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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.

There is a newer version: 9.1.6

/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2020 Guardsquare NV
 *
 * 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 proguard.classfile.attribute.preverification;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.attribute.preverification.visitor.StackMapFrameVisitor;

/**
 * This {@link StackMapFrame} represents an "chop frame".
 *
 * @author Eric Lafortune
 */
public class LessZeroFrame extends StackMapFrame {
  public int choppedVariablesCount;

  /** Creates an uninitialized LessZeroFrame. */
  public LessZeroFrame() {}

  /** Creates a LessZeroFrame with the given tag. */
  public LessZeroFrame(int tag) {
    choppedVariablesCount = LESS_ZERO_FRAME + 3 - tag;
  }

  /** Creates a LessZeroFrame with the given number of chopped variables. */
  public LessZeroFrame(byte choppedVariablesCount) {
    this.choppedVariablesCount = (int) choppedVariablesCount;
  }

  // Implementations for StackMapFrame.

  public int getTag() {
    return LESS_ZERO_FRAME + 3 - choppedVariablesCount;
  }

  public void accept(
      Clazz clazz,
      Method method,
      CodeAttribute codeAttribute,
      int offset,
      StackMapFrameVisitor stackMapFrameVisitor) {
    stackMapFrameVisitor.visitLessZeroFrame(clazz, method, codeAttribute, offset, this);
  }

  // Implementations for Object.

  public boolean equals(Object object) {
    if (!super.equals(object)) {
      return false;
    }

    LessZeroFrame other = (LessZeroFrame) object;

    return this.u2offsetDelta == other.u2offsetDelta
        && this.choppedVariablesCount != other.choppedVariablesCount;
  }

  public int hashCode() {
    return super.hashCode() ^ choppedVariablesCount;
  }

  public String toString() {
    return super.toString() + "Var: (chopped " + choppedVariablesCount + "), Stack: (empty)";
  }
}