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76 lines
2.4 KiB
76 lines
2.4 KiB
// Copyright (c) 2004-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License version 2 as published by
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// the Free Software Foundation
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//
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// There are special exceptions to the terms and conditions of the GPL
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// as it is applied to this software. View the full text of the
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// exception in file EXCEPTIONS in the directory of this software
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// distribution.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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using System;
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using System.Collections.Generic;
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namespace MySql.Data.Common
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{
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internal class Cache<KeyType, ValueType>
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{
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private int _capacity;
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private Queue<KeyType> _keyQ;
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private Dictionary<KeyType, ValueType> _contents;
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public Cache(int initialCapacity, int capacity)
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{
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_capacity = capacity;
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_contents = new Dictionary<KeyType, ValueType>(initialCapacity);
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if (capacity > 0)
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_keyQ = new Queue<KeyType>(initialCapacity);
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}
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public ValueType this[KeyType key]
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{
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get
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{
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ValueType val;
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if (_contents.TryGetValue(key, out val))
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return val;
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else
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return default(ValueType);
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}
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set { InternalAdd(key, value); }
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}
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public void Add(KeyType key, ValueType value)
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{
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InternalAdd(key, value);
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}
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private void InternalAdd(KeyType key, ValueType value)
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{
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if (!_contents.ContainsKey(key))
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{
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if (_capacity > 0)
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{
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_keyQ.Enqueue(key);
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if (_keyQ.Count > _capacity)
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_contents.Remove(_keyQ.Dequeue());
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}
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}
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_contents[key] = value;
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}
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}
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}
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