using System;
using System.Collections;
using System.Globalization;
using System.Text;

using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Utilities.Encoders;

namespace Org.BouncyCastle.Asn1.X509
{
    /**
    * <pre>
    *     RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
    *
    *     RelativeDistinguishedName ::= SET SIZE (1..MAX) OF AttributeTypeAndValue
    *
    *     AttributeTypeAndValue ::= SEQUENCE {
    *                                   type  OBJECT IDENTIFIER,
    *                                   value ANY }
    * </pre>
    */
    public class X509Name
        : Asn1Encodable
    {
        /**
        * country code - StringType(SIZE(2))
        */
        public static readonly DerObjectIdentifier C = new DerObjectIdentifier("2.5.4.6");

        /**
        * organization - StringType(SIZE(1..64))
        */
        public static readonly DerObjectIdentifier O = new DerObjectIdentifier("2.5.4.10");

        /**
        * organizational unit name - StringType(SIZE(1..64))
        */
        public static readonly DerObjectIdentifier OU = new DerObjectIdentifier("2.5.4.11");

        /**
        * Title
        */
        public static readonly DerObjectIdentifier T = new DerObjectIdentifier("2.5.4.12");

        /**
        * common name - StringType(SIZE(1..64))
        */
        public static readonly DerObjectIdentifier CN = new DerObjectIdentifier("2.5.4.3");

		/**
		* street - StringType(SIZE(1..64))
		*/
		public static readonly DerObjectIdentifier Street = new DerObjectIdentifier("2.5.4.9");

		/**
		* device serial number name - StringType(SIZE(1..64))
		*/
		public static readonly DerObjectIdentifier SerialNumber = new DerObjectIdentifier("2.5.4.5");

		/**
        * locality name - StringType(SIZE(1..64))
        */
        public static readonly DerObjectIdentifier L = new DerObjectIdentifier("2.5.4.7");

        /**
        * state, or province name - StringType(SIZE(1..64))
        */
        public static readonly DerObjectIdentifier ST = new DerObjectIdentifier("2.5.4.8");

        /**
        * Naming attributes of type X520name
        */
        public static readonly DerObjectIdentifier Surname = new DerObjectIdentifier("2.5.4.4");
        public static readonly DerObjectIdentifier GivenName = new DerObjectIdentifier("2.5.4.42");
        public static readonly DerObjectIdentifier Initials = new DerObjectIdentifier("2.5.4.43");
        public static readonly DerObjectIdentifier Generation = new DerObjectIdentifier("2.5.4.44");
        public static readonly DerObjectIdentifier UniqueIdentifier = new DerObjectIdentifier("2.5.4.45");

		/**
		 * businessCategory - DirectoryString(SIZE(1..128)
		 */
		public static readonly DerObjectIdentifier BusinessCategory = new DerObjectIdentifier(
																	   "2.5.4.15");

		/**
		 * postalCode - DirectoryString(SIZE(1..40)
		 */
		public static readonly DerObjectIdentifier PostalCode = new DerObjectIdentifier(
																 "2.5.4.17");

		/**
		 * dnQualifier - DirectoryString(SIZE(1..64)
		 */
		public static readonly DerObjectIdentifier DnQualifier = new DerObjectIdentifier(
														 "2.5.4.46");

		/**
		 * RFC 3039 Pseudonym - DirectoryString(SIZE(1..64)
		 */
		public static readonly DerObjectIdentifier Pseudonym = new DerObjectIdentifier(
																"2.5.4.65");

		/**
		 * RFC 3039 DateOfBirth - GeneralizedTime - YYYYMMDD000000Z
		 */
		public static readonly DerObjectIdentifier DateOfBirth = new DerObjectIdentifier(
																  "1.3.6.1.5.5.7.9.1");

		/**
		 * RFC 3039 PlaceOfBirth - DirectoryString(SIZE(1..128)
		 */
		public static readonly DerObjectIdentifier PlaceOfBirth = new DerObjectIdentifier(
																   "1.3.6.1.5.5.7.9.2");

		/**
		 * RFC 3039 DateOfBirth - PrintableString (SIZE(1)) -- "M", "F", "m" or "f"
		 */
		public static readonly DerObjectIdentifier Gender = new DerObjectIdentifier(
																   "1.3.6.1.5.5.7.9.3");

		/**
		 * RFC 3039 CountryOfCitizenship - PrintableString (SIZE (2)) -- ISO 3166
		 * codes only
		 */
		public static readonly DerObjectIdentifier CountryOfCitizenship = new DerObjectIdentifier(
																		   "1.3.6.1.5.5.7.9.4");

		/**
		 * RFC 3039 CountryOfCitizenship - PrintableString (SIZE (2)) -- ISO 3166
		 * codes only
		 */
		public static readonly DerObjectIdentifier CountryOfResidence = new DerObjectIdentifier(
																		 "1.3.6.1.5.5.7.9.5");

		/**
		 * ISIS-MTT NameAtBirth - DirectoryString(SIZE(1..64)
		 */
		public static readonly DerObjectIdentifier NameAtBirth =  new DerObjectIdentifier("1.3.36.8.3.14");

		/**
		 * RFC 3039 PostalAddress - SEQUENCE SIZE (1..6) OF
		 * DirectoryString(SIZE(1..30))
		 */
		public static readonly DerObjectIdentifier PostalAddress = new DerObjectIdentifier(
																	"2.5.4.16");

		/**
        * Email address (RSA PKCS#9 extension) - IA5String.
        * <p>Note: if you're trying to be ultra orthodox, don't use this! It shouldn't be in here.</p>
        */
        public static readonly DerObjectIdentifier EmailAddress = PkcsObjectIdentifiers.Pkcs9AtEmailAddress;

        /**
        * more from PKCS#9
        */
        public static readonly DerObjectIdentifier UnstructuredName = PkcsObjectIdentifiers.Pkcs9AtUnstructuredName;
        public static readonly DerObjectIdentifier UnstructuredAddress = PkcsObjectIdentifiers.Pkcs9AtUnstructuredAddress;

        /**
        * email address in Verisign certificates
        */
        public static readonly DerObjectIdentifier E = EmailAddress;

        /*
        * others...
        */
        public static readonly DerObjectIdentifier DC = new DerObjectIdentifier("0.9.2342.19200300.100.1.25");

        /**
        * LDAP User id.
        */
        public static readonly DerObjectIdentifier UID = new DerObjectIdentifier("0.9.2342.19200300.100.1.1");

        /**
        * look up table translating OID values into their common symbols - this static is scheduled for deletion
        */
        public static Hashtable OIDLookup = new Hashtable();

        /**
        * determines whether or not strings should be processed and printed
        * from back to front.
        */
        public static bool DefaultReverse = false;

        /**
        * default look up table translating OID values into their common symbols following
        * the convention in RFC 2253 with a few extras
        */
        public static Hashtable DefaultSymbols = OIDLookup;

		/**
		 * look up table translating OID values into their common symbols following the convention in RFC 2253
		 */
		public static Hashtable RFC2253Symbols = new Hashtable();

		/**
		 * look up table translating OID values into their common symbols following the convention in RFC 1779
		 *
		 */
		public static Hashtable RFC1779Symbols = new Hashtable();

		/**
        * look up table translating string values into their OIDS -
        * this static is scheduled for deletion
        */
        public static Hashtable SymbolLookup = new Hashtable();

        /**
        * look up table translating common symbols into their OIDS.
        */
        public static Hashtable DefaultLookup = SymbolLookup;

        static X509Name()
        {
            DefaultSymbols.Add(C, "C");
            DefaultSymbols.Add(O, "O");
            DefaultSymbols.Add(T, "T");
            DefaultSymbols.Add(OU, "OU");
            DefaultSymbols.Add(CN, "CN");
            DefaultSymbols.Add(L, "L");
            DefaultSymbols.Add(ST, "ST");
            DefaultSymbols.Add(SerialNumber, "SERIALNUMBER");
            DefaultSymbols.Add(EmailAddress, "E");
            DefaultSymbols.Add(DC, "DC");
            DefaultSymbols.Add(UID, "UID");
			DefaultSymbols.Add(Street, "STREET");
            DefaultSymbols.Add(Surname, "SURNAME");
            DefaultSymbols.Add(GivenName, "GIVENNAME");
            DefaultSymbols.Add(Initials, "INITIALS");
            DefaultSymbols.Add(Generation, "GENERATION");
            DefaultSymbols.Add(UnstructuredAddress, "unstructuredAddress");
            DefaultSymbols.Add(UnstructuredName, "unstructuredName");
			DefaultSymbols.Add(UniqueIdentifier, "UniqueIdentifier");
			DefaultSymbols.Add(DnQualifier, "DN");
			DefaultSymbols.Add(Pseudonym, "Pseudonym");
			DefaultSymbols.Add(PostalAddress, "PostalAddress");
			DefaultSymbols.Add(NameAtBirth, "NameAtBirth");
			DefaultSymbols.Add(CountryOfCitizenship, "CountryOfCitizenship");
			DefaultSymbols.Add(CountryOfResidence, "CountryOfResidence");
			DefaultSymbols.Add(Gender, "Gender");
			DefaultSymbols.Add(PlaceOfBirth, "PlaceOfBirth");
			DefaultSymbols.Add(DateOfBirth, "DateOfBirth");
			DefaultSymbols.Add(PostalCode, "PostalCode");
			DefaultSymbols.Add(BusinessCategory, "BusinessCategory");

            RFC2253Symbols.Add(C, "C");
            RFC2253Symbols.Add(O, "O");
            RFC2253Symbols.Add(OU, "OU");
            RFC2253Symbols.Add(CN, "CN");
            RFC2253Symbols.Add(L, "L");
            RFC2253Symbols.Add(ST, "ST");
			RFC2253Symbols.Add(Street, "STREET");
			RFC2253Symbols.Add(DC, "DC");
            RFC2253Symbols.Add(UID, "UID");

			RFC1779Symbols.Add(C, "C");
			RFC1779Symbols.Add(O, "O");
			RFC1779Symbols.Add(OU, "OU");
			RFC1779Symbols.Add(CN, "CN");
			RFC1779Symbols.Add(L, "L");
			RFC1779Symbols.Add(ST, "ST");
			RFC1779Symbols.Add(Street, "STREET");

			DefaultLookup.Add("c", C);
            DefaultLookup.Add("o", O);
            DefaultLookup.Add("t", T);
            DefaultLookup.Add("ou", OU);
            DefaultLookup.Add("cn", CN);
            DefaultLookup.Add("l", L);
            DefaultLookup.Add("st", ST);
			DefaultLookup.Add("serialnumber", SerialNumber);
			DefaultLookup.Add("street", Street);
			DefaultLookup.Add("emailaddress", E);
            DefaultLookup.Add("dc", DC);
            DefaultLookup.Add("e", E);
            DefaultLookup.Add("uid", UID);
            DefaultLookup.Add("surname", Surname);
            DefaultLookup.Add("givenname", GivenName);
            DefaultLookup.Add("initials", Initials);
            DefaultLookup.Add("generation", Generation);
            DefaultLookup.Add("unstructuredaddress", UnstructuredAddress);
            DefaultLookup.Add("unstructuredname", UnstructuredName);
			DefaultLookup.Add("uniqueidentifier", UniqueIdentifier);
			DefaultLookup.Add("dn", DnQualifier);
			DefaultLookup.Add("pseudonym", Pseudonym);
			DefaultLookup.Add("postaladdress", PostalAddress);
			DefaultLookup.Add("nameofbirth", NameAtBirth);
			DefaultLookup.Add("countryofcitizenship", CountryOfCitizenship);
			DefaultLookup.Add("countryofresidence", CountryOfResidence);
			DefaultLookup.Add("gender", Gender);
			DefaultLookup.Add("placeofbirth", PlaceOfBirth);
			DefaultLookup.Add("dateofbirth", DateOfBirth);
			DefaultLookup.Add("postalcode", PostalCode);
			DefaultLookup.Add("businesscategory", BusinessCategory);
		}

		private readonly ArrayList ordering = new ArrayList();
		private readonly X509NameEntryConverter converter;

		private ArrayList		values = new ArrayList();
        private ArrayList		added = new ArrayList();
        private Asn1Sequence	seq;

		/**
        * Return a X509Name based on the passed in tagged object.
        *
        * @param obj tag object holding name.
        * @param explicitly true if explicitly tagged false otherwise.
        * @return the X509Name
        */
        public static X509Name GetInstance(
            Asn1TaggedObject	obj,
            bool				explicitly)
        {
            return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
        }

		public static X509Name GetInstance(
            object obj)
        {
            if (obj == null || obj is X509Name)
            {
                return (X509Name) obj;
            }

			if (obj is Asn1Sequence)
            {
                return new X509Name((Asn1Sequence) obj);
            }

			throw new ArgumentException("unknown object in factory: " + obj.GetType().Name);
        }

		/**
        * Constructor from Asn1Sequence
        *
        * the principal will be a list of constructed sets, each containing an (OID, string) pair.
        */
        protected X509Name(
            Asn1Sequence seq)
        {
            this.seq = seq;

			foreach (Asn1Set asn1Set in seq)
			{
				for (int i = 0; i < asn1Set.Count; i++)
                {
					Asn1Sequence s = Asn1Sequence.GetInstance(asn1Set[i]);

					if (s.Count != 2)
					{
						throw new ArgumentException("badly sized pair");
					}

					ordering.Add(DerObjectIdentifier.GetInstance(s[0]));

					IAsn1Convertible derValue = s[1];
                    if (derValue is IAsn1String)
                    {
                        values.Add(((IAsn1String) derValue).GetString());
                    }
                    else
                    {
						byte[] hex = Hex.Encode(derValue.ToAsn1Object().GetEncoded());
						values.Add("#" + Encoding.ASCII.GetString(hex, 0, hex.Length));
                    }

					added.Add(i != 0);
                }
            }
        }

		/**
        * Constructor from a table of attributes with ordering.
        * <p>
        * it's is assumed the table contains OID/string pairs, and the contents
        * of the table are copied into an internal table as part of the
        * construction process. The ordering ArrayList should contain the OIDs
        * in the order they are meant to be encoded or printed in ToString.</p>
        */
        public X509Name(
            ArrayList	ordering,
            Hashtable	attributes)
            : this(ordering, attributes, new X509DefaultEntryConverter())
        {
        }

		/**
        * Constructor from a table of attributes with ordering.
        * <p>
        * it's is assumed the table contains OID/string pairs, and the contents
        * of the table are copied into an internal table as part of the
        * construction process. The ordering ArrayList should contain the OIDs
        * in the order they are meant to be encoded or printed in ToString.</p>
        * <p>
        * The passed in converter will be used to convert the strings into their
        * ASN.1 counterparts.</p>
        */
        public X509Name(
            ArrayList				ordering,
            Hashtable				attributes,
            X509NameEntryConverter	converter)
        {
			this.converter = converter;

			foreach (DerObjectIdentifier oid in ordering)
			{
				object attribute = attributes[oid];
				if (attribute == null)
				{
					throw new ArgumentException("No attribute for object id - " + oid + " - passed to distinguished name");
				}

				this.ordering.Add(oid);
				this.added.Add(false);
				this.values.Add(attribute); // copy the hash table
			}
        }

		/**
        * Takes two vectors one of the oids and the other of the values.
        */
        public X509Name(
            ArrayList	oids,
            ArrayList	values)
            : this(oids, values, new X509DefaultEntryConverter())
        {
        }

		/**
        * Takes two vectors one of the oids and the other of the values.
        * <p>
        * The passed in converter will be used to convert the strings into their
        * ASN.1 counterparts.</p>
        */
        public X509Name(
            ArrayList				oids,
            ArrayList				values,
            X509NameEntryConverter	converter)
        {
            this.converter = converter;

			if (oids.Count != values.Count)
            {
                throw new ArgumentException("'oids' must be same length as 'values'.");
            }

			for (int i = 0; i < oids.Count; i++)
            {
                this.ordering.Add(oids[i]);
                this.values.Add(values[i]);
                this.added.Add(false);
            }
        }

		/**
        * Takes an X509 dir name as a string of the format "C=AU, ST=Victoria", or
        * some such, converting it into an ordered set of name attributes.
        */
        public X509Name(
            string dirName)
            : this(DefaultReverse, DefaultLookup, dirName)
        {
        }

		/**
        * Takes an X509 dir name as a string of the format "C=AU, ST=Victoria", or
        * some such, converting it into an ordered set of name attributes with each
        * string value being converted to its associated ASN.1 type using the passed
        * in converter.
        */
        public X509Name(
            string					dirName,
            X509NameEntryConverter	converter)
            : this(DefaultReverse, DefaultLookup, dirName, converter)
        {
        }

		/**
        * Takes an X509 dir name as a string of the format "C=AU, ST=Victoria", or
        * some such, converting it into an ordered set of name attributes. If reverse
        * is true, create the encoded version of the sequence starting from the
        * last element in the string.
        */
        public X509Name(
            bool	reverse,
            string	dirName)
            : this(reverse, DefaultLookup, dirName)
        {
        }

		/**
        * Takes an X509 dir name as a string of the format "C=AU, ST=Victoria", or
        * some such, converting it into an ordered set of name attributes with each
        * string value being converted to its associated ASN.1 type using the passed
        * in converter. If reverse is true the ASN.1 sequence representing the DN will
        * be built by starting at the end of the string, rather than the start.
        */
        public X509Name(
            bool					reverse,
            string					dirName,
            X509NameEntryConverter	converter)
            : this(reverse, DefaultLookup, dirName, converter)
        {
        }

		/**
        * Takes an X509 dir name as a string of the format "C=AU, ST=Victoria", or
        * some such, converting it into an ordered set of name attributes. lookUp
        * should provide a table of lookups, indexed by lowercase only strings and
        * yielding a DerObjectIdentifier, other than that OID. and numeric oids
        * will be processed automatically.
        * <br/>
        * If reverse is true, create the encoded version of the sequence
        * starting from the last element in the string.
        * @param reverse true if we should start scanning from the end (RFC 2553).
        * @param lookUp table of names and their oids.
        * @param dirName the X.500 string to be parsed.
        */
        public X509Name(
            bool		reverse,
            Hashtable	lookUp,
            string		dirName)
            : this(reverse, lookUp, dirName, new X509DefaultEntryConverter())
        {
        }

		private DerObjectIdentifier DecodeOid(
            string		name,
            IDictionary lookUp)
        {
            if (name.ToUpper(CultureInfo.InvariantCulture).StartsWith("OID."))
            {
                return new DerObjectIdentifier(name.Substring(4));
            }
            else if (name[0] >= '0' && name[0] <= '9')
            {
                return new DerObjectIdentifier(name);
            }

			DerObjectIdentifier oid = (DerObjectIdentifier)lookUp[name.ToLower(CultureInfo.InvariantCulture)];
            if (oid == null)
            {
                throw new ArgumentException("Unknown object id - " + name + " - passed to distinguished name");
            }

			return oid;
        }

		/**
        * Takes an X509 dir name as a string of the format "C=AU, ST=Victoria", or
        * some such, converting it into an ordered set of name attributes. lookUp
        * should provide a table of lookups, indexed by lowercase only strings and
        * yielding a DerObjectIdentifier, other than that OID. and numeric oids
        * will be processed automatically. The passed in converter is used to convert the
        * string values to the right of each equals sign to their ASN.1 counterparts.
        * <br/>
        * @param reverse true if we should start scanning from the end, false otherwise.
        * @param lookUp table of names and oids.
        * @param dirName the string dirName
        * @param converter the converter to convert string values into their ASN.1 equivalents
        */
        public X509Name(
            bool					reverse,
            IDictionary				lookUp,
            string					dirName,
            X509NameEntryConverter	converter)
        {
            this.converter = converter;
            X509NameTokenizer nTok = new X509NameTokenizer(dirName);

			while (nTok.HasMoreTokens())
            {
                string token = nTok.NextToken();
                int index = token.IndexOf('=');

				if (index == -1)
                {
                    throw new ArgumentException("badly formated directory string");
                }

				string name = token.Substring(0, index);
                string value = token.Substring(index + 1);
                DerObjectIdentifier	oid = DecodeOid(name, lookUp);

				if (value.IndexOf('+') > 0)
                {
                    X509NameTokenizer vTok = new X509NameTokenizer(value, '+');

					this.ordering.Add(oid);
                    this.values.Add(vTok.NextToken());
                    this.added.Add(false);

					while (vTok.HasMoreTokens())
                    {
                        string sv = vTok.NextToken();
                        int ndx = sv.IndexOf('=');

                        string nm = sv.Substring(0, ndx);
                        string vl = sv.Substring(ndx + 1);
                        this.ordering.Add(DecodeOid(nm, lookUp));
                        this.values.Add(vl);
                        this.added.Add(true);
                    }
                }
                else
                {
                    this.ordering.Add(oid);
                    this.values.Add(value);
                    this.added.Add(false);
                }
            }

			if (reverse)
            {
//				this.ordering.Reverse();
//				this.values.Reverse();
//				this.added.Reverse();
				ArrayList o = new ArrayList();
				ArrayList v = new ArrayList();
				ArrayList a = new ArrayList();
				int count = 1;

				for (int i = 0; i < this.ordering.Count; i++)
				{
					if (!((bool) this.added[i]))
					{
						count = 0;
					}

					int index = count++;

					o.Insert(index, this.ordering[i]);
					v.Insert(index, this.values[i]);
					a.Insert(index, this.added[i]);
				}

				this.ordering = o;
				this.values = v;
				this.added = a;
			}
        }

		/**
		* return an ArrayList of the oids in the name, in the order they were found.
		*/
        public ArrayList GetOids()
        {
			return (ArrayList) ordering.Clone();
        }

		/**
		 * return an ArrayList of the values found in the name, in the order they
		 * were found, with the DN label corresponding to passed in oid.
		 */
		public ArrayList GetValues(
			DerObjectIdentifier oid)
		{
			ArrayList v = new ArrayList();

			for (int i = 0; i != values.Count; i++)
			{
				if (ordering[i].Equals(oid))
				{
					v.Add(values[i]);
				}
			}

			return v;
		}

		/**
        * return an ArrayList of the values found in the name, in the order they
        * were found.
        */
        public ArrayList GetValues()
        {
			return (ArrayList) values.Clone();
        }

		public override Asn1Object ToAsn1Object()
        {
            if (seq == null)
            {
                Asn1EncodableVector vec = new Asn1EncodableVector();
                Asn1EncodableVector sVec = new Asn1EncodableVector();
                DerObjectIdentifier lstOid = null;

				for (int i = 0; i != ordering.Count; i++)
                {
                    DerObjectIdentifier oid = (DerObjectIdentifier)ordering[i];
					string str = (string)values[i];

					if (lstOid == null
                        || ((bool)this.added[i]))
                    {
                    }
                    else
                    {
                        vec.Add(new DerSet(sVec));
                        sVec = new Asn1EncodableVector();
                    }

					sVec.Add(
						new DerSequence(
							oid,
							converter.GetConvertedValue(oid, str)));

					lstOid = oid;
                }

				vec.Add(new DerSet(sVec));

				seq = new DerSequence(vec);
            }

            return seq;
        }

		[Obsolete("Use 'Equivalent(X509Name, int)' instead")]
		public bool Equals(
			X509Name	other,
			bool		inOrder)
		{
			return Equivalent(other, inOrder);
		}

		/// <param name="other">The X509Name object to test equivalency against.</param>
		/// <param name="inOrder">If true, the order of elements must be the same,
		/// as well as the values associated with each element.</param>
		public bool Equivalent(
			X509Name	other,
			bool		inOrder)
		{
			if (!inOrder)
				return this.Equivalent(other);

			if (other == null)
				return false;

			if (other == this)
				return true;

			int orderingSize = ordering.Count;

			if (orderingSize != other.ordering.Count)
				return false;

			for (int i = 0; i < orderingSize; i++)
			{
				DerObjectIdentifier oid = (DerObjectIdentifier) ordering[i];
				DerObjectIdentifier oOid = (DerObjectIdentifier) other.ordering[i];

				if (!oid.Equals(oOid))
					return false;

				string val = (string) values[i];
				string oVal = (string) other.values[i];

				if (!equivalentStrings(val, oVal))
					return false;
			}

			return true;
		}

		[Obsolete("Use 'Equivalent(X509Name)' instead")]
		public bool Equals(
			X509Name other)
		{
			return Equivalent(other);
		}

		/**
		 * test for equivalence - note: case is ignored.
		 */
		public bool Equivalent(
			X509Name other)
		{
			if (other == null)
				return false;

			if (other == this)
				return true;

			int orderingSize = ordering.Count;

			if (orderingSize != other.ordering.Count)
			{
				return false;
			}

			bool[] indexes = new bool[orderingSize];
			int start, end, delta;

			if (ordering[0].Equals(other.ordering[0]))   // guess forward
			{
				start = 0;
				end = orderingSize;
				delta = 1;
			}
			else  // guess reversed - most common problem
			{
				start = orderingSize - 1;
				end = -1;
				delta = -1;
			}

			for (int i = start; i != end; i += delta)
			{
				bool found = false;
				DerObjectIdentifier  oid = (DerObjectIdentifier)ordering[i];
				string value = (string)values[i];

				for (int j = 0; j < orderingSize; j++)
				{
					if (indexes[j])
					{
						continue;
					}

					DerObjectIdentifier oOid = (DerObjectIdentifier)other.ordering[j];

					if (oid.Equals(oOid))
					{
						string oValue = (string)other.values[j];

						if (equivalentStrings(value, oValue))
						{
							indexes[j] = true;
							found      = true;
							break;
						}
					}
				}

				if (!found)
				{
					return false;
				}
			}

			return true;
		}

		private bool equivalentStrings(
			string	s1,
			string	s2)
		{
			string value = s1.ToLower(CultureInfo.InvariantCulture).Trim();
			string oValue = s2.ToLower(CultureInfo.InvariantCulture).Trim();

			if (!value.Equals(oValue))
			{
				value = stripInternalSpaces(value);
				oValue = stripInternalSpaces(oValue);

				if (!value.Equals(oValue))
				{
					return false;
				}
			}

			return true;
		}

		private string stripInternalSpaces(
			string str)
		{
			StringBuilder res = new StringBuilder();

			if (str.Length != 0)
			{
				char c1 = str[0];

				res.Append(c1);

				for (int k = 1; k < str.Length; k++)
				{
					char c2 = str[k];
					if (!(c1 == ' ' && c2 == ' '))
					{
						res.Append(c2);
					}
					c1 = c2;
				}
			}

			return res.ToString();
		}

		private void AppendValue(
            StringBuilder		buf,
            Hashtable			oidSymbols,
            DerObjectIdentifier	oid,
            string				val)
        {
            string sym = (string) oidSymbols[oid];

            if (sym != null)
            {
                buf.Append(sym);
            }
            else
            {
                buf.Append(oid.Id);
            }

            buf.Append('=');

            int index = buf.Length;

            buf.Append(val);

            int end = buf.Length;

            while (index != end)
            {
                if ((buf[index] == ',')
                || (buf[index] == '"')
                || (buf[index] == '\\')
                || (buf[index] == '+')
                || (buf[index] == '<')
                || (buf[index] == '>')
                || (buf[index] == ';'))
                {
                    buf.Insert(index++, "\\");
                    end++;
                }

                index++;
            }
        }

        /**
        * convert the structure to a string - if reverse is true the
        * oids and values are listed out starting with the last element
        * in the sequence (ala RFC 2253), otherwise the string will begin
        * with the first element of the structure. If no string definition
        * for the oid is found in oidSymbols the string value of the oid is
        * added. Two standard symbol tables are provided DefaultSymbols, and
        * RFC2253Symbols as part of this class.
        *
        * @param reverse if true start at the end of the sequence and work back.
        * @param oidSymbols look up table strings for oids.
        */
        public string ToString(
            bool		reverse,
            Hashtable	oidSymbols)
        {
			StringBuilder buf = new StringBuilder();
			ArrayList components = new ArrayList();
			bool first = true;

			StringBuilder ava = null;

			for (int i = 0; i < ordering.Count; i++)
			{
				if ((bool) added[i])
				{
					ava.Append('+');
					AppendValue(ava, oidSymbols,
						(DerObjectIdentifier)ordering[i],
						(string)values[i]);
				}
				else
				{
					ava = new StringBuilder();
					AppendValue(ava, oidSymbols,
						(DerObjectIdentifier)ordering[i],
						(string)values[i]);
					components.Add(ava);
				}
			}

			if (reverse)
			{
				for (int i = components.Count - 1; i >= 0; i--)
				{
					if (first)
					{
						first = false;
					}
					else
					{
						buf.Append(',');
					}

					buf.Append(components[i].ToString());
				}
			}
			else
			{
				for (int i = 0; i < components.Count; i++)
				{
					if (first)
					{
						first = false;
					}
					else
					{
						buf.Append(',');
					}

					buf.Append(components[i].ToString());
				}
			}

			return buf.ToString();
		}

		public override string ToString()
        {
            return ToString(DefaultReverse, DefaultSymbols);
        }
    }
}
