Question

I am trying to create my own Circular Buffer in C#. I am using a counter to keep track of where I need to insert the next item. Here is a Link to the full code and here is the (simplified) code to do so:

public class CircularBuffer<T>
{
    private bool _isFull = false;

    private int _size;
    private int _current = 0;

    private BufferItem<T>[] _buffer;

    public CircularBuffer(int size)
    {
        _size = size;
        _buffer = new BufferItem<T>[size];
    }

    public void Insert(T value)
    {
        BufferItem<T> item = new BufferItem<T>(value);
        //Removed code to check if the buffer is full, if so over-write the oldest item
        //and don't insert at the current position
        _buffer[_current] = item;
        _isFull = (_current == (_size - 1));
        _current++;

        //Age all items            
    }

It all works fine and dandy until after I increment the current position and try to add another item:

Here I added the item "first" and the current position (_current) is incremented.

I added the item "third" but the current position gets reset to 0. There is absolutely no other code including _current other than declaring it, accessing it and incrementing it.
What in the world is going on? Here is the code for BufferItem<T>:

public class BufferItem<T>
{
    public int Age = 0;
    public T Item;

    public BufferItem(T item)
    {
        Item = item;
    }
}

Answer 1

Your class methods are fine. Your _current variable works fine, too. The issue lies outside of the CircularBuffer class. Somewhere where this is being implemented, the CircularBuffer object in question is getting reset in some way.