net.bytebuddy.implementation.bytecode.StackSize Maven / Gradle / Ivy
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/*
* Copyright 2014 - Present Rafael Winterhalter
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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 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();
}
}
}