jsimple.util

Class IntegerUtil

java.lang.Object

jsimple.util.IntegerUtil

public final class IntegerUtil
extends java.lang.Object

The wrapper for the primitive type int.

As with the specification, this implementation relies on code laid out in Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002) as well as The Aggregate's Magic Algorithms.

Since:

1.1

See Also:

Number

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_RADIX The maximum radix used for conversions between characters and integers.
static int	MAX_VALUE Constant for the maximum int value, 231-1.
static int	MIN_RADIX The minimum radix used for conversions between characters and integers.
static int	MIN_VALUE Constant for the minimum int value, -231.

Constructor Summary

Constructors

Constructor and Description
IntegerUtil()

Method Summary

Modifier and Type	Method and Description
static int	bitCount(int i) Counts the number of 1 bits in the specified integer; this is also referred to as population count.
static int	decode(java.lang.String string) Parses the specified string and returns an int if the string can be decoded into an integer value.
static int	digit(char c, int radix) Determine the value of the specified character c in the supplied radix.
static int	highestOneBit(int i) Determines the highest (leftmost) bit of the specified integer that is 1 and returns the bit mask value for that bit.
static int	lowestOneBit(int i) Determines the lowest (rightmost) bit of the specified integer that is 1 and returns the bit mask value for that bit.
static int	numberOfLeadingZeros(int i) Determines the number of leading zeros in the specified integer prior to the highest one bit.
static int	numberOfTrailingZeros(int i) Determines the number of trailing zeros in the specified integer after the lowest one bit.
static int	parseInt(java.lang.String string) Parses the specified string as a signed decimal integer value.
static int	parseInt(java.lang.String string, int radix) Parses the specified string as a signed integer value using the specified radix.
static int	reverse(int i) Reverses the order of the bits of the specified integer.
static int	reverseBytes(int i) Reverses the order of the bytes of the specified integer.
static int	rotateLeft(int i, int distance) Rotates the bits of the specified integer to the left by the specified number of bits.
static int	rotateRight(int i, int distance) Rotates the bits of the specified integer to the right by the specified number of bits.
static java.lang.String	toBinaryString(int i) Converts the specified integer into its binary string representation.
static java.lang.String	toDecimalString(int value)
static java.lang.String	toHexString(int i) Converts the specified integer into its hexadecimal string representation.
static java.lang.String	toString(int value) Converts the specified integer into its decimal string representation.

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 int MAX_VALUE

Constant for the maximum int value, 2³¹-1.

See Also:

Constant Field Values

MIN_VALUE

public static final int MIN_VALUE

Constant for the minimum int value, -2³¹.

See Also:

Constant Field Values

MIN_RADIX

public static final int MIN_RADIX

The minimum radix used for conversions between characters and integers.

See Also:

Constant Field Values

MAX_RADIX

public static final int MAX_RADIX

The maximum radix used for conversions between characters and integers.

See Also:

Constant Field Values

Constructor Detail

IntegerUtil

public IntegerUtil()

Method Detail

decode

public static int decode(java.lang.String string)
                  throws InvalidFormatException

Parses the specified string and returns an int if the string can be decoded into an integer value. The string may be an optional minus sign "-" followed by a hexadecimal ("0x..." or "#..."), octal ("0..."), or decimal ("...") representation of an integer.

Parameters:

string - a string representation of an integer value.

Returns:

an int for the value represented by string

Throws:

InvalidFormatException - if string can not be parsed as an integer value

parseInt

public static int parseInt(java.lang.String string)
                    throws InvalidFormatException

Parses the specified string as a signed decimal integer value. The ASCII character - ('-') is recognized as the minus sign.

Parameters:

string - the string representation of an integer value.

Returns:

the primitive integer value represented by string.

Throws:

InvalidFormatException - if string cannot be parsed as an integer value.

parseInt

public static int parseInt(java.lang.String string,
                           int radix)
                    throws InvalidFormatException

Parses the specified string as a signed integer value using the specified radix. The ASCII character - ('-') is recognized as the minus sign.

Parameters:

string - the string representation of an integer value.

radix - the radix to use when parsing.

Returns:

the primitive integer value represented by string using radix.

Throws:

InvalidFormatException - if string is null or has a length of zero, radix < Character.MIN_RADIX, radix > Character.MAX_RADIX, or if string can not be parsed as an integer value.

toBinaryString

public static java.lang.String toBinaryString(int i)

Converts the specified integer into its binary string representation. The returned string is a concatenation of '0' and '1' characters.

Parameters:

i - the integer to convert.

Returns:

the binary string representation of i.

toHexString

public static java.lang.String toHexString(int i)

Converts the specified integer into its hexadecimal string representation. The returned string is a concatenation of characters from '0' to '9' and 'a' to 'f'.

Parameters:

i - the integer to convert.

Returns:

the hexadecimal string representation of i.

toDecimalString

public static java.lang.String toDecimalString(int value)

toString

public static java.lang.String toString(int value)

Converts the specified integer into its decimal string representation. The returned string is a concatenation of a minus sign if the number is negative and characters from '0' to '9'.

Parameters:

value - the integer to convert.

Returns:

the decimal string representation of value.

highestOneBit

public static int highestOneBit(int i)

Determines the highest (leftmost) bit of the specified integer that is 1 and returns the bit mask value for that bit. This is also referred to as the Most Significant 1 Bit. Returns zero if the specified integer is zero.

Parameters:

i - the integer to examine.

Returns:

the bit mask indicating the highest 1 bit in i.

Since:

1.5

lowestOneBit

public static int lowestOneBit(int i)

Determines the lowest (rightmost) bit of the specified integer that is 1 and returns the bit mask value for that bit. This is also referred to as the Least Significant 1 Bit. Returns zero if the specified integer is zero.

Parameters:

i - the integer to examine.

Returns:

the bit mask indicating the lowest 1 bit in i.

Since:

1.5

numberOfLeadingZeros

public static int numberOfLeadingZeros(int i)

Determines the number of leading zeros in the specified integer prior to the highest one bit.

Parameters:

i - the integer to examine.

Returns:

the number of leading zeros in i.

Since:

1.5

numberOfTrailingZeros

public static int numberOfTrailingZeros(int i)

Determines the number of trailing zeros in the specified integer after the lowest one bit.

Parameters:

i - the integer to examine.

Returns:

the number of trailing zeros in i.

Since:

1.5

bitCount

public static int bitCount(int i)

Counts the number of 1 bits in the specified integer; this is also referred to as population count.

Parameters:

i - the integer to examine.

Returns:

the number of 1 bits in i.

Since:

1.5

rotateLeft

public static int rotateLeft(int i,
                             int distance)

Rotates the bits of the specified integer to the left by the specified number of bits.

Parameters:

i - the integer value to rotate left.

distance - the number of bits to rotate.

Returns:

the rotated value.

Since:

1.5

rotateRight

public static int rotateRight(int i,
                              int distance)

Rotates the bits of the specified integer to the right by the specified number of bits.

Parameters:

i - the integer value to rotate right.

distance - the number of bits to rotate.

Returns:

the rotated value.

Since:

1.5

reverseBytes

public static int reverseBytes(int i)

Reverses the order of the bytes of the specified integer.

Parameters:

i - the integer value for which to reverse the byte order.

Returns:

the reversed value.

Since:

1.5

reverse

public static int reverse(int i)

Reverses the order of the bits of the specified integer.

Parameters:

i - the integer value for which to reverse the bit order.

Returns:

the reversed value.

Since:

1.5

digit

public static int digit(char c,
                        int radix)

Determine the value of the specified character c in the supplied radix. The value of radix must be between 2 and 36. If the character isn't a digit/letter or the value is outside the specified radix (e.g. it's an 'f' when the radix is 10) then an InvalidFormatException is thrown. Only ASCII characters (that is, Arabic number characters 0-9 and letters a-z / A-Z) are supported.

Parameters:

c - the character to determine the value of.

radix - the radix.

Returns:

the value of c in radix if radix lies between MIN_RADIX and MAX_RADIX

Throws:

InvalidFormatException - if character isn't digit/letter or returned value would be outside specified radix