001/*
002 * $RCSfile: CBlkQuantDataSrcEnc.java,v $
003 * $Revision: 1.1 $
004 * $Date: 2005/02/11 05:02:20 $
005 * $State: Exp $
006 *
007 * Class:                   CBlkQuantDataSrcEnc
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.
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 */
046
047
048package jj2000.j2k.quantization.quantizer;
049
050import jj2000.j2k.wavelet.analysis.*;
051import jj2000.j2k.entropy.encoder.*;
052import jj2000.j2k.wavelet.*;
053import jj2000.j2k.image.*;
054
055/**
056 * This interface defines a source of quantized wavelet coefficients and
057 * methods to transfer them in a code-block by code-block basis. In each call
058 * to 'getNextCodeBlock()' or 'getNextInternCodeBlock()' a new code-block is
059 * returned. The code-blocks are returned in no specific order.
060 *
061 * <p>This class is the source of data for the entropy coder. See the
062 * 'EntropyCoder' class.</p>
063 *
064 * <p>Code-block data is returned in sign-magnitude representation, instead of
065 * the normal two's complement one. Only integral types are used. The sign
066 * magnitude representation is more adequate for entropy coding. In sign
067 * magnitude representation, the most significant bit is used for the sign (0
068 * if positive, 1 if negative) and the magnitude of the coefficient is stored
069 * in the next M most significant bits. The rest of the bits (least
070 * significant bits) can contain a fractional value of the quantized
071 * coefficient. The number 'M' of magnitude bits is communicated in the
072 * 'magbits' member variable of the 'CBlkWTData'.</p>
073 *
074 * <p>Note that no more of one object may request data, otherwise one object
075 * would get some of the data and another one another part, in no defined
076 * manner.</p>
077 *
078 * @see ForwWTDataProps
079 * @see CBlkWTDataSrc
080 * @see Quantizer
081 * @see EntropyCoder
082 * */
083public interface CBlkQuantDataSrcEnc extends ForwWTDataProps {
084
085    /**
086     * Returns the next code-block in the current tile for the specified
087     * component, as a copy (see below). The order in which code-blocks are
088     * returned is not specified. However each code-block is returned only
089     * once and all code-blocks will be returned if the method is called 'N'
090     * times, where 'N' is the number of code-blocks in the tile. After all
091     * the code-blocks have been returned for the current tile calls to this
092     * method will return 'null'.
093     *
094     * <p>When changing the current tile (through 'setTile()' or 'nextTile()')
095     * this method will always return the first code-block, as if this method
096     * was never called before for the new current tile.</p>
097     *
098     * <p>The data returned by this method is always a copy of the internal
099     * data of this object, if any, and it can be modified "in place" without
100     * any problems after being returned. The 'offset' of the returned data is
101     * 0, and the 'scanw' is the same as the code-block width. See the
102     * 'CBlkWTData' class.</p>
103     *
104     * <p>The 'ulx' and 'uly' members of the returned 'CBlkWTData' object
105     * contain the coordinates of the top-left corner of the block, with
106     * respect to the tile, not the subband.</p>
107     *
108     * @param c The component for which to return the next code-block.
109     *
110     * @param cblk If non-null this object will be used to return the new
111     * code-block. If null a new one will be allocated and returned. If the
112     * "data" array of the object is non-null it will be reused, if possible,
113     * to return the data.
114     *
115     * @return The next code-block in the current tile for component 'c', or
116     * null if all code-blocks for the current tile have been returned.
117     *
118     * @see CBlkWTData
119     * */
120    public CBlkWTData getNextCodeBlock(int c,CBlkWTData cblk);
121
122    /**
123     * Returns the next code-block in the current tile for the specified
124     * component. The order in which code-blocks are returned is not
125     * specified. However each code-block is returned only once and all
126     * code-blocks will be returned if the method is called 'N' times, where
127     * 'N' is the number of code-blocks in the tile. After all the code-blocks
128     * have been returned for the current tile calls to this method will
129     * return 'null'.
130     *
131     * <p>When changing the current tile (through 'setTile()' or 'nextTile()')
132     * this method will always return the first code-block, as if this method
133     * was never called before for the new current tile.</p>
134     *
135     * <p>The data returned by this method can be the data in the internal
136     * buffer of this object, if any, and thus can not be modified by the
137     * caller. The 'offset' and 'scanw' of the returned data can be
138     * arbitrary. See the 'CBlkWTData' class.</p>
139     *
140     * <p>The 'ulx' and 'uly' members of the returned 'CBlkWTData' object
141     * contain the coordinates of the top-left corner of the block, with
142     * respect to the tile, not the subband.</p>
143     *
144     * @param c The component for which to return the next code-block.
145     *
146     * @param cblk If non-null this object will be used to return the new
147     * code-block. If null a new one will be allocated and returned. If the
148     * "data" array of the object is non-null it will be reused, if possible,
149     * to return the data.
150     *
151     * @return The next code-block in the current tile for component 'n', or
152     * null if all code-blocks for the current tile have been returned.
153     *
154     * @see CBlkWTData
155     * */
156    public CBlkWTData getNextInternCodeBlock(int c,CBlkWTData cblk);
157}