com.google.common.primitives

Class UnsignedLongs

java.lang.Object

com.google.common.primitives.UnsignedLongs

@Beta
@GwtCompatible
public final class UnsignedLongs
extends Object

Static utility methods pertaining to long primitives that interpret values as unsigned (that is, any negative value x is treated as the positive value 2^64 + x). The methods for which signedness is not an issue are in Longs, as well as signed versions of methods for which signedness is an issue.

In addition, this class provides several static methods for converting a long to a String and a String to a long that treat the long as an unsigned number.

Users of these utilities must be extremely careful not to mix up signed and unsigned long values. When possible, it is recommended that the UnsignedLong wrapper class be used, at a small efficiency penalty, to enforce the distinction in the type system.

See the Guava User Guide article on unsigned primitive utilities.

Since:

10.0

Author:

Louis Wasserman, Brian Milch, Colin Evans

Field Summary

Fields

Modifier and Type	Field and Description
static long	MAX_VALUE

Method Summary

Methods

Modifier and Type	Method and Description
static int	compare(long a, long b) Compares the two specified long values, treating them as unsigned values between 0 and 2^64 - 1 inclusive.
static long	decode(String stringValue) Returns the unsigned long value represented by the given string.
static long	divide(long dividend, long divisor) Returns dividend / divisor, where the dividend and divisor are treated as unsigned 64-bit quantities.
static String	join(String separator, long... array) Returns a string containing the supplied unsigned long values separated by separator.
static Comparator<long[]>	lexicographicalComparator() Returns a comparator that compares two arrays of unsigned long values lexicographically.
static long	max(long... array) Returns the greatest value present in array, treating values as unsigned.
static long	min(long... array) Returns the least value present in array, treating values as unsigned.
static long	parseUnsignedLong(String s) Returns the unsigned long value represented by the given decimal string.
static long	parseUnsignedLong(String s, int radix) Returns the unsigned long value represented by a string with the given radix.
static long	remainder(long dividend, long divisor) Returns dividend % divisor, where the dividend and divisor are treated as unsigned 64-bit quantities.
static String	toString(long x) Returns a string representation of x, where x is treated as unsigned.
static String	toString(long x, int radix) Returns a string representation of x for the given radix, where x is treated as unsigned.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_VALUE

public static final long MAX_VALUE

See Also:

Constant Field Values

Method Detail

compare

public static int compare(long a,
          long b)

Compares the two specified long values, treating them as unsigned values between 0 and 2^64 - 1 inclusive.

Parameters:

a - the first unsigned long to compare

b - the second unsigned long to compare

Returns:

a negative value if a is less than b; a positive value if a is greater than b; or zero if they are equal

min

public static long min(long... array)

Returns the least value present in array, treating values as unsigned.

Parameters:

array - a nonempty array of unsigned long values

Returns:

the value present in array that is less than or equal to every other value in the array according to compare(long, long)

Throws:

IllegalArgumentException - if array is empty

max

public static long max(long... array)

Returns the greatest value present in array, treating values as unsigned.

Parameters:

array - a nonempty array of unsigned long values

Returns:

the value present in array that is greater than or equal to every other value in the array according to compare(long, long)

Throws:

IllegalArgumentException - if array is empty

join

public static String join(String separator,
          long... array)

Returns a string containing the supplied unsigned long values separated by separator. For example, join("-", 1, 2, 3) returns the string "1-2-3".

Parameters:

separator - the text that should appear between consecutive values in the resulting string (but not at the start or end)

array - an array of unsigned long values, possibly empty

lexicographicalComparator

public static Comparator<long[]> lexicographicalComparator()

Returns a comparator that compares two arrays of unsigned long values lexicographically. That is, it compares, using compare(long, long)), the first pair of values that follow any common prefix, or when one array is a prefix of the other, treats the shorter array as the lesser. For example, [] < [1L] < [1L, 2L] < [2L] < [1L << 63].

The returned comparator is inconsistent with Object.equals(Object) (since arrays support only identity equality), but it is consistent with Arrays.equals(long[], long[]).

See Also:

Lexicographical order article at Wikipedia

divide

public static long divide(long dividend,
          long divisor)

Returns dividend / divisor, where the dividend and divisor are treated as unsigned 64-bit quantities.

Parameters:

dividend - the dividend (numerator)

divisor - the divisor (denominator)

Throws:

ArithmeticException - if divisor is 0

remainder

public static long remainder(long dividend,
             long divisor)

Returns dividend % divisor, where the dividend and divisor are treated as unsigned 64-bit quantities.

Parameters:

dividend - the dividend (numerator)

divisor - the divisor (denominator)

Throws:

ArithmeticException - if divisor is 0

Since:

11.0

parseUnsignedLong

public static long parseUnsignedLong(String s)

Returns the unsigned long value represented by the given decimal string.

Throws:

NumberFormatException - if the string does not contain a valid unsigned long value

NullPointerException - if s is null (in contrast to Long.parseLong(String))

decode

public static long decode(String stringValue)

Returns the unsigned long value represented by the given string. Accepts a decimal, hexadecimal, or octal number given by specifying the following prefix:

• 0xHexDigits
• 0XHexDigits
• #HexDigits
• 0OctalDigits

Throws:

NumberFormatException - if the string does not contain a valid unsigned long value

Since:

13.0

parseUnsignedLong

public static long parseUnsignedLong(String s,
                     int radix)

Returns the unsigned long value represented by a string with the given radix.

Parameters:

s - the string containing the unsigned long representation to be parsed.

radix - the radix to use while parsing s

Throws:

NumberFormatException - if the string does not contain a valid unsigned long with the given radix, or if radix is not between Character.MIN_RADIX and Character.MAX_RADIX.

NullPointerException - if s is null (in contrast to Long.parseLong(String))

toString

public static String toString(long x)

Returns a string representation of x, where x is treated as unsigned.

toString

public static String toString(long x,
              int radix)

Returns a string representation of x for the given radix, where x is treated as unsigned.

Parameters:

x - the value to convert to a string.

radix - the radix to use while working with x

Throws:

IllegalArgumentException - if radix is not between Character.MIN_RADIX and Character.MAX_RADIX.