tdesktop/Telegram/SourceFiles/base/functors.h

42 lines
921 B
C++

/*
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<Type>()),
typename = decltype(-std::declval<Type>())>
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<Type>())>
constexpr Type operator()(Type value) const {
return -value;
}
};
constexpr auto negate = negate_helper{};
} // namespace functors
} // namespace base