/*
 * @(#)EncapsulationUtility.java	1.23 03/12/19
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.corba.se.impl.ior;

import java.util.List;
import java.util.LinkedList;
import java.util.Iterator;

import org.omg.IOP.TAG_INTERNET_IOP ;

import org.omg.CORBA_2_3.portable.OutputStream ;
import org.omg.CORBA_2_3.portable.InputStream ;

import com.sun.corba.se.spi.ior.TaggedComponent ;
import com.sun.corba.se.spi.ior.Identifiable ;
import com.sun.corba.se.spi.ior.IdentifiableFactoryFinder ;
import com.sun.corba.se.spi.ior.WriteContents ;

import com.sun.corba.se.spi.orb.ORB ;

import com.sun.corba.se.impl.ior.FreezableList ;

import com.sun.corba.se.impl.encoding.CDROutputStream ;
import com.sun.corba.se.impl.encoding.EncapsOutputStream ;
import com.sun.corba.se.impl.encoding.EncapsInputStream ;

/**
 * This static utility class contains various utility methods for reading and
 * writing CDR encapsulations.
 *
 * @author Ken Cavanaugh
 */
public class EncapsulationUtility 
{
    private EncapsulationUtility()
    {
    }

    /** Read the count from is, then read count Identifiables from
     * is using the factory.  Add each constructed Identifiable to container.
     */
    public static void readIdentifiableSequence( List container,
	IdentifiableFactoryFinder finder, InputStream istr) 
    {
	int count = istr.read_long() ;
	for (int ctr = 0; ctr<count; ctr++) {
	    int id = istr.read_long() ;
	    Identifiable obj = finder.create( id, istr ) ;
	    container.add( obj ) ;
	}
    }

    /** Write all Identifiables that we contain to os.  The total
     * length must be written before this method is called.
     */
    public static  void writeIdentifiableSequence( List container, OutputStream os) 
    {
	os.write_long( container.size() ) ;
	Iterator iter = container.iterator() ;
	while (iter.hasNext()) {
	    Identifiable obj = (Identifiable)( iter.next() ) ;
	    os.write_long( obj.getId() ) ;
	    obj.write( os ) ;
	}
    }

    /** Helper method that is used to extract data from an output
    * stream and write the data to another output stream.  Defined
    * as static so that it can be used in another class.
    */
    static public void writeOutputStream( OutputStream dataStream,
	OutputStream os ) 
    {
	byte[] data = ((CDROutputStream)dataStream).toByteArray() ;
	os.write_long( data.length ) ;
	os.write_octet_array( data, 0, data.length ) ;
    }

    /** Helper method to read the octet array from is, deencapsulate it, 
    * and return
    * as another InputStream.  This must be called inside the
    * constructor of a derived class to obtain the correct stream
    * for unmarshalling data.
    */
    static public InputStream getEncapsulationStream( InputStream is )
    {
	byte[] data = readOctets( is ) ;
	EncapsInputStream result = new EncapsInputStream( is.orb(), data, 
	    data.length ) ;
	result.consumeEndian() ;
	return result ;
    } 

    /** Helper method that reads an octet array from an input stream.
    * Defined as static here so that it can be used in another class.
    */
    static public byte[] readOctets( InputStream is ) 
    {
	int len = is.read_ulong() ;
	byte[] data = new byte[len] ;
	is.read_octet_array( data, 0, len ) ;
	return data ;
    }

    static public void writeEncapsulation( WriteContents obj,
	OutputStream os )
    {
	EncapsOutputStream out = new EncapsOutputStream( (ORB)os.orb() ) ;

	out.putEndian() ;

	obj.writeContents( out ) ;

	writeOutputStream( out, os ) ;
    }
}