getopt.java

it is a basic java browser

/**
  * In GNU getopt, it is possible to change the string containg valid options
  * on the fly because it is passed as an argument to getopt() each time.  In
  * this version we do not pass the string on every call.  In order to allow
  * dynamic option string changing, this method is provided.
  *
  * @param optstring The new option string to use
  */
public void
setOptstring(String optstring)
{
  if (optstring.length() == 0)
    optstring = " ";

  this.optstring = optstring;
}

/**************************************************************************/

/**
  * optind it the index in ARGV of the next element to be scanned.
  * This is used for communication to and from the caller
  * and for communication between successive calls to `getopt'.
  *
  * When `getopt' returns -1, this is the index of the first of the
  * non-option elements that the caller should itself scan.
  *
  * Otherwise, `optind' communicates from one call to the next
  * how much of ARGV has been scanned so far.  
  */
public int
getOptind()
{
  return(optind);
}

/**************************************************************************/

/**
  * This method allows the optind index to be set manually.  Normally this
  * is not necessary (and incorrect usage of this method can lead to serious
  * lossage), but optind is a public symbol in GNU getopt, so this method 
  * was added to allow it to be modified by the caller if desired.
  *
  * @param optind The new value of optind
  */
public void
setOptind(int optind)
{
  this.optind = optind;
}

/**************************************************************************/

/**
  * Since in GNU getopt() the argument vector is passed back in to the
  * function every time, the caller can swap out argv on the fly.  Since
  * passing argv is not required in the Java version, this method allows
  * the user to override argv.  Note that incorrect use of this method can
  * lead to serious lossage.
  *
  * @param argv New argument list
  */
public void
setArgv(String[] argv)
{
  this.argv = argv;
}

/**************************************************************************/

/** 
  * For communication from `getopt' to the caller.
  * When `getopt' finds an option that takes an argument,
  * the argument value is returned here.
  * Also, when `ordering' is RETURN_IN_ORDER,
  * each non-option ARGV-element is returned here.
  * No set method is provided because setting this variable has no effect.
  */
public String
getOptarg()
{
  return(optarg);
}

/**************************************************************************/

/**
  * Normally Getopt will print a message to the standard error when an
  * invalid option is encountered.  This can be suppressed (or re-enabled)
  * by calling this method.  There is no get method for this variable 
  * because if you can't remember the state you set this to, why should I?
  */
public void
setOpterr(boolean opterr)
{
  this.opterr = opterr;
}

/**************************************************************************/

/**
  * When getopt() encounters an invalid option, it stores the value of that
  * option in optopt which can be retrieved with this method.  There is
  * no corresponding set method because setting this variable has no effect.
  */
public int
getOptopt()
{
  return(optopt);
}

/**************************************************************************/

/**
  * Returns the index into the array of long options (NOT argv) representing
  * the long option that was found.
  */
public int
getLongind()
{
  return(longind);
}

/**************************************************************************/

/**
  * Exchange the shorter segment with the far end of the longer segment.
  * That puts the shorter segment into the right place.
  * It leaves the longer segment in the right place overall,
  * but it consists of two parts that need to be swapped next.
  * This method is used by getopt() for argument permutation.
  */
protected void
exchange(String[] argv)
{
  int bottom = first_nonopt;
  int middle = last_nonopt;
  int top = optind;
  String tem;

  while (top > middle && middle > bottom)
    {
      if (top - middle > middle - bottom)
        {
          // Bottom segment is the short one. 
          int len = middle - bottom;
          int i;

          // Swap it with the top part of the top segment. 
          for (i = 0; i < len; i++)
            {
              tem = argv[bottom + i];
              argv[bottom + i] = argv[top - (middle - bottom) + i];
              argv[top - (middle - bottom) + i] = tem;
            }
          // Exclude the moved bottom segment from further swapping. 
          top -= len;
        }
      else
        {
          // Top segment is the short one.
          int len = top - middle;
          int i;

          // Swap it with the bottom part of the bottom segment. 
          for (i = 0; i < len; i++)
            {
              tem = argv[bottom + i];
              argv[bottom + i] = argv[middle + i];
              argv[middle + i] = tem;
            }
          // Exclude the moved top segment from further swapping. 
          bottom += len;
        }
    }

  // Update records for the slots the non-options now occupy. 

  first_nonopt += (optind - last_nonopt);
  last_nonopt = optind;
}

/**************************************************************************/

/**
  * Check to see if an option is a valid long option.  Called by getopt().
  * Put in a separate method because this needs to be done twice.  (The
  * C getopt authors just copy-pasted the code!).
  *
  * @param longind A buffer in which to store the 'val' field of found LongOpt
  *
  * @return Various things depending on circumstances
  */
protected int
checkLongOption()
{
  LongOpt pfound = null;
  int nameend;
  boolean ambig;
  boolean exact;
  
  longopt_handled = true;
  ambig = false;
  exact = false;
  longind = -1;

  nameend = nextchar.indexOf("=");
  if (nameend == -1)
    nameend = nextchar.length();
  
  // Test all lnog options for either exact match or abbreviated matches
  for (int i = 0; i < long_options.length; i++)
    {
      if (long_options[i].getName().startsWith(nextchar.substring(0, nameend)))
        {
          if (long_options[i].getName().equals(nextchar.substring(0, nameend)))
            {
              // Exact match found
              pfound = long_options[i];
              longind = i;
              exact = true;
              break;
            }
          else if (pfound == null)
            {
              // First nonexact match found
              pfound = long_options[i];
              longind = i;
            }
          else
            {
              // Second or later nonexact match found
              ambig = true;
            }
        }
    } // for
  
  // Print out an error if the option specified was ambiguous
  if (ambig && !exact)
    {
      if (opterr)
        {
          Object[] msgArgs = { progname, argv[optind] };
          System.err.println(MessageFormat.format(
                             _messages.getString("getopt.ambigious"), 
                             msgArgs));
        }

       nextchar = "";
       optopt = 0;
       ++optind;
 
       return('?');
    }
 
  if (pfound != null)
    {
      ++optind;
 
      if (nameend != nextchar.length())
        {
          if (pfound.has_arg != LongOpt.NO_ARGUMENT)
            {
              if (nextchar.substring(nameend).length() > 1)
                optarg = nextchar.substring(nameend+1);
              else
                optarg = "";
            }
          else
            {
              if (opterr)
                {
                  // -- option
                  if (argv[optind - 1].startsWith("--"))
                    {
                      Object[] msgArgs = { progname, pfound.name };
                      System.err.println(MessageFormat.format(
                                  _messages.getString("getopt.arguments1"), 
                                  msgArgs));
                    }
                  // +option or -option
                  else
                    {
                      Object[] msgArgs = { progname, new 
                               Character(argv[optind-1].charAt(0)).toString(),
                               pfound.name };
                      System.err.println(MessageFormat.format(
                               _messages.getString("getopt.arguments2"), 
                               msgArgs));
                    }
                 }
   
              nextchar = "";
              optopt = pfound.val;
   
              return('?');
            }
        } // if (nameend)
      else if (pfound.has_arg == LongOpt.REQUIRED_ARGUMENT)
        {
          if (optind < argv.length)
            {
               optarg = argv[optind];
               ++optind;
            }
          else
            {
              if (opterr)
                {
                  Object[] msgArgs = { progname, argv[optind-1] };
                  System.err.println(MessageFormat.format(
                                     _messages.getString("getopt.requires"), 
                                     msgArgs));
                }
   
              nextchar = "";
              optopt = pfound.val;
              if (optstring.charAt(0) == ':')
                return(':');
              else
                return('?');
            }
        } // else if (pfound)