| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // 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 |
| #define _LIBCPP_BIT |
| |
| /* |
| bit synopsis |
| |
| namespace std { |
| // [bit.cast], bit_cast |
| template<class To, class From> |
| constexpr To bit_cast(const From& from) noexcept; // C++20 |
| |
| // [bit.byteswap], byteswap |
| template<class T> |
| constexpr T byteswap(T value) noexcept; // C++23 |
| |
| // [bit.pow.two], integral powers of 2 |
| template <class T> |
| constexpr bool has_single_bit(T x) noexcept; // C++20 |
| template <class T> |
| constexpr T bit_ceil(T x); // C++20 |
| template <class T> |
| constexpr T bit_floor(T x) noexcept; // C++20 |
| template <class T> |
| constexpr int bit_width(T x) noexcept; // C++20 |
| |
| // [bit.rotate], rotating |
| template<class T> |
| constexpr T rotl(T x, unsigned int s) noexcept; // C++20 |
| template<class T> |
| constexpr T rotr(T x, unsigned int s) noexcept; // C++20 |
| |
| // [bit.count], counting |
| template<class T> |
| constexpr int countl_zero(T x) noexcept; // C++20 |
| template<class T> |
| constexpr int countl_one(T x) noexcept; // C++20 |
| template<class T> |
| constexpr int countr_zero(T x) noexcept; // C++20 |
| template<class T> |
| constexpr int countr_one(T x) noexcept; // C++20 |
| template<class T> |
| constexpr int popcount(T x) noexcept; // C++20 |
| |
| // [bit.endian], endian |
| enum class endian { |
| little = see below, // C++20 |
| big = see below, // C++20 |
| native = see below // C++20 |
| }; |
| |
| } // namespace std |
| |
| */ |
| |
| #include <__assert> // all public C++ headers provide the assertion handler |
| #include <__bit/bit_cast.h> |
| #include <__bit/byteswap.h> |
| #include <__bits> // __libcpp_clz |
| #include <__concepts/arithmetic.h> |
| #include <__config> |
| #include <limits> |
| #include <type_traits> |
| #include <version> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template<class _Tp> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| _Tp __rotr(_Tp __t, unsigned int __cnt) _NOEXCEPT |
| { |
| static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type"); |
| const unsigned int __dig = numeric_limits<_Tp>::digits; |
| if ((__cnt % __dig) == 0) |
| return __t; |
| return (__t >> (__cnt % __dig)) | (__t << (__dig - (__cnt % __dig))); |
| } |
| |
| template<class _Tp> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 |
| int __countl_zero(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_zero requires an unsigned integer type"); |
| if (__t == 0) |
| return numeric_limits<_Tp>::digits; |
| |
| if (sizeof(_Tp) <= sizeof(unsigned int)) |
| return std::__libcpp_clz(static_cast<unsigned int>(__t)) |
| - (numeric_limits<unsigned int>::digits - numeric_limits<_Tp>::digits); |
| else if (sizeof(_Tp) <= sizeof(unsigned long)) |
| return std::__libcpp_clz(static_cast<unsigned long>(__t)) |
| - (numeric_limits<unsigned long>::digits - numeric_limits<_Tp>::digits); |
| else if (sizeof(_Tp) <= sizeof(unsigned long long)) |
| return std::__libcpp_clz(static_cast<unsigned long long>(__t)) |
| - (numeric_limits<unsigned long long>::digits - numeric_limits<_Tp>::digits); |
| else |
| { |
| int __ret = 0; |
| int __iter = 0; |
| const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits; |
| while (true) { |
| __t = std::__rotr(__t, __ulldigits); |
| if ((__iter = std::__countl_zero(static_cast<unsigned long long>(__t))) != __ulldigits) |
| break; |
| __ret += __iter; |
| } |
| return __ret + __iter; |
| } |
| } |
| |
| #if _LIBCPP_STD_VER > 17 |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotl(_Tp __t, unsigned int __cnt) noexcept { |
| const unsigned int __dig = numeric_limits<_Tp>::digits; |
| if ((__cnt % __dig) == 0) |
| return __t; |
| return (__t << (__cnt % __dig)) | (__t >> (__dig - (__cnt % __dig))); |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp rotr(_Tp __t, unsigned int __cnt) noexcept { |
| return std::__rotr(__t, __cnt); |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr int countl_zero(_Tp __t) noexcept { |
| return std::__countl_zero(__t); |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr int countl_one(_Tp __t) noexcept { |
| return __t != numeric_limits<_Tp>::max() ? std::countl_zero(static_cast<_Tp>(~__t)) : numeric_limits<_Tp>::digits; |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _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_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; |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr int popcount(_Tp __t) noexcept { |
| if (sizeof(_Tp) <= sizeof(unsigned int)) |
| return std::__libcpp_popcount(static_cast<unsigned int>(__t)); |
| else if (sizeof(_Tp) <= sizeof(unsigned long)) |
| return std::__libcpp_popcount(static_cast<unsigned long>(__t)); |
| else if (sizeof(_Tp) <= sizeof(unsigned long long)) |
| return std::__libcpp_popcount(static_cast<unsigned long long>(__t)); |
| else { |
| int __ret = 0; |
| while (__t != 0) { |
| __ret += std::__libcpp_popcount(static_cast<unsigned long long>(__t)); |
| __t >>= numeric_limits<unsigned long long>::digits; |
| } |
| return __ret; |
| } |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr bool has_single_bit(_Tp __t) noexcept { |
| return __t != 0 && (((__t & (__t - 1)) == 0)); |
| } |
| |
| // integral log base 2 |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp __bit_log2(_Tp __t) noexcept { |
| return numeric_limits<_Tp>::digits - 1 - std::countl_zero(__t); |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_floor(_Tp __t) noexcept { |
| return __t == 0 ? 0 : _Tp{1} << std::__bit_log2(__t); |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp bit_ceil(_Tp __t) noexcept { |
| if (__t < 2) |
| return 1; |
| const unsigned __n = numeric_limits<_Tp>::digits - std::countl_zero((_Tp)(__t - 1u)); |
| _LIBCPP_ASSERT(__n != numeric_limits<_Tp>::digits, "Bad input to bit_ceil"); |
| |
| if constexpr (sizeof(_Tp) >= sizeof(unsigned)) |
| return _Tp{1} << __n; |
| else { |
| const unsigned __extra = numeric_limits<unsigned>::digits - numeric_limits<_Tp>::digits; |
| const unsigned __retVal = 1u << (__n + __extra); |
| return (_Tp)(__retVal >> __extra); |
| } |
| } |
| |
| template <__libcpp_unsigned_integer _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr int bit_width(_Tp __t) noexcept { |
| return __t == 0 ? 0 : std::__bit_log2(__t) + 1; |
| } |
| |
| enum class endian { |
| little = 0xDEAD, |
| big = 0xFACE, |
| # if defined(_LIBCPP_LITTLE_ENDIAN) |
| native = little |
| # elif defined(_LIBCPP_BIG_ENDIAN) |
| native = big |
| # else |
| native = 0xCAFE |
| # endif |
| }; |
| |
| #endif // _LIBCPP_STD_VER > 17 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 |
| # include <iosfwd> |
| #endif |
| |
| #endif // _LIBCPP_BIT |
