com.revolsys.jts.precision

Class CommonBits

java.lang.Object

com.revolsys.jts.precision.CommonBits

public class CommonBits
extends Object

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.

Version:

1.7

Constructor Summary

Constructors

Constructor and Description
CommonBits()

Method Summary

Methods

Modifier and Type	Method and Description
void	add(double num)
static int	getBit(long bits, int i) Extracts the i'th bit of a bitstring.
double	getCommon()
static int	numCommonMostSigMantissaBits(long num1, long num2) This computes the number of common most-significant bits in the mantissas of two double-precision numbers.
static long	signExpBits(long num) Computes the bit pattern for the sign and exponent of a double-precision number.
String	toString(long bits) A representation of the Double bits formatted for easy readability
static long	zeroLowerBits(long bits, int nBits) Zeroes the lower n bits of a bitstring.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CommonBits

public CommonBits()

Method Detail

getBit

public static int getBit(long bits,
         int i)

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

numCommonMostSigMantissaBits

public static int numCommonMostSigMantissaBits(long num1,
                               long num2)

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 - the first number

num2 - the second number

Returns:

the number of common most-significant mantissa bits

signExpBits

public static long signExpBits(long num)

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

zeroLowerBits

public static long zeroLowerBits(long bits,
                 int nBits)

Zeroes the lower n bits of a bitstring.

Parameters:

bits - the bitstring to alter

Returns:

the zeroed bitstring

add

public void add(double num)

getCommon

public double getCommon()

toString

public String toString(long bits)

A representation of the Double bits formatted for easy readability