Package com.tonic.analysis.execution.state

Class ConcreteStack

java.lang.Object

com.tonic.analysis.execution.state.ConcreteStack

public final class ConcreteStack
extends Object

Fixed-capacity operand stack of concrete values with the JVM dup and swap shuffle operations.

Constructor Summary

Constructors

Constructor	Description
ConcreteStack(int maxStack)	Creates an empty stack.

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all values.
int	depth()
void	dup()	Duplicates the top value.
void	dup2()	Duplicates the top two slots: one wide value or two narrow values.
void	dup2X1()	Duplicates the top two values beneath the third value.
void	dup2X2()	Duplicates the top two values beneath the fourth value.
void	dupX1()	Duplicates the top value beneath the second value.
void	dupX2()	Duplicates the top value beneath the third value.
ConcreteValue	get(int index)	Reads a value by absolute index from the bottom.
boolean	isEmpty()
int	maxDepth()
ConcreteValue	peek()	Reads the top value without popping.
ConcreteValue	peek(int depth)	Reads a value below the top without popping.
ConcreteValue	pop()	Pops the top value.
void	pop(int count)	Discards values from the top.
double	popDouble()	Pops the top value as a double.
float	popFloat()	Pops the top value as a float.
int	popInt()	Pops the top value as an int.
long	popLong()	Pops the top value as a long.
ObjectInstance	popReference()	Pops the top value as a reference.
void	push(ConcreteValue value)	Pushes a value.
void	pushDouble(double value)	Pushes a double.
void	pushFloat(float value)	Pushes a float.
void	pushInt(int value)	Pushes an int.
void	pushLong(long value)	Pushes a long.
void	pushNull()	Pushes a null reference.
void	pushReference(ObjectInstance instance)	Pushes a reference, mapping null to the null value.
void	set(int index, ConcreteValue value)	Replaces a value by absolute index from the bottom.
List<ConcreteValue>	snapshot()	Captures the stack bottom-to-top as an unmodifiable list.
void	swap()	Swaps the top two values.
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ConcreteStack

public ConcreteStack(int maxStack)

Creates an empty stack.

Parameters:

maxStack - capacity in slots

Method Detail

push

public void push(ConcreteValue value)

Pushes a value.

Parameters:

value - value to push

Throws:

StackOverflowError - if the stack is full

pushInt

public void pushInt(int value)

Pushes an int.

Parameters:

value - value to push

pushLong

public void pushLong(long value)

Pushes a long.

Parameters:

value - value to push

pushFloat

public void pushFloat(float value)

Pushes a float.

Parameters:

value - value to push

pushDouble

public void pushDouble(double value)

Pushes a double.

Parameters:

value - value to push

pushReference

public void pushReference(ObjectInstance instance)

Pushes a reference, mapping null to the null value.

Parameters:

instance - instance to push, may be null

pushNull

public void pushNull()

Pushes a null reference.

pop

public ConcreteValue pop()

Pops the top value.

Returns:

the popped value

Throws:

IllegalStateException - if the stack is empty

popInt

public int popInt()

Pops the top value as an int.

Returns:

the int value

popLong

public long popLong()

Pops the top value as a long.

Returns:

the long value

popFloat

public float popFloat()

Pops the top value as a float.

Returns:

the float value

popDouble

public double popDouble()

Pops the top value as a double.

Returns:

the double value

popReference

public ObjectInstance popReference()

Pops the top value as a reference.

Returns:

the instance, or null for a null reference

pop

public void pop(int count)

Discards values from the top.

Parameters:

count - number of values to discard

Throws:

IllegalArgumentException - if the count is negative

IllegalStateException - if the count exceeds the current depth

peek

public ConcreteValue peek()

Reads the top value without popping.

Returns:

the top value

Throws:

IllegalStateException - if the stack is empty

peek

public ConcreteValue peek(int depth)

Reads a value below the top without popping.

Parameters:

depth - distance from the top, zero for the top

Returns:

the value at that depth

Throws:

IllegalStateException - if the depth is out of range

set

public void set(int index,
                ConcreteValue value)

Replaces a value by absolute index from the bottom.

Parameters:

index - absolute index

value - replacement value

Throws:

IndexOutOfBoundsException - if the index is out of range

IllegalArgumentException - if the value is null

get

public ConcreteValue get(int index)

Reads a value by absolute index from the bottom.

Parameters:

index - absolute index

Returns:

the value at that index

Throws:

IndexOutOfBoundsException - if the index is out of range

dup

public void dup()

Duplicates the top value.

dupX1

public void dupX1()

Duplicates the top value beneath the second value.

dupX2

public void dupX2()

Duplicates the top value beneath the third value.

dup2

public void dup2()

Duplicates the top two slots: one wide value or two narrow values.

dup2X1

public void dup2X1()

Duplicates the top two values beneath the third value.

dup2X2

public void dup2X2()

Duplicates the top two values beneath the fourth value.

swap

public void swap()

Swaps the top two values.

depth

public int depth()

Returns:

the current number of values

maxDepth

public int maxDepth()

Returns:

the capacity

isEmpty

public boolean isEmpty()

Returns:

true if no values are on the stack

clear

public void clear()

Removes all values.

snapshot

public List<ConcreteValue> snapshot()

Captures the stack bottom-to-top as an unmodifiable list.

Returns:

the current values

toString

public String toString()

Overrides:

toString in class Object