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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___BIT_COUNTR_H
#define _LIBCPP___BIT_COUNTR_H
#include <__bit/rotate.h>
#include <__concepts/arithmetic.h>
#include <__config>
#include <limits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned __x) _NOEXCEPT { return __builtin_ctz(__x); }
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned long __x) _NOEXCEPT { return __builtin_ctzl(__x); }
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); }
#if _LIBCPP_STD_VER >= 20
template <__libcpp_unsigned_integer _Tp>
_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int countr_zero(_Tp __t) noexcept {
if (__t == 0)
return numeric_limits<_Tp>::digits;
if (sizeof(_Tp) <= sizeof(unsigned int))
return std::__libcpp_ctz(static_cast<unsigned int>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long))
return std::__libcpp_ctz(static_cast<unsigned long>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long long))
return std::__libcpp_ctz(static_cast<unsigned long long>(__t));
else {
int __ret = 0;
const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
while (static_cast<unsigned long long>(__t) == 0uLL) {
__ret += __ulldigits;
__t >>= __ulldigits;
}
return __ret + std::__libcpp_ctz(static_cast<unsigned long long>(__t));
}
}
template <__libcpp_unsigned_integer _Tp>
_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr int countr_one(_Tp __t) noexcept {
return __t != numeric_limits<_Tp>::max() ? std::countr_zero(static_cast<_Tp>(~__t)) : numeric_limits<_Tp>::digits;
}
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___BIT_COUNTR_H
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