// The MIT License (MIT)

//

// Copyright (c) 2015-2020 Rasmus Mikkelsen

// Copyright (c) 2015-2020 eBay Software Foundation

// https://github.com/eventflow/EventFlow

//

// Permission is hereby granted, free of charge, to any person obtaining a copy of

// this software and associated documentation files (the "Software"), to deal in

// the Software without restriction, including without limitation the rights to

// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of

// the Software, and to permit persons to whom the Software is furnished to do so,

// subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS

// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR

// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER

// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

using System;

using System.Collections;

using System.Collections.Generic;

namespace EventFlow.Core

{

public class CircularBuffer<T> : IEnumerable<T>

{

private readonly T[] _buffer;

private int _start;

private int _end;

public int Capacity => _buffer.Length - 1;

public CircularBuffer(int capacity)

{

if (capacity <= 0) throw new ArgumentException(nameof(capacity));

_buffer = new T[capacity + 1];

_start = 0;

_end = 0;

}

public CircularBuffer(int capacity, params T[] items)

: this(capacity)

{

if (items.Length > capacity) throw new ArgumentException(nameof(capacity));

foreach (var item in items)

{

Put(item);

}

}

public void Put(T item)

{

_buffer[_end] = item;

_end = (_end + 1) % _buffer.Length;

if (_end == _start)

{

_start = (_start + 1) % _buffer.Length;

}

}

public IEnumerator<T> GetEnumerator()

{

var i = _start;

while (i != _end)

{

yield return _buffer[i];

i = (i + 1) % _buffer.Length;

}

}

IEnumerator IEnumerable.GetEnumerator()

{

return GetEnumerator();

}

}

}