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org.bouncycastle.crypto.util

public Class RadixConverter

Class Inheritance

extends Object

java.lang.Object
org.bouncycastle.crypto.util.RadixConverter

Imports

java.math.BigInteger, org.bouncycastle.util.BigIntegers

Utility class to convert decimal numbers (BigInteger) into a number in the base provided and the other way round.

For an application of this see the FPE parameter classes.

Field Summary

Modifier and Type	Field and Description
private static final int	DEFAULT_POWERS_TO_CACHE
private final int	digitsGroupLength
private final BigInteger[]	digitsGroupSpacePowers
private final BigInteger	digitsGroupSpaceSize
private static final double	LOG_LONG_MAX_VALUE
private final int	radix

Constructor Summary

Access	Constructor and Description
public	RadixConverter(int the radix to use for base conversions radix, int number of intermediate base powers to precompute and cache. numberOfCachedPowers)
public	RadixConverter(int the radix to use for base conversions. radix)

Method Summary

Modifier and Type	Method and Description
public BigInteger	fromEncoding(short[] digits)
private long	fromEncoding(int groupStartDigitIndex, int groupEndDigitIndex, short[] digits)
public int	getDigitsGroupLength()
public int	getRadix()
private BigInteger[]	precomputeDigitsGroupPowers(int numberOfCachedPowers, BigInteger digitsGroupSpaceSize)
public void	toEncoding(BigInteger number, int messageLength, short[] out)
private int	toEncoding(long number, int digitIndex, short[] out)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

DEFAULT_POWERS_TO_CACHE	back to summary
private static final int DEFAULT_POWERS_TO_CACHE

digitsGroupLength	back to summary
private final int digitsGroupLength

digitsGroupSpacePowers	back to summary
private final BigInteger[] digitsGroupSpacePowers

digitsGroupSpaceSize	back to summary
private final BigInteger digitsGroupSpaceSize

LOG_LONG_MAX_VALUE	back to summary
private static final double LOG_LONG_MAX_VALUE

radix	back to summary
private final int radix

Constructor Detail

RadixConverter	back to summary
public RadixConverter(int radix, int numberOfCachedPowers) Parameters radix:int the radix to use for base conversions numberOfCachedPowers:int number of intermediate base powers to precompute and cache.

RadixConverter	back to summary
public RadixConverter(int radix) Parameters radix:int the radix to use for base conversions.

Method Detail

fromEncoding	back to summary
public BigInteger fromEncoding(short[] digits)

fromEncoding	back to summary
private long fromEncoding(int groupStartDigitIndex, int groupEndDigitIndex, short[] digits)

getDigitsGroupLength	back to summary
public int getDigitsGroupLength()

getRadix	back to summary
public int getRadix()

precomputeDigitsGroupPowers	back to summary
private BigInteger[] precomputeDigitsGroupPowers(int numberOfCachedPowers, BigInteger digitsGroupSpaceSize)

toEncoding	back to summary
public void toEncoding(BigInteger number, int messageLength, short[] out)

toEncoding	back to summary
private int toEncoding(long number, int digitIndex, short[] out)