com.fitbur.bytebuddy.implementation.bytecode.StackSize Maven / Gradle / Ivy
package com.fitbur.bytebuddy.implementation.bytecode;
/**
* 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;
}
}
/**
* Returns the sum of all operand stack sizes.
*
* @param types The types of interest.
* @return The sum of their sizes.
*/
public static int sizeOf(Iterable> types) {
int size = 0;
for (Class type : types) {
size += of(type).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();
}
}
@Override
public String toString() {
return "StackSize." + name();
}
}