A bitset class. More...

#include </home/docs/checkouts/readthedocs.org/user_builds/axom/checkouts/develop/src/axom/slam/BitSet.hpp>

Public Types
using	Index = int

using	Word = std::uint32_t

using	ArrayType = axom::Array< Word, 1 >

Public Member Functions
	BitSet (int numBits=0, int allocatorID=axom::getDefaultAllocatorID())
	BitSet class constructor. More...

bool	operator== (const BitSet &other) const
	Equality operator for two bitsets. More...

bool	operator!= (const BitSet &other) const
	Inequality operator for two bitsets. More...

AXOM_HOST_DEVICE const Word *	data () const
	Gets the underlying data of a BitSet. More...

Bitset bitwise assignment operators
BitSet &	operator\|= (const BitSet &other)
	BitSet union-assignment operator. More...

BitSet &	operator&= (const BitSet &other)
	BitSet intersection-assignment operator. More...

BitSet &	operator^= (const BitSet &other)
	BitSet exclusive-or-assignment operator. More...

BitSet &	operator-= (const BitSet &other)
	BitSet difference-assignment operator. More...

Bitset iteration interface
Index	find_first () const
	Finds the index of the first bit that is set in the bitset. More...

Index	find_next (Index idx) const
	Finds the index of the next set bit in the bitset after idx. More...

Operations that affect all bits in the bitset
AXOM_HOST_DEVICE int	size () const
	Returns the cardinality of the bitset. More...

int	count () const
	Returns the number of bits that are set. More...

void	clear ()
	Clears all bits in the bitset. More...

void	set ()
	Sets all bits in the bitset. More...

void	flip ()
	Toggles all bits in the bitset. More...

bool	isValid () const
	Checks if the bitset instance is valid. More...

Operations that affect a single bits in the bitset
void	clear (Index idx)
	Clears bit at index idx. More...

void	set (Index idx)
	Sets bit at index idx. More...

void	flip (Index idx)
	Toggles bit at index idx. More...

bool	test (Index idx) const
	Tests the bit at index idx. More...

Atomic versions of single-bit operations
void	atomicClear (Index idx)
	Clears bit at index idx. More...

AXOM_HOST_DEVICE void	atomicSet (Index idx)
	Sets bit at index idx. More...

void	atomicFlip (Index idx)
	Toggles bit at index idx. More...

Static Public Attributes
static constexpr Index	npos = -2

static constexpr int	BitsPerWord = axom::utilities::BitTraits<Word>::BITS_PER_WORD

Detailed Description

A bitset class.

This class supports bitwise manipulation operations (e.g. set intersection, union and difference) on an ordered set of bits. The class has a similar interface to std::bitset and boost::dynamic_bitset, but with the following differences:

The size of the bitset is supplied at runtime in the class constructor. However, BitSet does not currently support changing the size after construction.
We do not support the random access operation ( operator[](index) ). The value of individual bits can be checked using the test function (e.g. bset.test(i) )
There is no support for directly initializing the bits in the bitset (e.g. via strings).

The individual bits in the bitset are packed into a contiguous array of Words (an unsigned integer type). Many bitset operations such as count() and flip() are performed at the granularity of a word.

BitSet uses the same interface as boost::dynamic_bitset to enumerate the set bits. Specifically, find_first() returns the index of the first set bit. and find_next(idx) returns the next bit that is set after bit index idx. BitSet::npos is used as a sentinel to indicate no more set bits.

Member Typedef Documentation

◆ Index

using axom::slam::BitSet::Index = int

◆ Word

using axom::slam::BitSet::Word = std::uint32_t

◆ ArrayType

using axom::slam::BitSet::ArrayType = axom::Array<Word, 1>

Constructor & Destructor Documentation

◆ BitSet()

axom::slam::BitSet::BitSet	(	int	numBits = `0`,
		int	allocatorID = `axom::getDefaultAllocatorID()`
	)

inlineexplicit

BitSet class constructor.

Parameters

numBits The number of bits in the bitset.

Precondition: numBits must be non-negative

Postcondition: bset.size() == numBits; All bits will be off

References BitsPerWord, axom::Array< T, DIM, SPACE, StoragePolicy >::fill(), axom::utilities::max(), and SLIC_ASSERT_MSG.

Member Function Documentation

◆ operator==()

bool axom::slam::BitSet::operator== ( const BitSet & other ) const

Equality operator for two bitsets.

◆ operator!=()

bool axom::slam::BitSet::operator!= ( const BitSet & other ) const

inline

Inequality operator for two bitsets.

References operator==().

◆ data()

AXOM_HOST_DEVICE const Word* axom::slam::BitSet::data ( ) const

inline

Gets the underlying data of a BitSet.

References axom::Array< T, DIM, SPACE, StoragePolicy >::data().

◆ operator|=()

BitSet& axom::slam::BitSet::operator|= ( const BitSet & other )

BitSet union-assignment operator.

Parameters

other The other bitset

Precondition: other.size() == size()

Returns: A reference to the modified bitset

Set union of the current instance and other. The i^th bit will be set if it is set in this bitset or in other

◆ operator&=()

BitSet& axom::slam::BitSet::operator&= ( const BitSet & other )

BitSet intersection-assignment operator.

Parameters

other The other bitset

Precondition: other.size() == size()

Returns: A reference to the modified bitset

Set intersection of the current instance and other. The i^th bit will be set if it is set in this bitset and in other

◆ operator^=()

BitSet& axom::slam::BitSet::operator^= ( const BitSet & other )

BitSet exclusive-or-assignment operator.

Parameters

other The other bitset

Precondition: other.size() == size()

Returns: A reference to the modified bitset

Set exclusive-or of the current instance and other. The i^th bit will be set if it is set in this bitset or in other, but not both.

◆ operator-=()

BitSet& axom::slam::BitSet::operator-= ( const BitSet & other )

BitSet difference-assignment operator.

Parameters

other The other bitset

Precondition: other.size() == size()

Returns: A reference to the modified bitset

Set difference of the current instance and other. The i^th bit will be set if it is set in this bitset and not in other

◆ find_first()

Index axom::slam::BitSet::find_first ( ) const

Finds the index of the first bit that is set in the bitset.

Returns: The index of the first set bit, or BitSet::npos if no bits are set

◆ find_next()

Index axom::slam::BitSet::find_next ( Index idx ) const

Finds the index of the next set bit in the bitset after idx.

Parameters

idx	The starting index

Returns: The index of the first set bit after index idx or BitSet::npos if none can be found

Note: Will also return BitSet::npos if idx is BitSet::npos

◆ size()

AXOM_HOST_DEVICE int axom::slam::BitSet::size ( ) const

inline

Returns the cardinality of the bitset.

◆ count()

int axom::slam::BitSet::count ( ) const

Returns the number of bits that are set.

◆ clear() [1/2]

void axom::slam::BitSet::clear ( )

Clears all bits in the bitset.

◆ set() [1/2]

void axom::slam::BitSet::set ( )

Sets all bits in the bitset.

◆ flip() [1/2]

void axom::slam::BitSet::flip ( )

Toggles all bits in the bitset.

◆ isValid()

bool axom::slam::BitSet::isValid ( ) const

Checks if the bitset instance is valid.

Returns: True if the bitset is valid, false otherwise

A bitset is valid if it has sufficient storage for size() bits. If we have storage for more than size() bits, none of these additional bits are set.

◆ clear() [2/2]

void axom::slam::BitSet::clear ( Index idx )

inline

Clears bit at index idx.

Precondition: idx must be between 0 and bitset.size()

◆ set() [2/2]

void axom::slam::BitSet::set ( Index idx )

inline

Sets bit at index idx.

Precondition: idx must be between 0 and bitset.size()

◆ flip() [2/2]

void axom::slam::BitSet::flip ( Index idx )

inline

Toggles bit at index idx.

Precondition: idx must be between 0 and bitset.size()

◆ test()

bool axom::slam::BitSet::test ( Index idx ) const

inline

Tests the bit at index idx.

Returns: True if idx is valid and its bit is set, false otherwise

◆ atomicClear()

void axom::slam::BitSet::atomicClear ( Index idx )

inline

Clears bit at index idx.

Precondition: idx must be between 0 and bitset.size()

◆ atomicSet()

AXOM_HOST_DEVICE void axom::slam::BitSet::atomicSet ( Index idx )

inline

Sets bit at index idx.

Precondition: idx must be between 0 and bitset.size()

◆ atomicFlip()

void axom::slam::BitSet::atomicFlip ( Index idx )

inline

Toggles bit at index idx.

Precondition: idx must be between 0 and bitset.size()

Member Data Documentation

◆ npos

constexpr Index axom::slam::BitSet::npos = -2

staticconstexpr

◆ BitsPerWord

constexpr int axom::slam::BitSet::BitsPerWord = axom::utilities::BitTraits<Word>::BITS_PER_WORD

staticconstexpr

The documentation for this class was generated from the following file:

/home/docs/checkouts/readthedocs.org/user_builds/axom/checkouts/develop/src/axom/slam/BitSet.hpp

Public Types

Public Member Functions

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ Index

◆ Word

◆ ArrayType

Constructor & Destructor Documentation

◆ BitSet()

Member Function Documentation

◆ operator==()

◆ operator!=()

◆ data()

◆ operator|=()

◆ operator&=()

◆ operator^=()

◆ operator-=()

◆ find_first()

◆ find_next()

◆ size()

◆ count()

◆ clear() [1/2]

◆ set() [1/2]

◆ flip() [1/2]

◆ isValid()

◆ clear() [2/2]

◆ set() [2/2]

◆ flip() [2/2]

◆ test()

◆ atomicClear()

◆ atomicSet()

◆ atomicFlip()

Member Data Documentation

◆ npos

◆ BitsPerWord