Package org.apfloat.spi

Class Util

java.lang.Object

org.apfloat.spi.Util

public class Util
extends Object

Miscellaneous utility methods.

Version:

1.13.0

Author:

Mikko Tommila

Method Summary

Modifier and Type	Method	Description
static long	addExact(long x, long y)	Returns the sum of the arguments, throwing an exception if the result overflows a long.
static long	ifFinite(long x, long y)	Returns the argument y limited to Apfloat.INFINITE.
static int	log2down(int x)	Base-2 logarithm rounded down to nearest power of two.
static int	log2down(long x)	Base-2 logarithm rounded down to nearest power of two.
static int	log2up(int x)	Base-2 logarithm rounded up to nearest power of two.
static int	log2up(long x)	Base-2 logarithm rounded up to nearest power of two.
static long	max(long x, long... y)	Returns the maximum of the arguments.
static long	min(long x, long... y)	Returns the minimum of the arguments.
static long	multiplyExact(long x, long y)	Returns the product of the arguments, throwing an exception if the result overflows a long.
static int	round23down(int x)	Round down to nearest power of two or three times a power of two.
static long	round23down(long x)	Round down to nearest power of two or three times a power of two.
static int	round23up(int x)	Round up to nearest power of two or three times a power of two.
static long	round23up(long x)	Round up to nearest power of two or three times a power of two.
static int	round2down(int x)	Round down to nearest power of two.
static long	round2down(long x)	Round down to nearest power of two.
static int	round2up(int x)	Round up to nearest power of two.
static long	round2up(long x)	Round up to nearest power of two.
static int	sqrt4down(int x)	Square root rounded down to nearest power of two.
static long	sqrt4down(long x)	Square root rounded down to nearest power of two.
static int	sqrt4up(int x)	Square root rounded up to nearest power of two.
static long	sqrt4up(long x)	Square root rounded up to nearest power of two.
static <T> Stream<T>	stream(Iterator<T> iterator)	Convert iterator to stream.
static long	subtractExact(long x, long y)	Returns the difference of the arguments, throwing an exception if the result overflows a long.

Methods inherited from class java.lang.Object

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

Method Details

round2down

public static int round2down(int x)

Round down to nearest power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

x rounded down to the nearest power of two.

round2down

public static long round2down(long x)

Round down to nearest power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

x rounded down to the nearest power of two.

round2up

public static int round2up(int x)

Round up to nearest power of two.

Parameters:

x - The input value, which must be non-negative and not greater than 2³⁰.

Returns:

x rounded up to the nearest power of two.

round2up

public static long round2up(long x)

Round up to nearest power of two.

Parameters:

x - The input value, which must be non-negative and not greater than 2⁶².

Returns:

x rounded up to the nearest power of two.

round23down

public static int round23down(int x)

Round down to nearest power of two or three times a power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

x rounded down to nearest power of two or three times a power of two.

round23down

public static long round23down(long x)

Round down to nearest power of two or three times a power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

x rounded down to nearest power of two or three times a power of two.

round23up

public static int round23up(int x)

Round up to nearest power of two or three times a power of two.

Parameters:

x - The input value, which must be non-negative and not greater than 3 * 2²⁹.

Returns:

x rounded up to the nearest power of two or three times a power of two.

round23up

public static long round23up(long x)

Round up to nearest power of two or three times a power of two.

Parameters:

x - The input value, which must be non-negative and not greater than 3 * 2⁶¹.

Returns:

x rounded up to the nearest power of two or three times a power of two.

sqrt4down

public static int sqrt4down(int x)

Square root rounded down to nearest power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

Square root of x rounded down to nearest power of two.

sqrt4down

public static long sqrt4down(long x)

Square root rounded down to nearest power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

Square root of x rounded down to nearest power of two.

sqrt4up

public static int sqrt4up(int x)

Square root rounded up to nearest power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

Square root of x rounded up to nearest power of two.

sqrt4up

public static long sqrt4up(long x)

Square root rounded up to nearest power of two.

Parameters:

x - The input value, which must be non-negative.

Returns:

Square root of x rounded up to nearest power of two.

log2down

public static int log2down(int x)

Base-2 logarithm rounded down to nearest power of two.

Parameters:

x - The input value, which must be positive.

Returns:

log2(x) rounded down to nearest integer.

log2down

public static int log2down(long x)

Base-2 logarithm rounded down to nearest power of two.

Parameters:

x - The input value, which must be positive.

Returns:

log2(x) rounded down to nearest integer.

log2up

public static int log2up(int x)

Base-2 logarithm rounded up to nearest power of two.

Parameters:

x - The input value, which must be positive.

Returns:

log2(x) rounded up to nearest integer.

log2up

public static int log2up(long x)

Base-2 logarithm rounded up to nearest power of two.

Parameters:

x - The input value, which must be positive.

Returns:

log2(x) rounded up to nearest integer.

ifFinite

public static long ifFinite(long x,
 long y)

Returns the argument y limited to Apfloat.INFINITE. In case x is Apfloat.INFINITE, then Apfloat.INFINITE is returned, otherwise y. Also if y is negative or zero, this is treated as a case of overflow, and Apfloat.INFINITE is returned. The return value is thus always positive.

Parameters:

x - The argument that is tested to be Apfloat.INFINITE.

y - The argument that is returned if x is not Apfloat.INFINITE.

Returns:

(x == Apfloat.INFINITE || y <= 0 ? Apfloat.INFINITE : y)

max

public static long max(long x,
 long... y)

Returns the maximum of the arguments.

Parameters:

x - The first argument.

y - More arguments.

Returns:

The maximum of the arguments

min

public static long min(long x,
 long... y)

Returns the minimum of the arguments.

Parameters:

x - The first argument.

y - More arguments.

Returns:

The minimum of the arguments

multiplyExact

public static long multiplyExact(long x,
 long y)
                          throws OverflowException

Returns the product of the arguments, throwing an exception if the result overflows a long.

Parameters:

x - The first operand.

y - The second operand.

Returns:

The result.

Throws:

OverflowException - If the result overflows a long

addExact

public static long addExact(long x,
 long y)
                     throws OverflowException

Returns the sum of the arguments, throwing an exception if the result overflows a long.

Parameters:

x - The first operand.

y - The second operand.

Returns:

The result.

Throws:

OverflowException - If the result overflows a long

subtractExact

public static long subtractExact(long x,
 long y)
                          throws OverflowException

Returns the difference of the arguments, throwing an exception if the result overflows a long.

Parameters:

x - The first operand.

y - The second operand.

Returns:

The result.

Throws:

OverflowException - If the result overflows a long

stream

public static <T> Stream<T> stream(Iterator<T> iterator)

Convert iterator to stream.

Type Parameters:

T - The type.

Parameters:

iterator - The iterator.

Returns:

The stream.

Since:

1.12.0