/*
 *  mpadec - MPEG audio decoder
 *  Copyright (C) 2002-2004 Dmitriy Startsev (dstartsev@rambler.ru)
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* $Id: layer3.c,v 1.2 2004/12/13 06:47:35 metal_man Exp $ */

#include "mpadec_internal.h"

extern const uint32_t bitmask[17];
extern bandinfo_t band_info[];
extern newhuff_t hufft[], hufftc[];
extern const FLOAT newcos[8];
extern const FLOAT tfcos36[9];
extern const FLOAT tfcos12[3];
extern const FLOAT cs[8];
extern const FLOAT ca[8];

extern uint32_t getbits(mpadec_t mpadec, unsigned n);
extern uint16_t update_crc(uint16_t init, uint8_t *buf, int length);

static int decode_layer3_sideinfo(mpadec_t mpadec)
{
  register struct mpadec_t *mpa = (struct mpadec_t *)mpadec;
  int ch, gr, ms_stereo, powdiff, databits = 0;
  static const uint8_t tabs[2][5] = { { 2, 9, 5, 3, 4 }, { 1, 8, 1, 2, 9 } };
  const uint8_t *tab = tabs[mpa->frame.LSF];

  ms_stereo = ((mpa->frame.mode == MPG_MD_JOINT_STEREO) && (mpa->frame.mode_ext & 2));
  powdiff = ((mpa->frame.channels > 1) && (mpa->config.mode == MPADEC_CONFIG_MONO)) ? 4 : 0;
  mpa->sideinfo.main_data_begin = GETBITS(tab[1]);
  if (mpa->frame.channels == 1) mpa->sideinfo.private_bits = GETBITS(tab[2]);
  else mpa->sideinfo.private_bits = GETBITS(tab[3]);
  if (!mpa->frame.LSF) {
    for (ch = 0; ch < mpa->frame.channels; ch++) {
      mpa->sideinfo.ch[ch].gr[0].scfsi = -1;
      mpa->sideinfo.ch[ch].gr[1].scfsi = GETBITS(4);
    }
  }
  for (gr = 0; gr < tab[0]; gr++) {
    for (ch = 0; ch < mpa->frame.channels; ch++) {
      register grinfo_t *grinfo = &mpa->sideinfo.ch[ch].gr[gr];
      grinfo->part2_3_length = GETBITS(12);
      grinfo->big_values = GETBITS(9);
      databits += grinfo->part2_3_length;
      if (grinfo->big_values > 288) grinfo->big_values = 288;
      grinfo->pow2gain = mpa->tables.gainpow2 + 256 - GETBITS(8) + powdiff;
      if (ms_stereo) grinfo->pow2gain += 2;
      grinfo->scalefac_compress = GETBITS(tab[4]);
      if (GETBITS(1)) {
        grinfo->block_type = (uint8_t)GETBITS(2);
        grinfo->mixed_block_flag = (uint8_t)GETBITS(1);
        grinfo->table_select[0] = GETBITS(5);
        grinfo->table_select[1] = GETBITS(5);
        grinfo->table_select[2] = 0;
        grinfo->full_gain[0] = grinfo->pow2gain + (GETBITS(3) << 3);
        grinfo->full_gain[1] = grinfo->pow2gain + (GETBITS(3) << 3);
        grinfo->full_gain[2] = grinfo->pow2gain + (GETBITS(3) << 3);
        if (!grinfo->block_type) {
          mpa->error = TRUE;
          return 0;
        } else mpa->error = FALSE;
        if (mpa->frame.LSF) {
          if (grinfo->block_type == 2) {
            if (grinfo->mixed_block_flag) {
              if (mpa->frame.frequency_index == 8) grinfo->region1start = 48;
              else grinfo->region1start = 48 >> 1;
            } else {
              if (mpa->frame.frequency_index == 8) grinfo->region1start = 36;
              else grinfo->region1start = 36 >> 1;
            }
          } else {
            if (mpa->frame.frequency_index == 8) grinfo->region1start = 54;
            else grinfo->region1start = 54 >> 1;
          }
        } else grinfo->region1start = 36 >> 1;
        grinfo->region2start = 576 >> 1;
      } else {
        grinfo->block_type = 0;
        grinfo->mixed_block_flag = 0;
        grinfo->table_select[0] = GETBITS(5);
        grinfo->table_select[1] = GETBITS(5);
        grinfo->table_select[2] = GETBITS(5);
        {
          register int tmp = GETBITS(4);
          grinfo->region1start = band_info[mpa->frame.frequency_index].long_idx[tmp + 1] >> 1;
          tmp += GETBITS(3);
          grinfo->region2start = band_info[mpa->frame.frequency_index].long_idx[tmp + 2] >> 1;
        }
      }
      if (!mpa->frame.LSF) grinfo->preflag = (uint8_t)GETBITS(1);
      grinfo->scalefac_scale = (uint8_t)GETBITS(1);
      grinfo->count1table_select = (uint8_t)GETBITS(1);
    }
  }
  databits -= 8*mpa->sideinfo.main_data_begin;
  return databits;
}

static int III_get_scale_factors(mpadec_t mpadec, grinfo_t *gr_info, int32_t *scf)
{
  register struct mpadec_t *mpa = (struct mpadec_t *)mpadec;
  register grinfo_t *grinfo = gr_info;
  int numbits = 0;
  static uint8_t slen[2][16] = { {0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4},
                                 {0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3} };
  static uint8_t stab[3][6][4] = { { { 6, 5, 5,5 } , { 6, 5, 7,3 } , { 11,10,0,0} ,
                                     { 7, 7, 7,0 } , { 6, 6, 6,3 } , {  8, 8,5,0} } ,
                                   { { 9, 9, 9,9 } , { 9, 9,12,6 } , { 18,18,0,0} ,
                                     {12,12,12,0 } , {12, 9, 9,6 } , { 15,12,9,0} } ,
                                   { { 6, 9, 9,9 } , { 6, 9,12,6 } , { 15,18,0,0} ,
                                     { 6,15,12,0 } , { 6,12, 9,6 } , {  6,18,9,0} } };

  if (!mpa->frame.LSF) {
    int i, num0 = slen[0][grinfo->scalefac_compress], num1 = slen[1][grinfo->scalefac_compress];
    if (grinfo->block_type == 2) {
      i = 18; numbits = 18*(num0 + num1);
      if (grinfo->mixed_block_flag) {
        i--;
        numbits -= num0;
      }
      for (; i; i--) *scf++ = GETBITS(num0);
      for (i = 18; i; i--) *scf++ = GETBITS(num1);
      scf[0] = scf[1] = scf[2] = 0;
    } else {
      if (grinfo->scfsi < 0) {
        for (i = 11; i; i--) *scf++ = GETBITS(num0);
        for (i = 10; i; i--) *scf++ = GETBITS(num1);
        numbits = 10*(num0 + num1) + num0;
        *scf = 0;
      } else {
        numbits = 0;
        if (!(grinfo->scfsi & 8)) {
          for (i = 6; i; i--) *scf++ = GETBITS(num0);
          numbits += 6*num0;
        } else scf += 6;
        if (!(grinfo->scfsi & 4)) {
          for (i = 5; i; i--) *scf++ = GETBITS(num0);
          numbits += 5*num0;
        } else scf += 5;
        if (!(grinfo->scfsi & 2)) {
          for (i = 5; i; i--) *scf++ = GETBITS(num1);
          numbits += 5*num1;
        } else scf += 5;
        if (!(grinfo->scfsi & 1)) {
          for (i = 5; i; i--) *scf++ = GETBITS(num1);
          numbits += 5*num1;
        } else scf += 5;
        *scf = 0;
      }
    }
  } else {
    int i, j, n = 0;
    unsigned s_len; uint8_t *pnt;
    if ((mpa->frame.mode == MPG_MD_JOINT_STEREO) && (mpa->frame.mode_ext & 1)) {
      s_len = mpa->tables.i_slen2[grinfo->scalefac_compress >> 1];
    } else s_len = mpa->tables.n_slen2[grinfo->scalefac_compress];
    grinfo->preflag = (uint8_t)((s_len >> 15) & 1);
    if (grinfo->block_type == 2) n = grinfo->mixed_block_flag ? 2 : 1;
    pnt = stab[n][(s_len >> 12) & 7];
    for (i = 0; i < 4; i++) {
      int num = s_len & 7;
      s_len >>= 3;
      if (num) {
        for (j = 0; j < (int)pnt[i]; j++) *scf++ = GETBITS(num);
        numbits += pnt[i]*num;
      } else for (j = 0; j < (int)pnt[i]; j++) *scf++ = 0;
    }
    for (i = (n << 1) + 1; i; i--) *scf++ = 0;
  }
  return numbits;
}

static int III_decode_samples(mpadec_t mpadec, grinfo_t *gr_info, FLOAT xr[SBLIMIT][SSLIMIT], int32_t *scf, int part2bits)
{
  register struct mpadec_t *mpa = (struct mpadec_t *)mpadec;
  register grinfo_t *grinfo = gr_info;
  int shift = 1 + grinfo->scalefac_scale, l[3], l3;
  int part2remain = grinfo->part2_3_length - part2bits;
  FLOAT *xrptr = (FLOAT *)xr; int32_t *me;
  static uint8_t pretab1[22] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0 };
  static uint8_t pretab2[22] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

  l3 = ((576 >> 1) - grinfo->big_values) >> 1;
  if (grinfo->big_values <= grinfo->region1start) {
    l[0] = grinfo->big_values;
    l[1] = l[2] = 0;
  } else {
    l[0] = grinfo->region1start;
    if (grinfo->big_values <= grinfo->region2start) {
      l[1] = grinfo->big_values - l[0]; l[2] = 0;
    } else {
      l[1] = grinfo->region2start - l[0];
      l[2] = grinfo->big_values - grinfo->region2start;
    }
  }
  if (grinfo->block_type == 2) {
    int32_t i, max[4], step = 0, lwin = 0, cb = 0;
    register FLOAT v = 0.0;
    register int32_t *m, mc;

    if (grinfo->mixed_block_flag) {
      max[3] = -1;
      max[0] = max[1] = max[2] = 2;
      m = mpa->tables.map[mpa->frame.frequency_index][0];
      me = mpa->tables.mapend[mpa->frame.frequency_index][0];
    } else {
      max[0] = max[1] = max[2] = max[3] = -1;
      m = mpa->tables.map[mpa->frame.frequency_index][1];
      me = mpa->tables.mapend[mpa->frame.frequency_index][1];
    }
    mc = 0;
    for (i = 0; i < 2; i++) {
      int lp = l[i];
      newhuff_t *h = hufft + grinfo->table_select[i];
      for (; lp; lp--, mc--) {
        register int x, y;
        if (!mc) {
          mc = *m++;
          xrptr = ((FLOAT *)xr) + (*m++);
          lwin = *m++;
          cb = *m++;
          if (lwin == 3) {
            v = grinfo->pow2gain[(*scf++) << shift];
            step = 1;
          } else {
            v = grinfo->full_gain[lwin][(*scf++) << shift];
            step = 3;
          }
        }
        {
          register int16_t *val = h->table;
          while ((y = *val++) < 0) {
            if (GETBITS(1)) val -= y;
            part2remain--;
          }
          x = y >> 4;
          y &= 0x0F;
        }
        if ((x == 15) && h->linbits) {
          max[lwin] = cb;
          part2remain -= h->linbits + 1;
          x += GETBITS(h->linbits);
          if (GETBITS(1)) *xrptr = -mpa->tables.ispow[x]*v;
          else *xrptr = mpa->tables.ispow[x]*v;
        } else if (x) {
          max[lwin] = cb;
          if (GETBITS(1)) *xrptr = -mpa->tables.ispow[x]*v;
          else *xrptr = mpa->tables.ispow[x]*v;
          part2remain--;
        } else *xrptr = 0.0;
        xrptr += step;
        if ((y == 15) && h->linbits) {
          max[lwin] = cb;
          part2remain -= h->linbits + 1;
          y += GETBITS(h->linbits);
          if (GETBITS(1)) *xrptr = -mpa->tables.ispow[y]*v;
          else *xrptr = mpa->tables.ispow[y]*v;
        } else if (y) {
          max[lwin] = cb;
          if (GETBITS(1)) *xrptr = -mpa->tables.ispow[y]*v;
          else *xrptr = mpa->tables.ispow[y]*v;
          part2remain--;
        } else *xrptr = 0.0;
        xrptr += step;
      }
    }
    for (; l3 && (part2remain > 0); l3--) {
      newhuff_t *h = hufftc + grinfo->count1table_select;
      register int16_t *val = h->table, a;
      while ((a = *val++) < 0) {
        part2remain--;
        if (part2remain < 0) {
          part2remain++;
          a = 0;
          break;
        }
        if (GETBITS(1)) val -= a;
      }
      for (i = 0; i < 4; i++) {
        if (!(i & 1)) {
          if (!mc) {
            mc = *m++;
            xrptr = ((FLOAT *)xr) + (*m++);
            lwin = *m++;
            cb = *m++;
            if (lwin == 3) {
              v = grinfo->pow2gain[(*scf++) << shift];
              step = 1;
            } else {
              v = grinfo->full_gain[lwin][(*scf++) << shift];
              step = 3;
            }
          }
          mc--;
        }
        if (a & (8 >> i)) {
          max[lwin] = cb;
          part2remain--;
          if (part2remain < 0) {
            part2remain++;
            break;
          }
          if (GETBITS(1)) *xrptr = -v;
          else *xrptr = v;
        } else *xrptr = 0.0;
        xrptr += step;
      }
    }
    if (lwin < 3) {
      while (1) {
        for (; mc > 0; mc--) {
          xrptr[0] = xrptr[3] = 0.0;
          xrptr += 6;
        }
        if (m >= me) break;
        mc = *m++;
        xrptr = ((FLOAT *)xr) + (*m++);
        if ((*m++) == 0) break;
        m++;
      }
    }
    grinfo->maxband[0] = max[0] + 1;
    grinfo->maxband[1] = max[1] + 1;
    grinfo->maxband[2] = max[2] + 1;
    grinfo->maxbandl = max[3] + 1;
    {
      int rmax = max[0] > max[1] ? max[0] : max[1];
      rmax = (rmax > max[2] ? rmax : max[2]) + 1;
      grinfo->maxb = rmax ? mpa->tables.short_limit[mpa->frame.frequency_index][rmax] : mpa->tables.long_limit[mpa->frame.frequency_index][max[3] + 1];
    }
  } else {
    uint8_t *pretab = grinfo->preflag ? pretab1 : pretab2;
    int32_t i, max = -1, cb = 0, mc = 0;
    int32_t *m = mpa->tables.map[mpa->frame.frequency_index][2];
    register FLOAT v = 0.0;

    for (i = 0; i < 3; i++) {
      int lp = l[i];
      newhuff_t *h = hufft + grinfo->table_select[i];
      for (; lp; lp--, mc--) {
        register int x, y;
        if (!mc) {
          mc = *m++;
          cb = *m++;
          if (cb == 21) v = 0.0;
          else v = grinfo->pow2gain[((*scf++) + (*pretab++)) << shift];
        }
        {
          register int16_t *val = h->table;
          while ((y = *val++) < 0) {
            if (GETBITS(1)) val -= y;
            part2remain--;
          }
          x = y >> 4;
          y &= 0x0F;
        }
        if ((x == 15) && h->linbits) {
          max = cb;
          part2remain -= h->linbits + 1;
          x += GETBITS(h->linbits);
          if (GETBITS(1)) *xrptr++ = -mpa->tables.ispow[x]*v;
          else *xrptr++ = mpa->tables.ispow[x]*v;
        } else if (x) {
          max = cb;
          if (GETBITS(1)) *xrptr++ = -mpa->tables.ispow[x]*v;
          else *xrptr++ = mpa->tables.ispow[x]*v;
          part2remain--;
        } else *xrptr++ = 0.0;
        if ((y == 15) && h->linbits) {
          max = cb;
          part2remain -= h->linbits + 1;
          y += GETBITS(h->linbits);
          if (GETBITS(1)) *xrptr++ = -mpa->tables.ispow[y]*v;
          else *xrptr++ = mpa->tables.ispow[y]*v;
        } else if (y) {
          max = cb;
          if (GETBITS(1)) *xrptr++ = -mpa->tables.ispow[y]*v;
          else *xrptr++ = mpa->tables.ispow[y]*v;
          part2remain--;
        } else *xrptr++ = 0.0;
      }
    }
    for (; l3 && (part2remain > 0); l3--) {
      newhuff_t *h = hufftc + grinfo->count1table_select;
      register int16_t *val = h->table, a;
      while ((a = *val++) < 0) {
        part2remain--;
        if (part2remain < 0) {
          part2remain++;
          a = 0;
          break;
        }
        if (GETBITS(1)) val -= a;
      }
      for (i = 0; i < 4; i++) {
        if (!(i & 1)) {
          if (!mc) {
            mc = *m++;
            cb = *m++;
            v = grinfo->pow2gain[((*scf++) + (*pretab++)) << shift];
          }
          mc--;
        }
        if (a & (8 >> i)) {
          max = cb;
          part2remain--;
          if (part2remain < 0) {
            part2remain++;
            break;
          }
          if (GETBITS(1)) *xrptr++ = -v;
          else *xrptr++ = v;
        } else *xrptr++ = 0.0;
      }
    }
    grinfo->maxbandl = max + 1;
    grinfo->maxb = mpa->tables.long_limit[mpa->frame.frequency_index][max + 1];
  }
  while (xrptr < &xr[SBLIMIT][0]) *xrptr++ = 0.0;
  while (part2remain > 0) {
    register unsigned tmp, i = (part2remain > 16) ? 16 : part2remain;
    tmp = GETBITS(i);
    part2remain -= i;
    i = tmp;
  }
  mpa->error = (uint8_t)((part2remain < 0) ? TRUE : FALSE);
  return mpa->error;
}

static void III_i_stereo(mpadec_t mpadec, grinfo_t *gr_info, FLOAT xrbuf[2][SBLIMIT][SSLIMIT], int32_t *scalefac)
{
  register struct mpadec_t *mpa = (struct mpadec_t *)mpadec;
  register grinfo_t *grinfo = gr_info;
  FLOAT (*xr)[SBLIMIT*SSLIMIT] = (FLOAT (*)[SBLIMIT*SSLIMIT])xrbuf;
  bandinfo_t *bi = &band_info[mpa->frame.frequency_index];
  int tab = mpa->frame.LSF + (grinfo->scalefac_compress & mpa->frame.LSF);
  int ms_stereo = ((mpa->frame.mode == MPG_MD_JOINT_STEREO) && (mpa->frame.mode_ext & 2)) ? TRUE : FALSE;
  const FLOAT *tab1, *tab2;

  tab1 = mpa->tables.istabs[tab][ms_stereo][0];
  tab2 = mpa->tables.istabs[tab][ms_stereo][1];
  if (grinfo->block_type == 2) {
    int lwin, do_l = grinfo->mixed_block_flag;
    for (lwin = 0; lwin < 3; lwin++) {
      int32_t is_p, sb, idx, sfb = grinfo->maxband[lwin];
      if (sfb > 3) do_l = FALSE;
      for (; sfb < 12; sfb++) {
        is_p = scalefac[3*sfb + lwin - grinfo->mixed_block_flag];
        if (is_p != 7) {
          FLOAT t1 = tab1[is_p], t2 = tab2[is_p];
          sb = bi->short_diff[sfb];
          idx = bi->short_idx[sfb] + lwin;
          for (; sb; sb--, idx += 3) {
            register FLOAT v = xr[0][idx];
            xr[0][idx] = v*t1;
            xr[1][idx] = v*t2;
          }
        }
      }
      is_p = scalefac[3*11 + lwin - grinfo->mixed_block_flag];
      sb = bi->short_diff[12];
      idx = bi->short_idx[12] + lwin;
      if (is_p != 7) {
        FLOAT t1 = tab1[is_p], t2 = tab2[is_p];
        for (; sb; sb--, idx += 3) {
          register FLOAT v = xr[0][idx];
          xr[0][idx] = v*t1;
          xr[1][idx] = v*t2;
        }
      }
    }
    if (do_l) {
      int sfb = grinfo->maxbandl;
      int idx = bi->long_idx[sfb];
      for (; sfb < 8; sfb++) {
        int sb = bi->long_diff[sfb];
        int is_p = scalefac[sfb];
        if (is_p != 7) {
          FLOAT t1 = tab1[is_p], t2 = tab2[is_p];
          for (; sb; sb--, idx++) {
            register FLOAT v = xr[0][idx];
            xr[0][idx] = v*t1;
            xr[1][idx] = v*t2;
          }
        } else idx += sb;
      }
    }
  } else {
    int sfb = grinfo->maxbandl;
    int is_p, idx = bi->long_idx[sfb];
    for (; sfb < 21; sfb++) {
      int sb = bi->long_diff[sfb];
      is_p = scalefac[sfb];
      if (is_p != 7) {
        FLOAT t1 = tab1[is_p], t2 = tab2[is_p];
        for (; sb; sb--, idx++) {
          register FLOAT v = xr[0][idx];
          xr[0][idx] = v*t1;
          xr[1][idx] = v*t2;
        }
      } else idx += sb;
    }
    is_p = scalefac[20];
    if (is_p != 7) {
      int sb = bi->long_diff[21];
      FLOAT t1 = tab1[is_p], t2 = tab2[is_p];
      for (; sb; sb--, idx++) {
        register FLOAT v = xr[0][idx];
        xr[0][idx] = v*t1;
        xr[1][idx] = v*t2;
      }
    }
  }
}

static void III_antialias(grinfo_t *gr_info, FLOAT xr[SBLIMIT][SSLIMIT])
{
  register grinfo_t *grinfo = gr_info;
  int sblim;

  if (grinfo->block_type == 2) {
    if (!grinfo->mixed_block_flag) return;
    sblim = 1;
  } else sblim = grinfo->maxb - 1;
  {
    int sb;
    FLOAT *xr1 = (FLOAT *)xr[1];
    for (sb = sblim; sb; sb--, xr1 += 10) {
      int ss;
      FLOAT *xr2 = xr1;
      for (ss = 0; ss < 8; ss++) {
        register FLOAT bu = *--xr2, bd = *xr1;
        *xr2 = bu*cs[ss] - bd*ca[ss];
        *xr1++ = bd*cs[ss] + bu*ca[ss];
      }
    }
  }
}

static void dct36(register FLOAT *in, register FLOAT *out1, register FLOAT *out2, register FLOAT *w, register FLOAT *ts)
{
  FLOAT tmp[18];

  {
    in[17] += in[16]; in[16] += in[15]; in[15] += in[14];
    in[14] += in[13]; in[13] += in[12]; in[12] += in[11];
    in[11] += in[10]; in[10] += in[9];  in[9]  += in[8];
    in[8]  += in[7];  in[7]  += in[6];  in[6]  += in[5];
    in[5]  += in[4];  in[4]  += in[3];  in[3]  += in[2];
    in[2]  += in[1];  in[1]  += in[0];

    in[17] += in[15]; in[15] += in[13]; in[13] += in[11]; in[11] += in[9];
    in[9]  += in[7];  in[7]  += in[5];  in[5]  += in[3];  in[3]  += in[1];

    {
      FLOAT t3;
      {
        FLOAT t0, t1, t2;

        t0 = newcos[7]*(in[8] + in[16] - in[4]);
        t1 = newcos[7]*in[12];
        t3 = in[0];
        t2 = t3 - t1 - t1;
        tmp[1] = tmp[7] = t2 - t0;
        tmp[4] = t2 + t0 + t0;
        t3 += t1;
        t2 = newcos[6]*(in[10] + in[14] - in[2]);
        tmp[1] -= t2;
        tmp[7] += t2;
      }
      {
        FLOAT t0, t1, t2;

        t0 = newcos[0]*(in[4] + in[8]);
        t1 = newcos[1]*(in[8] - in[16]);
        t2 = newcos[2]*(in[4] + in[16]);
        tmp[2] = tmp[6] = t3 - t0 - t2;
        tmp[0] = tmp[8] = t3 + t0 + t1;
        tmp[3] = tmp[5] = t3 - t1 + t2;
      }
    }
    {
      FLOAT t1, t2, t3;

      t1 = newcos[3]*(in[2] + in[10]);
      t2 = newcos[4]*(in[10] - in[14]);
      t3 = newcos[6]*in[6];
      {
        FLOAT t0 = t1 + t2 + t3;
        tmp[0] += t0;
        tmp[8] -= t0;
      }
      t2 -= t3;
      t1 -= t3;
      t3 = newcos[5]*(in[2] + in[14]);
      t1 += t3;
      tmp[3] += t1;
      tmp[5] -= t1;
      t2 -= t3;
      tmp[2] += t2;
      tmp[6] -= t2;
    }
    {
      FLOAT t0, t1, t2, t3, t4, t5, t6, t7;

      t1 = newcos[7]*in[13];
      t2 = newcos[7]*(in[9] + in[17] - in[5]);
      t3 = in[1] + t1;
      t4 = in[1] - t1 - t1;
      t5 = t4 - t2;
      t0 = newcos[0]*(in[5] + in[9]);
      t1 = newcos[1]*(in[9] - in[17]);
      tmp[13] = (t4 + t2 + t2)*tfcos36[17 - 13];
      t2 = newcos[2]*(in[5] + in[17]);
      t6 = t3 - t0 - t2;
      t0 += t3 + t1;
      t3 += t2 - t1;
      t2 = newcos[3]*(in[3] + in[11]);
      t4 = newcos[4]*(in[11] - in[15]);
      t7 = newcos[6]*in[7];
      t1 = t2 + t4 + t7;
      tmp[17] = (t0 + t1)*tfcos36[17 - 17];
      tmp[9] = (t0 - t1)*tfcos36[17 - 9];
      t1 = newcos[5]*(in[3] + in[15]);
      t2 += t1 - t7;
      tmp[14] = (t3 + t2)*tfcos36[17 - 14];
      t0 = newcos[6]*(in[11] + in[15] - in[3]);
      tmp[12] = (t3 - t2)*tfcos36[17 - 12];
      t4 -= t1 + t7;
      tmp[16] = (t5 - t0)*tfcos36[17 - 16];
      tmp[10] = (t5 + t0)*tfcos36[17 - 10];
      tmp[15] = (t6 + t4)*tfcos36[17 - 15];
      tmp[11] = (t6 - t4)*tfcos36[17 - 11];
    }
  }
#define DCT36_MACRO(v) { \
    register FLOAT tmpval = tmp[(v)] + tmp[17 - (v)]; \
    out2[9 + (v)] = tmpval*w[27 + (v)]; \
    out2[8 - (v)] = tmpval*w[26 - (v)]; \
    tmpval = tmp[(v)] - tmp[17 - (v)]; \
    ts[SBLIMIT*(8 - (v))] = out1[8 - (v)] + tmpval*w[8 - (v)]; \
    ts[SBLIMIT*(9 + (v))] = out1[9 + (v)] + tmpval*w[9 + (v)]; \
  }
  {
    DCT36_MACRO(0);
    DCT36_MACRO(1);
    DCT36_MACRO(2);
    DCT36_MACRO(3);
    DCT36_MACRO(4);
    DCT36_MACRO(5);
    DCT36_MACRO(6);
    DCT36_MACRO(7);
    DCT36_MACRO(8);
  }
#undef DCT36_MACRO
}

static void dct12(register FLOAT *in, register FLOAT *out1, register FLOAT *out2, register FLOAT *w, register FLOAT *ts)
{
#define DCT12_PART1 in5 = in[5*3]; \
                    in5 += (in4 = in[4*3]); \
                    in4 += (in3 = in[3*3]); \
                    in3 += (in2 = in[2*3]); \
                    in2 += (in1 = in[1*3]); \
                    in1 += (in0 = in[0*3]); \
                    in5 += in3; in3 += in1; \
                    in2 *= newcos[6]; \
                    in3 *= newcos[6];

#define DCT12_PART2 in0 += in4*newcos[7]; \
                    in4 = in0 + in2; \
                    in0 -= in2; \
                    in1 += in5*newcos[7]; \
                    in5 = (in1 + in3)*tfcos12[0]; \
                    in1 = (in1 - in3)*tfcos12[2]; \
                    in3 = in4 + in5; \
                    in4 -= in5; \
                    in2 = in0 + in1; \
                    in0 -= in1;

  {
    FLOAT in0, in1, in2, in3, in4, in5;

    ts[0*SBLIMIT] = out1[0]; ts[1*SBLIMIT] = out1[1]; ts[2*SBLIMIT] = out1[2];
    ts[3*SBLIMIT] = out1[3]; ts[4*SBLIMIT] = out1[4]; ts[5*SBLIMIT] = out1[5];

    DCT12_PART1

    {
      register FLOAT tmp0, tmp1 = in0 - in4;
      {
        register FLOAT tmp2 = (in1 - in5)*tfcos12[1];
        tmp0 = tmp1 + tmp2;
        tmp1 -= tmp2;
      }
      ts[(17 - 1)*SBLIMIT] = out1[17 - 1] + tmp0*w[11 - 1];
      ts[(12 + 1)*SBLIMIT] = out1[12 + 1] + tmp0*w[6 + 1];
      ts[(6 + 1)*SBLIMIT] = out1[6 + 1] + tmp1*w[1];
      ts[(11 - 1)*SBLIMIT] = out1[11 - 1] + tmp1*w[5 - 1];
    }

    DCT12_PART2

    ts[(17 - 0)*SBLIMIT] = out1[17 - 0] + in2*w[11 - 0];
    ts[(12 + 0)*SBLIMIT] = out1[12 + 0] + in2*w[6 + 0];
    ts[(12 + 2)*SBLIMIT] = out1[12 + 2] + in3*w[6 + 2];
    ts[(17 - 2)*SBLIMIT] = out1[17 - 2] + in3*w[11 - 2];
    ts[(6 + 0)*SBLIMIT]  = out1[6 + 0] + in0*w[0];
    ts[(11 - 0)*SBLIMIT] = out1[11 - 0] + in0*w[5 - 0];
    ts[(6 + 2)*SBLIMIT]  = out1[6 + 2] + in4*w[2];
    ts[(11 - 2)*SBLIMIT] = out1[11 - 2] + in4*w[5 - 2];
  }
  in++;
  {
    FLOAT in0, in1, in2, in3, in4, in5;

    DCT12_PART1

    {
      register FLOAT tmp0, tmp1 = in0 - in4;
      {
        register FLOAT tmp2 = (in1 - in5)*tfcos12[1];
        tmp0 = tmp1 + tmp2;
        tmp1 -= tmp2;
      }
      out2[5 - 1] = tmp0*w[11 - 1];
      out2[0 + 1] = tmp0*w[6 + 1];
      ts[(12 + 1)*SBLIMIT] += tmp1*w[0 + 1];
      ts[(17 - 1)*SBLIMIT] += tmp1*w[5 - 1];
    }

    DCT12_PART2

    out2[5 - 0] = in2*w[11 - 0];
    out2[0 + 0] = in2*w[6 + 0];
    out2[0 + 2] = in3*w[6 + 2];
    out2[5 - 2] = in3*w[11 - 2];
    ts[(12 + 0)*SBLIMIT] += in0*w[0];
    ts[(17 - 0)*SBLIMIT] += in0*w[5 - 0];
    ts[(12 + 2)*SBLIMIT] += in4*w[2];
    ts[(17 - 2)*SBLIMIT] += in4*w[5 - 2];
  }
  in++;
  {
    FLOAT in0, in1, in2, in3, in4, in5;

    out2[12] = out2[13] = out2[14] = out2[15] = out2[16] = out2[17] = 0.0;

    DCT12_PART1

    {
      register FLOAT tmp0, tmp1 = in0 - in4;
      {
        register FLOAT tmp2 = (in1 - in5)*tfcos12[1];
        tmp0 = tmp1 + tmp2;
        tmp1 -= tmp2;
      }
      out2[11 - 1] = tmp0*w[11 - 1];
      out2[6 + 1] = tmp0*w[6 + 1];
      out2[0 + 1] += tmp1*w[1];
      out2[5 - 1] += tmp1*w[5 - 1];
    }

    DCT12_PART2

    out2[11 - 0] = in2*w[11 - 0];
    out2[6 + 0] = in2*w[6 + 0];
    out2[6 + 2] = in3*w[6 + 2];
    out2[11 - 2] = in3*w[11 - 2];
    out2[0 + 0] += in0*w[0];
    out2[5 - 0] += in0*w[5 - 0];
    out2[0 + 2] += in4*w[2];
    out2[5 - 2] += in4*w[5 - 2];
  }
#undef DCT12_PART1
#undef DCT12_PART2
}

static void III_hybrid(mpadec_t mpadec, grinfo_t *gr_info, FLOAT fs_in[SBLIMIT][SSLIMIT], FLOAT ts_out[SSLIMIT][SBLIMIT], int channel)
{
  register struct mpadec_t *mpa = (struct mpadec_t *)mpadec;
  register grinfo_t *grinfo = gr_info;
  FLOAT *tsptr = (FLOAT *)ts_out;
  FLOAT *out1, *out2;
  unsigned bt = grinfo->block_type, sb = 0;

  {
    register unsigned b = mpa->hybrid_block[channel];
    out1 = mpa->hybrid_buffers[b][channel];
    b ^= 1;
    out2 = mpa->hybrid_buffers[b][channel];
    mpa->hybrid_block[channel] = (uint8_t)b;
  }
  if (grinfo->mixed_block_flag) {
    sb = 2;
    dct36(fs_in[0], out1, out2, mpa->tables.win[0][0], tsptr);
    dct36(fs_in[1], out1 + SSLIMIT, out2 + SSLIMIT, mpa->tables.win[1][0], tsptr + 1);
    out1 += 36; out2 += 36; tsptr += 2;
  }
  if (bt == 2) {
    for (; sb < grinfo->maxb; sb += 2, out1 += 36, out2 += 36, tsptr += 2) {
      dct12(fs_in[sb], out1, out2, mpa->tables.win[0][2], tsptr);
      dct12(fs_in[sb + 1], out1 + SSLIMIT, out2 + SSLIMIT, mpa->tables.win[1][2], tsptr + 1);
    }
  } else {
    for (; sb < grinfo->maxb; sb += 2, out1 += 36, out2 += 36, tsptr += 2) {
      dct36(fs_in[sb], out1, out2, mpa->tables.win[0][bt], tsptr);
      dct36(fs_in[sb + 1], out1 + SSLIMIT, out2 + SSLIMIT, mpa->tables.win[1][bt], tsptr + 1);
    }
  }
  for (; sb < SBLIMIT; sb++, tsptr++) {
    register int i;
    for (i = 0; i < SSLIMIT; i++) {
      tsptr[i*SBLIMIT] = *out1++;
      *out2++ = 0.0;
    }
  }
}

void decode_layer3(mpadec_t mpadec, uint8_t *buffer)
{
  register struct mpadec_t *mpa = (struct mpadec_t *)mpadec;
  uint8_t *saved_next_byte = mpa->next_byte;
  uint32_t saved_bytes_left = mpa->bytes_left;
  int32_t dbits, scalefacs[2][39];
  int ch, gr, ss, i_stereo, ms_stereo, single, channels, granules = mpa->frame.LSF ? 1 : 2;

  mpa->error = FALSE;
  mpa->bits_left = 0;
  if (mpa->config.crc && mpa->frame.CRC) {
    mpa->crc = update_crc(mpa->crc, mpa->next_byte, mpa->ssize << 3);
    if (mpa->crc != mpa->frame.crc) mpa->error = TRUE;
  }
  dbits = decode_layer3_sideinfo(mpa);
  mpa->dsize = (((dbits < 0) ? 0 : dbits) + 7) >> 3;
  mpa->next_byte = saved_next_byte + mpa->ssize;
  mpa->bytes_left = saved_bytes_left - mpa->ssize;
  mpa->bits_left = 0;
  saved_next_byte = NULL;
  saved_bytes_left = mpa->bytes_left;
  if (mpa->error) mpa->sideinfo.main_data_begin = mpa->reservoir_size + 1;
  if (mpa->sideinfo.main_data_begin) {
    if (mpa->sideinfo.main_data_begin <= mpa->reservoir_size) {
      uint8_t *ptr = mpa->reservoir + mpa->reservoir_size;
      uint32_t tmp = mpa->frame.frame_size - mpa->hsize - mpa->ssize;
      if (tmp > (sizeof(mpa->reservoir) - mpa->reservoir_size)) tmp = sizeof(mpa->reservoir) - mpa->reservoir_size;
      saved_next_byte = mpa->next_byte;
      memcpy(ptr, mpa->next_byte, tmp);
      mpa->next_byte = ptr - mpa->sideinfo.main_data_begin;
      mpa->bytes_left = mpa->sideinfo.main_data_begin + tmp;
    } else {
      uint32_t tmp = mpa->frame.frame_size - mpa->hsize - mpa->ssize;
      if (tmp > 512) {
        mpa->next_byte += tmp - 512;
        mpa->bytes_left -= tmp - 512;
        tmp = 512;
      }
      if ((mpa->reservoir_size) && (mpa->reservoir_size > 512)) {
        memmove(mpa->reservoir, mpa->reservoir + mpa->reservoir_size - 512, 512);
        mpa->reservoir_size = 512;
      }
      memcpy(mpa->reservoir + mpa->reservoir_size, mpa->next_byte, tmp);
      mpa->reservoir_size += tmp;
      mpa->next_byte += tmp;
      mpa->bytes_left -= tmp;
      memset(buffer, 0, mpa->frame.decoded_size);
      mpa->error = TRUE;
      return;
    }
  }
  if (mpa->frame.mode == MPG_MD_JOINT_STEREO) {
    i_stereo = mpa->frame.mode_ext & 1;
    ms_stereo = (mpa->frame.mode_ext & 2) >> 1;
  } else i_stereo = ms_stereo = 0;
  if (mpa->frame.channels > 1) switch (mpa->config.mode) {
    case MPADEC_CONFIG_MONO:     single = 0; break;
    case MPADEC_CONFIG_CHANNEL1: single = 1; break;
    case MPADEC_CONFIG_CHANNEL2: single = 2; break;
    default:                     single = -1; break;
  } else single = 1;
  channels = (single < 0) ? 2 : 1;
  for (gr = 0; gr < granules; gr++) {
    grinfo_t *grinfo = &mpa->sideinfo.ch[0].gr[gr];
    int32_t part2bits = III_get_scale_factors(mpa, grinfo, scalefacs[0]);
    if (III_decode_samples(mpa, grinfo, mpa->hybrid_in[0], scalefacs[0], part2bits)) {
      unsigned size = mpa->frame.decoded_size;
      if (!mpa->frame.LSF && gr) size >>= 1;
      memset(buffer, 0, size);
      mpa->error = TRUE;
      goto done;
    }
    if (mpa->frame.channels > 1) {
      grinfo = &mpa->sideinfo.ch[1].gr[gr];
      part2bits = III_get_scale_factors(mpa, grinfo, scalefacs[1]);
      if (III_decode_samples(mpa, grinfo, mpa->hybrid_in[1], scalefacs[1], part2bits)) {
        unsigned size = mpa->frame.decoded_size;
        if (!mpa->frame.LSF && gr) size >>= 1;
        memset(buffer, 0, size);
        mpa->error = TRUE;
        goto done;
      }
      if (ms_stereo) {
        FLOAT *in0 = (FLOAT *)(mpa->hybrid_in[0]), *in1 = (FLOAT *)(mpa->hybrid_in[1]);
        unsigned i, maxb = mpa->sideinfo.ch[0].gr[gr].maxb;
        if (mpa->sideinfo.ch[1].gr[gr].maxb > maxb) maxb = mpa->sideinfo.ch[1].gr[gr].maxb;
        for (i = 0; i < SSLIMIT*maxb; i++) {
          register FLOAT tmp0 = in0[i];
          register FLOAT tmp1 = in1[i];
          in0[i] = tmp0 + tmp1;
          in1[i] = tmp0 - tmp1;
        }
      }
      if (i_stereo) III_i_stereo(mpa, grinfo, mpa->hybrid_in, scalefacs[1]);
      if (i_stereo || ms_stereo || !single) {
        if (grinfo->maxb > mpa->sideinfo.ch[0].gr[gr].maxb) mpa->sideinfo.ch[0].gr[gr].maxb = grinfo->maxb;
        else grinfo->maxb = mpa->sideinfo.ch[0].gr[gr].maxb;
      }
      if (!single) {
        register unsigned i;
        FLOAT *in0 = (FLOAT *)(mpa->hybrid_in[0]), *in1 = (FLOAT *)(mpa->hybrid_in[1]);
        for (i = 0; i < SSLIMIT*grinfo->maxb; i++, in0++) *in0 = (*in0 + *in1++);
      } else if (single == 2) {
        register unsigned i;
        FLOAT *in0 = (FLOAT *)(mpa->hybrid_in[0]), *in1 = (FLOAT *)(mpa->hybrid_in[1]);
        for (i = 0; i < SSLIMIT*grinfo->maxb; i++, in0++) *in0 = *in1++;
      }
    }
    for (ch = 0; ch < channels; ch++) {
      grinfo = &mpa->sideinfo.ch[ch].gr[gr];
      III_antialias(grinfo, mpa->hybrid_in[ch]);
      III_hybrid(mpa, grinfo, mpa->hybrid_in[ch], mpa->hybrid_out[ch], ch);
    }
    if (single < 0) {
      for (ss = 0; ss < SSLIMIT; ss++, (uint8_t *)buffer += mpa->synth_size) {
        mpa->synth_func(mpa, mpa->hybrid_out[0][ss], 0, buffer);
        mpa->synth_func(mpa, mpa->hybrid_out[1][ss], 1, buffer);
      }
    } else {
      for (ss = 0; ss < SSLIMIT; ss++, (uint8_t *)buffer += mpa->synth_size) {
        mpa->synth_func(mpa, mpa->hybrid_out[0][ss], 0, buffer);
      }
    }
  }
done:
  {
    register unsigned n = mpa->bits_left >> 3;
    mpa->next_byte -= n;
    mpa->bytes_left += n;
    if (saved_next_byte) {
      uint32_t tmp = mpa->frame.frame_size - mpa->hsize - mpa->ssize;
      if (mpa->bytes_left) {
        if (mpa->bytes_left > 512) {
          mpa->next_byte += mpa->bytes_left - 512;
          mpa->bytes_left = 512;
        }
        memmove(mpa->reservoir, mpa->next_byte, mpa->bytes_left);
        mpa->reservoir_size = mpa->bytes_left;
      } else mpa->reservoir_size = 0;
      mpa->next_byte = saved_next_byte + tmp;
      mpa->bytes_left = saved_bytes_left - tmp;
    } else {
      uint32_t tmp = mpa->frame.frame_size - mpa->hsize - mpa->ssize;
      mpa->reservoir_size = 0;
      if (tmp > (saved_bytes_left - mpa->bytes_left)) {
        tmp -= saved_bytes_left - mpa->bytes_left;
        if (tmp > 512) {
          mpa->next_byte += tmp - 512;
          mpa->bytes_left -= tmp - 512;
          tmp = 512;
        }
        memcpy(mpa->reservoir, mpa->next_byte, tmp);
        mpa->reservoir_size = tmp;
        mpa->next_byte += tmp;
        mpa->bytes_left -= tmp;
      }
    }
  }
}