mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-14 10:39:05 +00:00
75 lines
2.1 KiB
C++
75 lines
2.1 KiB
C++
/*=============================================================================
|
|
Copyright (c) 2011-2014 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_non0(unsigned x) {
|
|
return __builtin_clz(x);
|
|
}
|
|
inline SPROUT_CONSTEXPR int
|
|
clz_non0(unsigned long x) {
|
|
return __builtin_clzl(x);
|
|
}
|
|
inline SPROUT_CONSTEXPR int
|
|
clz_non0(unsigned long long x) {
|
|
return __builtin_clzll(x);
|
|
}
|
|
# endif
|
|
template<typename Integral>
|
|
inline SPROUT_CONSTEXPR int
|
|
clz_non0_impl(Integral x, Integral m = Integral(1) << (CHAR_BIT * sizeof(Integral) - 1)) {
|
|
return m == 0 || x & m ? 0
|
|
: 1 + sprout::detail::clz_non0_impl(x, static_cast<Integral>(m >> 1))
|
|
;
|
|
}
|
|
template<typename Integral>
|
|
inline SPROUT_CONSTEXPR typename std::enable_if<
|
|
std::is_unsigned<Integral>::value,
|
|
int
|
|
>::type
|
|
clz_non0(Integral x) {
|
|
return sprout::detail::clz_non0_impl(static_cast<Integral>(x));
|
|
}
|
|
template<typename Integral>
|
|
inline SPROUT_CONSTEXPR typename std::enable_if<
|
|
std::is_signed<Integral>::value,
|
|
int
|
|
>::type
|
|
clz_non0(Integral x) {
|
|
return sprout::detail::clz_non0(static_cast<typename std::make_unsigned<Integral>::type>(x));
|
|
}
|
|
template<typename Integral>
|
|
inline SPROUT_CONSTEXPR int
|
|
clz(Integral x) {
|
|
return x == 0 ? static_cast<int>(sizeof(x) * CHAR_BIT)
|
|
: sprout::detail::clz_non0(x)
|
|
;
|
|
}
|
|
} // namespace detail
|
|
//
|
|
// clz
|
|
//
|
|
template<typename Integral>
|
|
inline SPROUT_CONSTEXPR typename std::enable_if<
|
|
std::is_integral<Integral>::value,
|
|
int
|
|
>::type
|
|
clz(Integral x) {
|
|
return sprout::detail::clz(x);
|
|
}
|
|
} // namespace sprout
|
|
|
|
#endif // #ifndef SPROUT_BIT_CLZ_HPP
|