C# php Serializer

C php Serializer.cs

	/// <summary>
	/// Serializer Class.
	/// </summary>
	public class Serializer
	{
		//types:
		// N = null
		// s = string
		// i = int
		// d = double
		// a = array (hashtable)

		private Dictionary<Hashtable, bool> seenHashtables; //for serialize (to infinte prevent loops)
		private Dictionary<ArrayList, bool> seenArrayLists; //for serialize (to infinte prevent loops) lol

		private int pos; //for unserialize

		public bool XMLSafe = true; //This member tells the serializer wether or not to strip carriage returns from strings when serializing and adding them back in when deserializing
		//http://www.w3.org/TR/REC-xml/#sec-line-ends

		public Encoding StringEncoding = new System.Text.UTF8Encoding();

		private System.Globalization.NumberFormatInfo nfi;

		public Serializer()
		{
			this.nfi = new System.Globalization.NumberFormatInfo();
			this.nfi.NumberGroupSeparator = "";
			this.nfi.NumberDecimalSeparator = ".";
		}

		public string Serialize(object obj)
		{
			this.seenArrayLists = new Dictionary<ArrayList, bool>();
			this.seenHashtables = new Dictionary<Hashtable, bool>();

			return this.serialize(obj, new StringBuilder()).ToString();
		}//Serialize(object obj)

		private StringBuilder serialize(object obj, StringBuilder sb)
		{
			if (obj == null)
			{
				return sb.Append("N;");
			}
			else if (obj is string)
			{
				string str = (string)obj;
				if (this.XMLSafe)
				{
					str = str.Replace("\r\n", "\n");//replace \r\n with \n
					str = str.Replace("\r", "\n");//replace \r not followed by \n with a single \n  Should we do this?
				}
				return sb.Append("s:" + this.StringEncoding.GetByteCount(str) + ":\"" + str + "\";");
			}
			else if (obj is bool)
			{
				return sb.Append("b:" + (((bool)obj) ? "1" : "0") + ";");
			}
			else if (obj is int)
			{
				int i = (int)obj;
				return sb.Append("i:" + i.ToString(this.nfi) + ";");
			}
			else if (obj is double)
			{
				double d = (double)obj;

				return sb.Append("d:" + d.ToString(this.nfi) + ";");
			}
			else if (obj is ArrayList)
			{
				if (this.seenArrayLists.ContainsKey((ArrayList)obj))
					return sb.Append("N;");//cycle detected
				else
					this.seenArrayLists.Add((ArrayList)obj, true);

				ArrayList a = (ArrayList)obj;
				sb.Append("a:" + a.Count + ":{");
				for (int i = 0; i < a.Count; i++)
				{
					this.serialize(i, sb);
					this.serialize(a[i], sb);
				}
				sb.Append("}");
				return sb;
			}
			else if (obj is Hashtable)
			{
				if (this.seenHashtables.ContainsKey((Hashtable)obj))
					return sb.Append("N;");//cycle detected
				else
					this.seenHashtables.Add((Hashtable)obj, true);

				Hashtable a = (Hashtable)obj;
				sb.Append("a:" + a.Count + ":{");
				foreach (DictionaryEntry entry in a)
				{
					this.serialize(entry.Key, sb);
					this.serialize(entry.Value, sb);
				}
				sb.Append("}");
				return sb;
			}
			else
			{
				return sb;
			}
		}//Serialize(object obj)

		public object Deserialize(string str)
		{
			this.pos = 0;
			return deserialize(str);
		}//Deserialize(string str)

		private object deserialize(string str)
		{
			if (str == null || str.Length <= this.pos)
				return new Object();

			int start, end, length;
			string stLen;
			switch (str[this.pos])
			{
				case 'N':
					this.pos += 2;
					return null;
				case 'b':
					char chBool;
					chBool = str[pos + 2];
					this.pos += 4;
					return chBool == '1';
				case 'i':
					string stInt;
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(";", start);
					stInt = str.Substring(start, end - start);
					this.pos += 3 + stInt.Length;
					return Int32.Parse(stInt, this.nfi);
				case 'd':
					string stDouble;
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(";", start);
					stDouble = str.Substring(start, end - start);
					this.pos += 3 + stDouble.Length;
					return Double.Parse(stDouble, this.nfi);
				case 's':
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(":", start);
					stLen = str.Substring(start, end - start);
					int bytelen = Int32.Parse(stLen);
					length = bytelen;
					//This is the byte length, not the character length - so we migth  
					//need to shorten it before usage. This also implies bounds checking
					if ((end + 2 + length) >= str.Length) length = str.Length - 2 - end;
					string stRet = str.Substring(end + 2, length);
					while (this.StringEncoding.GetByteCount(stRet) > bytelen)
					{
						length--;
						stRet = str.Substring(end + 2, length);
					}
					this.pos += 6 + stLen.Length + length;
					if (this.XMLSafe)
					{
						stRet = stRet.Replace("\n", "\r\n");
					}
					return stRet;
				case 'a':
					//if keys are ints 0 through N, returns an ArrayList, else returns Hashtable
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(":", start);
					stLen = str.Substring(start, end - start);
					length = Int32.Parse(stLen);
					Hashtable htRet = new Hashtable(length);
					ArrayList alRet = new ArrayList(length);
					this.pos += 4 + stLen.Length; //a:Len:{
					for (int i = 0; i < length; i++)
					{
						//read key
						object key = deserialize(str);
						//read value
						object val = deserialize(str);

						if (alRet != null)
						{
							if (key is int && (int)key == alRet.Count)
								alRet.Add(val);
							else
								alRet = null;
						}
						htRet[key] = val;
					}
					this.pos++; //skip the }
					if (this.pos < str.Length && str[this.pos] == ';')//skipping our old extra array semi-colon bug (er... php's weirdness)
						this.pos++;
					if (alRet != null)
						return alRet;
					else
						return htRet;
				default:
					return "";
			}//switch
		}//unserialzie(object)	
	}//class Serializer

C# php Serializer.cs

	/// <summary>
	/// Serializer Class.
	/// </summary>
	public class Serializer
	{
		//types:
		// N = null
		// s = string
		// i = int
		// d = double
		// a = array (hashtable)

		private Dictionary<Hashtable, bool> seenHashtables; //for serialize (to infinte prevent loops)
		private Dictionary<ArrayList, bool> seenArrayLists; //for serialize (to infinte prevent loops) lol

		private int pos; //for unserialize

		public bool XMLSafe = true; //This member tells the serializer wether or not to strip carriage returns from strings when serializing and adding them back in when deserializing
		//http://www.w3.org/TR/REC-xml/#sec-line-ends

		public Encoding StringEncoding = new System.Text.UTF8Encoding();

		private System.Globalization.NumberFormatInfo nfi;

		public Serializer()
		{
			this.nfi = new System.Globalization.NumberFormatInfo();
			this.nfi.NumberGroupSeparator = "";
			this.nfi.NumberDecimalSeparator = ".";
		}

		public string Serialize(object obj)
		{
			this.seenArrayLists = new Dictionary<ArrayList, bool>();
			this.seenHashtables = new Dictionary<Hashtable, bool>();

			return this.serialize(obj, new StringBuilder()).ToString();
		}//Serialize(object obj)

		private StringBuilder serialize(object obj, StringBuilder sb)
		{
			if (obj == null)
			{
				return sb.Append("N;");
			}
			else if (obj is string)
			{
				string str = (string)obj;
				if (this.XMLSafe)
				{
					str = str.Replace("\r\n", "\n");//replace \r\n with \n
					str = str.Replace("\r", "\n");//replace \r not followed by \n with a single \n  Should we do this?
				}
				return sb.Append("s:" + this.StringEncoding.GetByteCount(str) + ":\"" + str + "\";");
			}
			else if (obj is bool)
			{
				return sb.Append("b:" + (((bool)obj) ? "1" : "0") + ";");
			}
			else if (obj is int)
			{
				int i = (int)obj;
				return sb.Append("i:" + i.ToString(this.nfi) + ";");
			}
			else if (obj is double)
			{
				double d = (double)obj;

				return sb.Append("d:" + d.ToString(this.nfi) + ";");
			}
			else if (obj is ArrayList)
			{
				if (this.seenArrayLists.ContainsKey((ArrayList)obj))
					return sb.Append("N;");//cycle detected
				else
					this.seenArrayLists.Add((ArrayList)obj, true);

				ArrayList a = (ArrayList)obj;
				sb.Append("a:" + a.Count + ":{");
				for (int i = 0; i < a.Count; i++)
				{
					this.serialize(i, sb);
					this.serialize(a[i], sb);
				}
				sb.Append("}");
				return sb;
			}
			else if (obj is Hashtable)
			{
				if (this.seenHashtables.ContainsKey((Hashtable)obj))
					return sb.Append("N;");//cycle detected
				else
					this.seenHashtables.Add((Hashtable)obj, true);

				Hashtable a = (Hashtable)obj;
				sb.Append("a:" + a.Count + ":{");
				foreach (DictionaryEntry entry in a)
				{
					this.serialize(entry.Key, sb);
					this.serialize(entry.Value, sb);
				}
				sb.Append("}");
				return sb;
			}
			else
			{
				return sb;
			}
		}//Serialize(object obj)

		public object Deserialize(string str)
		{
			this.pos = 0;
			return deserialize(str);
		}//Deserialize(string str)

		private object deserialize(string str)
		{
			if (str == null || str.Length <= this.pos)
				return new Object();

			int start, end, length;
			string stLen;
			switch (str[this.pos])
			{
				case 'N':
					this.pos += 2;
					return null;
				case 'b':
					char chBool;
					chBool = str[pos + 2];
					this.pos += 4;
					return chBool == '1';
				case 'i':
					string stInt;
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(";", start);
					stInt = str.Substring(start, end - start);
					this.pos += 3 + stInt.Length;
					return Int32.Parse(stInt, this.nfi);
				case 'd':
					string stDouble;
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(";", start);
					stDouble = str.Substring(start, end - start);
					this.pos += 3 + stDouble.Length;
					return Double.Parse(stDouble, this.nfi);
				case 's':
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(":", start);
					stLen = str.Substring(start, end - start);
					int bytelen = Int32.Parse(stLen);
					length = bytelen;
					//This is the byte length, not the character length - so we migth  
					//need to shorten it before usage. This also implies bounds checking
					if ((end + 2 + length) >= str.Length) length = str.Length - 2 - end;
					string stRet = str.Substring(end + 2, length);
					while (this.StringEncoding.GetByteCount(stRet) > bytelen)
					{
						length--;
						stRet = str.Substring(end + 2, length);
					}
					this.pos += 6 + stLen.Length + length;
					if (this.XMLSafe)
					{
						stRet = stRet.Replace("\n", "\r\n");
					}
					return stRet;
				case 'a':
					//if keys are ints 0 through N, returns an ArrayList, else returns Hashtable
					start = str.IndexOf(":", this.pos) + 1;
					end = str.IndexOf(":", start);
					stLen = str.Substring(start, end - start);
					length = Int32.Parse(stLen);
					Hashtable htRet = new Hashtable(length);
					ArrayList alRet = new ArrayList(length);
					this.pos += 4 + stLen.Length; //a:Len:{
					for (int i = 0; i < length; i++)
					{
						//read key
						object key = deserialize(str);
						//read value
						object val = deserialize(str);

						if (alRet != null)
						{
							if (key is int && (int)key == alRet.Count)
								alRet.Add(val);
							else
								alRet = null;
						}
						htRet[key] = val;
					}
					this.pos++; //skip the }
					if (this.pos < str.Length && str[this.pos] == ';')//skipping our old extra array semi-colon bug (er... php's weirdness)
						this.pos++;
					if (alRet != null)
						return alRet;
					else
						return htRet;
				default:
					return "";
			}//switch
		}//unserialzie(object)	
	}//class Serializer

FYI, I wrote my own PHP de/serialization library because I ran into some limitations of this one (both in terms of functionality and license).

https://github.com/StringEpsilon/PhpSerializerNET

Update: It has full support for the object notation now.