std::tr2::dynamic_bitset - Man Page

class reference

typedef __dynamic_bitset_base< _WordT, _Alloc > _Base
typedef _Alloc allocator_type
typedef _WordT block_type
typedef bool const_reference
typedef size_t size_type

dynamic_bitset ()=default
All bits set to zero.
dynamic_bitset (const allocator_type &__alloc)
All bits set to zero.
dynamic_bitset (const char *__str, const allocator_type &__alloc=allocator_type())
Construct from a string.
dynamic_bitset (const dynamic_bitset &)=default
Copy constructor.
template<typename _CharT , typename _Traits , typename _Alloc1 > dynamic_bitset (const std::basic_string< _CharT, _Traits, _Alloc1 > &__str, typename basic_string< _CharT, _Traits, _Alloc1 >::size_type __pos=0, typename basic_string< _CharT, _Traits, _Alloc1 >::size_type __n=std::basic_string< _CharT, _Traits, _Alloc1 >::npos, _CharT __zero=_CharT('0'), _CharT __one=_CharT('1'), const allocator_type &__alloc=allocator_type())
Use a subset of a string.
dynamic_bitset (dynamic_bitset &&__b) noexcept
Move constructor.
dynamic_bitset (initializer_list< block_type > __il, const allocator_type &__alloc=allocator_type())
dynamic_bitset (size_type __nbits, unsigned long long __val=0ULL, const allocator_type &__alloc=allocator_type())
Initial bits bitwise-copied from a single word (others set to zero).
template<typename _Traits  = std::char_traits<char>, typename _CharT  = typename _Traits::char_type> void _M_copy_from_ptr (const _CharT *, size_t, size_t, size_t, _CharT __zero=_CharT('0'), _CharT __one=_CharT('1'))
template<typename _CharT , typename _Traits , typename _Alloc1 > void _M_copy_from_string (const basic_string< _CharT, _Traits, _Alloc1 > &__str, size_t __pos, size_t __n, _CharT __zero=_CharT('0'), _CharT __one=_CharT('1'))
template<typename _CharT , typename _Traits , typename _Alloc1 > void _M_copy_to_string (std::basic_string< _CharT, _Traits, _Alloc1 > &__str, _CharT __zero=_CharT('0'), _CharT __one=_CharT('1')) const
bool all () const
Tests whether all the bits are on.
bool any () const
Tests whether any of the bits are on.
template<typename _BlockInputIterator > void append (_BlockInputIterator __first, _BlockInputIterator __last)
Append an iterator range of blocks.
void append (block_type __block)
Append a block.
void append (initializer_list< block_type > __il)
void clear ()
Clear the bitset.
size_type count () const noexcept
Returns the number of bits which are set.
bool empty () const noexcept
Returns true if the dynamic_bitset is empty.
size_type find_first () const
Finds the index of the first 'on' bit.
size_type find_next (size_t __prev) const
Finds the index of the next 'on' bit after prev.
dynamic_bitset & flip ()
Toggles every bit to its opposite value.
dynamic_bitset & flip (size_type __pos)
Toggles a given bit to its opposite value.
allocator_type get_allocator () const noexcept
Return the allocator for the bitset.
bool is_proper_subset_of (const dynamic_bitset &__b) const
bool is_subset_of (const dynamic_bitset &__b) const
constexpr size_type max_size () noexcept
Returns the maximum size of a dynamic_bitset object having the same type as *this. The real answer is max() * bits_per_block but is likely to overflow.
bool none () const
Tests whether any of the bits are on.
size_type num_blocks () const noexcept
Returns the total number of blocks.
dynamic_bitset & operator= (const dynamic_bitset &)=default
Copy assignment operator.
dynamic_bitset & operator= (dynamic_bitset &&__b) noexcept(std::is_nothrow_move_assignable< _Base >::value)
Move assignment operator.
dynamic_bitset operator~ () const
See the no-argument flip().
void push_back (bool __bit)
Push a bit onto the high end of the bitset.
dynamic_bitset & reset ()
Sets every bit to false.
dynamic_bitset & reset (size_type __pos)
Sets a given bit to false.
void resize (size_type __nbits, bool __value=false)
Resize the bitset.
dynamic_bitset & set ()
Sets every bit to true.
dynamic_bitset & set (size_type __pos, bool __val=true)
Sets a given bit to a particular value.
size_type size () const noexcept
Returns the total number of bits.
void swap (dynamic_bitset &__b) noexcept
Swap with another bitset.
bool test (size_type __pos) const
Tests the value of a bit.
template<typename _CharT  = char, typename _Traits  = std::char_traits<_CharT>, typename _Alloc1  = std::allocator<_CharT>> std::basic_string< _CharT, _Traits, _Alloc1 > to_string (_CharT __zero=_CharT('0'), _CharT __one=_CharT('1')) const
Returns a character interpretation of the dynamic_bitset.
unsigned long long to_ullong () const
Returns a numerical interpretation of the dynamic_bitset.
unsigned long to_ulong () const
Returns a numerical interpretation of the dynamic_bitset.

dynamic_bitset & operator&= (const dynamic_bitset &__rhs)
Operations on dynamic_bitsets.
dynamic_bitset & operator&= (dynamic_bitset &&__rhs)
Operations on dynamic_bitsets.
dynamic_bitset & operator|= (const dynamic_bitset &__rhs)
Operations on dynamic_bitsets.
dynamic_bitset & operator^= (const dynamic_bitset &__rhs)
Operations on dynamic_bitsets.
dynamic_bitset & operator-= (const dynamic_bitset &__rhs)
Operations on dynamic_bitsets.

dynamic_bitset & operator<<= (size_type __pos)
Operations on dynamic_bitsets.
dynamic_bitset & operator>>= (size_type __pos)
Operations on dynamic_bitsets.

reference operator[] (size_type __pos)
Array-indexing support.
const_reference operator[] (size_type __pos) const
Array-indexing support.

dynamic_bitset operator<< (size_type __pos) const
Self-explanatory.
dynamic_bitset operator>> (size_type __pos) const
Self-explanatory.

static const size_type bits_per_block
static const size_type npos

bool operator< (const dynamic_bitset &__lhs, const dynamic_bitset &__rhs) noexcept
bool operator== (const dynamic_bitset &__lhs, const dynamic_bitset &__rhs) noexcept
class reference

class std::tr2::dynamic_bitset< _WordT, _Alloc >"The dynamic_bitset class represents a sequence of bits.

See N2050, Proposal to Add a Dynamically Sizeable Bitset to the Standard Library. http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2006/n2050.pdf

In the general unoptimized case, storage is allocated in word-sized blocks. Let B be the number of bits in a word, then (Nb+(B-1))/B words will be used for storage. B - NbB bits are unused. (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 dynamic_bitset as 'a simple array of bits,' be aware that your mental picture is reversed: a dynamic_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 Nb-1 in the 'most significant / left-hand' position. Thus, unlike other containers, a dynamic_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.

#include <dynamic_bitset>
#include <iostream>
#include <sstream>

using namespace std;

int main()
{
    long         a = 'a';
    dynamic_bitset<> 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;
}

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

Extra confusion can result due to the fact that the storage for __dynamic_bitset_base is a vector, and is indexed as such. This is carefully encapsulated.

All bits set to zero.

All bits set to zero.

Initial bits bitwise-copied from a single word (others set to zero).

Use a subset of a string.

Parameters

Exceptions

std::out_of_range If __pos is bigger the size of __str.
std::invalid_argument If a character appears in the string which is neither '0' nor '1'.

Construct from a string.

Parameters

Exceptions

std::invalid_argument If a character appears in the string which is neither '0' nor '1'.

Copy constructor.

Move constructor.

Tests whether all the bits are on.

Returns

True if all the bits are set.

Tests whether any of the bits are on.

Returns

True if at least one bit is set.

Append an iterator range of blocks.

Append a block.

Clear the bitset.

Returns the number of bits which are set.

Returns true if the dynamic_bitset is empty.

Finds the index of the first 'on' bit.

Returns

The index of the first bit set, or size() if not found.

See also

find_next

Finds the index of the next 'on' bit after prev.

Returns

The index of the next bit set, or size() if not found.

Parameters

See also

find_first

Toggles every bit to its opposite value.

Toggles a given bit to its opposite value.

Parameters

Exceptions

std::out_of_range If __pos is bigger the size of the set.

Return the allocator for the bitset.

Returns the maximum size of a dynamic_bitset object having the same type as *this. The real answer is max() * bits_per_block but is likely to overflow.

Tests whether any of the bits are on.

Returns

True if none of the bits are set.

Returns the total number of blocks.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

Self-explanatory.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

Copy assignment operator.

Move assignment operator.

Self-explanatory.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

Array-indexing support.

Parameters

Returns

A bool for a 'const dynamic_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.

Array-indexing support.

Parameters

Returns

A bool for a 'const dynamic_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.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

Operations on dynamic_bitsets.

Parameters

These should be self-explanatory.

See the no-argument flip().

Push a bit onto the high end of the bitset.

Sets every bit to false.

Sets a given bit to false.

Parameters

Exceptions

std::out_of_range If __pos is bigger the size of the set.

Same as writing set(__pos, false).

Resize the bitset.

Referenced by std::tr2::operator>>().

Sets every bit to true.

Sets a given bit to a particular value.

Parameters

Exceptions

std::out_of_range If __pos is bigger the size of the set.

Returns the total number of bits.

Referenced by std::tr2::operator>>().

Swap with another bitset.

Tests the value of a bit.

Parameters

Returns

The value at __pos.

Exceptions

std::out_of_range If __pos is bigger the size of the set.

Returns a character interpretation of the dynamic_bitset.

Returns

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).

Returns a numerical interpretation of the dynamic_bitset.

Returns

The integral equivalent of the bits.

Exceptions

std::overflow_error If there are too many bits to be represented in an unsigned long.

Returns a numerical interpretation of the dynamic_bitset.

Returns

The integral equivalent of the bits.

Exceptions

std::overflow_error If there are too many bits to be represented in an unsigned long.