001/*
002 * $RCSfile: EntropyDecoder.java,v $
003 * $Revision: 1.1 $
004 * $Date: 2005/02/11 05:02:06 $
005 * $State: Exp $
006 *
007 * Class:                   EntropyDecoder
008 *
009 * Description:             The abstract class for all entropy decoders.
010 *
011 *
012 *
013 * COPYRIGHT:
014 *
015 * This software module was originally developed by Raphaël Grosbois and
016 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
017 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
018 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
019 * Centre France S.A) in the course of development of the JPEG2000
020 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
021 * software module is an implementation of a part of the JPEG 2000
022 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
023 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
024 * Partners) agree not to assert against ISO/IEC and users of the JPEG
025 * 2000 Standard (Users) any of their rights under the copyright, not
026 * including other intellectual property rights, for this software module
027 * with respect to the usage by ISO/IEC and Users of this software module
028 * or modifications thereof for use in hardware or software products
029 * claiming conformance to the JPEG 2000 Standard. Those intending to use
030 * this software module in hardware or software products are advised that
031 * their use may infringe existing patents. The original developers of
032 * this software module, JJ2000 Partners and ISO/IEC assume no liability
033 * for use of this software module or modifications thereof. No license
034 * or right to this software module is granted for non JPEG 2000 Standard
035 * conforming products. JJ2000 Partners have full right to use this
036 * software module for his/her own purpose, assign or donate this
037 * software module to any third party and to inhibit third parties from
038 * using this software module for non JPEG 2000 Standard conforming
039 * products. This copyright notice must be included in all copies or
040 * derivative works of this software module.
041 *
042 * Copyright (c) 1999/2000 JJ2000 Partners.
043 * */
044package jj2000.j2k.entropy.decoder;
045
046import jj2000.j2k.quantization.dequantizer.CBlkQuantDataSrcDec;
047import jj2000.j2k.wavelet.synthesis.MultiResImgData;
048import jj2000.j2k.wavelet.synthesis.MultiResImgDataAdapter;
049import jj2000.j2k.wavelet.synthesis.SubbandSyn;
050
051/**
052 * This is the abstract class from which all entropy decoders must
053 * inherit. This class implements the 'MultiResImgData', therefore it has the
054 * concept of a current tile and all operations are performed on the current
055 * tile.
056 *
057 * <P>Default implementations of the methods in 'MultiResImgData' are provided
058 * through the 'MultiResImgDataAdapter' abstract class.
059 *
060 * <P>Sign magnitude representation is used (instead of two's complement) for
061 * the output data. The most significant bit is used for the sign (0 if
062 * positive, 1 if negative). Then the magnitude of the quantized coefficient
063 * is stored in the next most significat bits. The most significant magnitude
064 * bit corresponds to the most significant bit-plane and so on.
065 *
066 * @see MultiResImgData
067 * @see MultiResImgDataAdapter
068 * */
069public abstract class EntropyDecoder extends MultiResImgDataAdapter
070    implements CBlkQuantDataSrcDec {
071
072    /** The prefix for entropy decoder optiojns: 'C' */
073    public final static char OPT_PREFIX = 'C';
074
075    /** The list of parameters that is accepted by the entropy
076     * decoders. They start with 'C'. */
077    private final static String [][] pinfo = {
078        {"Cverber", "[true|false]",
079         "Specifies if the entropy decoder should be verbose about detected "+
080         "errors. If 'true' a message is printed whenever an error is detected.",
081         "true"},
082        {"Cer", "[true|false]",
083         "Specifies if error detection should be performed by the entropy "+
084         "decoder engine. If errors are detected they will be concealed and "+
085         "the resulting distortion will be less important. Note that errors "+
086         "can only be detected if the encoder that generated the data "+
087         "included error resilience information.", "true"},
088    };
089
090    /** The bit stream transport from where to get the compressed data
091     * (the source) */
092    protected CodedCBlkDataSrcDec src;
093
094    /**
095     * Initializes the source of compressed data.
096     *
097     * @param src From where to obtain the compressed data.
098     * */
099    public EntropyDecoder(CodedCBlkDataSrcDec src) {
100        super(src);
101        this.src = src;
102    }
103
104    /**
105     * Returns the subband tree, for the specified tile-component. This method
106     * returns the root element of the subband tree structure, see Subband and
107     * SubbandSyn. The tree comprises all the available resolution levels.
108     *
109     * <P>The number of magnitude bits ('magBits' member variable) for
110     * each subband is not initialized.
111     *
112     * @param t The index of the tile, from 0 to T-1.
113     *
114     * @param c The index of the component, from 0 to C-1.
115     *
116     * @return The root of the tree structure.
117     * */
118
119    public SubbandSyn getSynSubbandTree(int t,int c) {
120        return src.getSynSubbandTree(t,c);
121    }
122
123    /**
124     * Returns the horizontal code-block partition origin. Allowable values
125     * are 0 and 1, nothing else.
126     * */
127    public int getCbULX() {
128        return src.getCbULX();
129    }
130
131    /**
132     * Returns the vertical code-block partition origin. Allowable values are
133     * 0 and 1, nothing else.
134     * */
135    public int getCbULY() {
136        return src.getCbULY();
137    }
138
139
140    /**
141     * Returns the parameters that are used in this class and
142     * implementing classes. It returns a 2D String array. Each of the
143     * 1D arrays is for a different option, and they have 3
144     * elements. The first element is the option name, the second one
145     * is the synopsis and the third one is a long description of what
146     * the parameter is. The synopsis or description may be 'null', in
147     * which case it is assumed that there is no synopsis or
148     * description of the option, respectively. Null may be returned
149     * if no options are supported.
150     *
151     * @return the options name, their synopsis and their explanation,
152     * or null if no options are supported.
153     * */
154    public static String[][] getParameterInfo() {
155        return pinfo;
156    }
157
158}