2020-04-24 12:52:47 -07:00

79 lines
2.3 KiB
C++

/**
This file is a part of rexy's general purpose library
Copyright (C) 2020 rexy712
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef REXY_DETAIL_UTIL_HPP
#define REXY_DETAIL_UTIL_HPP
#include <cstddef> //size_t
namespace rexy::detail{
namespace{
//including <algorithm> causes long compile times. so just make my own max instead
template<class T>
constexpr const T& max(const T& a, const T& b){
return (a < b) ? b : a;
}
template<class T>
constexpr const T& min(const T& a, const T& b){
return (a > b) ? b : a;
}
constexpr size_t cx_strlen(const char* c){
size_t i = 0;
for(;c[i];++i);
return i;
}
constexpr int cx_strcmp(const char* l, const char* r){
using uchar = unsigned char;
for(;*l == *r && *l;++l, ++r);
return (uchar{*l}) - (uchar{*r});
}
} //anonymous namespace
} //namespace detail
//std::swap and std::exchange aren't constexpr until c++20
#if __cplusplus > 201703L
#include <utility>
#define rexy_cx_swap(...) std::swap(__VA_ARGS__)
#define rexy_cx_exchange(...) std::exchange(__VA_ARGS__)
#else
#include <type_traits>
namespace rexy::detail{
namespace{
template<class T>
constexpr void cx_swap(T& a, T& b)noexcept(std::is_nothrow_move_constructible<T>::value &&
std::is_nothrow_move_assignable<T>::value)
{
T tmp = std::move(a);
a = std::move(b);
b = std::move(tmp);
}
template<class T, class U = T>
constexpr T cx_exchange(T& t, U&& u){
T old = std::move(t);
t = std::forward<U>(u);
return old;
}
}
} //namespace detail
#define rexy_cx_swap(...) detail::cx_swap(__VA_ARGS__)
#define rexy_cx_exchange(...) detail::cx_exchange(__VA_ARGS__)
#endif
#endif