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// <bit> -*- C++ -*-
// Copyright (C) 2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/bit
* This is a Standard C++ Library header.
*/
#ifndef _GLIBCXX_BIT
#define _GLIBCXX_BIT 1
#pragma GCC system_header
#if __cplusplus >= 201402L
#include <type_traits>
#include <limits>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Tp>
constexpr _Tp
__rotl(_Tp __x, unsigned int __s) noexcept
{
constexpr auto _Nd = numeric_limits<_Tp>::digits;
const unsigned __sN = __s % _Nd;
return (__x << __sN) | (__x >> ((-__sN) % _Nd));
}
template<typename _Tp>
constexpr _Tp
__rotr(_Tp __x, unsigned int __s) noexcept
{
constexpr auto _Nd = numeric_limits<_Tp>::digits;
const unsigned __sN = __s % _Nd;
return (__x >> __sN) | (__x << ((-__sN) % _Nd));
}
template<typename _Tp>
constexpr int
__countl_zero(_Tp __x) noexcept
{
using __limits = numeric_limits<_Tp>;
if (__x == 0)
return __limits::digits;
using __limits_ull = numeric_limits<unsigned long long>;
using __limits_ul = numeric_limits<unsigned long>;
using __limits_u = numeric_limits<unsigned>;
if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_u::digits)
{
constexpr int __diff = __limits_u::digits - __limits::digits;
return __builtin_clz(__x) - __diff;
}
else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ul::digits)
{
constexpr int __diff = __limits_ul::digits - __limits::digits;
return __builtin_clzl(__x) - __diff;
}
else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ull::digits)
{
constexpr int __diff = __limits_ull::digits - __limits::digits;
return __builtin_clzll(__x) - __diff;
}
else // (__limits::digits > __limits_ull::digits)
{
static_assert(__limits::digits <= (2 * __limits_ull::digits),
"Maximum supported integer size is 128-bit");
unsigned long long __high = __x >> __limits_ull::digits;
if (__high != 0)
{
constexpr int __diff
= (2 * __limits_ull::digits) - __limits::digits;
return __builtin_clzll(__high) - __diff;
}
unsigned long long __low = __x & __limits_ull::max();
return (__limits::digits - __limits_ull::digits)
+ __builtin_clzll(__low);
}
}
template<typename _Tp>
constexpr int
__countl_one(_Tp __x) noexcept
{
if (__x == numeric_limits<_Tp>::max())
return numeric_limits<_Tp>::digits;
return std::__countl_zero<_Tp>((_Tp)~__x);
}
template<typename _Tp>
constexpr int
__countr_zero(_Tp __x) noexcept
{
using __limits = numeric_limits<_Tp>;
if (__x == 0)
return __limits::digits;
using __limits_ull = numeric_limits<unsigned long long>;
using __limits_ul = numeric_limits<unsigned long>;
using __limits_u = numeric_limits<unsigned>;
if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_u::digits)
return __builtin_ctz(__x);
else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ul::digits)
return __builtin_ctzl(__x);
else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ull::digits)
return __builtin_ctzll(__x);
else // (__limits::digits > __limits_ull::digits)
{
static_assert(__limits::digits <= (2 * __limits_ull::digits),
"Maximum supported integer size is 128-bit");
unsigned long long __low = __x & __limits_ull::max();
if (__low != 0)
return __builtin_ctzll(__low);
unsigned long long __high = __x >> __limits_ull::digits;
return __builtin_ctzll(__high) + __limits_ull::digits;
}
}
template<typename _Tp>
constexpr int
__countr_one(_Tp __x) noexcept
{
if (__x == numeric_limits<_Tp>::max())
return numeric_limits<_Tp>::digits;
return std::__countr_zero((_Tp)~__x);
}
template<typename _Tp>
constexpr int
__popcount(_Tp __x) noexcept
{
using __limits = numeric_limits<_Tp>;
if (__x == 0)
return 0;
using __limits_ull = numeric_limits<unsigned long long>;
using __limits_ul = numeric_limits<unsigned long>;
using __limits_u = numeric_limits<unsigned>;
if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_u::digits)
return __builtin_popcount(__x);
else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ul::digits)
return __builtin_popcountl(__x);
else if _GLIBCXX17_CONSTEXPR (__limits::digits <= __limits_ull::digits)
return __builtin_popcountll(__x);
else // (__limits::digits > __limits_ull::digits)
{
static_assert(__limits::digits <= (2 * __limits_ull::digits),
"Maximum supported integer size is 128-bit");
unsigned long long __low = __x & __limits_ull::max();
unsigned long long __high = __x >> __limits_ull::digits;
return __builtin_popcountll(__low) + __builtin_popcountll(__high);
}
}
template<typename _Tp>
constexpr bool
__ispow2(_Tp __x) noexcept
{ return std::__popcount(__x) == 1; }
template<typename _Tp>
constexpr _Tp
__ceil2(_Tp __x) noexcept
{
constexpr auto _Nd = numeric_limits<_Tp>::digits;
if (__x == 0)
return 1;
return (_Tp)1u << (_Nd - std::__countl_zero((_Tp)(__x - 1u)));
}
template<typename _Tp>
constexpr _Tp
__floor2(_Tp __x) noexcept
{
constexpr auto _Nd = numeric_limits<_Tp>::digits;
if (__x == 0)
return 0;
return (_Tp)1u << (_Nd - std::__countl_zero((_Tp)(__x >> 1)));
}
template<typename _Tp>
constexpr _Tp
__log2p1(_Tp __x) noexcept
{
constexpr auto _Nd = numeric_limits<_Tp>::digits;
if (__x == 0)
return 0;
return _Nd - std::__countl_zero(__x);
}
#if __cplusplus > 201703L
template<typename _Tp, typename _Up, bool = is_integral_v<_Tp>>
struct _If_is_unsigned_integer_type { };
template<typename _Up>
struct _If_is_unsigned_integer_type<bool, _Up, true> { };
template<typename _Tp, typename _Up>
struct _If_is_unsigned_integer_type<_Tp, _Up, true>
: enable_if<is_same_v<_Tp, make_unsigned_t<_Tp>>, _Up> { };
template<typename _Tp, typename _Up = _Tp>
using _If_is_unsigned_integer
= typename _If_is_unsigned_integer_type<remove_cv_t<_Tp>, _Up>::type;
#if ! __STRICT_ANSI__
// [bitops.rot], rotating
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp>
rotl(_Tp __x, unsigned int __s) noexcept
{ return std::__rotl(__x, __s); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp>
rotr(_Tp __x, unsigned int __s) noexcept
{ return std::__rotr(__x, __s); }
// [bitops.count], counting
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp, int>
countl_zero(_Tp __x) noexcept
{ return std::__countl_zero(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp, int>
countl_one(_Tp __x) noexcept
{ return std::__countl_one(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp, int>
countr_zero(_Tp __x) noexcept
{ return std::__countr_zero(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp, int>
countr_one(_Tp __x) noexcept
{ return std::__countr_one(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp, int>
popcount(_Tp __x) noexcept
{ return std::__popcount(__x); }
#endif
// Integral power-of-two operations
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp, bool>
ispow2(_Tp __x) noexcept
{ return std::__ispow2(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp>
ceil2(_Tp __x) noexcept
{ return std::__ceil2(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp>
floor2(_Tp __x) noexcept
{ return std::__floor2(__x); }
template<typename _Tp>
constexpr _If_is_unsigned_integer<_Tp>
log2p1(_Tp __x) noexcept
{ return std::__log2p1(__x); }
#if ! __STRICT_ANSI__
enum class byte : unsigned char;
constexpr byte
rotl(byte __x, unsigned int __s) noexcept
{ return (byte)std::__rotl((unsigned char)__x, __s); }
constexpr byte
rotr(byte __x, unsigned int __s) noexcept
{ return (byte)std::__rotr((unsigned char)__x, __s); }
constexpr int
countl_zero(byte __x) noexcept
{ return std::__countl_zero((unsigned char)__x); }
constexpr int
countl_one(byte __x) noexcept
{ return std::__countl_one((unsigned char)__x); }
constexpr int
countr_zero(byte __x) noexcept
{ return std::__countr_zero((unsigned char)__x); }
constexpr int
countr_one(byte __x) noexcept
{ return std::__countr_one((unsigned char)__x); }
constexpr int
popcount(byte __x) noexcept
{ return std::__popcount((unsigned char)__x); }
constexpr bool
ispow2(byte __x) noexcept
{ return std::__ispow2((unsigned char)__x); }
constexpr byte
ceil2(byte __x) noexcept
{ return (byte)std::__ceil2((unsigned char)__x); }
constexpr byte
floor2(byte __x) noexcept
{ return (byte)std::__floor2((unsigned char)__x); }
constexpr byte
log2p1(byte __x) noexcept
{ return (byte)std::__log2p1((unsigned char)__x); }
#endif
#endif // C++2a
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++14
#endif // _GLIBCXX_BIT
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