Param.NET - An Automated Command-line Parameter Parser

using System;
using System.Xml;
using System.Collections;
using System.Collections.Specialized;

namespace Params
{
	public class Helper
	{
		public static object GetValue(object o, string key, object defaultValue)
		{
			if(o is IDictionary)
			{
				IDictionary dict = o as IDictionary;

				if(dict.Contains(key))
					return dict[key];
				else
					return defaultValue;
			}
			if(o is NameValueCollection)
			{
				NameValueCollection nvc = o as NameValueCollection;

				if(nvc[key] != null)
					return nvc[key];
				else
					return defaultValue;
			}
			if(o is XmlAttributeCollection)
			{
				XmlAttributeCollection xac = o as XmlAttributeCollection;
				
				if(xac[key] != null)
					return xac[key].Value;
				else
					return defaultValue;
			}

			throw new InvalidOperationException();
		}

		public static bool GetBool(object o, string key, bool defaultValue)
		{
			object ret = GetValue(o, key, null);

			if(ret == null)
				return defaultValue;
			else
				return Convert.ToBoolean(ret);
		}

		public static int GetInt(object o, string key, int defaultValue)
		{
			object ret = GetValue(o, key, null);

			if(ret == null)
				return defaultValue;
			else
				return Convert.ToInt32(ret);
		}
		public static float GetFloat(object o, string key, float defaultValue)
		{
			object ret = GetValue(o, key, null);

			if(ret == null)
				return defaultValue;
			else
				return Convert.ToSingle(ret);
		}
		public static Enum GetEnum(object o, string key, Enum defaultValue, Type enumType)
		{
			object ret = GetValue(o, key, defaultValue);
			if(ret is string)
				return (Enum)Enum.Parse(enumType, (string)ret, true);
			else
				return (Enum)ret;
		}
		public static string GetString(object o, string key, string defaultValue)
		{
			return GetValue(o, key, defaultValue) as string;
		}

		public static int BeginsWith(string str, int offset, params string[] patterns)
		{
			for(int i = 0; i < patterns.Length; i++)
			{
				string pattern = patterns[i];
				if(	pattern != null && 
					pattern != string.Empty && 
					str.Length >= (pattern.Length + offset) &&
					str.Substring(offset, pattern.Length).Equals(pattern))
				{
					return i;
				}
			}
			return -1;
		}
	
		public static int GetNextParamIndex(string cmdLine, int offset, string shortControlString, string longControlString)
		{
			int valueEndIndexShort = cmdLine.IndexOf(shortControlString, offset);
			int valueEndIndexLong = cmdLine.IndexOf(longControlString, offset);

			if(valueEndIndexShort == -1 && valueEndIndexLong == -1)
				return cmdLine.Length-1;
			else if(valueEndIndexLong == -1)
				return valueEndIndexShort;
			else if(valueEndIndexShort == -1)
				return valueEndIndexLong;
			else
			{
				return Math.Min(valueEndIndexLong, valueEndIndexShort);
			}
		}
	}
}