/*

	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

		for(k=0;k

		for(l=0;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<

	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=alloc1->bits;

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

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

		}

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

		{

			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=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

	{

		step = alloc1->bits;

		for(j=0;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

	{

		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

	for (j=0;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

	{

		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 */