/* ***** BEGIN LICENSE BLOCK *****
    Source last modified: $Id: noiseless.c,v 1.1 2005/02/26 01:47:35 jrecker Exp $

    Portions Copyright (c) 1995-2005 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 (the "RPSL") available at
    http://www.helixcommunity.org/content/rpsl unless you have licensed
    the file under the current version of the RealNetworks Community
    Source License (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
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    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
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    Technology Compatibility Kit Test Suite(s) Location:
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    Contributor(s):

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

/**************************************************************************************
    Fixed-point HE-AAC decoder
    Jon Recker (jrecker@real.com)
    February 2005

    noiseless.c - decode channel info, scalefactors, quantized coefficients,
                   scalefactor band codebook, and TNS coefficients from bitstream
 **************************************************************************************/

#include "coder.h"

//#include "profile.h"

//#define PROFILE_START(x)
//#define PROFILE_END()

/**************************************************************************************
    Function:    DecodeICSInfo

    Description: decode individual channel stream info

    Inputs:      BitStreamInfo struct pointing to start of ICS info
                  (14496-3, table 4.4.6)
                sample rate index

    Outputs:     updated icsInfo struct

    Return:      none
 **************************************************************************************/
/* __attribute__ ((section (".data"))) */ void DecodeICSInfo(BitStreamInfo *bsi, ICSInfo *icsInfo, int sampRateIdx) {
    int sfb, g, mask;

    icsInfo->icsResBit =      GetBits(bsi, 1);
    icsInfo->winSequence =    GetBits(bsi, 2);
    icsInfo->winShape =       GetBits(bsi, 1);
    if (icsInfo->winSequence == 2) {
        /* short block */
        icsInfo->maxSFB =     GetBits(bsi, 4);
        icsInfo->sfGroup =    GetBits(bsi, 7);
        icsInfo->numWinGroup =    1;
        icsInfo->winGroupLen[0] = 1;
        mask = 0x40;	/* start with bit 6 */
        for (g = 0; g < 7; g++) {
            if (icsInfo->sfGroup & mask)	{
                icsInfo->winGroupLen[icsInfo->numWinGroup - 1]++;
            } else {
                icsInfo->numWinGroup++;
                icsInfo->winGroupLen[icsInfo->numWinGroup - 1] = 1;
            }
            mask >>= 1;
        }
    } else {
        /* long block */
        icsInfo->maxSFB =               GetBits(bsi, 6);
        icsInfo->predictorDataPresent = GetBits(bsi, 1);
        if (icsInfo->predictorDataPresent) {
            icsInfo->predictorReset =   GetBits(bsi, 1);
            if (icsInfo->predictorReset) {
                icsInfo->predictorResetGroupNum = GetBits(bsi, 5);
            }
            for (sfb = 0; sfb < MIN(icsInfo->maxSFB, predSFBMax[sampRateIdx]); sfb++) {
                icsInfo->predictionUsed[sfb] = GetBits(bsi, 1);
            }
        }
        icsInfo->numWinGroup = 1;
        icsInfo->winGroupLen[0] = 1;
    }
}

/**************************************************************************************
    Function:    DecodeSectionData

    Description: decode section data (scale factor band groupings and
                  associated Huffman codebooks)

    Inputs:      BitStreamInfo struct pointing to start of ICS info
                  (14496-3, table 4.4.25)
                window sequence (short or long blocks)
                number of window groups (1 for long blocks, 1-8 for short blocks)
                max coded scalefactor band

    Outputs:     index of Huffman codebook for each scalefactor band in each section

    Return:      none

    Notes:       sectCB, sectEnd, sfbCodeBook, ordered by window groups for short blocks
 **************************************************************************************/
/* __attribute__ ((section (".data"))) */ static void DecodeSectionData(BitStreamInfo *bsi, int winSequence, int numWinGrp, int maxSFB, unsigned char *sfbCodeBook) {
    int g, cb, sfb;
    int sectLen, sectLenBits, sectLenIncr, sectEscapeVal;

    sectLenBits = (winSequence == 2 ? 3 : 5);
    sectEscapeVal = (1 << sectLenBits) - 1;

    for (g = 0; g < numWinGrp; g++) {
        sfb = 0;
        while (sfb < maxSFB) {
            cb = GetBits(bsi, 4);	/* next section codebook */
            sectLen = 0;
            do {
                sectLenIncr = GetBits(bsi, sectLenBits);
                sectLen += sectLenIncr;
            } while (sectLenIncr == sectEscapeVal);

            sfb += sectLen;
            while (sectLen--) {
                *sfbCodeBook++ = (unsigned char)cb;
            }
        }
        ASSERT(sfb == maxSFB);
    }
}

/**************************************************************************************
    Function:    DecodeOneScaleFactor

    Description: decode one scalefactor using scalefactor Huffman codebook

    Inputs:      BitStreamInfo struct pointing to start of next coded scalefactor

    Outputs:     updated BitstreamInfo struct

    Return:      one decoded scalefactor, including index_offset of -60
 **************************************************************************************/
static int DecodeOneScaleFactor(BitStreamInfo *bsi) {
    int nBits, val;
    unsigned int bitBuf;

    /* decode next scalefactor from bitstream */
    bitBuf = GetBitsNoAdvance(bsi, huffTabScaleFactInfo.maxBits) << (32 - huffTabScaleFactInfo.maxBits);
    //PROFILE_START("DecodeHuffmanScalar");
    nBits = DecodeHuffmanScalar(huffTabScaleFact, &huffTabScaleFactInfo, bitBuf, &val);
    AdvanceBitstream(bsi, nBits);
    //PROFILE_END();
    return val;
}

/**************************************************************************************
    Function:    DecodeScaleFactors

    Description: decode scalefactors, PNS energy, and intensity stereo weights

    Inputs:      BitStreamInfo struct pointing to start of ICS info
                  (14496-3, table 4.4.26)
                number of window groups (1 for long blocks, 1-8 for short blocks)
                max coded scalefactor band
                global gain (starting value for differential scalefactor coding)
                index of Huffman codebook for each scalefactor band in each section

    Outputs:     decoded scalefactor for each section

    Return:      none

    Notes:       sfbCodeBook, scaleFactors ordered by window groups for short blocks
                for section with codebook 13, scaleFactors buffer has decoded PNS
                  energy instead of regular scalefactor
                for section with codebook 14 or 15, scaleFactors buffer has intensity
                  stereo weight instead of regular scalefactor
 **************************************************************************************/
/* __attribute__ ((section (".data"))) */ static void DecodeScaleFactors(BitStreamInfo *bsi, int numWinGrp, int maxSFB, int globalGain,
        unsigned char *sfbCodeBook, short *scaleFactors) {
    int g, sfbCB, nrg, npf, val, sf, is;

    /* starting values for differential coding */
    sf = globalGain;
    is = 0;
    nrg = globalGain - 90 - 256;
    npf = 1;

    for (g = 0; g < numWinGrp * maxSFB; g++) {
        sfbCB = *sfbCodeBook++;

        if (sfbCB  == 14 || sfbCB == 15) {
            /* intensity stereo - differential coding */
            val = DecodeOneScaleFactor(bsi);
            is += val;
            *scaleFactors++ = (short)is;
        } else if (sfbCB == 13) {
            /* PNS - first energy is directly coded, rest are Huffman coded (npf = noise_pcm_flag) */
            if (npf) {
                val = GetBits(bsi, 9);
                npf = 0;
            } else {
                val = DecodeOneScaleFactor(bsi);
            }
            nrg += val;
            *scaleFactors++ = (short)nrg;
        } else if (sfbCB >= 1 && sfbCB <= 11) {
            /* regular (non-zero) region - differential coding */
            val = DecodeOneScaleFactor(bsi);
            sf += val;
            *scaleFactors++ = (short)sf;
        } else {
            /* inactive scalefactor band if codebook 0 */
            *scaleFactors++ = 0;
        }
    }
}

/**************************************************************************************
    Function:    DecodePulseInfo

    Description: decode pulse information

    Inputs:      BitStreamInfo struct pointing to start of pulse info
                  (14496-3, table 4.4.7)

    Outputs:     updated PulseInfo struct

    Return:      none
 **************************************************************************************/
/* __attribute__ ((section (".data"))) */ static void DecodePulseInfo(BitStreamInfo *bsi, PulseInfo *pi) {
    int i;

    pi->numPulse = GetBits(bsi, 2) + 1;		/* add 1 here */
    pi->startSFB = GetBits(bsi, 6);
    for (i = 0; i < pi->numPulse && i < MAX_PULSES; i++) {
        pi->offset[i] = GetBits(bsi, 5);
        pi->amp[i] = GetBits(bsi, 4);
    }
}

/**************************************************************************************
    Function:    DecodeTNSInfo

    Description: decode TNS filter information

    Inputs:      BitStreamInfo struct pointing to start of TNS info
                  (14496-3, table 4.4.27)
                window sequence (short or long blocks)

    Outputs:     updated TNSInfo struct
                buffer of decoded (signed) TNS filter coefficients

    Return:      none
 **************************************************************************************/
static const signed char sgnMask[3] = {0x02,  0x04,  0x08};
static const signed char negMask[3] = {~0x03, ~0x07, ~0x0f};

static void DecodeTNSInfo(BitStreamInfo *bsi, int winSequence, TNSInfo *ti, signed char *tnsCoef) {
    int i, w, f, coefBits, compress;
    signed char c, s, n;

    unsigned char *filtLength, *filtOrder, *filtDir;

    filtLength = ti->length;
    filtOrder =  ti->order;
    filtDir =    ti->dir;

    if (winSequence == 2) {
        /* short blocks */
        for (w = 0; w < NWINDOWS_SHORT; w++) {
            ti->numFilt[w] = GetBits(bsi, 1);
            if (ti->numFilt[w]) {
                ti->coefRes[w] = GetBits(bsi, 1) + 3;
                *filtLength =    GetBits(bsi, 4);
                *filtOrder =     GetBits(bsi, 3);
                if (*filtOrder) {
                    *filtDir++ =      GetBits(bsi, 1);
                    compress =        GetBits(bsi, 1);
                    coefBits = (int)ti->coefRes[w] - compress;	/* 2, 3, or 4 */
                    s = sgnMask[coefBits - 2];
                    n = negMask[coefBits - 2];
                    for (i = 0; i < *filtOrder; i++) {
                        c = GetBits(bsi, coefBits);
                        if (c & s)	{
                            c |= n;
                        }
                        *tnsCoef++ = c;
                    }
                }
                filtLength++;
                filtOrder++;
            }
        }
    } else {
        /* long blocks */
        ti->numFilt[0] = GetBits(bsi, 2);
        if (ti->numFilt[0]) {
            ti->coefRes[0] = GetBits(bsi, 1) + 3;
        }
        for (f = 0; f < ti->numFilt[0]; f++) {
            *filtLength =      GetBits(bsi, 6);
            *filtOrder =       GetBits(bsi, 5);
            if (*filtOrder) {
                *filtDir++ =     GetBits(bsi, 1);
                compress =       GetBits(bsi, 1);
                coefBits = (int)ti->coefRes[0] - compress;	/* 2, 3, or 4 */
                s = sgnMask[coefBits - 2];
                n = negMask[coefBits - 2];
                for (i = 0; i < *filtOrder; i++) {
                    c = GetBits(bsi, coefBits);
                    if (c & s)	{
                        c |= n;
                    }
                    *tnsCoef++ = c;
                }
            }
            filtLength++;
            filtOrder++;
        }
    }
}

/*  bitstream field lengths for gain control data:
     gainBits[winSequence][0] = maxWindow (how many gain windows there are)
     gainBits[winSequence][1] = locBitsZero (bits for alocCode if window == 0)
     gainBits[winSequence][2] = locBits (bits for alocCode if window != 0)
*/
static const unsigned char gainBits[4][3] = {
    {1, 5, 5},  /* long */
    {2, 4, 2},  /* start */
    {8, 2, 2},  /* short */
    {2, 4, 5},  /* stop */
};

/**************************************************************************************
    Function:    DecodeGainControlInfo

    Description: decode gain control information (SSR profile only)

    Inputs:      BitStreamInfo struct pointing to start of gain control info
                  (14496-3, table 4.4.12)
                window sequence (short or long blocks)

    Outputs:     updated GainControlInfo struct

    Return:      none
 **************************************************************************************/
static void DecodeGainControlInfo(BitStreamInfo *bsi, int winSequence, GainControlInfo *gi) {
    int bd, wd, ad;
    int locBits, locBitsZero, maxWin;

    gi->maxBand = GetBits(bsi, 2);
    maxWin = (int)gainBits[winSequence][0];
    locBitsZero = (int)gainBits[winSequence][1];
    locBits = (int)gainBits[winSequence][2];

    for (bd = 1; bd <= gi->maxBand; bd++) {
        for (wd = 0; wd < maxWin; wd++) {
            gi->adjNum[bd][wd] = GetBits(bsi, 3);
            for (ad = 0; ad < gi->adjNum[bd][wd]; ad++) {
                gi->alevCode[bd][wd][ad] = GetBits(bsi, 4);
                gi->alocCode[bd][wd][ad] = GetBits(bsi, (wd == 0 ? locBitsZero : locBits));
            }
        }
    }
}

/**************************************************************************************
    Function:    DecodeICS

    Description: decode individual channel stream

    Inputs:      platform specific info struct
                BitStreamInfo struct pointing to start of individual channel stream
                  (14496-3, table 4.4.24)
                index of current channel

    Outputs:     updated section data, scale factor data, pulse data, TNS data,
                  and gain control data

    Return:      none
 **************************************************************************************/
static void DecodeICS(PSInfoBase *psi, BitStreamInfo *bsi, int ch) {
    int globalGain;
    ICSInfo *icsInfo;
    PulseInfo *pi;
    TNSInfo *ti;
    GainControlInfo *gi;

    icsInfo = (ch == 1 && psi->commonWin == 1) ? &(psi->icsInfo[0]) : &(psi->icsInfo[ch]);

    globalGain = GetBits(bsi, 8);
    if (!psi->commonWin) {
        DecodeICSInfo(bsi, icsInfo, psi->sampRateIdx);
    }

    DecodeSectionData(bsi, icsInfo->winSequence, icsInfo->numWinGroup, icsInfo->maxSFB, psi->sfbCodeBook[ch]);

    DecodeScaleFactors(bsi, icsInfo->numWinGroup, icsInfo->maxSFB, globalGain, psi->sfbCodeBook[ch], psi->scaleFactors[ch]);

    pi = &psi->pulseInfo[ch];
    pi->pulseDataPresent = GetBits(bsi, 1);
    if (pi->pulseDataPresent) {
        DecodePulseInfo(bsi, pi);
    }

    ti = &psi->tnsInfo[ch];
    ti->tnsDataPresent = GetBits(bsi, 1);
    if (ti->tnsDataPresent) {
        DecodeTNSInfo(bsi, icsInfo->winSequence, ti, ti->coef);
    }

    gi = &psi->gainControlInfo[ch];
    gi->gainControlDataPresent = GetBits(bsi, 1);
    if (gi->gainControlDataPresent) {
        DecodeGainControlInfo(bsi, icsInfo->winSequence, gi);
    }
}

/**************************************************************************************
    Function:    DecodeNoiselessData

    Description: decode noiseless data (side info and transform coefficients)

    Inputs:      valid AACDecInfo struct
                double pointer to buffer pointing to start of individual channel stream
                  (14496-3, table 4.4.24)
                pointer to bit offset
                pointer to number of valid bits remaining in buf
                index of current channel

    Outputs:     updated global gain, section data, scale factor data, pulse data,
                  TNS data, gain control data, and spectral data

    Return:      0 if successful, error code (< 0) if error
 **************************************************************************************/
int DecodeNoiselessData(AACDecInfo *aacDecInfo, unsigned char **buf, int *bitOffset, int *bitsAvail, int ch) {
    int bitsUsed;
    BitStreamInfo bsi;
    PSInfoBase *psi;
    ICSInfo *icsInfo;

    /* validate pointers */
    if (!aacDecInfo || !aacDecInfo->psInfoBase) {
        return ERR_AAC_NULL_POINTER;
    }
    psi = (PSInfoBase *)(aacDecInfo->psInfoBase);
    icsInfo = (ch == 1 && psi->commonWin == 1) ? &(psi->icsInfo[0]) : &(psi->icsInfo[ch]);

    SetBitstreamPointer(&bsi, (*bitsAvail + 7) >> 3, *buf);
    GetBits(&bsi, *bitOffset);

    DecodeICS(psi, &bsi, ch);

    if (icsInfo->winSequence == 2) {
        DecodeSpectrumShort(psi, &bsi, ch);
    } else {
        DecodeSpectrumLong(psi, &bsi, ch);
    }

    bitsUsed = CalcBitsUsed(&bsi, *buf, *bitOffset);
    *buf += ((bitsUsed + *bitOffset) >> 3);
    *bitOffset = ((bitsUsed + *bitOffset) & 0x07);
    *bitsAvail -= bitsUsed;

    aacDecInfo->sbDeinterleaveReqd[ch] = 0;
    aacDecInfo->tnsUsed |= psi->tnsInfo[ch].tnsDataPresent;	/* set flag if TNS used for any channel */

    return ERR_AAC_NONE;
}
