* 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
+#ifndef _GLIBCPP_BITSET_H
+#define _GLIBCPP_BITSET_H
#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 <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) \
+#define _GLIBCPP_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.
+ /**
+ * @if maint
+ * Base class, general case. It is a class inveriant that _Nw will be
+ * nonnegative.
+ *
+ * See documentation for bitset.
+ * @endif
+ */
template<size_t _Nw>
- struct _Base_bitset
+ struct _Base_bitset
{
typedef unsigned long _WordT;
- // 0 is the least significant word.
- _WordT _M_w[_Nw];
-
+ /// 0 is the least significant word.
+ _WordT _M_w[_Nw];
+
_Base_bitset() { _M_do_reset(); }
- _Base_bitset(unsigned long __val)
+ _Base_bitset(unsigned long __val)
{
_M_do_reset();
_M_w[0] = __val;
}
- static size_t
+ static size_t
_S_whichword(size_t __pos )
{ return __pos / _GLIBCPP_BITSET_BITS_PER_WORD; }
- static size_t
+ static size_t
_S_whichbyte(size_t __pos )
{ return (__pos % _GLIBCPP_BITSET_BITS_PER_WORD) / CHAR_BIT; }
- static size_t
+ static size_t
_S_whichbit(size_t __pos )
{ return __pos % _GLIBCPP_BITSET_BITS_PER_WORD; }
- static _WordT
+ static _WordT
_S_maskbit(size_t __pos )
{ return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
- _WordT&
- _M_getword(size_t __pos)
+ _WordT&
+ _M_getword(size_t __pos)
{ return _M_w[_S_whichword(__pos)]; }
- _WordT
- _M_getword(size_t __pos) const
+ _WordT
+ _M_getword(size_t __pos) const
{ return _M_w[_S_whichword(__pos)]; }
- _WordT&
+ _WordT&
_M_hiword() { return _M_w[_Nw - 1]; }
- _WordT
+ _WordT
_M_hiword() const { return _M_w[_Nw - 1]; }
- void
- _M_do_and(const _Base_bitset<_Nw>& __x)
+ void
+ _M_do_and(const _Base_bitset<_Nw>& __x)
{
- for (size_t __i = 0; __i < _Nw; __i++)
+ for (size_t __i = 0; __i < _Nw; __i++)
_M_w[__i] &= __x._M_w[__i];
}
- void
- _M_do_or(const _Base_bitset<_Nw>& __x)
+ void
+ _M_do_or(const _Base_bitset<_Nw>& __x)
{
- for (size_t __i = 0; __i < _Nw; __i++)
+ for (size_t __i = 0; __i < _Nw; __i++)
_M_w[__i] |= __x._M_w[__i];
}
- void
- _M_do_xor(const _Base_bitset<_Nw>& __x)
+ 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
+ void
_M_do_left_shift(size_t __shift);
- void
+ void
_M_do_right_shift(size_t __shift);
-
- void
- _M_do_flip()
+
+ void
+ _M_do_flip()
{
- for (size_t __i = 0; __i < _Nw; __i++)
+ for (size_t __i = 0; __i < _Nw; __i++)
_M_w[__i] = ~_M_w[__i];
}
- void
- _M_do_set()
+ void
+ _M_do_set()
{
for (size_t __i = 0; __i < _Nw; __i++)
_M_w[__i] = ~static_cast<_WordT>(0);
}
- void
+ void
_M_do_reset() { memset(_M_w, 0, _Nw * sizeof(_WordT)); }
- bool
- _M_is_equal(const _Base_bitset<_Nw>& __x) const
+ bool
+ _M_is_equal(const _Base_bitset<_Nw>& __x) const
{
- for (size_t __i = 0; __i < _Nw; ++__i)
+ 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
+ bool
+ _M_is_any() const
{
- for (size_t __i = 0; __i < _Nw; __i++)
+ 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
+ _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 )
+
+ while ( __byte_ptr < __end_ptr )
{
__result += _S_bit_count[*__byte_ptr];
__byte_ptr++;
return __result;
}
- unsigned long
- _M_do_to_ulong() const;
+ unsigned long
+ _M_do_to_ulong() const;
// find first "on" bit
- size_t
+ size_t
_M_do_find_first(size_t __not_found) const;
// find the next "on" bit that follows "prev"
- size_t
+ 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)
+ void
+ _Base_bitset<_Nw>::_M_do_left_shift(size_t __shift)
{
- if (__shift != 0)
+ 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
+ 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] = (_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)
+ void
+ _Base_bitset<_Nw>::_M_do_right_shift(size_t __shift)
{
- if (__shift != 0)
+ 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
+ else
{
const size_t __sub_offset = _GLIBCPP_BITSET_BITS_PER_WORD - __offset;
for (size_t __n = 0; __n < __limit; ++__n)
(_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
+ 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");
+ for (size_t __i = 1; __i < _Nw; ++__i)
+ if (_M_w[__i])
+ __throw_overflow_error("bitset -- too large to fit in unsigned long");
return _M_w[0];
}
template<size_t _Nw>
- size_t
- _Base_bitset<_Nw>::_M_do_find_first(size_t __not_found) const
+ size_t
+ _Base_bitset<_Nw>::_M_do_find_first(size_t __not_found) const
{
- for (size_t __i = 0; __i < _Nw; __i++ )
+ for (size_t __i = 0; __i < _Nw; __i++ )
{
_WordT __thisword = _M_w[__i];
- if ( __thisword != static_cast<_WordT>(0) )
+ if ( __thisword != static_cast<_WordT>(0) )
{
// find byte within word
- for (size_t __j = 0; __j < sizeof(_WordT); __j++ )
+ for (size_t __j = 0; __j < sizeof(_WordT); __j++ )
{
unsigned char __this_byte
= static_cast<unsigned char>(__thisword & (~(unsigned char)0));
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) )
+
+ if ( __thisword != static_cast<_WordT>(0) )
{
// find byte within word
// get first byte into place
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++ )
+ for ( ; __i < _Nw; __i++ )
{
__thisword = _M_w[__i];
- if ( __thisword != static_cast<_WordT>(0) )
+ if ( __thisword != static_cast<_WordT>(0) )
{
// find byte within word
- for (size_t __j = 0; __j < sizeof(_WordT); __j++ )
+ 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>
+
+ /**
+ * @if maint
+ * Base class, specialization for a single word.
+ *
+ * See documentation for bitset.
+ * @endif
+ */
+ 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
+ static size_t
_S_whichword(size_t __pos )
{ return __pos / _GLIBCPP_BITSET_BITS_PER_WORD; }
- static size_t
+ static size_t
_S_whichbyte(size_t __pos )
{ return (__pos % _GLIBCPP_BITSET_BITS_PER_WORD) / CHAR_BIT; }
- static size_t
+ static size_t
_S_whichbit(size_t __pos )
{ return __pos % _GLIBCPP_BITSET_BITS_PER_WORD; }
- static _WordT
+ static _WordT
_S_maskbit(size_t __pos )
{ return (static_cast<_WordT>(1)) << _S_whichbit(__pos); }
- _WordT&
+ _WordT&
_M_getword(size_t) { return _M_w; }
- _WordT
+ _WordT
_M_getword(size_t) const { return _M_w; }
- _WordT&
+ _WordT&
_M_hiword() { return _M_w; }
- _WordT
+ _WordT
_M_hiword() const { return _M_w; }
- void
+ void
_M_do_and(const _Base_bitset<1>& __x) { _M_w &= __x._M_w; }
- void
+ void
_M_do_or(const _Base_bitset<1>& __x) { _M_w |= __x._M_w; }
- void
+ void
_M_do_xor(const _Base_bitset<1>& __x) { _M_w ^= __x._M_w; }
- void
+ void
_M_do_left_shift(size_t __shift) { _M_w <<= __shift; }
- void
+ void
_M_do_right_shift(size_t __shift) { _M_w >>= __shift; }
- void
+ void
_M_do_flip() { _M_w = ~_M_w; }
- void
+ void
_M_do_set() { _M_w = ~static_cast<_WordT>(0); }
- void
+ void
_M_do_reset() { _M_w = 0; }
- bool
+ bool
_M_is_equal(const _Base_bitset<1>& __x) const
{ return _M_w == __x._M_w; }
- bool
+ bool
_M_is_any() const { return _M_w != 0; }
- size_t
- _M_do_count() const
+ 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 )
+ while ( __byte_ptr < __end_ptr )
{
__result += _S_bit_count[*__byte_ptr];
__byte_ptr++;
return __result;
}
- unsigned long
+ unsigned long
_M_do_to_ulong() const { return _M_w; }
- size_t
+ 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;
+ _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
+ 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>
+ template<>
+ struct _Sanitize<0>
{ static void _S_do_sanitize(unsigned long) { } };
- // Class bitset.
- // _Nb may be any nonzero number of type size_t.
+ /**
+ * @brief The %bitset class represents a @e fixed-size sequence of bits.
+ *
+ * @ingroup Containers
+ *
+ * Meets the requirements of a <a href="tables.html#65">container</a>.
+ *
+ * The template argument, @a _Nb, may be any nonzero number of type
+ * size_t.
+ *
+ * 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 that those unused bits are always zero.
+ *
+ * If you think of %bitset as "a simple array of bits," be aware that
+ * your mental picture is reversed: a %bitset behaves the same way as
+ * bits in integers do, with the bit at index 0 in the "least significant
+ * / right-hand" position, and the bit at index N-1 in the "most
+ * significant / left-hand" position. Thus, unlike other containers, a
+ * %bitset's index "counts from right to left," to put it very loosely.
+ *
+ * This behavior is preserved when translating to and from strings. For
+ * example, the first line of the following program probably prints
+ * "b('a') is 0001100001" on a modern ASCII system.
+ *
+ * @code
+ * #include <bitset>
+ * #include <iostream>
+ * #include <sstream>
+ *
+ * using namespace std;
+ *
+ * int main()
+ * {
+ * long a = 'a';
+ * bitset<10> b(a);
+ *
+ * cout << "b('a') is " << b << endl;
+ *
+ * ostringstream s;
+ * s << b;
+ * string str = s.str();
+ * cout << "index 3 in the string is " << str[3] << " but\n"
+ * << "index 3 in the bitset is " << b[3] << endl;
+ * }
+ * @endcode
+ *
+ * Also see http://gcc.gnu.org/onlinedocs/libstdc++/ext/sgiexts.html#ch23
+ *
+ * @if maint
+ * 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.
+ *
+ * Extra confusion can result due to the fact that the storage for
+ * _Base_bitset @e is a regular array, and is indexed as such. This is
+ * carefully encapsulated.
+ * @endif
+ */
template<size_t _Nb>
- class bitset : private _Base_bitset<__BITSET_WORDS(_Nb)>
+ class bitset : private _Base_bitset<_GLIBCPP_BITSET_WORDS(_Nb)>
{
private:
- typedef _Base_bitset<__BITSET_WORDS(_Nb)> _Base;
+ typedef _Base_bitset<_GLIBCPP_BITSET_WORDS(_Nb)> _Base;
typedef unsigned long _WordT;
-
- void
- _M_do_sanitize()
+
+ void
+ _M_do_sanitize()
{
- _Sanitize<_Nb%_GLIBCPP_BITSET_BITS_PER_WORD>::_S_do_sanitize(this->_M_hiword());
+ _Sanitize<_Nb%_GLIBCPP_BITSET_BITS_PER_WORD>::
+ _S_do_sanitize(this->_M_hiword());
}
public:
- // bit reference:
- class reference;
- friend class reference;
-
- class reference
+ /**
+ * This encapsulates the concept of a single bit. An instance of this
+ * class is a proxy for an actual bit; this way the individual bit
+ * operations are done as faster word-size bitwise instructions.
+ *
+ * Most users will never need to use this class directly; conversions
+ * to and from bool are automatic and should be transparent. Overloaded
+ * operators help to preserve the illusion.
+ *
+ * (On a typical system, this "bit %reference" is 64 times the size of
+ * an actual bit. Ha.)
+ */
+ class reference
{
friend class bitset;
-
+
_WordT *_M_wp;
size_t _M_bpos;
-
+
// left undefined
reference();
-
+
public:
- reference( bitset& __b, size_t __pos )
+ 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)
+ reference&
+ operator=(bool __x)
{
if ( __x )
*_M_wp |= _Base::_S_maskbit(_M_bpos);
*_M_wp &= ~_Base::_S_maskbit(_M_bpos);
return *this;
}
-
+
// for b[i] = b[__j];
- reference&
- operator=(const reference& __j)
+ reference&
+ operator=(const reference& __j)
{
if ( (*(__j._M_wp) & _Base::_S_maskbit(__j._M_bpos)) )
*_M_wp |= _Base::_S_maskbit(_M_bpos);
}
// flips the bit
- bool
+ bool
operator~() const
{ return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) == 0; }
{ return (*(_M_wp) & _Base::_S_maskbit(_M_bpos)) != 0; }
// for b[i].flip();
- reference&
- flip()
+ reference&
+ flip()
{
*_M_wp ^= _Base::_S_maskbit(_M_bpos);
return *this;
}
};
-
+ friend class reference;
+
// 23.3.5.1 constructors:
+ /// All bits set to zero.
bitset() { }
- bitset(unsigned long __val) : _Base_bitset<__BITSET_WORDS(_Nb)>(__val)
+ /// Initial bits bitwise-copied from a single word (others set to zero).
+ bitset(unsigned long __val) : _Base(__val)
{ _M_do_sanitize(); }
+ /**
+ * @brief Use a subset of a string.
+ * @param s A string of '0' and '1' characters.
+ * @param pos Index of the first character in @a s to use; defaults
+ * to zero.
+ * @throw std::out_of_range If @a pos is bigger the size of @a s.
+ * @throw std::invalid_argument If a character appears in the string
+ * which is neither '0' nor '1'.
+ */
template<class _CharT, class _Traits, class _Alloc>
explicit bitset(const basic_string<_CharT, _Traits, _Alloc>& __s,
- size_t __pos = 0) : _Base()
+ size_t __pos = 0) : _Base()
{
- if (__pos > __s.size())
- __throw_out_of_range("bitset");
+ if (__pos > __s.size())
+ __throw_out_of_range("bitset -- initial position is larger than "
+ "the string itself");
_M_copy_from_string(__s, __pos,
basic_string<_CharT, _Traits, _Alloc>::npos);
}
+ /**
+ * @brief Use a subset of a string.
+ * @param s A string of '0' and '1' characters.
+ * @param pos Index of the first character in @a s to use.
+ * @param n The number of characters to copy.
+ * @throw std::out_of_range If @a pos is bigger the size of @a s.
+ * @throw std::invalid_argument If a character appears in the string
+ * which is neither '0' nor '1'.
+ */
template<class _CharT, class _Traits, class _Alloc>
bitset(const basic_string<_CharT, _Traits, _Alloc>& __s,
- size_t __pos, size_t __n) : _Base()
+ size_t __pos, size_t __n) : _Base()
{
- if (__pos > __s.size())
- __throw_out_of_range("bitset");
+ if (__pos > __s.size())
+ __throw_out_of_range("bitset -- initial position is larger than "
+ "the string itself");
_M_copy_from_string(__s, __pos, __n);
}
// 23.3.5.2 bitset operations:
- bitset<_Nb>&
- operator&=(const bitset<_Nb>& __rhs)
+ //@{
+ /**
+ * @brief Operations on bitsets.
+ * @param rhs A same-sized bitset.
+ *
+ * These should be self-explanatory.
+ */
+ bitset<_Nb>&
+ operator&=(const bitset<_Nb>& __rhs)
{
this->_M_do_and(__rhs);
return *this;
}
- bitset<_Nb>&
- operator|=(const bitset<_Nb>& __rhs)
+ bitset<_Nb>&
+ operator|=(const bitset<_Nb>& __rhs)
{
this->_M_do_or(__rhs);
return *this;
}
- bitset<_Nb>&
- operator^=(const bitset<_Nb>& __rhs)
+ bitset<_Nb>&
+ operator^=(const bitset<_Nb>& __rhs)
{
this->_M_do_xor(__rhs);
return *this;
}
-
- bitset<_Nb>&
- operator<<=(size_t __pos)
+ //@}
+
+ //@{
+ /**
+ * @brief Operations on bitsets.
+ * @param pos The number of places to shift.
+ *
+ * These should be self-explanatory.
+ */
+ bitset<_Nb>&
+ operator<<=(size_t __pos)
{
this->_M_do_left_shift(__pos);
this->_M_do_sanitize();
return *this;
}
- bitset<_Nb>&
- operator>>=(size_t __pos)
+ 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)
+ //@}
+
+ //@{
+ /**
+ * These versions of single-bit set, reset, flip, and test are
+ * extensions from the SGI version. They do no range checking.
+ * @ingroup SGIextensions
+ */
+ 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)
+ bitset<_Nb>&
+ _Unchecked_set(size_t __pos, int __val)
{
if (__val)
this->_M_getword(__pos) |= _Base::_S_maskbit(__pos);
return *this;
}
- bitset<_Nb>&
- _Unchecked_reset(size_t __pos)
+ bitset<_Nb>&
+ _Unchecked_reset(size_t __pos)
{
this->_M_getword(__pos) &= ~_Base::_S_maskbit(__pos);
return *this;
}
- bitset<_Nb>&
- _Unchecked_flip(size_t __pos)
+ bitset<_Nb>&
+ _Unchecked_flip(size_t __pos)
{
this->_M_getword(__pos) ^= _Base::_S_maskbit(__pos);
return *this;
}
- bool
- _Unchecked_test(size_t __pos) const
+ bool
+ _Unchecked_test(size_t __pos) const
{
- return (this->_M_getword(__pos) & _Base::_S_maskbit(__pos))
+ return (this->_M_getword(__pos) & _Base::_S_maskbit(__pos))
!= static_cast<_WordT>(0);
}
+ //@}
// Set, reset, and flip.
- bitset<_Nb>&
- set()
+ /**
+ * @brief Sets every bit to true.
+ */
+ bitset<_Nb>&
+ set()
{
this->_M_do_set();
this->_M_do_sanitize();
return *this;
}
- bitset<_Nb>&
- set(size_t __pos, bool __val = true)
+ /**
+ * @brief Sets a given bit to a particular value.
+ * @param pos The index of the bit.
+ * @param val Either true or false, defaults to true.
+ * @throw std::out_of_range If @a pos is bigger the size of the %set.
+ */
+ bitset<_Nb>&
+ set(size_t __pos, bool __val = true)
{
if (__pos >= _Nb)
- __throw_out_of_range("bitset");
+ __throw_out_of_range("bitset -- set() argument too large");
return _Unchecked_set(__pos, __val);
}
- bitset<_Nb>&
- reset()
+ /**
+ * @brief Sets every bit to false.
+ */
+ bitset<_Nb>&
+ reset()
{
this->_M_do_reset();
return *this;
}
- bitset<_Nb>&
- reset(size_t __pos)
+ /**
+ * @brief Sets a given bit to false.
+ * @param pos The index of the bit.
+ * @throw std::out_of_range If @a pos is bigger the size of the %set.
+ *
+ * Same as writing @c set(pos,false).
+ */
+ bitset<_Nb>&
+ reset(size_t __pos)
{
if (__pos >= _Nb)
- __throw_out_of_range("bitset");
+ __throw_out_of_range("bitset -- reset() argument too large");
return _Unchecked_reset(__pos);
}
- bitset<_Nb>&
- flip()
+ /**
+ * @brief Toggles every bit to its opposite value.
+ */
+ bitset<_Nb>&
+ flip()
{
this->_M_do_flip();
this->_M_do_sanitize();
return *this;
}
- bitset<_Nb>&
- flip(size_t __pos)
+ /**
+ * @brief Toggles a given bit to its opposite value.
+ * @param pos The index of the bit.
+ * @throw std::out_of_range If @a pos is bigger the size of the %set.
+ */
+ bitset<_Nb>&
+ flip(size_t __pos)
{
if (__pos >= _Nb)
- __throw_out_of_range("bitset");
+ __throw_out_of_range("bitset -- flip() argument too large");
return _Unchecked_flip(__pos);
}
- bitset<_Nb>
+ /// See the no-argument flip().
+ 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
+ //@{
+ /**
+ * @brief Array-indexing support.
+ * @param pos Index into the %bitset.
+ * @return A bool for a 'const %bitset'. For non-const bitsets, an
+ * instance of the reference proxy class.
+ * @note These operators do no range checking and throw no exceptions,
+ * as required by DR 11 to the standard.
+ *
+ * @if maint
+ * _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
+ * The DR has since been changed: range-checking is a precondition
+ * (users' responsibility), and these functions must not throw. -pme
+ * @endif
+ */
+ reference
operator[](size_t __pos) { return reference(*this,__pos); }
- bool
+ bool
operator[](size_t __pos) const { return _Unchecked_test(__pos); }
-
- unsigned long
+ //@}
+
+ /**
+ * @brief Retuns a numerical interpretation of the %bitset.
+ * @return The integral equivalent of the bits.
+ * @throw std::overflow_error If there are too many bits to be
+ * represented in an @c unsigned @c long.
+ */
+ unsigned long
to_ulong() const { return this->_M_do_to_ulong(); }
+ /**
+ * @brief Retuns a character interpretation of the %bitset.
+ * @return The string equivalent of the bits.
+ *
+ * Note the ordering of the bits: decreasing character positions
+ * correspond to increasing bit positions (see the main class notes for
+ * an example).
+ *
+ * Also note that you must specify the string's template parameters
+ * explicitly. Given a bitset @c bs and a string @s:
+ * @code
+ * s = bs.to_string<char,char_traits<char>,allocator<char> >();
+ * @endcode
+ */
template<class _CharT, class _Traits, class _Alloc>
- basic_string<_CharT, _Traits, _Alloc>
- to_string() const
+ basic_string<_CharT, _Traits, _Alloc>
+ to_string() const
{
basic_string<_CharT, _Traits, _Alloc> __result;
_M_copy_to_string(__result);
// Helper functions for string operations.
template<class _CharT, class _Traits, class _Alloc>
- void
+ void
_M_copy_from_string(const basic_string<_CharT,_Traits,_Alloc>& __s,
size_t, size_t);
template<class _CharT, class _Traits, class _Alloc>
- void
+ void
_M_copy_to_string(basic_string<_CharT,_Traits,_Alloc>&) const;
- size_t
+ /// Returns the number of bits which are set.
+ size_t
count() const { return this->_M_do_count(); }
- size_t
+ /// Returns the total number of bits.
+ size_t
size() const { return _Nb; }
- bool
- operator==(const bitset<_Nb>& __rhs) const
+ //@{
+ /// These comparisons for equality/inequality are, well, @e bitwise.
+ bool
+ operator==(const bitset<_Nb>& __rhs) const
{ return this->_M_is_equal(__rhs); }
- bool
- operator!=(const bitset<_Nb>& __rhs) const
+ bool
+ operator!=(const bitset<_Nb>& __rhs) const
{ return !this->_M_is_equal(__rhs); }
-
- bool
- test(size_t __pos) const
+ //@}
+
+ /**
+ * @brief Tests the value of a bit.
+ * @param pos The index of a bit.
+ * @return The value at @a pos.
+ * @throw std::out_of_range If @a pos is bigger the size of the %set.
+ */
+ bool
+ test(size_t __pos) const
{
if (__pos >= _Nb)
- __throw_out_of_range("bitset");
+ __throw_out_of_range("bitset -- test() argument too large");
return _Unchecked_test(__pos);
}
- bool
+ /**
+ * @brief Tests whether any of the bits are on.
+ * @return True if at least one bit is set.
+ */
+ bool
any() const { return this->_M_is_any(); }
- bool
+ /**
+ * @brief Tests whether any of the bits are on.
+ * @return True if none of the bits are set.
+ */
+ bool
none() const { return !this->_M_is_any(); }
- bitset<_Nb>
+ //@{
+ /// Self-explanatory.
+ bitset<_Nb>
operator<<(size_t __pos) const
{ return bitset<_Nb>(*this) <<= __pos; }
- bitset<_Nb>
+ 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
+ /**
+ * @brief Finds the index of the first "on" bit.
+ * @ingroup SGIextensions
+ * @sa _Find_next
+ */
+ 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
+ /**
+ * @brief Finds the index of the next "on" bit after prev.
+ * @param prev Where to start searching.
+ * @ingroup SGIextensions
+ * @sa _Find_first
+ */
+ 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
+ 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)
+ for (size_t __i = 0; __i < __nbits; ++__i)
{
- switch(__s[__pos + __nbits - __i - 1])
+ switch(__s[__pos + __nbits - __i - 1])
{
case '0':
break;
set(__i);
break;
default:
- __throw_invalid_argument("bitset");
+ __throw_invalid_argument("bitset -- string contains characters "
+ "which are neither 0 nor 1");
}
}
}
template<size_t _Nb>
template<class _CharT, class _Traits, class _Alloc>
- void
+ 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)
+ for (size_t __i = 0; __i < _Nb; ++__i)
if (_Unchecked_test(__i))
__s[_Nb - 1 - __i] = '1';
}
// 23.3.5.3 bitset operations:
+ //@{
+ /**
+ * @brief Global bitwise operations on bitsets.
+ * @param x A bitset.
+ * @param y A bitset of the same size as @a x.
+ * @return A new bitset.
+ *
+ * These should be self-explanatory.
+ */
template<size_t _Nb>
- inline bitset<_Nb>
- operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
+ inline bitset<_Nb>
+ operator&(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
{
bitset<_Nb> __result(__x);
__result &= __y;
}
template<size_t _Nb>
- inline bitset<_Nb>
- operator|(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
+ inline bitset<_Nb>
+ operator|(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
{
bitset<_Nb> __result(__x);
__result |= __y;
}
template <size_t _Nb>
- inline bitset<_Nb>
- operator^(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
+ inline bitset<_Nb>
+ operator^(const bitset<_Nb>& __x, const bitset<_Nb>& __y)
{
bitset<_Nb> __result(__x);
__result ^= __y;
return __result;
}
-
+ //@}
+
+ //@{
+ /**
+ * @brief Global I/O operators for bitsets.
+ *
+ * Direct I/O between streams and bitsets is supported. Output is
+ * straightforward. Input will skip whitespace, only accept '0' and '1'
+ * characters, and will only extract as many digits as the %bitset will
+ * hold.
+ */
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)
+ if (__sentry)
{
basic_streambuf<_CharT, _Traits>* __buf = __is.rdbuf();
- for (size_t __i = 0; __i < _Nb; ++__i)
+ 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))
+ if (_Traits::eq_int_type(__c1, __eof))
{
__is.setstate(ios_base::eofbit);
break;
}
- else
+ 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))
+ 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_to_string(__tmp);
return __os << __tmp;
}
+ //@}
} // namespace std
-#undef __BITSET_WORDS
+#undef _GLIBCPP_BITSET_WORDS
-#endif
+#endif /* _GLIBCPP_BITSET_H */
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