Java Card
v2.2.2

javacard.framework
Class Util

java.lang.Object
  extended by javacard.framework.Util

public class Util
extends Object

The Util class contains common utility functions. Some of the methods may be implemented as native functions for performance reasons. All methods in Util, class are static methods.

Some methods of Util, namely arrayCopy(), arrayCopyNonAtomic(), arrayFillNonAtomic() and setShort(), refer to the persistence of array objects. The term persistent means that arrays and their values persist from one CAD session to the next, indefinitely. The JCSystem class is used to control the persistence and transience of objects.

See Also:
JCSystem

Method Summary
static byte arrayCompare(byte[] src, short srcOff, byte[] dest, short destOff, short length)
          Compares an array from the specified source array, beginning at the specified position, with the specified position of the destination array from left to right.
static short arrayCopy(byte[] src, short srcOff, byte[] dest, short destOff, short length)
          Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array.
static short arrayCopyNonAtomic(byte[] src, short srcOff, byte[] dest, short destOff, short length)
          Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array (non-atomically).
static short arrayFillNonAtomic(byte[] bArray, short bOff, short bLen, byte bValue)
          Fills the byte array (non-atomically) beginning at the specified position, for the specified length with the specified byte value.
static short getShort(byte[] bArray, short bOff)
          Concatenates two bytes in a byte array to form a short value.
static short makeShort(byte b1, byte b2)
          Concatenates the two parameter bytes to form a short value.
static short setShort(byte[] bArray, short bOff, short sValue)
          Deposits the short value as two successive bytes at the specified offset in the byte array.
 
Methods inherited from class java.lang.Object
equals
 

Method Detail

arrayCopy

public static final short arrayCopy(byte[] src,
                                    short srcOff,
                                    byte[] dest,
                                    short destOff,
                                    short length)
                             throws ArrayIndexOutOfBoundsException,
                                    NullPointerException,
                                    TransactionException
Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array.

Note:

Parameters:
src - source byte array
srcOff - offset within source byte array to start copy from
dest - destination byte array
destOff - offset within destination byte array to start copy into
length - byte length to be copied
Returns:
destOff+length
Throws:
ArrayIndexOutOfBoundsException - if copying would cause access of data outside array bounds
NullPointerException - if either src or dest is null
TransactionException - if copying would cause the commit capacity to be exceeded
See Also:
JCSystem.getUnusedCommitCapacity()

arrayCopyNonAtomic

public static final short arrayCopyNonAtomic(byte[] src,
                                             short srcOff,
                                             byte[] dest,
                                             short destOff,
                                             short length)
                                      throws ArrayIndexOutOfBoundsException,
                                             NullPointerException
Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array (non-atomically).

This method does not use the transaction facility during the copy operation even if a transaction is in progress. Thus, this method is suitable for use only when the contents of the destination array can be left in a partially modified state in the event of a power loss in the middle of the copy operation.

Note:

Parameters:
src - source byte array
srcOff - offset within source byte array to start copy from
dest - destination byte array
destOff - offset within destination byte array to start copy into
length - byte length to be copied
Returns:
destOff+length
Throws:
ArrayIndexOutOfBoundsException - if copying would cause access of data outside array bounds
NullPointerException - if either src or dest is null
See Also:
JCSystem.getUnusedCommitCapacity()

arrayFillNonAtomic

public static final short arrayFillNonAtomic(byte[] bArray,
                                             short bOff,
                                             short bLen,
                                             byte bValue)
                                      throws ArrayIndexOutOfBoundsException,
                                             NullPointerException
Fills the byte array (non-atomically) beginning at the specified position, for the specified length with the specified byte value.

This method does not use the transaction facility during the fill operation even if a transaction is in progress. Thus, this method is suitable for use only when the contents of the byte array can be left in a partially filled state in the event of a power loss in the middle of the fill operation.

Note:

Parameters:
bArray - the byte array
bOff - offset within byte array to start filling bValue into
bLen - byte length to be filled
bValue - the value to fill the byte array with
Returns:
bOff+bLen
Throws:
ArrayIndexOutOfBoundsException - if the fill operation would cause access of data outside array bounds
NullPointerException - if bArray is null
See Also:
JCSystem.getUnusedCommitCapacity()

arrayCompare

public static final byte arrayCompare(byte[] src,
                                      short srcOff,
                                      byte[] dest,
                                      short destOff,
                                      short length)
                               throws ArrayIndexOutOfBoundsException,
                                      NullPointerException
Compares an array from the specified source array, beginning at the specified position, with the specified position of the destination array from left to right. Returns the ternary result of the comparison : less than(-1), equal(0) or greater than(1).

Note:

Parameters:
src - source byte array
srcOff - offset within source byte array to start compare
dest - destination byte array
destOff - offset within destination byte array to start compare
length - byte length to be compared
Returns:
the result of the comparison as follows:
  • 0 if identical
  • -1 if the first miscomparing byte in source array is less than that in destination array
  • 1 if the first miscomparing byte in source array is greater that that in destination array
Throws:
ArrayIndexOutOfBoundsException - if comparing all bytes would cause access of data outside array bounds
NullPointerException - if either src or dest is null

makeShort

public static final short makeShort(byte b1,
                                    byte b2)
Concatenates the two parameter bytes to form a short value.

Parameters:
b1 - the first byte ( high order byte )
b2 - the second byte ( low order byte )
Returns:
the short value the concatenated result

getShort

public static final short getShort(byte[] bArray,
                                   short bOff)
                            throws NullPointerException,
                                   ArrayIndexOutOfBoundsException
Concatenates two bytes in a byte array to form a short value.

Parameters:
bArray - byte array
bOff - offset within byte array containing first byte (the high order byte)
Returns:
the short value the concatenated result
Throws:
NullPointerException - if the bArray parameter is null
ArrayIndexOutOfBoundsException - if the bOff parameter is negative or if bOff+2 is greater than the length of bArray

setShort

public static final short setShort(byte[] bArray,
                                   short bOff,
                                   short sValue)
                            throws TransactionException,
                                   NullPointerException,
                                   ArrayIndexOutOfBoundsException
Deposits the short value as two successive bytes at the specified offset in the byte array.

Parameters:
bArray - byte array
bOff - offset within byte array to deposit the first byte (the high order byte)
sValue - the short value to set into array.
Returns:
bOff+2

Note:

  • If the byte array is persistent, this operation is performed atomically. If the commit capacity is exceeded, no operation is performed and a TransactionException exception is thrown.
Throws:
TransactionException - if the operation would cause the commit capacity to be exceeded
ArrayIndexOutOfBoundsException - if the bOff parameter is negative or if bOff+2 is greater than the length of bArray
NullPointerException - if the bArray parameter is null
See Also:
JCSystem.getUnusedCommitCapacity()

Java Card
v2.2.2

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