/*
 * 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 194722 2009-05-15 17:59:08Z russell $
 */

/*! \file */

#include <inttypes.h>
#include <stdlib.h>
#include <string.h>

#include "g722_enc_dec.h"
#include "g722_typedefs.h"

#if !defined(FALSE)
#define FALSE 0
#endif
#if !defined(TRUE)
#define TRUE (!FALSE)
#endif

#define PACKED_INPUT (0)
#define BITS_PER_SAMPLE (8)

#ifndef BUILD_FEATURE_G722_USE_INTRINSIC_SAT
static __inline int16_t __ssat16(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 > 0x7fff) {
    return 0x7fff;
  }
  return 0x8000;
}
/*- End of function --------------------------------------------------------*/
#else
static __inline int16_t __ssat16(int32_t val) {
  register int32_t res;
  __asm volatile("SSAT %0, #16, %1\n\t" : "=r"(res) : "r"(val) :);
  return (int16_t)res;
}
#endif

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

static void block4(g722_band_t *band, int d);

static void block4(g722_band_t *band, int d) {
  int wd1;
  int wd2;
  int wd3;
  int i;
  int sg[7];
  int ap1, ap2;
  int sg0, sgi;
  int sz;

  /* Block 4, RECONS */
  band->d[0] = d;
  band->r[0] = __ssat16(band->s + d);

  /* Block 4, PARREC */
  band->p[0] = __ssat16(band->sz + d);

  /* Block 4, UPPOL2 */
  for (i = 0; i < 3; i++) {
    sg[i] = band->p[i] >> 15;
  }
  wd1 = __ssat16(band->a[1] << 2);

  wd2 = (sg[0] == sg[1]) ? -wd1 : wd1;
  if (wd2 > 32767) {
    wd2 = 32767;
  }

  ap2 = (sg[0] == sg[2]) ? 128 : -128;
  ap2 += (wd2 >> 7);
  ap2 += (band->a[2] * 32512) >> 15;
  if (ap2 > 12288) {
    ap2 = 12288;
  } else if (ap2 < -12288) {
    ap2 = -12288;
  }
  band->ap[2] = ap2;

  /* Block 4, UPPOL1 */
  sg[0] = band->p[0] >> 15;
  sg[1] = band->p[1] >> 15;
  wd1 = (sg[0] == sg[1]) ? 192 : -192;
  wd2 = (band->a[1] * 32640) >> 15;

  ap1 = __ssat16(wd1 + wd2);
  wd3 = __ssat16(15360 - band->ap[2]);
  if (ap1 > wd3) {
    ap1 = wd3;
  } else if (ap1 < -wd3) {
    ap1 = -wd3;
  }
  band->ap[1] = ap1;

  /* Block 4, UPZERO */
  /* Block 4, FILTEZ */
  wd1 = (d == 0) ? 0 : 128;

  sg0 = sg[0] = d >> 15;
  for (i = 1; i < 7; i++) {
    sgi = band->d[i] >> 15;
    wd2 = (sgi == sg0) ? wd1 : -wd1;
    wd3 = (band->b[i] * 32640) >> 15;
    band->bp[i] = __ssat16(wd2 + wd3);
  }

  /* Block 4, DELAYA */
  sz = 0;
  for (i = 6; i > 0; i--) {
    int bi;

    band->d[i] = band->d[i - 1];
    bi = band->b[i] = band->bp[i];
    wd1 = __ssat16(band->d[i] + band->d[i]);
    sz += (bi * wd1) >> 15;
  }
  band->sz = sz;

  for (i = 2; i > 0; i--) {
    band->r[i] = band->r[i - 1];
    band->p[i] = band->p[i - 1];
    band->a[i] = band->ap[i];
  }

  /* Block 4, FILTEP */
  wd1 = __ssat16(band->r[1] + band->r[1]);
  wd1 = (band->a[1] * wd1) >> 15;
  wd2 = __ssat16(band->r[2] + band->r[2]);
  wd2 = (band->a[2] * wd2) >> 15;
  band->sp = __ssat16(wd1 + wd2);

  /* Block 4, PREDIC */
  band->s = __ssat16(band->sp + band->sz);
}
/*- End of function --------------------------------------------------------*/

g722_decode_state_t *g722_decode_init(g722_decode_state_t *s, unsigned int rate, int options) {
  if (s == NULL) {
#ifdef G722_SUPPORT_MALLOC
    if ((s = (g722_decode_state_t *)malloc(sizeof(*s))) == NULL)
#endif
      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;
  }
  s->dac_pcm = options & G722_FORMAT_DAC12;
  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 --------------------------------------------------------*/

static int16_t wl[8] = {-60, -30, 58, 172, 334, 538, 1198, 3042};
static int16_t rl42[16] = {0, 7, 6, 5, 4, 3, 2, 1, 7, 6, 5, 4, 3, 2, 1, 0};
static int16_t 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 int16_t wh[3] = {0, -214, 798};
static int16_t rh2[4] = {2, 1, 2, 1};
static int16_t qm2[4] = {-7408, -1616, 7408, 1616};
static int16_t qm4[16] = {0,     -20456, -12896, -8968, -6288, -4240, -2584, -1200,
                          20456, 12896,  8968,   6288,  4240,  2584,  1200,  0};
#if 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
};
#endif
static int16_t 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 int16_t qmf_coeffs_even[12] = {
        3, -11, 12, 32, -210, 951, 3876, -805, 362, -156, 53, -11,
};
static int16_t qmf_coeffs_odd[12] = {-11, 53, -156, 362, -805, 3876, 951, -210, 32, 12, -11, 3};

uint32_t g722_decode(g722_decode_state_t *s, int16_t amp[], const uint8_t g722_data[], int len,
                     uint16_t gain) {
  int dlowt;
  int rlow;
  int ihigh;
  int dhigh;
  int rhigh;
  int xout1;
  int xout2;
  int wd1;
  int wd2;
  int wd3;
  int code;
  uint32_t outlen;
  int i;
  int j;

  outlen = 0;
  rhigh = 0;

  for (j = 0; j < len;) {
#if PACKED_INPUT == 1
    /* 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++];
#endif

#if BITS_PER_SAMPLE == 8
    wd1 = code & 0x3F;
    ihigh = (code >> 6) & 0x03;
    wd2 = qm6[wd1];
    wd1 >>= 2;
#elif BITS_PER_SAMPLE == 7
    wd1 = code & 0x1F;
    ihigh = (code >> 5) & 0x03;
    wd2 = qm5[wd1];
    wd1 >>= 1;
#elif BITS_PER_SAMPLE == 6
    wd1 = code & 0x0F;
    ihigh = (code >> 4) & 0x03;
    wd2 = qm4[wd1];
#endif
    /* Block 5L, LOW BAND INVQBL */
    wd2 = (s->band[0].det * wd2) >> 15;
    /* Block 5L, RECONS */
    rlow = s->band[0].s + wd2;
    /* Block 6L, LIMIT */

    // ANDREA
    // rlow=ssat(rlow,2<<14)
    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->band[0], dlowt);

    /* 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 */

    // ANDREA
    // rhigh=ssat(rhigh,2<<14)

    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->band[1], dhigh);

    /* 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;

    // we should get PERF numbers for the following loop
    xout1 = 0;
    xout2 = 0;
    for (i = 0; i < 12; i++) {
      xout2 += s->x[2 * i] * qmf_coeffs_even[i];
      xout1 += s->x[2 * i + 1] * qmf_coeffs_odd[i];
    }
    xout1 = NLDECOMPRESS_PREPROCESS_SAMPLE_WITH_GAIN((int16_t)__ssat16(xout1 >> 11), gain);
    xout2 = NLDECOMPRESS_PREPROCESS_SAMPLE_WITH_GAIN((int16_t)__ssat16(xout2 >> 11), gain);
    if (s->dac_pcm) {
      amp[outlen++] = ((int16_t)(xout1 >> 4) + 2048);
      amp[outlen++] = ((int16_t)(xout2 >> 4) + 2048);
    } else {
      amp[outlen++] = xout1;
      amp[outlen++] = xout2;
    }
  }
  return outlen;
}
/*- End of function --------------------------------------------------------*/
/*- End of file ------------------------------------------------------------*/