--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoders/libmpg123/layer2.c	Fri Jan 30 02:44:47 2009 -0500
@@ -0,0 +1,335 @@
+/*
+	layer2.c: the layer 2 decoder, root of mpg123
+
+	copyright 1994-2007 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...
+*/
+
+
+#include "mpg123lib_intern.h"
+#include "l2tables.h"
+#include "getbits.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 */
+
+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
+};
+
+void init_layer2(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_layer2_stuff(mpg123_handle *fr)
+{
+  int k;
+  real *table;
+  for(k=0;k<27;k++)
+  {
+    table = opt_init_layer2_table(fr)(fr, fr->muls[k], mulmul[k]);
+    *table++ = 0.0;
+  }
+}
+
+real* init_layer2_table(mpg123_handle *fr, real *table, double m)
+{
+	int i,j;
+	for(j=3,i=0;i<63;i++,j--)
+	*table++ = m * pow(2.0,(double) j / 3.0);
+
+	return table;
+}
+
+#ifdef OPT_MMXORSSE
+real* init_layer2_table_mmx(mpg123_handle *fr, real *table, double m)
+{
+	int i,j;
+	if(!fr->p.down_sample) 
+	for(j=3,i=0;i<63;i++,j--)
+	*table++ = 16384 * m * pow(2.0,(double) j / 3.0);
+	else
+	for(j=3,i=0;i<63;i++,j--)
+	*table++ = m * pow(2.0,(double) j / 3.0);
+
+	return table;
+}
+#endif
+
+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;
+    /* static unsigned int scfsi_buf[64]; */
+		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;
+        }
+
+}
+
+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) ((int)getbits(fr, k) + d1)) * cm;
+            fraction[j][1][i] = ((real) ((int)getbits(fr, k) + d1)) * cm;
+            fraction[j][2][i] = ((real) ((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] = fr->muls[*tab++][m];
+            fraction[j][1][i] = fr->muls[*tab++][m];
+            fraction[j][2][i] = fr->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)
+        {
+          real cm;
+          cm=fr->muls[k][scale[x1+3]];
+          fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(fr, k) + d1) ) * cm;
+          fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(fr, k) + d1) ) * cm;
+          fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(fr, k) + d1) ) * cm;
+          cm=fr->muls[k][scale[x1]];
+          fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; 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] = fr->muls[*tab][m1]; fraction[1][0][i] = fr->muls[*tab++][m2];
+          fraction[0][1][i] = fr->muls[*tab][m1]; fraction[1][1][i] = fr->muls[*tab++][m2];
+          fraction[0][2][i] = fr->muls[*tab][m1]; fraction[1][2][i] = 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] = 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(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;
+  ALIGNED(16) 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) {
+	  fprintf(stderr, "Truncating stereo boundary to sideband limit.\n");
+	  fr->jsbound=fr->II_sblimit;
+  }
+  
+  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) (fraction[0][j], 0, fr, 0);
+        clip += (fr->synth) (fraction[1][j], 1, fr, 1);
+      }
+    }
+  }
+
+  return clip;
+}
+
+