public
class
MathUtil
extends Object| java.lang.Object | |
| ↳ | com.pnfsoftware.jeb.util.math.MathUtil |
Class Overview
Set of common operations on Number that are not in Math.
Summary
| Public Constructors | |||||||||||
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| MathUtil() | |||||||||||
| Public Methods | |||||||||||
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| static boolean |
almostEquals(double a, double b)
Check for almost equality: tolerate a 1e-7 gap to make up for numerical errors inherent to
IEEE754 calculations.
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| static boolean |
almostEquals(double a, double b, double epsilon)
Check for almost equality: tolerate an epsilon gap to make up for numerical errors inherent
to IEEE754 calculations.
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| static double | avg(byte[] array) | ||||||||||
| static double | avg(float[] array) | ||||||||||
| static double | avg(char[] array) | ||||||||||
| static double | avg(short[] array) | ||||||||||
| static double | avg(int[] array) | ||||||||||
| static double | avg(long[] array) | ||||||||||
| static double | avg(Collection<? extends Number> collection) | ||||||||||
| static double | avg(double[] array) | ||||||||||
| static boolean |
betweenExclusive(long value, long min, long max)
Check that a value is between two bounds (exclusive)
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| static boolean |
betweenInclusive(long value, long min, long max)
Check that a value is between two bounds (inclusive)
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| static int | bitcount(int value) | ||||||||||
| static int | bitcount(long value) | ||||||||||
| static boolean |
isPowerOfTwo(long n)
Determine is a strictly positive integer is a power of 2.
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| static boolean |
isPowerOfTwo(int n)
Determine is a strictly positive integer is a power of 2.
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| static int |
log2(int n)
Get the truncated base2 log of the input.
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| static int |
log2(long n)
Get the truncated base2 log of the input.
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| static long |
makeInverseMask(int bitsize)
Create a 64-bit inverse mask.
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| static long |
makeMask(int bitsize)
Create a 64-bit mask.
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| static long |
makeOverflow(int bitsize)
Create a 64-bit overflow.
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| static int |
minPositive(int... values)
Get the min of the values which is > 0.
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| static int |
moduloPositive(int a, int b)
Calculate the positive remainder of two integers.
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| static int | msb(long value, int bitsize) | ||||||||||
| static long |
pow(long a, long b)
Long int exponentiation.
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| static int |
pow(int a, int b)
Integer exponentiation.
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| static long | signExtend(long value, int bitsize) | ||||||||||
| static long | signExtend32(long value, int bitsize) | ||||||||||
| static int | signExtend32(int value, int bitsize) | ||||||||||
| static long | unmaskedArithShiftRight(long v, int cnt) | ||||||||||
| static long | unmaskedShiftLeft(long v, int cnt) | ||||||||||
| static long | unmaskedShiftRight(long v, int cnt) | ||||||||||
| static long | zeroExtend(long value, int bitsize) | ||||||||||
| static long | zeroExtend32(long value, int bitsize) | ||||||||||
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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Public Constructors
public MathUtil ()
Public Methods
public static boolean almostEquals (double a, double b)
Check for almost equality: tolerate a 1e-7 gap to make up for numerical errors inherent to IEEE754 calculations.
Returns
- true if |a-b|<=1e-7
public static boolean almostEquals (double a, double b, double epsilon)
Check for almost equality: tolerate an epsilon gap to make up for numerical errors inherent to IEEE754 calculations.
Parameters
| epsilon | a positive number |
|---|
Returns
- true if |a-b|<=epsilon
public static double avg (byte[] array)
public static double avg (float[] array)
public static double avg (char[] array)
public static double avg (short[] array)
public static double avg (int[] array)
public static double avg (long[] array)
public static double avg (Collection<? extends Number> collection)
public static double avg (double[] array)
public static boolean betweenExclusive (long value, long min, long max)
Check that a value is between two bounds (exclusive)
Parameters
| value | value |
|---|---|
| min | min bound |
| max | max bound |
Returns
- true if when value is in range ]min, max[
public static boolean betweenInclusive (long value, long min, long max)
Check that a value is between two bounds (inclusive)
Parameters
| value | value |
|---|---|
| min | min bound |
| max | max bound |
Returns
- true if when value is in range [min, max]
public static int bitcount (int value)
public static int bitcount (long value)
public static boolean isPowerOfTwo (long n)
Determine is a strictly positive integer is a power of 2.
Parameters
| n | a positive integer |
|---|
public static boolean isPowerOfTwo (int n)
Determine is a strictly positive integer is a power of 2.
Parameters
| n | a positive integer |
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public static int log2 (int n)
Get the truncated base2 log of the input.
Parameters
| n | must be strictly positive |
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public static int log2 (long n)
Get the truncated base2 log of the input.
Parameters
| n | must be strictly positive |
|---|
public static long makeInverseMask (int bitsize)
Create a 64-bit inverse mask. Safe replacement for ~((ONE << BITSIZE) - ONE)
constructs.
Parameters
| bitsize | bitsize [0, 64] |
|---|
Returns
- the inverse mask
Throws
| IllegalArgumentException | if the bitsize is OOR |
|---|
public static long makeMask (int bitsize)
Create a 64-bit mask. Safe replacement for (ONE << BITSIZE) - ONE constructs.
Parameters
| bitsize | bitsize [0, 64] |
|---|
Returns
- the mask
Throws
| IllegalArgumentException | if the bitsize is OOR |
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public static long makeOverflow (int bitsize)
Create a 64-bit overflow. Safe replacement for (ONE << BITSIZE) constructs.
Parameters
| bitsize | bitsize [0, 64] |
|---|
Returns
- the overflow
Throws
| IllegalArgumentException | if the bitsize is OOR |
|---|
public static int minPositive (int... values)
Get the min of the values which is > 0. (for example when looking for min indexOf)
public static int moduloPositive (int a, int b)
Calculate the positive remainder of two integers.
Note: Java standard modulo operators specifies that the remainder will have the sign of the numerator. This method provides an alternate way to calculate the remainder, often-time more useful, by making sure that it remains positive.
Parameters
| a | any integer |
|---|---|
| b | a strictly positive integer |
Returns
- positive remainder
public static int msb (long value, int bitsize)
Parameters
| bitsize | must be in [0, 64] |
|---|
public static long pow (long a, long b)
Long int exponentiation.
Returns
- a**b (may have overflowed)
public static int pow (int a, int b)
Integer exponentiation.
Returns
- a**b (may have overflowed)
public static long signExtend (long value, int bitsize)
Parameters
| bitsize | must be in [0, 64] |
|---|
public static long signExtend32 (long value, int bitsize)
Parameters
| bitsize | must be in [0, 32] |
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public static int signExtend32 (int value, int bitsize)
Parameters
| bitsize | must be in [0, 32] |
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public static long unmaskedArithShiftRight (long v, int cnt)
public static long unmaskedShiftLeft (long v, int cnt)
public static long unmaskedShiftRight (long v, int cnt)
public static long zeroExtend (long value, int bitsize)
Parameters
| bitsize | must be in [0, 64] |
|---|
public static long zeroExtend32 (long value, int bitsize)
Parameters
| bitsize | must be in [0, 32] |
|---|