/*
 * $RCSfile: StdDequantizer.java,v $
 * $Revision: 1.1 $
 * $Date: 2005/02/11 05:02:19 $
 * $State: Exp $
 *
 * Class:                   StdDequantizer
 *
 * Description:             Scalar deadzone dequantizer that returns integers
 *                          or floats.
 *                          This is a merger of the ScalarDZDeqInt and
 *                          ScalarDZDeqFloat classes by Joel Askelof and Diego
 *                          Santa Cruz.
 *
 *
 *
 * 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.quantization.dequantizer;

import jj2000.j2k.wavelet.synthesis.*;
import jj2000.j2k.entropy.decoder.*;
import jj2000.j2k.quantization.*;
import jj2000.j2k.codestream.*;
import jj2000.j2k.entropy.*;
import jj2000.j2k.decoder.*;
import jj2000.j2k.image.*;
import jj2000.j2k.io.*;

import java.io.*;

/**
 * This class implements a scalar dequantizer with deadzone. The output can be
 * either integer ('int') or floating-point ('float') data. The dequantization
 * step sizes and other parameters are taken from a StdDequantizerParams
 * class, which inherits from DequantizerParams.
 *
 * <P>Sign magnitude representation is used (instead of two's complement) for
 * the input data. The most significant bit is used for the sign (0 if
 * positive, 1 if negative). Then the magnitude of the quantized coefficient
 * is stored in the next most significat bits. The most significant magnitude
 * bit corresponds to the most significant bit-plane and so on.
 *
 * <P>When reversible quantization is used, this class only converts between
 * the sign-magnitude representation and the integer (or eventually
 * fixed-point) output, since there is no true quantization.
 *
 * <P>The output data is fixed-point two's complement for 'int' output and
 * floating-point for 'float' output. The type of output and the number number
 * of fractional bits for 'int' output are defined at the constructor. Each
 * component may have a different number of fractional bits.
 *
 * <P>The reconstruction levels used by the dequantizer are exactly what is
 * received from the entropy decoder. It is assumed that the entropy decoder
 * always returns codewords that are midways in the decoded intervals. In this
 * way the dequantized values will always lie midways in the quantization
 * intervals.
 * */
public class StdDequantizer extends Dequantizer {

    /** The quantizer type spec */
    private QuantTypeSpec qts;

    /** The quantizer step sizes  spec */
    private QuantStepSizeSpec qsss;

    /** The number of guard bits spec */
    private GuardBitsSpec gbs;

    /** The decoding parameters of the dequantizer */
    private StdDequantizerParams params;

    /** The 'DataBlkInt' object used to request data, used when output data is
     * not int */
    private DataBlkInt inblk;

    /** Type of the current output data */
    private int outdtype;

    /**
     * Initializes the source of compressed data. And sets the number of range
     * bits and fraction bits and receives the parameters for the dequantizer.
     *
     * @param src From where to obtain the quantized data.
     *
     * @param rb The number of "range bits" (bitdepth) for each component
     * (must be the "range bits" of the un-transformed components). For a
     * definition of "range bits" see the getNomRangeBits() method.
     *
     * @param qts The quantizer type spec
     *
     * @param qsss The dequantizer step sizes spec
     *
     * @see Dequantizer#getNomRangeBits
     *
     * @exception IllegalArgumentException Thrown if 'outdt' is neither
     * TYPE_FLOAT nor TYPE_INT, or if 'param' specify reversible quantization
     * and 'outdt' is not TYPE_INT or 'fp' has non-zero values, or if 'outdt'
     * is TYPE_FLOAT and 'fp' has non-zero values.
     * */
    public StdDequantizer(CBlkQuantDataSrcDec src,int[] utrb,
                               DecoderSpecs decSpec){
        super(src,utrb,decSpec);

        if(utrb.length != src.getNumComps()){
            throw new IllegalArgumentException("Invalid rb argument");
        }
        this.qsss = decSpec.qsss;
        this.qts = decSpec.qts;
        this.gbs = decSpec.gbs;
    }

    /**
     * Returns the position of the fixed point in the output data for the
     * specified component. 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. If the output data is 'float' then 0
     * is always returned.
     *
     * <P><u>Note:</u> Fractional bits are no more supported by JJ2000.
     *
     * @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){
        return 0;
    }

    /**
     * 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 final DataBlk getCodeBlock(int c, int m, int n, SubbandSyn sb,
                                        DataBlk cblk) {
        return getInternCodeBlock(c,m,n,sb,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 final
        DataBlk getInternCodeBlock(int c, int m, int n, SubbandSyn sb,
                                     DataBlk cblk) {
        // This method is declared final since getNextCodeBlock() relies on
        // the actual implementation of this method.
        int j,jmin,k;
        int temp;
        float step;
        int shiftBits;
        int magBits;
        int[] outiarr,inarr;
        float[] outfarr;
        int w,h;
        boolean reversible = qts.isReversible(tIdx,c);
        boolean derived = qts.isDerived(tIdx,c);
        StdDequantizerParams
            params = (StdDequantizerParams)qsss.getTileCompVal(tIdx,c);
        int G = ((Integer)gbs.getTileCompVal(tIdx,c)).intValue();

        outdtype = cblk.getDataType();

        if (reversible && outdtype!=DataBlk.TYPE_INT) {
            throw new IllegalArgumentException("Reversible quantizations "+
                                               "must use int data");
        }

        // To get compiler happy
        outiarr = null;
        outfarr = null;
        inarr = null;

        // Get source data and initialize output DataBlk object.
        switch (outdtype) {
        case DataBlk.TYPE_INT:
            // With int data we can use the same DataBlk object to get the
            // data from the source and return the dequantized data, and we
            // can also work "in place" (i.e. same buffer).
            cblk = src.getCodeBlock(c,m,n,sb,cblk);
            // Input and output arrays are the same
            outiarr = (int[]) cblk.getData();
            break;
        case DataBlk.TYPE_FLOAT:
            // With float data we must use a different DataBlk objects to get
            // the data from the source and to return the dequantized data.
            inblk = (DataBlkInt) src.getInternCodeBlock(c,m,n,sb,inblk);
            inarr = inblk.getDataInt();
            if (cblk == null) {
                cblk = new DataBlkFloat();
            }
            // Copy the attributes of the CodeBlock object
            cblk.ulx = inblk.ulx;
            cblk.uly = inblk.uly;
            cblk.w = inblk.w;
            cblk.h = inblk.h;
            cblk.offset = 0;
            cblk.scanw = cblk.w;
            cblk.progressive = inblk.progressive;
            // Get output data array and check its size
            outfarr = (float[]) cblk.getData();
            if (outfarr == null || outfarr.length < cblk.w*cblk.h) {
                outfarr = new float[cblk.w*cblk.h];
                cblk.setData(outfarr);
            }
            break;
        }

        magBits = sb.magbits;

        // Calculate quantization step and number of magnitude bits
        // depending on reversibility and derivedness and perform
        // inverse quantization
        if(reversible){
            shiftBits=31-magBits;
            // For int data Inverse quantization happens "in-place". The input
            // array has an offset of 0 and scan width equal to the code-block
            // width.
            for (j=outiarr.length-1; j>=0; j--) {
                temp = outiarr[j]; // input array is same as output one
                outiarr[j]=(temp >= 0) ? (temp>>shiftBits) :
                    -((temp&0x7FFFFFFF)>>shiftBits);
            }
        }
        else{// Not reversible
            if(derived){
                // Max resolution level
                int mrl = src.getSynSubbandTree(getTileIdx(),c).resLvl;
                step=params.nStep[0][0]*
                    (1L<<(rb[c]+sb.anGainExp+mrl-sb.level));
            }
            else{
                step=params.nStep[sb.resLvl][sb.sbandIdx]*
                    (1L<<(rb[c]+sb.anGainExp));
            }
            shiftBits=31-magBits;

            // Adjust step to the number of shiftBits
            step /= (1<<shiftBits);

            switch (outdtype) {
            case DataBlk.TYPE_INT:
                // For int data Inverse quantization happens "in-place". The
                // input array has an offset of 0 and scan width equal to the
                // code-block width.
                for (j=outiarr.length-1; j>=0; j--) {
                    temp = outiarr[j]; // input array is same as output one
                    outiarr[j] = (int)(((float)((temp >= 0) ? temp :
                                                -(temp&0x7FFFFFFF)))*step);
                }
                break;
            case DataBlk.TYPE_FLOAT:
                // For float data the inverse quantization can not happen
                // "in-place".
                w = cblk.w;
                h = cblk.h;
                for (j=w*h-1, k=inblk.offset+(h-1)*inblk.scanw+w-1,
                         jmin = w*(h-1); j>=0; jmin -= w) {
                    for (; j>=jmin; k--, j--) {
                        temp = inarr[k];
                        outfarr[j] = ((float)((temp >= 0) ? temp :
                                              -(temp&0x7FFFFFFF)))*step;
                    }
                    // Jump to beggining of previous line in input
                    k -= inblk.scanw - w;
                }
                break;
            }
        }
        // Return the output code-block
        return cblk;
    }
}