H2 Database Engine 2.3.232 · org.h2.util.MathUtils · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
pack-priv static SecureRandom	secureRandom The secure random object.
pack-priv static volatile boolean	seeded True if the secure random object is seeded.

Access	Constructor and Description
private	MathUtils()

Method Summary

Modifier and Type	Method and Description
public static short	Returns: the converted short value convertIntToShort(int the value to convert i) Convert an int value to a short value.
public static int	Returns: the converted int value convertLongToInt(long the value to convert l) Convert a long value to an int value.
public static byte[]	Returns: the seed generateAlternativeSeed() Generate a seed value, using as much unpredictable data as possible.
private static synchronized SecureRandom	getSecureRandom()
public static int	Returns: the next power of two value nextPowerOf2(int the original value x) Get the value that is equal to or higher than this value, and that is a power of two.
public static void	randomBytes(byte[] the target array bytes) Get a number of pseudo random bytes.
public static int	Returns: the random long value randomInt(int the value returned will be lower than this value lowerThan) Get a pseudo random int value between 0 (including and the given value (excluding).
public static int	Returns: the rounded value roundUpInt(int the value to be rounded x, int the block size blockSizePowerOf2) Round the value up to the next block size.
public static long	Returns: the rounded value roundUpLong(long the value to be rounded x, long the block size blockSizePowerOf2) Round the value up to the next block size.
public static byte[]	Returns: the random bytes secureRandomBytes(int the number of bytes len) Get a number of cryptographically secure pseudo random bytes.
public static int	Returns: the random long value secureRandomInt(int the value returned will be lower than this value lowerThan) Get a cryptographically secure pseudo random int value between 0 (including and the given value (excluding).
public static long	Returns: the random long value secureRandomLong() Get a cryptographically secure pseudo random long value.
pack-priv static void	warn(String the message to print s, Throwable the stack trace t) Print a message to system output if there was a problem initializing the random number generator.

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

secureRandom	back to summary
pack-priv static SecureRandom secureRandom The secure random object.

seeded	back to summary
pack-priv static volatile boolean seeded True if the secure random object is seeded.

MathUtils	back to summary
private MathUtils()

Method Detail

convertIntToShort	back to summary
public static short convertIntToShort(int i) Convert an int value to a short value. Values larger than the biggest short value are converted to the biggest short value, and values smaller than the smallest short value are converted to the smallest short value. Parameters i:int the value to convert Returns:short the converted short value

convertIntToShort

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public static short convertIntToShort(int i)

Convert an int value to a short value. Values larger than the biggest short value are converted to the biggest short value, and values smaller than the smallest short value are converted to the smallest short value.

Parameters

i:int: the value to convert

Returns:short

the converted short value

convertLongToInt	back to summary
public static int convertLongToInt(long l) Convert a long value to an int value. Values larger than the biggest int value are converted to the biggest int value, and values smaller than the smallest int value are converted to the smallest int value. Parameters l:long the value to convert Returns:int the converted int value

convertLongToInt

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public static int convertLongToInt(long l)

Convert a long value to an int value. Values larger than the biggest int value are converted to the biggest int value, and values smaller than the smallest int value are converted to the smallest int value.

Parameters

l:long: the value to convert

Returns:int

the converted int value

generateAlternativeSeed	back to summary
public static byte[] generateAlternativeSeed() Generate a seed value, using as much unpredictable data as possible. Returns:byte[] the seed

generateAlternativeSeed

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public static byte[] generateAlternativeSeed()

Generate a seed value, using as much unpredictable data as possible.

Returns:byte[]: the seed

getSecureRandom	back to summary
private static synchronized SecureRandom getSecureRandom()

nextPowerOf2	back to summary
public static int nextPowerOf2(int x) throws IllegalArgumentException Get the value that is equal to or higher than this value, and that is a power of two. Parameters x:int the original value Returns:int the next power of two value Exceptions IllegalArgumentException: if x < 0 or x > 0x40000000

nextPowerOf2

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public static int nextPowerOf2(int x) throws IllegalArgumentException

Get the value that is equal to or higher than this value, and that is a power of two.

Parameters

x:int: the original value

Returns:int

the next power of two value

Exceptions

IllegalArgumentException:: if x < 0 or x > 0x40000000

randomBytes	back to summary
public static void randomBytes(byte[] bytes) Get a number of pseudo random bytes. Parameters bytes:byte[] the target array

randomBytes

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public static void randomBytes(byte[] bytes)

Get a number of pseudo random bytes.

Parameters

bytes:byte[]: the target array

randomInt	back to summary
public static int randomInt(int lowerThan) Get a pseudo random int value between 0 (including and the given value (excluding). The value is not cryptographically secure. Parameters lowerThan:int the value returned will be lower than this value Returns:int the random long value

randomInt

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public static int randomInt(int lowerThan)

Get a pseudo random int value between 0 (including and the given value (excluding). The value is not cryptographically secure.

Parameters

lowerThan:int: the value returned will be lower than this value

Returns:int

the random long value

roundUpInt	back to summary
public static int roundUpInt(int x, int blockSizePowerOf2) Round the value up to the next block size. The block size must be a power of two. As an example, using the block size of 8, the following rounding operations are done: 0 stays 0; values 1..8 results in 8, 9..16 results in 16, and so on. Parameters x:int the value to be rounded blockSizePowerOf2:int the block size Returns:int the rounded value

roundUpInt

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public static int roundUpInt(int x, int blockSizePowerOf2)

Round the value up to the next block size. The block size must be a power of two. As an example, using the block size of 8, the following rounding operations are done: 0 stays 0; values 1..8 results in 8, 9..16 results in 16, and so on.

Parameters

x:int: the value to be rounded
blockSizePowerOf2:int: the block size

Returns:int

the rounded value

roundUpLong	back to summary
public static long roundUpLong(long x, long blockSizePowerOf2) Round the value up to the next block size. The block size must be a power of two. As an example, using the block size of 8, the following rounding operations are done: 0 stays 0; values 1..8 results in 8, 9..16 results in 16, and so on. Parameters x:long the value to be rounded blockSizePowerOf2:long the block size Returns:long the rounded value

roundUpLong

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public static long roundUpLong(long x, long blockSizePowerOf2)

Parameters

x:long: the value to be rounded
blockSizePowerOf2:long: the block size

Returns:long

the rounded value

secureRandomBytes	back to summary
public static byte[] secureRandomBytes(int len) Get a number of cryptographically secure pseudo random bytes. Parameters len:int the number of bytes Returns:byte[] the random bytes

secureRandomBytes

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public static byte[] secureRandomBytes(int len)

Get a number of cryptographically secure pseudo random bytes.

Parameters

len:int: the number of bytes

Returns:byte[]

the random bytes

secureRandomInt	back to summary
public static int secureRandomInt(int lowerThan) Get a cryptographically secure pseudo random int value between 0 (including and the given value (excluding). Parameters lowerThan:int the value returned will be lower than this value Returns:int the random long value

secureRandomInt

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public static int secureRandomInt(int lowerThan)

Get a cryptographically secure pseudo random int value between 0 (including and the given value (excluding).

Parameters

lowerThan:int: the value returned will be lower than this value

Returns:int

the random long value

secureRandomLong	back to summary
public static long secureRandomLong() Get a cryptographically secure pseudo random long value. Returns:long the random long value

secureRandomLong

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public static long secureRandomLong()

Get a cryptographically secure pseudo random long value.

Returns:long: the random long value

warn	back to summary
pack-priv static void warn(String s, Throwable t) Print a message to system output if there was a problem initializing the random number generator. Parameters s:String the message to print t:Throwable the stack trace

warn

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pack-priv static void warn(String s, Throwable t)

Print a message to system output if there was a problem initializing the random number generator.

Parameters

s:String: the message to print
t:Throwable: the stack trace

public Class MathUtils

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Constructor Summary

Method Summary

Field Detail

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Method Detail