The “beck” exploit. A popular web server supports a function named no2slash() whose purpos...

The “beck” exploit. A popular web server supports a function named no2slash() whose purpose is to collapse multiple / characters. For example, the string /d1///d2////d3/test.html collapses to /d1/d2/d3/test.html. The original algorithm was to repeatedly search for a / and copy the remainder of the string:

int n = name.length();int i = 1;while (i < n){  if ((c[i-1] == '/') && (c[i] == '/'))  {   for(int j = i+1; j < n; j++)     c[j-1] = c[j];    n--;  }  else i++;}

Unfortunately, this code can takes quadratic time (for example, if the string consists of the / character repeated n times). By sending multiple simultaneous requests with large numbers of / characters, a hacker could deluge the server and starve other processes for CPU time, thereby creating a denial-of-service attack. Develop a version of no2slash() that runs in linear time and does not allow for this type of attack.