package net.bytebuddy.implementation.bytecode;
import net.bytebuddy.description.type.
TypeDefinition;
import java.util.
Arrays;
import java.util.
Collection;
/**
* Represents the size of a Java type on the operand stack.
*/
public enum
StackSize {
/**
* An empty stack size.
*/
ZERO(0),
/**
* A single slot stack size.
*/
SINGLE(1),
/**
* A double slot stack size which is required by {@code long} and {@code double} values.
*/
DOUBLE(2);
/**
* The size of the stack this instance represents.
*/
private final int
size;
/**
* Creates a new stack size.
*
* @param size The size of the stack this instance represents.
*/
StackSize(int
size) {
this.
size =
size;
}
/**
* Finds the operand stack size of a given Java type.
*
* @param type The type of interest.
* @return The given type's operand stack size.
*/
public static
StackSize of(
Class<?>
type) {
if (
type == void.class) {
return
ZERO;
} else if (
type == double.class ||
type == long.class) {
return
DOUBLE;
} else {
return
SINGLE;
}
}
/**
* Represents a numeric size as a {@link StackSize}.
*
* @param size The size to represent. Must be {@code 0}, {@code 1} or {@code 2}.
* @return A stack size representation for the given value.
*/
public static
StackSize of(int
size) {
switch (
size) {
case 0:
return
ZERO;
case 1:
return
SINGLE;
case 2:
return
DOUBLE;
default:
throw new
IllegalArgumentException("Unexpected stack size value: " +
size);
}
}
/**
* Computes the stack size of all supplied types.
*
* @param typeDefinition The types for which to compute the size.
* @return The total size of all types.
*/
public static int
of(
TypeDefinition...
typeDefinition) {
return
of(
Arrays.
asList(
typeDefinition));
}
/**
* Computes the stack size of all supplied types.
*
* @param typeDefinitions The types for which to compute the size.
* @return The total size of all types.
*/
public static int
of(
Collection<? extends
TypeDefinition>
typeDefinitions) {
int
size = 0;
for (
TypeDefinition typeDefinition :
typeDefinitions) {
size +=
typeDefinition.
getStackSize().
getSize();
}
return
size;
}
/**
* The numeric value of this stack size representation.
*
* @return An integer representing the operand stack size.
*/
public int
getSize() {
return
size;
}
/**
* Creates an instance of a
* {@link StackManipulation.Size}
* that describes a stack growth of this size.
*
* @return A stack size growth by the size represented by this stack size.
*/
public
StackManipulation.
Size toIncreasingSize() {
return new
StackManipulation.
Size(
getSize(),
getSize());
}
/**
* Creates an instance of a
* {@link StackManipulation.Size}
* that describes a stack decrease of this size.
*
* @return A stack size decrease by the size represented by this stack size.
*/
public
StackManipulation.
Size toDecreasingSize() {
return new
StackManipulation.
Size(-1 *
getSize(), 0);
}
/**
* Determines the maximum of two stack size representations.
*
* @param stackSize The other stack size representation.
* @return The maximum of this and the other stack size.
*/
public
StackSize maximum(
StackSize stackSize) {
switch (this) {
case
ZERO:
return
stackSize;
case
SINGLE:
switch (
stackSize) {
case
DOUBLE:
return
stackSize;
case
SINGLE:
case
ZERO:
return this;
default:
throw new
AssertionError();
}
case
DOUBLE:
return this;
default:
throw new
AssertionError();
}
}
}