/* 
 * Mpeg Layer-2 audio decoder 
 * --------------------------
 * copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README'
 *
 */

#include "mpg123.h"
#include "audacious/output.h"
#include "l2tables.h"
#include "getbits.h"

#include <math.h>

static int grp_3tab[32 * 3] = { 0, };	/* used: 27 */
static int grp_5tab[128 * 3] = { 0, };	/* used: 125 */
static int grp_9tab[1024 * 3] = { 0, };	/* used: 729 */

mpgdec_real mpgdec_muls[27][64];	/* also used by layer 1 */

void
mpgdec_init_layer2 (gboolean mmx)
{
  static double mulmul[27] = {
    0.0, -2.0 / 3.0, 2.0 / 3.0, 2.0 / 7.0, 2.0 / 15.0,
    2.0 / 31.0, 2.0 / 63.0, 2.0 / 127.0, 2.0 / 255.0,
    2.0 / 511.0, 2.0 / 1023.0, 2.0 / 2047.0, 2.0 / 4095.0,
    2.0 / 8191.0, 2.0 / 16383.0, 2.0 / 32767.0, 2.0 / 65535.0,
    -4.0 / 5.0, -2.0 / 5.0, 2.0 / 5.0, 4.0 / 5.0, -8.0 / 9.0,
    -4.0 / 9.0, -2.0 / 9.0, 2.0 / 9.0, 4.0 / 9.0, 8.0 / 9.0
  };
  static int base[3][9] = {
    {1, 0, 2,},
    {17, 18, 0, 19, 20,},
    {21, 1, 22, 23, 0, 24, 25, 2, 26}
  };
  int i, j, k, l, len;
  mpgdec_real *table;
  static int tablen[3] = { 3, 5, 9 };
  static int *itable, *tables[3] = { grp_3tab, grp_5tab, grp_9tab };

  for (i = 0; i < 3; i++)
    {
      itable = tables[i];
      len = tablen[i];
      for (j = 0; j < len; j++)
	for (k = 0; k < len; k++)
	  for (l = 0; l < len; l++)
	    {
	      *itable++ = base[i][l];
	      *itable++ = base[i][k];
	      *itable++ = base[i][j];
	    }
    }

  for (k = 0; k < 27; k++)
    {
      double m = mulmul[k];
      table = mpgdec_muls[k];
      for (j = 3, i = 0; i < 63; i++, j--)
        *table++ = m * pow (2.0, (double) j / 3.0);
      *table++ = 0.0;
    }
}

void
II_step_one (unsigned int *bit_alloc, int *scale, struct frame *fr)
{
  int stereo = fr->stereo - 1;
  int sblimit = fr->II_sblimit;
  int jsbound = fr->jsbound;
  int sblimit2 = fr->II_sblimit << stereo;
  struct al_table *alloc1 = fr->alloc;
  int i;
  static unsigned int scfsi_buf[64];
  unsigned int *scfsi, *bita;
  int sc, step;

  bita = bit_alloc;
  if (stereo)
    {
      for (i = jsbound; i > 0; i--, alloc1 += (1 << step))
	{
	  *bita++ = (char) mpgdec_getbits (&bsi, step = alloc1->bits);
	  *bita++ = (char) mpgdec_getbits (&bsi, step);
	}
      for (i = sblimit - jsbound; i > 0; i--, alloc1 += (1 << step))
	{
	  bita[0] = (char) mpgdec_getbits (&bsi, step = alloc1->bits);
	  bita[1] = bita[0];
	  bita += 2;
	}
      bita = bit_alloc;
      scfsi = scfsi_buf;
      for (i = sblimit2; i; i--)
	if (*bita++)
	  *scfsi++ = (char) mpgdec_getbits_fast (&bsi, 2);
    }
  else
    /* mono */
    {
      for (i = sblimit; i; i--, alloc1 += (1 << step))
	*bita++ = (char) mpgdec_getbits (&bsi, step = alloc1->bits);
      bita = bit_alloc;
      scfsi = scfsi_buf;
      for (i = sblimit; i; i--)
	if (*bita++)
	  *scfsi++ = (char) mpgdec_getbits_fast (&bsi, 2);
    }

  bita = bit_alloc;
  scfsi = scfsi_buf;
  for (i = sblimit2; i; i--)
    if (*bita++)
      switch (*scfsi++)
	{
	case 0:
	  *scale++ = mpgdec_getbits_fast (&bsi, 6);
	  *scale++ = mpgdec_getbits_fast (&bsi, 6);
	  *scale++ = mpgdec_getbits_fast (&bsi, 6);
	  break;
	case 1:
	  *scale++ = sc = mpgdec_getbits_fast (&bsi, 6);
	  *scale++ = sc;
	  *scale++ = mpgdec_getbits_fast (&bsi, 6);
	  break;
	case 2:
	  *scale++ = sc = mpgdec_getbits_fast (&bsi, 6);
	  *scale++ = sc;
	  *scale++ = sc;
	  break;
	default:		/* case 3 */
	  *scale++ = mpgdec_getbits_fast (&bsi, 6);
	  *scale++ = sc = mpgdec_getbits_fast (&bsi, 6);
	  *scale++ = sc;
	  break;
	}

}

void
II_step_two (unsigned int *bit_alloc, mpgdec_real fraction[2][4][SBLIMIT],
	     int *scale, struct frame *fr, int x1)
{
  int i, j, k, ba;
  int stereo = fr->stereo;
  int sblimit = fr->II_sblimit;
  int jsbound = fr->jsbound;
  struct al_table *alloc2, *alloc1 = fr->alloc;
  unsigned int *bita = bit_alloc;
  int d1, step;

  for (i = 0; i < jsbound; i++, alloc1 += (1 << step))
    {
      step = alloc1->bits;
      for (j = 0; j < stereo; j++)
	{
	  if ((ba = *bita++))
	    {
	      k = (alloc2 = alloc1 + ba)->bits;
	      if ((d1 = alloc2->d) < 0)
		{
		  mpgdec_real cm = mpgdec_muls[k][scale[x1]];

		  fraction[j][0][i] =
		    ((mpgdec_real) ((int) mpgdec_getbits (&bsi, k) + d1)) * cm;
		  fraction[j][1][i] =
		    ((mpgdec_real) ((int) mpgdec_getbits (&bsi, k) + d1)) * cm;
		  fraction[j][2][i] =
		    ((mpgdec_real) ((int) mpgdec_getbits (&bsi, k) + d1)) * cm;
		}
	      else
		{
		  static int *table[] =
		    { 0, 0, 0, grp_3tab, 0, grp_5tab, 0, 0, 0, grp_9tab };
		  unsigned int idx, *tab, m = scale[x1];

		  idx = (unsigned int) mpgdec_getbits (&bsi, k);
		  tab = (unsigned int *) (table[d1] + idx + idx + idx);
		  fraction[j][0][i] = mpgdec_muls[*tab++][m];
		  fraction[j][1][i] = mpgdec_muls[*tab++][m];
		  fraction[j][2][i] = mpgdec_muls[*tab][m];
		}
	      scale += 3;
	    }
	  else
	    fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
	}
    }

  for (i = jsbound; i < sblimit; i++, alloc1 += (1 << step))
    {
      step = alloc1->bits;
      bita++;			/* channel 1 and channel 2 bitalloc are the same */
      if ((ba = *bita++))
	{
	  k = (alloc2 = alloc1 + ba)->bits;
	  if ((d1 = alloc2->d) < 0)
	    {
	      mpgdec_real cm;

	      cm = mpgdec_muls[k][scale[x1 + 3]];
	      fraction[1][0][i] = (fraction[0][0][i] =
				   (mpgdec_real) ((int) mpgdec_getbits (&bsi, k) +
					   d1)) * cm;
	      fraction[1][1][i] = (fraction[0][1][i] =
				   (mpgdec_real) ((int) mpgdec_getbits (&bsi, k) +
					   d1)) * cm;
	      fraction[1][2][i] = (fraction[0][2][i] =
				   (mpgdec_real) ((int) mpgdec_getbits (&bsi, k) +
					   d1)) * cm;
	      cm = mpgdec_muls[k][scale[x1]];
	      fraction[0][0][i] *= cm;
	      fraction[0][1][i] *= cm;
	      fraction[0][2][i] *= cm;
	    }
	  else
	    {
	      static int *table[] =
		{ 0, 0, 0, grp_3tab, 0, grp_5tab, 0, 0, 0, grp_9tab };
	      unsigned int idx, *tab, m1, m2;

	      m1 = scale[x1];
	      m2 = scale[x1 + 3];
	      idx = (unsigned int) mpgdec_getbits (&bsi, k);
	      tab = (unsigned int *) (table[d1] + idx + idx + idx);
	      fraction[0][0][i] = mpgdec_muls[*tab][m1];
	      fraction[1][0][i] = mpgdec_muls[*tab++][m2];
	      fraction[0][1][i] = mpgdec_muls[*tab][m1];
	      fraction[1][1][i] = mpgdec_muls[*tab++][m2];
	      fraction[0][2][i] = mpgdec_muls[*tab][m1];
	      fraction[1][2][i] = mpgdec_muls[*tab][m2];
	    }
	  scale += 6;
	}
      else
	{
	  fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
	    fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
	}
/* 
   should we use individual scalefac for channel 2 or
   is the current way the right one , where we just copy channel 1 to
   channel 2 ?? 
   The current 'strange' thing is, that we throw away the scalefac
   values for the second channel ...!!
   -> changed .. now we use the scalefac values of channel one !! 
 */
    }

  if (sblimit > (fr->down_sample_sblimit))
    sblimit = fr->down_sample_sblimit;

  for (i = sblimit; i < SBLIMIT; i++)
    for (j = 0; j < stereo; j++)
      fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;

}

static void
II_select_table (struct frame *fr)
{
  static int translate[3][2][16] = {
    {{0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 1, 1, 1, 1, 1, 0},
     {0, 2, 2, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0}},
    {{0, 2, 2, 2, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0},
     {0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
    {{0, 3, 3, 3, 3, 3, 3, 0, 0, 0, 1, 1, 1, 1, 1, 0},
     {0, 3, 3, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0}}
  };

  int table, sblim;
  static struct al_table *tables[5] =
    { alloc_0, alloc_1, alloc_2, alloc_3, alloc_4 };
  static int sblims[5] = { 27, 30, 8, 12, 30 };

  if (fr->lsf)
    table = 4;
  else
    table =
      translate[fr->sampling_frequency][2 - fr->stereo][fr->bitrate_index];
  sblim = sblims[table];

  fr->alloc = tables[table];
  fr->II_sblimit = sblim;
}


int
mpgdec_do_layer2 (struct frame *fr)
{
  int i, j;
  int stereo = fr->stereo;
  mpgdec_real fraction[2][4][SBLIMIT];	/* pick_table clears unused subbands */
  unsigned int bit_alloc[64];
  int scale[192];
  int single = fr->single;

  II_select_table (fr);
  fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?
    (fr->mode_ext << 2) + 4 : fr->II_sblimit;
  if (fr->jsbound > fr->II_sblimit)
    fr->jsbound = fr->II_sblimit;

  if (stereo == 1 || single == 3)
    single = 0;

  II_step_one (bit_alloc, scale, fr);

  for (i = 0; i < SCALE_BLOCK; i++)
    {
      II_step_two (bit_alloc, fraction, scale, fr, i >> 2);
      for (j = 0; j < 3; j++)
	{
	  if (single >= 0)
	    {
	      (fr->synth_mono) (fraction[single][j], mpgdec_pcm_sample,
				&mpgdec_pcm_point);
	    }
	  else
	    {
	      int p1 = mpgdec_pcm_point;

	      (fr->synth) (fraction[0][j], 0, mpgdec_pcm_sample, &p1);
	      (fr->synth) (fraction[1][j], 1, mpgdec_pcm_sample,
			   &mpgdec_pcm_point);
	    }

	  /*    if(mpgdec_pcm_point >= audiobufsize)
	     audio_flush(outmode,ai); */
	}
    }
#ifdef PSYCHO
   psycho_process(mpgdec_pcm_sample, mpgdec_pcm_point, mpgdec_cfg.channels == 2 ? fr->stereo : 1);
#endif
  if (mpgdec_info->output_audio)
    {
      produce_audio (mpgdec_ip.output->written_time (),
		     mpgdec_cfg.resolution == 16 ? FMT_S16_NE : FMT_U8,
		     mpgdec_cfg.channels == 2 ? fr->stereo : 1,
		     mpgdec_pcm_point, mpgdec_pcm_sample, &mpgdec_pcm_point);
    }
  mpgdec_pcm_point = 0;

  return 1;
}
