net.rim.device.api.util
Class CRC16

java.lang.Object
  net.rim.device.api.util.CRC16

public final class CRC16
extends Object

Computes the 16-bit CRC (checksum) for a data stream.

Based on FCS-16 specified in RFC 1662 (STD 51).

Note: The byte ordering of the resulting checksum value depends on the protocol in which the CRC is used. The ordering used in a specified protocol might be different from the ordering used in this implementation. The output of this implementation can be reversed when used with such a protocol.

Field Summary
static int	INITIAL_VALUE Initial checksum value used before updates.

Method Summary
static int	update(int crc, byte[] b) Updates the checksum with the specified array of bytes.
static int	update(int crc, byte[] b, int offset, int length) Updates the checksum with a section of provided array of bytes.
static int	update(int crc, int b) Updates the checksum with the specified byte.

Methods inherited from class java.lang.Object

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

Field Detail

INITIAL_VALUE

public static final int INITIAL_VALUE

Initial checksum value used before updates.

See Also:

Constant Field Values

Method Detail

update

public static int update(int crc,
                         int b)

Updates the checksum with the specified byte.

Parameters:

crc - The checksum to update.

b - The byte with which to update the checksum.

Returns:

Resulting checksum value.

update

public static int update(int crc,
                         byte[] b)

Updates the checksum with the specified array of bytes.

Parameters:

crc - The checksum to update.

b - The byte array with which to update the checksum.

Returns:

Resulting checksum value.

update

public static int update(int crc,
                         byte[] b,
                         int offset,
                         int length)

Updates the checksum with a section of provided array of bytes.

Parameters:

crc - The checksum to update.

b - The byte array containing the section with which to update the checksum.

off - The first element in the byte array used to update the checksum.

len - The number of bytes in the section used to update the checksum.

Returns:

Resulting checksum value.