org.h2.util
Class Utils

java.lang.Object
  org.h2.util.Utils

public class Utils
extends java.lang.Object

This utility class contains miscellaneous functions.

Field Summary

static byte[]	EMPTY_BYTES An 0-size byte array.
static int[]	EMPTY_INT_ARRAY An 0-size int array.

Method Summary

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 java.lang.Object	deserialize(byte[] data) De-serialize the byte array to an object.
static int	getByteArrayHash(byte[] value) Calculate the hash code of the given byte array.
static int	getMemoryFree() Get the free memory in KB.
static long	getMemoryMax() Get the maximum memory in KB.
static int	getMemoryUsed() Get the used memory in KB.
static byte[]	getResource(java.lang.String name) Get a resource from the resource map.
static int	hashCode(java.lang.Object o) Calculate the hash code of the given object.
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 java.lang.Class<?>	loadUserClass(java.lang.String className) Load a class, but check if it is allowed to load this class first.
static byte[]	newBytes(int len) Create an array of bytes with the given size.
static int[]	newIntArray(int len) Create an int array with the given size.
static long[]	newLongArray(int len) Create a long array with the given size.
static long	readLong(byte[] buff, int pos) Read a long value from the byte array at the given position.
static byte[]	serialize(java.lang.Object obj) Serialize the object to a byte array.
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

Field Detail

EMPTY_BYTES

public static final byte[] EMPTY_BYTES

An 0-size byte array.

EMPTY_INT_ARRAY

public static final int[] EMPTY_INT_ARRAY

An 0-size int array.

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)

Convert a hex encoded string to a byte array.

Parameters:

s - the hex encoded string

Returns:

the byte array

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

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

serialize

public static byte[] serialize(java.lang.Object obj)

Serialize the object to a byte array.

Parameters:

obj - the object to serialize

Returns:

the byte array

deserialize

public static java.lang.Object deserialize(byte[] data)

De-serialize the byte array to an object.

Parameters:

data - the byte array

Returns:

the object

Throws:

SQLException

hashCode

public static int hashCode(java.lang.Object o)

Calculate the hash code of the given object. The object may be null.

Parameters:

o - the object

Returns:

the hash code, or 0 if the object is null

getMemoryUsed

public static int getMemoryUsed()

Get the used memory in KB. This method possibly calls System.gc().

Returns:

the used memory

getMemoryFree

public static int getMemoryFree()

Get the free memory in KB. This method possibly calls System.gc().

Returns:

the free memory

getMemoryMax

public static long getMemoryMax()

Get the maximum memory in KB.

Returns:

the maximum memory

newBytes

public static byte[] newBytes(int len)

Create an array of bytes with the given size. If this is not possible because not enough memory is available, an OutOfMemoryError with the requested size in the message is thrown.

Parameters:

len - the number of bytes requested

Returns:

the byte array

Throws:

java.lang.OutOfMemoryError

newIntArray

public static int[] newIntArray(int len)

Create an int array with the given size.

Parameters:

len - the number of bytes requested

Returns:

the int array

newLongArray

public static long[] newLongArray(int len)

Create a long array with the given size.

Parameters:

len - the number of bytes requested

Returns:

the int array

loadUserClass

public static java.lang.Class<?> loadUserClass(java.lang.String className)

Load a class, but check if it is allowed to load this class first. To perform access rights checking, the system property h2.allowedClasses needs to be set to a list of class file name prefixes.

Parameters:

className - the name of the class

Returns:

the class object

getResource

public static byte[] getResource(java.lang.String name)
                          throws java.io.IOException

Get a resource from the resource map.

Parameters:

name - the name of the resource

Returns:

the resource data

Throws:

java.io.IOException