/*
 * $RCSfile: CBlkWTDataSrcDec.java,v $
 * $Revision: 1.1 $
 * $Date: 2005-02-11 05:02:31 $
 * $State: Exp $
 *
 * Class:                   CBlkWTDataSrcDec
 *
 * Description:             Interface that define methods for trasnfer of WT
 *                          data in a code-block basis (decoder side).
 *
 *
 *
 * COPYRIGHT:
 *
 * This software module was originally developed by Raphaël Grosbois and
 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
 * Bouchard, Félix 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.wavelet.synthesis;

import jj2000.j2k.image.*;
import jj2000.j2k.wavelet.*;

/**
 * This abstract class defines methods to transfer wavelet data in a
 * code-block by code-block basis, for the decoder side. In each call to
 * 'getCodeBlock()' or 'getInternCodeBlock()' a new code-block is
 * returned. The code-blocks are returned in no specific order.
 *
 * <P>This class is the source of data, in general, for the inverse wavelet
 * transforms. See the 'InverseWT' class.
 *
 * @see InvWTData
 *
 * @see WaveletTransform
 *
 * @see jj2000.j2k.quantization.dequantizer.CBlkQuantDataSrcDec
 *
 * @see InverseWT
 * */
public interface CBlkWTDataSrcDec extends InvWTData {

    /**
     * Returns the number of bits, referred to as the "range bits",
     * corresponding to the nominal range of the data in the specified
     * component.
     *
     * <P>The returned value corresponds to the nominal dynamic range of the
     * reconstructed image data, not of the wavelet coefficients
     * themselves. This is because different subbands have different gains and
     * thus different nominal ranges. To have an idea of the nominal range in
     * each subband the subband analysis gain value from the subband tree
     * structure, returned by the 'getSubbandTree()' method, can be used. See
     * the 'Subband' class for more details.
     *
     * <P>If this number is <i>b</b> then for unsigned data the nominal range
     * is between 0 and 2^b-1, and for signed data it is between -2^(b-1) and
     * 2^(b-1)-1.
     *
     * @param c The index of the component
     *
     * @return The number of bits corresponding to the nominal range of the
     * data.
     *
     * @see Subband
     * */
    public int getNomRangeBits(int c);

    /**
     * Returns the position of the fixed point in the specified component, or
     * equivalently the number of fractional bits. This is the position of the
     * least significant integral (i.e. non-fractional) bit, which is
     * equivalent to the number of fractional bits. For instance, for
     * fixed-point values with 2 fractional bits, 2 is returned. For
     * floating-point data this value does not apply and 0 should be
     * returned. Position 0 is the position of the least significant bit in
     * the data.
     *
     * @param c The index of the component.
     *
     * @return The position of the fixed-point, which is the same as the
     * number of fractional bits. For floating-point data 0 is returned.
     * */
     public int getFixedPoint(int c);

    /**
     * Returns the specified code-block in the current tile for the specified
     * component, as a copy (see below).
     *
     * <P>The returned code-block may be progressive, which is indicated by
     * the 'progressive' variable of the returned 'DataBlk' object. If a
     * code-block is progressive it means that in a later request to this
     * method for the same code-block it is possible to retrieve data which is
     * a better approximation, since meanwhile more data to decode for the
     * code-block could have been received. If the code-block is not
     * progressive then later calls to this method for the same code-block
     * will return the exact same data values.
     *
     * <P>The data returned by this method is always a copy of the internal
     * data of this object, if any, and it can be modified "in place" without
     * any problems after being returned. The 'offset' of the returned data is
     * 0, and the 'scanw' is the same as the code-block width. See the
     * 'DataBlk' class.
     *
     * @param c The component for which to return the next code-block.
     *
     * @param m The vertical index of the code-block to return,
     * in the specified subband.
     *
     * @param n The horizontal index of the code-block to return,
     * in the specified subband.
     *
     * @param sb The subband in which the code-block to return is.
     *
     * @param cblk If non-null this object will be used to return the new
     * code-block. If null a new one will be allocated and returned. If the
     * "data" array of the object is non-null it will be reused, if possible,
     * to return the data.
     *
     * @return The next code-block in the current tile for component 'n', or
     * null if all code-blocks for the current tile have been returned.
     *
     * @see DataBlk
     * */
    public DataBlk getCodeBlock(int c, int m, int n, SubbandSyn sb,
                                DataBlk cblk);

    /**
     * Returns the specified code-block in the current tile for the specified
     * component (as a reference or copy).
     *
     * <P>The returned code-block may be progressive, which is indicated by
     * the 'progressive' variable of the returned 'DataBlk'
     * object. If a code-block is progressive it means that in a later request
     * to this method for the same code-block it is possible to retrieve data
     * which is a better approximation, since meanwhile more data to decode
     * for the code-block could have been received. If the code-block is not
     * progressive then later calls to this method for the same code-block
     * will return the exact same data values.
     *
     * <P>The data returned by this method can be the data in the internal
     * buffer of this object, if any, and thus can not be modified by the
     * caller. The 'offset' and 'scanw' of the returned data can be
     * arbitrary. See the 'DataBlk' class.
     *
     * @param c The component for which to return the next code-block.
     *
     * @param m The vertical index of the code-block to return, in the
     * specified subband.
     *
     * @param n The horizontal index of the code-block to return, in the
     * specified subband.
     *
     * @param sb The subband in which the code-block to return is.
     *
     * @param cblk If non-null this object will be used to return the new
     * code-block. If null a new one will be allocated and returned. If the
     * "data" array of the object is non-null it will be reused, if possible,
     * to return the data.
     *
     * @return The next code-block in the current tile for component 'n', or
     * null if all code-blocks for the current tile have been returned.
     *
     * @see DataBlk
     * */
    public DataBlk getInternCodeBlock(int c, int m, int n, SubbandSyn sb,
                                        DataBlk cblk);
}
