#include <stdio.h>
#include <math.h>
#include <fcntl.h>

int fd;
int steps;
int sf, nf; /* samples per fundamental, no of fundamentals */
float ff;   /* fundamental freq. relative to 440 Hz ('A')  */

#define MAXLENGTH 10*44100         /* 10 sec. samples enough ? */
#define MSEC(t) (int)(t*44.1)
short os[MAXLENGTH];

compute_sample(ff,sf,nf,argc,argv)
float ff;
int sf, nf;
int argc;
char *argv[];
{
   int s, h;
   float f, a;
   for (h=4; h< argc; h+=2) {
      sscanf(argv[h],"%f",&f);
      sscanf(argv[h+1],"%f",&a);
      printf(" ff %f steps %d sf %d nf %d  f %f a %f",
              ff,steps,sf,nf,f,a);
      for (s=0; s<sf*nf; s++)
        os[s] += (short) (32000.0* a *
           sin((double) (2*PI*f*s) / (double) sf)  );
   }
}


iwrite(fd,n,l)
int fd,l;
unsigned int n;
{
   write(fd,&n,l);
}

int initwav(s)                 /* Proto wav header, n=nnodes, filename */
char *s;
{
   fd = open(s,O_WRONLY|O_CREAT|O_TRUNC|O_BINARY);
   if (fd == NULL) return(-1);

   write(fd,"RIFF",4);
   iwrite(fd,(2*steps+36),4);
   write(fd,"WAVE",4);

   write(fd,"fmt ",4);
   iwrite(fd,(0x10),4);
   iwrite(fd,((short) 0x01),2);
   iwrite(fd,((short) 1),2);              /* Mono */
   iwrite(fd,(44100/1),4);                  /* Sample rate */
   iwrite(fd,(2*44100/1),4);
   iwrite(fd,((short) 2),2);
   iwrite(fd,((short) 16),2);

   write(fd,"data",4);
   iwrite(fd,(2*steps),4);
   return(0);
}


writewav(fd)
{
   int i;

   for (i=0; i<steps; i++)
      write(fd,&os[i],2);
   close(fd);
}

clear_os()
{
   int i;
   for (i=0; i<steps; i++)
       os[i] = 0;
}

int main(argc,argv)
int argc;
char *argv[];
{
   if (argc < 6 || ((argc-4)%2 != 0)) {
      printf("Usage %s <sound.wav> <fundamental relative to 440Hz> <no of funds>",argv[0]);
      printf("         {harmonic relative_ampl} ...\n");
      exit(-1);
   }
   sscanf(argv[2],"%f",&ff);
   sf = (int) ((44100.0) / (440.0 * ff));
   sscanf(argv[3],"%d",&nf);
   steps = nf*sf;
   if (steps > MAXLENGTH) {
      printf("Error: sample length of %d ms exceeds %d ms.\n",
         (1000*steps)/44100, (1000 *MAXLENGTH)/44100);
   }
   if (initwav(argv[1]) < 0) {
      printf("Error: cannot open file %s.\n",argv[1]);
   }
   clear_os();
   compute_sample(ff,sf,nf,argc,argv);
   writewav(fd);
   return(0);
}