/* ***** BEGIN LICENSE BLOCK *****
    Version: RCSL 1.0/RPSL 1.0

    Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved.

    The contents of this file, and the files included with this file, are
    subject to the current version of the RealNetworks Public Source License
    Version 1.0 (the "RPSL") available at
    http://www.helixcommunity.org/content/rpsl unless you have licensed
    the file under the RealNetworks Community Source License Version 1.0
    (the "RCSL") available at http://www.helixcommunity.org/content/rcsl,
    in which case the RCSL will apply. You may also obtain the license terms
    directly from RealNetworks.  You may not use this file except in
    compliance with the RPSL or, if you have a valid RCSL with RealNetworks
    applicable to this file, the RCSL.  Please see the applicable RPSL or
    RCSL for the rights, obligations and limitations governing use of the
    contents of the file.

    This file is part of the Helix DNA Technology. RealNetworks is the
    developer of the Original Code and owns the copyrights in the portions
    it created.

    This file, and the files included with this file, is distributed and made
    available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
    EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES,
    INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS
    FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.

    Technology Compatibility Kit Test Suite(s) Location:
      http://www.helixcommunity.org/content/tck

    Contributor(s):

 * ***** END LICENSE BLOCK ***** */

/**************************************************************************************
    Fixed-point MP3 decoder
    Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
    June 2003

    dequant.c - dequantization, stereo processing (intensity, mid-side), short-block
                 coefficient reordering
 **************************************************************************************/

#include "coder.h"
#include "assembly.h"

/**************************************************************************************
    Function:    Dequantize

    Description: dequantize coefficients, decode stereo, reorder short blocks
                  (one granule-worth)

    Inputs:      MP3DecInfo structure filled by UnpackFrameHeader(), UnpackSideInfo(),
                  UnpackScaleFactors(), and DecodeHuffman() (for this granule)
                index of current granule

    Outputs:     dequantized and reordered coefficients in hi->huffDecBuf
                  (one granule-worth, all channels), format = Q26
                operates in-place on huffDecBuf but also needs di->workBuf
                updated hi->nonZeroBound index for both channels

    Return:      0 on success, -1 if null input pointers

    Notes:       In calling output Q(DQ_FRACBITS_OUT), we assume an implicit bias
                  of 2^15. Some (floating-point) reference implementations factor this
                  into the 2^(0.25 * gain) scaling explicitly. But to avoid precision
                  loss, we don't do that. Instead take it into account in the final
                  round to PCM (>> by 15 less than we otherwise would have).
                Equivalently, we can think of the dequantized coefficients as
                  Q(DQ_FRACBITS_OUT - 15) with no implicit bias.
 **************************************************************************************/
int Dequantize(MP3DecInfo *mp3DecInfo, int gr) {
    int i, ch, nSamps, mOut[2];
    FrameHeader *fh;
    SideInfo *si;
    ScaleFactorInfo *sfi;
    HuffmanInfo *hi;
    DequantInfo *di;
    CriticalBandInfo *cbi;

    /* validate pointers */
    if (!mp3DecInfo || !mp3DecInfo->FrameHeaderPS || !mp3DecInfo->SideInfoPS || !mp3DecInfo->ScaleFactorInfoPS ||
            !mp3DecInfo->HuffmanInfoPS || !mp3DecInfo->DequantInfoPS) {
        return -1;
    }

    fh = (FrameHeader *)(mp3DecInfo->FrameHeaderPS);

    /* si is an array of up to 4 structs, stored as gr0ch0, gr0ch1, gr1ch0, gr1ch1 */
    si = (SideInfo *)(mp3DecInfo->SideInfoPS);
    sfi = (ScaleFactorInfo *)(mp3DecInfo->ScaleFactorInfoPS);
    hi = (HuffmanInfo *)mp3DecInfo->HuffmanInfoPS;
    di = (DequantInfo *)mp3DecInfo->DequantInfoPS;
    cbi = di->cbi;
    mOut[0] = mOut[1] = 0;

    /* dequantize all the samples in each channel */
    for (ch = 0; ch < mp3DecInfo->nChans; ch++) {
        hi->gb[ch] = DequantChannel(hi->huffDecBuf[ch], di->workBuf, &hi->nonZeroBound[ch], fh,
                                    &si->sis[gr][ch], &sfi->sfis[gr][ch], &cbi[ch]);
    }

    /*  joint stereo processing assumes one guard bit in input samples
        it's extremely rare not to have at least one gb, so if this is the case
         just make a pass over the data and clip to [-2^30+1, 2^30-1]
        in practice this may never happen
    */
    if (fh->modeExt && (hi->gb[0] < 1 || hi->gb[1] < 1)) {
        for (i = 0; i < hi->nonZeroBound[0]; i++) {
            if (hi->huffDecBuf[0][i] < -0x3fffffff) {
                hi->huffDecBuf[0][i] = -0x3fffffff;
            }
            if (hi->huffDecBuf[0][i] >  0x3fffffff) {
                hi->huffDecBuf[0][i] =  0x3fffffff;
            }
        }
        for (i = 0; i < hi->nonZeroBound[1]; i++) {
            if (hi->huffDecBuf[1][i] < -0x3fffffff) {
                hi->huffDecBuf[1][i] = -0x3fffffff;
            }
            if (hi->huffDecBuf[1][i] >  0x3fffffff) {
                hi->huffDecBuf[1][i] =  0x3fffffff;
            }
        }
    }

    /* do mid-side stereo processing, if enabled */
    if (fh->modeExt >> 1) {
        if (fh->modeExt & 0x01) {
            /* intensity stereo enabled - run mid-side up to start of right zero region */
            if (cbi[1].cbType == 0) {
                nSamps = fh->sfBand->l[cbi[1].cbEndL + 1];
            } else {
                nSamps = 3 * fh->sfBand->s[cbi[1].cbEndSMax + 1];
            }
        } else {
            /* intensity stereo disabled - run mid-side on whole spectrum */
            nSamps = MAX(hi->nonZeroBound[0], hi->nonZeroBound[1]);
        }
        MidSideProc(hi->huffDecBuf, nSamps, mOut);
    }

    /* do intensity stereo processing, if enabled */
    if (fh->modeExt & 0x01) {
        nSamps = hi->nonZeroBound[0];
        if (fh->ver == MPEG1) {
            IntensityProcMPEG1(hi->huffDecBuf, nSamps, fh, &sfi->sfis[gr][1], di->cbi,
                               fh->modeExt >> 1, si->sis[gr][1].mixedBlock, mOut);
        } else {
            IntensityProcMPEG2(hi->huffDecBuf, nSamps, fh, &sfi->sfis[gr][1], di->cbi, &sfi->sfjs,
                               fh->modeExt >> 1, si->sis[gr][1].mixedBlock, mOut);
        }
    }

    /* adjust guard bit count and nonZeroBound if we did any stereo processing */
    if (fh->modeExt) {
        hi->gb[0] = CLZ(mOut[0]) - 1;
        hi->gb[1] = CLZ(mOut[1]) - 1;
        nSamps = MAX(hi->nonZeroBound[0], hi->nonZeroBound[1]);
        hi->nonZeroBound[0] = nSamps;
        hi->nonZeroBound[1] = nSamps;
    }

    /* output format Q(DQ_FRACBITS_OUT) */
    return 0;
}
