001/*
002 * $RCSfile: CBlkQuantDataSrcDec.java,v $
003 * $Revision: 1.1 $
004 * $Date: 2005/02/11 05:02:18 $
005 * $State: Exp $
006 *
007 * Class:                   CBlkQuantDataSrcDec
008 *
009 * Description:             Interface that defines a source of
010 *                          quantized wavelet data to be transferred in a
011 *                          code-block by code-block basis (decoder side).
012 *
013 *
014 *
015 * COPYRIGHT:
016 *
017 * This software module was originally developed by Raphaël Grosbois and
018 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
019 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
020 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
021 * Centre France S.A) in the course of development of the JPEG2000
022 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
023 * software module is an implementation of a part of the JPEG 2000
024 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
025 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
026 * Partners) agree not to assert against ISO/IEC and users of the JPEG
027 * 2000 Standard (Users) any of their rights under the copyright, not
028 * including other intellectual property rights, for this software module
029 * with respect to the usage by ISO/IEC and Users of this software module
030 * or modifications thereof for use in hardware or software products
031 * claiming conformance to the JPEG 2000 Standard. Those intending to use
032 * this software module in hardware or software products are advised that
033 * their use may infringe existing patents. The original developers of
034 * this software module, JJ2000 Partners and ISO/IEC assume no liability
035 * for use of this software module or modifications thereof. No license
036 * or right to this software module is granted for non JPEG 2000 Standard
037 * conforming products. JJ2000 Partners have full right to use this
038 * software module for his/her own purpose, assign or donate this
039 * software module to any third party and to inhibit third parties from
040 * using this software module for non JPEG 2000 Standard conforming
041 * products. This copyright notice must be included in all copies or
042 * derivative works of this software module.
043 *
044 * Copyright (c) 1999/2000 JJ2000 Partners.
045 * */
046package jj2000.j2k.quantization.dequantizer;
047
048import jj2000.j2k.entropy.decoder.EntropyDecoder;
049import jj2000.j2k.image.DataBlk;
050import jj2000.j2k.wavelet.synthesis.CBlkWTDataSrcDec;
051import jj2000.j2k.wavelet.synthesis.InvWTData;
052import jj2000.j2k.wavelet.synthesis.SubbandSyn;
053
054/**
055 * This interface defines a source of quantized wavelet coefficients and
056 * methods to transfer them in a code-block by code-block basis, fro the
057 * decoder side. In each call to 'getCodeBlock()' or 'getInternCodeBlock()' a
058 * new code-block is returned.
059 *
060 * <P>This class is the source of data for the dequantizer. See the
061 * 'Dequantizer' class.
062 *
063 * <P>Code-block data is returned in sign-magnitude representation, instead of
064 * the normal two's complement one. Only integral types are used. The sign
065 * magnitude representation is more adequate for entropy coding. In sign
066 * magnitude representation, the most significant bit is used for the sign (0
067 * if positive, 1 if negative) and the magnitude of the coefficient is stored
068 * in the next M most significant bits. The rest of the bits (least
069 * significant bits) can contain a fractional value of the quantized
070 * coefficient. The number 'M' of magnitude bits is communicated in the
071 * 'magbits' member variable of the 'CBlkWTData'.
072 *
073 * @see InvWTData
074 * @see CBlkWTDataSrcDec
075 * @see Dequantizer
076 * @see EntropyDecoder
077 * */
078public interface CBlkQuantDataSrcDec extends InvWTData {
079
080    /**
081     * Returns the specified code-block in the current tile for the specified
082     * component, as a copy (see below).
083     *
084     * <p>The returned code-block may be progressive, which is indicated by
085     * the 'progressive' variable of the returned 'DataBlk' object. If a
086     * code-block is progressive it means that in a later request to this
087     * method for the same code-block it is possible to retrieve data which is
088     * a better approximation, since meanwhile more data to decode for the
089     * code-block could have been received. If the code-block is not
090     * progressive then later calls to this method for the same code-block
091     * will return the exact same data values.</p>
092     *
093     * <p>The data returned by this method is always a copy of the internal
094     * data of this object, if any, and it can be modified "in place" without
095     * any problems after being returned. The 'offset' of the returned data is
096     * 0, and the 'scanw' is the same as the code-block width. See the
097     * 'DataBlk' class.</p>
098     *
099     * <p>The 'ulx' and 'uly' members of the returned 'DataBlk' object contain
100     * the coordinates of the top-left corner of the block, with respect to
101     * the tile, not the subband.</p>
102     *
103     * @param c The component for which to return the next code-block.
104     *
105     * @param m The vertical index of the code-block to return, in the
106     * specified subband.
107     *
108     * @param n The horizontal index of the code-block to return, in the
109     * specified subband.
110     *
111     * @param sb The subband in which the code-block to return is.
112     *
113     * @param cblk If non-null this object will be used to return the new
114     * code-block. If null a new one will be allocated and returned. If the
115     * "data" array of the object is non-null it will be reused, if possible,
116     * to return the data.
117     *
118     * @return The next code-block in the current tile for component 'n', or
119     * null if all code-blocks for the current tile have been returned.
120     *
121     * @see DataBlk
122     * */
123    public DataBlk getCodeBlock(int c,int m,int n,SubbandSyn sb,DataBlk cblk);
124
125    /**
126     * Returns the specified code-block in the current tile for the specified
127     * component (as a reference or copy).
128     *
129     * <p>The returned code-block may be progressive, which is indicated by
130     * the 'progressive' variable of the returned 'DataBlk' object. If a
131     * code-block is progressive it means that in a later request to this
132     * method for the same code-block it is possible to retrieve data which is
133     * a better approximation, since meanwhile more data to decode for the
134     * code-block could have been received. If the code-block is not
135     * progressive then later calls to this method for the same code-block
136     * will return the exact same data values.</p>
137     *
138     * <p>The data returned by this method can be the data in the internal
139     * buffer of this object, if any, and thus can not be modified by the
140     * caller. The 'offset' and 'scanw' of the returned data can be
141     * arbitrary. See the 'DataBlk' class.</p>
142     *
143     * <p>The 'ulx' and 'uly' members of the returned 'DataBlk' object contain
144     * the coordinates of the top-left corner of the block, with respect to
145     * the tile, not the subband.</p>
146     *
147     * @param c The component for which to return the next code-block.
148     *
149     * @param m The vertical index of the code-block to return, in the
150     * specified subband.
151     *
152     * @param n The horizontal index of the code-block to return, in the
153     * specified subband.
154     *
155     * @param sb The subband in which the code-block to return is.
156     *
157     * @param cblk If non-null this object will be used to return the new
158     * code-block. If null a new one will be allocated and returned. If the
159     * "data" array of the object is non-null it will be reused, if possible,
160     * to return the data.
161     *
162     * @return The next code-block in the current tile for component 'n', or
163     * null if all code-blocks for the current tile have been returned.
164     *
165     * @see DataBlk
166     * */
167    public DataBlk getInternCodeBlock(int c,int m,int n,SubbandSyn sb,
168                                      DataBlk cblk);
169}