/*
 *    The contents of this file are subject to the Initial
 *    Developer's Public License Version 1.0 (the "License");
 *    you may not use this file except in compliance with the
 *    License. You may obtain a copy of the License at
 *    https://github.com/FirebirdSQL/NETProvider/blob/master/license.txt.
 *
 *    Software distributed under the License is distributed on
 *    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either
 *    express or implied. See the License for the specific
 *    language governing rights and limitations under the License.
 *
 *    All Rights Reserved.
 */

//$Authors = Jiri Cincura (jiri@cincura.net)

using System;
using System.Collections.Generic;

namespace EntityFramework.Firebird.SqlGen
{
	internal sealed class SymbolTable
	{
		#region Fields

		private List<Dictionary<string, Symbol>> _symbols = new List<Dictionary<string, Symbol>>();

		#endregion

		#region Methods

		internal void EnterScope()
		{
			_symbols.Add(new Dictionary<string, Symbol>(StringComparer.OrdinalIgnoreCase));
		}

		internal void ExitScope()
		{
			_symbols.RemoveAt(_symbols.Count - 1);
		}

		internal void Add(string name, Symbol value)
		{
			_symbols[_symbols.Count - 1][name] = value;
		}

		internal Symbol Lookup(string name)
		{
			for (var i = _symbols.Count - 1; i >= 0; --i)
			{
				if (_symbols[i].ContainsKey(name))
				{
					return _symbols[i][name];
				}
			}

			return null;
		}

		#endregion
	}
}
