Create a Circular Queue

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In this challenge you will be creating a Circular Queue. A circular queue is a queue that writes to the end of a collection then begins overwriting itself at the beginning of the collection. This type of data structure is useful in certain situations. For example, a circular queue can be used for streaming media. Once the queue is full, new media data will overwrite old data.

A good way to illustrate this concept is with an array of length 5:

[null, null, null, null, null]
 ^Read @ 0
 ^Write @ 0

Here the read and write are both at position 0. Now the queue gets 3 new records a, b, and c. Our queue now looks like:

[a, b, c, null, null]
 ^Read @ 0
          ^Write @ 3

As the read head reads, it can remove values or keep them:

[null, null, null, null, null]
                   ^Read @ 3
                   ^Write @ 3

Now we write the values d, e, and f to the queue. Once the write reaches the end of the array it loops back to the beginning:

[f, null, null, d, e]
                ^Read @ 3
    ^Write @ 1

This approach requires a constant amount of memory but allows files of a much larger size to be processed.