1//===----------------------------------------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8 9#ifndef _LIBCPP___BIT_COUNTR_H 10#define _LIBCPP___BIT_COUNTR_H 11 12#include <__bit/rotate.h> 13#include <__concepts/arithmetic.h> 14#include <__config> 15#include <limits> 16 17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 18# pragma GCC system_header 19#endif 20 21_LIBCPP_PUSH_MACROS 22#include <__undef_macros> 23 24_LIBCPP_BEGIN_NAMESPACE_STD 25 26inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 27int __libcpp_ctz(unsigned __x) _NOEXCEPT { return __builtin_ctz(__x); } 28 29inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 30int __libcpp_ctz(unsigned long __x) _NOEXCEPT { return __builtin_ctzl(__x); } 31 32inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 33int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); } 34 35#if _LIBCPP_STD_VER >= 20 36 37template <__libcpp_unsigned_integer _Tp> 38_LIBCPP_HIDE_FROM_ABI constexpr int countr_zero(_Tp __t) noexcept { 39 if (__t == 0) 40 return numeric_limits<_Tp>::digits; 41 42 if (sizeof(_Tp) <= sizeof(unsigned int)) 43 return std::__libcpp_ctz(static_cast<unsigned int>(__t)); 44 else if (sizeof(_Tp) <= sizeof(unsigned long)) 45 return std::__libcpp_ctz(static_cast<unsigned long>(__t)); 46 else if (sizeof(_Tp) <= sizeof(unsigned long long)) 47 return std::__libcpp_ctz(static_cast<unsigned long long>(__t)); 48 else { 49 int __ret = 0; 50 const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits; 51 while (static_cast<unsigned long long>(__t) == 0uLL) { 52 __ret += __ulldigits; 53 __t >>= __ulldigits; 54 } 55 return __ret + std::__libcpp_ctz(static_cast<unsigned long long>(__t)); 56 } 57} 58 59template <__libcpp_unsigned_integer _Tp> 60_LIBCPP_HIDE_FROM_ABI constexpr int countr_one(_Tp __t) noexcept { 61 return __t != numeric_limits<_Tp>::max() ? std::countr_zero(static_cast<_Tp>(~__t)) : numeric_limits<_Tp>::digits; 62} 63 64#endif // _LIBCPP_STD_VER >= 20 65 66_LIBCPP_END_NAMESPACE_STD 67 68_LIBCPP_POP_MACROS 69 70#endif // _LIBCPP___BIT_COUNTR_H 71