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// Copyright (c) 2004, 2016, Oracle and/or its affiliates. All rights reserved.
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License, version 2.0, as
// published by the Free Software Foundation.
//
// This program is also distributed with certain software (including
// but not limited to OpenSSL) that is licensed under separate terms,
// as designated in a particular file or component or in included license
// documentation. The authors of MySQL hereby grant you an
// additional permission to link the program and your derivative works
// with the separately licensed software that they have included with
// MySQL.
//
// Without limiting anything contained in the foregoing, this file,
// which is part of MySQL Connector/NET, is also subject to the
// Universal FOSS Exception, version 1.0, a copy of which can be found at
// http://oss.oracle.com/licenses/universal-foss-exception.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU General Public License, version 2.0, for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
using System.Collections.Generic;
namespace MySql.Data.Common
{
internal class Cache<TKeyType, TValueType>
{
private readonly int _capacity;
private readonly Queue<TKeyType> _keyQ;
private readonly Dictionary<TKeyType, TValueType> _contents;
public Cache(int initialCapacity, int capacity)
{
this._capacity = capacity;
this._contents = new Dictionary<TKeyType, TValueType>(initialCapacity);
if (capacity > 0)
{
this._keyQ = new Queue<TKeyType>(initialCapacity);
}
}
public TValueType this[TKeyType key]
{
get
{
TValueType val;
if (this._contents.TryGetValue(key, out val))
{
return val;
}
else
{
return default(TValueType);
}
}
set { this.InternalAdd(key, value); }
}
public void Add(TKeyType key, TValueType value)
{
this.InternalAdd(key, value);
}
private void InternalAdd(TKeyType key, TValueType value)
{
if (!this._contents.ContainsKey(key))
{
if (this._capacity > 0)
{
this._keyQ.Enqueue(key);
if (this._keyQ.Count > this._capacity)
{
this._contents.Remove(this._keyQ.Dequeue());
}
}
}
this._contents[key] = value;
}
}
}