proguard.classfile.instruction.LookUpSwitchInstruction Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of proguard-core Show documentation
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.instruction;

import java.util.Arrays;
import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.instruction.visitor.InstructionVisitor;

/**
 * This {@link Instruction} represents a lookup switch instruction.
 *
 * @author Eric Lafortune
 */
public class LookUpSwitchInstruction extends SwitchInstruction {
  public int[] cases;

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

  /**
   * Creates a new LookUpSwitchInstruction with the given arguments. All offsets are relative to
   * this instruction's offset.
   */
  public LookUpSwitchInstruction(byte opcode, int defaultOffset, int[] cases, int[] jumpOffsets) {
    this.opcode = opcode;
    this.defaultOffset = defaultOffset;
    this.cases = cases;
    this.jumpOffsets = jumpOffsets;
  }

  /**
   * Copies the given instruction into this instruction.
   *
   * @param lookUpSwitchInstruction the instruction to be copied.
   * @return this instruction.
   */
  public LookUpSwitchInstruction copy(LookUpSwitchInstruction lookUpSwitchInstruction) {
    this.opcode = lookUpSwitchInstruction.opcode;
    this.defaultOffset = lookUpSwitchInstruction.defaultOffset;
    this.cases = lookUpSwitchInstruction.cases;
    this.jumpOffsets = lookUpSwitchInstruction.jumpOffsets;

    return this;
  }

  // Implementations for Instruction.

  public Instruction shrink() {
    // There aren't any ways to shrink this instruction.
    return this;
  }

  protected void readInfo(byte[] code, int offset) {
    // Skip up to three padding bytes.
    offset += -offset & 3;

    // Read the two 32-bit arguments.
    defaultOffset = readInt(code, offset);
    offset += 4;
    int jumpOffsetCount = readInt(code, offset);
    offset += 4;

    // Read the matches-offset pairs.
    cases = new int[jumpOffsetCount];
    jumpOffsets = new int[jumpOffsetCount];

    for (int index = 0; index < jumpOffsetCount; index++) {
      cases[index] = readInt(code, offset);
      offset += 4;
      jumpOffsets[index] = readInt(code, offset);
      offset += 4;
    }
  }

  protected void writeInfo(byte[] code, int offset) {
    // Write up to three padding bytes.
    while ((offset & 3) != 0) {
      writeByte(code, offset++, 0);
    }

    // Write the two 32-bit arguments.
    writeInt(code, offset, defaultOffset);
    offset += 4;
    writeInt(code, offset, cases.length);
    offset += 4;

    // Write the matches-offset pairs.
    for (int index = 0; index < cases.length; index++) {
      writeInt(code, offset, cases[index]);
      offset += 4;
      writeInt(code, offset, jumpOffsets[index]);
      offset += 4;
    }
  }

  public int length(int offset) {
    return 1 + (-(offset + 1) & 3) + 8 + cases.length * 8;
  }

  public void accept(
      Clazz clazz,
      Method method,
      CodeAttribute codeAttribute,
      int offset,
      InstructionVisitor instructionVisitor) {
    instructionVisitor.visitLookUpSwitchInstruction(clazz, method, codeAttribute, offset, this);
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (!super.equals(o)) return false;
    LookUpSwitchInstruction that = (LookUpSwitchInstruction) o;
    return Arrays.equals(cases, that.cases);
  }

  @Override
  public int hashCode() {
    int result = super.hashCode();
    result = 31 * result + Arrays.hashCode(cases);
    return result;
  }
}