lava.util
Class BitTwiddler

java.lang.Object
  |
  +--lava.util.BitTwiddler

public class BitTwiddler

extends java.lang.Object

Bit-twiddling operations.

BitTwiddler is a collection of static methods that perform bit-twiddling operations.

Version:

1999.08.08

Constructor Summary

BitTwiddler()

Method Summary

static java.lang.String	bitString(int value, int blocksize) Represents an int in binary notation as a string of zeros and ones.
static int	countSetBits(byte b) Counts set bits.
static int	countSetBits(int i) Counts set bits.
static int	countSetBits(long l) Counts set bits.
static int	countSetBits(short s) Counts set bits.
static int	mostSignificant(int integer, boolean value) Searches for a bit value in an int.
static int	reverseBits(int i) Reverses order of bits in ing.
static long	reverseBits(long l) Reverses order of bits in long.
static int	reverseEndian(int i) Reverses endianness of int.
static long	reverseEndian(long l) Reverses endianness of long.
static short	reverseEndian(short s) Reverses endianness of short.
static byte[]	toBytesBe(int i, byte[] dest, int offset) Breaks int into big endian bytes.
static byte[]	toBytesBe(long l, byte[] dest, int offset) Breaks long into big endian bytes.
static byte[]	toBytesBe(short s, byte[] dest, int offset) Breaks short into big endian bytes.
static byte[]	toBytesLe(int i, byte[] dest, int offset) Breaks int into little endian bytes.
static byte[]	toBytesLe(long l, byte[] dest, int offset) Breaks long into little endian bytes.
static byte[]	toBytesLe(short s, byte[] dest, int offset) Breaks short into little endian bytes.
static int	toIntBe(byte[] b) Shorthand for toIntBe (b, 0).
static int	toIntBe(byte[] b, int offset) Converts big endian bytes into int.
static int	toIntLe(byte[] b) Shorthand for toIntLe (b, 0).
static int	toIntLe(byte[] b, int offset) Converts little endian bytes into int.
static long	toLongBe(byte[] b) Shorthand for toLongBe (b, 0).
static long	toLongBe(byte[] b, int offset) Converts big endian bytes into long.
static long	toLongLe(byte[] b) Shorthand for toLongLe (b, 0).
static long	toLongLe(byte[] b, int offset) Converts little endian bytes into long.
static short	toShortBe(byte[] b) Shorthand for toShortBe (b, 0).
static short	toShortBe(byte[] b, int offset) Converts big endian bytes into short.
static short	toShortLe(byte[] b) Shorthand for toShortLe (b, 0).
static short	toShortLe(byte[] b, int offset) Converts little endian bytes into short.

Methods inherited from class java.lang.Object

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

Constructor Detail

BitTwiddler

public BitTwiddler()

Method Detail

toLongBe

public static final long toLongBe(byte[] b,
                                  int offset)

Converts big endian bytes into long.

Details: This method converts big endian ordered bytes into a long. offset is the array index of the first byte.

Parameters:

b - the byte array

the - array offset (default value: 0)

Returns:

the long

Since:

1999.08.01

toLongBe

public static final long toLongBe(byte[] b)

Shorthand for toLongBe (b, 0).

Since:

1998.11.19

See Also:

toLongBe(byte[], int)

toLongLe

public static final long toLongLe(byte[] b,
                                  int offset)

Converts little endian bytes into long.

Details: This method converts little endian ordered bytes into a long. offset is the array index of the first byte.

Parameters:

b - the byte array

the - array offset (default value: 0)

Returns:

the long

Since:

1999.08.01

toLongLe

public static final long toLongLe(byte[] b)

Shorthand for toLongLe (b, 0).

Since:

1998.11.19

See Also:

toLongLe(byte[], int)

toIntBe

public static final int toIntBe(byte[] b,
                                int offset)

Converts big endian bytes into int.

Details: This method converts big endian ordered bytes into an int. offset is the array index of the first byte.

Parameters:

b - the byte array

the - array offset (default value: 0)

Returns:

the int

Since:

1999.08.01

toIntBe

public static final int toIntBe(byte[] b)

Shorthand for toIntBe (b, 0).

Since:

1998.11.19

See Also:

toIntBe(byte[], int)

toIntLe

public static final int toIntLe(byte[] b,
                                int offset)

Converts little endian bytes into int.

Details: This method converts little endian ordered bytes into an int. offset is the array index of the first byte.

Parameters:

b - the byte array

the - array offset (default value: 0)

Returns:

the int

Since:

1999.08.01

toIntLe

public static final int toIntLe(byte[] b)

Shorthand for toIntLe (b, 0).

Since:

1998.11.19

See Also:

toIntLe(byte[], int)

toShortBe

public static final short toShortBe(byte[] b,
                                    int offset)

Converts big endian bytes into short.

Details: This method converts big endian ordered bytes into a short. offset is the array index of the first byte.

Parameters:

b - the byte array

the - array offset (default value: 0)

Returns:

the short

Since:

1999.08.01

toShortBe

public static final short toShortBe(byte[] b)

Shorthand for toShortBe (b, 0).

Since:

1998.11.19

See Also:

toShortBe(byte[], int)

toShortLe

public static final short toShortLe(byte[] b,
                                    int offset)

Converts little endian bytes into short.

Details: This method converts little endian ordered bytes into a short. offset is the array index of the first byte.

Parameters:

b - the byte array

the - array offset (default value: 0)

Returns:

the short

Since:

1999.08.01

toShortLe

public static final short toShortLe(byte[] b)

Shorthand for toShortLe (b, 0).

Since:

1998.11.19

See Also:

toShortLe(byte[], int)

toBytesBe

public static final byte[] toBytesBe(long l,
                                     byte[] dest,
                                     int offset)

Breaks long into big endian bytes.

Details: This method breaks a long into 8 bytes and stores them in the given array, at the given index, using big endian byte ordering.

Parameters:

l - the long

dest - the destination array

offset - the array index

Returns:

dest

toBytesLe

public static final byte[] toBytesLe(long l,
                                     byte[] dest,
                                     int offset)

Breaks long into little endian bytes.

Details: This method breaks a long into 8 bytes and stores them in the given array, at the given index, using little endian byte ordering.

Parameters:

l - the long

dest - the destination array

offset - the array index

Returns:

dest

toBytesBe

public static final byte[] toBytesBe(int i,
                                     byte[] dest,
                                     int offset)

Breaks int into big endian bytes.

Details: This method breaks an int into 4 bytes and stores them in the given array, at the given index, using big endian byte ordering.

Parameters:

i - the int

dest - the destination array

offset - the array index

Returns:

dest

toBytesLe

public static final byte[] toBytesLe(int i,
                                     byte[] dest,
                                     int offset)

Breaks int into little endian bytes.

Details: This method breaks an int into 4 bytes and stores them in the given array, at the given index, using little endian byte ordering.

Parameters:

i - the int

dest - the destination array

offset - the array index

Returns:

dest

toBytesBe

public static final byte[] toBytesBe(short s,
                                     byte[] dest,
                                     int offset)

Breaks short into big endian bytes.

Details: This method breaks a short into 2 bytes and stores them in the given array, at the given index, using big endian byte ordering.

Parameters:

s - the short

dest - the destination array

offset - the array index

Returns:

dest

toBytesLe

public static final byte[] toBytesLe(short s,
                                     byte[] dest,
                                     int offset)

Breaks short into little endian bytes.

Details: This method breaks a short into 2 bytes and stores them in the given array, at the given index, using little endian byte ordering.

Parameters:

s - the short

dest - the destination array

offset - the array index

Returns:

dest

reverseEndian

public static final long reverseEndian(long l)

Reverses endianness of long.

Parameters:

l - the long

Returns:

the reversed long

reverseEndian

public static final int reverseEndian(int i)

Reverses endianness of int.

Parameters:

i - the int

Returns:

the reversed int

reverseEndian

public static final short reverseEndian(short s)

Reverses endianness of short.

Parameters:

s - the short

Returns:

the reversed short

reverseBits

public static final long reverseBits(long l)

Reverses order of bits in long.

Parameters:

l - the long

Returns:

the reversed long

reverseBits

public static final int reverseBits(int i)

Reverses order of bits in ing.

Parameters:

i - the int

Returns:

the reversed int

bitString

public static java.lang.String bitString(int value,
                                         int blocksize)

Represents an int in binary notation as a string of zeros and ones. The binary string may be broken up into blocks of digits to increase readability.

Parameters:

value - the value to represent

blocksize - the number digits per block

Returns:

a binary representation of value

mostSignificant

public static final int mostSignificant(int integer,
                                        boolean value)

Searches for a bit value in an int. Returns the position of the most significant bit matching the given value, or -1 if the bit value does not occur at all in integer.

Parameters:

integer - the int

Returns:

the position

countSetBits

public static final int countSetBits(long l)

Counts set bits.

Details: This method returns the number of bits in l that are 1.

Parameters:

l - a long

Returns:

the count

Since:

1999.08.08

countSetBits

public static final int countSetBits(int i)

Counts set bits.

Details: This method returns the number of bits in i that are 1.

Parameters:

i - an int

Returns:

the count

Since:

1999.08.08

countSetBits

public static final int countSetBits(short s)

Counts set bits.

Details: This method returns the number of bits in s that are 1.

Parameters:

s - a short

Returns:

the count

Since:

1999.08.08

countSetBits

public static final int countSetBits(byte b)

Counts set bits.

Details: This method returns the number of bits in b that are 1.

Parameters:

b - a byte

Returns:

the count

Since:

1999.08.08