/*
* $RCSfile: CodestreamWriter.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:02 $
* $State: Exp $
*
* Class: CodestreamWriter
*
* Description: Interface for writing bit streams
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Rapha�l Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askel�f (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, F�lix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
* */
package jj2000.j2k.codestream.writer;
import java.io.*;
/**
* This is the abstract class for writing to a bit stream. Data is
* written in packets, each packet having a head and a body. The
* bit stream always has a maximum number of bytes that can be written
* to it. After that many number of bytes no more data is written to
* the bit stream but the number of bytes is counted so that the value
* returned by getMaxAvailableBytes() is negative. If the number of
* bytes is unlimited a ridicoulosly large value, such as
* Integer.MAX_VALUE, is equivalent.
*
* <P>Data may be written to the bit stream in sumulation mode. When in
* simulation mode no data is written to the bit stream but the
* resulting number of bytes is calculated and returned (although it
* is not accounted in the bit stream). This can be used in rate
* control loops.
*
* <P>Implementing classes should write the header of the bit stream
* before writing any packets. The bit stream header should be written
* with the aid of the HeaderEncoder class.
*
* @see HeaderEncoder
* */
public abstract class CodestreamWriter {
/** The number of bytes already written to the bit stream */
protected int ndata=0;
/** The maximum number of bytes that can be written to the
* bit stream */
protected int maxBytes;
/**
* Allocates this object and initializes the maximum numner of
* bytes.
*
* @param mb The maximum number of bytes that can be written to
* the bit stream.
* */
protected CodestreamWriter(int mb) {
maxBytes = mb;
}
/**
* Returns the number of bytes remaining available in the bit stream. This
* is the maximum allowed number of bytes minus the number of bytes that
* have already been written to the bit stream. If more bytes have been
* written to the bit stream than the maximum number of allowed bytes,
* then a negative value is returned.
*
* @return The number of bytes remaining available in the bit stream.
* */
public abstract int getMaxAvailableBytes();
/**
* Returns the current length of the entire bit stream.
*
* @return the current length of the bit stream
* */
public abstract int getLength();
/**
* Writes a packet head to the bit stream and returns the number of bytes
* used by this header. It returns the total number of bytes that the
* packet head takes in the bit stream. If in simulation mode then no data
* is written to the bit stream but the number of bytes is
* calculated. This can be used for iterative rate allocation.
*
* <P>If the length of the data that is to be written to the bit stream is
* more than the space left (as returned by getMaxAvailableBytes()) only
* the data that does not exceed the allowed length is written, the rest
* is discarded. However the value returned by the method is the total
* length of the packet, as if all of it was written to the bit stream.
*
* <P>If the bit stream header has not been commited yet and 'sim' is
* false, then the bit stream header is automatically commited (see
* commitBitstreamHeader() method) before writting the packet.
*
* @param head The packet head data.
*
* @param hlen The number of bytes in the packet head.
*
* @param sim Simulation mode flag. If true nothing is written to the bit
* stream, but the number of bytes that would be written is returned.
*
* @param sop Start of packet header marker flag. This flag indicates
* whether or not SOP markers should be written. If true, SOP markers
* should be written, if false, they should not.
*
* @param eph End of Packet Header marker flag. This flag indicates
* whether or not EPH markers should be written. If true, EPH markers
* should be written, if false, they should not.
*
* @return The number of bytes spent by the packet head.
*
* @exception IOException If an I/O error occurs while writing to the
* output stream.
*
* @see #commitBitstreamHeader
* */
public abstract int writePacketHead(byte head[],int hlen,boolean sim,
boolean sop, boolean eph)
throws IOException;
/**
* Writes a packet body to the bit stream and returns the number of bytes
* used by this body .If in simulation mode then no data is written to the
* bit stream but the number of bytes is calculated. This can be used for
* iterative rate allocation.
*
* <P>If the length of the data that is to be written to the bit stream is
* more than the space left (as returned by getMaxAvailableBytes()) only
* the data that does not exceed the allowed length is written, the rest
* is discarded. However the value returned by the method is the total
* length of the packet body , as if all of it was written to the bit
* stream.
*
* @param body The packet body data.
*
* @param blen The number of bytes in the packet body.
*
* @param sim Simulation mode flag. If true nothing is written to the bit
* stream, but the number of bytes that would be written is returned.
*
* @param roiInPkt Whether or not there is ROI information in this packet
*
* @param roiLen Number of byte to read in packet body to get all the ROI
* information
*
* @return The number of bytes spent by the packet body.
*
* @exception IOException If an I/O error occurs while writing to
* the output stream.
*
* @see #commitBitstreamHeader
* */
public abstract int writePacketBody(byte body[],int blen,boolean sim,
boolean roiInPkt, int roiLen)
throws IOException;
/**
* Closes the underlying resource (file, stream, network connection,
* etc.). After a CodestreamWriter is closed no more data can be written
* to it.
*
* @exception IOException If an I/O error occurs while closing the
* resource.
* */
public abstract void close() throws IOException;
/**
* Writes the header data to the bit stream, if it has not been already
* done. In some implementations this method can be called only once, and
* an IllegalArgumentException is thrown if called more than once.
*
* @exception IOException If an I/O error occurs while writing the data.
*
* @exception IllegalArgumentException If this method has already been
* called.
* */
public abstract void commitBitstreamHeader(HeaderEncoder he)
throws IOException;
/**
* Gives the offset of the end of last packet containing ROI information
*
* @return End of last ROI packet
* */
public abstract int getOffLastROIPkt();
}