/*

layer2.c: the layer 2 decoder, root of mpg123

copyright 1994-2009 by the mpg123 project - free software under the terms of the LGPL 2.1

see COPYING and AUTHORS files in distribution or http://mpg123.org

initially written by Michael Hipp

mpg123 started as mp2 decoder a long time ago...

part of this file is required for layer 1, too.

*/

#include "mpg123lib_intern.h"

#ifndef NO_LAYER2

#include "l2tables.h"

#endif

#include "getbits.h"

#ifndef NO_LAYER12 /* Stuff needed for layer I and II. */

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 */

#if defined(REAL_IS_FIXED) && defined(PRECALC_TABLES)

#include "l12_integer_tables.h"

#else

static const 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

};

#endif

void init_layer12(void)

{

const 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;

const int tablen[3] = { 3 , 5 , 9 };

int *itable;

int *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];

}

}

}

void init_layer12_stuff(mpg123_handle *fr, real* (*init_table)(mpg123_handle *fr, real *table, int m))

{

int k;

real *table;

for(k=0;k<27;k++)

{

table = init_table(fr, fr->muls[k], k);

*table++ = 0.0;

}

}

real* init_layer12_table(mpg123_handle *fr, real *table, int m)

{

#if defined(REAL_IS_FIXED) && defined(PRECALC_TABLES)

int i;

for(i=0;i<63;i++)

*table++ = layer12_table[m][i];

#else

int i,j;

for(j=3,i=0;i<63;i++,j--)

*table++ = DOUBLE_TO_REAL_SCALE_LAYER12(mulmul[m] * pow(2.0,(double) j / 3.0));

#endif

return table;

}

#ifdef OPT_MMXORSSE

real* init_layer12_table_mmx(mpg123_handle *fr, real *table, int m)

{

int i,j;

if(!fr->p.down_sample)

{

for(j=3,i=0;i<63;i++,j--)

*table++ = DOUBLE_TO_REAL(16384 * mulmul[m] * pow(2.0,(double) j / 3.0));

}

else

{

for(j=3,i=0;i<63;i++,j--)

*table++ = DOUBLE_TO_REAL(mulmul[m] * pow(2.0,(double) j / 3.0));

}

return table;

}

#endif

#endif /* NO_LAYER12 */

/* The rest is the actual decoding of layer II data. */

#ifndef NO_LAYER2

static void II_step_one(unsigned int *bit_alloc,int *scale,mpg123_handle *fr)

{

int stereo = fr->stereo-1;

int sblimit = fr->II_sblimit;

int jsbound = fr->jsbound;

int sblimit2 = fr->II_sblimit<<stereo;

const struct al_table *alloc1 = fr->alloc;

int i;

unsigned int scfsi_buf[64];

unsigned int *scfsi,*bita;

int sc,step;

bita = bit_alloc;

if(stereo)

{

for(i=jsbound;i;i--,alloc1+=(1<<step))

{

step=alloc1->bits;

*bita++ = (char) getbits(fr, step);

*bita++ = (char) getbits(fr, step);

}

for(i=sblimit-jsbound;i;i--,alloc1+=(1<<step))

{

step=alloc1->bits;

bita[0] = (char) getbits(fr, step);

bita[1] = bita[0];

bita+=2;

}

bita = bit_alloc;

scfsi=scfsi_buf;

for(i=sblimit2;i;i--)

if(*bita++) *scfsi++ = (char) getbits_fast(fr, 2);

}

else /* mono */

{

for(i=sblimit;i;i--,alloc1+=(1<<step))

{

step=alloc1->bits;

*bita++ = (char) getbits(fr, step);

}

bita = bit_alloc;

scfsi=scfsi_buf;

for(i=sblimit;i;i--)

if(*bita++) *scfsi++ = (char) getbits_fast(fr, 2);

}

bita = bit_alloc;

scfsi=scfsi_buf;

for(i=sblimit2;i;i--)

if(*bita++)

switch(*scfsi++)

{

case 0:

*scale++ = getbits_fast(fr, 6);

*scale++ = getbits_fast(fr, 6);

*scale++ = getbits_fast(fr, 6);

break;

case 1 :

*scale++ = sc = getbits_fast(fr, 6);

*scale++ = sc;

*scale++ = getbits_fast(fr, 6);

break;

case 2:

*scale++ = sc = getbits_fast(fr, 6);

*scale++ = sc;

*scale++ = sc;

break;

default: /* case 3 */

*scale++ = getbits_fast(fr, 6);

*scale++ = sc = getbits_fast(fr, 6);

*scale++ = sc;

break;

}

}

static void II_step_two(unsigned int *bit_alloc,real fraction[2][4][SBLIMIT],int *scale,mpg123_handle *fr,int x1)

{

int i,j,k,ba;

int stereo = fr->stereo;

int sblimit = fr->II_sblimit;

int jsbound = fr->jsbound;

const 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)

{

real cm=fr->muls[k][scale[x1]];

fraction[j][0][i] = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15((int)getbits(fr, k) + d1), cm);

fraction[j][1][i] = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15((int)getbits(fr, k) + d1), cm);

fraction[j][2][i] = REAL_MUL_SCALE_LAYER12(DOUBLE_TO_REAL_15((int)getbits(fr, k) + d1), cm);

}

else

{

const 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) getbits(fr, k);

tab = (unsigned int *) (table[d1] + idx + idx + idx);

fraction[j][0][i] = REAL_SCALE_LAYER12(fr->muls[*tab++][m]);

fraction[j][1][i] = REAL_SCALE_LAYER12(fr->muls[*tab++][m]);

fraction[j][2][i] = REAL_SCALE_LAYER12(fr->muls[*tab][m]);

}

scale+=3;

}

else

fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = DOUBLE_TO_REAL(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)

{

real cm;

cm=fr->muls[k][scale[x1+3]];

fraction[0][0][i] = DOUBLE_TO_REAL_15((int)getbits(fr, k) + d1);

fraction[0][1][i] = DOUBLE_TO_REAL_15((int)getbits(fr, k) + d1);

fraction[0][2][i] = DOUBLE_TO_REAL_15((int)getbits(fr, k) + d1);

fraction[1][0][i] = REAL_MUL_SCALE_LAYER12(fraction[0][0][i], cm);

fraction[1][1][i] = REAL_MUL_SCALE_LAYER12(fraction[0][1][i], cm);

fraction[1][2][i] = REAL_MUL_SCALE_LAYER12(fraction[0][2][i], cm);

cm=fr->muls[k][scale[x1]];

fraction[0][0][i] = REAL_MUL_SCALE_LAYER12(fraction[0][0][i], cm);

fraction[0][1][i] = REAL_MUL_SCALE_LAYER12(fraction[0][1][i], cm);

fraction[0][2][i] = REAL_MUL_SCALE_LAYER12(fraction[0][2][i], cm);

}

else

{

const 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) getbits(fr, k);

tab = (unsigned int *) (table[d1] + idx + idx + idx);

fraction[0][0][i] = REAL_SCALE_LAYER12(fr->muls[*tab][m1]); fraction[1][0][i] = REAL_SCALE_LAYER12(fr->muls[*tab++][m2]);

fraction[0][1][i] = REAL_SCALE_LAYER12(fr->muls[*tab][m1]); fraction[1][1][i] = REAL_SCALE_LAYER12(fr->muls[*tab++][m2]);

fraction[0][2][i] = REAL_SCALE_LAYER12(fr->muls[*tab][m1]); fraction[1][2][i] = REAL_SCALE_LAYER12(fr->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] = DOUBLE_TO_REAL(0.0);

}

/*

Historic comment...

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] = DOUBLE_TO_REAL(0.0);

}

static void II_select_table(mpg123_handle *fr)

{

const 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;

const struct al_table *tables[5] = { alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 };

const int sblims[5] = { 27 , 30 , 8, 12 , 30 };

if(fr->sampling_frequency >= 3) /* Or equivalent: (fr->lsf == 1) */

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 do_layer2(mpg123_handle *fr)

{

int clip=0;

int i,j;

int stereo = fr->stereo;

/* pick_table clears unused subbands */

/* replacement for real fraction[2][4][SBLIMIT], needs alignment. */

real (*fraction)[4][SBLIMIT] = fr->layer2.fraction;

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)

{

fprintf(stderr, "Truncating stereo boundary to sideband limit.\n");

fr->jsbound=fr->II_sblimit;

}

/* TODO: What happens with mono mixing, actually? */

if(stereo == 1 || single == SINGLE_MIX) /* also, mix not really handled */

single = SINGLE_LEFT;

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 != SINGLE_STEREO)

clip += (fr->synth_mono)(fraction[single][j], fr);

else

clip += (fr->synth_stereo)(fraction[0][j], fraction[1][j], fr);

}

}

return clip;

}

#endif /* NO_LAYER2 */