geos::precision::CommonBits Class Reference

Determines the maximum number of common most-significant bits in the mantissa of one or numbers. More...

#include <CommonBits.h>

Public Member Functions
	CommonBits ()
void	add (double num)
double	getCommon ()

Static Public Member Functions
static int64	signExpBits (int64 num)
	Computes the bit pattern for the sign and exponent of a double-precision number. More...
static int	numCommonMostSigMantissaBits (int64 num1, int64 num2)
	This computes the number of common most-significant bits in the mantissas of two double-precision numbers. More...
static int64	zeroLowerBits (int64 bits, int nBits)
	Zeroes the lower n bits of a bitstring. More...
static int	getBit (int64 bits, int i)
	Extracts the i'th bit of a bitstring. More...

Private Attributes
bool	isFirst
int	commonMantissaBitsCount
int64	commonBits
int64	commonSignExp

Detailed Description

Determines the maximum number of common most-significant bits in the mantissa of one or numbers.

Can be used to compute the double-precision number which is represented by the common bits. If there are no common bits, the number computed is 0.0.

Definition at line 33 of file CommonBits.h.

Constructor & Destructor Documentation

geos::precision::CommonBits::CommonBits

(

)

Member Function Documentation

void geos::precision::CommonBits::add

(

double

num

)

static int geos::precision::CommonBits::getBit ( int64  bits, int  i  )

static

Extracts the i'th bit of a bitstring.

Parameters

bits	the bitstring to extract from
i	the bit to extract

Returns

the value of the extracted bit

double geos::precision::CommonBits::getCommon

(

)

static int geos::precision::CommonBits::numCommonMostSigMantissaBits ( int64  num1, int64  num2  )

static

This computes the number of common most-significant bits in the mantissas of two double-precision numbers.

It does not count the hidden bit, which is always 1. It does not determine whether the numbers have the same exponent - if they do not, the value computed by this function is meaningless.

Parameters

num1
num2

Returns

the number of common most-significant mantissa bits

static int64 geos::precision::CommonBits::signExpBits ( int64  num )

static

Computes the bit pattern for the sign and exponent of a double-precision number.

Parameters

num

Returns

the bit pattern for the sign and exponent

static int64 geos::precision::CommonBits::zeroLowerBits ( int64  bits, int  nBits  )

static

Zeroes the lower n bits of a bitstring.

Parameters

bits	the bitstring to alter
nBits	the number of bits to zero

Returns

the zeroed bitstring

Member Data Documentation

int64 geos::precision::CommonBits::commonBits

private

Definition at line 41 of file CommonBits.h.

int geos::precision::CommonBits::commonMantissaBitsCount

private

Definition at line 39 of file CommonBits.h.

int64 geos::precision::CommonBits::commonSignExp

private

Definition at line 43 of file CommonBits.h.

bool geos::precision::CommonBits::isFirst

private

Definition at line 37 of file CommonBits.h.

---

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

• CommonBits.h