/* This file is part of Telegram Desktop, the official desktop application for the Telegram messaging service. For license and copyright information please follow this link: https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL */ #pragma once namespace base { namespace functors { struct abs_helper { template < typename Type, typename = decltype(0 < std::declval()), typename = decltype(-std::declval())> constexpr Type operator()(Type value) const { return (0 < value) ? value : (-value); } }; constexpr auto abs = abs_helper{}; constexpr auto add = [](auto value) { return [value](auto other) { return value + other; }; }; struct negate_helper { template < typename Type, typename = decltype(-std::declval())> constexpr Type operator()(Type value) const { return -value; } }; constexpr auto negate = negate_helper{}; } // namespace functors } // namespace base