xref: /llvm-project-15.0.7/libcxx/include/bitset (revision b4e88d4d)

// -*- C++ -*-
//===---------------------------- bitset ----------------------------------===//
//
// 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_BITSET
#define _LIBCPP_BITSET

/*
    bitset synopsis

namespace std
{

namespace std {

template <size_t N>
class bitset
{
public:
    // bit reference:
    class reference
    {
        friend class bitset;
        reference() noexcept;
    public:
        ~reference() noexcept;
        reference& operator=(bool x) noexcept;           // for b[i] = x;
        reference& operator=(const reference&) noexcept; // for b[i] = b[j];
        bool operator~() const noexcept;                 // flips the bit
        operator bool() const noexcept;                  // for x = b[i];
        reference& flip() noexcept;                      // for b[i].flip();
    };

    // 23.3.5.1 constructors:
    constexpr bitset() noexcept;
    constexpr bitset(unsigned long long val) noexcept;
    template <class charT>
        explicit bitset(const charT* str,
                        typename basic_string<charT>::size_type n = basic_string<charT>::npos,
                        charT zero = charT('0'), charT one = charT('1'));
    template<class charT, class traits, class Allocator>
        explicit bitset(const basic_string<charT,traits,Allocator>& str,
                        typename basic_string<charT,traits,Allocator>::size_type pos = 0,
                        typename basic_string<charT,traits,Allocator>::size_type n =
                                 basic_string<charT,traits,Allocator>::npos,
                        charT zero = charT('0'), charT one = charT('1'));

    // 23.3.5.2 bitset operations:
    bitset& operator&=(const bitset& rhs) noexcept;
    bitset& operator|=(const bitset& rhs) noexcept;
    bitset& operator^=(const bitset& rhs) noexcept;
    bitset& operator<<=(size_t pos) noexcept;
    bitset& operator>>=(size_t pos) noexcept;
    bitset& set() noexcept;
    bitset& set(size_t pos, bool val = true);
    bitset& reset() noexcept;
    bitset& reset(size_t pos);
    bitset operator~() const noexcept;
    bitset& flip() noexcept;
    bitset& flip(size_t pos);

    // element access:
    constexpr bool operator[](size_t pos) const; // for b[i];
    reference operator[](size_t pos);            // for b[i];
    unsigned long to_ulong() const;
    unsigned long long to_ullong() const;
    template <class charT, class traits, class Allocator>
        basic_string<charT, traits, Allocator> to_string(charT zero = charT('0'), charT one = charT('1')) const;
    template <class charT, class traits>
        basic_string<charT, traits, allocator<charT> > to_string(charT zero = charT('0'), charT one = charT('1')) const;
    template <class charT>
        basic_string<charT, char_traits<charT>, allocator<charT> > to_string(charT zero = charT('0'), charT one = charT('1')) const;
    basic_string<char, char_traits<char>, allocator<char> > to_string(char zero = '0', char one = '1') const;
    size_t count() const noexcept;
    constexpr size_t size() const noexcept;
    bool operator==(const bitset& rhs) const noexcept;
    bool operator!=(const bitset& rhs) const noexcept;
    bool test(size_t pos) const;
    bool all() const noexcept;
    bool any() const noexcept;
    bool none() const noexcept;
    bitset operator<<(size_t pos) const noexcept;
    bitset operator>>(size_t pos) const noexcept;
};

// 23.3.5.3 bitset operators:
template <size_t N>
bitset<N> operator&(const bitset<N>&, const bitset<N>&) noexcept;

template <size_t N>
bitset<N> operator|(const bitset<N>&, const bitset<N>&) noexcept;

template <size_t N>
bitset<N> operator^(const bitset<N>&, const bitset<N>&) noexcept;

template <class charT, class traits, size_t N>
basic_istream<charT, traits>&
operator>>(basic_istream<charT, traits>& is, bitset<N>& x);

template <class charT, class traits, size_t N>
basic_ostream<charT, traits>&
operator<<(basic_ostream<charT, traits>& os, const bitset<N>& x);

template <size_t N> struct hash<std::bitset<N>>;

}  // std

*/

#include <__config>
#include <__bit_reference>
#include <__functional_base>
#include <climits>
#include <cstddef>
#include <iosfwd>
#include <stdexcept>
#include <string>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>


_LIBCPP_BEGIN_NAMESPACE_STD

template <size_t _N_words, size_t _Size>
class __bitset;

template <size_t _N_words, size_t _Size>
struct __has_storage_type<__bitset<_N_words, _Size> >
{
    static const bool value = true;
};

template <size_t _N_words, size_t _Size>
class __bitset
{
public:
    typedef ptrdiff_t              difference_type;
    typedef size_t                 size_type;
    typedef size_type              __storage_type;
protected:
    typedef __bitset __self;
    typedef       __storage_type*  __storage_pointer;
    typedef const __storage_type*  __const_storage_pointer;
    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);

    friend class __bit_reference<__bitset>;
    friend class __bit_const_reference<__bitset>;
    friend class __bit_iterator<__bitset, false>;
    friend class __bit_iterator<__bitset, true>;
    friend struct __bit_array<__bitset>;

    __storage_type __first_[_N_words];

    typedef __bit_reference<__bitset>                  reference;
    typedef __bit_const_reference<__bitset>            const_reference;
    typedef __bit_iterator<__bitset, false>            iterator;
    typedef __bit_iterator<__bitset, true>             const_iterator;

    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR __bitset() _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long __v) _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t __pos) _NOEXCEPT
        {return reference(__first_ + __pos / __bits_per_word, __storage_type(1) << __pos % __bits_per_word);}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t __pos) const _NOEXCEPT
        {return const_reference(__first_ + __pos / __bits_per_word, __storage_type(1) << __pos % __bits_per_word);}
    _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t __pos) _NOEXCEPT
        {return iterator(__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}
    _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t __pos) const _NOEXCEPT
        {return const_iterator(__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}

    _LIBCPP_INLINE_VISIBILITY
    void operator&=(const __bitset& __v) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    void operator|=(const __bitset& __v) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    void operator^=(const __bitset& __v) _NOEXCEPT;

    void flip() _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY unsigned long to_ulong() const
        {return to_ulong(integral_constant<bool, _Size < sizeof(unsigned long) * CHAR_BIT>());}
    _LIBCPP_INLINE_VISIBILITY unsigned long long to_ullong() const
        {return to_ullong(integral_constant<bool, _Size < sizeof(unsigned long long) * CHAR_BIT>());}

    bool all() const _NOEXCEPT;
    bool any() const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    size_t __hash_code() const _NOEXCEPT;
private:
#ifdef _LIBCPP_CXX03_LANG
    void __init(unsigned long long __v, false_type) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    void __init(unsigned long long __v, true_type) _NOEXCEPT;
#endif // _LIBCPP_CXX03_LANG
    unsigned long to_ulong(false_type) const;
    _LIBCPP_INLINE_VISIBILITY
    unsigned long to_ulong(true_type) const;
    unsigned long long to_ullong(false_type) const;
    _LIBCPP_INLINE_VISIBILITY
    unsigned long long to_ullong(true_type) const;
    _LIBCPP_INLINE_VISIBILITY
    unsigned long long to_ullong(true_type, false_type) const;
    unsigned long long to_ullong(true_type, true_type) const;
};

template <size_t _N_words, size_t _Size>
inline
_LIBCPP_CONSTEXPR
__bitset<_N_words, _Size>::__bitset() _NOEXCEPT
#ifndef _LIBCPP_CXX03_LANG
    : __first_{0}
#endif
{
#ifdef _LIBCPP_CXX03_LANG
    _VSTD::fill_n(__first_, _N_words, __storage_type(0));
#endif
}

#ifdef _LIBCPP_CXX03_LANG

template <size_t _N_words, size_t _Size>
void
__bitset<_N_words, _Size>::__init(unsigned long long __v, false_type) _NOEXCEPT
{
    __storage_type __t[sizeof(unsigned long long) / sizeof(__storage_type)];
    size_t __sz = _Size;
    for (size_t __i = 0; __i < sizeof(__t)/sizeof(__t[0]); ++__i, __v >>= __bits_per_word, __sz -= __bits_per_word )
        if ( __sz < __bits_per_word)
            __t[__i] = static_cast<__storage_type>(__v) & ( 1ULL << __sz ) - 1;
        else
            __t[__i] = static_cast<__storage_type>(__v);

    _VSTD::copy(__t, __t + sizeof(__t)/sizeof(__t[0]), __first_);
    _VSTD::fill(__first_ + sizeof(__t)/sizeof(__t[0]), __first_ + sizeof(__first_)/sizeof(__first_[0]),
               __storage_type(0));
}

template <size_t _N_words, size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
void
__bitset<_N_words, _Size>::__init(unsigned long long __v, true_type) _NOEXCEPT
{
    __first_[0] = __v;
    if (_Size < __bits_per_word)
        __first_[0] &= ( 1ULL << _Size ) - 1;

    _VSTD::fill(__first_ + 1, __first_ + sizeof(__first_)/sizeof(__first_[0]), __storage_type(0));
}

#endif // _LIBCPP_CXX03_LANG

template <size_t _N_words, size_t _Size>
inline
_LIBCPP_CONSTEXPR
__bitset<_N_words, _Size>::__bitset(unsigned long long __v) _NOEXCEPT
#ifndef _LIBCPP_CXX03_LANG
#if __SIZEOF_SIZE_T__ == 8
    : __first_{__v}
#elif __SIZEOF_SIZE_T__ == 4
    : __first_{static_cast<__storage_type>(__v),
                _Size >= 2 * __bits_per_word ? static_cast<__storage_type>(__v >> __bits_per_word)
                : static_cast<__storage_type>((__v >> __bits_per_word) & (__storage_type(1) << (_Size - __bits_per_word)) - 1)}
#else
#error This constructor has not been ported to this platform
#endif
#endif
{
#ifdef _LIBCPP_CXX03_LANG
    __init(__v, integral_constant<bool, sizeof(unsigned long long) == sizeof(__storage_type)>());
#endif
}

template <size_t _N_words, size_t _Size>
inline
void
__bitset<_N_words, _Size>::operator&=(const __bitset& __v) _NOEXCEPT
{
    for (size_type __i = 0; __i < _N_words; ++__i)
        __first_[__i] &= __v.__first_[__i];
}

template <size_t _N_words, size_t _Size>
inline
void
__bitset<_N_words, _Size>::operator|=(const __bitset& __v) _NOEXCEPT
{
    for (size_type __i = 0; __i < _N_words; ++__i)
        __first_[__i] |= __v.__first_[__i];
}

template <size_t _N_words, size_t _Size>
inline
void
__bitset<_N_words, _Size>::operator^=(const __bitset& __v) _NOEXCEPT
{
    for (size_type __i = 0; __i < _N_words; ++__i)
        __first_[__i] ^= __v.__first_[__i];
}

template <size_t _N_words, size_t _Size>
void
__bitset<_N_words, _Size>::flip() _NOEXCEPT
{
    // do middle whole words
    size_type __n = _Size;
    __storage_pointer __p = __first_;
    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
        *__p = ~*__p;
    // do last partial word
    if (__n > 0)
    {
        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
        __storage_type __b = *__p & __m;
        *__p &= ~__m;
        *__p |= ~__b & __m;
    }
}

template <size_t _N_words, size_t _Size>
unsigned long
__bitset<_N_words, _Size>::to_ulong(false_type) const
{
    const_iterator __e = __make_iter(_Size);
    const_iterator __i = _VSTD::find(__make_iter(sizeof(unsigned long) * CHAR_BIT), __e, true);
    if (__i != __e)
        __throw_overflow_error("bitset to_ulong overflow error");

    return __first_[0];
}

template <size_t _N_words, size_t _Size>
inline
unsigned long
__bitset<_N_words, _Size>::to_ulong(true_type) const
{
    return __first_[0];
}

template <size_t _N_words, size_t _Size>
unsigned long long
__bitset<_N_words, _Size>::to_ullong(false_type) const
{
    const_iterator __e = __make_iter(_Size);
    const_iterator __i = _VSTD::find(__make_iter(sizeof(unsigned long long) * CHAR_BIT), __e, true);
    if (__i != __e)
        __throw_overflow_error("bitset to_ullong overflow error");

    return to_ullong(true_type());
}

template <size_t _N_words, size_t _Size>
inline
unsigned long long
__bitset<_N_words, _Size>::to_ullong(true_type) const
{
    return to_ullong(true_type(), integral_constant<bool, sizeof(__storage_type) < sizeof(unsigned long long)>());
}

template <size_t _N_words, size_t _Size>
inline
unsigned long long
__bitset<_N_words, _Size>::to_ullong(true_type, false_type) const
{
    return __first_[0];
}

template <size_t _N_words, size_t _Size>
unsigned long long
__bitset<_N_words, _Size>::to_ullong(true_type, true_type) const
{
    unsigned long long __r = __first_[0];
    for (size_t __i = 1; __i < sizeof(unsigned long long) / sizeof(__storage_type); ++__i)
        __r |= static_cast<unsigned long long>(__first_[__i]) << (sizeof(__storage_type) * CHAR_BIT);
    return __r;
}

template <size_t _N_words, size_t _Size>
bool
__bitset<_N_words, _Size>::all() const _NOEXCEPT
{
    // do middle whole words
    size_type __n = _Size;
    __const_storage_pointer __p = __first_;
    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
        if (~*__p)
            return false;
    // do last partial word
    if (__n > 0)
    {
        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
        if (~*__p & __m)
            return false;
    }
    return true;
}

template <size_t _N_words, size_t _Size>
bool
__bitset<_N_words, _Size>::any() const _NOEXCEPT
{
    // do middle whole words
    size_type __n = _Size;
    __const_storage_pointer __p = __first_;
    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
        if (*__p)
            return true;
    // do last partial word
    if (__n > 0)
    {
        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
        if (*__p & __m)
            return true;
    }
    return false;
}

template <size_t _N_words, size_t _Size>
inline
size_t
__bitset<_N_words, _Size>::__hash_code() const _NOEXCEPT
{
    size_t __h = 0;
    for (size_type __i = 0; __i < _N_words; ++__i)
        __h ^= __first_[__i];
    return __h;
}

template <size_t _Size>
class __bitset<1, _Size>
{
public:
    typedef ptrdiff_t              difference_type;
    typedef size_t                 size_type;
    typedef size_type              __storage_type;
protected:
    typedef __bitset __self;
    typedef       __storage_type*  __storage_pointer;
    typedef const __storage_type*  __const_storage_pointer;
    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);

    friend class __bit_reference<__bitset>;
    friend class __bit_const_reference<__bitset>;
    friend class __bit_iterator<__bitset, false>;
    friend class __bit_iterator<__bitset, true>;
    friend struct __bit_array<__bitset>;

    __storage_type __first_;

    typedef __bit_reference<__bitset>                  reference;
    typedef __bit_const_reference<__bitset>            const_reference;
    typedef __bit_iterator<__bitset, false>            iterator;
    typedef __bit_iterator<__bitset, true>             const_iterator;

    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR __bitset() _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long __v) _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t __pos) _NOEXCEPT
        {return reference(&__first_, __storage_type(1) << __pos);}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t __pos) const _NOEXCEPT
        {return const_reference(&__first_, __storage_type(1) << __pos);}
    _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t __pos) _NOEXCEPT
        {return iterator(&__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}
    _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t __pos) const _NOEXCEPT
        {return const_iterator(&__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}

    _LIBCPP_INLINE_VISIBILITY
    void operator&=(const __bitset& __v) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    void operator|=(const __bitset& __v) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    void operator^=(const __bitset& __v) _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY
    void flip() _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY
    unsigned long to_ulong() const;
    _LIBCPP_INLINE_VISIBILITY
    unsigned long long to_ullong() const;

    _LIBCPP_INLINE_VISIBILITY
    bool all() const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bool any() const _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY
    size_t __hash_code() const _NOEXCEPT;
};

template <size_t _Size>
inline
_LIBCPP_CONSTEXPR
__bitset<1, _Size>::__bitset() _NOEXCEPT
    : __first_(0)
{
}

template <size_t _Size>
inline
_LIBCPP_CONSTEXPR
__bitset<1, _Size>::__bitset(unsigned long long __v) _NOEXCEPT
    : __first_(
        _Size == __bits_per_word ? static_cast<__storage_type>(__v)
                                 : static_cast<__storage_type>(__v) & ((__storage_type(1) << _Size) - 1)
    )
{
}

template <size_t _Size>
inline
void
__bitset<1, _Size>::operator&=(const __bitset& __v) _NOEXCEPT
{
    __first_ &= __v.__first_;
}

template <size_t _Size>
inline
void
__bitset<1, _Size>::operator|=(const __bitset& __v) _NOEXCEPT
{
    __first_ |= __v.__first_;
}

template <size_t _Size>
inline
void
__bitset<1, _Size>::operator^=(const __bitset& __v) _NOEXCEPT
{
    __first_ ^= __v.__first_;
}

template <size_t _Size>
inline
void
__bitset<1, _Size>::flip() _NOEXCEPT
{
    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - _Size);
    __first_ = ~__first_;
    __first_ &= __m;
}

template <size_t _Size>
inline
unsigned long
__bitset<1, _Size>::to_ulong() const
{
    return __first_;
}

template <size_t _Size>
inline
unsigned long long
__bitset<1, _Size>::to_ullong() const
{
    return __first_;
}

template <size_t _Size>
inline
bool
__bitset<1, _Size>::all() const _NOEXCEPT
{
    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - _Size);
    return !(~__first_ & __m);
}

template <size_t _Size>
inline
bool
__bitset<1, _Size>::any() const _NOEXCEPT
{
    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - _Size);
    return __first_ & __m;
}

template <size_t _Size>
inline
size_t
__bitset<1, _Size>::__hash_code() const _NOEXCEPT
{
    return __first_;
}

template <>
class __bitset<0, 0>
{
public:
    typedef ptrdiff_t              difference_type;
    typedef size_t                 size_type;
    typedef size_type              __storage_type;
protected:
    typedef __bitset __self;
    typedef       __storage_type*  __storage_pointer;
    typedef const __storage_type*  __const_storage_pointer;
    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);

    friend class __bit_reference<__bitset>;
    friend class __bit_const_reference<__bitset>;
    friend class __bit_iterator<__bitset, false>;
    friend class __bit_iterator<__bitset, true>;
    friend struct __bit_array<__bitset>;

    typedef __bit_reference<__bitset>                  reference;
    typedef __bit_const_reference<__bitset>            const_reference;
    typedef __bit_iterator<__bitset, false>            iterator;
    typedef __bit_iterator<__bitset, true>             const_iterator;

    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR __bitset() _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long) _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t) _NOEXCEPT
        {return reference(nullptr, 1);}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t) const _NOEXCEPT
        {return const_reference(nullptr, 1);}
    _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t) _NOEXCEPT
        {return iterator(nullptr, 0);}
    _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t) const _NOEXCEPT
        {return const_iterator(nullptr, 0);}

    _LIBCPP_INLINE_VISIBILITY void operator&=(const __bitset&) _NOEXCEPT {}
    _LIBCPP_INLINE_VISIBILITY void operator|=(const __bitset&) _NOEXCEPT {}
    _LIBCPP_INLINE_VISIBILITY void operator^=(const __bitset&) _NOEXCEPT {}

    _LIBCPP_INLINE_VISIBILITY void flip() _NOEXCEPT {}

    _LIBCPP_INLINE_VISIBILITY unsigned long to_ulong() const {return 0;}
    _LIBCPP_INLINE_VISIBILITY unsigned long long to_ullong() const {return 0;}

    _LIBCPP_INLINE_VISIBILITY bool all() const _NOEXCEPT {return true;}
    _LIBCPP_INLINE_VISIBILITY bool any() const _NOEXCEPT {return false;}

    _LIBCPP_INLINE_VISIBILITY size_t __hash_code() const _NOEXCEPT {return 0;}
};

inline
_LIBCPP_CONSTEXPR
__bitset<0, 0>::__bitset() _NOEXCEPT
{
}

inline
_LIBCPP_CONSTEXPR
__bitset<0, 0>::__bitset(unsigned long long) _NOEXCEPT
{
}

template <size_t _Size> class _LIBCPP_TEMPLATE_VIS bitset;
template <size_t _Size> struct hash<bitset<_Size> >;

template <size_t _Size>
class _LIBCPP_TEMPLATE_VIS bitset
    : private __bitset<_Size == 0 ? 0 : (_Size - 1) / (sizeof(size_t) * CHAR_BIT) + 1, _Size>
{
public:
    static const unsigned __n_words = _Size == 0 ? 0 : (_Size - 1) / (sizeof(size_t) * CHAR_BIT) + 1;
    typedef __bitset<__n_words, _Size> base;

public:
    typedef typename base::reference       reference;
    typedef typename base::const_reference const_reference;

    // 23.3.5.1 constructors:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR bitset() _NOEXCEPT {}
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
        bitset(unsigned long long __v) _NOEXCEPT : base(__v) {}
    template<class _CharT, class = __enable_if_t<_IsCharLikeType<_CharT>::value> >
        explicit bitset(const _CharT* __str,
                        typename basic_string<_CharT>::size_type __n = basic_string<_CharT>::npos,
                        _CharT __zero = _CharT('0'), _CharT __one = _CharT('1'));
    template<class _CharT, class _Traits, class _Allocator>
        explicit bitset(const basic_string<_CharT,_Traits,_Allocator>& __str,
                        typename basic_string<_CharT,_Traits,_Allocator>::size_type __pos = 0,
                        typename basic_string<_CharT,_Traits,_Allocator>::size_type __n =
                                (basic_string<_CharT,_Traits,_Allocator>::npos),
                        _CharT __zero = _CharT('0'), _CharT __one = _CharT('1'));

    // 23.3.5.2 bitset operations:
    _LIBCPP_INLINE_VISIBILITY
    bitset& operator&=(const bitset& __rhs) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bitset& operator|=(const bitset& __rhs) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bitset& operator^=(const bitset& __rhs) _NOEXCEPT;
    bitset& operator<<=(size_t __pos) _NOEXCEPT;
    bitset& operator>>=(size_t __pos) _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bitset& set() _NOEXCEPT;
    bitset& set(size_t __pos, bool __val = true);
    _LIBCPP_INLINE_VISIBILITY
    bitset& reset() _NOEXCEPT;
    bitset& reset(size_t __pos);
    _LIBCPP_INLINE_VISIBILITY
    bitset  operator~() const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bitset& flip() _NOEXCEPT;
    bitset& flip(size_t __pos);

    // element access:
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
                              const_reference operator[](size_t __p) const {return base::__make_ref(__p);}
    _LIBCPP_INLINE_VISIBILITY       reference operator[](size_t __p)       {return base::__make_ref(__p);}
    _LIBCPP_INLINE_VISIBILITY
    unsigned long to_ulong() const;
    _LIBCPP_INLINE_VISIBILITY
    unsigned long long to_ullong() const;
    template <class _CharT, class _Traits, class _Allocator>
        basic_string<_CharT, _Traits, _Allocator> to_string(_CharT __zero = _CharT('0'),
                                                            _CharT __one = _CharT('1')) const;
    template <class _CharT, class _Traits>
        _LIBCPP_INLINE_VISIBILITY
        basic_string<_CharT, _Traits, allocator<_CharT> > to_string(_CharT __zero = _CharT('0'),
                                                                    _CharT __one = _CharT('1')) const;
    template <class _CharT>
        _LIBCPP_INLINE_VISIBILITY
        basic_string<_CharT, char_traits<_CharT>, allocator<_CharT> > to_string(_CharT __zero = _CharT('0'),
                                                                                _CharT __one = _CharT('1')) const;
    _LIBCPP_INLINE_VISIBILITY
    basic_string<char, char_traits<char>, allocator<char> > to_string(char __zero = '0',
                                                                      char __one = '1') const;
    _LIBCPP_INLINE_VISIBILITY
    size_t count() const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR size_t size() const _NOEXCEPT {return _Size;}
    _LIBCPP_INLINE_VISIBILITY
    bool operator==(const bitset& __rhs) const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bool operator!=(const bitset& __rhs) const _NOEXCEPT;
    bool test(size_t __pos) const;
    _LIBCPP_INLINE_VISIBILITY
    bool all() const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bool any() const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY bool none() const _NOEXCEPT {return !any();}
    _LIBCPP_INLINE_VISIBILITY
    bitset operator<<(size_t __pos) const _NOEXCEPT;
    _LIBCPP_INLINE_VISIBILITY
    bitset operator>>(size_t __pos) const _NOEXCEPT;

private:

    _LIBCPP_INLINE_VISIBILITY
    size_t __hash_code() const _NOEXCEPT {return base::__hash_code();}

    friend struct hash<bitset>;
};

template <size_t _Size>
template<class _CharT, class>
bitset<_Size>::bitset(const _CharT* __str,
                      typename basic_string<_CharT>::size_type __n,
                      _CharT __zero, _CharT __one)
{
    size_t __rlen = _VSTD::min(__n, char_traits<_CharT>::length(__str));
    for (size_t __i = 0; __i < __rlen; ++__i)
        if (__str[__i] != __zero && __str[__i] != __one)
            __throw_invalid_argument("bitset string ctor has invalid argument");

    size_t _Mp = _VSTD::min(__rlen, _Size);
    size_t __i = 0;
    for (; __i < _Mp; ++__i)
    {
        _CharT __c = __str[_Mp - 1 - __i];
        (*this)[__i] = (__c == __one);
    }
    _VSTD::fill(base::__make_iter(__i), base::__make_iter(_Size), false);
}

template <size_t _Size>
template<class _CharT, class _Traits, class _Allocator>
bitset<_Size>::bitset(const basic_string<_CharT,_Traits,_Allocator>& __str,
       typename basic_string<_CharT,_Traits,_Allocator>::size_type __pos,
       typename basic_string<_CharT,_Traits,_Allocator>::size_type __n,
       _CharT __zero, _CharT __one)
{
    if (__pos > __str.size())
        __throw_out_of_range("bitset string pos out of range");

    size_t __rlen = _VSTD::min(__n, __str.size() - __pos);
    for (size_t __i = __pos; __i < __pos + __rlen; ++__i)
        if (!_Traits::eq(__str[__i], __zero) && !_Traits::eq(__str[__i], __one))
            __throw_invalid_argument("bitset string ctor has invalid argument");

    size_t _Mp = _VSTD::min(__rlen, _Size);
    size_t __i = 0;
    for (; __i < _Mp; ++__i)
    {
        _CharT __c = __str[__pos + _Mp - 1 - __i];
        (*this)[__i] = _Traits::eq(__c, __one);
    }
    _VSTD::fill(base::__make_iter(__i), base::__make_iter(_Size), false);
}

template <size_t _Size>
inline
bitset<_Size>&
bitset<_Size>::operator&=(const bitset& __rhs) _NOEXCEPT
{
    base::operator&=(__rhs);
    return *this;
}

template <size_t _Size>
inline
bitset<_Size>&
bitset<_Size>::operator|=(const bitset& __rhs) _NOEXCEPT
{
    base::operator|=(__rhs);
    return *this;
}

template <size_t _Size>
inline
bitset<_Size>&
bitset<_Size>::operator^=(const bitset& __rhs) _NOEXCEPT
{
    base::operator^=(__rhs);
    return *this;
}

template <size_t _Size>
bitset<_Size>&
bitset<_Size>::operator<<=(size_t __pos) _NOEXCEPT
{
    __pos = _VSTD::min(__pos, _Size);
    _VSTD::copy_backward(base::__make_iter(0), base::__make_iter(_Size - __pos), base::__make_iter(_Size));
    _VSTD::fill_n(base::__make_iter(0), __pos, false);
    return *this;
}

template <size_t _Size>
bitset<_Size>&
bitset<_Size>::operator>>=(size_t __pos) _NOEXCEPT
{
    __pos = _VSTD::min(__pos, _Size);
    _VSTD::copy(base::__make_iter(__pos), base::__make_iter(_Size), base::__make_iter(0));
    _VSTD::fill_n(base::__make_iter(_Size - __pos), __pos, false);
    return *this;
}

template <size_t _Size>
inline
bitset<_Size>&
bitset<_Size>::set() _NOEXCEPT
{
    _VSTD::fill_n(base::__make_iter(0), _Size, true);
    return *this;
}

template <size_t _Size>
bitset<_Size>&
bitset<_Size>::set(size_t __pos, bool __val)
{
    if (__pos >= _Size)
        __throw_out_of_range("bitset set argument out of range");

    (*this)[__pos] = __val;
    return *this;
}

template <size_t _Size>
inline
bitset<_Size>&
bitset<_Size>::reset() _NOEXCEPT
{
    _VSTD::fill_n(base::__make_iter(0), _Size, false);
    return *this;
}

template <size_t _Size>
bitset<_Size>&
bitset<_Size>::reset(size_t __pos)
{
    if (__pos >= _Size)
        __throw_out_of_range("bitset reset argument out of range");

    (*this)[__pos] = false;
    return *this;
}

template <size_t _Size>
inline
bitset<_Size>
bitset<_Size>::operator~() const _NOEXCEPT
{
    bitset __x(*this);
    __x.flip();
    return __x;
}

template <size_t _Size>
inline
bitset<_Size>&
bitset<_Size>::flip() _NOEXCEPT
{
    base::flip();
    return *this;
}

template <size_t _Size>
bitset<_Size>&
bitset<_Size>::flip(size_t __pos)
{
    if (__pos >= _Size)
        __throw_out_of_range("bitset flip argument out of range");

    reference r = base::__make_ref(__pos);
    r = ~r;
    return *this;
}

template <size_t _Size>
inline
unsigned long
bitset<_Size>::to_ulong() const
{
    return base::to_ulong();
}

template <size_t _Size>
inline
unsigned long long
bitset<_Size>::to_ullong() const
{
    return base::to_ullong();
}

template <size_t _Size>
template <class _CharT, class _Traits, class _Allocator>
basic_string<_CharT, _Traits, _Allocator>
bitset<_Size>::to_string(_CharT __zero, _CharT __one) const
{
    basic_string<_CharT, _Traits, _Allocator> __r(_Size, __zero);
    for (size_t __i = 0; __i < _Size; ++__i)
    {
        if ((*this)[__i])
            __r[_Size - 1 - __i] = __one;
    }
    return __r;
}

template <size_t _Size>
template <class _CharT, class _Traits>
inline
basic_string<_CharT, _Traits, allocator<_CharT> >
bitset<_Size>::to_string(_CharT __zero, _CharT __one) const
{
    return to_string<_CharT, _Traits, allocator<_CharT> >(__zero, __one);
}

template <size_t _Size>
template <class _CharT>
inline
basic_string<_CharT, char_traits<_CharT>, allocator<_CharT> >
bitset<_Size>::to_string(_CharT __zero, _CharT __one) const
{
    return to_string<_CharT, char_traits<_CharT>, allocator<_CharT> >(__zero, __one);
}

template <size_t _Size>
inline
basic_string<char, char_traits<char>, allocator<char> >
bitset<_Size>::to_string(char __zero, char __one) const
{
    return to_string<char, char_traits<char>, allocator<char> >(__zero, __one);
}

template <size_t _Size>
inline
size_t
bitset<_Size>::count() const _NOEXCEPT
{
    return static_cast<size_t>(_VSTD::__count_bool_true(base::__make_iter(0), _Size));
}

template <size_t _Size>
inline
bool
bitset<_Size>::operator==(const bitset& __rhs) const _NOEXCEPT
{
    return _VSTD::equal(base::__make_iter(0), base::__make_iter(_Size), __rhs.__make_iter(0));
}

template <size_t _Size>
inline
bool
bitset<_Size>::operator!=(const bitset& __rhs) const _NOEXCEPT
{
    return !(*this == __rhs);
}

template <size_t _Size>
bool
bitset<_Size>::test(size_t __pos) const
{
    if (__pos >= _Size)
        __throw_out_of_range("bitset test argument out of range");

    return (*this)[__pos];
}

template <size_t _Size>
inline
bool
bitset<_Size>::all() const _NOEXCEPT
{
    return base::all();
}

template <size_t _Size>
inline
bool
bitset<_Size>::any() const _NOEXCEPT
{
    return base::any();
}

template <size_t _Size>
inline
bitset<_Size>
bitset<_Size>::operator<<(size_t __pos) const _NOEXCEPT
{
    bitset __r = *this;
    __r <<= __pos;
    return __r;
}

template <size_t _Size>
inline
bitset<_Size>
bitset<_Size>::operator>>(size_t __pos) const _NOEXCEPT
{
    bitset __r = *this;
    __r >>= __pos;
    return __r;
}

template <size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
bitset<_Size>
operator&(const bitset<_Size>& __x, const bitset<_Size>& __y) _NOEXCEPT
{
    bitset<_Size> __r = __x;
    __r &= __y;
    return __r;
}

template <size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
bitset<_Size>
operator|(const bitset<_Size>& __x, const bitset<_Size>& __y) _NOEXCEPT
{
    bitset<_Size> __r = __x;
    __r |= __y;
    return __r;
}

template <size_t _Size>
inline _LIBCPP_INLINE_VISIBILITY
bitset<_Size>
operator^(const bitset<_Size>& __x, const bitset<_Size>& __y) _NOEXCEPT
{
    bitset<_Size> __r = __x;
    __r ^= __y;
    return __r;
}

template <size_t _Size>
struct _LIBCPP_TEMPLATE_VIS hash<bitset<_Size> >
    : public unary_function<bitset<_Size>, size_t>
{
    _LIBCPP_INLINE_VISIBILITY
    size_t operator()(const bitset<_Size>& __bs) const _NOEXCEPT
        {return __bs.__hash_code();}
};

template <class _CharT, class _Traits, size_t _Size>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, bitset<_Size>& __x);

template <class _CharT, class _Traits, size_t _Size>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os, const bitset<_Size>& __x);

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP_BITSET