| // -*- C++ -*- |
| //===------------------------------ bit ----------------------------------===// |
| // |
| // 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.pow.two], integral powers of 2 |
| template <class T> |
| constexpr bool ispow2(T x) noexcept; // C++20 |
| template <class T> |
| constexpr T ceil2(T x); // C++20 |
| template <class T> |
| constexpr T floor2(T x) noexcept; // C++20 |
| template <class T> |
| constexpr T log2p1(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 <__config> |
| #include <limits> |
| #include <type_traits> |
| #include <version> |
| #include <__debug> |
| |
| #if defined(__IBMCPP__) |
| #include "support/ibm/support.h" |
| #endif |
| #if defined(_LIBCPP_COMPILER_MSVC) |
| #include <intrin.h> |
| #endif |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #ifndef _LIBCPP_COMPILER_MSVC |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_ctz(unsigned __x) _NOEXCEPT { return __builtin_ctz(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_ctz(unsigned long __x) _NOEXCEPT { return __builtin_ctzl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); } |
| |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(unsigned __x) _NOEXCEPT { return __builtin_clz(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(unsigned long __x) _NOEXCEPT { return __builtin_clzl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_clz(unsigned long long __x) _NOEXCEPT { return __builtin_clzll(__x); } |
| |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_popcount(unsigned __x) _NOEXCEPT { return __builtin_popcount(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_popcount(unsigned long __x) _NOEXCEPT { return __builtin_popcountl(__x); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { return __builtin_popcountll(__x); } |
| |
| #else // _LIBCPP_COMPILER_MSVC |
| |
| // Precondition: __x != 0 |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __libcpp_ctz(unsigned __x) { |
| static_assert(sizeof(unsigned) == sizeof(unsigned long), ""); |
| static_assert(sizeof(unsigned long) == 4, ""); |
| unsigned long __where; |
| if (_BitScanForward(&__where, __x)) |
| return static_cast<int>(__where); |
| return 32; |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __libcpp_ctz(unsigned long __x) { |
| static_assert(sizeof(unsigned long) == sizeof(unsigned), ""); |
| return __ctz(static_cast<unsigned>(__x)); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __libcpp_ctz(unsigned long long __x) { |
| unsigned long __where; |
| #if defined(_LIBCPP_HAS_BITSCAN64) |
| (defined(_M_AMD64) || defined(__x86_64__)) |
| if (_BitScanForward64(&__where, __x)) |
| return static_cast<int>(__where); |
| #else |
| // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls. |
| if (_BitScanForward(&__where, static_cast<unsigned long>(__x))) |
| return static_cast<int>(__where); |
| if (_BitScanForward(&__where, static_cast<unsigned long>(__x >> 32))) |
| return static_cast<int>(__where + 32); |
| #endif |
| return 64; |
| } |
| |
| // Precondition: __x != 0 |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __libcpp_clz(unsigned __x) { |
| static_assert(sizeof(unsigned) == sizeof(unsigned long), ""); |
| static_assert(sizeof(unsigned long) == 4, ""); |
| unsigned long __where; |
| if (_BitScanReverse(&__where, __x)) |
| return static_cast<int>(31 - __where); |
| return 32; // Undefined Behavior. |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __libcpp_clz(unsigned long __x) { |
| static_assert(sizeof(unsigned) == sizeof(unsigned long), ""); |
| return __libcpp_clz(static_cast<unsigned>(__x)); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| int __libcpp_clz(unsigned long long __x) { |
| unsigned long __where; |
| #if defined(_LIBCPP_HAS_BITSCAN64) |
| if (_BitScanReverse64(&__where, __x)) |
| return static_cast<int>(63 - __where); |
| #else |
| // Win32 doesn't have _BitScanReverse64 so emulate it with two 32 bit calls. |
| if (_BitScanReverse(&__where, static_cast<unsigned long>(__x >> 32))) |
| return static_cast<int>(63 - (__where + 32)); |
| if (_BitScanReverse(&__where, static_cast<unsigned long>(__x))) |
| return static_cast<int>(63 - __where); |
| #endif |
| return 64; // Undefined Behavior. |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned __x) { |
| static_assert(sizeof(unsigned) == 4, ""); |
| return __popcnt(__x); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long __x) { |
| static_assert(sizeof(unsigned long) == 4, ""); |
| return __popcnt(__x); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long long __x) { |
| static_assert(sizeof(unsigned long long) == 8, ""); |
| return __popcnt64(__x); |
| } |
| |
| #endif // _LIBCPP_COMPILER_MSVC |
| |
| template <class _Tp> |
| using __bitop_unsigned_integer _LIBCPP_NODEBUG_TYPE = integral_constant<bool, |
| is_integral<_Tp>::value && |
| is_unsigned<_Tp>::value && |
| _IsNotSame<typename remove_cv<_Tp>::type, bool>::value && |
| _IsNotSame<typename remove_cv<_Tp>::type, signed char>::value && |
| _IsNotSame<typename remove_cv<_Tp>::type, wchar_t>::value && |
| _IsNotSame<typename remove_cv<_Tp>::type, char16_t>::value && |
| _IsNotSame<typename remove_cv<_Tp>::type, char32_t>::value |
| >; |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| _Tp __rotl(_Tp __t, unsigned int __cnt) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__rotl requires unsigned"); |
| 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_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| _Tp __rotr(_Tp __t, unsigned int __cnt) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__rotr requires unsigned"); |
| 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_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| int __countr_zero(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__countr_zero requires unsigned"); |
| if (__t == 0) |
| return numeric_limits<_Tp>::digits; |
| |
| if (sizeof(_Tp) <= sizeof(unsigned int)) |
| return __libcpp_ctz(static_cast<unsigned int>(__t)); |
| else if (sizeof(_Tp) <= sizeof(unsigned long)) |
| return __libcpp_ctz(static_cast<unsigned long>(__t)); |
| else if (sizeof(_Tp) <= sizeof(unsigned long long)) |
| return __libcpp_ctz(static_cast<unsigned long long>(__t)); |
| else |
| { |
| int __ret = 0; |
| int __iter = 0; |
| const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits; |
| while ((__iter = __libcpp_ctz(static_cast<unsigned long long>(__t))) == __ulldigits) |
| { |
| __ret += __iter; |
| __t >>= __ulldigits; |
| } |
| return __ret + __iter; |
| } |
| } |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| int __countl_zero(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__countl_zero requires unsigned"); |
| if (__t == 0) |
| return numeric_limits<_Tp>::digits; |
| |
| if (sizeof(_Tp) <= sizeof(unsigned int)) |
| return __libcpp_clz(static_cast<unsigned int>(__t)) |
| - (numeric_limits<unsigned int>::digits - numeric_limits<_Tp>::digits); |
| else if (sizeof(_Tp) <= sizeof(unsigned long)) |
| return __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 __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 = __rotr(__t, __ulldigits); |
| if ((__iter = __countl_zero(static_cast<unsigned long long>(__t))) != __ulldigits) |
| break; |
| __ret += __iter; |
| } |
| return __ret + __iter; |
| } |
| } |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| int __countl_one(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__countl_one requires unsigned"); |
| return __t != numeric_limits<_Tp>::max() |
| ? __countl_zero(static_cast<_Tp>(~__t)) |
| : numeric_limits<_Tp>::digits; |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| int __countr_one(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__countr_one requires unsigned"); |
| return __t != numeric_limits<_Tp>::max() |
| ? __countr_zero(static_cast<_Tp>(~__t)) |
| : numeric_limits<_Tp>::digits; |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| int |
| __popcount(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__libcpp_popcount requires unsigned"); |
| if (sizeof(_Tp) <= sizeof(unsigned int)) |
| return __libcpp_popcount(static_cast<unsigned int>(__t)); |
| else if (sizeof(_Tp) <= sizeof(unsigned long)) |
| return __libcpp_popcount(static_cast<unsigned long>(__t)); |
| else if (sizeof(_Tp) <= sizeof(unsigned long long)) |
| return __libcpp_popcount(static_cast<unsigned long long>(__t)); |
| else |
| { |
| int __ret = 0; |
| while (__t != 0) |
| { |
| __ret += __libcpp_popcount(static_cast<unsigned long long>(__t)); |
| __t >>= numeric_limits<unsigned long long>::digits; |
| } |
| return __ret; |
| } |
| } |
| |
| |
| // integral log base 2 |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 |
| unsigned __bit_log2(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__bit_log2 requires unsigned"); |
| return std::numeric_limits<_Tp>::digits - 1 - __countl_zero(__t); |
| } |
| |
| template <class _Tp> |
| _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR |
| bool __ispow2(_Tp __t) _NOEXCEPT |
| { |
| static_assert(__bitop_unsigned_integer<_Tp>::value, "__ispow2 requires unsigned"); |
| return __t != 0 && (((__t & (__t - 1)) == 0)); |
| } |
| |
| |
| #if _LIBCPP_STD_VER > 17 |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp> |
| rotl(_Tp __t, unsigned int __cnt) noexcept |
| { |
| return __rotl(__t, __cnt); |
| } |
| |
| |
| // rotr |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp> |
| rotr(_Tp __t, unsigned int __cnt) noexcept |
| { |
| return __rotr(__t, __cnt); |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, int> |
| countl_zero(_Tp __t) noexcept |
| { |
| return __countl_zero(__t); |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, int> |
| countl_one(_Tp __t) noexcept |
| { |
| return __countl_one(__t); |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, int> |
| countr_zero(_Tp __t) noexcept |
| { |
| return __countr_zero(__t); |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, int> |
| countr_one(_Tp __t) noexcept |
| { |
| return __countr_one(__t); |
| } |
| |
| |
| template<class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, int> |
| popcount(_Tp __t) noexcept |
| { |
| return __popcount(__t); |
| } |
| |
| |
| template <class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, bool> |
| ispow2(_Tp __t) noexcept |
| { |
| return __ispow2(__t); |
| } |
| |
| template <class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp> |
| floor2(_Tp __t) noexcept |
| { |
| return __t == 0 ? 0 : _Tp{1} << __bit_log2(__t); |
| } |
| |
| template <class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp> |
| ceil2(_Tp __t) noexcept |
| { |
| if (__t < 2) return 1; |
| const unsigned __n = numeric_limits<_Tp>::digits - countl_zero((_Tp)(__t - 1u)); |
| _LIBCPP_DEBUG_ASSERT(__libcpp_is_constant_evaluated() || __n != numeric_limits<_Tp>::digits, "Bad input to ceil2"); |
| |
| 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 <class _Tp> |
| _LIBCPP_INLINE_VISIBILITY constexpr |
| enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp> |
| log2p1(_Tp __t) noexcept |
| { |
| return __t == 0 ? 0 : __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 |
| |
| #endif // _LIBCPP_BIT |