org.eigenbase.util
Class BitString

java.lang.Object
  org.eigenbase.util.BitString

public class BitString
extends Object

String of bits.

A bit string logically consists of a set of '0' and '1' values, of a specified length. The length is preserved even if this means that the bit string has leading '0's.

You can create a bit string from a string of 0s and 1s (BitString(String,int) or createFromBitString(java.lang.String)), or from a string of hex digits (createFromHexString(java.lang.String)). You can convert it to a byte array (getAsByteArray()), to a bit string (toBitString()), or to a hex string (toHexString()). A utility method toByteArrayFromBitString(java.lang.String, int) converts a bit string directly to a byte array.

This class is immutable: once created, none of the methods modify the value.

Since:

May 28, 2004

Version:

$Id: //open/dev/farrago/src/org/eigenbase/util/BitString.java#12 $

Author:

Wael Chatila

"JUnit testcase:"

Field Summary

private int	bitCount
private String	bits
private static char[]	Hexits

Constructor Summary

protected

BitString(String bits, int bitCount)

Method Summary

static BitString	concat(BitString[] args) Concatenates some BitStrings.
static BitString	createFromBitString(String s) Creates a BitString representation out of a Bit String.
static BitString	createFromBytes(byte[] bytes) Creates a BitString from an array of bytes.
static BitString	createFromHexString(String s) Creates a BitString representation out of a Hex String.
byte[]	getAsByteArray()
int	getBitCount()
String	toBitString() Returns this bit string as a bit string, such as "10110".
static byte[]	toByteArrayFromBitString(String bits, int bitCount) Converts a bit string to an array of bytes.
String	toHexString() Converts this bit string to a hex string, such as "7AB".
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

Hexits

private static final char[] Hexits

bits

private String bits

bitCount

private int bitCount

Constructor Detail

BitString

protected BitString(String bits,
                    int bitCount)

Method Detail

createFromHexString

public static BitString createFromHexString(String s)

Creates a BitString representation out of a Hex String. Initial zeros are be preserved. Hex String is defined in the SQL standard to be a string with odd number of hex digits. An even number of hex digits is in the standard a Binary String.

Parameters:

s - a string, in hex notation

Throws:

NumberFormatException - if s is invalid.

createFromBitString

public static BitString createFromBitString(String s)

Creates a BitString representation out of a Bit String. Initial zeros are be preserved.

Parameters:

s - a string of 0s and 1s.

Throws:

NumberFormatException - if s is invalid.

toString

public String toString()

Overrides:

toString in class Object

getBitCount

public int getBitCount()

getAsByteArray

public byte[] getAsByteArray()

toBitString

public String toBitString()

Returns this bit string as a bit string, such as "10110".

toHexString

public String toHexString()

Converts this bit string to a hex string, such as "7AB".

toByteArrayFromBitString

public static byte[] toByteArrayFromBitString(String bits,
                                              int bitCount)

Converts a bit string to an array of bytes.

"Postcondition:"

return.length = (bitCount + 7) / 8

concat

public static BitString concat(BitString[] args)

Concatenates some BitStrings. Concatenates all at once, not pairwise, to avoid string copies.

Parameters:

args - BitString[]

createFromBytes

public static BitString createFromBytes(byte[] bytes)

Creates a BitString from an array of bytes.

Parameters:

bytes - Bytes

Returns:

BitString