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|
// -*- 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 <__config>
#include <limits>
#include <type_traits>
#include <version>
#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
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp __rotl(_Tp __t, unsigned int __cnt) _NOEXCEPT
{
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotl 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_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_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_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countr_zero(_Tp __t) _NOEXCEPT
{
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countr_zero requires an unsigned integer type");
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;
const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
while (static_cast<unsigned long long>(__t) == 0uLL)
{
__ret += __ulldigits;
__t >>= __ulldigits;
}
return __ret + __libcpp_ctz(static_cast<unsigned long long>(__t));
}
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
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 __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(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_one requires an unsigned integer type");
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(__libcpp_is_unsigned_integer<_Tp>::value, "__countr_one requires an unsigned integer type");
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(__libcpp_is_unsigned_integer<_Tp>::value, "__popcount requires an unsigned integer type");
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(__libcpp_is_unsigned_integer<_Tp>::value, "__bit_log2 requires an unsigned integer type");
return numeric_limits<_Tp>::digits - 1 - __countl_zero(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
bool __has_single_bit(_Tp __t) _NOEXCEPT
{
static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__has_single_bit requires an unsigned integer type");
return __t != 0 && (((__t & (__t - 1)) == 0));
}
#if _LIBCPP_STD_VER > 17
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
rotl(_Tp __t, unsigned int __cnt) noexcept
{
return __rotl(__t, __cnt);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_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<__libcpp_is_unsigned_integer<_Tp>::value, int>
countl_zero(_Tp __t) noexcept
{
return __countl_zero(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
countl_one(_Tp __t) noexcept
{
return __countl_one(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
countr_zero(_Tp __t) noexcept
{
return __countr_zero(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
countr_one(_Tp __t) noexcept
{
return __countr_one(__t);
}
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
popcount(_Tp __t) noexcept
{
return __popcount(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, bool>
has_single_bit(_Tp __t) noexcept
{
return __has_single_bit(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
bit_floor(_Tp __t) noexcept
{
return __t == 0 ? 0 : _Tp{1} << __bit_log2(__t);
}
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
bit_ceil(_Tp __t) noexcept
{
if (__t < 2) return 1;
const unsigned __n = numeric_limits<_Tp>::digits - 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 <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
bit_width(_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
|
