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 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
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package com.sun.jdo.api.persistence.enhancer.classfile;


import java.io.PrintStream;

/**
 * Special instruction form for the opc_tableswitch instruction
 */

public class InsnTableSwitch extends Insn {
  /* The lowest value in the jump table */
  private int lowOp;

  /* The default target for the switch */
  private InsnTarget defaultOp;

  /* The targets for the switch - a switch value of lowOp dispatches
   * to targetsOp[0], lowOp+1 dispatches to targetsOp[1], etc. */
  private InsnTarget[] targetsOp;

  /* public accessors */

  public int nStackArgs() {
    return 1;
  }

  public int nStackResults() {
    return 0;
  }

  public String argTypes() {
      return "I";//NOI18N
  }

  public String resultTypes() {
      return "";//NOI18N
  }

  public boolean branches() {
    return true;
  }

  /**
   * Mark possible branch targets
   */
  public void markTargets() {
    defaultOp.setBranchTarget();
    for (int i=0; i<targetsOp.length; i++)
      targetsOp[i].setBranchTarget();
  }


  /**
   * Return the lowest case for the switch
   */
  public int lowCase() {
    return lowOp;
  }

  /**
   * Return the defaultTarget for the switch
   */
  public InsnTarget defaultTarget() {
    return defaultOp;
  }

  /**
   * Return the targets for the cases of the switch.
   */
  public InsnTarget[] switchTargets() {
    return targetsOp;
  }

  /**
   * Constructor for opc_tableswitch
   */
  //@olsen: made public
  public InsnTableSwitch(int lowOp, InsnTarget defaultOp, 
                         InsnTarget[] targetsOp) {
    this(lowOp, defaultOp, targetsOp, NO_OFFSET);
  }


  /* package local methods */

  void print (PrintStream out, int indent) {
    ClassPrint.spaces(out, indent);
    out.println(offset() + "  opc_tableswitch  ");//NOI18N
    for (int i=0; i<targetsOp.length; i++) {
      int index = i + lowOp;
      if (targetsOp[i].offset() != defaultOp.offset()) {
	ClassPrint.spaces(out, indent+2);
	out.println(index + " -> " + targetsOp[i].offset());//NOI18N
      }
    }
    ClassPrint.spaces(out, indent+2);
    out.println("default -> " + defaultOp.offset());//NOI18N
  }

  int store(byte[] buf, int index) {
    buf[index++] = (byte) opcode();
    index = (index + 3) & ~3;
    index = storeInt(buf, index, defaultOp.offset() - offset());
    index = storeInt(buf, index, lowOp);
    index = storeInt(buf, index, lowOp+targetsOp.length-1);
    for (int i=0; i<targetsOp.length; i++)
      index = storeInt(buf, index, targetsOp[i].offset() - offset());
    return index;
  }

  int size() {
    /* account for the instruction, 0-3 bytes of pad, 3 ints */
    int basic = ((offset() + 4) & ~3) - offset() + 12;
    /* Add 4*number of offsets */
    return basic + targetsOp.length*4;
  }


  InsnTableSwitch(int lowOp, InsnTarget defaultOp, 
		  InsnTarget[] targetsOp, int offset) {
    super(opc_tableswitch, offset);

    this.lowOp = lowOp;
    this.defaultOp = defaultOp; 
    this.targetsOp = targetsOp;

    if (defaultOp == null || targetsOp == null)
	throw new InsnError ("attempt to create an opc_tableswitch" +//NOI18N
			     " with invalid operands");//NOI18N
  }

  static InsnTableSwitch read (InsnReadEnv insnEnv, int myPC) {
    /* eat up any padding */
    int thisPC = myPC +1;
    for (int pads = ((thisPC + 3) & ~3) - thisPC; pads > 0; pads--)
      insnEnv.getByte();
    InsnTarget defaultTarget = insnEnv.getTarget(insnEnv.getInt() + myPC);
    int low = insnEnv.getInt();
    int high = insnEnv.getInt();
    InsnTarget[] offsets = new InsnTarget[high - low + 1];
    for (int i=0; i<offsets.length; i++)
      offsets[i] = insnEnv.getTarget(insnEnv.getInt() + myPC);
    return new InsnTableSwitch(low, defaultTarget,   offsets, myPC);
  }
}