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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.ExceptionsAttribute;

/**
 * This class can add exceptions to a given exceptions attribute. Exceptions to be added must have
 * been added to the constant pool and filled out beforehand.
 *
 * @author Eric Lafortune
 */
public class ExceptionsAttributeEditor {
  private ExceptionsAttribute targetExceptionsAttribute;

  /**
   * Creates a new ExceptionsAttributeEditor that will edit exceptions in the given exceptions
   * attribute.
   */
  public ExceptionsAttributeEditor(ExceptionsAttribute targetExceptionsAttribute) {
    this.targetExceptionsAttribute = targetExceptionsAttribute;
  }

  /** Adds a given exception to the exceptions attribute. */
  public void addException(int exceptionIndex) {
    int exceptionIndexTableLength = targetExceptionsAttribute.u2exceptionIndexTableLength;
    int[] exceptionIndexTable = targetExceptionsAttribute.u2exceptionIndexTable;

    // Make sure there is enough space for the new exception.
    if (exceptionIndexTable.length <= exceptionIndexTableLength) {
      targetExceptionsAttribute.u2exceptionIndexTable = new int[exceptionIndexTableLength + 1];
      System.arraycopy(
          exceptionIndexTable,
          0,
          targetExceptionsAttribute.u2exceptionIndexTable,
          0,
          exceptionIndexTableLength);
      exceptionIndexTable = targetExceptionsAttribute.u2exceptionIndexTable;
    }

    // Add the exception.
    exceptionIndexTable[targetExceptionsAttribute.u2exceptionIndexTableLength++] = exceptionIndex;
  }
}