org.h2.util
Class ByteUtils

java.lang.Object
  org.h2.util.ByteUtils

public class ByteUtils
extends java.lang.Object

This utility class contains functions related to byte arrays.

Method Summary

static void	clear(byte[] buff) Set all elements of the array to zero.
static byte[]	cloneByteArray(byte[] b) Create a new byte array and copy all the data.
static int	compareNotNull(byte[] data1, byte[] data2) Compare the contents of two byte arrays.
static boolean	compareSecure(byte[] test, byte[] good) Compare two byte arrays.
static java.lang.String	convertBytesToString(byte[] value) Convert a byte array to a hex encoded string.
static java.lang.String	convertBytesToString(byte[] value, int len) Convert a byte array to a hex encoded string.
static byte[]	convertStringToBytes(java.lang.String s) Convert a hex encoded string to a byte array.
static byte[]	copy(byte[] source, byte[] target) Copy the contents of the source array to the target array.
static int	getByteArrayHash(byte[] value) Calculate the hash code of the given byte array.
static int	indexOf(byte[] bytes, byte[] pattern, int start) Calculate the index of the first occurrence of the pattern in the byte array, starting with the given index.
static long	readLong(byte[] buff, int pos) Read a long value from the byte array at the given position.
static void	writeLong(byte[] buff, int pos, long x) Write a long value to the byte array.

Methods inherited from class java.lang.Object

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

Method Detail

readLong

public static long readLong(byte[] buff,
                            int pos)

Read a long value from the byte array at the given position. The most significant byte is read first.

Parameters:

buff - the byte array

pos - the position

Returns:

the value

writeLong

public static void writeLong(byte[] buff,
                             int pos,
                             long x)

Write a long value to the byte array.

Parameters:

buff - the byte array

pos - the position

x - the value

indexOf

public static int indexOf(byte[] bytes,
                          byte[] pattern,
                          int start)

Calculate the index of the first occurrence of the pattern in the byte array, starting with the given index. This methods returns -1 if the pattern has not been found, and the start position if the pattern is empty.

Parameters:

bytes - the byte array

pattern - the pattern

start - the start index from where to search

Returns:

the index

convertStringToBytes

public static byte[] convertStringToBytes(java.lang.String s)
                                   throws java.sql.SQLException

Convert a hex encoded string to a byte array.

Parameters:

s - the hex encoded string

Returns:

the byte array

Throws:

java.sql.SQLException

getByteArrayHash

public static int getByteArrayHash(byte[] value)

Calculate the hash code of the given byte array.

Parameters:

value - the byte array

Returns:

the hash code

convertBytesToString

public static java.lang.String convertBytesToString(byte[] value)

Convert a byte array to a hex encoded string.

Parameters:

value - the byte array

Returns:

the hex encoded string

convertBytesToString

public static java.lang.String convertBytesToString(byte[] value,
                                                    int len)

Convert a byte array to a hex encoded string.

Parameters:

value - the byte array

len - the number of bytes to encode

Returns:

the hex encoded string

compareSecure

public static boolean compareSecure(byte[] test,
                                    byte[] good)

Compare two byte arrays. This method will always loop over all bytes and doesn't use conditional operations in the loop to make sure an attacker can not use a timing attack when trying out passwords.

Parameters:

test - the first array

good - the second array

Returns:

true if both byte arrays contain the same bytes

clear

public static void clear(byte[] buff)

Set all elements of the array to zero.

Parameters:

buff - the byte array

compareNotNull

public static int compareNotNull(byte[] data1,
                                 byte[] data2)

Compare the contents of two byte arrays. If the content or length of the first array is smaller than the second array, -1 is returned. If the content or length of the second array is smaller than the first array, 1 is returned. If the contents and lengths are the same, 0 is returned.

Parameters:

data1 - the first byte array (must not be null)

data2 - the second byte array (must not be null)

Returns:

the result of the comparison (-1, 1 or 0)

copy

public static byte[] copy(byte[] source,
                          byte[] target)

Copy the contents of the source array to the target array. If the size if the target array is too small, a larger array is created.

Parameters:

source - the source array

target - the target array

Returns:

the target array or a new one if the target array was too small

cloneByteArray

public static byte[] cloneByteArray(byte[] b)

Create a new byte array and copy all the data. If the size of the byte array is zero, the same array is returned.

Parameters:

b - the byte array (may not be null)

Returns:

a new byte array