/*

   An Emperical Approach to TCP/IP Sequence Number Analysis
   --------------------------------------------------------

   This utility is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   (C) 2001 Michal Zalewski <lcamtuf@razor.bindview.com>

*/

// To be honest, this code is crappy.

#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>


double itable[100000];
int cnt;

#define SCALING 0.5

int main(int argc, char *argv[]) {
  int num;
  double nth, n1th = 0, n2th = 0, n3th = 0;
  double x, y;
  double usex, usey, pha = 0;
  ssize_t len;
  size_t size;
  unsigned long tmp;
  FILE *fh = NULL;
  char *buf = malloc(100);

  if (argc > 1) {
    if (argv[1]) {
      fh = fopen(argv[1], "r");
      if (fh == NULL) {
        printf("Cannot open %s\n", argv[1]);
        return 1;
      }
    }
  } else
      fh = stdin;

  while ((len = getline(&buf, &size, fh)) > 0) {
    errno = 0;
    tmp = strtoul(buf, NULL, 0);
    if (errno) {
	perror("vseq");
	return 1;
    }
    itable[cnt++] = tmp;
    if (cnt >= 100000)
        break;
  }

  num = 0;
  usex = sin(pha);
  usey = cos(pha);
  printf("X,Y\n");
  while (num < cnt) {
    double x1, y1, z1;
    nth = itable[num];
    num++;
    x1 = (nth - n1th)  * SCALING;
    y1 = (n1th - n2th) * SCALING;
    z1 = (n2th - n3th) * SCALING;
    x = (x1*usey+z1*usex);
    y = y1 + (z1*usey-x1*usex) / 2;
    if (num > 4)
        printf("%lf,%lf\n", x, y);

    n3th=n2th; n2th=n1th; n1th=nth;
  }
  return 0;
}