mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2014 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_BIT_CLZ_HPP
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#define SPROUT_BIT_CLZ_HPP
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#include <climits>
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#include <type_traits>
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#include <sprout/config.hpp>
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namespace sprout {
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namespace detail {
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# if SPROUT_USE_BUILTIN_BIT_OPERATION
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inline SPROUT_CONSTEXPR int
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clz(unsigned n) {
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return __builtin_clz(n);
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}
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inline SPROUT_CONSTEXPR int
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clz(unsigned long n) {
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return __builtin_clzl(n);
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}
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inline SPROUT_CONSTEXPR int
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clz(unsigned long long n) {
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return __builtin_clzll(n);
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}
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# endif
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template<typename T>
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inline SPROUT_CONSTEXPR int
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clz_impl(T n, T m = T(1) << (CHAR_BIT * sizeof(T) - 1)) {
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return m == 0 || n & m ? 0
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: 1 + sprout::detail::clz_impl(n, static_cast<T>(m >> 1))
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_unsigned<T>::value,
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int
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>::type
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clz(T n) {
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return sprout::detail::clz_impl(static_cast<T>(n));
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}
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template<typename T>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_signed<T>::value,
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int
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>::type
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clz(T n) {
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return sprout::detail::clz(static_cast<typename std::make_unsigned<T>::type>(n));
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}
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} // namespace detail
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//
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// clz
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//
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template<typename T>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_integral<T>::value,
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int
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>::type
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clz(T n) {
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return sprout::detail::clz(n);
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_BIT_CLZ_HPP
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