1 files changed, 178 insertions, 0 deletions
diff --git a/crypto/src/util/collections/LinkedDictionary.cs b/crypto/src/util/collections/LinkedDictionary.cs
new file mode 100644
index 000000000..933d38ded
--- /dev/null
+++ b/crypto/src/util/collections/LinkedDictionary.cs
@@ -0,0 +1,178 @@
+using System;
+using System.Collections;
+
+namespace Org.BouncyCastle.Utilities.Collections
+{
+	public class LinkedDictionary
+		: IDictionary
+	{
+		internal readonly IDictionary hash = Platform.CreateHashtable();
+		internal readonly IList keys = Platform.CreateArrayList();
+
+		public LinkedDictionary()
+		{
+		}
+
+		public virtual void Add(object k, object v)
+		{
+			hash.Add(k, v);
+			keys.Add(k);
+		}
+
+		public virtual void Clear()
+		{
+			hash.Clear();
+			keys.Clear();
+		}
+
+		public virtual bool Contains(object k)
+		{
+			return hash.Contains(k);
+		}
+
+		public virtual void CopyTo(Array array, int index)
+		{
+			foreach (object k in keys)
+			{
+				array.SetValue(hash[k], index++);
+			}
+		}
+
+		public virtual int Count
+		{
+			get { return hash.Count; }
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		public virtual IDictionaryEnumerator GetEnumerator()
+		{
+			return new LinkedDictionaryEnumerator(this);
+		}
+
+		public virtual void Remove(object k)
+		{
+			hash.Remove(k);
+			keys.Remove(k);
+		}
+
+		public virtual bool IsFixedSize
+		{
+			get { return false; }
+		}
+
+		public virtual bool IsReadOnly
+		{
+			get { return false; }
+		}
+
+		public virtual bool IsSynchronized
+		{
+			get { return false; }
+		}
+
+		public virtual object SyncRoot
+		{
+			get { return false; }
+		}
+
+		public virtual ICollection Keys
+		{
+            get { return Platform.CreateArrayList(keys); }
+		}
+
+		public virtual ICollection Values
+		{
+			// NB: Order has to be the same as for Keys property
+			get
+			{
+                IList values = Platform.CreateArrayList(keys.Count);
+				foreach (object k in keys)
+				{
+					values.Add(hash[k]);
+				}
+				return values;
+			}
+		}
+
+		public virtual object this[object k]
+		{
+			get
+			{
+				return hash[k];
+			}
+			set
+			{
+				if (!hash.Contains(k))
+					keys.Add(k);
+				hash[k] = value;
+			}
+		}
+	}
+
+	internal class LinkedDictionaryEnumerator : IDictionaryEnumerator
+	{
+		private readonly LinkedDictionary parent;
+		private int pos = -1;
+
+		internal LinkedDictionaryEnumerator(LinkedDictionary parent)
+		{
+			this.parent = parent;
+		}
+
+		public virtual object Current
+		{
+			get { return Entry; }
+		}
+
+		public virtual DictionaryEntry Entry
+		{
+			get
+			{
+				object k = CurrentKey;
+				return new DictionaryEntry(k, parent.hash[k]);
+			}
+		}
+
+		public virtual object Key
+		{
+			get
+			{
+				return CurrentKey;
+			}
+		}
+
+		public virtual bool MoveNext()
+		{
+			if (pos >= parent.keys.Count)
+				return false;
+			return ++pos < parent.keys.Count;
+		}
+
+		public virtual void Reset()
+		{
+			this.pos = -1;
+		}
+
+		public virtual object Value
+		{
+			get
+			{
+				return parent.hash[CurrentKey];
+			}
+		}
+
+		private object CurrentKey
+		{
+			get
+			{
+				if (pos < 0 || pos >= parent.keys.Count)
+					throw new InvalidOperationException();
+				return parent.keys[pos];
+			}
+		}
+	}
+}