mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-12-23 21:25:49 +00:00
68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
/*=============================================================================
|
|
Copyright (c) 2011-2013 Bolero MURAKAMI
|
|
https://github.com/bolero-MURAKAMI/Sprout
|
|
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
=============================================================================*/
|
|
#ifndef SPROUT_BIT_CLZ_HPP
|
|
#define SPROUT_BIT_CLZ_HPP
|
|
|
|
#include <climits>
|
|
#include <type_traits>
|
|
#include <sprout/config.hpp>
|
|
|
|
namespace sprout {
|
|
namespace detail {
|
|
# if SPROUT_USE_BUILTIN_BIT_OPERATION
|
|
inline SPROUT_CONSTEXPR int
|
|
clz(unsigned n) {
|
|
return __builtin_clz(n);
|
|
}
|
|
inline SPROUT_CONSTEXPR int
|
|
clz(unsigned long n) {
|
|
return __builtin_clzl(n);
|
|
}
|
|
inline SPROUT_CONSTEXPR int
|
|
clz(unsigned long long n) {
|
|
return __builtin_clzll(n);
|
|
}
|
|
# endif
|
|
template<typename T>
|
|
inline SPROUT_CONSTEXPR int
|
|
clz_impl(T n, T m = T(1) << (CHAR_BIT * sizeof(T) - 1)) {
|
|
return m == 0 || n & m ? 0
|
|
: 1 + sprout::detail::clz_impl(n, static_cast<T>(m >> 1))
|
|
;
|
|
}
|
|
template<typename T>
|
|
inline SPROUT_CONSTEXPR typename std::enable_if<
|
|
std::is_unsigned<T>::value,
|
|
int
|
|
>::type
|
|
clz(T n) {
|
|
return sprout::detail::clz_impl(static_cast<T>(n));
|
|
}
|
|
template<typename T>
|
|
inline SPROUT_CONSTEXPR typename std::enable_if<
|
|
std::is_signed<T>::value,
|
|
int
|
|
>::type
|
|
clz(T n) {
|
|
return sprout::detail::clz(static_cast<typename std::make_unsigned<T>::type>(n));
|
|
}
|
|
} // namespace detail
|
|
//
|
|
// clz
|
|
//
|
|
template<typename T>
|
|
inline SPROUT_CONSTEXPR typename std::enable_if<
|
|
std::is_integral<T>::value,
|
|
int
|
|
>::type
|
|
clz(T n) {
|
|
return sprout::detail::clz(n);
|
|
}
|
|
} // namespace sprout
|
|
|
|
#endif // #ifndef SPROUT_BIT_CLZ_HPP
|