jef.dna.instructions.impl
Class Wide

java.lang.Object
  jef.dna.instructions.impl.InstructionAncestor
      jef.dna.instructions.impl.Wide

All Implemented Interfaces:

java.lang.Cloneable, Instruction, BytesCountable

public class Wide
extends InstructionAncestor

This class maps the WIDE bytecode instruction which extends local variable index by additional bytes. The wide instruction modifies the behavior of another instruction. It takes one of two formats, depending on the instruction being modified. The widened bytecode operates as normal, except for the use of the wider index and, in the case of the second form, the larger increment range.

Author:

frusso

Field Summary

Fields inherited from class jef.dna.instructions.impl.InstructionAncestor

logger, opCode, operands, operandsCount

Constructor Summary

Wide()
Creates a new instance of Wide

Method Summary

void	setOperandsCountPosticipated(int[] bytecode, int startFrom) This method should be implemented by those classes wrapping JVM instructions whose number of operands is variable.
int	updateRefs(int offset) This method must implement the logic necessary to update all the references to constant pool table's entries contained within the bytecode instruction.

Methods inherited from class jef.dna.instructions.impl.InstructionAncestor

clone, fromArray, getBytesCount, getOpCode, getOperands, getOperandsCount, setOpCode, setOperands, toArray

Methods inherited from class java.lang.Object

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

Constructor Detail

Wide

public Wide()

Creates a new instance of Wide

Method Detail

setOperandsCountPosticipated

public void setOperandsCountPosticipated(int[] bytecode,
                                         int startFrom)

This method should be implemented by those classes wrapping JVM instructions whose number of operands is variable. This method is called by the fromArray method defined in the InstructionAncestor class. InstructionAncestor already contains an empty implementation of this method, useful for those classes exposing a prefixed number of operands. In such a case there is no need to override the setOperandsCountPosticipated method,

Specified by:

setOperandsCountPosticipated in interface Instruction

Overrides:

setOperandsCountPosticipated in class InstructionAncestor

Parameters:

bytecode - The method's bytecode

startFrom - The index of the current instruction's mnemonic (opcode)

updateRefs

public int updateRefs(int offset)

This method must implement the logic necessary to update all the references to constant pool table's entries contained within the bytecode instruction.

Specified by:

updateRefs in interface Instruction

Overrides:

updateRefs in class InstructionAncestor

Parameters:

offset - The offset used for updating expressed as number of cpt's entries to be skipped

Returns:

int The number of processed words within the current bytecode instruction