io.netty.util.internal

Class MathUtil

java.lang.Object

io.netty.util.internal.MathUtil

public final class MathUtil
extends Object

Math utility methods.

Method Summary

Modifier and Type	Method and Description
static int	compare(int x, int y) Compares two int values.
static int	compare(long x, long y) Compare two long values.
static int	findNextPositivePowerOfTwo(int value) Fast method of finding the next power of 2 greater than or equal to the supplied value.
static boolean	isOutOfBounds(int index, int length, int capacity) Determine if the requested index and length will fit within capacity.
static int	safeFindNextPositivePowerOfTwo(int value) Fast method of finding the next power of 2 greater than or equal to the supplied value.

Methods inherited from class java.lang.Object

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

Method Detail

findNextPositivePowerOfTwo

public static int findNextPositivePowerOfTwo(int value)

Fast method of finding the next power of 2 greater than or equal to the supplied value.

If the value is <= 0 then 1 will be returned. This method is not suitable for Integer.MIN_VALUE or numbers greater than 2^30.

Parameters:

value - from which to search for next power of 2

Returns:

The next power of 2 or the value itself if it is a power of 2

safeFindNextPositivePowerOfTwo

public static int safeFindNextPositivePowerOfTwo(int value)

Fast method of finding the next power of 2 greater than or equal to the supplied value.

This method will do runtime bounds checking and call findNextPositivePowerOfTwo(int) if within a valid range.

Parameters:

value - from which to search for next power of 2

Returns:

The next power of 2 or the value itself if it is a power of 2.

Special cases for return values are as follows:

• <= 0 -> 1
• >= 2^30 -> 2^30

isOutOfBounds

public static boolean isOutOfBounds(int index,
                                    int length,
                                    int capacity)

Determine if the requested index and length will fit within capacity.

Parameters:

index - The starting index.

length - The length which will be utilized (starting from index).

capacity - The capacity that index + length is allowed to be within.

Returns:

false if the requested index and length will fit within capacity. true if this would result in an index out of bounds exception.

compare

public static int compare(int x,
                          int y)

Compares two int values.

Parameters:

x - the first int to compare

y - the second int to compare

Returns:

the value 0 if x == y; -1 if x < y; and 1 if x > y

compare

public static int compare(long x,
                          long y)

Compare two long values.

Parameters:

x - the first long to compare.

y - the second long to compare.

Returns:

• 0 if x == y
• > 0 if x > y
• < 0 if x < y