io.nem.core.utils

Class ArrayUtils

java.lang.Object

io.nem.core.utils.ArrayUtils

public class ArrayUtils
extends java.lang.Object

Static class that contains a handful of array helper functions.

Constructor Summary

Constructors

Constructor and Description
ArrayUtils()

Method Summary

Modifier and Type	Method and Description
static int	compare(byte[] b, byte[] c) NON constant-time lexicographical byte[] comparison.
static byte[]	concat(byte[]... arrays) Concatenates byte arrays and returns the result.
static byte[]	duplicate(byte[] src) Creates duplicate of given array
static int	getBit(byte[] h, int i) Gets the i'th bit of a byte array.
static int	isEqualConstantTime(byte[] b, byte[] c) Constant-time byte[] comparison.
static byte[][]	split(byte[] bytes, int splitIndex) Splits a single array into two arrays.
static java.math.BigInteger	toBigInteger(byte[] bytes) Converts a little endian byte array to a BigInteger.
static byte[]	toByteArray(java.math.BigInteger value, int numBytes) Converts a BigInteger to a little endian byte array.

Methods inherited from class java.lang.Object

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

Constructor Detail

ArrayUtils

public ArrayUtils()

Method Detail

duplicate

public static byte[] duplicate(byte[] src)

Creates duplicate of given array

Parameters:

src - The array to duplicate.

Returns:

A copy of the array.

concat

public static byte[] concat(byte[]... arrays)

Concatenates byte arrays and returns the result.

Parameters:

arrays - The arrays.

Returns:

A single array containing all elements in all arrays.

split

public static byte[][] split(byte[] bytes,
                             int splitIndex)

Splits a single array into two arrays.

Parameters:

bytes - The input array.

splitIndex - The index at which the array should be split.

Returns:

Two arrays split at the splitIndex. The first array will contain the first splitIndex elements. The second array will contain all trailing elements.

toByteArray

public static byte[] toByteArray(java.math.BigInteger value,
                                 int numBytes)

Converts a BigInteger to a little endian byte array.

Parameters:

value - The value to convert.

numBytes - The number of bytes in the destination array.

Returns:

The resulting little endian byte array.

toBigInteger

public static java.math.BigInteger toBigInteger(byte[] bytes)

Converts a little endian byte array to a BigInteger.

Parameters:

bytes - The bytes to convert.

Returns:

The resulting BigInteger.

isEqualConstantTime

public static int isEqualConstantTime(byte[] b,
                                      byte[] c)

Constant-time byte[] comparison. The constant time behavior eliminates side channel attacks.

Parameters:

b - An array.

c - An array.

Returns:

1 if b and c are equal, 0 otherwise.

compare

public static int compare(byte[] b,
                          byte[] c)

NON constant-time lexicographical byte[] comparison.

Parameters:

b - first of arrays to compare.

c - second of arrays to compare.

Returns:

1, -1, or 0 depending on comparison result.

getBit

public static int getBit(byte[] h,
                         int i)

Gets the i'th bit of a byte array.

Parameters:

h - The byte array.

i - The bit index.

Returns:

The value of the i'th bit in h