/*

 * SpanDSP - a series of DSP components for telephony

 *

 * g722_decode.c - The ITU G.722 codec, decode part.

 *

 * Written by Steve Underwood <steveu@coppice.org>

 *

 * Copyright (C) 2005 Steve Underwood

 *

 *  Despite my general liking of the GPL, I place my own contributions 

 *  to this code in the public domain for the benefit of all mankind -

 *  even the slimy ones who might try to proprietize my work and use it

 *  to my detriment.

 *

 * Based in part on a single channel G.722 codec which is:

 *

 * Copyright (c) CMU 1993

 * Computer Science, Speech Group

 * Chengxiang Lu and Alex Hauptmann

 *

 * $Id: g722_decode.c 48661 2006-12-21 00:08:21Z mattf $

 */

/*! \file */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <stdio.h>

//#include <inttypes.h>

#include <memory.h>

#include <stdlib.h>

#if 0

#include <tgmath.h>

#endif

#include "g722.h"

#if !defined(FALSE)

#define FALSE 0

#endif

#if !defined(TRUE)

#define TRUE (!FALSE)

#endif

static  int16_t saturate(int32_t amp)

{

    int16_t amp16;

    /* Hopefully this is optimised for the common case - not clipping */

    amp16 = (int16_t) amp;

    if (amp == amp16)

        return amp16;

    if (amp > INT16_MAX)

        return  INT16_MAX;

    return  INT16_MIN;

}

/*- End of function --------------------------------------------------------*/

static void block4(g722_decode_state_t *s, int band, int d);

static void block4(g722_decode_state_t *s, int band, int d)

{

    int wd1;

    int wd2;

    int wd3;

    int i;

    /* Block 4, RECONS */

    s->band[band].d[0] = d;

    s->band[band].r[0] = saturate(s->band[band].s + d);

    /* Block 4, PARREC */

    s->band[band].p[0] = saturate(s->band[band].sz + d);

    /* Block 4, UPPOL2 */

    for (i = 0;  i < 3;  i++)

        s->band[band].sg[i] = s->band[band].p[i] >> 15;

    wd1 = saturate(s->band[band].a[1] << 2);

    wd2 = (s->band[band].sg[0] == s->band[band].sg[1])  ?  -wd1  :  wd1;

    if (wd2 > 32767)

        wd2 = 32767;

    wd3 = (s->band[band].sg[0] == s->band[band].sg[2])  ?  128  :  -128;

    wd3 += (wd2 >> 7);

    wd3 += (s->band[band].a[2]*32512) >> 15;

    if (wd3 > 12288)

        wd3 = 12288;

    else if (wd3 < -12288)

        wd3 = -12288;

    s->band[band].ap[2] = wd3;

    /* Block 4, UPPOL1 */

    s->band[band].sg[0] = s->band[band].p[0] >> 15;

    s->band[band].sg[1] = s->band[band].p[1] >> 15;

    wd1 = (s->band[band].sg[0] == s->band[band].sg[1])  ?  192  :  -192;

    wd2 = (s->band[band].a[1]*32640) >> 15;

    s->band[band].ap[1] = saturate(wd1 + wd2);

    wd3 = saturate(15360 - s->band[band].ap[2]);

    if (s->band[band].ap[1] > wd3)

        s->band[band].ap[1] = wd3;

    else if (s->band[band].ap[1] < -wd3)

        s->band[band].ap[1] = -wd3;

    /* Block 4, UPZERO */

    wd1 = (d == 0)  ?  0  :  128;

    s->band[band].sg[0] = d >> 15;

    for (i = 1;  i < 7;  i++)

    {

        s->band[band].sg[i] = s->band[band].d[i] >> 15;

        wd2 = (s->band[band].sg[i] == s->band[band].sg[0])  ?  wd1  :  -wd1;

        wd3 = (s->band[band].b[i]*32640) >> 15;

        s->band[band].bp[i] = saturate(wd2 + wd3);

    }

    /* Block 4, DELAYA */

    for (i = 6;  i > 0;  i--)

    {

        s->band[band].d[i] = s->band[band].d[i - 1];

        s->band[band].b[i] = s->band[band].bp[i];

    }

    for (i = 2;  i > 0;  i--)

    {

        s->band[band].r[i] = s->band[band].r[i - 1];

        s->band[band].p[i] = s->band[band].p[i - 1];

        s->band[band].a[i] = s->band[band].ap[i];

    }

    /* Block 4, FILTEP */

    wd1 = saturate(s->band[band].r[1] + s->band[band].r[1]);

    wd1 = (s->band[band].a[1]*wd1) >> 15;

    wd2 = saturate(s->band[band].r[2] + s->band[band].r[2]);

    wd2 = (s->band[band].a[2]*wd2) >> 15;

    s->band[band].sp = saturate(wd1 + wd2);

    /* Block 4, FILTEZ */

    s->band[band].sz = 0;

    for (i = 6;  i > 0;  i--)

    {

        wd1 = saturate(s->band[band].d[i] + s->band[band].d[i]);

        s->band[band].sz += (s->band[band].b[i]*wd1) >> 15;

    }

    s->band[band].sz = saturate(s->band[band].sz);

    /* Block 4, PREDIC */

    s->band[band].s = saturate(s->band[band].sp + s->band[band].sz);

}

/*- End of function --------------------------------------------------------*/

g722_decode_state_t *g722_decode_init(g722_decode_state_t *s, int rate, int options)

{

    if (s == NULL)

    {

        if ((s = (g722_decode_state_t *) malloc(sizeof(*s))) == NULL)

            return NULL;

    }

    memset(s, 0, sizeof(*s));

    if (rate == 48000)

        s->bits_per_sample = 6;

    else if (rate == 56000)

        s->bits_per_sample = 7;

    else

        s->bits_per_sample = 8;

    if ((options & G722_SAMPLE_RATE_8000))

        s->eight_k = TRUE;

    if ((options & G722_PACKED)  &&  s->bits_per_sample != 8)

        s->packed = TRUE;

    else

        s->packed = FALSE;

    s->band[0].det = 32;

    s->band[1].det = 8;

    return s;

}

/*- End of function --------------------------------------------------------*/

int g722_decode_release(g722_decode_state_t *s)

{

    free(s);

    return 0;

}

/*- End of function --------------------------------------------------------*/

int g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len)

{

    static const int wl[8] = {-60, -30, 58, 172, 334, 538, 1198, 3042 };

    static const int rl42[16] = {0, 7, 6, 5, 4, 3, 2, 1, 7, 6, 5, 4, 3,  2, 1, 0 };

    static const int ilb[32] =

    {

        2048, 2093, 2139, 2186, 2233, 2282, 2332,

        2383, 2435, 2489, 2543, 2599, 2656, 2714,

        2774, 2834, 2896, 2960, 3025, 3091, 3158,

        3228, 3298, 3371, 3444, 3520, 3597, 3676,

        3756, 3838, 3922, 4008

    };

    static const int wh[3] = {0, -214, 798};

    static const int rh2[4] = {2, 1, 2, 1};

    static const int qm2[4] = {-7408, -1616,  7408,   1616};

    static const int qm4[16] = 

    {

              0, -20456, -12896,  -8968, 

          -6288,  -4240,  -2584,  -1200,

          20456,  12896,   8968,   6288,

           4240,   2584,   1200,      0

    };

    static const int qm5[32] =

    {

           -280,   -280, -23352, -17560,

         -14120, -11664,  -9752,  -8184,

          -6864,  -5712,  -4696,  -3784,

          -2960,  -2208,  -1520,   -880,

          23352,  17560,  14120,  11664,

           9752,   8184,   6864,   5712,

           4696,   3784,   2960,   2208,

           1520,    880,    280,   -280

    };

    static const int qm6[64] =

    {

           -136,   -136,   -136,   -136,

         -24808, -21904, -19008, -16704,

         -14984, -13512, -12280, -11192,

         -10232,  -9360,  -8576,  -7856,

          -7192,  -6576,  -6000,  -5456,

          -4944,  -4464,  -4008,  -3576,

          -3168,  -2776,  -2400,  -2032,

          -1688,  -1360,  -1040,   -728,

          24808,  21904,  19008,  16704,

          14984,  13512,  12280,  11192,

          10232,   9360,   8576,   7856,

           7192,   6576,   6000,   5456,

           4944,   4464,   4008,   3576,

           3168,   2776,   2400,   2032,

           1688,   1360,   1040,    728,

            432,    136,   -432,   -136

    };

    static const int qmf_coeffs[12] =

    {

           3,  -11,   12,   32, -210,  951, 3876, -805,  362, -156,   53,  -11,

    };

    int dlowt;

    int rlow;

    int ihigh;

    int dhigh;

    int rhigh;

    int xout1;

    int xout2;

    int wd1;

    int wd2;

    int wd3;

    int code;

    int outlen;

    int i;

    int j;

    outlen = 0;

    rhigh = 0;

    for (j = 0;  j < len;  )

    {

        if (s->packed)

        {

            /* Unpack the code bits */

            if (s->in_bits < s->bits_per_sample)

            {

                s->in_buffer |= (g722_data[j++] << s->in_bits);

                s->in_bits += 8;

            }

            code = s->in_buffer & ((1 << s->bits_per_sample) - 1);

            s->in_buffer >>= s->bits_per_sample;

            s->in_bits -= s->bits_per_sample;

        }

        else

        {

            code = g722_data[j++];

        }

        switch (s->bits_per_sample)

        {

        default:

        case 8:

            wd1 = code & 0x3F;

            ihigh = (code >> 6) & 0x03;

            wd2 = qm6[wd1];

            wd1 >>= 2;

            break;

        case 7:

            wd1 = code & 0x1F;

            ihigh = (code >> 5) & 0x03;

            wd2 = qm5[wd1];

            wd1 >>= 1;

            break;

        case 6:

            wd1 = code & 0x0F;

            ihigh = (code >> 4) & 0x03;

            wd2 = qm4[wd1];

            break;

        }

        /* Block 5L, LOW BAND INVQBL */

        wd2 = (s->band[0].det*wd2) >> 15;

        /* Block 5L, RECONS */

        rlow = s->band[0].s + wd2;

        /* Block 6L, LIMIT */

        if (rlow > 16383)

            rlow = 16383;

        else if (rlow < -16384)

            rlow = -16384;

        /* Block 2L, INVQAL */

        wd2 = qm4[wd1];

        dlowt = (s->band[0].det*wd2) >> 15;

        /* Block 3L, LOGSCL */

        wd2 = rl42[wd1];

        wd1 = (s->band[0].nb*127) >> 7;

        wd1 += wl[wd2];

        if (wd1 < 0)

            wd1 = 0;

        else if (wd1 > 18432)

            wd1 = 18432;

        s->band[0].nb = wd1;

        /* Block 3L, SCALEL */

        wd1 = (s->band[0].nb >> 6) & 31;

        wd2 = 8 - (s->band[0].nb >> 11);

        wd3 = (wd2 < 0)  ?  (ilb[wd1] << -wd2)  :  (ilb[wd1] >> wd2);

        s->band[0].det = wd3 << 2;

        block4(s, 0, dlowt);

        if (!s->eight_k)

        {

            /* Block 2H, INVQAH */

            wd2 = qm2[ihigh];

            dhigh = (s->band[1].det*wd2) >> 15;

            /* Block 5H, RECONS */

            rhigh = dhigh + s->band[1].s;

            /* Block 6H, LIMIT */

            if (rhigh > 16383)

                rhigh = 16383;

            else if (rhigh < -16384)

                rhigh = -16384;

            /* Block 2H, INVQAH */

            wd2 = rh2[ihigh];

            wd1 = (s->band[1].nb*127) >> 7;

            wd1 += wh[wd2];

            if (wd1 < 0)

                wd1 = 0;

            else if (wd1 > 22528)

                wd1 = 22528;

            s->band[1].nb = wd1;

            /* Block 3H, SCALEH */

            wd1 = (s->band[1].nb >> 6) & 31;

            wd2 = 10 - (s->band[1].nb >> 11);

            wd3 = (wd2 < 0)  ?  (ilb[wd1] << -wd2)  :  (ilb[wd1] >> wd2);

            s->band[1].det = wd3 << 2;

            block4(s, 1, dhigh);

        }

        if (s->itu_test_mode)

        {

            amp[outlen++] = (int16_t) (rlow << 1);

            amp[outlen++] = (int16_t) (rhigh << 1);

        }

        else

        {

            if (s->eight_k)

            {

                amp[outlen++] = (int16_t) rlow;

            }

            else

            {

                /* Apply the receive QMF */

                for (i = 0;  i < 22;  i++)

                    s->x[i] = s->x[i + 2];

                s->x[22] = rlow + rhigh;

                s->x[23] = rlow - rhigh;

                xout1 = 0;

                xout2 = 0;

                for (i = 0;  i < 12;  i++)

                {

                    xout2 += s->x[2*i]*qmf_coeffs[i];

                    xout1 += s->x[2*i + 1]*qmf_coeffs[11 - i];

                }

                amp[outlen++] = (int16_t) (xout1 >> 12);

                amp[outlen++] = (int16_t) (xout2 >> 12);

            }

        }

    }

    return outlen;

}

/*- End of function --------------------------------------------------------*/

/*- End of file ------------------------------------------------------------*/