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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.evaluation;

import proguard.classfile.Clazz;
import proguard.classfile.attribute.CodeAttribute;
import proguard.evaluation.value.InstructionOffsetValue;

/**
 * This {@link BranchUnit} remembers the branch unit commands that are invoked on it. It doesn't
 * consider conditions when branching.
 *
 * @author Eric Lafortune
 */
public class BasicBranchUnit implements BranchUnit {
  protected InstructionOffsetValue traceBranchTargets;
  protected boolean wasCalled;

  /**
   * Resets the accumulated branch targets and the flag that tells whether any of the branch unit
   * methods was called.
   */
  public void reset() {
    traceBranchTargets = InstructionOffsetValue.EMPTY_VALUE;

    wasCalled = false;
  }

  /** Returns whether any of the branch unit methods was called. */
  public boolean wasCalled() {
    return wasCalled;
  }

  /** Returns the accumulated branch targets that were passed to the branch unit methods. */
  public InstructionOffsetValue getTraceBranchTargets() {
    return traceBranchTargets;
  }

  // Implementations for BranchUnit.

  public void branch(Clazz clazz, CodeAttribute codeAttribute, int offset, int branchTarget) {
    // Override the branch targets.
    traceBranchTargets = new InstructionOffsetValue(branchTarget);

    wasCalled = true;
  }

  public void branchConditionally(
      Clazz clazz, CodeAttribute codeAttribute, int offset, int branchTarget, int conditional) {
    // Accumulate the branch targets.
    traceBranchTargets = traceBranchTargets.add(branchTarget);

    wasCalled = true;
  }

  public void returnFromMethod() {
    // Stop processing this block.
    traceBranchTargets = InstructionOffsetValue.EMPTY_VALUE;

    wasCalled = true;
  }

  public void throwException() {
    // Stop processing this block.
    traceBranchTargets = InstructionOffsetValue.EMPTY_VALUE;

    wasCalled = true;
  }
}