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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.editor;

import proguard.classfile.attribute.*;
import proguard.util.ArrayUtil;

/**
 * This class can add/remove bootstrap methods to/from a given bootstrap methods attribute.
 * Bootstrap methods to be added must have been filled out beforehand.
 *
 * @author Eric Lafortune
 */
public class BootstrapMethodsAttributeEditor {
  private BootstrapMethodsAttribute targetBootstrapMethodsAttribute;

  /**
   * Creates a new BootstrapMethodsAttributeEditor that will edit bootstrap methods in the given
   * bootstrap methods attribute.
   */
  public BootstrapMethodsAttributeEditor(
      BootstrapMethodsAttribute targetBootstrapMethodsAttribute) {
    this.targetBootstrapMethodsAttribute = targetBootstrapMethodsAttribute;
  }

  /**
   * Adds a given bootstrap method to the bootstrap methods attribute.
   *
   * @return the index of the bootstrap method.
   */
  public int addBootstrapMethodInfo(BootstrapMethodInfo bootstrapMethodInfo) {
    targetBootstrapMethodsAttribute.bootstrapMethods =
        ArrayUtil.add(
            targetBootstrapMethodsAttribute.bootstrapMethods,
            targetBootstrapMethodsAttribute.u2bootstrapMethodsCount,
            bootstrapMethodInfo);

    return targetBootstrapMethodsAttribute.u2bootstrapMethodsCount++;
  }

  /** Removes the given bootstrap method from the bootstrap method attribute. */
  public void removeBootstrapMethodInfo(BootstrapMethodInfo bootstrapMethodInfo) {
    ArrayUtil.remove(
        targetBootstrapMethodsAttribute.bootstrapMethods,
        targetBootstrapMethodsAttribute.u2bootstrapMethodsCount--,
        findBootstrapMethodInfoIndex(bootstrapMethodInfo));
  }

  /** Finds the index of the given bootstrap method info in the target attribute. */
  private int findBootstrapMethodInfoIndex(BootstrapMethodInfo bootstrapMethodInfo) {
    int methodsCount = targetBootstrapMethodsAttribute.u2bootstrapMethodsCount;
    BootstrapMethodInfo[] methodInfos = targetBootstrapMethodsAttribute.bootstrapMethods;

    for (int index = 0; index < methodsCount; index++) {
      if (methodInfos[index].equals(bootstrapMethodInfo)) {
        return index;
      }
    }

    return methodsCount;
  }
}