bitset

Go to the documentation of this file.
00001 // <bitset> -*- C++ -*-
00002 
00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 3, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // Under Section 7 of GPL version 3, you are granted additional
00018 // permissions described in the GCC Runtime Library Exception, version
00019 // 3.1, as published by the Free Software Foundation.
00020 
00021 // You should have received a copy of the GNU General Public License and
00022 // a copy of the GCC Runtime Library Exception along with this program;
00023 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00024 // <http://www.gnu.org/licenses/>.
00025 
00026 /*
00027  * Copyright (c) 1998
00028  * Silicon Graphics Computer Systems, Inc.
00029  *
00030  * Permission to use, copy, modify, distribute and sell this software
00031  * and its documentation for any purpose is hereby granted without fee,
00032  * provided that the above copyright notice appear in all copies and
00033  * that both that copyright notice and this permission notice appear
00034  * in supporting documentation.  Silicon Graphics makes no
00035  * representations about the suitability of this software for any
00036  * purpose.  It is provided "as is" without express or implied warranty.
00037  */
00038 
00039 /** @file include/bitset
00040  *  This is a Standard C++ Library header.
00041  */
00042 
00043 #ifndef _GLIBCXX_BITSET
00044 #define _GLIBCXX_BITSET 1
00045 
00046 #pragma GCC system_header
00047 
00048 #include <cstddef>     // For size_t
00049 #include <string>
00050 #include <bits/functexcept.h>   // For invalid_argument, out_of_range,
00051                                 // overflow_error
00052 #include <iosfwd>
00053 #include <cxxabi-forced.h>
00054 
00055 #define _GLIBCXX_BITSET_BITS_PER_WORD  (__CHAR_BIT__ * sizeof(unsigned long))
00056 #define _GLIBCXX_BITSET_WORDS(__n) \
00057  ((__n) < 1 ? 0 : ((__n) + _GLIBCXX_BITSET_BITS_PER_WORD - 1) \
00058                   / _GLIBCXX_BITSET_BITS_PER_WORD)
00059 
00060 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
00061 
00062   /**
00063    *  Base class, general case.  It is a class invariant that _Nw will be
00064    *  nonnegative.
00065    *
00066    *  See documentation for bitset.
00067   */
00068   template<size_t _Nw>
00069     struct _Base_bitset
00070     {
00071       typedef unsigned long _WordT;
00072 
00073       /// 0 is the least significant word.
00074       _WordT        _M_w[_Nw];
00075 
00076       _Base_bitset()
00077       { _M_do_reset(); }
00078 
00079 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00080       _Base_bitset(unsigned long long __val)
00081 #else
00082       _Base_bitset(unsigned long __val)
00083 #endif
00084       {
00085     _M_do_reset();
00086     _M_w[0] = __val;
00087 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00088     if (sizeof(unsigned long long) > sizeof(unsigned long))
00089       _M_w[1] = __val >> _GLIBCXX_BITSET_BITS_PER_WORD;
00090 #endif
00091       }
00092 
00093       static size_t
00094       _S_whichword(size_t __pos )
00095       { return __pos / _GLIBCXX_BITSET_BITS_PER_WORD; }
00096 
00097       static size_t
00098       _S_whichbyte(size_t __pos )
00099       { return (__pos % _GLIBCXX_BITSET_BITS_PER_WORD) / __CHAR_BIT__; }
00100 
00101       static size_t
00102       _S_whichbit(size_t __pos )
00103       { return __pos % _GLIBCXX_BITSET_BITS_PER_WORD; }
00104 
00105       static _WordT
00106       _S_maskbit(size_t __pos )
00107       { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
00108 
00109       _WordT&
00110       _M_getword(size_t __pos)
00111       { return _M_w[_S_whichword(__pos)]; }
00112 
00113       _WordT
00114       _M_getword(size_t __pos) const
00115       { return _M_w[_S_whichword(__pos)]; }
00116 
00117 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00118       const _WordT*
00119       _M_getdata() const
00120       { return _M_w; }
00121 #endif
00122 
00123       _WordT&
00124       _M_hiword()
00125       { return _M_w[_Nw - 1]; }
00126 
00127       _WordT
00128       _M_hiword() const
00129       { return _M_w[_Nw - 1]; }
00130 
00131       void
00132       _M_do_and(const _Base_bitset<_Nw>& __x)
00133       {
00134     for (size_t __i = 0; __i < _Nw; __i++)
00135       _M_w[__i] &= __x._M_w[__i];
00136       }
00137 
00138       void
00139       _M_do_or(const _Base_bitset<_Nw>& __x)
00140       {
00141     for (size_t __i = 0; __i < _Nw; __i++)
00142       _M_w[__i] |= __x._M_w[__i];
00143       }
00144 
00145       void
00146       _M_do_xor(const _Base_bitset<_Nw>& __x)
00147       {
00148     for (size_t __i = 0; __i < _Nw; __i++)
00149       _M_w[__i] ^= __x._M_w[__i];
00150       }
00151 
00152       void
00153       _M_do_left_shift(size_t __shift);
00154 
00155       void
00156       _M_do_right_shift(size_t __shift);
00157 
00158       void
00159       _M_do_flip()
00160       {
00161     for (size_t __i = 0; __i < _Nw; __i++)
00162       _M_w[__i] = ~_M_w[__i];
00163       }
00164 
00165       void
00166       _M_do_set()
00167       {
00168     for (size_t __i = 0; __i < _Nw; __i++)
00169       _M_w[__i] = ~static_cast<_WordT>(0);
00170       }
00171 
00172       void
00173       _M_do_reset()
00174       { __builtin_memset(_M_w, 0, _Nw * sizeof(_WordT)); }
00175 
00176       bool
00177       _M_is_equal(const _Base_bitset<_Nw>& __x) const
00178       {
00179     for (size_t __i = 0; __i < _Nw; ++__i)
00180       if (_M_w[__i] != __x._M_w[__i])
00181         return false;
00182     return true;
00183       }
00184 
00185       size_t
00186       _M_are_all_aux() const
00187       {
00188     for (size_t __i = 0; __i < _Nw - 1; __i++)
00189       if (_M_w[__i] != ~static_cast<_WordT>(0))
00190         return 0;
00191     return ((_Nw - 1) * _GLIBCXX_BITSET_BITS_PER_WORD
00192         + __builtin_popcountl(_M_hiword()));
00193       }
00194 
00195       bool
00196       _M_is_any() const
00197       {
00198     for (size_t __i = 0; __i < _Nw; __i++)
00199       if (_M_w[__i] != static_cast<_WordT>(0))
00200         return true;
00201     return false;
00202       }
00203 
00204       size_t
00205       _M_do_count() const
00206       {
00207     size_t __result = 0;
00208     for (size_t __i = 0; __i < _Nw; __i++)
00209       __result += __builtin_popcountl(_M_w[__i]);
00210     return __result;
00211       }
00212 
00213       unsigned long
00214       _M_do_to_ulong() const;
00215 
00216 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00217       unsigned long long
00218       _M_do_to_ullong() const;
00219 #endif
00220 
00221       // find first "on" bit
00222       size_t
00223       _M_do_find_first(size_t __not_found) const;
00224 
00225       // find the next "on" bit that follows "prev"
00226       size_t
00227       _M_do_find_next(size_t __prev, size_t __not_found) const;
00228     };
00229 
00230   // Definitions of non-inline functions from _Base_bitset.
00231   template<size_t _Nw>
00232     void
00233     _Base_bitset<_Nw>::_M_do_left_shift(size_t __shift)
00234     {
00235       if (__builtin_expect(__shift != 0, 1))
00236     {
00237       const size_t __wshift = __shift / _GLIBCXX_BITSET_BITS_PER_WORD;
00238       const size_t __offset = __shift % _GLIBCXX_BITSET_BITS_PER_WORD;
00239 
00240       if (__offset == 0)
00241         for (size_t __n = _Nw - 1; __n >= __wshift; --__n)
00242           _M_w[__n] = _M_w[__n - __wshift];
00243       else
00244         {
00245           const size_t __sub_offset = (_GLIBCXX_BITSET_BITS_PER_WORD 
00246                        - __offset);
00247           for (size_t __n = _Nw - 1; __n > __wshift; --__n)
00248         _M_w[__n] = ((_M_w[__n - __wshift] << __offset)
00249                  | (_M_w[__n - __wshift - 1] >> __sub_offset));
00250           _M_w[__wshift] = _M_w[0] << __offset;
00251         }
00252 
00253       std::fill(_M_w + 0, _M_w + __wshift, static_cast<_WordT>(0));
00254     }
00255     }
00256 
00257   template<size_t _Nw>
00258     void
00259     _Base_bitset<_Nw>::_M_do_right_shift(size_t __shift)
00260     {
00261       if (__builtin_expect(__shift != 0, 1))
00262     {
00263       const size_t __wshift = __shift / _GLIBCXX_BITSET_BITS_PER_WORD;
00264       const size_t __offset = __shift % _GLIBCXX_BITSET_BITS_PER_WORD;
00265       const size_t __limit = _Nw - __wshift - 1;
00266 
00267       if (__offset == 0)
00268         for (size_t __n = 0; __n <= __limit; ++__n)
00269           _M_w[__n] = _M_w[__n + __wshift];
00270       else
00271         {
00272           const size_t __sub_offset = (_GLIBCXX_BITSET_BITS_PER_WORD
00273                        - __offset);
00274           for (size_t __n = 0; __n < __limit; ++__n)
00275         _M_w[__n] = ((_M_w[__n + __wshift] >> __offset)
00276                  | (_M_w[__n + __wshift + 1] << __sub_offset));
00277           _M_w[__limit] = _M_w[_Nw-1] >> __offset;
00278         }
00279       
00280       std::fill(_M_w + __limit + 1, _M_w + _Nw, static_cast<_WordT>(0));
00281     }
00282     }
00283 
00284   template<size_t _Nw>
00285     unsigned long
00286     _Base_bitset<_Nw>::_M_do_to_ulong() const
00287     {
00288       for (size_t __i = 1; __i < _Nw; ++__i)
00289     if (_M_w[__i])
00290       __throw_overflow_error(__N("_Base_bitset::_M_do_to_ulong"));
00291       return _M_w[0];
00292     }
00293 
00294 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00295   template<size_t _Nw>
00296     unsigned long long
00297     _Base_bitset<_Nw>::_M_do_to_ullong() const
00298     {
00299       const bool __dw = sizeof(unsigned long long) > sizeof(unsigned long);
00300       for (size_t __i = 1 + __dw; __i < _Nw; ++__i)
00301     if (_M_w[__i])
00302       __throw_overflow_error(__N("_Base_bitset::_M_do_to_ullong"));
00303 
00304       if (__dw)
00305     return _M_w[0] + (static_cast<unsigned long long>(_M_w[1])
00306               << _GLIBCXX_BITSET_BITS_PER_WORD);
00307       return _M_w[0];
00308     }
00309 #endif
00310 
00311   template<size_t _Nw>
00312     size_t
00313     _Base_bitset<_Nw>::_M_do_find_first(size_t __not_found) const
00314     {
00315       for (size_t __i = 0; __i < _Nw; __i++)
00316     {
00317       _WordT __thisword = _M_w[__i];
00318       if (__thisword != static_cast<_WordT>(0))
00319         return (__i * _GLIBCXX_BITSET_BITS_PER_WORD
00320             + __builtin_ctzl(__thisword));
00321     }
00322       // not found, so return an indication of failure.
00323       return __not_found;
00324     }
00325 
00326   template<size_t _Nw>
00327     size_t
00328     _Base_bitset<_Nw>::_M_do_find_next(size_t __prev, size_t __not_found) const
00329     {
00330       // make bound inclusive
00331       ++__prev;
00332 
00333       // check out of bounds
00334       if (__prev >= _Nw * _GLIBCXX_BITSET_BITS_PER_WORD)
00335     return __not_found;
00336 
00337       // search first word
00338       size_t __i = _S_whichword(__prev);
00339       _WordT __thisword = _M_w[__i];
00340 
00341       // mask off bits below bound
00342       __thisword &= (~static_cast<_WordT>(0)) << _S_whichbit(__prev);
00343 
00344       if (__thisword != static_cast<_WordT>(0))
00345     return (__i * _GLIBCXX_BITSET_BITS_PER_WORD
00346         + __builtin_ctzl(__thisword));
00347 
00348       // check subsequent words
00349       __i++;
00350       for (; __i < _Nw; __i++)
00351     {
00352       __thisword = _M_w[__i];
00353       if (__thisword != static_cast<_WordT>(0))
00354         return (__i * _GLIBCXX_BITSET_BITS_PER_WORD
00355             + __builtin_ctzl(__thisword));
00356     }
00357       // not found, so return an indication of failure.
00358       return __not_found;
00359     } // end _M_do_find_next
00360 
00361   /**
00362    *  Base class, specialization for a single word.
00363    *
00364    *  See documentation for bitset.
00365   */
00366   template<>
00367     struct _Base_bitset<1>
00368     {
00369       typedef unsigned long _WordT;
00370       _WordT _M_w;
00371 
00372       _Base_bitset(void)
00373       : _M_w(0)
00374       { }
00375 
00376 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00377       _Base_bitset(unsigned long long __val)
00378 #else
00379       _Base_bitset(unsigned long __val)
00380 #endif
00381       : _M_w(__val)
00382       { }
00383 
00384       static size_t
00385       _S_whichword(size_t __pos )
00386       { return __pos / _GLIBCXX_BITSET_BITS_PER_WORD; }
00387 
00388       static size_t
00389       _S_whichbyte(size_t __pos )
00390       { return (__pos % _GLIBCXX_BITSET_BITS_PER_WORD) / __CHAR_BIT__; }
00391 
00392       static size_t
00393       _S_whichbit(size_t __pos )
00394       {  return __pos % _GLIBCXX_BITSET_BITS_PER_WORD; }
00395 
00396       static _WordT
00397       _S_maskbit(size_t __pos )
00398       { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
00399 
00400       _WordT&
00401       _M_getword(size_t)
00402       { return _M_w; }
00403 
00404       _WordT
00405       _M_getword(size_t) const
00406       { return _M_w; }
00407 
00408 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00409       const _WordT*
00410       _M_getdata() const
00411       { return &_M_w; }
00412 #endif
00413 
00414       _WordT&
00415       _M_hiword()
00416       { return _M_w; }
00417 
00418       _WordT
00419       _M_hiword() const
00420       { return _M_w; }
00421 
00422       void
00423       _M_do_and(const _Base_bitset<1>& __x)
00424       { _M_w &= __x._M_w; }
00425 
00426       void
00427       _M_do_or(const _Base_bitset<1>& __x)
00428       { _M_w |= __x._M_w; }
00429 
00430       void
00431       _M_do_xor(const _Base_bitset<1>& __x)
00432       { _M_w ^= __x._M_w; }
00433 
00434       void
00435       _M_do_left_shift(size_t __shift)
00436       { _M_w <<= __shift; }
00437 
00438       void
00439       _M_do_right_shift(size_t __shift)
00440       { _M_w >>= __shift; }
00441 
00442       void
00443       _M_do_flip()
00444       { _M_w = ~_M_w; }
00445 
00446       void
00447       _M_do_set()
00448       { _M_w = ~static_cast<_WordT>(0); }
00449 
00450       void
00451       _M_do_reset()
00452       { _M_w = 0; }
00453 
00454       bool
00455       _M_is_equal(const _Base_bitset<1>& __x) const
00456       { return _M_w == __x._M_w; }
00457 
00458       size_t
00459       _M_are_all_aux() const
00460       { return __builtin_popcountl(_M_w); }
00461 
00462       bool
00463       _M_is_any() const
00464       { return _M_w != 0; }
00465 
00466       size_t
00467       _M_do_count() const
00468       { return __builtin_popcountl(_M_w); }
00469 
00470       unsigned long
00471       _M_do_to_ulong() const
00472       { return _M_w; }
00473 
00474 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00475       unsigned long long
00476       _M_do_to_ullong() const
00477       { return _M_w; }
00478 #endif
00479 
00480       size_t
00481       _M_do_find_first(size_t __not_found) const
00482       {
00483         if (_M_w != 0)
00484           return __builtin_ctzl(_M_w);
00485         else
00486           return __not_found;
00487       }
00488 
00489       // find the next "on" bit that follows "prev"
00490       size_t
00491       _M_do_find_next(size_t __prev, size_t __not_found) const
00492       {
00493     ++__prev;
00494     if (__prev >= ((size_t) _GLIBCXX_BITSET_BITS_PER_WORD))
00495       return __not_found;
00496 
00497     _WordT __x = _M_w >> __prev;
00498     if (__x != 0)
00499       return __builtin_ctzl(__x) + __prev;
00500     else
00501       return __not_found;
00502       }
00503     };
00504 
00505   /**
00506    *  Base class, specialization for no storage (zero-length %bitset).
00507    *
00508    *  See documentation for bitset.
00509   */
00510   template<>
00511     struct _Base_bitset<0>
00512     {
00513       typedef unsigned long _WordT;
00514 
00515       _Base_bitset()
00516       { }
00517 
00518 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00519       _Base_bitset(unsigned long long)
00520 #else
00521       _Base_bitset(unsigned long)
00522 #endif
00523       { }
00524 
00525       static size_t
00526       _S_whichword(size_t __pos )
00527       { return __pos / _GLIBCXX_BITSET_BITS_PER_WORD; }
00528 
00529       static size_t
00530       _S_whichbyte(size_t __pos )
00531       { return (__pos % _GLIBCXX_BITSET_BITS_PER_WORD) / __CHAR_BIT__; }
00532 
00533       static size_t
00534       _S_whichbit(size_t __pos )
00535       {  return __pos % _GLIBCXX_BITSET_BITS_PER_WORD; }
00536 
00537       static _WordT
00538       _S_maskbit(size_t __pos )
00539       { return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
00540 
00541       // This would normally give access to the data.  The bounds-checking
00542       // in the bitset class will prevent the user from getting this far,
00543       // but (1) it must still return an lvalue to compile, and (2) the
00544       // user might call _Unchecked_set directly, in which case this /needs/
00545       // to fail.  Let's not penalize zero-length users unless they actually
00546       // make an unchecked call; all the memory ugliness is therefore
00547       // localized to this single should-never-get-this-far function.
00548       _WordT&
00549       _M_getword(size_t) const
00550       { 
00551     __throw_out_of_range(__N("_Base_bitset::_M_getword")); 
00552     return *new _WordT; 
00553       }
00554 
00555       _WordT
00556       _M_hiword() const
00557       { return 0; }
00558 
00559       void
00560       _M_do_and(const _Base_bitset<0>&)
00561       { }
00562 
00563       void
00564       _M_do_or(const _Base_bitset<0>&)
00565       { }
00566 
00567       void
00568       _M_do_xor(const _Base_bitset<0>&)
00569       { }
00570 
00571       void
00572       _M_do_left_shift(size_t)
00573       { }
00574 
00575       void
00576       _M_do_right_shift(size_t)
00577       { }
00578 
00579       void
00580       _M_do_flip()
00581       { }
00582 
00583       void
00584       _M_do_set()
00585       { }
00586 
00587       void
00588       _M_do_reset()
00589       { }
00590 
00591       // Are all empty bitsets equal to each other?  Are they equal to
00592       // themselves?  How to compare a thing which has no state?  What is
00593       // the sound of one zero-length bitset clapping?
00594       bool
00595       _M_is_equal(const _Base_bitset<0>&) const
00596       { return true; }
00597 
00598       size_t
00599       _M_are_all_aux() const
00600       { return 0; }
00601 
00602       bool
00603       _M_is_any() const
00604       { return false; }
00605 
00606       size_t
00607       _M_do_count() const
00608       { return 0; }
00609 
00610       unsigned long
00611       _M_do_to_ulong() const
00612       { return 0; }
00613 
00614 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00615       unsigned long long
00616       _M_do_to_ullong() const
00617       { return 0; }
00618 #endif
00619 
00620       // Normally "not found" is the size, but that could also be
00621       // misinterpreted as an index in this corner case.  Oh well.
00622       size_t
00623       _M_do_find_first(size_t) const
00624       { return 0; }
00625 
00626       size_t
00627       _M_do_find_next(size_t, size_t) const
00628       { return 0; }
00629     };
00630 
00631 
00632   // Helper class to zero out the unused high-order bits in the highest word.
00633   template<size_t _Extrabits>
00634     struct _Sanitize
00635     {
00636       static void _S_do_sanitize(unsigned long& __val)
00637       { __val &= ~((~static_cast<unsigned long>(0)) << _Extrabits); }
00638     };
00639 
00640   template<>
00641     struct _Sanitize<0>
00642     { static void _S_do_sanitize(unsigned long) {} };
00643 
00644   /**
00645    *  @brief  The %bitset class represents a @e fixed-size sequence of bits.
00646    *
00647    *  @ingroup containers
00648    *
00649    *  (Note that %bitset does @e not meet the formal requirements of a
00650    *  <a href="tables.html#65">container</a>.  Mainly, it lacks iterators.)
00651    *
00652    *  The template argument, @a Nb, may be any non-negative number,
00653    *  specifying the number of bits (e.g., "0", "12", "1024*1024").
00654    *
00655    *  In the general unoptimized case, storage is allocated in word-sized
00656    *  blocks.  Let B be the number of bits in a word, then (Nb+(B-1))/B
00657    *  words will be used for storage.  B - Nb%B bits are unused.  (They are
00658    *  the high-order bits in the highest word.)  It is a class invariant
00659    *  that those unused bits are always zero.
00660    *
00661    *  If you think of %bitset as <em>a simple array of bits</em>, be
00662    *  aware that your mental picture is reversed: a %bitset behaves
00663    *  the same way as bits in integers do, with the bit at index 0 in
00664    *  the <em>least significant / right-hand</em> position, and the bit at
00665    *  index Nb-1 in the <em>most significant / left-hand</em> position.
00666    *  Thus, unlike other containers, a %bitset's index <em>counts from
00667    *  right to left</em>, to put it very loosely.
00668    *
00669    *  This behavior is preserved when translating to and from strings.  For
00670    *  example, the first line of the following program probably prints
00671    *  <em>b(&apos;a&apos;) is 0001100001</em> on a modern ASCII system.
00672    *
00673    *  @code
00674    *     #include <bitset>
00675    *     #include <iostream>
00676    *     #include <sstream>
00677    *
00678    *     using namespace std;
00679    *
00680    *     int main()
00681    *     {
00682    *         long         a = 'a';
00683    *         bitset<10>   b(a);
00684    *
00685    *         cout << "b('a') is " << b << endl;
00686    *
00687    *         ostringstream s;
00688    *         s << b;
00689    *         string  str = s.str();
00690    *         cout << "index 3 in the string is " << str[3] << " but\n"
00691    *              << "index 3 in the bitset is " << b[3] << endl;
00692    *     }
00693    *  @endcode
00694    *
00695    *  Also see:
00696    *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch33s02.html
00697    *  for a description of extensions.
00698    *
00699    *  Most of the actual code isn't contained in %bitset<> itself, but in the
00700    *  base class _Base_bitset.  The base class works with whole words, not with
00701    *  individual bits.  This allows us to specialize _Base_bitset for the
00702    *  important special case where the %bitset is only a single word.
00703    *
00704    *  Extra confusion can result due to the fact that the storage for
00705    *  _Base_bitset @e is a regular array, and is indexed as such.  This is
00706    *  carefully encapsulated.
00707   */
00708   template<size_t _Nb>
00709     class bitset
00710     : private _Base_bitset<_GLIBCXX_BITSET_WORDS(_Nb)>
00711     {
00712     private:
00713       typedef _Base_bitset<_GLIBCXX_BITSET_WORDS(_Nb)> _Base;
00714       typedef unsigned long _WordT;
00715 
00716       void
00717     _M_do_sanitize()
00718     {
00719       _Sanitize<_Nb % _GLIBCXX_BITSET_BITS_PER_WORD>::
00720         _S_do_sanitize(this->_M_hiword());
00721     }
00722 
00723 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00724       template<typename> friend class hash;
00725 #endif
00726 
00727     public:
00728       /**
00729        *  This encapsulates the concept of a single bit.  An instance of this
00730        *  class is a proxy for an actual bit; this way the individual bit
00731        *  operations are done as faster word-size bitwise instructions.
00732        *
00733        *  Most users will never need to use this class directly; conversions
00734        *  to and from bool are automatic and should be transparent.  Overloaded
00735        *  operators help to preserve the illusion.
00736        *
00737        *  (On a typical system, this <em>bit %reference</em> is 64
00738        *  times the size of an actual bit.  Ha.)
00739        */
00740       class reference
00741       {
00742     friend class bitset;
00743 
00744     _WordT *_M_wp;
00745     size_t _M_bpos;
00746     
00747     // left undefined
00748     reference();
00749     
00750       public:
00751     reference(bitset& __b, size_t __pos)
00752     {
00753       _M_wp = &__b._M_getword(__pos);
00754       _M_bpos = _Base::_S_whichbit(__pos);
00755     }
00756 
00757     ~reference()
00758     { }
00759 
00760     // For b[i] = __x;
00761     reference&
00762     operator=(bool __x)
00763     {
00764       if (__x)
00765         *_M_wp |= _Base::_S_maskbit(_M_bpos);
00766       else
00767         *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
00768       return *this;
00769     }
00770 
00771     // For b[i] = b[__j];
00772     reference&
00773     operator=(const reference& __j)
00774     {
00775       if ((*(__j._M_wp) & _Base::_S_maskbit(__j._M_bpos)))
00776         *_M_wp |= _Base::_S_maskbit(_M_bpos);
00777       else
00778         *_M_wp &= ~_Base::_S_maskbit(_M_bpos);
00779       return *this;
00780     }
00781 
00782     // Flips the bit
00783     bool
00784     operator~() const
00785     { return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) == 0; }
00786 
00787     // For __x = b[i];
00788     operator bool() const
00789     { return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) != 0; }
00790 
00791     // For b[i].flip();
00792     reference&
00793     flip()
00794     {
00795       *_M_wp ^= _Base::_S_maskbit(_M_bpos);
00796       return *this;
00797     }
00798       };
00799       friend class reference;
00800 
00801       // 23.3.5.1 constructors:
00802       /// All bits set to zero.
00803       bitset()
00804       { }
00805 
00806       /// Initial bits bitwise-copied from a single word (others set to zero).
00807 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00808       bitset(unsigned long long __val)
00809 #else
00810       bitset(unsigned long __val)
00811 #endif
00812       : _Base(__val)
00813       { _M_do_sanitize(); }
00814 
00815       /**
00816        *  @brief  Use a subset of a string.
00817        *  @param  s  A string of @a 0 and @a 1 characters.
00818        *  @param  position  Index of the first character in @a s to use;
00819        *                    defaults to zero.
00820        *  @throw  std::out_of_range  If @a pos is bigger the size of @a s.
00821        *  @throw  std::invalid_argument  If a character appears in the string
00822        *                                 which is neither @a 0 nor @a 1.
00823        */
00824       template<class _CharT, class _Traits, class _Alloc>
00825     explicit
00826     bitset(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
00827            size_t __position = 0)
00828     : _Base()
00829     {
00830       if (__position > __s.size())
00831         __throw_out_of_range(__N("bitset::bitset initial position "
00832                      "not valid"));
00833       _M_copy_from_string(__s, __position,
00834                   std::basic_string<_CharT, _Traits, _Alloc>::npos,
00835                   _CharT('0'), _CharT('1'));
00836     }
00837 
00838       /**
00839        *  @brief  Use a subset of a string.
00840        *  @param  s  A string of @a 0 and @a 1 characters.
00841        *  @param  position  Index of the first character in @a s to use.
00842        *  @param  n    The number of characters to copy.
00843        *  @throw  std::out_of_range  If @a pos is bigger the size of @a s.
00844        *  @throw  std::invalid_argument  If a character appears in the string
00845        *                                 which is neither @a 0 nor @a 1.
00846        */
00847       template<class _CharT, class _Traits, class _Alloc>
00848     bitset(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
00849            size_t __position, size_t __n)
00850     : _Base()
00851     {
00852       if (__position > __s.size())
00853         __throw_out_of_range(__N("bitset::bitset initial position "
00854                      "not valid"));
00855       _M_copy_from_string(__s, __position, __n, _CharT('0'), _CharT('1'));
00856     }
00857 
00858       // _GLIBCXX_RESOLVE_LIB_DEFECTS
00859       // 396. what are characters zero and one.
00860       template<class _CharT, class _Traits, class _Alloc>
00861     bitset(const std::basic_string<_CharT, _Traits, _Alloc>& __s,
00862            size_t __position, size_t __n,
00863            _CharT __zero, _CharT __one = _CharT('1'))
00864     : _Base()
00865     {
00866       if (__position > __s.size())
00867         __throw_out_of_range(__N("bitset::bitset initial position "
00868                      "not valid"));
00869       _M_copy_from_string(__s, __position, __n, __zero, __one);
00870     }
00871 
00872 #ifdef __GXX_EXPERIMENTAL_CXX0X__
00873       /**
00874        *  @brief  Construct from a string.
00875        *  @param  str  A string of @a 0 and @a 1 characters.
00876        *  @throw  std::invalid_argument  If a character appears in the string
00877        *                                 which is neither @a 0 nor @a 1.
00878        */
00879       explicit
00880       bitset(const char* __str)
00881       : _Base()
00882       {
00883     if (!__str)
00884       __throw_logic_error(__N("bitset::bitset(const char*)"));
00885 
00886     const size_t __len = __builtin_strlen(__str);
00887     _M_copy_from_ptr<char, std::char_traits<char>>(__str, __len, 0,
00888                                __len, '0', '1');
00889       }
00890 #endif
00891 
00892       // 23.3.5.2 bitset operations:
00893       //@{
00894       /**
00895        *  @brief  Operations on bitsets.
00896        *  @param  rhs  A same-sized bitset.
00897        *
00898        *  These should be self-explanatory.
00899        */
00900       bitset<_Nb>&
00901       operator&=(const bitset<_Nb>& __rhs)
00902       {
00903     this->_M_do_and(__rhs);
00904     return *this;
00905       }
00906 
00907       bitset<_Nb>&
00908       operator|=(const bitset<_Nb>& __rhs)
00909       {
00910     this->_M_do_or(__rhs);
00911     return *this;
00912       }
00913 
00914       bitset<_Nb>&
00915       operator^=(const bitset<_Nb>& __rhs)
00916       {
00917     this->_M_do_xor(__rhs);
00918     return *this;
00919       }
00920       //@}
00921       
00922       //@{
00923       /**
00924        *  @brief  Operations on bitsets.
00925        *  @param  position  The number of places to shift.
00926        *
00927        *  These should be self-explanatory.
00928        */
00929       bitset<_Nb>&
00930       operator<<=(size_t __position)
00931       {
00932     if (__builtin_expect(__position < _Nb, 1))
00933       {
00934         this->_M_do_left_shift(__position);
00935         this->_M_do_sanitize();
00936       }
00937     else
00938       this->_M_do_reset();
00939     return *this;
00940       }
00941 
00942       bitset<_Nb>&
00943       operator>>=(size_t __position)
00944       {
00945     if (__builtin_expect(__position < _Nb, 1))
00946       {
00947         this->_M_do_right_shift(__position);
00948         this->_M_do_sanitize();
00949       }
00950     else
00951       this->_M_do_reset();
00952     return *this;
00953       }
00954       //@}
00955       
00956       //@{
00957       /**
00958        *  These versions of single-bit set, reset, flip, and test are
00959        *  extensions from the SGI version.  They do no range checking.
00960        *  @ingroup SGIextensions
00961        */
00962       bitset<_Nb>&
00963       _Unchecked_set(size_t __pos)
00964       {
00965     this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
00966     return *this;
00967       }
00968 
00969       bitset<_Nb>&
00970       _Unchecked_set(size_t __pos, int __val)
00971       {
00972     if (__val)
00973       this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
00974     else
00975       this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
00976     return *this;
00977       }
00978 
00979       bitset<_Nb>&
00980       _Unchecked_reset(size_t __pos)
00981       {
00982     this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
00983     return *this;
00984       }
00985 
00986       bitset<_Nb>&
00987       _Unchecked_flip(size_t __pos)
00988       {
00989     this->_M_getword(__pos) ^= _Base::_S_maskbit(__pos);
00990     return *this;
00991       }
00992 
00993       bool
00994       _Unchecked_test(size_t __pos) const
00995       { return ((this->_M_getword(__pos) & _Base::_S_maskbit(__pos))
00996         != static_cast<_WordT>(0)); }
00997       //@}
00998       
00999       // Set, reset, and flip.
01000       /**
01001        *  @brief Sets every bit to true.
01002        */
01003       bitset<_Nb>&
01004       set()
01005       {
01006     this->_M_do_set();
01007     this->_M_do_sanitize();
01008     return *this;
01009       }
01010 
01011       /**
01012        *  @brief Sets a given bit to a particular value.
01013        *  @param  position  The index of the bit.
01014        *  @param  val  Either true or false, defaults to true.
01015        *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
01016        */
01017       bitset<_Nb>&
01018       set(size_t __position, bool __val = true)
01019       {
01020     if (__position >= _Nb)
01021       __throw_out_of_range(__N("bitset::set"));
01022     return _Unchecked_set(__position, __val);
01023       }
01024 
01025       /**
01026        *  @brief Sets every bit to false.
01027        */
01028       bitset<_Nb>&
01029       reset()
01030       {
01031     this->_M_do_reset();
01032     return *this;
01033       }
01034 
01035       /**
01036        *  @brief Sets a given bit to false.
01037        *  @param  position  The index of the bit.
01038        *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
01039        *
01040        *  Same as writing @c set(pos,false).
01041        */
01042       bitset<_Nb>&
01043       reset(size_t __position)
01044       {
01045     if (__position >= _Nb)
01046       __throw_out_of_range(__N("bitset::reset"));
01047     return _Unchecked_reset(__position);
01048       }
01049       
01050       /**
01051        *  @brief Toggles every bit to its opposite value.
01052        */
01053       bitset<_Nb>&
01054       flip()
01055       {
01056     this->_M_do_flip();
01057     this->_M_do_sanitize();
01058     return *this;
01059       }
01060 
01061       /**
01062        *  @brief Toggles a given bit to its opposite value.
01063        *  @param  position  The index of the bit.
01064        *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
01065        */
01066       bitset<_Nb>&
01067       flip(size_t __position)
01068       {
01069     if (__position >= _Nb)
01070       __throw_out_of_range(__N("bitset::flip"));
01071     return _Unchecked_flip(__position);
01072       }
01073       
01074       /// See the no-argument flip().
01075       bitset<_Nb>
01076       operator~() const
01077       { return bitset<_Nb>(*this).flip(); }
01078 
01079       //@{
01080       /**
01081        *  @brief  Array-indexing support.
01082        *  @param  position  Index into the %bitset.
01083        *  @return  A bool for a <em>const %bitset</em>.  For non-const bitsets, an
01084        *           instance of the reference proxy class.
01085        *  @note  These operators do no range checking and throw no exceptions,
01086        *         as required by DR 11 to the standard.
01087        *
01088        *  _GLIBCXX_RESOLVE_LIB_DEFECTS Note that this implementation already
01089        *  resolves DR 11 (items 1 and 2), but does not do the range-checking
01090        *  required by that DR's resolution.  -pme
01091        *  The DR has since been changed:  range-checking is a precondition
01092        *  (users' responsibility), and these functions must not throw.  -pme
01093        */
01094       reference
01095       operator[](size_t __position)
01096       { return reference(*this,__position); }
01097 
01098       bool
01099       operator[](size_t __position) const
01100       { return _Unchecked_test(__position); }
01101       //@}
01102       
01103       /**
01104        *  @brief Returns a numerical interpretation of the %bitset.
01105        *  @return  The integral equivalent of the bits.
01106        *  @throw  std::overflow_error  If there are too many bits to be
01107        *                               represented in an @c unsigned @c long.
01108        */
01109       unsigned long
01110       to_ulong() const
01111       { return this->_M_do_to_ulong(); }
01112 
01113 #ifdef __GXX_EXPERIMENTAL_CXX0X__
01114       unsigned long long
01115       to_ullong() const
01116       { return this->_M_do_to_ullong(); }
01117 #endif
01118 
01119       /**
01120        *  @brief Returns a character interpretation of the %bitset.
01121        *  @return  The string equivalent of the bits.
01122        *
01123        *  Note the ordering of the bits:  decreasing character positions
01124        *  correspond to increasing bit positions (see the main class notes for
01125        *  an example).
01126        */
01127       template<class _CharT, class _Traits, class _Alloc>
01128     std::basic_string<_CharT, _Traits, _Alloc>
01129     to_string() const
01130     {
01131       std::basic_string<_CharT, _Traits, _Alloc> __result;
01132       _M_copy_to_string(__result, _CharT('0'), _CharT('1'));
01133       return __result;
01134     }
01135 
01136       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01137       // 396. what are characters zero and one.
01138       template<class _CharT, class _Traits, class _Alloc>
01139     std::basic_string<_CharT, _Traits, _Alloc>
01140     to_string(_CharT __zero, _CharT __one = _CharT('1')) const
01141     {
01142       std::basic_string<_CharT, _Traits, _Alloc> __result;
01143       _M_copy_to_string(__result, __zero, __one);
01144       return __result;
01145     }
01146 
01147       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01148       // 434. bitset::to_string() hard to use.
01149       template<class _CharT, class _Traits>
01150     std::basic_string<_CharT, _Traits, std::allocator<_CharT> >
01151     to_string() const
01152     { return to_string<_CharT, _Traits, std::allocator<_CharT> >(); }
01153 
01154       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01155       // 853. to_string needs updating with zero and one.
01156       template<class _CharT, class _Traits>
01157     std::basic_string<_CharT, _Traits, std::allocator<_CharT> >
01158     to_string(_CharT __zero, _CharT __one = _CharT('1')) const
01159     { return to_string<_CharT, _Traits,
01160                        std::allocator<_CharT> >(__zero, __one); }
01161 
01162       template<class _CharT>
01163     std::basic_string<_CharT, std::char_traits<_CharT>,
01164                       std::allocator<_CharT> >
01165     to_string() const
01166     {
01167       return to_string<_CharT, std::char_traits<_CharT>,
01168                        std::allocator<_CharT> >();
01169     }
01170 
01171       template<class _CharT>
01172     std::basic_string<_CharT, std::char_traits<_CharT>,
01173                       std::allocator<_CharT> >
01174     to_string(_CharT __zero, _CharT __one = _CharT('1')) const
01175     {
01176       return to_string<_CharT, std::char_traits<_CharT>,
01177                        std::allocator<_CharT> >(__zero, __one);
01178     }
01179 
01180       std::basic_string<char, std::char_traits<char>, std::allocator<char> >
01181       to_string() const
01182       {
01183     return to_string<char, std::char_traits<char>,
01184                      std::allocator<char> >();
01185       }
01186 
01187       std::basic_string<char, std::char_traits<char>, std::allocator<char> >
01188       to_string(char __zero, char __one = '1') const
01189       {
01190     return to_string<char, std::char_traits<char>,
01191                      std::allocator<char> >(__zero, __one);
01192       }
01193 
01194       // Helper functions for string operations.
01195       template<class _CharT, class _Traits>
01196         void
01197         _M_copy_from_ptr(const _CharT*, size_t, size_t, size_t,
01198              _CharT, _CharT);
01199 
01200       template<class _CharT, class _Traits, class _Alloc>
01201     void
01202     _M_copy_from_string(const std::basic_string<_CharT,
01203                 _Traits, _Alloc>& __s, size_t __pos, size_t __n,
01204                 _CharT __zero, _CharT __one)
01205     { _M_copy_from_ptr<_CharT, _Traits>(__s.data(), __s.size(), __pos, __n,
01206                         __zero, __one); }
01207 
01208       template<class _CharT, class _Traits, class _Alloc>
01209     void
01210         _M_copy_to_string(std::basic_string<_CharT, _Traits, _Alloc>&,
01211               _CharT, _CharT) const;
01212 
01213       // NB: Backward compat.
01214       template<class _CharT, class _Traits, class _Alloc>
01215     void
01216     _M_copy_from_string(const std::basic_string<_CharT,
01217                 _Traits, _Alloc>& __s, size_t __pos, size_t __n)
01218     { _M_copy_from_string(__s, __pos, __n, _CharT('0'), _CharT('1')); }
01219 
01220       template<class _CharT, class _Traits, class _Alloc>
01221     void
01222         _M_copy_to_string(std::basic_string<_CharT, _Traits,_Alloc>& __s) const
01223     { _M_copy_to_string(__s, _CharT('0'), _CharT('1')); }
01224 
01225       /// Returns the number of bits which are set.
01226       size_t
01227       count() const
01228       { return this->_M_do_count(); }
01229 
01230       /// Returns the total number of bits.
01231       size_t
01232       size() const
01233       { return _Nb; }
01234 
01235       //@{
01236       /// These comparisons for equality/inequality are, well, @e bitwise.
01237       bool
01238       operator==(const bitset<_Nb>& __rhs) const
01239       { return this->_M_is_equal(__rhs); }
01240 
01241       bool
01242       operator!=(const bitset<_Nb>& __rhs) const
01243       { return !this->_M_is_equal(__rhs); }
01244       //@}
01245       
01246       /**
01247        *  @brief Tests the value of a bit.
01248        *  @param  position  The index of a bit.
01249        *  @return  The value at @a pos.
01250        *  @throw  std::out_of_range  If @a pos is bigger the size of the %set.
01251        */
01252       bool
01253       test(size_t __position) const
01254       {
01255     if (__position >= _Nb)
01256       __throw_out_of_range(__N("bitset::test"));
01257     return _Unchecked_test(__position);
01258       }
01259 
01260       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01261       // DR 693. std::bitset::all() missing.
01262       /**
01263        *  @brief Tests whether all the bits are on.
01264        *  @return  True if all the bits are set.
01265        */
01266       bool
01267       all() const
01268       { return this->_M_are_all_aux() == _Nb; }
01269 
01270       /**
01271        *  @brief Tests whether any of the bits are on.
01272        *  @return  True if at least one bit is set.
01273        */
01274       bool
01275       any() const
01276       { return this->_M_is_any(); }
01277 
01278       /**
01279        *  @brief Tests whether any of the bits are on.
01280        *  @return  True if none of the bits are set.
01281        */
01282       bool
01283       none() const
01284       { return !this->_M_is_any(); }
01285 
01286       //@{
01287       /// Self-explanatory.
01288       bitset<_Nb>
01289       operator<<(size_t __position) const
01290       { return bitset<_Nb>(*this) <<= __position; }
01291 
01292       bitset<_Nb>
01293       operator>>(size_t __position) const
01294       { return bitset<_Nb>(*this) >>= __position; }
01295       //@}
01296       
01297       /**
01298        *  @brief  Finds the index of the first "on" bit.
01299        *  @return  The index of the first bit set, or size() if not found.
01300        *  @ingroup SGIextensions
01301        *  @sa  _Find_next
01302        */
01303       size_t
01304       _Find_first() const
01305       { return this->_M_do_find_first(_Nb); }
01306 
01307       /**
01308        *  @brief  Finds the index of the next "on" bit after prev.
01309        *  @return  The index of the next bit set, or size() if not found.
01310        *  @param  prev  Where to start searching.
01311        *  @ingroup SGIextensions
01312        *  @sa  _Find_first
01313        */
01314       size_t
01315       _Find_next(size_t __prev ) const
01316       { return this->_M_do_find_next(__prev, _Nb); }
01317     };
01318 
01319   // Definitions of non-inline member functions.
01320   template<size_t _Nb>
01321     template<class _CharT, class _Traits>
01322       void
01323       bitset<_Nb>::
01324       _M_copy_from_ptr(const _CharT* __s, size_t __len,
01325                size_t __pos, size_t __n, _CharT __zero, _CharT __one)
01326       {
01327     reset();
01328     const size_t __nbits = std::min(_Nb, std::min(__n, __len - __pos));
01329     for (size_t __i = __nbits; __i > 0; --__i)
01330       {
01331         const _CharT __c = __s[__pos + __nbits - __i];
01332         if (_Traits::eq(__c, __zero))
01333           ;
01334         else if (_Traits::eq(__c, __one))
01335           _Unchecked_set(__i - 1);
01336         else
01337           __throw_invalid_argument(__N("bitset::_M_copy_from_ptr"));
01338       }
01339       }
01340 
01341   template<size_t _Nb>
01342     template<class _CharT, class _Traits, class _Alloc>
01343       void
01344       bitset<_Nb>::
01345       _M_copy_to_string(std::basic_string<_CharT, _Traits, _Alloc>& __s,
01346             _CharT __zero, _CharT __one) const
01347       {
01348     __s.assign(_Nb, __zero);
01349     for (size_t __i = _Nb; __i > 0; --__i)
01350       if (_Unchecked_test(__i - 1))
01351         _Traits::assign(__s[_Nb - __i], __one);
01352       }
01353 
01354   // 23.3.5.3 bitset operations:
01355   //@{
01356   /**
01357    *  @brief  Global bitwise operations on bitsets.
01358    *  @param  x  A bitset.
01359    *  @param  y  A bitset of the same size as @a x.
01360    *  @return  A new bitset.
01361    *
01362    *  These should be self-explanatory.
01363   */
01364   template<size_t _Nb>
01365     inline bitset<_Nb>
01366     operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
01367     {
01368       bitset<_Nb> __result(__x);
01369       __result &= __y;
01370       return __result;
01371     }
01372 
01373   template<size_t _Nb>
01374     inline bitset<_Nb>
01375     operator|(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
01376     {
01377       bitset<_Nb> __result(__x);
01378       __result |= __y;
01379       return __result;
01380     }
01381 
01382   template <size_t _Nb>
01383     inline bitset<_Nb>
01384     operator^(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
01385     {
01386       bitset<_Nb> __result(__x);
01387       __result ^= __y;
01388       return __result;
01389     }
01390   //@}
01391 
01392   //@{
01393   /**
01394    *  @brief Global I/O operators for bitsets.
01395    *
01396    *  Direct I/O between streams and bitsets is supported.  Output is
01397    *  straightforward.  Input will skip whitespace, only accept @a 0 and @a 1
01398    *  characters, and will only extract as many digits as the %bitset will
01399    *  hold.
01400   */
01401   template<class _CharT, class _Traits, size_t _Nb>
01402     std::basic_istream<_CharT, _Traits>&
01403     operator>>(std::basic_istream<_CharT, _Traits>& __is, bitset<_Nb>& __x)
01404     {
01405       typedef typename _Traits::char_type          char_type;
01406       typedef std::basic_istream<_CharT, _Traits>  __istream_type;
01407       typedef typename __istream_type::ios_base    __ios_base;
01408 
01409       std::basic_string<_CharT, _Traits> __tmp;
01410       __tmp.reserve(_Nb);
01411 
01412       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01413       // 303. Bitset input operator underspecified
01414       const char_type __zero = __is.widen('0');
01415       const char_type __one = __is.widen('1');
01416 
01417       typename __ios_base::iostate __state = __ios_base::goodbit;
01418       typename __istream_type::sentry __sentry(__is);
01419       if (__sentry)
01420     {
01421       __try
01422         {
01423           for (size_t __i = _Nb; __i > 0; --__i)
01424         {
01425           static typename _Traits::int_type __eof = _Traits::eof();
01426           
01427           typename _Traits::int_type __c1 = __is.rdbuf()->sbumpc();
01428           if (_Traits::eq_int_type(__c1, __eof))
01429             {
01430               __state |= __ios_base::eofbit;
01431               break;
01432             }
01433           else
01434             {
01435               const char_type __c2 = _Traits::to_char_type(__c1);
01436               if (_Traits::eq(__c2, __zero))
01437             __tmp.push_back(__zero);
01438               else if (_Traits::eq(__c2, __one))
01439             __tmp.push_back(__one);
01440               else if (_Traits::
01441                    eq_int_type(__is.rdbuf()->sputbackc(__c2),
01442                        __eof))
01443             {
01444               __state |= __ios_base::failbit;
01445               break;
01446             }
01447             }
01448         }
01449         }
01450       __catch(__cxxabiv1::__forced_unwind&)
01451         {
01452           __is._M_setstate(__ios_base::badbit);     
01453           __throw_exception_again;
01454         }
01455       __catch(...)
01456         { __is._M_setstate(__ios_base::badbit); }
01457     }
01458 
01459       if (__tmp.empty() && _Nb)
01460     __state |= __ios_base::failbit;
01461       else
01462     __x._M_copy_from_string(__tmp, static_cast<size_t>(0), _Nb,
01463                 __zero, __one);
01464       if (__state)
01465     __is.setstate(__state);
01466       return __is;
01467     }
01468 
01469   template <class _CharT, class _Traits, size_t _Nb>
01470     std::basic_ostream<_CharT, _Traits>&
01471     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
01472            const bitset<_Nb>& __x)
01473     {
01474       std::basic_string<_CharT, _Traits> __tmp;
01475 
01476       // _GLIBCXX_RESOLVE_LIB_DEFECTS
01477       // 396. what are characters zero and one.
01478       const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__os.getloc());
01479       __x._M_copy_to_string(__tmp, __ct.widen('0'), __ct.widen('1'));
01480       return __os << __tmp;
01481     }
01482   //@}
01483 
01484 _GLIBCXX_END_NESTED_NAMESPACE
01485 
01486 #undef _GLIBCXX_BITSET_WORDS
01487 #undef _GLIBCXX_BITSET_BITS_PER_WORD
01488 
01489 #ifdef __GXX_EXPERIMENTAL_CXX0X__
01490 
01491 #include <bits/functional_hash.h>
01492 
01493 _GLIBCXX_BEGIN_NAMESPACE(std)
01494 
01495   // DR 1182.
01496   /// std::hash specialization for bitset.
01497   template<size_t _Nb>
01498     struct hash<_GLIBCXX_STD_D::bitset<_Nb>>
01499     : public std::unary_function<_GLIBCXX_STD_D::bitset<_Nb>, size_t>
01500     {
01501       size_t
01502       operator()(const _GLIBCXX_STD_D::bitset<_Nb>& __b) const
01503       {
01504     const size_t __clength = (_Nb + __CHAR_BIT__ - 1) / __CHAR_BIT__;
01505     return std::_Fnv_hash::hash(__b._M_getdata(), __clength);
01506       }
01507     };
01508 
01509   template<>
01510     struct hash<_GLIBCXX_STD_D::bitset<0>>
01511     : public std::unary_function<_GLIBCXX_STD_D::bitset<0>, size_t>
01512     {
01513       size_t
01514       operator()(const _GLIBCXX_STD_D::bitset<0>&) const
01515       { return 0; }
01516     };
01517 
01518 _GLIBCXX_END_NAMESPACE
01519 
01520 #endif // __GXX_EXPERIMENTAL_CXX0X__
01521 
01522 #ifdef _GLIBCXX_DEBUG
01523 # include <debug/bitset>
01524 #endif
01525 
01526 #ifdef _GLIBCXX_PROFILE
01527 # include <profile/bitset>
01528 #endif
01529 
01530 #endif /* _GLIBCXX_BITSET */