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C/C++ Source or Header  |  1999-04-22  |  18KB  |  512 lines
  1. /* Public domain .ra/28_8 file decoder v2.0 */
  2.  
  3. /* Usage: radecode2 <file.ra >output.dat */
  4. /* Output is signed 16-bit audio data, 8khz */
  5.  
  6. #include <stdio.h>
  7. #include <stdlib.h>
  8. #include <math.h>
  9.  
  10. int dart_open();
  11. void dart_close(void);
  12. void dart_flush();
  13. void dart_put(short *buff, int count);
  14.  
  15. void deinterleave(unsigned char *in,unsigned char *out);
  16. void decodeblock(char *in,short int *out);
  17. void unpack(unsigned short *tgt,unsigned char *src,int len);
  18. void decode(unsigned int input);
  19. void update(void);
  20. void colmult(float *tgt,float *m1,float *m2,int n);
  21. int pred(float *in,float *tgt,int n);
  22. void co(int n,int i,int j,float *in,float *out,float *st1,float *st2,float *table);
  23. void prodsum(float *tgt,float *src,int len,int n);
  24.  
  25. /* globals */
  26. static float history[8];
  27. static float output[40];
  28. static float pr1[36];
  29. static float pr2[10];
  30. static int phase,phasep;
  31.  
  32. #define BLOCK_SIZE 50
  33. void ra288(FILE *fdo,FILE *fd,FILE *fdl)
  34. {
  35.   unsigned char in[2736];
  36.   unsigned char deint[2736];
  37.   signed short *out;
  38.   int x,s;
  39.   int cc=0,total=0;
  40.  
  41.   out=malloc(160*sizeof(short)*BLOCK_SIZE);
  42.   if (!out) return;
  43.   if (!fdo) if (dart_open()) return;
  44.  
  45.   while(fread(in,1,2736,fd)>0) {
  46.      deinterleave(in,deint);
  47.      for(x=0;x<72;x++){
  48.         decodeblock(deint+38*x,out+cc*160);
  49.         cc++;
  50.         total++;
  51.         if (cc==BLOCK_SIZE) {
  52.            fprintf(fdl,"\rdecoding: %u:%02u",(total/50)/60,(total/50)%60);
  53.            if (fdo) fwrite(out,320*cc,1,fdo);
  54.            else dart_put(out,160*cc);
  55.            cc=0;
  56.            }
  57.         }
  58.      }
  59. if (cc) {
  60.    if (fdo) fwrite(out,320*cc,1,fdo);
  61.    else dart_put(out,160*cc);
  62.    }
  63. if (!fdo) {
  64.    fprintf(fdl,"\rdecoded: %u:%02u, waiting for playback to finish",
  65.            (total/50)/60,(total/50)%60);
  66.    dart_flush();
  67.    dart_close();
  68.    }
  69. }
  70.  
  71. /* Unlike the 14.4 format, 28.8 blocks are interleaved */
  72. /* to dilute the effects of transmission errors */
  73. void deinterleave(unsigned char *in,unsigned char *out)
  74. {
  75.   unsigned int x=0,y=0;
  76.   while(x<2736)
  77.   {
  78.     memcpy(out+y,in+x,38);
  79.     x+=38;y+=456;
  80.     if(y>=2736) y-=2698;
  81.   }
  82. }
  83.  
  84. /* Decode a block (celp) */
  85. void decodeblock(char *in,short int *out)
  86. {
  87.   int x,y;
  88.   unsigned short int buffer[32];
  89.  
  90.   unpack(buffer,in,32);
  91.   for(x=0;x<32;x++)
  92.   {
  93.     phasep=(phase=x&7)*5;
  94.     decode(buffer[x]);
  95.     for(y=0;y<5;y++) *(out++)=8*output[phasep+y];
  96.     if(phase==3) update();
  97.   }
  98. }
  99.  
  100. /* initial decode */
  101. void unpack(unsigned short *tgt,unsigned char *src,int len)
  102. {
  103.   int x,y,z;
  104.   int n,temp;
  105.   int buffer[38];
  106.  
  107.   for(x=0;x<len;x++) {
  108.     tgt[x]=0;
  109.     buffer[x]=9+(x&1);
  110.   }
  111.  
  112.   for(x=y=z=0;x<38;x++) {
  113.     n=buffer[y]-z;
  114.     temp=src[x];
  115.     if(n<8) temp&=255>>(8-n);
  116.     tgt[y]+=temp<<z;
  117.     if(n<=8) {
  118.       tgt[++y]+=src[x]>>n;
  119.       z=8-n;
  120.     } else z+=8;
  121.   }
  122. }
  123.  
  124. float amptable[8]={0.515625,0.90234375,1.57910156,2.76342773,
  125.                -0.515625,-0.90234375,-1.57910156,-2.76342773};
  126.  
  127. float codetable[640]={
  128.  
  129. 0.326171875,-1.4404296875,-0.6123046875,-0.8740234375,-1.24658203125,
  130.   -2.45703125,-2.23486328125,-0.51025390625,1.419921875,1.6201171875,
  131.  
  132. -1.37646484375,-1.30712890625,-0.462890625,-1.37939453125,-2.1728515625,
  133.   -3.26123046875,-0.166015625,0.7236328125,-0.623046875,0.6162109375,
  134.  
  135. -0.2744140625,-3.29931640625,0.62548828125,0.08740234375,-0.6220703125,
  136.   -1.2265625,-3.4814453125,-2.40478515625,3.37548828125,1.17724609375,
  137.   -1.2099609375,-0.076171875,2.28662109375,-1.89111328125,0,
  138.   -4.0078125,1.044921875,-0.2333984375,-1.35986328125,0.26025390625,
  139.  
  140. 0.92236328125,1.34716796875,0.67431640625,-3.39599609375,-2.88720703125,
  141.   2.4814453125,-1.201171875,-2.8212890625,0.87744140625,0.27734375,
  142.   -1.078125,-1.61572265625,-2.20849609375,-3.044921875,-3.66455078125,
  143.   -1.32763671875,2.1279296875,-1.458984375,-0.56103515625,1.30078125,
  144.   0.61474609375,0.48583984375,1.32373046875,-1.203125,-5.0732421875,
  145.  
  146. 0.8408203125,-3.69580078125,-1.3388671875,1.06005859375,-1.13720703125,
  147.   0.50390625,0.36474609375,-0.4189453125,-3.8798828125,-6.27099609375,
  148.   1.5166015625,2.37109375,-2.04736328125,-1.24072265625,0.50537109375,
  149.   0.9091796875,-0.46875,-3.236328125,0.2001953125,2.8720703125,
  150.   -1.21728515625,-1.283203125,-1.953125,-0.029296875,3.5166015625,
  151.   -1.3046875,0.7060546875,0.75,-1.87060546875,0.60205078125,
  152.   -2.5888671875,3.375,0.77587890625,-2.04443359375,1.78955078125,
  153.   -1.6875,-3.9892578125,-3.76416015625,0.67578125,2.2939453125,
  154.   -2.29443359375,-3.03173828125,-5.45703125,3.95703125,8.2177734375,
  155.   0.4541015625,3.419921875,0.61962890625,-4.38330078125,1.25341796875,
  156.  
  157. 2.27001953125,5.763671875,1.68017578125,-2.76220703125,0.58544921875,
  158.   1.2412109375,-0.08935546875,-4.32568359375,-3.89453125,1.5771484375,
  159.  
  160. -1.40234375,-0.98193359375,-4.74267578125,-4.09423828125,6.33935546875,
  161.   1.5068359375,1.044921875,-1.796875,-4.70849609375,-1.4140625,
  162.  
  163. -3.71533203125,3.18115234375,-1.11474609375,-1.2314453125,3.091796875,
  164.  
  165. -1.62744140625,-2.744140625,-4.4580078125,-5.43505859375,2.70654296875,
  166.  
  167. -0.19873046875,-3.28173828125,-8.5283203125,-1.41064453125,5.6484375,
  168.   1.802734375,3.318359375,-0.1279296875,-5.2958984375,-0.90625,
  169.   3.55224609375,6.544921875,-1.45947265625,-5.17333984375,2.41015625,
  170.   0.119140625,-1.08349609375,1.296875,1.84375,-2.642578125,
  171.  
  172. -1.97412109375,-2.8974609375,1.04052734375,0.42138671875,-1.3994140625,
  173.   -1.6123046875,0.85107421875,-0.9794921875,-0.0625,-1.001953125,
  174.  
  175. -3.10595703125,1.6318359375,-0.77294921875,-0.01025390625,0.5576171875,
  176.   -1.87353515625,-0.89404296875,3.12353515625,1.24267578125,-1.390625,
  177.   -4.556640625,-3.1875,2.59228515625,0.9697265625,-1.09619140625,
  178.  
  179. -2.1923828125,0.365234375,0.94482421875,-1.47802734375,-0.24072265625,
  180.   -4.51904296875,2.6201171875,1.55908203125,-2.19384765625,0.87109375,
  181.   2.3359375,-0.1806640625,0.9111328125,0.51611328125,-0.92236328125,
  182.  
  183. 3.5849609375,-1.3134765625,-1.25830078125,0.330078125,-0.29833984375,
  184.  
  185. -0.2451171875,1.09130859375,-0.9033203125,-0.86767578125,-1.00048828125,
  186.   0.49365234375,1.89453125,-1.20361328125,1.07861328125,-0.07421875,
  187.   1.265625,1.38134765625,2.728515625,1.38623046875,-3.5673828125,
  188.  
  189. -1.48876953125,-2.4013671875,2.90771484375,4.49267578125,-2.17138671875,
  190.   0.34033203125,1.908203125,2.8310546875,-2.17333984375,-2.267578125,
  191.  
  192. -1.03564453125,2.658203125,-1.2548828125,0.15673828125,-0.5869140625,
  193.   1.3896484375,-1.0185546875,1.724609375,0.2763671875,-0.345703125,
  194.   -2.08935546875,0.4638671875,2.431640625,1.83056640625,0.220703125,
  195.   -1.212890625,1.7099609375,0.83935546875,-0.0830078125,0.1162109375,
  196.  
  197. -1.67724609375,0.12841796875,1.0322265625,-0.97900390625,1.15283203125,
  198.   -3.5830078125,-0.58984375,4.56396484375,-0.59375,-1.95947265625,
  199.   -6.5908203125,-0.21435546875,3.919921875,-2.06640625,0.17626953125,
  200.  
  201. -1.82080078125,2.65283203125,0.978515625,-2.30810546875,-0.61474609375,
  202.  
  203. -1.9462890625,3.78076171875,4.11572265625,-1.80224609375,-0.48193359375,
  204.   2.5380859375,-0.20654296875,0.5615234375,-0.62548828125,0.3984375,
  205.  
  206. 3.61767578125,2.00634765625,-1.92822265625,1.3134765625,0.0146484384313,
  207.  
  208. 0.6083984375,1.49169921875,-0.01708984375,-0.6689453125,-0.1201171875,
  209.  
  210. -0.72705078125,2.75146484375,-0.3310546875,-1.28271484375,1.5478515625,
  211.   2.3583984375,-2.23876953125,0.98046875,-0.5185546875,0.39013671875,
  212.  
  213. -0.06298828125,0.35009765625,2.2431640625,7.29345703125,5.2275390625,
  214.  
  215. 0.20361328125,1.34716796875,0.9033203125,-2.46923828125,-0.56298828125,
  216.   -1.89794921875,3.59423828125,-2.81640625,2.09228515625,0.3251953125,
  217.  
  218. 0.70458984375,-0.4580078125,0.009765625,-1.03466796875,-0.82861328125,
  219.   -1.8125,-1.6611328125,-1.080078125,0.0537109375,1.04296875,
  220.   -1.44140625,0.005859375,-0.765625,-1.708984375,-0.90576171875,
  221.  
  222. -0.64208984375,-0.84521484375,0.56640625,-0.2724609375,0.83447265625,
  223.   0.04296875,-2.23095703125,0.0947265625,-0.2216796875,-1.44384765625,
  224.  
  225. -1.38623046875,-0.8134765625,-0.13330078125,1.017578125,-0.07568359375,
  226.   -0.09228515625,-1.16015625,0.81201171875,-0.5078125,-1.19580078125,
  227.   -1.3876953125,-0.66845703125,0.310546875,-0.12109375,-1.30712890625,
  228.  
  229. 0.74072265625,0.03857421875,-1.47119140625,-1.79150390625,-0.47509765625,
  230.   0.93408203125,-1.21728515625,-2.59375,-0.36572265625,0.62060546875,
  231.  
  232. -1.41748046875,-1.623046875,-1.833984375,-1.8017578125,-0.89306640625,
  233.   -1.42236328125,-0.75537109375,-1.34765625,-0.6865234375,0.548828125,
  234.   0.900390625,-0.8955078125,0.22265625,0.3447265625,-2.0859375,
  235.   0.22802734375,-2.078125,-0.93212890625,0.74267578125,0.5537109375,
  236.  
  237. -0.06201171875,-0.4853515625,-0.31103515625,-0.72802734375,-3.1708984375,
  238.   0.42626953125,-0.99853515625,-1.869140625,-1.36328125,-0.2822265625,
  239.   1.12841796875,-0.88720703125,1.28515625,-1.490234375,0.9609375,
  240.   0.31298828125,0.5830078125,0.92431640625,2.00537109375,3.0966796875,
  241.   -0.02197265625,0.5849609375,1.0546875,-0.70751953125,1.07568359375,
  242.   -0.978515625,0.83642578125,1.7177734375,1.294921875,2.07568359375,
  243.   1.43359375,-1.9375,0.625,0.06396484375,-0.720703125,
  244.   1.38037109375,0.00390625,-0.94140625,1.2978515625,1.71533203125,
  245.  
  246. 1.56201171875,-0.3984375,1.31201171875,-0.85009765625,-0.68701171875,
  247.   1.439453125,1.96728515625,0.1923828125,-0.12353515625,0.6337890625,
  248.   2.0927734375,0.02490234375,-2.20068359375,-0.015625,-0.32177734375,
  249.   1.90576171875,2.7568359375,-2.728515625,-1.265625,2.78662109375,
  250.   -0.2958984375,0.6025390625,-0.78466796875,-2.53271484375,0.32421875,
  251.   -0.25634765625,1.767578125,-1.0703125,-1.23388671875,0.83349609375,
  252.   2.09814453125,-1.58740234375,-1.11474609375,0.396484375,-1.10546875,
  253.   2.81494140625,0.2578125,-1.60498046875,0.66015625,0.81640625,
  254.  
  255. 1.33544921875,0.60595703125,-0.53857421875,-1.59814453125,-1.66357421875,
  256.   1.96923828125,0.8046875,-1.44775390625,-0.5732421875,0.705078125,
  257.   0.0361328125,0.4482421875,0.97607421875,0.44677734375,-0.5009765625,
  258.   -1.21875,-0.78369140625,0.9931640625,1.4404296875,0.11181640625,
  259.   -1.05859375,0.99462890625,0.00732421921566,-0.6171875,-0.1015625,
  260.   -1.734375,0.7470703125,0.28369140625,0.72802734375,0.4697265625,
  261.  
  262. -1.27587890625,-1.1416015625,1.76806640625,-0.7265625,-1.06689453125,
  263.   -0.85302734375,0.03955078125,2.7041015625,0.69921875,-1.10205078125,
  264.  
  265. -0.49755859375,0.42333984375,0.1044921875,-1.115234375,-0.7373046875,
  266.   -0.822265625,1.375,-0.11181640625,1.24560546875,-0.67822265625,
  267.   1.32177734375,0.24609375,0.23388671875,1.35888671875,-0.49267578125,
  268.  
  269. 1.22900390625,-0.72607421875,-0.779296875,0.30322265625,0.94189453125,
  270.   -0.072265625,1.0771484375,-2.09375,0.630859375,-0.68408203125,
  271.   -0.25732421875,0.60693359375,-1.33349609375,0.93212890625,0.625,
  272.   1.04931640625,-0.73291015625,1.80078125,0.2978515625,-2.24169921875,
  273.  
  274. 1.6142578125,-1.64501953125,0.91552734375,1.775390625,-0.59423828125,
  275.  
  276. 1.2568359375,1.22705078125,0.70751953125,-1.5009765625,-2.43115234375,
  277.  
  278. 0.3974609375,0.8916015625,-1.21923828125,2.0673828125,-1.99072265625,
  279.   0.8125,-0.107421875,1.6689453125,0.4892578125,0.54443359375,
  280.   0.38134765625,0.8095703125,1.91357421875,2.9931640625,1.533203125,
  281.   0.560546875,1.98486328125,0.740234375,0.39794921875,0.09716796875,
  282.  
  283. 0.58154296875,1.21533203125,1.25048828125,1.18212890625,1.19287109375,
  284.   0.3759765625,-2.88818359375,2.69287109375,-0.1796875,-1.56201171875,
  285.  
  286. 0.5810546875,0.51123046875,1.8271484375,3.38232421875,-1.02001953125,
  287.   0.142578125,1.51318359375,2.103515625,-0.3701171875,-1.19873046875,
  288.   0.25537109375,1.91455078125,1.974609375,0.6767578125,0.04150390625,
  289.  
  290. 2.13232421875,0.4912109375,-0.611328125,-0.7158203125,-0.67529296875,
  291.   1.880859375,0.77099609375,-0.03759765625,1.0078125,0.423828125,
  292.  
  293. 2.49462890625,1.42529296875,-0.0986328125,0.17529296875,-0.24853515625,
  294.   1.7822265625,1.5654296875,1.12451171875,0.82666015625,0.6328125,
  295.  
  296. 1.41845703125,-1.90771484375,0.11181640625,-0.583984375,-1.138671875,
  297.  
  298. 2.91845703125,-1.75048828125,0.39306640625,1.86767578125,-1.5322265625,
  299.  
  300. 1.8291015625,-0.2958984375,0.02587890625,-0.13134765625,-1.61181640625,
  301.   0.2958984375,0.9853515625,-0.642578125,1.984375,0.1943359375};
  302.  
  303. /* Decode and produce output */
  304. void decode(unsigned int input)
  305. {
  306.   unsigned int x,y;
  307.   float f;
  308.   double sum;
  309.   float *p1,*p2;
  310.   float buffer[5];
  311.   static float sb[41];
  312.   static float lhist[10];
  313.  
  314.   for(x=36;x--;) sb[x+5]=sb[x];
  315.   for(x=5;x--;) {
  316.     p1=sb+x;p2=pr1;
  317.     sum=0;for(y=36;y--;) sum-=(*(++p1))*(*(p2++));
  318.     sb[x]=sum;
  319.   }
  320.  
  321.   f=amptable[input&7];
  322.   p1=codetable+(input>>3)*5;
  323.  
  324.   /* convert log and do rms */
  325.   sum=32;for(x=10;x--;) sum-=pr2[x]*lhist[x];
  326.   if(sum<0) sum=0; else if(sum>60) sum=60;
  327.   for(x=5;x--;) buffer[x]=f*p1[x]*pow(10,sum/20);
  328.   sum=0;for(x=5;x--;) sum+=buffer[x]*buffer[x];
  329.   if((sum/=5)<1) sum=1;
  330.   /* shift and store */
  331.   for(x=10;--x;) lhist[x]=lhist[x-1];
  332.   *lhist=history[phase]=10*log10(sum)-32;
  333.   
  334.   for(x=1;x<5;x++) for(y=x;y--;) buffer[x]-=pr1[x-y-1]*buffer[y];
  335.  
  336.   /* output */
  337.   for (x=0;x<5;x++) {
  338.     f=sb[4-x]+buffer[x];
  339.     if(f>4095) f=4095; else if(f<-4095) f=-4095;
  340.     output[phasep+x]=sb[4-x]=f;
  341.   }
  342. }
  343.  
  344. float table1[111]={
  345.  
  346. 0.576690972,0.580838025,0.585013986,0.589219987,0.59345597,0.597723007,
  347.  
  348. 0.602020264,0.606384277,0.610748291,0.615142822,0.619598389,0.624084473,
  349.  
  350. 0.628570557,0.633117676,0.637695313,0.642272949,0.646911621,0.651580811,
  351.  
  352. 0.656280518,0.66104126,0.665802002,0.670593262,0.675445557,0.680328369,
  353.  
  354. 0.685241699,0.690185547,0.695159912,0.700164795,0.705230713,0.710327148,
  355.  
  356. 0.715454102,0.720611572,0.725830078,0.731048584,0.736328125,0.741638184,
  357.  
  358. 0.747009277,0.752380371,0.7578125,0.763305664,0.768798828,0.774353027,
  359.  
  360. 0.779937744,0.785583496,0.791229248,0.796936035,0.802703857,0.808502197,
  361.  
  362. 0.814331055,0.820220947,0.826141357,0.832092285,0.838104248,0.844146729,
  363.  
  364. 0.850250244,0.856384277,0.862548828,0.868774414,0.875061035,0.881378174,
  365.  
  366. 0.88772583,0.894134521,0.900604248,0.907104492,0.913635254,0.920227051,
  367.  
  368. 0.926879883,0.933563232,0.940307617,0.94708252,0.953918457,0.96081543,
  369.  
  370. 0.96774292,0.974731445,0.981781006,0.988861084,0.994842529,0.998565674,
  371.  
  372. 0.999969482,0.99911499,0.996002197,0.990600586,0.982910156,0.973022461,
  373.  
  374. 0.960876465,0.946533203,0.930053711,0.911437988,0.89074707,0.868041992,
  375.  
  376. 0.843322754,0.816680908,0.788208008,0.757904053,0.725891113,0.692199707,
  377.  
  378. 0.656921387,0.620178223,0.582000732,0.542480469,0.501739502,0.459838867,
  379.  
  380. 0.416900635,0.373016357,0.328277588,0.282775879,0.236663818,0.189971924,
  381.   0.142852783,0.0954284668,0.0477600098};
  382.  
  383. float table2[38]={
  384.  
  385. 0.505699992,0.524200022,0.54339999,0.563300014,0.583953857,0.60534668,
  386.  
  387. 0.627502441,0.650482178,0.674316406,0.699005127,0.724578857,0.75112915,
  388.  
  389. 0.778625488,0.807128906,0.836669922,0.86730957,0.899078369,0.932006836,
  390.   0.961486816,0.982757568,0.995635986,1,0.995819092,0.983154297,
  391.  
  392. 0.96206665,0.932769775,0.895507813,0.850585938,0.798400879,0.739379883,
  393.  
  394. 0.674072266,0.602996826,0.526763916,0.446014404,0.361480713,0.273834229,
  395.   0.183868408,0.0923461914};
  396.  
  397. float table1a[36]={
  398.  
  399. 0.98828125,0.976699829,0.965254128,0.953942537,0.942763507,0.931715488,
  400.  
  401. 0.920796931,0.910006344,0.899342179,0.888803005,0.878387332,0.868093729,
  402.  
  403. 0.857920766,0.847867012,0.837931097,0.828111589,0.818407178,0.808816493,
  404.  
  405. 0.799338162,0.789970934,0.780713439,0.771564424,0.762522638,0.753586829,
  406.  
  407. 0.744755745,0.736028135,0.727402806,0.718878567,0.710454226,0.702128589,
  408.  
  409. 0.693900526,0.685768902,0.677732527,0.669790328,0.66194123,0.654184103};
  410.  
  411. float table2a[10]={
  412.   0.90625,0.821289063,0.74432373,0.674499512,0.61126709,
  413.   0.553955078,0.50201416,0.454956055,0.41229248,0.373657227};
  414.  
  415. void update()
  416. {
  417.   int x,y;
  418.   float buffer1[40],temp1[37];
  419.   float buffer2[8],temp2[11];
  420.   static float st1a[111],st1b[37],st1[37];
  421.   static float st2a[38],st2b[11],st2[11];
  422.  
  423.   for(x=0,y=phasep+5;x<40;) buffer1[x++]=output[(y++)%40];
  424.   co(36,40,35,buffer1,temp1,st1a,st1b,table1);
  425.   if(pred(temp1,st1,36))
  426.     colmult(pr1,st1,table1a,36);
  427.  
  428.   for(x=0,y=phase+1;x<8;) buffer2[x++]=history[(y++)%8];
  429.   co(10,8,20,buffer2,temp2,st2a,st2b,table2);
  430.   if(pred(temp2,st2,10))
  431.     colmult(pr2,st2,table2a,10);
  432. }
  433.  
  434. /* column multiply */
  435. void colmult(float *tgt,float *m1,float *m2,int n)
  436. {
  437.   while(n--)
  438.     *(tgt++)=(*(m1++))*(*(m2++));
  439. }
  440.  
  441. int pred(float *in,float *tgt,int n)
  442. {
  443.   int x,y;
  444.   float *p1,*p2;
  445.   double f0,f1,f2;
  446.   float temp;
  447.  
  448.   if(in[n]==0) return 0;
  449.   if((f0=*in)<=0) return 0;
  450.  
  451.   for(x=1;1;x++){
  452.     if (n<x) return 1;
  453.  
  454.     p1=in+x;
  455.     p2=tgt;
  456.     f1=*(p1--);
  457.     for(y=x;--y;) f1+=(*(p1--))*(*(p2++));
  458.  
  459.     p1=tgt+x-1;
  460.     p2=tgt;
  461.     *(p1--)=f2=-f1/f0;
  462.     for(y=x>>1;y--;) {
  463.       temp=*p2+*p1*f2;
  464.       *(p1--)+=*p2*f2;
  465.       *(p2++)=temp;
  466.     }
  467.     if((f0+=f1*f2)<0) return 0;
  468.   }
  469. }
  470.  
  471. void co(int n,int i,int j,float *in,float *out,float *st1,float *st2,float *table)
  472. {
  473.   int a,b,c;
  474.   unsigned int x;
  475.   float *fp,*fp2;
  476.   float buffer1[37];
  477.   float buffer2[37];
  478.   float work[111];
  479.  
  480.   /* rotate and multiply */
  481.   c=(b=(a=n+i)+j)-i;
  482.   fp=st1+i;
  483.   for(x=0;x<b;x++) {
  484.     if (x==c) fp=in;
  485.     work[x]=*(table++)*(*(st1++)=*(fp++));
  486.   }
  487.   
  488.   prodsum(buffer1,work+n,i,n);
  489.   prodsum(buffer2,work+a,j,n);
  490.  
  491.   for(x=0;x<=n;x++) {
  492.     *st2=*st2*(0.5625)+buffer1[x];
  493.     out[x]=*(st2++)+buffer2[x];
  494.   }
  495.   *out*=1.00390625; /* to prevent clipping */
  496. }
  497.  
  498. /* product sum (lsf) */
  499. void prodsum(float *tgt,float *src,int len,int n)
  500. {
  501.   unsigned int x;
  502.   float *p1,*p2;
  503.   double sum;
  504.  
  505.   while(n>=0)
  506.   {
  507.     sum=0;
  508.     p1=(p2=src)-n;
  509.     for(x=len;x--;) sum+=(*p1++)*(*p2++);
  510.     tgt[n--]=sum;
  511.   }
  512. }