Class VariableInstructionForm

java.lang.Object

org.apache.commons.compress.harmony.unpack200.bytecode.forms.ByteCodeForm

org.apache.commons.compress.harmony.unpack200.bytecode.forms.VariableInstructionForm

Direct Known Subclasses:

SwitchForm, WideForm

public abstract class VariableInstructionForm
extends ByteCodeForm

This abstract class implements the common code for instructions which have variable lengths. This is currently the *switch instructions and some wide (_w) instructions.

Field Summary

Fields inherited from class ByteCodeForm

byteCodeArray, byteCodesByName, WIDENED

Constructor Summary

Constructors

Constructor	Description
VariableInstructionForm(int opcode, String name)	Constructs a new instance with the specified opcode, name, operandType and rewrite.

Method Summary

Modifier and Type	Method	Description
void	setRewrite2Bytes(int operand, int absPosition, int[] rewrite)	This method writes operand directly into the rewrite array at index position specified.
void	setRewrite4Bytes(int operand, int[] rewrite)	Given an int operand, set the rewrite bytes for the next available operand position and the three immediately following it to a highest-byte, mid-high, mid-low, low-byte encoding of the operand.
void	setRewrite4Bytes(int operand, int absPosition, int[] rewrite)	This method writes operand directly into the rewrite array at index position specified.

Methods inherited from class ByteCodeForm

calculateOperandPosition, firstOperandIndex, fixUpByteCodeTargets, get, getName, getOpcode, getRewrite, getRewriteCopy, hasMultipleByteCodes, hasNoOperand, nestedMustStartClassPool, operandLength, setByteCodeOperands, toString

Methods inherited from class Object

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

Constructor Details

VariableInstructionForm

public VariableInstructionForm(int opcode,
 String name)

Constructs a new instance with the specified opcode, name, operandType and rewrite.

Parameters:

opcode - index corresponding to the opcode's value.

name - String printable name of the opcode.

Method Details

setRewrite2Bytes

public void setRewrite2Bytes(int operand,
 int absPosition,
 int[] rewrite)

This method writes operand directly into the rewrite array at index position specified.

Parameters:

operand - value to write

absPosition - position in array to write. Note that this is absolute position in the array, so one can overwrite the bytecode if one isn't careful.

rewrite - array to write into

setRewrite4Bytes

public void setRewrite4Bytes(int operand,
 int absPosition,
 int[] rewrite)

This method writes operand directly into the rewrite array at index position specified.

Parameters:

operand - value to write

absPosition - position in array to write. Note that this is absolute position in the array, so one can overwrite the bytecode if one isn't careful.

rewrite - array to write into

setRewrite4Bytes

public void setRewrite4Bytes(int operand,
 int[] rewrite)

Given an int operand, set the rewrite bytes for the next available operand position and the three immediately following it to a highest-byte, mid-high, mid-low, low-byte encoding of the operand. Note that unlike the ByteCode setOperand* operations, this starts with an actual bytecode rewrite array (rather than a ByteCodeForm prototype rewrite array). Also, this method overwrites -1 values in the rewrite array - so if you start with an array that looks like: {100, -1, -1, -1, -1, 200, -1, -1, -1, -1} then calling setRewrite4Bytes(0, rewrite) the first time will convert it to: {100, 0, 0, 0, 0, 200, -1, -1, -1, -1} Calling setRewrite4Bytes(0, rewrite) a second time will convert it to: {100, 0, 0, 0, 0, 200, 0, 0, 0, 0}

Parameters:

operand - int to set the rewrite bytes to

rewrite - int[] bytes to rewrite