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

#include <sys/types.h>

int fd;
FILE *fp;

int steps;

#define MAXLENGHT 1*1024*1024         /* 1 meg samples enough ? */
short dva[MAXLENGHT];


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),4);                  /* Sample rate */
   iwrite(fd,(2*44100),4);
   iwrite(fd,((short) 2),2);
   iwrite(fd,((short) 16),2);

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


outputbin(i)
int i;
{
   char *cp;
   int t;
   if (fd > 0) {
      /* t = e[i]/PREMUL; */
      cp = (char *) &t;
      write(fd,cp,1);
      write(fd,cp+1,1);
   }
}


read_convert(fp)
FILE *fp;
{
   float t, v, vmin, vmax;
   short dv, vdmin, vdmax;

   vmin=+1e6; vmax=-1e6;
   steps=0;
   while (fscanf(fp,"%f %f\n",&t,&v) == 2) {
      dv = (short) (10000.0 * v);
      /* puts(fd, &dv , 2); */
      steps++;
      if (v > vmax) { vmax=v; vdmax = dv;} ;
      if (v < vmin) { vmin=v; vdmin = dv;} ;
      if (v >= 3.2766) dv=32766;
      if (v <=-3.2766) dv=-32766;
      dva[steps] = dv;
   }
   fclose(fp);
   printf(" converted %d samples, max/min: %f(%d)  %f(%d)\n",steps,vmax,vdmax,vmin,vdmin);
}

writewav(fd)
{
   int i;

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


main(argc, argv)
int argc;
char *argv[];
{
   if (argc != 3) {
      printf("Usage: %s <infile> <outfile>\n",argv[0]);
      printf("(infile contains lines with (time sample) float tuplets,\n");
      printf("(outfile is a .wav soundfile).\n");
      exit(-1);
   }
   if ((fp = fopen(argv[1],"r")) == NULL) {
      printf("Cannot open input file %s.\n",argv[1]); exit(-2);
   }
   read_convert(fp);
   if (initwav(argv[2]) != 0) {
      printf("Cannot open output file %s.\n", argv[2]);
      exit(-3);
   }
   writewav(fd);
}