ewe.math
Class BigInteger

java.lang.Object
  ewe.math.Number
      ewe.math.BigInteger

All Implemented Interfaces:

ByteEncodable, Comparable

public class BigInteger

extends Number

implements Comparable, ByteEncodable

Written using on-line Java Platform 1.2 API Specification, as well as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998) and "Applied Cryptography, Second Edition" by Bruce Schneier (Wiley, 1996). Based primarily on IntNum.java BitOps.java by Per Bothner (found in Kawa 1.6.62). Status: Believed complete and correct.

Field Summary

static BigInteger	ONE
static BigInteger	ZERO

Fields inherited from class ewe.math.Number

DOUBLE_MAX_VALUE, DOUBLE_MIN_VALUE, INTEGER_MAX_VALUE, INTEGER_MIN_VALUE, LONG_MAX_VALUE, LONG_MIN_VALUE, NEGATIVE_INFINITY, POSITIVE_INFINITY

Constructor Summary

BigInteger(byte[] val)

BigInteger(byte[] val, int offset, int numBytes)

BigInteger(int value)

BigInteger(int signum, byte[] magnitude)

BigInteger(int bitLength, int certainty, Random rnd)

BigInteger(int numBits, Random rnd)

BigInteger(String val)

BigInteger(String val, int radix)

Method Summary

BigInteger	abs()
BigInteger	add(BigInteger val)
BigInteger	and(BigInteger y) Return the logical (bit-wise) "and" of two BigIntegers.
BigInteger	andNot(BigInteger val)
int	bitCount() Count one bits in a BigInteger.
int	bitLength() Calculates ceiling(log2(this < 0 ? -this : this+1)) See Common Lisp: the Language, 2nd ed, p.
BigInteger	clearBit(int n)
int	compareTo(BigInteger val)
int	compareTo(Object obj) Compare this object with another.
BigInteger	divide(BigInteger val)
BigInteger[]	divideAndRemainder(BigInteger val)
double	doubleValue() Return the value of this Number as a double.
int	encodeBytes(ByteArray dest) This requests the Object to encode itself as a stream of bytes which is appended to the destination ByteArray.
boolean	equals(Object obj) Returns if this object is considered equal to the other object.
BigInteger	flipBit(int n)
float	floatValue() Return the value of this Number as a float.
BigInteger	gcd(BigInteger y)
int	getLowestSetBit()
int	hashCode() Returns a hashCode for the object.
int	intValue() Return the value of this Number as an int.
boolean	isProbablePrime(int certainty) Returns true if this BigInteger is probably prime, false if it's definitely composite.
long	longValue() Return the value of this Number as a long.
BigInteger	max(BigInteger val)
BigInteger	min(BigInteger val)
BigInteger	mod(BigInteger m)
BigInteger	modInverse(BigInteger y)
BigInteger	modPow(BigInteger exponent, BigInteger m)
BigInteger	multiply(BigInteger y)
BigInteger	negate()
BigInteger	not() Return the logical (bit-wise) negation of a BigInteger.
BigInteger	or(BigInteger y) Return the logical (bit-wise) "(inclusive) or" of two BigIntegers.
BigInteger	pow(int exponent) Calculate the integral power of a BigInteger.
static BigInteger	probablePrime(int bitLength, Random rnd) Return a BigInteger that is bitLength bits long with a probability < 2^-100 of being composite.
BigInteger	remainder(BigInteger val)
BigInteger	setBit(int n)
BigInteger	shiftLeft(int n)
BigInteger	shiftRight(int n)
int	signum()
BigInteger	subtract(BigInteger val)
boolean	testBit(int n)
byte[]	toByteArray()
String	toString() Return a String representation of this object.
String	toString(int radix)
static BigInteger	valueOf(long val) Return a (possibly-shared) BigInteger with a given long value.
int	write(byte[] bytes, int offset) Write the BigInteger as a series of bytes, or find out how many bytes are needed for storing the BigInteger.
BigInteger	xor(BigInteger y) Return the logical (bit-wise) "exclusive or" of two BigIntegers.

Methods inherited from class ewe.math.Number

byteValue, digit, forDigit, isInfinite, isNaN, shortValue

Methods inherited from class java.lang.Object

clone, finalize, getClass

Field Detail

ZERO

public static final BigInteger ZERO

ONE

public static final BigInteger ONE

Constructor Detail

BigInteger

public BigInteger(int value)

BigInteger

public BigInteger(String val,
                  int radix)

BigInteger

public BigInteger(String val)

BigInteger

public BigInteger(byte[] val)

BigInteger

public BigInteger(byte[] val,
                  int offset,
                  int numBytes)

BigInteger

public BigInteger(int signum,
                  byte[] magnitude)

BigInteger

public BigInteger(int numBits,
                  Random rnd)

BigInteger

public BigInteger(int bitLength,
                  int certainty,
                  Random rnd)

Method Detail

probablePrime

public static BigInteger probablePrime(int bitLength,
                                       Random rnd)

Return a BigInteger that is bitLength bits long with a probability < 2^-100 of being composite.

Parameters:

bitLength - length in bits of resulting number

rnd - random number generator to use

Throws:

ArithmeticException - if bitLength < 2

Since:

1.4

valueOf

public static BigInteger valueOf(long val)

Return a (possibly-shared) BigInteger with a given long value.

signum

public int signum()

compareTo

public int compareTo(Object obj)

Description copied from interface: Comparable

Compare this object with another. It should return: less than 0 if this object is considered LESS than the "other" object; greater than 0 if this object is considered GREATER than the "other" object; 0 if this object is considered EQUAL to the "other" object. (i.e. it is an implicit subtraction).

Specified by:

compareTo in interface Comparable

compareTo

public int compareTo(BigInteger val)

min

public BigInteger min(BigInteger val)

max

public BigInteger max(BigInteger val)

add

public BigInteger add(BigInteger val)

subtract

public BigInteger subtract(BigInteger val)

multiply

public BigInteger multiply(BigInteger y)

divide

public BigInteger divide(BigInteger val)

remainder

public BigInteger remainder(BigInteger val)

divideAndRemainder

public BigInteger[] divideAndRemainder(BigInteger val)

mod

public BigInteger mod(BigInteger m)

pow

public BigInteger pow(int exponent)

Calculate the integral power of a BigInteger.

Parameters:

exponent - the exponent (must be non-negative)

modInverse

public BigInteger modInverse(BigInteger y)

modPow

public BigInteger modPow(BigInteger exponent,
                         BigInteger m)

gcd

public BigInteger gcd(BigInteger y)

isProbablePrime

public boolean isProbablePrime(int certainty)

Returns true if this BigInteger is probably prime, false if it's definitely composite. If certainty is <= 0, true is returned.

Parameters:

certainty - a measure of the uncertainty that the caller is willing to tolerate: if the call returns true the probability that this BigInteger is prime exceeds (1 - 1/2certainty). The execution time of this method is proportional to the value of this parameter.

Returns:

true if this BigInteger is probably prime, false if it's definitely composite.

shiftLeft

public BigInteger shiftLeft(int n)

shiftRight

public BigInteger shiftRight(int n)

toString

public String toString()

Description copied from class: Object

Return a String representation of this object.

Overrides:

toString in class Object

Returns:

a String representing this object.

toString

public String toString(int radix)

intValue

public int intValue()

Description copied from class: Number

Return the value of this Number as an int.

Specified by:

intValue in class Number

Returns:

the int value

longValue

public long longValue()

Description copied from class: Number

Return the value of this Number as a long.

Specified by:

longValue in class Number

Returns:

the long value

hashCode

public int hashCode()

Description copied from class: Object

Returns a hashCode for the object. The general contract of hashCode is:

An object must return the same hash code for its entire existence.

If two objects are considered equal by the equals() method, they should return the same hash code. Not all Objects will do this and you should only use hashCode() from Objects which declare an overrided version of hashCode(). The only Objects which provide consistent and correct hash codes under Ewe are Object, String and Class.

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Description copied from class: Object

Returns if this object is considered equal to the other object.

Overrides:

equals in class Object

Parameters:

obj - Another object to compare to.

Returns:

true if this object is considered equal to the other object.

doubleValue

public double doubleValue()

Description copied from class: Number

Return the value of this Number as a double.

Specified by:

doubleValue in class Number

Returns:

the double value

floatValue

public float floatValue()

Description copied from class: Number

Return the value of this Number as a float.

Specified by:

floatValue in class Number

Returns:

the float value

abs

public BigInteger abs()

negate

public BigInteger negate()

bitLength

public int bitLength()

Calculates ceiling(log2(this < 0 ? -this : this+1)) See Common Lisp: the Language, 2nd ed, p. 361.

toByteArray

public byte[] toByteArray()

write

public int write(byte[] bytes,
                 int offset)

Write the BigInteger as a series of bytes, or find out how many bytes are needed for storing the BigInteger.

Parameters:

offset - The offset in the byte array to write to.

Returns:

The number of bytes written or needed to be written.

and

public BigInteger and(BigInteger y)

Return the logical (bit-wise) "and" of two BigIntegers.

or

public BigInteger or(BigInteger y)

Return the logical (bit-wise) "(inclusive) or" of two BigIntegers.

xor

public BigInteger xor(BigInteger y)

Return the logical (bit-wise) "exclusive or" of two BigIntegers.

not

public BigInteger not()

Return the logical (bit-wise) negation of a BigInteger.

andNot

public BigInteger andNot(BigInteger val)

clearBit

public BigInteger clearBit(int n)

setBit

public BigInteger setBit(int n)

testBit

public boolean testBit(int n)

flipBit

public BigInteger flipBit(int n)

getLowestSetBit

public int getLowestSetBit()

bitCount

public int bitCount()

Count one bits in a BigInteger. If argument is negative, count zero bits instead.

encodeBytes

public int encodeBytes(ByteArray dest)

Description copied from interface: ByteEncodable

This requests the Object to encode itself as a stream of bytes which is appended to the destination ByteArray. If the destination ByteArray is null, then the object should report how many bytes would be used if the object was encoded.

Specified by:

encodeBytes in interface ByteEncodable

Parameters:

dest - The destination ByteArray, or null to determine the number of bytes needed to encode.

Returns:

The number of bytes appended to the ByteArray or the number of bytes needed to encode.