types: add first, returns first true argument

This commit is contained in:
Danny Robson 2014-07-07 15:18:27 +10:00
parent c9e46f986e
commit 5c862400a4

View File

@ -14,18 +14,18 @@
* You should have received a copy of the GNU General Public License * You should have received a copy of the GNU General Public License
* along with libgim. If not, see <http://www.gnu.org/licenses/>. * along with libgim. If not, see <http://www.gnu.org/licenses/>.
* *
* Copyright 2011 Danny Robson <danny@nerdcruft.net> * Copyright 2011-2014 Danny Robson <danny@nerdcruft.net>
*/ */
#ifndef __UTIL_TYPES_HPP #ifndef __UTIL_TYPES_HPP
#define __UTIL_TYPES_HPP #define __UTIL_TYPES_HPP
#include "platform.hpp"
#include <cstdint> #include <cstdint>
#include <cstdlib> #include <cstdlib>
#include <memory> #include <memory>
#include <stdexcept>
//-----------------------------------------------------------------------------
/// Returns the number of elements of a statically allocated array /// Returns the number of elements of a statically allocated array
template <typename T, size_t N> template <typename T, size_t N>
constexpr size_t elems(const T (&)[N]) constexpr size_t elems(const T (&)[N])
@ -38,4 +38,24 @@ make_unique(Args&&... args) {
return std::unique_ptr<T> (new T(std::forward<Args>(args)...)); return std::unique_ptr<T> (new T(std::forward<Args>(args)...));
} }
//-----------------------------------------------------------------------------
template <class T>
T
first (T a) {
if (a)
return a;
throw std::logic_error ("no valid object");
}
template <class T, class ...Args>
T
first (T a, Args&& ...b) {
if (a)
return a;
return first (std::forward<Args>(b)...);
}
#endif #endif