59 lines
1.5 KiB
C
59 lines
1.5 KiB
C
/*
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The function to compute the layer I and II tables at runtime or for pregeneration.
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copyright ?-2021 by the mpg123 project - free software under the terms of the LGPL 2.1
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see COPYING and AUTHORS files in distribution or http://mpg123.org
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initially written by Michael Hipp (in layer2.c).
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The type clreal is either double or float. POW() is pow() or powf().
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*/
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void init_layer12(void)
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{
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const clreal mulmul[27] =
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{
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0.0 , -2.0/3.0 , 2.0/3.0 ,
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2.0/7.0 , 2.0/15.0 , 2.0/31.0, 2.0/63.0 , 2.0/127.0 , 2.0/255.0 ,
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2.0/511.0 , 2.0/1023.0 , 2.0/2047.0 , 2.0/4095.0 , 2.0/8191.0 ,
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2.0/16383.0 , 2.0/32767.0 , 2.0/65535.0 ,
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-4.0/5.0 , -2.0/5.0 , 2.0/5.0, 4.0/5.0 ,
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-8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0
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};
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// void init_layer12_stuff()
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// real* init_layer12_table()
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for(int k=0;k<27;k++)
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{
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int i,j;
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clreal *table = layer12_table[k];
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for(j=3,i=0;i<63;i++,j--)
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*table++ = mulmul[k] * POW(2.0,(clreal) j / 3.0);
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*table++ = 0.0;
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}
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// void init_layer12()
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const unsigned char base[3][9] =
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{
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{ 1 , 0, 2 , } ,
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{ 17, 18, 0 , 19, 20 , } ,
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{ 21, 1, 22, 23, 0, 24, 25, 2, 26 }
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};
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int i,j,k,l,len;
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const int tablen[3] = { 3 , 5 , 9 };
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unsigned char *itable;
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unsigned char *tables[3] = { grp_3tab , grp_5tab , grp_9tab };
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for(i=0;i<3;i++)
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{
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itable = tables[i];
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len = tablen[i];
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for(j=0;j<len;j++)
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for(k=0;k<len;k++)
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for(l=0;l<len;l++)
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{
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*itable++ = base[i][l];
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*itable++ = base[i][k];
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*itable++ = base[i][j];
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}
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}
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}
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