Class JCint

java.lang.Object

javacardx.framework.util.intx.JCint

public final class JCint
extends Object

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

The methods makeTransientIntArray() and and setInt(), 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 makeTransientIntArray() method is used to create transient int arrays. Constants related to transience control are available in the JCSystem class.

Since:

2.2.2

See Also:

• javacard.framework.JCSystem

Method Summary

Modifier and Type	Method	Description
static final int	getInt(byte[] bArray, short bOff)	Concatenates four bytes in a byte array to form a int value.
static final int	makeInt(byte b1, byte b2, byte b3, byte b4)	Concatenates the four parameter bytes to form an int value.
static final int	makeInt(short s1, short s2)	Concatenates the two parameter short values to form an int value.
static int[]	makeIntArrayView(int[] array, short offset, short length, short attributes, Shareable service)	Creates an int array which is a view on the specified array parameter.
static int[]	makeTransientIntArray(short length, byte event)	Creates a transient int array with the specified array length.
static final short	setInt(byte[] bArray, short bOff, int iValue)	Deposits the int value as four successive bytes at the specified offset in the byte array.

Methods inherited from class Object

equals

Modifier and Type	Method	Description
boolean	equals(Object obj)	Compares two Objects for equality.

Method Details

makeInt

public static final int makeInt(byte b1,
 byte b2,
 byte b3,
 byte b4)

Concatenates the four parameter bytes to form an int value.

Parameters:

b1 - the first byte ( high order byte )

b2 - the second byte

b3 - the third byte

b4 - the fourth byte ( low order byte )

Returns:

the int value the concatenated result

makeInt

public static final int makeInt(short s1,
 short s2)

Concatenates the two parameter short values to form an int value.

Parameters:

s1 - the first short value ( high order short value )

s2 - the second short value ( low order short value )

Returns:

the int value the concatenated result

getInt

public static final int getInt(byte[] bArray,
 short bOff)
                        throws NullPointerException,
ArrayIndexOutOfBoundsException

Concatenates four bytes in a byte array to form a int value.

Parameters:

bArray - byte array

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

Returns:

the int value the concatenated result

Throws:

NullPointerException - if the bArray parameter is null

ArrayIndexOutOfBoundsException - if the bOff parameter is negative or if bOff+4 is greater than the length of bArray

setInt

public static final short setInt(byte[] bArray,
 short bOff,
 int iValue)
                          throws TransactionException,
NullPointerException,
ArrayIndexOutOfBoundsException

Deposits the int value as four 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)

iValue - the short value to set into array.

Returns:

bOff+4

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

NullPointerException - if the bArray parameter is null

ArrayIndexOutOfBoundsException - if the bOff parameter is negative or if bOff+4 is greater than the length of bArray

See Also:

• javacard.framework.JCSystem.getUnusedCommitCapacity()

makeTransientIntArray

public static int[] makeTransientIntArray(short length,
 byte event)
                                   throws NegativeArraySizeException,
SystemException

Creates a transient int array with the specified array length.

Parameters:

length - the length of the int array

event - the CLEAR_ON... event which causes the array elements to be cleared

Returns:

the new transient int array

Throws:

NegativeArraySizeException - if the length parameter is negative

SystemException - with the following reason codes:

• SystemException.ILLEGAL_VALUE if event is not a valid event code.
• SystemException.NO_TRANSIENT_SPACE if sufficient transient space is not available.
• SystemException.ILLEGAL_TRANSIENT if the current applet context is not the currently selected applet context and CLEAR_ON_DESELECT is specified.

See Also:

• javacard.framework.JCSystem

makeIntArrayView

public static int[] makeIntArrayView(int[] array,
 short offset,
 short length,
 short attributes,
 Shareable service)

Creates an int array which is a view on the specified array parameter. The elements of the created array are mapped to the corresponding elements in the parent array. Any change in the parent array will be visible in the view and vice versa.

The layout attributes (transient, persistent, sensitive) of the created array are identical to the array parameter ones.
In addition, it is possible to create read-only, write-only or R/W views using combinations (bitwise inclusive OR) of the following access attributes:

• ATTR_READABLE_VIEW: the elements of the view can be read. If this attribute is not set, any attempt to read elements from the created view will throw a SecurityException
• ATTR_WRITABLE_VIEW: the elements of the view can be modified and changes are visible in the actual array and any other view on it. If this attribute is not set, any attempt to write elements in the created view will throw a SecurityException

The attributes requested for the view shall remain consistent with the attributes of the array parameter:

• Any attempt to create a view with the ATTR_READABLE_VIEW attribute will throw a SecurityException if the array parameter is not readable.
• Any attempt to create a view with the ATTR_WRITABLE_VIEW attribute will throw a SecurityException if the array parameter is not writable.

The created view is temporary and any attempt to store the reference into a class or instance field or in array elements will throw a SecurityException

Example:

// creates a R/W view of 5 int on array, starting at offset 4
int[] view = JCint.makeIntArrayView(array, (short) 4, (short) 5,
        (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), null);

// creates a view in the service context and share it with the service
int[] view = JCint.makeIntArrayView(array, (short) 4, (short) 5,
        (short) (ATTR_READABLE_VIEW | ATTR_WRITABLE_VIEW), service);
service.execute(view);

Parameters:

array - the array on which to create the view (either an actual array or a view)

offset - the offset in the array where the view starts

length - the number of elements in the view

attributes - the view access attributes (combinations of ATTR_READABLE_VIEW and ATTR_WRITABLE_VIEW attributes)

service - the shareable object identifying the recipient context of the new view. If null, the view will remain in the current context. If non-null, the method returns an object created in the context of the specified service and should be used as parameter when calling methods of this service. Other operations executed in current context, including casting, will throw a SecurityException.

Returns:

a view on the specified array parameter

Throws:

NullPointerException - if the array parameter is null

NegativeArraySizeException - if the length parameter is negative

SecurityException -

• if the array cannot be accessed from current context
• if requesting access attributes that were not available for the array parameter

SystemException - with the following reason code:

• SystemException.ILLEGAL_VALUE if the array parameter is not an array
• SystemException.NO_RESOURCE if not enough resources to allocate the view

ArrayIndexOutOfBoundsException - if the view would cause access of data outside array bounds

Since:

3.1