drwnBitArray Class Reference

Implements an efficient packed array of bits. More...

Public Member Functions
	drwnBitArray (int sz)
	creates an array with sz bits
	drwnBitArray (const drwnBitArray &m)
	copy constructor
bool	empty () const
	returns true if the array is empty
int	size () const
	returns the number of bits in the array
int	count () const
	counts the number of bits in the array that are set
bool	get (int i) const
	returns true if the i-th bit of the array is set
void	set (int i)
	sets the i-th bit of the array to true
void	clear (int i)
	sets the i-th bit of the array to false
void	flip (int i)
	negates the i-th bit of the array
drwnBitArray &	ones ()
	sets all bits in the array
drwnBitArray &	zeros ()
	clears all bits in the array
drwnBitArray &	negate ()
	flips all bits in the array
drwnBitArray &	bitwiseand (const drwnBitArray &c)
	performs a bitwise and with an array of equal size
drwnBitArray &	bitwiseor (const drwnBitArray &c)
	performs a bitwise or with an array of equal size
drwnBitArray &	bitwisenand (const drwnBitArray &c)
	performs a bitwise nand with an array of equal size
drwnBitArray &	bitwisenor (const drwnBitArray &c)
	performs a bitwise nor with an array of equal size
drwnBitArray &	bitwisexor (const drwnBitArray &c)
	performs a bitwise xor with an array of equal size
drwnBitArray &	operator= (const drwnBitArray &c)
	assignment operator
bool	operator== (const drwnBitArray &c) const
	equality operator (returns true if arrays are the same size and all bits are equal)
bool	operator!= (const drwnBitArray &c) const
	not-equality operator (returns true if arrays are different sizes or some bits are not equal)
bool	operator<= (const drwnBitArray &c) const
	less-than operator (returns true if this array preceeds c lexigraphically when printed)
bool	operator[] (int i) const
	returns true if the i-th bit of the array is set (see drwnBitArray::get)
void	print (ostream &os=cout, int stride=-1) const
	prints the array as a string of 1's and 0's

Protected Attributes
int	_sz
	size of the array in bits
int	_map_sz
	size of the array in words
int *	_map
	storage for the array
int	_mask
	mask for the last word in _map

Static Protected Attributes
static const int	NUMSETLOOKUP [256]
	lookup table for counting the number of set bits

Detailed Description

Implements an efficient packed array of bits.

For example the following code creates two arrays of size eight and counts the number of bits set when one array is xor'd with the other.

drwnBitArray a(8), b(8);
a.ones(); b.zeros();
cout << a.bitwisexor(b).count();

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

• drwnBitArray.h
• drwnBitArray.cpp