/*
* LrangeCmd.java
*
* Copyright (c) 1997 Cornell University.
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
* 
* Included in SQLite3 port to C# for use in testharness only;  2008 Noah B Hart
*
* RCS @(#) $Id: LrangeCmd.java,v 1.2 2000/03/17 23:31:30 mo Exp $
*
*/
using System;
namespace tcl.lang
{

  /// <summary> This class implements the built-in "lrange" command in Tcl.</summary>

  class LrangeCmd : Command
  {
    /// <summary> See Tcl user documentation for details.</summary>
    /// <exception cref=""> TclException If incorrect number of arguments.
    /// </exception>

    public TCL.CompletionCode cmdProc( Interp interp, TclObject[] argv )
    {
      if ( argv.Length != 4 )
      {
        throw new TclNumArgsException( interp, 1, argv, "list first last" );
      }

      int size = TclList.getLength( interp, argv[1] );
      int first;
      int last;

      first = Util.getIntForIndex( interp, argv[2], size - 1 );
      last = Util.getIntForIndex( interp, argv[3], size - 1 );

      if ( last < 0 )
      {
        interp.resetResult();
        return TCL.CompletionCode.RETURN;
      }
      if ( first >= size )
      {
        interp.resetResult();
        return TCL.CompletionCode.RETURN;
      }
      if ( first <= 0 && last >= size )
      {
        interp.setResult( argv[1] );
        return TCL.CompletionCode.RETURN;
      }

      if ( first < 0 )
      {
        first = 0;
      }
      if ( first >= size )
      {
        first = size - 1;
      }
      if ( last < 0 )
      {
        last = 0;
      }
      if ( last >= size )
      {
        last = size - 1;
      }
      if ( first > last )
      {
        interp.resetResult();
        return TCL.CompletionCode.RETURN;
      }

      TclObject list = TclList.newInstance();

      list.preserve();
      try
      {
        for ( int i = first; i <= last; i++ )
        {
          TclList.append( interp, list, TclList.index( interp, argv[1], i ) );
        }
        interp.setResult( list );
      }
      finally
      {
        list.release();
      }
      return TCL.CompletionCode.RETURN;
    }
  }
}