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https://github.com/bolero-MURAKAMI/Sprout.git
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50 lines
1.3 KiB
C++
50 lines
1.3 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_CLRSB_HPP
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#define SPROUT_BIT_CLRSB_HPP
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/bit/clz.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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clrsb(unsigned x) {
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return __builtin_clrsb(x);
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}
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inline SPROUT_CONSTEXPR int
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clrsb(unsigned long x) {
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return __builtin_clrsbl(x);
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}
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inline SPROUT_CONSTEXPR int
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clrsb(unsigned long long x) {
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return __builtin_clrsbll(x);
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}
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# endif
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template<typename Integral>
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inline SPROUT_CONSTEXPR int
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clrsb(Integral x) {
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return sprout::clz(~x);
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}
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} // namespace detail
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//
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// clrsb
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//
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template<typename Integral>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_integral<Integral>::value,
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int
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>::type
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clrsb(Integral x) {
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return sprout::detail::clrsb(x);
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_BIT_CLRSB_HPP
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