPT- ./contrib/devtools/copyright_header.py update ./ -END VERIFY SCRIPT- Commits of previous years: - 2021:f47dda2c58- 2020:fa0074e2d8- 2019:aaaaad6ac9
50 lines
1.4 KiB
C++
50 lines
1.4 KiB
C++
// Copyright (c) 2021-2022 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_UTIL_OVERFLOW_H
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#define BITCOIN_UTIL_OVERFLOW_H
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#include <limits>
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#include <optional>
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#include <type_traits>
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template <class T>
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[[nodiscard]] bool AdditionOverflow(const T i, const T j) noexcept
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{
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static_assert(std::is_integral<T>::value, "Integral required.");
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if constexpr (std::numeric_limits<T>::is_signed) {
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return (i > 0 && j > std::numeric_limits<T>::max() - i) ||
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(i < 0 && j < std::numeric_limits<T>::min() - i);
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}
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return std::numeric_limits<T>::max() - i < j;
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}
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template <class T>
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[[nodiscard]] std::optional<T> CheckedAdd(const T i, const T j) noexcept
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{
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if (AdditionOverflow(i, j)) {
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return std::nullopt;
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}
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return i + j;
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}
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template <class T>
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[[nodiscard]] T SaturatingAdd(const T i, const T j) noexcept
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{
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if constexpr (std::numeric_limits<T>::is_signed) {
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if (i > 0 && j > std::numeric_limits<T>::max() - i) {
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return std::numeric_limits<T>::max();
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}
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if (i < 0 && j < std::numeric_limits<T>::min() - i) {
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return std::numeric_limits<T>::min();
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}
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} else {
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if (std::numeric_limits<T>::max() - i < j) {
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return std::numeric_limits<T>::max();
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}
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}
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return i + j;
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}
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#endif // BITCOIN_UTIL_OVERFLOW_H
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