title: Memory efficient way to iterate on a big range
body: <p>I want to compare two really big data sets byte-by-byte in a specific range.</p>
  
  <p>So for example I'd have one 0x80000000 bytes long file and another 0xffffffff bytes long file.
  And lets say I'd like to compare these two files in a specific range byte-by-byte from 0x1000 to 0x7200000.</p>
  
  <p>If it was a smaller range I'd probably go for <code>until</code>, but now since it's a much bigger range <code>until</code> would be pretty inefficient memory wise.</p>
  
  <p>How would one implement such basic operation in a functional and memory efficient way?</p>