com.cloudhopper.commons.util

Class ByteUtil

java.lang.Object

com.cloudhopper.commons.util.ByteUtil

public class ByteUtil
extends Object

Utility class for methods to handle bytes.

Author:

joelauer (twitter: @jjlauer or http://twitter.com/jjlauer)

Constructor Summary

Constructors

Constructor and Description
ByteUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static String	decodeBcd(byte[] data, int offset, int len) BCD decodes a byte array into a String.
static byte[]	decodeHex(String hexString, int width) Deprecated. Please see class HexUtil
static short	decodeUnsigned(byte signed) Allow a variable of type byte to carry lengths or sizes up to 255.
static byte[]	encodeBcd(String data, int num_bytes) BCD encodes a String into a byte array.
static String	encodeHex(byte value) Deprecated. Please see class HexUtil
static String	encodeHex(byte[] bytes) Deprecated. Please see class HexUtil
static String	encodeHex(byte[] data, char delimiter) Deprecated. Please see class HexUtil
static String	padLeading(String data, int width)

Methods inherited from class java.lang.Object

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

Constructor Detail

ByteUtil

public ByteUtil()

Method Detail

encodeBcd

public static byte[] encodeBcd(String data,
               int num_bytes)

BCD encodes a String into a byte array.

decodeBcd

public static String decodeBcd(byte[] data,
               int offset,
               int len)

BCD decodes a byte array into a String. For example, addresses inside PDUs for SMS are usually BCD encoded. An address of "13134434272" will actually look like this inside the byte[] "31314443722F" len is the number of bytes to read.

decodeHex

@Deprecated
public static byte[] decodeHex(String hexString,
                          int width)

Deprecated. Please see class HexUtil

Decodes the string data (in hex) into a byte array.

Parameters:

width - The width of the hex encoding (2 or 4)

encodeHex

@Deprecated
public static String encodeHex(byte value)

Deprecated. Please see class HexUtil

Encodes a byte into a hex string (hex dump).

encodeHex

@Deprecated
public static String encodeHex(byte[] bytes)

Deprecated. Please see class HexUtil

Encodes a byte array into a hex string (hex dump).

encodeHex

@Deprecated
public static String encodeHex(byte[] data,
                          char delimiter)

Deprecated. Please see class HexUtil

Encodes a byte array into a hex string (hex dump).

padLeading

public static String padLeading(String data,
                int width)

decodeUnsigned

public static short decodeUnsigned(byte signed)

Allow a variable of type byte to carry lengths or sizes up to 255. The integral types are signed in Java, so if there is necessary to store an unsigned type into signed of the same size, the value can be stored as negative number even if it would be positive in unsigned case. For example message length can be 0 to 254 and is carried by 1 octet i.e. unsigned 8 bits. We use a byte variable to read the value from octet stream. If the length is >127, it is interpreted as negative byte using negative complement notation. So length 150 would be interpreted as Java byte -106. If we want to know the actual value (*length) we need to make a correction to a bigger integral type, in case of byte it's short. The correction from (negative) byte to short is
(short)(256+(short)length)
This converts the negative byte value representing positive length into positive short value.

See Also:

#encodeUnsigned(short)