content: /*
   * Copyright (C) 2007 The Android Open Source Project
   *
   * 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 com.taobao.android.dx.dex.code;
  
  import com.taobao.android.dx.rop.code.RegisterSpecList;
  import com.taobao.android.dx.rop.code.SourcePosition;
  
  /**
   * Instruction which has a single branch target.
   */
  public final class TargetInsn extends FixedSizeInsn {
      /** {@code non-null;} the branch target */
      private CodeAddress target;
  
      /**
       * Constructs an instance. The output address of this instance is initially
       * unknown ({@code -1}), and the target is initially
       * {@code null}.
       *
       * @param opcode the opcode; one of the constants from {@link Dops}
       * @param position {@code non-null;} source position
       * @param registers {@code non-null;} register list, including a
       * result register if appropriate (that is, registers may be either
       * ins or outs)
       * @param target {@code non-null;} the branch target
       */
      public TargetInsn(Dop opcode, SourcePosition position,
                        RegisterSpecList registers, CodeAddress target) {
          super(opcode, position, registers);
  
          if (target == null) {
              throw new NullPointerException("target == null");
          }
  
          this.target = target;
      }
  
      /** {@inheritDoc} */
      @Override
      public DalvInsn withOpcode(Dop opcode) {
          return new TargetInsn(opcode, getPosition(), getRegisters(), target);
      }
  
      /** {@inheritDoc} */
      @Override
      public DalvInsn withRegisters(RegisterSpecList registers) {
          return new TargetInsn(getOpcode(), getPosition(), registers, target);
      }
  
      /**
       * Returns an instance that is just like this one, except that its
       * opcode has the opposite sense (as a test; e.g. a
       * {@code lt} test becomes a {@code ge}), and its branch
       * target is replaced by the one given, and all set-once values
       * associated with the class (such as its address) are reset.
       *
       * @param target {@code non-null;} the new branch target
       * @return {@code non-null;} an appropriately-constructed instance
       */
      public TargetInsn withNewTargetAndReversed(CodeAddress target) {
          Dop opcode = getOpcode().getOppositeTest();
  
          return new TargetInsn(opcode, getPosition(), getRegisters(), target);
      }
  
      /**
       * Gets the unique branch target of this instruction.
       *
       * @return {@code non-null;} the branch target
       */
      public CodeAddress getTarget() {
          return target;
      }
  
      /**
       * Gets the target address of this instruction. This is only valid
       * to call if the target instruction has been assigned an address,
       * and it is merely a convenient shorthand for
       * {@code getTarget().getAddress()}.
       *
       * @return {@code >= 0;} the target address
       */
      public int getTargetAddress() {
          return target.getAddress();
      }
  
      /**
       * Gets the branch offset of this instruction. This is only valid to
       * call if both this and the target instruction each has been assigned
       * an address, and it is merely a convenient shorthand for
       * {@code getTargetAddress() - getAddress()}.
       *
       * @return the branch offset
       */
      public int getTargetOffset() {
          return target.getAddress() - getAddress();
      }
  
      /**
       * Returns whether the target offset is known.
       *
       * @return {@code true} if the target offset is known or
       * {@code false} if not
       */
      public boolean hasTargetOffset() {
          return hasAddress() && target.hasAddress();
      }
  
      /** {@inheritDoc} */
      @Override
      protected String argString() {
          if (target == null) {
              return "????";
          }
  
          return target.identifierString();
      }
  }
  