[thirdparty/gcc.git] / libstdc++-v3 / include / std / std_bitset.h

// <bitset> -*- C++ -*-

// Copyright (C) 2001, 2002 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 2, 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.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 * Copyright (c) 1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */ 

/** @file bitset
 *  This is a Standard C++ Library header.  You should @c #include this header
 *  in your programs, rather than any of the "st[dl]_*.h" implementation files.
 */

#ifndef __GLIBCPP_BITSET
#define __GLIBCPP_BITSET

#pragma GCC system_header

// A bitset of size N has N % (sizeof(unsigned long) * CHAR_BIT) unused 
// bits.  (They are the high- order bits in the highest word.)  It is
// a class invariant of class bitset<> that those unused bits are
// always zero.

// Most of the actual code isn't contained in bitset<> itself, but in the 
// base class _Base_bitset.  The base class works with whole words, not with
// individual bits.  This allows us to specialize _Base_bitset for the
// important special case where the bitset is only a single word.

#include <cstddef>     // for size_t
#include <cstring>     // for memset
#include <string>
#include <bits/functexcept.h>   // for invalid_argument, out_of_range, 
			         // overflow_error
#include <ostream>     // for ostream (operator<<)
#include <istream>     // for istream (operator>>)

#define _GLIBCPP_BITSET_BITS_PER_WORD (CHAR_BIT*sizeof(unsigned long))
#define __BITSET_WORDS(__n) \
 ((__n) < 1 ? 1 : ((__n) + _GLIBCPP_BITSET_BITS_PER_WORD - 1)/_GLIBCPP_BITSET_BITS_PER_WORD)

namespace std
{
  extern unsigned char 	_S_bit_count[256];
  extern unsigned char 	_S_first_one[256];

  // Base class: general case.
  template<size_t _Nw>
    struct _Base_bitset 
    {
      typedef unsigned long _WordT;

      // 0 is the least significant word.
      _WordT 		_M_w[_Nw];                
      
      _Base_bitset() { _M_do_reset(); }
      _Base_bitset(unsigned long __val) 
      {
	_M_do_reset();
	_M_w[0] = __val;
      }

      static size_t 
      _S_whichword(size_t __pos )
      { return __pos / _GLIBCPP_BITSET_BITS_PER_WORD; }

      static size_t 
      _S_whichbyte(size_t __pos )
      { return (__pos % _GLIBCPP_BITSET_BITS_PER_WORD) / CHAR_BIT; }

      static size_t 
      _S_whichbit(size_t __pos )
      { return __pos % _GLIBCPP_BITSET_BITS_PER_WORD; }

      static _WordT 
      _S_maskbit(size_t __pos )
      { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }

      _WordT& 
      _M_getword(size_t __pos)       
      { return _M_w[_S_whichword(__pos)]; }

      _WordT  
      _M_getword(size_t __pos) const 
      { return _M_w[_S_whichword(__pos)]; }

      _WordT& 
      _M_hiword() { return _M_w[_Nw - 1]; }

      _WordT  
      _M_hiword() const { return _M_w[_Nw - 1]; }

      void 
      _M_do_and(const _Base_bitset<_Nw>& __x) 
      {
	for (size_t __i = 0; __i < _Nw; __i++) 
	  _M_w[__i] &= __x._M_w[__i];
      }

      void 
      _M_do_or(const _Base_bitset<_Nw>& __x) 
      {
	for (size_t __i = 0; __i < _Nw; __i++) 
	  _M_w[__i] |= __x._M_w[__i];
      }

      void 
      _M_do_xor(const _Base_bitset<_Nw>& __x) 
      {
	for (size_t __i = 0; __i < _Nw; __i++)
	  _M_w[__i] ^= __x._M_w[__i];
      }

      void 
      _M_do_left_shift(size_t __shift);

      void 
      _M_do_right_shift(size_t __shift);
      
      void 
      _M_do_flip() 
      {
	for (size_t __i = 0; __i < _Nw; __i++) 
	  _M_w[__i] = ~_M_w[__i];
      }

      void 
      _M_do_set() 
      {
	for (size_t __i = 0; __i < _Nw; __i++)
	  _M_w[__i] = ~static_cast<_WordT>(0);
      }

      void 
      _M_do_reset() { memset(_M_w, 0, _Nw * sizeof(_WordT)); }

      bool 
      _M_is_equal(const _Base_bitset<_Nw>& __x) const 
      {
	for (size_t __i = 0; __i < _Nw; ++__i) 
	  {
	    if (_M_w[__i] != __x._M_w[__i])
	      return false;
	  }
	return true;
      }

      bool 
      _M_is_any() const 
      {
	for (size_t __i = 0; __i < _Nw; __i++) 
	  {
	    if (_M_w[__i] != static_cast<_WordT>(0))
	      return true;
	  }
	return false;
      }

      size_t 
      _M_do_count() const 
      {
	size_t __result = 0;
	const unsigned char* __byte_ptr = (const unsigned char*)_M_w;
	const unsigned char* __end_ptr = (const unsigned char*)(_M_w + _Nw);
	
	while ( __byte_ptr < __end_ptr ) 
	  {
	    __result += _S_bit_count[*__byte_ptr];
	    __byte_ptr++;
	  }
	return __result;
      }

      unsigned long 
      _M_do_to_ulong() const; 

      // find first "on" bit
      size_t 
      _M_do_find_first(size_t __not_found) const;

      // find the next "on" bit that follows "prev"
      size_t 
      _M_do_find_next(size_t __prev, size_t __not_found) const;
    };

  // Definitions of non-inline functions from _Base_bitset.
  template<size_t _Nw>
    void 
    _Base_bitset<_Nw>::_M_do_left_shift(size_t __shift) 
    {
      if (__shift != 0) 
	{
	  const size_t __wshift = __shift / _GLIBCPP_BITSET_BITS_PER_WORD;
	  const size_t __offset = __shift % _GLIBCPP_BITSET_BITS_PER_WORD;
	  
	  if (__offset == 0)
	    for (size_t __n = _Nw - 1; __n >= __wshift; --__n)
	      _M_w[__n] = _M_w[__n - __wshift];
	  else 
	    {
	      const size_t __sub_offset = _GLIBCPP_BITSET_BITS_PER_WORD - __offset;
	      for (size_t __n = _Nw - 1; __n > __wshift; --__n)
		_M_w[__n] = (_M_w[__n - __wshift] << __offset) | 
		  (_M_w[__n - __wshift - 1] >> __sub_offset);
	      _M_w[__wshift] = _M_w[0] << __offset;
	    }
	  
	  fill(_M_w + 0, _M_w + __wshift, static_cast<_WordT>(0));
	}
    }
  
  template<size_t _Nw>
    void 
    _Base_bitset<_Nw>::_M_do_right_shift(size_t __shift) 
    {
      if (__shift != 0) 
	{
	  const size_t __wshift = __shift / _GLIBCPP_BITSET_BITS_PER_WORD;
	  const size_t __offset = __shift % _GLIBCPP_BITSET_BITS_PER_WORD;
	  const size_t __limit = _Nw - __wshift - 1;
	  
	  if (__offset == 0)
	    for (size_t __n = 0; __n <= __limit; ++__n)
	      _M_w[__n] = _M_w[__n + __wshift];
	  else 
	    {
	      const size_t __sub_offset = _GLIBCPP_BITSET_BITS_PER_WORD - __offset;
	      for (size_t __n = 0; __n < __limit; ++__n)
		_M_w[__n] = (_M_w[__n + __wshift] >> __offset) |
		  (_M_w[__n + __wshift + 1] << __sub_offset);
	      _M_w[__limit] = _M_w[_Nw-1] >> __offset;
	    }
	  
	  fill(_M_w + __limit + 1, _M_w + _Nw, static_cast<_WordT>(0));
	}
    }

  template<size_t _Nw>
    unsigned long 
    _Base_bitset<_Nw>::_M_do_to_ulong() const
    {
      for (size_t __i = 1; __i < _Nw; ++__i) 
	if (_M_w[__i]) 
	  __throw_overflow_error("bitset");
      return _M_w[0];
    }

  template<size_t _Nw>
    size_t 
    _Base_bitset<_Nw>::_M_do_find_first(size_t __not_found) const 
    {
      for (size_t __i = 0; __i < _Nw; __i++ ) 
	{
	  _WordT __thisword = _M_w[__i];
	  if ( __thisword != static_cast<_WordT>(0) ) 
	    {
	      // find byte within word
	      for (size_t __j = 0; __j < sizeof(_WordT); __j++ ) 
		{
		  unsigned char __this_byte
		    = static_cast<unsigned char>(__thisword & (~(unsigned char)0));
		  if (__this_byte)
		    return __i*_GLIBCPP_BITSET_BITS_PER_WORD + __j*CHAR_BIT +
		      _S_first_one[__this_byte];

		  __thisword >>= CHAR_BIT;
		}
	    }
	}
      // not found, so return an indication of failure.
      return __not_found;
    }

  template<size_t _Nw>
    size_t
    _Base_bitset<_Nw>::_M_do_find_next(size_t __prev, size_t __not_found) const
    { 
      // make bound inclusive
      ++__prev;
      
      // check out of bounds
      if ( __prev >= _Nw * _GLIBCPP_BITSET_BITS_PER_WORD )
	return __not_found;
      
      // search first word
      size_t __i = _S_whichword(__prev);
      _WordT __thisword = _M_w[__i];
      
      // mask off bits below bound
      __thisword &= (~static_cast<_WordT>(0)) << _S_whichbit(__prev);
      
      if ( __thisword != static_cast<_WordT>(0) ) 
	{
	  // find byte within word
	  // get first byte into place
	  __thisword >>= _S_whichbyte(__prev) * CHAR_BIT;
	  for (size_t __j = _S_whichbyte(__prev); __j < sizeof(_WordT); __j++)
	    {
	      unsigned char __this_byte
		= static_cast<unsigned char>(__thisword & (~(unsigned char)0));
	      if ( __this_byte )
		return __i*_GLIBCPP_BITSET_BITS_PER_WORD + __j*CHAR_BIT +
		  _S_first_one[__this_byte];
	      
	      __thisword >>= CHAR_BIT;
	    }
	}
      
      // check subsequent words
      __i++;
      for ( ; __i < _Nw; __i++ ) 
	{
	  __thisword = _M_w[__i];
	  if ( __thisword != static_cast<_WordT>(0) ) 
	    {
	      // find byte within word
	      for (size_t __j = 0; __j < sizeof(_WordT); __j++ ) 
		{
		  unsigned char __this_byte
		    = static_cast<unsigned char>(__thisword & (~(unsigned char)0));
		  if ( __this_byte )
		    return __i*_GLIBCPP_BITSET_BITS_PER_WORD + __j*CHAR_BIT +
		      _S_first_one[__this_byte];
		  
		  __thisword >>= CHAR_BIT;
		}
	    }
	}
      // not found, so return an indication of failure.
      return __not_found;
    } // end _M_do_find_next
  

  // Base class: specialization for a single word.
  template<> 
    struct _Base_bitset<1> 
    {
      typedef unsigned long _WordT;
      _WordT _M_w;

      _Base_bitset( void ) : _M_w(0) {}
      _Base_bitset(unsigned long __val) : _M_w(__val) {}

      static size_t 
      _S_whichword(size_t __pos )
      { return __pos / _GLIBCPP_BITSET_BITS_PER_WORD; }

      static size_t 
      _S_whichbyte(size_t __pos )
      { return (__pos % _GLIBCPP_BITSET_BITS_PER_WORD) / CHAR_BIT; }

      static size_t 
      _S_whichbit(size_t __pos )
      {  return __pos % _GLIBCPP_BITSET_BITS_PER_WORD; }

      static _WordT 
      _S_maskbit(size_t __pos )
      { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }

      _WordT& 
      _M_getword(size_t) { return _M_w; }

      _WordT  
      _M_getword(size_t) const { return _M_w; }

      _WordT& 
      _M_hiword() { return _M_w; }

      _WordT  
      _M_hiword() const { return _M_w; }

      void 
      _M_do_and(const _Base_bitset<1>& __x) { _M_w &= __x._M_w; }

      void 
      _M_do_or(const _Base_bitset<1>& __x)  { _M_w |= __x._M_w; }

      void 
      _M_do_xor(const _Base_bitset<1>& __x) { _M_w ^= __x._M_w; }

      void 
      _M_do_left_shift(size_t __shift) { _M_w <<= __shift; }

      void 
      _M_do_right_shift(size_t __shift) { _M_w >>= __shift; }

      void 
      _M_do_flip() { _M_w = ~_M_w; }

      void 
      _M_do_set() { _M_w = ~static_cast<_WordT>(0); }

      void 
      _M_do_reset() { _M_w = 0; }

      bool 
      _M_is_equal(const _Base_bitset<1>& __x) const
      { return _M_w == __x._M_w; }

      bool 
      _M_is_any() const { return _M_w != 0; }

      size_t 
      _M_do_count() const 
      {
	size_t __result = 0;
	const unsigned char* __byte_ptr = (const unsigned char*)&_M_w;
	const unsigned char* __end_ptr
	  = ((const unsigned char*)&_M_w)+sizeof(_M_w);
	while ( __byte_ptr < __end_ptr ) 
	  {
	    __result += _S_bit_count[*__byte_ptr];
	    __byte_ptr++;
	  }
	return __result;
      }

      unsigned long 
      _M_do_to_ulong() const { return _M_w; }

      size_t 
      _M_do_find_first(size_t __not_found) const;

      // find the next "on" bit that follows "prev"
      size_t
      _M_do_find_next(size_t __prev, size_t __not_found) const; 
    };

  // Helper class to zero out the unused high-order bits in the highest word.
  template<size_t _Extrabits> 
    struct _Sanitize 
    {
      static void _S_do_sanitize(unsigned long& __val)
      { __val &= ~((~static_cast<unsigned long>(0)) << _Extrabits); }
    };

  template<> 
    struct _Sanitize<0> 
    { static void _S_do_sanitize(unsigned long) { } };

  // Class bitset.
  // _Nb may be any nonzero number of type size_t.
  template<size_t _Nb>
    class bitset : private _Base_bitset<__BITSET_WORDS(_Nb)>
  {
  private:
    typedef _Base_bitset<__BITSET_WORDS(_Nb)> _Base;
    typedef unsigned long _WordT;
    
    void 
    _M_do_sanitize() 
    {
    _Sanitize<_Nb%_GLIBCPP_BITSET_BITS_PER_WORD>::_S_do_sanitize(this->_M_hiword());
    }

  public:
    // bit reference:
    class reference;
    friend class reference;
    
    class reference 
    {
      friend class bitset;
      
      _WordT *_M_wp;
      size_t _M_bpos;
      
      // left undefined
      reference();
      
    public:
      reference( bitset& __b, size_t __pos ) 
      {
	_M_wp = &__b._M_getword(__pos);
	_M_bpos = _Base::_S_whichbit(__pos);
      }

      ~reference() { }

      // for b[i] = __x;
      reference& 
      operator=(bool __x) 
      {
	if ( __x )
	  *_M_wp |= _Base::_S_maskbit(_M_bpos);
	else
	  *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
	return *this;
      }
      
      // for b[i] = b[__j];
      reference& 
      operator=(const reference& __j) 
      {
	if ( (*(__j._M_wp) & _Base::_S_maskbit(__j._M_bpos)) )
	  *_M_wp |= _Base::_S_maskbit(_M_bpos);
	else
	  *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
	return *this;
      }

      // flips the bit
      bool 
      operator~() const
      { return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) == 0; }

      // for __x = b[i];
      operator bool() const
      { return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) != 0; }

      // for b[i].flip();
      reference& 
      flip() 
      {
	*_M_wp ^= _Base::_S_maskbit(_M_bpos);
	return *this;
      }
    };
    
    // 23.3.5.1 constructors:
    bitset() { }

    bitset(unsigned long __val) : _Base_bitset<__BITSET_WORDS(_Nb)>(__val) 
    { _M_do_sanitize(); }

    template<class _CharT, class _Traits, class _Alloc>
      explicit bitset(const basic_string<_CharT, _Traits, _Alloc>& __s,
		      size_t __pos = 0) : _Base() 
      {
	if (__pos > __s.size()) 
	  __throw_out_of_range("bitset");
	_M_copy_from_string(__s, __pos,
			    basic_string<_CharT, _Traits, _Alloc>::npos);
      }

    template<class _CharT, class _Traits, class _Alloc>
      bitset(const basic_string<_CharT, _Traits, _Alloc>& __s,
	     size_t __pos, size_t __n) : _Base() 
      {
	if (__pos > __s.size()) 
	  __throw_out_of_range("bitset");
	_M_copy_from_string(__s, __pos, __n);
      }

    // 23.3.5.2 bitset operations:
    bitset<_Nb>& 
    operator&=(const bitset<_Nb>& __rhs) 
    {
      this->_M_do_and(__rhs);
      return *this;
    }

    bitset<_Nb>& 
    operator|=(const bitset<_Nb>& __rhs) 
    {
      this->_M_do_or(__rhs);
      return *this;
    }

    bitset<_Nb>& 
    operator^=(const bitset<_Nb>& __rhs) 
    {
      this->_M_do_xor(__rhs);
      return *this;
    }

    bitset<_Nb>& 
    operator<<=(size_t __pos) 
    {
      this->_M_do_left_shift(__pos);
      this->_M_do_sanitize();
      return *this;
    }

    bitset<_Nb>& 
    operator>>=(size_t __pos) 
    {
      this->_M_do_right_shift(__pos);
      this->_M_do_sanitize();
      return *this;
    }

    // Extension:
    // Versions of single-bit set, reset, flip, test with no range checking.
    bitset<_Nb>& 
    _Unchecked_set(size_t __pos) 
    {
      this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
      return *this;
    }

    bitset<_Nb>& 
    _Unchecked_set(size_t __pos, int __val) 
    {
      if (__val)
	this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
      else
	this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
      return *this;
    }

    bitset<_Nb>& 
    _Unchecked_reset(size_t __pos) 
    {
      this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
      return *this;
    }

    bitset<_Nb>& 
    _Unchecked_flip(size_t __pos) 
    {
      this->_M_getword(__pos) ^= _Base::_S_maskbit(__pos);
      return *this;
    }

    bool 
    _Unchecked_test(size_t __pos) const 
    {
      return (this->_M_getword(__pos) & _Base::_S_maskbit(__pos)) 
	!= static_cast<_WordT>(0);
    }

    // Set, reset, and flip.
    bitset<_Nb>& 
    set() 
    {
      this->_M_do_set();
      this->_M_do_sanitize();
      return *this;
    }

    bitset<_Nb>& 
    set(size_t __pos, bool __val = true) 
    {
      if (__pos >= _Nb)
	__throw_out_of_range("bitset");
      return _Unchecked_set(__pos, __val);
    }

    bitset<_Nb>& 
    reset() 
    {
      this->_M_do_reset();
      return *this;
    }

    bitset<_Nb>& 
    reset(size_t __pos) 
    {
      if (__pos >= _Nb)
	__throw_out_of_range("bitset");
      return _Unchecked_reset(__pos);
    }

    bitset<_Nb>& 
    flip() 
    {
      this->_M_do_flip();
      this->_M_do_sanitize();
      return *this;
    }

    bitset<_Nb>& 
    flip(size_t __pos) 
    {
      if (__pos >= _Nb)
	__throw_out_of_range("bitset");
      return _Unchecked_flip(__pos);
    }

    bitset<_Nb> 
    operator~() const { return bitset<_Nb>(*this).flip(); }

    // element access:
    //for b[i];
    // _GLIBCPP_RESOLVE_LIB_DEFECTS Note that this implementation already
    // resolves DR 11 (items 1 and 2), but does not do the range-checking
    // required by that DR's resolution.  -pme
    reference 
    operator[](size_t __pos) { return reference(*this,__pos); }

    bool 
    operator[](size_t __pos) const { return _Unchecked_test(__pos); }

    unsigned long 
    to_ulong() const { return this->_M_do_to_ulong(); }

    template<class _CharT, class _Traits, class _Alloc>
      basic_string<_CharT, _Traits, _Alloc> 
      to_string() const 
      {
	basic_string<_CharT, _Traits, _Alloc> __result;
	_M_copy_to_string(__result);
	return __result;
      }

    // Helper functions for string operations.
    template<class _CharT, class _Traits, class _Alloc>
      void 
      _M_copy_from_string(const basic_string<_CharT,_Traits,_Alloc>& __s,
                          size_t, size_t);

    template<class _CharT, class _Traits, class _Alloc>
      void 
      _M_copy_to_string(basic_string<_CharT,_Traits,_Alloc>&) const;

    size_t 
    count() const { return this->_M_do_count(); }

    size_t 
    size() const { return _Nb; }

    bool 
    operator==(const bitset<_Nb>& __rhs) const 
    { return this->_M_is_equal(__rhs); }

    bool 
    operator!=(const bitset<_Nb>& __rhs) const 
    { return !this->_M_is_equal(__rhs); }

    bool 
    test(size_t __pos) const 
    {
      if (__pos >= _Nb)
	__throw_out_of_range("bitset");
      return _Unchecked_test(__pos);
    }

    bool 
    any() const { return this->_M_is_any(); }

    bool 
    none() const { return !this->_M_is_any(); }

    bitset<_Nb> 
    operator<<(size_t __pos) const
    { return bitset<_Nb>(*this) <<= __pos; }

    bitset<_Nb> 
    operator>>(size_t __pos) const
    { return bitset<_Nb>(*this) >>= __pos; }

    // EXTENSIONS: bit-find operations.  These operations are
    // experimental, and are subject to change or removal in future
    // versions.

    // find the index of the first "on" bit
    size_t 
    _Find_first() const 
    { return this->_M_do_find_first(_Nb); }

    // find the index of the next "on" bit after prev
    size_t 
    _Find_next(size_t __prev ) const 
    { return this->_M_do_find_next(__prev, _Nb); }
  };

  // Definitions of non-inline member functions.
  template<size_t _Nb>
    template<class _CharT, class _Traits, class _Alloc>
    void 
    bitset<_Nb>::_M_copy_from_string(const basic_string<_CharT,_Traits,_Alloc>& __s, size_t __pos, size_t __n)
    {  
      reset();
      const size_t __nbits = min(_Nb, min(__n, __s.size() - __pos));
      for (size_t __i = 0; __i < __nbits; ++__i) 
	{
	  switch(__s[__pos + __nbits - __i - 1]) 
	    {
	    case '0':
	      break;
	    case '1':
	      set(__i);
	      break;
	    default:
	      __throw_invalid_argument("bitset");
	    }
	}
    }

  template<size_t _Nb>
    template<class _CharT, class _Traits, class _Alloc>
    void 
    bitset<_Nb>::_M_copy_to_string(basic_string<_CharT, _Traits, _Alloc>& __s) const
    {
      __s.assign(_Nb, '0');
      for (size_t __i = 0; __i < _Nb; ++__i) 
	if (_Unchecked_test(__i))
	  __s[_Nb - 1 - __i] = '1';
    }

  // 23.3.5.3 bitset operations:
  template<size_t _Nb>
    inline bitset<_Nb> 
    operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y) 
    {
      bitset<_Nb> __result(__x);
      __result &= __y;
      return __result;
    }

  template<size_t _Nb>
    inline bitset<_Nb> 
    operator|(const bitset<_Nb>& __x, const bitset<_Nb>& __y) 
    {
      bitset<_Nb> __result(__x);
      __result |= __y;
      return __result;
    }

  template <size_t _Nb>
    inline bitset<_Nb> 
    operator^(const bitset<_Nb>& __x, const bitset<_Nb>& __y) 
    {
      bitset<_Nb> __result(__x);
      __result ^= __y;
      return __result;
    }

  template<class _CharT, class _Traits, size_t _Nb>
    basic_istream<_CharT, _Traits>&
    operator>>(basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
    {
      typedef typename _Traits::char_type char_type;
      basic_string<_CharT, _Traits> __tmp;
      __tmp.reserve(_Nb);
      
      // Skip whitespace
      typename basic_istream<_CharT, _Traits>::sentry __sentry(__is);
      if (__sentry) 
	{
	  basic_streambuf<_CharT, _Traits>* __buf = __is.rdbuf();
	  for (size_t __i = 0; __i < _Nb; ++__i) 
	    {
	      static typename _Traits::int_type __eof = _Traits::eof();
	      
	      typename _Traits::int_type __c1 = __buf->sbumpc();
	      if (_Traits::eq_int_type(__c1, __eof)) 
		{
		  __is.setstate(ios_base::eofbit);
		  break;
		}
	      else 
		{
		  char_type __c2 = _Traits::to_char_type(__c1);
		  char_type __c  = __is.narrow(__c2, '*');
		  
		  if (__c == '0' || __c == '1')
		    __tmp.push_back(__c);
		  else if (_Traits::eq_int_type(__buf->sputbackc(__c2), 
						__eof)) 
		    {
		      __is.setstate(ios_base::failbit);
		      break;
		    }
		}
	    }
	  
	  if (__tmp.empty())
	    __is.setstate(ios_base::failbit);
	  else
	    __x._M_copy_from_string(__tmp, static_cast<size_t>(0), _Nb);
	}

      return __is;
    }

  template <class _CharT, class _Traits, size_t _Nb>
    basic_ostream<_CharT, _Traits>&
    operator<<(basic_ostream<_CharT, _Traits>& __os, const bitset<_Nb>& __x)
    {
      basic_string<_CharT, _Traits> __tmp;
      __x._M_copy_to_string(__tmp);
      return __os << __tmp;
    }
} // namespace std

#undef __BITSET_WORDS

#endif