www.pudn.com > IntroductionTo3DGameEngineDesign.rar > Logic.cs

using System; 
using System.Xml; 
using System.Diagnostics; 
 
namespace GameAI 
{ 
	/// 
 
	/// Summary description for Logic. 
	/// 
 
	public class Logic 
	{ 
		#region Attributes 
		private Fact m_first; 
		private Fact m_second; 
		private Operator m_operator; 
		#endregion 
 
		#region Properties 
		public Fact FirstFact { get { return m_first; } set { m_first = value; } } 
		public Fact SecondFact { get { return m_second; } set { m_second = value; } } 
		public Operator Operation { get { return m_operator; } set { m_operator = value; } } 
		#endregion 
 
		public Logic() 
		{ 
			m_first = null; 
			m_second = null; 
			m_operator = Operator.Equals; 
		} 
 
		public Logic(Fact first, Fact second, Operator op) 
		{ 
			m_first = first; 
			m_second = second; 
			m_operator = op; 
		} 
 
		public bool Evaluate() 
		{ 
			bool result = false; 
 
			if ( m_first != null ) 
			{ 
				switch ( m_operator ) 
				{ 
					case Operator.And: 
						if ( m_second != null ) 
						{ 
							result = m_first.IsTrue && m_second.IsTrue; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.Equals: 
						if ( m_second != null ) 
						{ 
							result = m_first.Value == m_second.Value; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.GreaterThan: 
						if ( m_second != null ) 
						{ 
							result = m_first.Value > m_second.Value; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.GreaterThanEquals: 
						if ( m_second != null ) 
						{ 
							result = m_first.Value >= m_second.Value; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.LessThan: 
						if ( m_second != null ) 
						{ 
							result = m_first.Value < m_second.Value; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.LessThanEquals: 
						if ( m_second != null ) 
						{ 
							result = m_first.Value <= m_second.Value; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.NotEqual: 
						if ( m_second != null ) 
						{ 
							result = m_first.Value != m_second.Value; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.Or: 
						if ( m_second != null ) 
						{ 
							result = m_first.IsTrue || m_second.IsTrue; 
						} 
						else 
						{ 
							Debug.WriteLine("second fact missing in Logic"); 
						} 
						break; 
					case Operator.True: 
						result = m_first.IsTrue; 
						break; 
					case Operator.False: 
						result = !m_first.IsTrue; 
						break; 
				} 
			} 
			else 
			{ 
				Debug.WriteLine("first fact missing in Logic"); 
			} 
 
			return result; 
		} 
 
		public void Write( XmlTextWriter writer ) 
		{ 
			writer.WriteStartElement("Logic"); 
			writer.WriteElementString("Fact1", m_first.Name); 
			writer.WriteElementString("Operator", m_operator.ToString()); 
			writer.WriteElementString("Fact2", m_second.Name); 
			writer.WriteEndElement(); 
		} 
 
		public void Read ( XmlTextReader reader, Thinker thinker ) 
		{ 
			bool done = false; 
 
			while ( !done )  
			{ 
				reader.Read(); 
 
				if ( reader.NodeType == XmlNodeType.EndElement && 
					reader.Name == "Logic" ) 
				{ 
					done =true; 
				} 
					// Process a start of element node. 
				else if (reader.NodeType == XmlNodeType.Element)  
				{  
					// Process a text node. 
					if ( reader.Name == "Fact1" )  
					{ 
						while (reader.NodeType != XmlNodeType.Text)  
						{ 
							reader.Read(); 
						} 
						m_first = thinker.GetFact(reader.Value); 
					} 
					if ( reader.Name == "Fact2" )  
					{ 
						while (reader.NodeType != XmlNodeType.Text)  
						{ 
							reader.Read(); 
						} 
						m_second = thinker.GetFact(reader.Value); 
					} 
					if ( reader.Name == "Operator" )  
					{ 
						while (reader.NodeType != XmlNodeType.Text)  
						{ 
							reader.Read(); 
						} 
						switch ( reader.Value ) 
						{ 
							case "And": 
								m_operator = Operator.And; 
								break; 
							case "Equals": 
								m_operator = Operator.Equals; 
								break; 
							case "GreaterThan": 
								m_operator = Operator.GreaterThan; 
								break; 
							case "GreaterThanEquals": 
								m_operator = Operator.GreaterThanEquals; 
								break; 
							case "LessThan": 
								m_operator = Operator.LessThan; 
								break; 
							case "LessThanEquals": 
								m_operator = Operator.LessThanEquals; 
								break; 
							case "NotEqual": 
								m_operator = Operator.NotEqual; 
								break; 
							case "Or": 
								m_operator = Operator.Or; 
								break; 
							case "True": 
								m_operator = Operator.True; 
								break; 
							case "False": 
								m_operator = Operator.False; 
								break; 
						} 
					} 
				} 
			}// End while loop 
		} 
	} 
}