Package javacardx.framework.math

Class BCDUtil

java.lang.Object

javacardx.framework.math.BCDUtil

public final class BCDUtil
extends Object

The BCDUtil class contains common BCD(binary coded decimal) related utility functions. This class supports Packed BCD format. All methods in this class are static.

The BCDUtil class only supports unsigned numbers whose value can are represented in hexadecimal format using an implementation specific maximum number of bytes.

Since:

2.2.2

Constructor Summary

Constructors

Constructor	Description
BCDUtil()	Intended to be package visible.

Method Summary

Modifier and Type	Method	Description
static short	convertToBCD(byte[] hexArray, short bOff, short bLen, byte[] bcdArray, short outOff)	Converts the input hexadecimal data into BCD format.
static short	convertToHex(byte[] bcdArray, short bOff, short bLen, byte[] hexArray, short outOff)	Converts the input BCD data into hexadecimal format.
static short	getMaxBytesSupported()	This method returns the largest value that can be used with the BCD utility functions.
static boolean	isBCDFormat(byte[] bcdArray, short bOff, short bLen)	Checks if the input data is in BCD format.

Methods inherited from class java.lang.Object

equals

Constructor Detail

BCDUtil

public BCDUtil()

Intended to be package visible. Retain for compatibility

Method Detail

getMaxBytesSupported

public static short getMaxBytesSupported()

This method returns the largest value that can be used with the BCD utility functions. This number represents the byte length of the largest value in hex byte representation. All implementations must support at least 8 byte length usage capacity.

Returns:

the byte length of the largest hex value supported

convertToHex

public static short convertToHex(byte[] bcdArray,
                                 short bOff,
                                 short bLen,
                                 byte[] hexArray,
                                 short outOff)

Converts the input BCD data into hexadecimal format.

Note:

• If bOff or bLen or outOff parameter is negative an ArrayIndexOutOfBoundsException exception is thrown.
• If bOff+bLen is greater than bcdArray.length, the length of the bcdArray array a ArrayIndexOutOfBoundsException exception is thrown and no conversion is performed.
• If the output bytes need to be written at an offset greater than hexArray.length, the length of the hexArray array an ArrayIndexOutOfBoundsException exception is thrown and no conversion is performed.
• If bcdArray or hexArray parameter is null a NullPointerException exception is thrown.
• If the bcdArray and hexArray arguments refer to the same array object, or if any of these arguments refer to an array view sharing components with the other argument, then the conversion is performed as if the components at positions bOff through bOff+bLen-1 were first copied to a temporary array with bLen components and then the contents of the temporary array were converted into positions outOff onwards for the converted bytes of the output array.

Parameters:

bcdArray - input byte array

bOff - offset within byte array containing first byte (the high order byte)

bLen - byte length of input BCD data

hexArray - output byte array

outOff - offset within hexArray where output data begins

Returns:

the byte length of the output hexadecimal data

Throws:

ArrayIndexOutOfBoundsException - if converting would cause access of data outside array bounds or if bLen is negative

NullPointerException - if either bcdArray or hexArray is null

ArithmeticException - for the following conditions:

• if the input byte array format is not a correctly formed BCD value
• the size of the BCD value requires greater than supported maximum number of bytes to represent in hex format
• if bLen is 0

convertToBCD

public static short convertToBCD(byte[] hexArray,
                                 short bOff,
                                 short bLen,
                                 byte[] bcdArray,
                                 short outOff)

Converts the input hexadecimal data into BCD format. The output data is right justified. If the number of output BCD nibbles is odd, the first BCD nibble written is 0.

Note:

• If bOff or bLen or outOff parameter is negative an ArrayIndexOutOfBoundsException exception is thrown.
• If bOff+bLen is greater than hexArray.length, the length of the hexArray array a ArrayIndexOutOfBoundsException exception is thrown and no conversion is performed.
• If the output bytes need to be written at an offset greater than bcdArray.length, the length of the bcdArray array an ArrayIndexOutOfBoundsException exception is thrown and no conversion is performed.
• If bcdArray or hexArray parameter is null a NullPointerException exception is thrown.
• If the bcdArray and hexArray arguments refer to the same array object, or if any of these arguments refer to an array view sharing components with the other argument, then the conversion is performed as if the components at positions bOff through bOff+bLen-1 were first copied to a temporary array with bLen components and then the contents of the temporary array were converted into positions outOff onwards for the converted bytes of the output array.

Parameters:

hexArray - input byte array

bOff - offset within byte array containing first byte (the high order byte)

bLen - byte length of input hex data

bcdArray - output byte array

outOff - offset within bcdArray where output data begins

Returns:

the byte length of the output bcd formatted data

Throws:

ArrayIndexOutOfBoundsException - if converting would cause access of data outside array bounds or if bLen is negative

NullPointerException - if either bcdArray or hexArray is null

ArithmeticException - for the following conditions:

• if the length of the input hex value is larger than the supported maximum number of bytes
• if bLen is 0

isBCDFormat

public static boolean isBCDFormat(byte[] bcdArray,
                                  short bOff,
                                  short bLen)

Checks if the input data is in BCD format. Note that this method does not enforce an upper bound on the length of the input BCD value.

Parameters:

bcdArray - input byte array

bOff - offset within byte array containing first byte (the high order byte)

bLen - byte length of input BCD data

Returns:

true if input data is in BCD format, false otherwise

Throws:

ArrayIndexOutOfBoundsException - if accessing the input array would cause access of data outside array bounds or if bLen is negative

NullPointerException - if bcdArray is null

ArithmeticException - if bLen is 0