io.nem.symbol.core.utils

Class ArrayUtils

java.lang.Object

io.nem.symbol.core.utils.ArrayUtils

public class ArrayUtils
extends java.lang.Object

Static class that contains a handful of array helper functions.

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

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