Circular buffer implementation

SystemExtensions.NetStandard/Collections/CircularBuffer.cs

@@ -0,0 +1,208 @@
+using System.Linq;
+using System.Threading;
+
+namespace System.Collections.Generic;
+public sealed class CircularBuffer<T> : IList<T>
+{
+    private readonly T[] buffer;
+    private int head;
+    private int tail;
+
+    public int Count { get; private set; }
+    public bool IsReadOnly { get; } = false;
+
+    public T this[int index]
+    {
+        get
+        {
+            if (index > this.Count)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+
+            return this.buffer[(this.head + index) % this.buffer.Length];
+        }
+        set
+        {
+            if (index > this.Count)
+            {
+                throw new ArgumentOutOfRangeException(nameof(index));
+            }
+
+            this.buffer[(this.head + index) % this.buffer.Length] = value;
+        }
+    }
+
+    public CircularBuffer(int capacity)
+    {
+        if (capacity < 1) throw new ArgumentException($"{nameof(capacity)} cannot be smaller than 1");
+
+        this.buffer = new T[capacity];
+        this.head = 0;
+        this.tail = 0;
+    }
+
+    public CircularBuffer(T[] buffer, int head, int tail)
+    {
+        if (buffer.Length == 0) throw new ArgumentException($"{nameof(buffer)} cannot be of length 0");
+
+        this.buffer = buffer;
+        this.head = head;
+        this.tail = tail;
+        this.Count = this.tail < this.head ?
+            this.tail + this.buffer.Length - this.head + 1 :
+            this.tail - this.head + 1;
+    }
+
+    public CircularBuffer(T[] buffer)
+    {
+        if (buffer.Length == 0) throw new ArgumentException($"{nameof(buffer)} cannot be of length 0");
+
+        this.buffer = buffer;
+        this.head = 0;
+        this.tail = this.buffer.Length - 1;
+        this.Count = this.buffer.Length;
+    }
+
+    public void Add(T item)
+    {
+        if (this.Count == this.buffer.Length)
+        {
+            this.buffer[this.tail] = item;
+            this.tail = (this.tail + 1) % this.buffer.Length;
+            this.head = (this.head + 1) % this.buffer.Length;
+        }
+        else
+        {
+            this.buffer[this.tail] = item;
+            this.tail = (this.tail + 1) % this.buffer.Length;
+            this.Count++;
+        }
+    }
+
+    public void Clear()
+    {
+        this.head = 0;
+        this.tail = 0;
+        this.Count = 0;
+    }
+
+    public void DeepClear()
+    {
+        this.Clear();
+        Array.Clear(this.buffer, 0, this.buffer.Length);
+    }
+
+    public bool Contains(T item)
+    {
+        var comparer = EqualityComparer<T>.Default;
+        foreach(var itItem in this)
+        {
+            if (comparer.Equals(itItem, item))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    public bool Remove(T item)
+    {
+        var index = this.head;
+        var comparer = EqualityComparer<T>.Default;
+        for (var i = 0; i < this.Count; i++)
+        {
+            if (comparer.Equals(this.buffer[index % this.buffer.Length], item))
+            {
+                int nextIndex;
+                for (var j = 0; j < this.Count - i - 1; j++)
+                {
+                    nextIndex = (index + 1) % this.buffer.Length;
+                    this.buffer[index] = this.buffer[nextIndex];
+                    index = nextIndex;
+                }
+
+                this.Count--;
+                this.tail = this.tail == 0 ? this.buffer.Length - 1 : this.tail - 1;
+                return true;
+            }
+
+            index = (index + 1) % this.buffer.Length;
+        }
+
+        return false;
+    }
+
+    public void CopyTo(T[] array, int arrayIndex)
+    {
+        foreach(var item in this)
+        {
+            array[arrayIndex++] = item;
+        }
+    }
+
+    public IEnumerator<T> GetEnumerator()
+    {
+        var index = this.head;
+        for (var i = 0; i < this.Count; i++)
+        {
+            yield return this.buffer[index];
+            index = (index + 1) % this.buffer.Length;
+        }
+    }
+
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+        return this.GetEnumerator();
+    }
+
+    public int IndexOf(T item)
+    {
+        var comparer = EqualityComparer<T>.Default;
+        for (var i = 0; i < this.Count; i++)
+        {
+            if (comparer.Equals(this[i], item))
+            {
+                return i;
+            }
+        }
+
+        return -1;
+    }
+
+    public void Insert(int index, T item)
+    {
+        if (index < 0 || index > this.Count) throw new ArgumentOutOfRangeException(nameof(index));
+        
+        if (this.Count == this.buffer.Length) throw new InvalidOperationException("Cannot insert into a full buffer.");
+
+        if (index == this.Count)
+        {
+            this.Add(item);
+            return;
+        }
+
+        for (var i = this.Count; i > index; i--)
+        {
+            this.buffer[(this.head + i) % this.buffer.Length] = this.buffer[(this.head + i - 1) % this.buffer.Length];
+        }
+
+        this.buffer[(this.head + index) % this.buffer.Length] = item;
+        this.tail = (this.tail + 1) % this.buffer.Length;
+        this.Count++;
+    }
+
+    public void RemoveAt(int index)
+    {
+        if (index < 0 || index >= this.Count) throw new ArgumentOutOfRangeException(nameof(index));
+
+        for (var i = index; i < this.Count - 1; i++)
+        {
+            this.buffer[(this.head + i) % this.buffer.Length] = this.buffer[(this.head + i + 1) % this.buffer.Length];
+        }
+
+        this.tail = (this.tail - 1 + this.buffer.Length) % this.buffer.Length;
+        this.Count--;
+    }
+}

SystemExtensions.NetStandard/SystemExtensions.NetStandard.csproj

@@ -7,7 +7,7 @@
     <PackageLicenseFile>LICENSE</PackageLicenseFile>
     <PackageRequireLicenseAcceptance>true</PackageRequireLicenseAcceptance>
     <RootNamespace>System</RootNamespace>
-    <Version>1.6.2</Version>
+    <Version>1.6.3</Version>
     <Authors>Alexandru Macocian</Authors>
     <RepositoryUrl>https://github.com/AlexMacocian/SystemExtensions</RepositoryUrl>
     <Description>Extensions for the System namespace</Description>