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Whole document tree                   std_bitset.h Go to the documentation of this file. // <bitset> -*- C++ -*- // Copyright (C) 2001 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. */ #ifndef __SGI_STL_BITSET #define __SGI_STL_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. // The C++ standard does not define the precise semantics of operator[]. // In this implementation the const version of operator[] is equivalent // to test(), except that it does no range checking. The non-const version // returns a reference to a bit, again without doing any range checking. #include <bits/std_cstddef.h> // for size_t #include <bits/std_cstring.h> // for memset #include <bits/std_string.h> #include <bits/std_stdexcept.h> // for invalid_argument, out_of_range, // overflow_error #include <bits/std_ostream.h> // for ostream (operator<<) #include <bits/std_istream.h> // 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 { // structure to aid in counting bits template<bool __dummy> struct _Bit_count { static unsigned char _S_bit_count[256]; }; // Mapping from 8 bit unsigned integers to the index of the first one // bit: template<bool __dummy> struct _First_one { static unsigned char _S_first_one[256]; }; // // Base class: general case. // template<size_t _Nw> struct _Base_bitset { typedef unsigned long _WordT; _WordT _M_w[_Nw]; // 0 is the least significant word. _Base_bitset( void ) { _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 += _Bit_count<true>::_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]) __STL_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 + _First_one<true>::_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 + _First_one<true>::_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 + _First_one<true>::_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 += _Bit_count<true>::_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 _M_do_sanitize(unsigned long& __val) { __val &= ~((~static_cast<unsigned long>(0)) << _Extrabits); } }; template<> struct _Sanitize<0> { static void _M_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; private: void _M_do_sanitize() { _Sanitize<_Nb%_GLIBCPP_BITSET_BITS_PER_WORD>::_M_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()) __STL_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()) __STL_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) __STL_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) __STL_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) __STL_THROW(out_of_range("bitset")); return _Unchecked_flip(__pos); } bitset<_Nb> operator~() const { return bitset<_Nb>(*this).flip(); } // element access: //for b[i]; 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) __STL_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: __STL_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 /* __SGI_STL_BITSET */ // Local Variables: // mode:C++ // End: