File: Metadata.cs

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using System;
using System.IO;
using System.Collections;
using System.Text;
using System.Reflection;

namespace PEAPI {

	#region Enums

	/// <summary>
	/// flags for the assembly (.corflags)
	/// </summary>
	public enum CorFlags {CF_IL_ONLY = 1, CF_32_BITREQUIRED = 2,
		CF_STRONGNAMESIGNED = 8, CF_TRACKDEBUGDATA = 0x10000 }

	/// <summary>
	/// subsystem for the assembly (.subsystem)
	/// </summary>
	public enum SubSystem { Native = 1, Windows_GUI = 2, 
		Windows_CUI = 3, OS2_CUI = 5, POSIX_CUI = 7, Native_Windows = 8, 
		Windows_CE_GUI = 9}

	/// <summary>
	/// Hash algorithms for the assembly
	/// </summary>
	public enum HashAlgorithm { None, SHA1 }

	/// <summary>
	/// Attributes for this assembly
	/// </summary>
	public enum AssemAttr { Retargetable = 0x100, EnableJITCompileTracking = 0x8000, 
		DisableJITCompileOptimizer = 0x4000}

	/// <summary>
	/// Method call conventions
	/// </summary>
	[Flags]
	public enum CallConv { Default, Cdecl, Stdcall, Thiscall, 
		Fastcall, Vararg, Instance = 0x20, Generic = 0x10, InstanceExplicit = 0x60 }

	/// <summary>
	/// Type custom modifier
	/// </summary>
	public enum CustomModifier { modreq = 0x1F, modopt };

	/// <summary>
	/// Attibutes for a class
	/// </summary>
	[Flags]
	public enum TypeAttr {Private, Public, NestedPublic, NestedPrivate, 
		NestedFamily, NestedAssembly, NestedFamAndAssem, NestedFamOrAssem, 
		SequentialLayout, ExplicitLayout = 0x10, Interface = 0x20, 
		Abstract = 0x80, PublicAbstract = 0x81, Sealed = 0x100, 
		PublicSealed = 0x101, SpecialName = 0x400, RTSpecialName = 0x800, 
		Import = 0x1000, Serializable = 0x2000, UnicodeClass = 0x10000,
		AutoClass = 0x20000, HasSecurity = 0x40000, BeforeFieldInit = 0x100000,
		Forwarder = 0x200000,
		VisibilityMask = 0x07 }

	/// <summary>
	/// Attributes for a field
	/// </summary>
	public enum FieldAttr {Default, Private, FamAndAssem, Assembly, 
		Family, FamOrAssem, Public, Static = 0x10, PublicStatic = 0x16, 
		Initonly = 0x20, Literal = 0x40, Notserialized = 0x80, 
		SpecialName = 0x200, RTSpecialName = 0x400, HasFieldMarshal = 0x1000 }

	/// <summary>
	/// Attributes for a method
	/// </summary>
	public enum MethAttr { Default, Private, FamAndAssem, Assembly,
		Family, FamOrAssem, Public, Static = 0x0010, PublicStatic = 0x16, 
		Final = 0x0020, PublicStaticFinal = 0x36, Virtual = 0x0040, 
		PrivateVirtual, PublicVirtual = 0x0046, HideBySig = 0x0080, 
		NewSlot = 0x0100, Strict = 0x200, Abstract = 0x0400, SpecialName = 0x0800,
		RTSpecialName = 0x1000, SpecialRTSpecialName = 0x1800, 
		HasSecurity = 0x4000, RequireSecObject = 0x8000}

	/// <summary>
	/// Attributes for .pinvokeimpl method declarations
	/// </summary>
	public enum PInvokeAttr { nomangle = 1, ansi = 2, unicode = 4, autochar = 6,
		bestfit_on = 0x0010, bestfit_off = 0x0020, bestfit_mask = 0x0030,
		lasterr = 0x0040, winapi = 0x0100, cdecl = 0x0200,
		stdcall = 0x0300, thiscall = 0x0400, fastcall = 0x0500,
		charmaperror_on = 0x1000, charmaperror_off = 0x2000
	}

	/// <summary>
	/// Implementation attributes for a method
	/// </summary>
	public enum ImplAttr { IL, Native, Runtime = 0x03, Unmanaged = 0x04,
		ForwardRef = 0x10, PreserveSig = 0x0080, InternalCall = 0x1000, 
		Synchronised = 0x0020, Synchronized = 0x0020, NoInLining = 0x0008, NoOptimization = 0x0040, Optil = 0x0002,
		AggressiveInlining = 0x0100
	}

	/// <summary>
	/// Storage location for initial field data
	/// </summary>
	public enum DataSegment { Data, TLS, CIL }

	/// <summary>
	/// Modes for a parameter
	/// </summary>
	public enum ParamAttr { Default, In, Out, Opt = 16, HasDefault = 0x1000, HasFieldMarshal = 0x2000 }

	/// <summary>
	/// CIL instructions
	/// </summary>
	public enum Op { nop, breakOp, ldarg_0, ldarg_1, ldarg_2, ldarg_3,
		ldloc_0, ldloc_1, ldloc_2, ldloc_3, stloc_0, stloc_1, stloc_2, stloc_3, 
		ldnull = 0x14, ldc_i4_m1, ldc_i4_0, ldc_i4_1, ldc_i4_2, ldc_i4_3, 
		ldc_i4_4, ldc_i4_5, ldc_i4_6, ldc_i4_7, ldc_i4_8, dup = 0x25, pop, 
		ret = 0x2A, ldind_i1 = 0x46, ldind_u1, ldind_i2, ldind_u2, ldind_i4, 
		ldind_u4, ldind_i8, ldind_i,  ldind_r4, ldind_r8, ldind_ref, stind_ref, 
		stind_i1, stind_i2, stind_i4, stind_i8, stind_r4, stind_r8, add, sub, mul,
		div, div_un, rem, rem_un, and, or, xor, shl, shr, shr_un, neg, not, 
		conv_i1, conv_i2, conv_i4, conv_i8, conv_r4, conv_r8, conv_u4, conv_u8, 
		conv_r_un = 0x76, throwOp = 0x7A, conv_ovf_i1_un = 0x82, conv_ovf_i2_un,
		conv_ovf_i4_un, conv_ovf_i8_un, conf_ovf_u1_un, conv_ovf_u2_un, 
		conv_ovf_u4_un, conv_ovf_u8_un, conv_ovf_i_un, conv_ovf_u_un, 
		ldlen = 0x8E, ldelem_i1 = 0x90, ldelem_u1, ldelem_i2, ldelem_u2, 
		ldelem_i4, ldelem_u4, ldelem_i8, ldelem_i, ldelem_r4, ldelem_r8, 
		ldelem_ref, stelem_i, stelem_i1, stelem_i2, stelem_i4, stelem_i8, stelem_r4 = 0xA0, stelem_r8,
		stelem_ref, conv_ovf_i1 = 0xb3, conv_ovf_u1, conv_ovf_i2, conv_ovf_u2, 
		conv_ovf_i4, conv_ovf_u4, conv_ovf_i8, conv_ovf_u8, ckfinite = 0xC3, 
		conv_u2 = 0xD1, conv_u1, conv_i, conv_ovf_i, conv_ovf_u, add_ovf, 
		add_ovf_un, mul_ovf, mul_ovf_un, sub_ovf, sub_ovf_un, endfinally, 
		stind_i = 0xDF, conv_u, arglist = 0xFE00, ceq, cgt, cgt_un, clt, clt_un, 
		localloc = 0xFE0F, endfilter = 0xFE11, volatile_ = 0xFE13, tail_, 
		cpblk = 0xFE17, initblk, rethrow = 0xFE1A, refanytype = 0xFE1D, readonly_ = 0xFE1E }

	/// <summary>
	/// CIL instructions requiring an integer parameter
	/// </summary>
	public enum IntOp {ldarg_s = 0x0E, ldarga_s, starg_s, ldloc_s, ldloca_s, 
		stloc_s, ldc_i4_s = 0x1F, ldc_i4, ldarg = 0xFE09,
		ldarga, starg, ldloc, ldloca, stloc, unaligned = 0xFE12 }

	/// <summary>
	/// CIL instructions requiring a field parameter
	/// </summary>
	public enum FieldOp {ldfld = 0x7B, ldflda, stfld, ldsfld, ldsflda,
		stsfld, ldtoken = 0xD0 }

	/// <summary>
	/// CIL instructions requiring a method parameter
	/// </summary>
	public enum MethodOp {jmp = 0x27, call, callvirt = 0x6F, newobj = 0x73, 
		ldtoken = 0xD0, ldftn = 0xFE06, ldvirtfn }

	/// <summary>
	/// CIL instructions requiring a type parameter
	/// </summary>
	public enum TypeOp {cpobj = 0x70, ldobj, castclass = 0x74, isinst, 
		unbox = 0x79, stobj = 0x81, box = 0x8C, newarr, 
		ldelema = 0x8F, refanyval = 0xC2, mkrefany = 0xC6, 
		ldtoken = 0xD0, initobj = 0xFE15, constrained = 0xFE16, 
		sizeOf = 0xFE1C, ldelem = 0xA3, stelem = 0xA4, unbox_any }

	/// <summary>
	/// CIL branch instructions
	/// </summary>
	public enum BranchOp {
		// short branches
		br_s = 0x2B, brfalse_s, brtrue_s, beq_s, bge_s, bgt_s,
		ble_s, blt_s, bne_un_s, bge_un_s, bgt_un_s, ble_un_s, blt_un_s,
		// long branches
		br = 0x38, brfalse, brtrue, beq, bge, bgt, ble, blt,
		bne_un, bge_un, bgt_un, ble_un, blt_un,

		leave = 0xDD, leave_s }

	/// <summary>
	/// Index for all the tables in the meta data
	/// </summary>
	public enum MDTable { Module, TypeRef, TypeDef, Field = 0x04, Method = 0x06,
		Param = 0x08, InterfaceImpl, MemberRef, Constant, CustomAttribute, 
		FieldMarshal, DeclSecurity, ClassLayout, FieldLayout, StandAloneSig, 
		EventMap, Event = 0x14, PropertyMap, Property = 0x17, MethodSemantics, 
		MethodImpl, ModuleRef, TypeSpec, ImplMap, FieldRVA, Assembly = 0x20, 
		AssemblyProcessor, AssemblyOS, AssemblyRef, AssemblyRefProcessor, 
		AssemblyRefOS, File, ExportedType, ManifestResource, NestedClass,
		GenericParam, MethodSpec, GenericParamConstraint  }

	public enum SafeArrayType { int16 = 2, int32, float32, float64,
		currency, date, bstr, dispatch, error, boolean, variant, unknown,
		Decimal, int8 = 16, uint8, uint16, uint32, Int = 22, UInt }

	internal enum CIx { TypeDefOrRef, HasConst, HasCustomAttr, HasFieldMarshal,
		HasDeclSecurity, MemberRefParent, HasSemantics, MethodDefOrRef, 
		MemberForwarded, Implementation, CustomAttributeType, ResolutionScope,
		TypeOrMethodDef, MaxCIx }

	internal enum MapType { eventMap, propertyMap, nestedClass }

	public enum ValueClass { ValueType, Enum }

	public enum GenParamType : byte { 
		Var = 0x13, MVar = 0x1E 
	}

	[Flags]
	public enum GenericParamAttributes : ushort {
		VarianceMask  = 0x0003,
		NonVariant    = 0x0000,
		Covariant     = 0x0001,
		Contravariant = 0x0002,

		SpecialConstraintMask = 0x001c,
		ReferenceTypeConstraint = 0x0004,
		NotNullableValueTypeConstraint = 0x0008,
		DefaultConstructorConstrait = 0x0010
	}

	/* Taken from Mono.Cecil */
	public enum SecurityAction : short {
		Request = 1,
		Demand = 2,
		Assert = 3,
		Deny = 4,
		PermitOnly = 5,
		LinkDemand = 6,
		InheritDemand = 7,
		RequestMinimum = 8,
		RequestOptional = 9,
		RequestRefuse = 10,
		PreJitGrant = 11,
		PreJitDeny = 12,
		NonCasDemand = 13,
		NonCasLinkDemand = 14,
		NonCasInheritance = 15,
		LinkDemandChoice = 16,
		InheritDemandChoice = 17,
		DemandChoice = 18
	}

	#endregion

	/**************************************************************************/  
	/// <summary>
	/// Base class for all Meta Data table elements
	/// </summary>

	public abstract class MetaDataElement: IComparable {
		protected ArrayList customAttributes;
		private uint row = 0;
		protected bool done = false;
		protected MDTable tabIx;
		protected bool sortTable = false;
		//Temporary hack.. 
		private bool has_custom_attrs = false;

		internal MetaDataElement() { }

		public uint Row {
			get {
				return row;
			}
			set {
				row = value;
			}
		}

		public bool HasCustomAttr {
			get { return has_custom_attrs; }
			set { has_custom_attrs = value; }
		}

		internal virtual uint GetCodedIx(CIx code) { return 0; }

		/// <summary>
		/// Add a custom attribute to this item
		/// </summary>
		/// <param name="ctorMeth">the constructor method for this attribute</param>
		/// <param name="val">the byte value of the parameters</param>
		public void AddCustomAttribute(Method ctorMeth, byte[] val) 
		{
			if (customAttributes == null) {
				customAttributes = new ArrayList();
			} 
			customAttributes.Add(new CustomAttribute(this,ctorMeth,val));
		}

		/// <summary>
		/// Add a custom attribute to this item
		/// </summary>
		/// <param name="ctorMeth">the constructor method for this attribute</param>
		/// <param name="val">the constant values of the parameters</param>
		public void AddCustomAttribute(Method ctorMeth, Constant[] cVals) 
		{
			if (customAttributes == null) {
				customAttributes = new ArrayList();
			} 
			//      customAttributes.Add(new CustomAttribute(this,ctorMeth,cVals));
		}

		internal uint Token() 
		{
			return (((uint)tabIx << 24) | row);
		}

		internal virtual void BuildTables(MetaData md) 
		{
			done = true;
		}

		internal virtual uint Size(MetaData md) 
		{
			return 0;
		}

		internal virtual void Write(FileImage output) {   }

		internal virtual uint SortKey() 
		{ 
			throw new PEFileException("Trying to sort table of " + this);
			//return 0; 
		}

		internal virtual uint SortKey2()
		{
			return 0;
		}

		public int CompareTo(object obj) 
		{
			uint otherKey = ((MetaDataElement)obj).SortKey();
			uint thisKey = SortKey();

			if (thisKey == otherKey)  {

				otherKey = ((MetaDataElement)obj).SortKey2();
				thisKey = SortKey2();
				if (thisKey == otherKey)
					return 0;
				if (thisKey < otherKey)
					return -1;
				return 1;
			}
			if (thisKey < otherKey) return -1;

			return 1;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Layout information for a class (.class [sequential | explicit])
	/// </summary>
	internal class ClassLayout : MetaDataElement {

		ClassDef parent;
		ushort packSize = 0;
		uint classSize = 0;

		internal ClassLayout(int pack, int cSize, ClassDef par) 
		{
			packSize = (ushort)pack;
			classSize = (uint)cSize;
			parent = par;
			tabIx = MDTable.ClassLayout;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 6 + md.TableIndexSize(MDTable.TypeDef);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(packSize);
			output.Write(classSize);
			output.WriteIndex(MDTable.TypeDef,parent.Row);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Summary description for ConstantElem.
	/// </summary>
	internal class ConstantElem : MetaDataElement {

		MetaDataElement parent;
		Constant cValue;
		uint valIx = 0;

		internal ConstantElem(MetaDataElement parent, Constant val) 
		{
			this.parent = parent;
			cValue = val;
			tabIx = MDTable.Constant;
			sortTable = true;
		}

		internal override uint SortKey() 
		{  
			return (parent.Row << MetaData.CIxShiftMap[(uint)CIx.HasConst]) 
				| parent.GetCodedIx(CIx.HasConst);
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			valIx = cValue.GetBlobIndex(md);
			done = true;
		}

		internal void AddToBlob(BinaryWriter bw) 
		{
			cValue.Write(bw);
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.CodedIndexSize(CIx.HasConst) + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(cValue.GetTypeIndex());
			output.Write((byte)0);
			output.WriteCodedIndex(CIx.HasConst,parent);
			output.BlobIndex(valIx);
		}

	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a Custom Attribute (.custom) 
	/// </summary>

	public class CustomAttribute : MetaDataElement {

		MetaDataElement parent;
		Method type;
		uint valIx;
		Constant cVal;
		byte[] byteVal;
		ushort numNamed = 0;
		ArrayList names, vals;

		internal CustomAttribute(MetaDataElement paren, Method constrType, 
				Constant val) {
			parent = paren;
			type = constrType;
			cVal = val;
			tabIx = MDTable.CustomAttribute;

			byteVal = ConstantToByteArray (val);
		}

		static byte[] ConstantToByteArray (Constant c)
		{
			var bac = c as ByteArrConst;
			if (bac != null)
				return bac.val;

			var ms = new MemoryStream ();
			// Version info
			ms.WriteByte (1);
			ms.WriteByte (0);

			if (c == null) {
				ms.WriteByte (0);
				ms.WriteByte (0);
				return ms.ToArray ();
			}

			var sc = c as StringConst;
			if (sc != null) {
				string value = sc.val;
				if (value == null)
					throw new NotImplementedException ();

				var buf = Encoding.UTF8.GetBytes (value);
				MetaData.CompressNum ((uint) buf.Length, ms);
				var byteVal = ms.ToArray ();
				System.Array.Resize (ref byteVal, (int) ms.Length + buf.Length + 2);
				System.Array.Copy (buf, 0, byteVal, ms.Length, buf.Length);
				return byteVal;
			}

			var ac = c as ArrayConstant;
			if (ac != null) {
				var bw = new BinaryWriter (ms);
				if (ac.ExplicitSize != null)
					bw.Write (ac.ExplicitSize.Value);
				ac.Write (bw);
				bw.Write ((short)0);
				return ms.ToArray ();
			}

			var bc = c as DataConstant;
			if (bc != null) {
				var bw = new BinaryWriter (ms);
				bc.Write (bw);
				bw.Write ((short)0);
				return ms.ToArray ();
			}

			throw new NotImplementedException (c.GetType ().ToString ());
		}

		internal CustomAttribute(MetaDataElement paren, Method constrType,
				byte[] val) {
			parent = paren;
			type = constrType;
			tabIx = MDTable.CustomAttribute;
			byteVal = val;
		}

		internal override uint SortKey() 
		{
			return (parent.Row << MetaData.CIxShiftMap[(uint)CIx.HasCustomAttr])
				| parent.GetCodedIx(CIx.HasCustomAttr);
		}

		public void AddFieldOrProp(string name, Constant val) 
		{
			if (numNamed == 0) {
				names = new ArrayList();
				vals = new ArrayList();
			}
			names.Add(name);
			vals.Add(val);
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			md.AddToTable(MDTable.CustomAttribute, this);
			if (byteVal == null) {
				valIx = 0;
				return;
			}

			BinaryWriter bw = new BinaryWriter(new MemoryStream());
			bw.Write(byteVal);
			MemoryStream str = (MemoryStream)bw.BaseStream;
			valIx = md.AddToBlobHeap(str.ToArray());
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.CodedIndexSize(CIx.HasCustomAttr) + md.CodedIndexSize(CIx.CustomAttributeType) + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteCodedIndex(CIx.HasCustomAttr,parent);
			output.WriteCodedIndex(CIx.CustomAttributeType,type);
			output.BlobIndex(valIx);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for security permissions for a class or a method
	/// </summary>

	public abstract class BaseDeclSecurity : MetaDataElement {

		ushort action;
		MetaDataElement parent;
		uint permissionIx;

		internal BaseDeclSecurity(MetaDataElement paren, ushort act)
		{
			parent = paren;
			action = act;
			tabIx = MDTable.DeclSecurity;
		}

		internal override uint SortKey() 
		{
			return (parent.Row << MetaData.CIxShiftMap[(uint)CIx.HasDeclSecurity])
				| parent.GetCodedIx(CIx.HasDeclSecurity);
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.CodedIndexSize(CIx.HasDeclSecurity) + md.BlobIndexSize();
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;

			BinaryWriter bw = new BinaryWriter (new MemoryStream ());
			md.AddToTable (MDTable.DeclSecurity, this);
			MemoryStream str = (MemoryStream)bw.BaseStream;
			WriteSig (bw);
			permissionIx = md.AddToBlobHeap(str.ToArray());

			done = true;
		}

		internal abstract void WriteSig (BinaryWriter bw);

		internal sealed override void Write(FileImage output) 
		{
			output.Write(action);
			output.WriteCodedIndex(CIx.HasDeclSecurity,parent);
			output.BlobIndex(permissionIx);
		}

	}

	public class DeclSecurity : BaseDeclSecurity {

		byte [] byteVal;

		internal DeclSecurity(MetaDataElement paren, ushort act, byte [] val)        
			: base (paren, act)
		{
			byteVal = val;
		}

		internal override void WriteSig (BinaryWriter bw)
		{
			bw.Write (byteVal);
		}

	}

	public class DeclSecurity_20 : BaseDeclSecurity {

		PermissionSet ps;

		internal DeclSecurity_20 (MetaDataElement paren, ushort act, PermissionSet ps)
			: base (paren, act)
		{
                        this.ps = ps;
		}

		internal override void WriteSig (BinaryWriter bw)
		{
			ps.Write (bw);
		}
	}

	public class PermissionMember {

		MemberTypes member_type;
		PEAPI.Type type;
		string name;
		object value;

		public PermissionMember (MemberTypes member_type, PEAPI.Type type, string name, object value)
		{
			this.member_type = member_type;
			this.type = type;
			this.name = name;
			this.value = value;
		}

		public void Write (BinaryWriter bw)
		{
			byte [] b;

			if (member_type == MemberTypes.Field)
				bw.Write ((byte) 0x53);
			else
				//Property
				bw.Write ((byte) 0x54);

			if (type is PrimitiveType) {
				bw.Write (type.GetTypeIndex ());
			} else {
				//must be enum
				bw.Write ((byte) 0x55); //ENUM

				b = Encoding.UTF8.GetBytes (((ClassRef) type).TypeName ());
				MetaData.CompressNum ((uint) b.Length, (MemoryStream) bw.BaseStream);
				bw.Write (b);
			}
			
			b = Encoding.UTF8.GetBytes (name);
			MetaData.CompressNum ((uint) b.Length, (MemoryStream) bw.BaseStream);
			bw.Write (b);

			((Constant) value).Write (bw);
		}

	}

	public class Permission
	{
		PEAPI.Type type;

		//PermissionMembers
		ArrayList members;
		string name;

		public Permission (PEAPI.Type type, string name)
		{
			this.type = type;
			this.name = name;
		}

		public void AddMember (PEAPI.PermissionMember member)
		{
			if (members == null)
				members = new ArrayList ();

			members.Add (member);
		}

		public void Write (BinaryWriter bw)
		{
			byte [] b = Encoding.UTF8.GetBytes (name);
			MetaData.CompressNum ((uint) b.Length, (MemoryStream) bw.BaseStream);
			bw.Write (b);

			BinaryWriter perm_writer = new BinaryWriter (new MemoryStream (), Encoding.Unicode);
			MemoryStream str = (MemoryStream) perm_writer.BaseStream;

			MetaData.CompressNum ((uint) members.Count, str);//number of params
			foreach (PermissionMember member in members)
				member.Write (perm_writer);

			bw.Write ((byte) str.Length); //(optional) parameters length
			bw.Write (str.ToArray ());
		}
	}

	public class PermissionSet 
	{
		PEAPI.SecurityAction sec_action;
		ArrayList permissions;

		public PermissionSet (PEAPI.SecurityAction sec_action)
		{
			this.sec_action = sec_action;
		}

		public void AddPermission (PEAPI.Permission perm)
		{
			if (permissions == null)
				permissions = new ArrayList ();

			permissions.Add (perm);
		}

		public void Write (BinaryWriter bw)
		{
			bw.Write ((byte) 0x2e);
			MetaData.CompressNum ((uint) permissions.Count, (MemoryStream) bw.BaseStream);

			foreach (Permission perm in permissions)
				perm.Write (bw);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for layout information for a field
	/// </summary>

	public class FieldLayout : MetaDataElement {

		Field field;
		uint offset;

		internal FieldLayout(Field field, uint offset)      
		{
			this.field = field;
			this.offset = offset;
			tabIx = MDTable.FieldLayout;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 4 + md.TableIndexSize(MDTable.Field);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(offset);
			output.WriteIndex(MDTable.Field,field.Row);
		}

	}

	/*****************************************************************************/  
	/// <summary>
	/// Marshalling information for a field or param
	/// </summary>
	public class FieldMarshal : MetaDataElement {

		MetaDataElement field;
		NativeType nt;
		uint ntIx;

		internal FieldMarshal(MetaDataElement field, NativeType nType)      
		{
			this.field = field;
			this.nt = nType;
			tabIx = MDTable.FieldMarshal;
		}

		internal override uint SortKey() 
		{
			return (field.Row << MetaData.CIxShiftMap[(uint)CIx.HasFieldMarshal])
				| field.GetCodedIx(CIx.HasFieldMarshal);
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			ntIx = md.AddToBlobHeap(nt.ToBlob());
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.CodedIndexSize(CIx.HasFieldMarshal) + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteCodedIndex(CIx.HasFieldMarshal,field);
			output.BlobIndex(ntIx);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for the address of a field's value in the PE file
	/// </summary>
	public class FieldRVA : MetaDataElement {

		Field field;
		DataConstant data;

		internal FieldRVA(Field field, DataConstant data)   
		{
			this.field = field;
			this.data = data;
			tabIx = MDTable.FieldRVA;
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			md.AddData(data);
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 4 + md.TableIndexSize(MDTable.Field);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteDataRVA(data.DataOffset);
			output.WriteIndex(MDTable.Field,field.Row);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a file referenced in THIS assembly/module (.file)
	/// </summary>
	public class FileRef : MetaDataElement {

		private static readonly uint NoMetaData = 0x1;
		uint nameIx = 0, hashIx = 0;
		uint flags = 0;
		protected string name;

		internal FileRef(string name, byte[] hashBytes, bool metaData,
				bool entryPoint, MetaData md) {
			if (!metaData) flags = NoMetaData;
			if (entryPoint) md.SetEntryPoint(this);
			this.name = name;
			nameIx = md.AddToStringsHeap(name);
			hashIx = md.AddToBlobHeap(hashBytes);
			tabIx = MDTable.File;
		}

		internal FileRef(uint nameIx, byte[] hashBytes, bool metaData,
				bool entryPoint, MetaData md) {
			if (!metaData) flags = NoMetaData;
			if (entryPoint) md.SetEntryPoint(this);
			this.nameIx = nameIx;
			hashIx = md.AddToBlobHeap(hashBytes);
			tabIx = MDTable.File;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 4 + md.StringsIndexSize() + md.BlobIndexSize();
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			md.AddToTable(MDTable.File,this);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.StringsIndex(nameIx);
			output.BlobIndex(hashIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 16; 
				case (CIx.Implementation) : return 0;
			}
			return 0;
		}

	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for pinvoke information for a method NOT YET IMPLEMENTED
	/// </summary>
	public class ImplMap : MetaDataElement {

		private static readonly ushort NoMangle = 0x01;
		ushort flags;
		Method meth;
		string importName;
		uint iNameIx;
		ModuleRef importScope;

		internal ImplMap(ushort flag, Method implMeth, string iName, ModuleRef mScope) 
		{
			flags = flag;
			meth = implMeth;
			importName = iName;
			importScope = mScope;
			tabIx = MDTable.ImplMap;
			if (iName == null) flags |= NoMangle;
			//throw(new NotYetImplementedException("PInvoke "));
		}

		internal override uint SortKey() 
		{
			return (meth.Row << MetaData.CIxShiftMap[(uint)CIx.MemberForwarded]) 
				| meth.GetCodedIx(CIx.MemberForwarded);
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			iNameIx = md.AddToStringsHeap(importName);
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2+ md.CodedIndexSize(CIx.MemberForwarded) + 
				md.StringsIndexSize() +  md.TableIndexSize(MDTable.ModuleRef);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.WriteCodedIndex(CIx.MemberForwarded,meth);
			output.StringsIndex(iNameIx);
			output.WriteIndex(MDTable.ModuleRef,importScope.Row);
		}

	}

	/**************************************************************************/  

	public class GenericParameter : MetaDataElement {

		MetaDataElement owner;
		MetaData metadata;
		public string name;
		uint nameIx;
		short index;
		GenericParamAttributes attr;

		internal GenericParameter (ClassDef owner, MetaData metadata,
				short index, string name, GenericParamAttributes attr) : this (owner, metadata, index, name, attr, true)
		{
		}

		internal GenericParameter (MethodDef owner, MetaData metadata,
				short index, string name, GenericParamAttributes attr) : this (owner, metadata, index, name, attr, true)
		{
		}

		private GenericParameter (MetaDataElement owner, MetaData metadata,
				short index, string name, GenericParamAttributes attr, bool nadda) {
			this.owner = owner;
			this.metadata = metadata;
			this.index = index;
			tabIx = MDTable.GenericParam;
			this.name = name;
			this.attr = attr;
		}

		internal override uint SortKey() 
		{
			return (owner.Row << MetaData.CIxShiftMap[(uint)CIx.TypeOrMethodDef])
				| owner.GetCodedIx(CIx.TypeOrMethodDef);
		}

		internal override uint SortKey2 ()
		{
			return (uint) index;
		}

		public void AddConstraint  (Type constraint) 
		{
			metadata.AddToTable (MDTable.GenericParamConstraint,
					new GenericParamConstraint (this, constraint));
		}

		internal sealed override uint Size(MetaData md) 
		{
			return (uint) (4 +
					md.CodedIndexSize(CIx.TypeOrMethodDef) + 
					md.StringsIndexSize ());
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(name);
			done = true;
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write ((short) index);
			output.Write ((short) attr);
			output.WriteCodedIndex(CIx.TypeOrMethodDef, owner);
			output.StringsIndex (nameIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 19; 
			}
			return 0;
		}

	}

	internal class GenericParamConstraint : MetaDataElement {

		GenericParameter param;
		Type type;

		public GenericParamConstraint (GenericParameter param, Type type) 
		{
			this.param = param;
			this.type = type;
			tabIx = MDTable.GenericParamConstraint;
		}

		internal override uint SortKey() 
		{
			return param.Row;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return (uint) (md.TableIndexSize(MDTable.GenericParam) +
					md.CodedIndexSize(CIx.TypeDefOrRef));
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteIndex(MDTable.GenericParam, param.Row);
			output.WriteCodedIndex(CIx.TypeDefOrRef, type);
		}

	}

	internal class MethodSpec : Method {

		Method meth;
		GenericMethodSig g_sig;
		uint sidx;

		internal MethodSpec (Method meth, GenericMethodSig g_sig) : base ("")
		{
			this.meth = meth;
			this.g_sig = g_sig;
			tabIx = MDTable.MethodSpec;
		}

		internal override uint GetSigIx (MetaData md)
		{
			throw new Exception ("Should not be used.");
		}

		public override void AddCallConv (CallConv cconv)
		{
			throw new Exception ("Should not be used.");
		}
		
		internal sealed override void BuildTables (MetaData md) 
		{
			if (done) return;
			sidx = g_sig.GetSigIx (md);
			done = true;
		}

		internal sealed override uint Size (MetaData md) 
		{
			return (uint) (md.CodedIndexSize(CIx.MethodDefOrRef) +
					md.BlobIndexSize ());
		}

		internal sealed override void Write (FileImage output) 
		{
			output.WriteCodedIndex (CIx.MethodDefOrRef, meth);
			output.BlobIndex (sidx);
		}

		internal sealed override void TypeSig (MemoryStream sig)
		{
			throw new Exception ("Should not be used.");
		}
	}

	/**************************************************************************/
	/// <summary>
	/// Descriptor for interface implemented by a class
	/// </summary>
	public class InterfaceImpl: MetaDataElement {

		ClassDef theClass;
		Class theInterface;

		internal InterfaceImpl(ClassDef theClass, Class theInterface) 
		{
			this.theClass = theClass;
			this.theInterface = theInterface;
			tabIx = MDTable.InterfaceImpl;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.TableIndexSize(MDTable.TypeDef) + 
				md.CodedIndexSize(CIx.TypeDefOrRef);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteIndex(MDTable.TypeDef,theClass.Row);
			output.WriteCodedIndex(CIx.TypeDefOrRef,theInterface);
		}

		internal sealed override uint GetCodedIx(CIx code) { return 5; }

		internal override uint SortKey ()
		{
			throw new Exception ("Should not be used.");
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for resources used in this PE file 
	/// </summary>

	public class ManifestResource : MetaDataElement {

		public static readonly uint PublicResource = 0x1;
		public static readonly uint PrivateResource = 0x2;

		string mrName;
		MetaDataElement rRef;
		uint fileOffset;
		uint nameIx = 0;
		uint flags = 0;
		byte [] resourceBytes;

		public ManifestResource (string name, byte[] resBytes, uint flags) 
		{
			InitResource (name, flags);
			this.resourceBytes = resBytes;
		}

		public ManifestResource(string name, uint flags, FileRef fileRef) 
		{
			InitResource (name, flags);
			rRef = fileRef;
		}

		public ManifestResource(string name, uint flags, FileRef fileRef, 
				uint fileIx) {
			InitResource (name, flags);
			rRef = fileRef;
			fileOffset = fileIx;
		}

		public ManifestResource(string name, uint flags, AssemblyRef assemRef) 
		{
			InitResource (name, flags);
			rRef = assemRef;
		}

		internal ManifestResource (ManifestResource mres) 
		{
			mrName = mres.mrName;
			flags = mres.flags;
			rRef = mres.rRef;
			fileOffset = mres.fileOffset;
			resourceBytes = mres.resourceBytes;
		}

		private void InitResource (string name, uint flags) 
		{
			mrName = name;
			this.flags = flags;
			tabIx = MDTable.ManifestResource;
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			md.AddToTable (MDTable.ManifestResource, this);
			nameIx = md.AddToStringsHeap(mrName);
			if (resourceBytes != null) {
				if (rRef != null)
					throw new PEFileException ("Manifest Resource has byte value and file reference");
				fileOffset = md.AddResource(resourceBytes);
			} else {
				if (rRef == null)
					throw new PEFileException ("Manifest Resource has no implementation or value");
				rRef.BuildTables (md);
			}

			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 8 + md.StringsIndexSize() + 
				md.CodedIndexSize(CIx.Implementation);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(fileOffset);
			output.Write(flags);
			output.StringsIndex(nameIx);
			output.WriteCodedIndex(CIx.Implementation,rRef);
		}

		internal sealed override uint GetCodedIx(CIx code) { return 18; }

		public string Name {
			get { return mrName; }
			set { mrName = value; }
		}

	}
	/**************************************************************************/  
	/// <summary>
	/// Base class for elements in the PropertyMap, EventMap and 
	/// NestedClass MetaData tables
	/// </summary>
	public class MapElem : MetaDataElement {

		ClassDef parent;
		uint elemIx;
		MDTable elemTable;

		internal MapElem(ClassDef par, uint elIx, MDTable elemTab) 
		{
			parent = par;
			elemIx = elIx;
			elemTable = elemTab;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.TableIndexSize(MDTable.TypeDef) + md.TableIndexSize(elemTable);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteIndex(MDTable.TypeDef,parent.Row);
			output.WriteIndex(elemTable,elemIx);
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for an overriding method (.override)
	/// </summary>
	public class MethodImpl : MetaDataElement {

		ClassDef parent;
		Method header, body;

		internal MethodImpl(ClassDef par, Method decl, Method bod)      
		{
			parent = par;
			header = decl;
			body = bod;
			tabIx = MDTable.MethodImpl;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.TableIndexSize(MDTable.TypeDef) + 2 * md.CodedIndexSize(CIx.MethodDefOrRef);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteIndex(MDTable.TypeDef,parent.Row);
			output.WriteCodedIndex(CIx.MethodDefOrRef,body);
			output.WriteCodedIndex(CIx.MethodDefOrRef,header);
		}

		internal override uint SortKey()
		{
			return parent.Row;
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for Property and Event methods
	/// </summary>
	public class MethodSemantics : MetaDataElement {

		Feature.MethodType type;
		MethodDef meth;
		Feature eventOrProp;

		internal MethodSemantics(Feature.MethodType mType, MethodDef method, Feature feature) 
		{
			type = mType;
			meth = method;
			eventOrProp = feature;
			tabIx = MDTable.MethodSemantics;
		}

		internal override uint SortKey() 
		{
			return (eventOrProp.Row << MetaData.CIxShiftMap [(uint)CIx.HasSemantics])
				| eventOrProp.GetCodedIx (CIx.HasSemantics);
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.TableIndexSize(MDTable.Method) + md.CodedIndexSize(CIx.HasSemantics);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write((ushort)type);
			output.WriteIndex(MDTable.Method,meth.Row);
			output.WriteCodedIndex(CIx.HasSemantics,eventOrProp);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a parameter of a method defined in this assembly/module
	/// </summary>
	public class Param : MetaDataElement {


		Type pType;
		string pName;
		internal ushort seqNo = 0;
		ushort parMode;
		ConstantElem defaultVal;
		uint nameIx = 0;
		FieldMarshal marshalInfo;

		/// <summary>
		/// Create a new parameter for a method
		/// </summary>
		/// <param name="mode">param mode (in, out, opt)</param>
		/// <param name="parName">parameter name</param>
		/// <param name="parType">parameter type</param>
		public Param(ParamAttr mode, string parName, Type parType) 
		{
			pName = parName;
			pType = parType;
			parMode = (ushort)mode;
			tabIx = MDTable.Param;
		}

		public bool HasMarshalInfo {
			get { return marshalInfo != null; }
		}

		/// <summary>
		/// Add a default value to this parameter
		/// </summary>
		/// <param name="c">the default value for the parameter</param>
		public void AddDefaultValue(Constant cVal) 
		{
			defaultVal = new ConstantElem(this,cVal);
			parMode |= (ushort) ParamAttr.HasDefault;
		}

		/// <summary>
		/// Add marshalling information about this parameter
		/// </summary>
		public void AddMarshallInfo(NativeType marshallType) 
		{
			parMode |= (ushort) ParamAttr.HasFieldMarshal;
			marshalInfo = new FieldMarshal(this,marshallType);
		}

		internal Type GetParType() { return pType; }

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(pName);
			if (defaultVal != null) {
				md.AddToTable(MDTable.Constant,defaultVal);
				defaultVal.BuildTables(md);
			}
			if (marshalInfo != null) {
				md.AddToTable(MDTable.FieldMarshal,marshalInfo);
				marshalInfo.BuildTables(md);
			}
			done = true;
		}

		internal void TypeSig(MemoryStream str) 
		{
			pType.TypeSig(str);
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 4 + md.StringsIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(parMode);
			output.Write(seqNo);
			output.StringsIndex(nameIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 4; 
				case (CIx.HasConst) : return 1; 
				case (CIx.HasFieldMarshal) : return 1; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	public abstract class Signature : MetaDataElement  {

		protected uint sigIx;

		internal Signature() 
		{
			tabIx = MDTable.StandAloneSig;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.BlobIndex(sigIx);
		}

		internal sealed override uint GetCodedIx(CIx code) { return (uint)tabIx; }

	}

	/**************************************************************************/  
	public class TypeSpec : MetaDataElement {
		uint sigIx = 0;

		internal TypeSpec(Type aType, MetaData md) 
		{
			MemoryStream sig = new MemoryStream();
			aType.TypeSig(sig);
			sigIx = md.AddToBlobHeap(sig.ToArray());
			tabIx = MDTable.TypeSpec;
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.TypeDefOrRef) : return 2; 
				case (CIx.HasCustomAttr) : return 13; 
				case (CIx.MemberRefParent) : return 4; 
			}
			return 0;
		}

		internal override uint Size(MetaData md) 
		{
			return md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			//Console.WriteLine("Writing the blob index for a TypeSpec");
			output.BlobIndex(sigIx);
		}
	}


	/**************************************************************************/  
	/// <summary>
	/// Base class for all IL types
	/// </summary>
	public abstract class Type : MetaDataElement {
		protected byte typeIndex;
		protected TypeSpec typeSpec;

		internal Type(byte tyIx) { typeIndex = tyIx; }

		internal byte GetTypeIndex() { return typeIndex; }
		internal void SetTypeIndex (byte b) { typeIndex = b; }

		internal virtual MetaDataElement GetTypeSpec(MetaData md) 
		{
			if (typeSpec == null) {
				typeSpec = new TypeSpec(this,md);
				md.AddToTable(MDTable.TypeSpec,typeSpec);
			}
			return typeSpec;
		}

		internal virtual void TypeSig(MemoryStream str) 
		{
			throw(new TypeSignatureException(this.GetType().AssemblyQualifiedName +
						" doesn't have a type signature!!"));   
		}
	}

	public class ClassRefInst : Type {

		private Type type;
		private bool is_value;

		public ClassRefInst (Type type, bool is_value) : base (PrimitiveType.Class.GetTypeIndex ()) 
		{
			this.type = type;
			this.is_value = is_value;
			if (is_value)
				typeIndex = PrimitiveType.ValueType.GetTypeIndex ();
			tabIx = MDTable.TypeSpec;
		}

		internal sealed override void TypeSig(MemoryStream str) 
		{
			type.TypeSig (str);
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// The base descriptor for a class 
	/// </summary>
	public abstract class Class : Type {

		protected int row = 0;
		public string name, nameSpace;
		protected uint nameIx, nameSpaceIx;
		protected MetaData _metaData;
		internal Class(string nameSpaceName, string className, MetaData md)
			: base(PrimitiveType.Class.GetTypeIndex ()) 
		{
				nameSpace = nameSpaceName;
				name = className;
				nameIx = md.AddToStringsHeap(name);
				nameSpaceIx = md.AddToStringsHeap(nameSpace);
				_metaData = md;
		}

		internal Class(uint nsIx, uint nIx) : base(PrimitiveType.Class.GetTypeIndex ()) 
		{
			nameSpaceIx = nsIx;
			nameIx = nIx;
		}

		internal Class (byte typeIndex) : base (typeIndex)
		{
			nameSpace = "Should not be used";
			name = "Should not be used";
		}

		internal virtual uint TypeDefOrRefToken() { return 0; }

		internal virtual void MakeValueClass(ValueClass vClass) 
		{
			typeIndex = PrimitiveType.ValueType.GetTypeIndex ();
		}

		internal virtual string TypeName() 
		{
			return (nameSpace + "." + name);
		}

		internal override MetaDataElement GetTypeSpec(MetaData md) 
		{
			return this;
		}
	}

	/**************************************************************************/  
	// This Class produces entries in the TypeDef table of the MetaData 
	// in the PE meta data.

	// NOTE:  Entry 0 in TypeDef table is always the pseudo class <module> 
	// which is the parent for functions and variables declared a module level

	/// <summary>
	/// The descriptor for a class defined in the IL (.class) in the current assembly/module
	/// </summary>
	/// 
	public class ClassDef : Class {

		Class superType;
		bool setSuperType;
		ArrayList fields = new ArrayList();
		ArrayList methods = new ArrayList();
		ArrayList events;
		ArrayList properties;
		bool typeIndexChecked = true;
		uint fieldIx = 0, methodIx = 0;
		uint flags;
		ClassLayout layout;
		ClassDef parentClass;
		MetaData metaData;

		internal ClassDef(TypeAttr attrSet, string nsName, string name, 
				MetaData md) : base(nsName, name, md) 
		{
			metaData = md;
			flags = (uint)attrSet;
			tabIx = MDTable.TypeDef;
		}

		internal void SetSuper(Class sClass) 
		{
			superType = sClass;
			setSuperType = true;
			if (! (sClass is GenericTypeInst))
				typeIndexChecked = false;
		}

		internal override void MakeValueClass(ValueClass vClass) 
		{
			if (vClass == ValueClass.Enum)  
				superType = metaData.mscorlib.EnumType();
			else  
				superType = metaData.mscorlib.ValueType();

			setSuperType = true;
			typeIndex = PrimitiveType.ValueType.GetTypeIndex ();
		}

		public void SpecialNoSuper() 
		{
			setSuperType = true;
		}

		/// <summary>
		/// Add an attribute to this class
		/// </summary>
		/// <param name="ta">the attribute to be added</param>
		public void AddAttribute(TypeAttr ta) 
		{
			flags |= (uint)ta;
		}

		/// <summary>
		/// Add an interface that is implemented by this class
		/// </summary>
		/// <param name="iFace">the interface that is implemented</param>
		public void AddImplementedInterface(Class iFace) 
		{
			metaData.AddToTable(MDTable.InterfaceImpl,new InterfaceImpl(this,iFace));
		}

		/// <summary>
		///  Add a named generic type parameter
		/// </summary>
		public GenericParameter AddGenericParameter (short index, string name) 
		{
			return AddGenericParameter (index, name, 0);
		}

		/// <summary>
		///  Add a named generic type parameter with attributes
		/// </summary>
		public GenericParameter AddGenericParameter (short index, string name, GenericParamAttributes attr)
		{
			GenericParameter gp = new GenericParameter (this, metaData, index, name, attr);
			metaData.AddToTable (MDTable.GenericParam, gp);
			return gp;
		}

		/// <summary>
		/// Add a field to this class
		/// </summary>
		/// <param name="name">field name</param>
		/// <param name="fType">field type</param>
		/// <returns>a descriptor for this new field</returns>
		public FieldDef AddField(string name, Type fType) 
		{
			FieldDef field = new FieldDef(name,fType);
			fields.Add(field);
			return field;
		}

		/// <summary>
		/// Add a field to this class
		/// </summary>
		/// <param name="fAtts">attributes for this field</param>
		/// <param name="name">field name</param>
		/// <param name="fType">field type</param>
		/// <returns>a descriptor for this new field</returns>
		public FieldDef AddField(FieldAttr fAtts, string name, Type fType) 
		{
			FieldDef field = new FieldDef(fAtts,name,fType);
			fields.Add(field);
			return field;
		}

		public void SetFieldOrder (ArrayList fields)
		{
			this.fields = fields;
		}

		/// <summary>
		/// Add a method to this class
		/// </summary>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">parameters</param>
		/// <returns>a descriptor for this new method</returns>
		public MethodDef AddMethod(string name, Type retType, Param[] pars) 
		{
			return AddMethod (name, new Param (ParamAttr.Default, "", retType), pars);
		}

		public MethodDef AddMethod (string name, Param ret_param, Param [] pars) 
		{
			// Console.WriteLine("Adding method " + name + " to class " + this.name);
			MethodDef meth = new MethodDef(metaData,name, ret_param, pars);
			methods.Add(meth);
			return meth;
		}

		/// <summary>
		/// Add a method to this class
		/// </summary>
		/// <param name="mAtts">attributes for this method</param>
		/// <param name="iAtts">implementation attributes for this method</param>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">parameters</param>
		/// <returns>a descriptor for this new method</returns>
		public MethodDef AddMethod(MethAttr mAtts, ImplAttr iAtts, string name, 
				Param ret_param, Param [] pars) {
			// Console.WriteLine("Adding method " + name + " to class " + this.name);
			MethodDef meth = new MethodDef (metaData, mAtts, iAtts, name, ret_param, pars);
			methods.Add(meth);
			return meth;
		}

		/// <summary>
		/// Add an event to this class
		/// </summary>
		/// <param name="name">event name</param>
		/// <param name="eType">event type</param>
		/// <returns>a descriptor for this new event</returns>
		public Event AddEvent(string name, Type eType) 
		{
			Event e = new Event(name,eType,this);
			if (events == null) events = new ArrayList();
			events.Add(e);
			return e;
		}

		/// <summary>
		/// Add a property to this class
		/// </summary>
		/// <param name="name">property name</param>
		/// <param name="propType">property type</param>
		/// <returns>a descriptor for this new property</returns>
		public Property AddProperty(string name, Type retType, Type[] pars) 
		{
			Property p = new Property(name, retType, pars, this);
			if (properties == null) properties = new ArrayList();
			properties.Add(p);
			return p;
		}

		/// <summary>
		/// Add a nested class to this class
		/// </summary>
		/// <param name="attrSet">attributes for this nested class</param>
		/// <param name="nsName">nested name space name</param>
		/// <param name="name">nested class name</param>
		/// <returns>a descriptor for this new nested class</returns>
		public ClassDef AddNestedClass(TypeAttr attrSet, string nsName, 
				string name) {
			ClassDef nClass = new ClassDef(attrSet,"",name,metaData);
			metaData.AddToTable(MDTable.TypeDef,nClass);
			metaData.AddToTable(MDTable.NestedClass,new MapElem(nClass,Row,MDTable.TypeDef));
			nClass.parentClass = this;
			return (nClass);
		}

		public static bool IsValueType (Class type)
		{
			return IsValueType (type.nameSpace, type.name);
		}

		public static bool IsEnum (Class type)
		{
			return IsEnum (type.nameSpace, type.name);
		}

		public static bool IsValueType (string nsName, string name)
		{
			return (nsName == "System" && name == "ValueType");
		}

		public static bool IsEnum (string nsName, string name)
		{
			return (nsName == "System" && name == "Enum");
		}

		/// <summary>
		/// Add a nested class to this class
		/// </summary>
		/// <param name="attrSet">attributes for this nested class</param>
		/// <param name="nsName">nested name space name</param>
		/// <param name="name">nested class name</param>
		/// <param name="sType">super type of this nested class</param>
		/// <returns>a descriptor for this new nested class</returns>
		public ClassDef AddNestedClass(TypeAttr attrSet, string nsName, 
				string name, Class sType) {
			ClassDef nClass = AddNestedClass (attrSet, nsName, name);
			nClass.SetSuper(sType);
			if (ClassDef.IsValueType (sType))
				nClass.MakeValueClass (ValueClass.ValueType);
			else
				if (ClassDef.IsEnum (sType))
					nClass.MakeValueClass (ValueClass.Enum);

			if (ClassDef.IsValueType (sType) || ClassDef.IsEnum (sType))
				nClass.SetTypeIndex (PrimitiveType.ValueType.GetTypeIndex ());

			nClass.typeIndexChecked = true;
			return (nClass);
		}

		/// <summary>
		/// Add layout information for this class.  This class must have the
		/// sequential or explicit attribute.
		/// </summary>
		/// <param name="packSize">packing size (.pack)</param>
		/// <param name="classSize">class size (.size)</param>
		public void AddLayoutInfo (int packSize, int classSize) 
		{
			layout = new ClassLayout(packSize,classSize,this);
		}

		/// <summary>
		/// Use a method as the implementation for another method (.override)
		/// </summary>
		/// <param name="decl">the method to be overridden</param>
		/// <param name="body">the implementation to be used</param>
		public void AddMethodOverride(Method decl, Method body) 
		{
			metaData.AddToTable(MDTable.MethodImpl,new MethodImpl(this,decl,body));
		}

		/// <summary>
		/// Add security to this class NOT YET IMPLEMENTED
		/// </summary>
		/// <param name="permissionSet"></param>
		public void AddSecurity(byte[] permissionSet) 
		{
			throw(new NotYetImplementedException("Class security "));
			//flags |= HasSecurity;
			// securityActions = permissionSet;
		}

		//public void AddLineInfo(int row, int col) { }

		internal void CheckTypeIndex() 
		{
			if (typeIndexChecked) return;
			if (superType is ClassDef) 
				((ClassDef)superType).CheckTypeIndex();
			typeIndex = superType.GetTypeIndex();
			typeIndexChecked = true;
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) 
				return;
			
			if ((flags & (uint)TypeAttr.Interface) != 0) {
				superType = null;
				setSuperType = true;
			}
			// Console.WriteLine("Building tables for " + name);
			if (layout != null) md.AddToTable(MDTable.ClassLayout,layout);
			// Console.WriteLine("adding methods " + methods.Count);
			methodIx = md.TableIndex(MDTable.Method);
			for (int i=0; i < methods.Count; i++) {
				md.AddToTable(MDTable.Method,(MetaDataElement)methods[i]);
				((MethodDef)methods[i]).BuildTables(md);
			}
			// Console.WriteLine("adding fields");
			fieldIx = md.TableIndex(MDTable.Field);
			for (int i=0; i < fields.Count; i++) {
				md.AddToTable(MDTable.Field,(MetaDataElement)fields[i]);
				((FieldDef)fields[i]).BuildTables(md);
			}
			// Console.WriteLine("adding events and properties");
			if (events != null) { 
				for (int i=0; i < events.Count; i++) {
					md.AddToTable(MDTable.Event,(Event)events[i]);
					((Event)events[i]).BuildTables(md);
				}
				md.AddToTable(MDTable.EventMap,
						new MapElem(this,((Event)events[0]).Row,MDTable.Event));
			}
			if (properties != null) { 
				for (int i=0; i < properties.Count; i++) {
					md.AddToTable(MDTable.Property,(Property)properties[i]);
					((Property)properties[i]).BuildTables(md);
				}
				md.AddToTable(MDTable.PropertyMap,new MapElem(this,
							((Property)properties[0]).Row,MDTable.Property));
			}
			// Console.WriteLine("End of building tables");

			if (!setSuperType)
				superType = metaData.mscorlib.GetSpecialSystemClass(PrimitiveType.Object);

			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 4 + 2 * md.StringsIndexSize() + 
				md.CodedIndexSize(CIx.TypeDefOrRef) +
				md.TableIndexSize(MDTable.Field) + 
				md.TableIndexSize(MDTable.Method);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.StringsIndex(nameIx);
			output.StringsIndex(nameSpaceIx);
			//if (superType != null) 
			// Console.WriteLine("getting coded index for superType of " + name + " = " + superType.GetCodedIx(CIx.TypeDefOrRef));
			output.WriteCodedIndex(CIx.TypeDefOrRef,superType);
			output.WriteIndex(MDTable.Field,fieldIx);
			output.WriteIndex(MDTable.Method,methodIx);
		}

		internal sealed override uint TypeDefOrRefToken() 
		{
			uint cIx = Row;
			cIx = cIx << 2;
			return cIx;
		}

		internal sealed override void TypeSig(MemoryStream sig) 
		{
			if (!typeIndexChecked) CheckTypeIndex();
			sig.WriteByte(GetTypeIndex());
			MetaData.CompressNum(TypeDefOrRefToken(),sig);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.TypeDefOrRef) : return 0; 
				case (CIx.HasCustomAttr) : return 3; 
				case (CIx.HasDeclSecurity) : return 0; 
				case (CIx.TypeOrMethodDef) : return 0; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a class/interface declared in another module of THIS 
	/// assembly, or in another assembly.
	/// </summary>
	public class ClassRef : Class, IExternRef, IResolutionScope {

		protected IResolutionScope parent;
		protected MetaData metaData;

		internal ClassRef(string nsName, string name, MetaData md) : base(nsName, name, md) 
		{
			metaData = md;
			tabIx = MDTable.TypeRef;
		}

		/// <summary>
		/// Add a method to this class
		/// </summary>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">parameter types</param>
		/// <returns>a descriptor for this method</returns>
		public MethodRef AddMethod(string name, Type retType, Type[] pars) 
		{
			return AddMethod (name, retType, pars, 0);
		}
		
		/// <summary>
		/// Add a method to this class
		/// </summary>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">parameter types</param>
		/// <param name="gen_param_count">num of generic parameters</param>
		/// <returns>a descriptor for this method</returns>
		public MethodRef AddMethod (string name, Type retType, Type[] pars, int gen_param_count) 
		{
			MethodRef meth = new MethodRef (this, name, retType, pars, false, null, gen_param_count);
			metaData.AddToTable(MDTable.MemberRef,meth);
			return meth;
		}

		/// <summary>
		/// Add a method to this class
		/// </summary>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">parameter types</param>
		/// <returns>a descriptor for this method</returns>
		public MethodRef AddVarArgMethod(string name, Type retType, 
				Type[] pars, Type[] optPars) 
		{
			MethodRef meth = new MethodRef(this,name,retType,pars,true,optPars, 0);
			metaData.AddToTable(MDTable.MemberRef,meth);
			return meth;
		}

		/// <summary>
		/// Add a field to this class
		/// </summary>
		/// <param name="name">field name</param>
		/// <param name="fType">field type</param>
		/// <returns>a descriptor for this field</returns>
		public FieldRef AddField(string name, Type fType) 
		{
			FieldRef field = new FieldRef(this,name,fType);
			metaData.AddToTable(MDTable.MemberRef,field);
			return field;
		}

		public ClassRef AddClass (string nsName, string name)
		{
			ClassRef aClass = new ClassRef(nsName,name,metaData);
			metaData.AddToTable(MDTable.TypeRef,aClass);
			aClass.SetParent(this);
			return aClass;
		}

		public ClassRef AddValueClass (string nsName, string name)
		{
			ClassRef aClass = AddClass (nsName, name);
			aClass.MakeValueClass (ValueClass.ValueType);
			return aClass;
		}

		internal void SetParent(IResolutionScope par) 
		{
			parent = par;
		}

		internal override string TypeName() 
		{
			if ((parent != null) && (parent is AssemblyRef))
				return (nameSpace + "." + name + ", " + ((AssemblyRef)parent).TypeName());
			else 
				return (nameSpace + name);
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.CodedIndexSize(CIx.ResolutionScope) + 2 * 
				md.StringsIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteCodedIndex(CIx.ResolutionScope,(MetaDataElement) parent);
			output.StringsIndex(nameIx);
			output.StringsIndex(nameSpaceIx);
		}

		internal override sealed uint TypeDefOrRefToken() 
		{
			uint cIx = Row;
			cIx = (cIx << 2) | 0x1;
			return cIx;
		}

		internal override void TypeSig(MemoryStream sig) 
		{
			sig.WriteByte(GetTypeIndex());
			MetaData.CompressNum(TypeDefOrRefToken(),sig);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.TypeDefOrRef) : return 1; 
				case (CIx.HasCustomAttr) : return 2; 
				case (CIx.MemberRefParent) : return 1; 
				case (CIx.ResolutionScope) : return 3; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	public class ExternClassRef : ClassRef {

		ExternClass externClass;

		internal ExternClassRef(TypeAttr attrs, string nsName, string name,
				MetaDataElement declRef, MetaData md) : base(nsName,name,md) 
		{
			externClass = new ExternClass(attrs,nameSpaceIx,nameIx,declRef);
			metaData.AddToTable(MDTable.ExportedType,externClass);
		}

		internal ExternClassRef(string name, MetaData md) : base(null,name,md) 
		{
		}

		public ClassRef AddNestedClass(TypeAttr attrs, string name) 
		{
			ExternClassRef nestedClass = new ExternClassRef(name,metaData);
			externClass = new ExternClass(attrs,0,nameIx,this.externClass);
			metaData.AddToTable(MDTable.ExportedType,externClass);
			return nestedClass;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a class defined in another module of THIS assembly 
	/// and exported (.class extern)
	/// </summary>

	internal class ExternClass : Class {

		MetaDataElement parent;
		uint flags;

		internal ExternClass(TypeAttr attr, uint nsIx, uint nIx, 
				MetaDataElement paren) : base(nsIx,nIx) 
		{
			flags = (uint)attr;
			parent = paren;
			tabIx = MDTable.ExportedType;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 8 + 2* md.StringsIndexSize() + md.CodedIndexSize(CIx.Implementation);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.Write(0);
			output.StringsIndex(nameIx);
			output.StringsIndex(nameSpaceIx);
			output.WriteCodedIndex(CIx.Implementation,parent);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 17; 
				case (CIx.Implementation) : return 2; 
			}
			return 0;
		}

	}

	public class GenParam : Class {

		private int index;
		private string param_name;
		private uint sigIx = 0;

		public GenParam (int index, string name, GenParamType ptype) : base ((byte) ptype) 
		{
			this.index = index;
			this.param_name = name;
			tabIx = MDTable.TypeSpec;
		}

		public int Index {
			get { return index; }
			set { index = value; }
		}

		public string Name {
			get { return param_name; }
			set { param_name = value; }
		}

		public GenParamType Type {
			get { return (GenParamType) GetTypeIndex (); }
		}
		
		internal sealed override void BuildTables (MetaData md)
		{
			if (done)
				return;
			MemoryStream str = new MemoryStream ();
			TypeSig (str);
			sigIx = md.AddToBlobHeap (str.ToArray ());

			done = true;
		}

		internal sealed override void TypeSig(MemoryStream str) 
		{
			if (index < 0)
				throw new PEFileException (String.Format ("Unresolved {0} - {1}", (GenParamType) GetTypeIndex (), param_name));
			str.WriteByte(typeIndex);
			MetaData.CompressNum ((uint) index, str);
		}
		
		internal override uint Size(MetaData md) 
		{
			return md.BlobIndexSize();
		}

		internal sealed override void Write (FileImage output)
		{
			output.BlobIndex (sigIx);	
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.TypeDefOrRef) : return 2; 
				case (CIx.HasCustomAttr) : return 13; 
				case (CIx.MemberRefParent) : return 4; 
			}
			return 0;
		}
	}

	public class GenericTypeInst : Class {

		private Type gen_type;
		private Type[] gen_param;
		bool inTable = false;
		uint sigIx = 0;

		public GenericTypeInst (Type gen_type, Type[] gen_param) 
			: base ((byte) PrimitiveType.GenericInst.GetTypeIndex ())
		{
			this.gen_type = gen_type;
			this.gen_param = gen_param;
			tabIx = MDTable.TypeSpec;
		}

		internal override MetaDataElement GetTypeSpec (MetaData md)
		{
			if (!inTable) {
				md.AddToTable (MDTable.TypeSpec, this);
				inTable = true;
			}

			return this;
		}

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);
			gen_type.TypeSig (str);
			MetaData.CompressNum ((uint) gen_param.Length, str);
			foreach (Type param in gen_param)
				param.TypeSig (str);
		}

		internal sealed override void BuildTables (MetaData md)
		{
			if (done)
				return;
			MemoryStream str = new MemoryStream ();
			TypeSig (str);
			sigIx = md.AddToBlobHeap (str.ToArray ());

			done = true;
		}

		internal sealed override uint Size (MetaData md)
		{
			return md.BlobIndexSize ();
		}

		internal sealed override void Write (FileImage output)
		{
			output.BlobIndex (sigIx);	
		}

		internal sealed override uint GetCodedIx (CIx code)
		{
			switch (code) {
				case (CIx.TypeDefOrRef): return 2;
				case (CIx.MemberRefParent): return 4;
				case (CIx.HasCustomAttr): return 13;
			}
			return 0;
		}
	}

	public class GenericMethodSig {

		private Type[] gen_param;
		private bool done;
		private uint sigIx = 0;

		public GenericMethodSig (Type[] gen_param)
		{
			this.gen_param = gen_param;
			done = false;
		}

		internal void TypeSig (MemoryStream str)
		{
			str.WriteByte (0x0A); /* GENERIC_INST */
			MetaData.CompressNum ((uint) gen_param.Length, str);
			foreach (Type param in gen_param)
				param.TypeSig (str);
		}

		internal uint GetSigIx (MetaData md)
		{
			if (done)
				return sigIx;

			MemoryStream sig = new MemoryStream();
			TypeSig (sig);
			sigIx = md.AddToBlobHeap (sig.ToArray());
			done = true;
			return sigIx;
		}
	}

	public class Sentinel : Type {

		public Sentinel () : base (0x41) { }

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a FunctionPointer type
	/// </summary>
	/// 
	public class MethPtrType : Type {

		bool varArgMeth;
		Type retType;
		Type [] parList;
		Type [] optParList;
		CallConv callConv;
		uint numPars;
		uint numOptPars;
		uint sigIx = 0;

		/// <summary>
		/// Create a new function pointer type
		/// </summary>
		/// <param name="meth">the function to be referenced</param>
		public MethPtrType (CallConv callconv, Type retType, Type[] pars,
				bool varArgMeth, Type[] optPars) : base(0x1B) 
		{
			this.retType = retType;
			callConv = callconv;
			parList = pars;
			this.varArgMeth = varArgMeth;
			if (parList != null) numPars = (uint)parList.Length;
			if (varArgMeth) {
				optParList = optPars;
				if (optParList != null) numOptPars = (uint)optParList.Length;
				callConv |= CallConv.Vararg;
			}
			tabIx = MDTable.TypeSpec;
		}

		internal sealed override void TypeSig(MemoryStream sig) 
		{
			sig.WriteByte(typeIndex);
			// Bootlegged from method ref
			sig.WriteByte((byte)callConv);
			MetaData.CompressNum (numPars + numOptPars, sig);
			retType.TypeSig (sig);
			for (int i=0; i < numPars; i++) {
				parList[i].TypeSig (sig);
			}
			if (varArgMeth) {
				sig.WriteByte (0x41); // Write the sentinel
				for (int i=0; i < numOptPars; i++) {
					optParList[i].TypeSig (sig);
				}
			}
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			MemoryStream sig = new MemoryStream();
			TypeSig(sig);
			sigIx = md.AddToBlobHeap(sig.ToArray());
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.BlobIndex(sigIx);
		}

		internal sealed override uint GetCodedIx(CIx code) { return 0x1B; }

	}

	#region Array Types
	/* Classes for Arrays */

	/// <summary>
	/// The IL Array type
	/// </summary>
	public abstract class Array : Type {

		protected Type elemType;
		protected MetaData metaData;
		protected string cnameSpace, cname;

		internal Array(Type eType, byte TypeId) : base(TypeId) 
		{
			elemType = eType;
			tabIx = MDTable.TypeSpec;
		}
	}

	/// <summary>
	/// Single dimensional array with zero lower bound
	/// </summary>
	public class ZeroBasedArray : Array {

		/// <summary>
		/// Create a new array  -   elementType[]
		/// </summary>
		/// <param name="elementType">the type of the array elements</param>
		public ZeroBasedArray(Type elementType) : base (elementType, PrimitiveType.SZArray.GetTypeIndex ()) { }

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);
			elemType.TypeSig(str); 
		}

	}

	/// <summary>
	/// Multi dimensional array with explicit bounds
	/// </summary>
	public class BoundArray : Array {
		int[] lowerBounds;
		int[] sizes;
		uint numDims;

		/// <summary>
		/// Create a new multi dimensional array type 
		/// eg. elemType[1..5,3..10,5,,] would be 
		/// new BoundArray(elemType,5,[1,3,0],[5,10,4])
		/// </summary>
		/// <param name="elementType">the type of the elements</param>
		/// <param name="dimensions">the number of dimensions</param>
		/// <param name="loBounds">lower bounds of dimensions</param>
		/// <param name="sizes">sizes for the dimensions</param>
		public BoundArray(Type elementType, uint dimensions, int[] loBounds, 
				int[] sizes) : base (elementType,0x14) 
		{
			numDims = dimensions;
			lowerBounds = loBounds;
			this.sizes = sizes;
		}

		/// <summary>
		/// Create a new multi dimensional array type 
		/// eg. elemType[5,10,20] would be new BoundArray(elemType,3,[5,10,20])
		/// </summary>
		/// <param name="elementType">the type of the elements</param>
		/// <param name="dimensions">the number of dimensions</param>
		/// <param name="size">the sizes of the dimensions</param>
		public BoundArray(Type elementType, uint dimensions, int[] size) 
			: base (elementType,0x14) 
		{
			numDims = dimensions;
			sizes = size;
		}

		/// <summary>
		/// Create a new multi dimensional array type 
		/// eg. elemType[,,] would be new BoundArray(elemType,3)
		/// </summary>
		/// <param name="elementType">the type of the elements</param>
		/// <param name="dimensions">the number of dimensions</param>
		public BoundArray(Type elementType, uint dimensions)
			: base (elementType,0x14) 
		{
			numDims = dimensions;
		}

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);
			elemType.TypeSig(str);
			MetaData.CompressNum(numDims,str);
			if ((sizes != null) && (sizes.Length > 0))  {

				MetaData.CompressNum((uint)sizes.Length,str);
				for (int i=0; i < sizes.Length; i++) {
					MetaData.CompressNum((uint)sizes[i],str);
				}
			} else str.WriteByte(0);
			if ((lowerBounds != null) && (lowerBounds.Length > 0)) {
				MetaData.CompressNum((uint)lowerBounds.Length,str);
				for (int i=0; i < lowerBounds.Length; i++) {
					CompressSignedNum (lowerBounds[i],str);
				}
			} else str.WriteByte(0);
		}
		private void CompressSignedNum (int val, MemoryStream str)
		{
			uint uval = (uint) val;
			byte sign = 0;
			if (val < 0) {
				val = -val;
				sign = 1;
			}

			/* Map the signed number to an unsigned number in two ways.

			     fval: left-rotated 2's complement representation
			     sval: map the signed number to unsigned as follows: 0 -> 0, -1 -> 1, 1 -> 2, -2 -> 3, 2 -> 4, ....
			           the mapping is: x -> 2*|x| - signbit(x)
			*/
			uint fval = (uval << 1) | sign;
			int sval = (val  << 1) - sign;

			/* An overly clever transformation: 

			   a. sval is used to determine the number of bytes in the compressed representation.
			   b. fval is truncated to the appropriate number of bits and output using the 
			      normal unsigned-int compressor.

			   However, or certain values, the truncated fval doesn't carry enough information to round trip.

				(fval & 0x3FFF) <= 0x7F => compressor emits 1 byte, not 2 => there is aliasing of values

			   So, we use full 4 bytes to encode such values.

			   LAMESPEC: The Microsoft implementation doesn't appear to handle this subtle case.
			   	     e.g., it ends up encoding -8192 as the byte 0x01, which decodes to -64
			*/
			if (sval <= 0x7F)
				MetaData.CompressNum (fval & 0x7F, str);
			else if (sval <= 0x3FFF && (fval & 0x3FFF) > 0x7F)
				MetaData.CompressNum (fval & 0x3FFF, str);
			else if (sval <= 0x1FFFFFFF && (fval & 0x1FFFFFFF) > 0x3FFF)
				MetaData.CompressNum (fval & 0x1FFFFFFF, str);
			else
				/* FIXME: number cannot be represented.  Report a warning.  */
				// throw new Exception ("cannot represent signed value" + -val);
				MetaData.CompressNum (fval, str);
		}
	}

	#endregion


	/* Empty interface for grouping TypeRef's possible ResolutionScope
	   namely : Module, ModuleRef, AssemblyRef and TypeRef */
	public interface IResolutionScope  {
	}

	/**************************************************************************/  
	/// <summary>
	/// Base class for scopes (extended by Module, ModuleRef, Assembly, AssemblyRef)
	/// </summary>
	public abstract class ResolutionScope : MetaDataElement, IResolutionScope {

		protected uint nameIx = 0;
		protected MetaData metaData;
		protected string name;

		internal ResolutionScope(string name, MetaData md)
		{
			metaData = md;
			this.name = name;
			nameIx = md.AddToStringsHeap(name);
		}

		internal string GetName() { return name; }

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for THIS assembly (.assembly)
	/// </summary>
	public class Assembly : ResolutionScope  {

		ushort majorVer, minorVer, buildNo, revisionNo;
		uint flags;
		uint hashAlgId;
		uint keyIx = 0, cultIx = 0;
		bool hasPublicKey = false;

		internal Assembly(string name, MetaData md) : base(name,md) 
		{
			tabIx = MDTable.Assembly;
		}

		/// <summary>
		/// Add details about THIS assembly
		/// </summary>
		/// <param name="majVer">Major Version</param>
		/// <param name="minVer">Minor Version</param>
		/// <param name="bldNo">Build Number</param>
		/// <param name="revNo">Revision Number</param>
		/// <param name="key">Hash Key</param>
		/// <param name="hash">Hash Algorithm</param>
		/// <param name="cult">Culture</param>
		public void AddAssemblyInfo(int majVer, int minVer, int bldNo, int revNo, 
				byte[] key, uint hash, string cult) 
		{
			majorVer = (ushort)majVer;
			minorVer = (ushort)minVer;
			buildNo = (ushort)bldNo;
			revisionNo = (ushort)revNo;
			hashAlgId = hash;
			hasPublicKey = (key != null);
			keyIx = metaData.AddToBlobHeap(key);
			cultIx = metaData.AddToStringsHeap(cult);
		}

		/// <summary>
		/// Add an attribute to THIS assembly
		/// </summary>
		/// <param name="aa">assembly attribute</param>
		public void AddAssemblyAttr(AssemAttr aa) 
		{
			flags |= (uint)aa;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 16 + md.BlobIndexSize() + 2 * md.StringsIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			//      Console.WriteLine("Writing assembly element with nameIx of " + nameIx + " at file offset " + output.Seek(0,SeekOrigin.Current));
			output.Write((uint)hashAlgId);
			output.Write(majorVer);
			output.Write(minorVer);
			output.Write(buildNo);
			output.Write(revisionNo);
			output.Write(flags);
			output.BlobIndex(keyIx);
			output.StringsIndex(nameIx);
			output.StringsIndex(cultIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 14; 
				case (CIx.HasDeclSecurity) : return 2; 
			}
			return 0;
		}

		internal bool HasPublicKey {
			get { return hasPublicKey; }
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for THIS module
	/// </summary>
	public class Module : ResolutionScope, IExternRef {

		Guid mvid;
		uint mvidIx = 0;

		internal Module(string name, MetaData md) : base(name,md)       
		{
			mvid = Guid.NewGuid();
			mvidIx = md.AddToGUIDHeap(mvid);
			tabIx = MDTable.Module;
		}

		public Guid Guid {
			get { return mvid; }
		}

		public ClassRef AddClass(string nsName, string name) 
		{
			ClassRef aClass = new ClassRef (nsName, name, metaData);
			metaData.AddToTable (MDTable.TypeRef, aClass);
			aClass.SetParent (this);
			return aClass;
		}

		public ClassRef AddValueClass(string nsName, string name) 
		{
			ClassRef aClass = AddClass (nsName, name);
			aClass.MakeValueClass (ValueClass.ValueType);
			return aClass;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.StringsIndexSize() + 3 * md.GUIDIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write((short)0);
			output.StringsIndex(nameIx);
			output.GUIDIndex(mvidIx);
			output.GUIDIndex(0);
			output.GUIDIndex(0);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 7; 
				case (CIx.ResolutionScope) : return 0;
			}
			return 0;
		}
	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for another module in THIS assembly
	/// </summary>
	public class ModuleRef : ResolutionScope, IExternRef {

		internal ModuleRef(MetaData md, string name) : base(name,md) 
		{
			tabIx = MDTable.ModuleRef;
		}

		/// <summary>
		/// Add a class to this external module.  This is a class declared in
		/// another module of THIS assembly.
		/// </summary>
		/// <param name="nsName">name space name</param>
		/// <param name="name">class name</param>
		/// <returns>a descriptor for this class in another module</returns>
		public ClassRef AddClass(string nsName, string name) 
		{
			ClassRef aClass = new ClassRef(nsName,name,metaData);
			metaData.AddToTable(MDTable.TypeRef,aClass);
			aClass.SetParent(this);
			return aClass;
		}

		/// <summary>
		/// Make a file descriptor to correspond to this module.  The file
		/// descriptor will have the same name as the module descriptor
		/// </summary>
		/// <param name="hashBytes">the hash of the file</param>
		/// <param name="hasMetaData">the file contains metadata</param>
		/// <param name="entryPoint">the program entry point is in this file</param>
		/// <returns>a descriptor for the file which contains this module</returns>
		public FileRef MakeFile(byte[] hashBytes, bool hasMetaData, bool entryPoint) 
		{
			FileRef file = new FileRef(nameIx,hashBytes,hasMetaData,entryPoint,metaData);
			metaData.AddToTable(MDTable.File,file);
			return file;
		}

		/// <summary>
		/// Add a value class to this module.  This is a class declared in
		/// another module of THIS assembly.
		/// </summary>
		/// <param name="nsName">name space name</param>
		/// <param name="name">class name</param>
		/// <returns></returns>
		public ClassRef AddValueClass(string nsName, string name) 
		{
			ClassRef aClass = new ClassRef(nsName,name,metaData);
			metaData.AddToTable(MDTable.TypeRef,aClass);
			aClass.SetParent(this);
			aClass.MakeValueClass(ValueClass.ValueType);
			return aClass;
		}

		/// <summary>
		/// Add a class which is declared public in this external module of
		/// THIS assembly.  This class will be exported from this assembly.
		/// The ilasm syntax for this is .extern class
		/// </summary>
		/// <param name="attrSet">attributes of the class to be exported</param>
		/// <param name="nsName">name space name</param>
		/// <param name="name">external class name</param>
		/// <param name="declFile">the file where the class is declared</param>
		/// <param name="isValueClass">is this class a value type?</param>
		/// <returns>a descriptor for this external class</returns>
		public ExternClassRef AddExternClass(TypeAttr attrSet, string nsName, 
				string name, FileRef declFile, 
				bool isValueClass) {
			ExternClassRef cRef = new ExternClassRef(attrSet,nsName,name,declFile,metaData);
			metaData.AddToTable(MDTable.TypeRef,cRef);
			cRef.SetParent(this);
			if (isValueClass) cRef.MakeValueClass(ValueClass.ValueType);
			return cRef;
		}

		/// <summary>
		/// Add a "global" method in another module
		/// </summary>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">method parameter types</param>
		/// <returns>a descriptor for this method in anther module</returns>
		public MethodRef AddMethod(string name, Type retType, Type[] pars) 
		{
			MethodRef meth = new MethodRef(this,name,retType,pars,false,null, 0);
			metaData.AddToTable(MDTable.MemberRef,meth);
			return meth;
		}

		/// <summary>
		/// Add a vararg method to this class
		/// </summary>
		/// <param name="name">method name</param>
		/// <param name="retType">return type</param>
		/// <param name="pars">parameter types</param>
		/// <param name="optPars">optional param types for this vararg method</param>
		/// <returns>a descriptor for this method</returns>
		public MethodRef AddVarArgMethod(string name, Type retType, 
				Type[] pars, Type[] optPars) {
			MethodRef meth = new MethodRef(this,name,retType,pars,true,optPars, 0);
			metaData.AddToTable(MDTable.MemberRef,meth);
			return meth;
		}

		/// <summary>
		/// Add a field in another module
		/// </summary>
		/// <param name="name">field name</param>
		/// <param name="fType">field type</param>
		/// <returns>a descriptor for this field in another module</returns>
		public FieldRef AddField(string name, Type fType) 
		{
			FieldRef field = new FieldRef(this,name,fType);
			metaData.AddToTable(MDTable.MemberRef,field);
			return field;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.StringsIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.StringsIndex(nameIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 12; 
				case (CIx.MemberRefParent) : return 2; 
				case (CIx.ResolutionScope) : return 1; 
			}
			return 0;
		}

	}

	#region Classes for Constants
	/// <summary>
	/// Descriptor for a constant value
	/// </summary>
	public abstract class Constant {
		protected uint size = 0;
		protected Type type;
		protected uint blobIndex;
		protected bool addedToBlobHeap = false;

		internal Constant() { }

		internal virtual uint GetBlobIndex(MetaData md) { return 0; }

		internal uint GetSize() { return size; }

		internal byte GetTypeIndex() { return type.GetTypeIndex(); }

		internal virtual void Write(BinaryWriter bw) {  }

	}
	/// <summary>
	/// Descriptor for a constant value
	/// </summary>
	public abstract class DataConstant : Constant {
		private uint dataOffset = 0;

		internal DataConstant() { }

		public uint DataOffset {
			get { return dataOffset; }
			set { dataOffset = value; }
		}

	}

	/// <summary>
	/// Boolean constant
	/// </summary>
	public class BoolConst : DataConstant {
		bool val;

		/// <summary>
		/// Create a new boolean constant with the value "val"
		/// </summary>
		/// <param name="val">value of this boolean constant</param>
		public BoolConst(bool val) 
		{
			this.val = val;
			size = 1;
			type = PrimitiveType.Boolean;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				if (val) blobIndex = md.AddToBlobHeap((sbyte)1);
				else blobIndex = md.AddToBlobHeap((sbyte)0);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			if (val) bw.Write((sbyte)1);
			else bw.Write((sbyte)0);
		}

	}

	public class ByteArrConst : DataConstant {
		internal byte[] val;

		public ByteArrConst(byte[] val) 
		{
			type = PrimitiveType.String;
			this.val = val;
			size = (uint)val.Length;
		}

		public Type Type {
			get { return type; }
			set { type = value; }
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				blobIndex = md.AddToBlobHeap(val);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			bw.Write(val);
		}

	}

	public class CharConst : Constant {
		char val;

		public CharConst(char val) 
		{
			this.val = val;
			size = 2;
			type = PrimitiveType.Char;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				blobIndex = md.AddToBlobHeap(val);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			bw.Write(val);
		}

	}

	public class FloatConst : DataConstant {
		float val;

		public FloatConst(float val) 
		{
			this.val = val;
			size = 4;
			type = PrimitiveType.Float32;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				blobIndex = md.AddToBlobHeap(val);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			bw.Write(val);
		}

	}

	public class DoubleConst : DataConstant {
		double val;

		public DoubleConst(double val) 
		{
			this.val = val;
			size = 8;
			type = PrimitiveType.Float64;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				blobIndex = md.AddToBlobHeap(val);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			bw.Write(val);
		}

	}

	public class IntConst : DataConstant {
		long val;

		public IntConst(sbyte val) 
		{
			this.val = val;
			size = 1;
			type = PrimitiveType.Int8;
		}

		public IntConst(short val) 
		{
			this.val = val;
			size = 2;
			type = PrimitiveType.Int16;
		}

		public IntConst(int val) 
		{
			this.val = val;
			size = 4;
			type = PrimitiveType.Int32;
		}

		public IntConst(long val) 
		{
			this.val = val;
			size = 8;
			type = PrimitiveType.Int64;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				switch (size) {
					case (1) : blobIndex = md.AddToBlobHeap((sbyte)val); break;
					case (2) : blobIndex = md.AddToBlobHeap((short)val); break;
					case (4) : blobIndex = md.AddToBlobHeap((int)val); break;
					default : blobIndex = md.AddToBlobHeap(val); break; 
				}
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			switch (size) {
				case (1) : bw.Write((sbyte)val); break;
				case (2) : bw.Write((short)val); break;
				case (4) : bw.Write((int)val); break;
				default : bw.Write(val); break; 
			}
		}

	}

	public class UIntConst : DataConstant {
		ulong val;

		public UIntConst(byte val) 
		{
			this.val = val;
			size = 1;
			type = PrimitiveType.UInt8;
		}
		public UIntConst(ushort val) 
		{
			this.val = val;
			size = 2;
			type = PrimitiveType.UInt16;
		}
		public UIntConst(uint val) 
		{
			this.val = val;
			size = 4;
			type = PrimitiveType.UInt32;
		}
		public UIntConst(ulong val) 
		{
			this.val = val;
			size = 8;
			type = PrimitiveType.UInt64;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				switch (size) {
					case (1) : blobIndex = md.AddToBlobHeap((byte)val); break;
					case (2) : blobIndex = md.AddToBlobHeap((ushort)val); break;
					case (4) : blobIndex = md.AddToBlobHeap((uint)val); break;
					default : blobIndex = md.AddToBlobHeap(val); break;
				}
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			switch (size) {
				case (1) : bw.Write((byte)val); break;
				case (2) : bw.Write((ushort)val); break;
				case (4) : bw.Write((uint)val); break;
				default : bw.Write(val); break;
			}
		}

	}

	public class StringConst : DataConstant {
		internal string val;

		public StringConst(string val) 
		{
			this.val = val;
			size = (uint)val.Length;  // need to add null ??
			type = PrimitiveType.String;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				byte [] b = Encoding.Unicode.GetBytes (val);
				blobIndex = md.AddToBlobHeap(b);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			bw.Write(val);
		}

	}

	public class NullConst : Constant {

		public NullConst() 
		{
			size = 4;
			type = PrimitiveType.Class;
		}

		internal sealed override uint GetBlobIndex(MetaData md) 
		{
			if (!addedToBlobHeap) {
				blobIndex = md.AddToBlobHeap((int)0);
				addedToBlobHeap = true;
			}
			return blobIndex;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			bw.Write((int)0); 
		}

	}

	public class AddressConstant : DataConstant {
		DataConstant data;

		public AddressConstant(DataConstant dConst) 
		{
			data = dConst;
			size = 4;
			type = PrimitiveType.TypedRef;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			((FileImage)bw).WriteDataRVA(data.DataOffset);
		}

	}

	public class RepeatedConstant : DataConstant {
		DataConstant data;
		uint repCount;

		public RepeatedConstant(DataConstant dConst, int repeatCount) 
		{
			data = dConst;
			repCount = (uint)repeatCount;
			int[] sizes = new int[1];
			sizes[0] = repeatCount;
			type = new BoundArray(type,1,sizes);
			size = data.GetSize() * repCount;
		}

		internal sealed override void Write(BinaryWriter bw) 
		{
			for (int i=0; i < repCount; i++) {
				data.Write(bw);
			}
		}

	}

	public class ArrayConstant : DataConstant {
		DataConstant[] dataVals;

		public ArrayConstant(DataConstant[] dVals) 
		{
			dataVals = dVals;
			for (int i=0; i < dataVals.Length; i++) {
				size += dataVals[i].GetSize();
			}
		}

		public int? ExplicitSize { get; set; }

		internal sealed override void Write(BinaryWriter bw) 
		{
			for (int i=0; i < dataVals.Length; i++) {
				dataVals[i].Write(bw);
			}
		}

	}

	public class ClassType : Constant {
		string name;
		Class desc;

		public ClassType(string className) 
		{
			name = className;
			type = PrimitiveType.ClassType;
		}

		public ClassType(Class classDesc) 
		{
			desc = classDesc;
			type = PrimitiveType.ClassType;
		}

		internal override void Write(BinaryWriter bw) 
		{
			if (name == null)  name = desc.TypeName();
			bw.Write(name);
		}

	}

	#endregion

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a custom modifier of a type (modopt or modreq)
	/// </summary>

	public class CustomModifiedType : Type {

		Type type;
		Class cmodType;
		PrimitiveTypeRef cmodPrimType;

		/// <summary>
		/// Create a new custom modifier for a type
		/// </summary>
		/// <param name="type">the type to be modified</param>
		/// <param name="cmod">the modifier</param>
		/// <param name="cmodType">the type reference to be associated with the type</param>
		public CustomModifiedType(Type type, CustomModifier cmod, Class cmodType)
			: base((byte)cmod) 
		{
			this.type = type;
			this.cmodType = cmodType;
		}

		public CustomModifiedType(Type type, CustomModifier cmod, PrimitiveTypeRef cmodType)
			: base((byte)cmod)
		{
			this.type = type;
			this.cmodPrimType = cmodType;
		}

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);

			if (cmodType != null) {
				MetaData.CompressNum(cmodType.TypeDefOrRefToken(),str);
			} else {
				MetaData.CompressNum(cmodPrimType.TypeDefOrRefToken(),str);
			}

			type.TypeSig(str);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Base class for Event and Property descriptors
	/// </summary>

	public class Feature : MetaDataElement {

		internal enum MethodType : ushort { Setter = 0x01, Getter, Other = 0x04, AddOn = 0x08, 
			RemoveOn = 0x10, Fire = 0x20 }

		private static readonly int INITSIZE = 5;
		private static readonly ushort specialName = 0x200;
		private static readonly ushort rtSpecialName = 0x400;

		protected ClassDef parent;
		protected ushort flags = 0;
		protected string name;
		protected int tide = 0;
		protected uint nameIx;
		protected MethodSemantics[] methods = new MethodSemantics[INITSIZE];

		internal Feature(string name, ClassDef par) 
		{
			parent = par;
			this.name = name;
		}

		internal void AddMethod(MethodDef meth, MethodType mType) 
		{
			if (tide >= methods.Length) { 
				int len = methods.Length;
				MethodSemantics[] mTmp = methods;
				methods = new MethodSemantics[len * 2];
				for (int i=0; i < len; i++) {
					methods[i] = mTmp[i];
				}
			}
			methods[tide++] = new MethodSemantics(mType,meth,this);
		}

		/// <summary>
		/// Set the specialName attribute for this Event or Property
		/// </summary>
		public void SetSpecialName() 
		{
			flags |= specialName;
		}

		/// <summary>
		/// Set the RTSpecialName attribute for this Event or Property
		/// </summary>
		public void SetRTSpecialName() 
		{
			flags |= rtSpecialName;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for an event
	/// </summary>
	public class Event : Feature {

		Type eventType;

		internal Event(string name, Type eType, ClassDef parent) 
			: base(name, parent) 
		{
			eventType = eType;
			tabIx = MDTable.Event;
		}

		/// <summary>
		/// Add the addon method to this event
		/// </summary>
		/// <param name="addon">the addon method</param>
		public void AddAddon(MethodDef addon) 
		{
			AddMethod(addon,MethodType.AddOn);
		}

		/// <summary>
		/// Add the removeon method to this event
		/// </summary>
		/// <param name="removeOn">the removeon method</param>
		public void AddRemoveOn(MethodDef removeOn) 
		{
			AddMethod(removeOn,MethodType.RemoveOn);
		}

		/// <summary>
		/// Add the fire method to this event
		/// </summary>
		/// <param name="fire">the fire method</param>
		public void AddFire(MethodDef fire) 
		{
			AddMethod(fire,MethodType.Fire);
		}

		/// <summary>
		/// Add another method to this event
		/// </summary>
		/// <param name="other">the method to be added</param>
		public void AddOther(MethodDef other) 
		{
			AddMethod(other,MethodType.Other);
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(name);
			for (int i=0; i < tide; i++) {
				md.AddToTable(MDTable.MethodSemantics,methods[i]);
			}
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.StringsIndexSize() + md.CodedIndexSize(CIx.TypeDefOrRef);
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.StringsIndex(nameIx);
			output.WriteCodedIndex(CIx.TypeDefOrRef,eventType);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 10; 
				case (CIx.HasSemantics) : return 0; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for the Property of a class
	/// </summary>
	public class Property : Feature {

		private static readonly byte PropertyTag = 0x8;
		private bool instance;
		MethodDef getterMeth;
		ConstantElem constVal;
		uint typeBlobIx = 0;
		Type[] parList;
		Type returnType;
		uint numPars = 0;

		internal Property(string name, Type retType, Type[] pars, ClassDef parent) : base(name, parent) 
		{
			returnType = retType;
			parList = pars;
			if (pars != null) numPars = (uint)pars.Length;
			tabIx = MDTable.Property;
		}

		/// <summary>
		/// Add a set method to this property
		/// </summary>
		/// <param name="setter">the set method</param>
		public void AddSetter(MethodDef setter) 
		{
			AddMethod(setter,MethodType.Setter);
		}

		/// <summary>
		/// Add a get method to this property
		/// </summary>
		/// <param name="getter">the get method</param>
		public void AddGetter(MethodDef getter) 
		{
			AddMethod(getter,MethodType.Getter);
			getterMeth = getter;
		}

		/// <summary>
		/// Add another method to this property
		/// </summary>
		/// <param name="other">the method</param>
		public void AddOther(MethodDef other) 
		{
			AddMethod(other,MethodType.Other);
		}

		/// <summary>
		/// Add an initial value for this property
		/// </summary>
		/// <param name="constVal">the initial value for this property</param>
		public void AddInitValue(Constant constVal) 
		{
			this.constVal = new ConstantElem(this,constVal);
		}

		public void SetInstance (bool isInstance)
		{
			this.instance = isInstance;
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(name);
			MemoryStream sig = new MemoryStream();
			byte tag = PropertyTag;
			if (instance)
				tag |= 0x20;
			sig.WriteByte(tag);
			MetaData.CompressNum(numPars,sig);
			returnType.TypeSig(sig);
			for (int i=0; i < numPars; i++) {
				parList[i].TypeSig(sig);
			}
			typeBlobIx = md.AddToBlobHeap(sig.ToArray());
			for (int i=0; i < tide; i++) {
				md.AddToTable(MDTable.MethodSemantics,methods[i]);
			}
			if (constVal != null) {
				md.AddToTable(MDTable.Constant,constVal);
				constVal.BuildTables(md);
			}
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.StringsIndexSize() + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.StringsIndex(nameIx);
			output.BlobIndex(typeBlobIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 9; 
				case (CIx.HasConst) : return 2; 
				case (CIx.HasSemantics) : return 1; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Base class for field/methods (member of a class)
	/// </summary>
	public abstract class Member : MetaDataElement {

		protected string name;
		protected uint nameIx = 0, sigIx = 0;

		internal Member(string memName)
		{
			name = memName;
			tabIx = MDTable.MemberRef;
		}

	}

	/*****************************************************************************/  
	/// <summary>
	/// Descriptor for a field of a class
	/// </summary>

	public abstract class Field : Member {

		protected static readonly byte FieldSig = 0x6;

		protected Type type;

		internal Field(string pfName, Type pfType) : base(pfName)
		{
			type = pfType;
		}

	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a field defined in a class of THIS assembly/module
	/// </summary>
	public class FieldDef : Field {

		//private static readonly uint PInvokeImpl = 0x2000;
		private static readonly ushort HasFieldRVA = 0x100;
		private static readonly ushort HasDefault = 0x8000;

		FieldRVA rva;
		ConstantElem constVal;
		FieldLayout layout;
		FieldMarshal marshalInfo;
		ushort flags;

		internal FieldDef(string name, Type fType) : base(name,fType) 
		{
			tabIx = MDTable.Field;
		}

		internal FieldDef(FieldAttr attrSet, string name, Type fType) : base(name, fType) 
		{
			flags = (ushort)attrSet;
			tabIx = MDTable.Field;
		}

		/// <summary>
		/// Add an attribute(s) to this field
		/// </summary>
		/// <param name="fa">the attribute(s) to be added</param>
		public void AddFieldAttr(FieldAttr fa) 
		{
			flags |= (ushort)fa;
		}

		/// <summary>
		/// Add a value for this field
		/// </summary>
		/// <param name="val">the value for the field</param>
		public void AddValue(Constant val) 
		{
			constVal = new ConstantElem(this,val);
			flags |= HasDefault;
		}

		/// <summary>
		/// Add an initial value for this field (at dataLabel) (.data)
		/// </summary>
		/// <param name="val">the value for the field</param>
		/// <param name="repeatVal">the number of repetitions of this value</param>
		public void AddDataValue(DataConstant val) 
		{
			flags |= HasFieldRVA;
			rva = new FieldRVA(this,val);
		}

		/// <summary>
		/// Set the offset of the field.  Used for sequential or explicit classes.
		/// (.field [offs])
		/// </summary>
		/// <param name="offs">field offset</param>
		public void SetOffset(uint offs) 
		{
			layout = new FieldLayout(this,offs);
		}

		/// <summary>
		/// Set the marshalling info for a field
		/// </summary>
		/// <param name="mInf"></param>
		public void SetMarshalInfo(NativeType marshallType) 
		{
			flags |= (ushort) FieldAttr.HasFieldMarshal;
			marshalInfo = new FieldMarshal(this,marshallType);
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(name);
			MemoryStream sig = new MemoryStream();
			sig.WriteByte(FieldSig);
			type.TypeSig(sig);
			sigIx = md.AddToBlobHeap(sig.ToArray());
			if (rva != null) {
				md.AddToTable(MDTable.FieldRVA,rva);
				rva.BuildTables(md);
			} else if (constVal != null) {
				md.AddToTable(MDTable.Constant,constVal);
				constVal.BuildTables(md);
			}
			if (layout != null) md.AddToTable(MDTable.FieldLayout,layout);
			if (marshalInfo != null) {
				md.AddToTable(MDTable.FieldMarshal,marshalInfo);
				marshalInfo.BuildTables(md);
			}
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 2 + md.StringsIndexSize() + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(flags);
			output.StringsIndex(nameIx);
			output.BlobIndex(sigIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasConst) : return 0; 
				case (CIx.HasCustomAttr) : return 1; 
				case (CIx.HasFieldMarshal) : return 0; 
				case (CIx.MemberForwarded) : return 0; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a field of a class defined in another assembly/module
	/// </summary>
	public class FieldRef : Field {

		MetaDataElement parent;

		internal FieldRef(MetaDataElement paren, string name, Type fType) : base(name, fType)   
		{
			parent = paren;
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(name);
			MemoryStream sig = new MemoryStream();
			sig.WriteByte(FieldSig);
			type.TypeSig(sig);
			sigIx = md.AddToBlobHeap(sig.ToArray());
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.CodedIndexSize(CIx.MemberRefParent) + md.StringsIndexSize() + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteCodedIndex(CIx.MemberRefParent,parent);
			output.StringsIndex(nameIx);
			output.BlobIndex(sigIx);
		}

		internal sealed override uint GetCodedIx(CIx code) { return 6; }

	}

	/**************************************************************************/  
	/// <summary>
	/// Base class for Method Descriptors
	/// </summary>

	public abstract class Method : Member {

		internal Method (string methName) : base (methName)
		{}

		public abstract void AddCallConv(CallConv cconv);
		internal abstract void TypeSig(MemoryStream sig);
		internal abstract uint GetSigIx(MetaData md);
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a method defined in THIS assembly/module
	/// IL     .method
	/// </summary>

	public class MethodDef : Method {

		private static readonly ushort PInvokeImpl = 0x2000;
		//private static readonly uint UnmanagedExport = 0x0008;
		// private static readonly byte LocalSigByte = 0x7;
		uint parIx = 0, textOffset = 0;
		private CallConv callConv = CallConv.Default;
		private int gen_param_count;

		MetaData metaData;
		CILInstructions code;
		Param[] parList;
		Local[] locals;
		bool initLocals;
		ushort methFlags = 0, implFlags = 0;
		int maxStack = 0, numPars = 0;
		bool entryPoint = false;
		LocalSig localSig;
		ArrayList varArgSigList;
		ImplMap pinvokeImpl;
		Param ret_param;

		internal MethodDef (MetaData md, string name, Param ret_param, Param [] pars)
			: this (md, 0, 0, name, ret_param, pars)
		{
		}

		internal MethodDef (MetaData md, MethAttr mAttrSet, ImplAttr iAttrSet, string name, 
				Param ret_param, Param [] pars) 
			: base (name)
		{
			methFlags = (ushort)mAttrSet;
			implFlags = (ushort)iAttrSet;
			this.ret_param = ret_param;
			metaData = md;
			parList = pars;
			if (parList != null) 
				numPars = parList.Length;
			tabIx = MDTable.Method;
		}

		internal Param[] GetPars() 
		{
			return parList;
		}

		internal override uint GetSigIx(MetaData md)
		{
			MemoryStream sig = new MemoryStream();
			TypeSig(sig);
			return md.AddToBlobHeap(sig.ToArray());
		}

		public override void AddCallConv(CallConv cconv)
		{
			callConv |= cconv;
		}
		
		/// <summary>
		/// Add some attributes to this method descriptor
		/// </summary>
		/// <param name="ma">the attributes to be added</param>
		public void AddMethAttribute(MethAttr ma) 
		{
			methFlags |= (ushort)ma;
		}

		/// <summary>
		/// Add some implementation attributes to this method descriptor
		/// </summary>
		/// <param name="ia">the attributes to be added</param>
		public void AddImplAttribute(ImplAttr ia) 
		{
			implFlags |= (ushort)ia;
		}

		public void AddPInvokeInfo(ModuleRef scope, string methName,
				PInvokeAttr callAttr) {
			pinvokeImpl = new ImplMap((ushort)callAttr,this,methName,scope);
			methFlags |= PInvokeImpl;
		}

		/// <summary>
		///  Add a named generic type parameter
		/// </summary>
		public GenericParameter AddGenericParameter (short index, string name) 
		{
			return AddGenericParameter (index, name, 0);
		}

		/// <summary>
		///  Add a named generic type parameter with attributes
		/// </summary>
		public GenericParameter AddGenericParameter (short index, string name, GenericParamAttributes attr) 
		{
			GenericParameter gp = new GenericParameter (this, metaData, index, name, attr);
			metaData.AddToTable (MDTable.GenericParam, gp);
			gen_param_count ++;
			return gp;
		}

		/// <summary>
		/// Set the maximum stack height for this method
		/// </summary>
		/// <param name="maxStack">the maximum height of the stack</param>
		public void SetMaxStack(int maxStack) 
		{
			this.maxStack = maxStack; 
		}

		/// <summary>
		/// Add local variables to this method
		/// </summary>
		/// <param name="locals">the locals to be added</param>
		/// <param name="initLocals">are locals initialised to default values</param>
		public void AddLocals(Local[] locals, bool initLocals) 
		{
			this.locals = locals;
			this.initLocals = initLocals;
		}

		/* Add Marshal info for return type */
		public void AddRetTypeMarshallInfo (NativeType marshallType) 
		{
			ret_param.AddMarshallInfo (marshallType);
		}

		/// <summary>
		/// Mark this method as having an entry point
		/// </summary>
		public void DeclareEntryPoint() 
		{
			entryPoint = true;
		}

		/// <summary>
		/// Create a code buffer for this method to add the IL instructions to
		/// </summary>
		/// <returns>a buffer for this method's IL instructions</returns>
		public CILInstructions CreateCodeBuffer() 
		{
			code = new CILInstructions(metaData);
			return code;
		}

		/// <summary>
		/// Make a method reference descriptor for this method to be used 
		/// as a callsite signature for this vararg method
		/// </summary>
		/// <param name="optPars">the optional pars for the vararg method call</param>
		/// <returns></returns>
		public MethodRef MakeVarArgSignature(Type[] optPars) 
		{
			Type[] pars = new Type[numPars];
			MethodRef varArgSig;
			for (int i=0; i < numPars; i++) {
				pars[i] = parList[i].GetParType();
			}
			varArgSig = new MethodRef (this, name, ret_param.GetParType (), pars, true, optPars, 0);

			if (varArgSigList == null)
				varArgSigList = new ArrayList ();
			varArgSigList.Add (varArgSig);
			return varArgSig;
		}

		internal sealed override void TypeSig(MemoryStream sig) 
		{
			sig.WriteByte((byte)callConv);
			if ((callConv & CallConv.Generic) == CallConv.Generic)
				MetaData.CompressNum ((uint) gen_param_count, sig);
			MetaData.CompressNum((uint)numPars,sig);

			ret_param.seqNo = 0;
			ret_param.TypeSig (sig);
			for (ushort i=0; i < numPars; i++) {
				parList[i].seqNo = (ushort)(i+1);
				parList[i].TypeSig(sig);
			}
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			if (pinvokeImpl != null) {
				md.AddToTable(MDTable.ImplMap,pinvokeImpl);
				pinvokeImpl.BuildTables(md);
			}
			if (entryPoint) md.SetEntryPoint(this);
			uint locToken = 0;
			if (locals != null) {
				localSig = new LocalSig(locals);
				md.AddToTable(MDTable.StandAloneSig,localSig);
				localSig.BuildTables(md);
				locToken = localSig.Token();
			}
			if (code != null) {
				code.CheckCode(locToken,initLocals,maxStack);
				textOffset = md.AddCode(code);
			}
			nameIx = md.AddToStringsHeap(name);
			sigIx = GetSigIx(md);
			parIx = md.TableIndex(MDTable.Param);
			if (ret_param.HasMarshalInfo || ret_param.HasCustomAttr) {
				md.AddToTable(MDTable.Param, ret_param);
				ret_param.BuildTables(md);
			}
			for (int i=0; i < numPars; i++) {
				md.AddToTable(MDTable.Param,parList[i]);
				parList[i].BuildTables(md);
			}
			if (varArgSigList != null) {
				foreach (MethodRef varArgSig in varArgSigList) {
					md.AddToTable(MDTable.MemberRef,varArgSig);
					varArgSig.BuildTables(md);
				}
			}
			// Console.WriteLine("method has " + numPars + " parameters");
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 8 + md.StringsIndexSize() + md.BlobIndexSize() + md.TableIndexSize(MDTable.Param);
		}

		internal sealed override void Write(FileImage output) 
		{
			if (ZeroRva ()) output.Write(0);
			else output.WriteCodeRVA(textOffset);
			output.Write(implFlags);
			output.Write(methFlags);
			output.StringsIndex(nameIx);
			output.BlobIndex(sigIx);
			output.WriteIndex(MDTable.Param,parIx);
		}

		internal bool ZeroRva () 
		{
			return (((methFlags & (ushort)MethAttr.Abstract) != 0) ||
					((implFlags & (ushort)ImplAttr.Runtime) != 0) ||
					((implFlags & (ushort)ImplAttr.InternalCall) != 0) || 
					(pinvokeImpl != null)); // TODO: Not entirely true but works for now
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 0; 
				case (CIx.HasDeclSecurity) : return 1; 
				case (CIx.MemberRefParent) : return 3; 
				case (CIx.MethodDefOrRef) : return 0; 
				case (CIx.MemberForwarded) : return 1; 
				case (CIx.CustomAttributeType) : return 2; 
				case (CIx.TypeOrMethodDef) : return 1; 
			}
			return 0;
		}

	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a method defined in another assembly/module
	/// </summary>
	public class MethodRef : Method {

		private static readonly byte Sentinel = 0x41;
		Type[] parList, optParList;
		MetaDataElement parent;
		uint numPars = 0, numOptPars = 0;
		CallConv callConv = CallConv.Default;
		Type retType;
		int gen_param_count;

		internal MethodRef(MetaDataElement paren, string name, Type retType,
				Type[] pars, bool varArgMeth, Type[] optPars, int gen_param_count) : base(name)
		{
			parent = paren;
			parList = pars;
			this.retType = retType;
			if (parList != null) numPars = (uint)parList.Length;
			if (varArgMeth) {
				optParList = optPars;
				if (optParList != null) numOptPars = (uint)optParList.Length;
				callConv = CallConv.Vararg;
			}
			this.gen_param_count = gen_param_count;
		}

		internal override uint GetSigIx(MetaData md)
		{
			MemoryStream sig = new MemoryStream();
			TypeSig(sig);
			return md.AddToBlobHeap(sig.ToArray());
		}

		public override void AddCallConv(CallConv cconv)
		{
			callConv |= cconv;
		}
		
		internal sealed override void TypeSig(MemoryStream sig) 
		{
			sig.WriteByte((byte)callConv);
			if ((callConv & CallConv.Generic) == CallConv.Generic)
				MetaData.CompressNum ((uint) gen_param_count, sig);
			MetaData.CompressNum(numPars+numOptPars,sig);
			retType.TypeSig(sig);
			for (int i=0; i < numPars; i++) {
				parList[i].TypeSig(sig);
			}
			if (numOptPars > 0) {
				sig.WriteByte(Sentinel);
				for (int i=0; i < numOptPars; i++) {
					optParList[i].TypeSig(sig);
				}
			}
		}

		internal sealed override void BuildTables(MetaData md) 
		{
			if (done) return;
			nameIx = md.AddToStringsHeap(name);
			sigIx = GetSigIx(md);
			done = true;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return md.CodedIndexSize(CIx.MemberRefParent) + md.StringsIndexSize() + md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.WriteCodedIndex(CIx.MemberRefParent,parent);
			output.StringsIndex(nameIx);
			output.BlobIndex(sigIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.HasCustomAttr) : return 6; 
				case (CIx.MethodDefOrRef) : return 1; 
				case (CIx.CustomAttributeType) : return 3; 
			}
			return 0;
		}

	}


	/**************************************************************************/  
	/// <summary>
	/// Descriptors for native types used for marshalling
	/// </summary>
	public class NativeType {
		public static readonly NativeType Void = new NativeType(0x01);
		public static readonly NativeType Boolean = new NativeType(0x02);
		public static readonly NativeType Int8 = new NativeType(0x03);
		public static readonly NativeType UInt8 = new NativeType(0x04);
		public static readonly NativeType Int16 = new NativeType(0x05);
		public static readonly NativeType UInt16 = new NativeType(0x06);
		public static readonly NativeType Int32 = new NativeType(0x07);
		public static readonly NativeType UInt32 = new NativeType(0x08);
		public static readonly NativeType Int64 = new NativeType(0x09);
		public static readonly NativeType UInt64 = new NativeType(0x0A);
		public static readonly NativeType Float32 = new NativeType(0x0B);
		public static readonly NativeType Float64 = new NativeType(0x0C);
		public static readonly NativeType Currency = new NativeType(0x0F);
		public static readonly NativeType BStr = new NativeType(0x13);
		public static readonly NativeType LPStr = new NativeType(0x14);
		public static readonly NativeType LPWStr = new NativeType(0x15);
		public static readonly NativeType LPTStr = new NativeType(0x16);
		public static readonly NativeType FixedSysString = new NativeType(0x17);
		public static readonly NativeType IUnknown = new NativeType(0x19);
		public static readonly NativeType IDispatch = new NativeType(0x1A);
		public static readonly NativeType Struct = new NativeType(0x1B);
		public static readonly NativeType Interface = new NativeType(0x1C);
		public static readonly NativeType Int = new NativeType(0x1F);
		public static readonly NativeType UInt = new NativeType(0x20);
		public static readonly NativeType ByValStr = new NativeType(0x22);
		public static readonly NativeType AnsiBStr = new NativeType(0x23);
		public static readonly NativeType TBstr = new NativeType(0x24);
		public static readonly NativeType VariantBool = new NativeType(0x25);
		public static readonly NativeType FuncPtr = new NativeType(0x26);
		public static readonly NativeType AsAny = new NativeType(0x28);
		public static readonly NativeType LPStruct = new NativeType(0x2b);
		public static readonly NativeType Error = new NativeType(0x2d);

		protected byte typeIndex;

		internal NativeType(byte tyIx) { typeIndex = tyIx; }
		internal byte GetTypeIndex() { return typeIndex; }

		internal virtual byte[] ToBlob() 
		{
			byte[] bytes = new byte[1];
			bytes[0] = GetTypeIndex();
			return bytes;
		}

	}

	public class FixedSysString : NativeType  {

		uint size;

		public FixedSysString (uint size) : base (NativeType.FixedSysString.GetTypeIndex ())
		{
			this.size = size;
		}

		internal override byte [] ToBlob () 
		{
			MemoryStream str = new MemoryStream ();
			str.WriteByte (GetTypeIndex ());
			MetaData.CompressNum (size, str);
			return str.ToArray ();
		}

	}  

	public class NativeArray : NativeType  {

		NativeType elemType;
		int numElem = -1, parNum = -1, elemMult = -1;

		public NativeArray(NativeType elemType) : this (elemType, -1, -1, -1) 
		{
			this.elemType = elemType;
		}

		/*    public NativeArray(NativeType elemType, int len) : base(0x2A) {
		      this.elemType = elemType;
		      this.len = len;
		      }
		 */

		public NativeArray(NativeType elemType, int numElem, int parNumForLen, int elemMult) : base(0x2A) 
		{
			this.elemType = elemType;
			this.numElem = numElem;
			parNum = parNumForLen;
			this.elemMult = elemMult;
		}

		public NativeArray(NativeType elemType, int numElem, int parNumForLen) 
			: this (elemType, numElem, parNumForLen, -1) 
		{
		}

		internal override byte[] ToBlob() 
		{
			MemoryStream str = new MemoryStream();
			str.WriteByte(GetTypeIndex());
			if (elemType == null) str.WriteByte(0x50);  // no info (MAX)
			else str.WriteByte(elemType.GetTypeIndex());

			/* see : mono/metadata/metadata.c:mono_metadata_parse_marshal_spec
			 * LAMESPEC: Older spec versions say elemMult comes before
			 * len. Newer spec versions don't talk about elemMult at
			 * all, but csc still emits it, and it is used to distinguish
			 * between parNum being 0, and parNum being omitted.
			 */

			if (parNum == -1)
				// <native_type> []
				return str.ToArray ();

			MetaData.CompressNum((uint) parNum,str);
			if (numElem != -1) {
				MetaData.CompressNum ((uint) numElem, str);
				if (elemMult != -1)
					// <native_type> [ int32 ]
					MetaData.CompressNum((uint) elemMult,str);
				//else <native_type> [ int32 + int32 ]
			} else if (elemMult != -1) {
				// When can this occur ?
				MetaData.CompressNum (0, str);
				MetaData.CompressNum((uint) elemMult,str);
			}
			//else <native_type> [ + int32 ]

			return str.ToArray();
		}

	}

	public class SafeArray : NativeType  {

		SafeArrayType elemType;
		bool hasElemType;

		public SafeArray() : base(0x1D) 
		{
		}

		public SafeArray(SafeArrayType elemType) : base(0x1D) 
		{
			this.elemType = elemType;
			hasElemType = true;
		}

		internal override byte[] ToBlob() 
		{
			byte[] bytes = new byte[hasElemType ? 2 : 1];
			bytes[0] = GetTypeIndex();
			if (hasElemType)
				bytes[1] = (byte)elemType;
			return bytes;
		}

	}

	public class FixedArray : NativeType  {

		uint numElem;

		//public FixedArray(NativeType elemType, int numElems) : base(0x1E) {
		public FixedArray(int numElems) : base(0x1E) 
		{
			//this.elemType = elemType;
			numElem = (uint)numElems;
		}

		internal override byte[] ToBlob() 
		{
			MemoryStream str = new MemoryStream();
			str.WriteByte(GetTypeIndex());
			MetaData.CompressNum(numElem,str);
			/* FIXME: 
			   fixed array [5] lpstr [2]
			   This format is not supported by ilasm 1.1.4322.2032, 
			   but is supported by 2.0.5125..
			   ilasm 1.1 only supports "fixed array [5]" 
			   if (elemType == null) str.WriteByte(0x50);  // no info (MAX)
			   else str.WriteByte(elemType.GetTypeIndex());*/

			return str.ToArray();
		}

	}

	public class CustomMarshaller : NativeType  {

		string typeName;
		string marshallerName;
		string cookie;

		public CustomMarshaller(string typeNameOrGUID, string marshallerName, 
				string optCookie) : base(0x2C) 
		{
			typeName = typeNameOrGUID;
			this.marshallerName = marshallerName;
			cookie = optCookie;
		}

		public CustomMarshaller(string marshallerName, string optCookie)
			:this (null, marshallerName, optCookie) 
		{
		}

		internal override byte[] ToBlob() 
		{
			MemoryStream str = new MemoryStream();
			BinaryWriter bw = new BinaryWriter(str,new UTF8Encoding());
			bw.Write(GetTypeIndex());
			//Native type name & unmanaged type - unused
			//See mono/metadata/metadata.c : mono_metadata_parse_marshal_spec
			bw.Write ((byte) 0); // Native Type name, unused 
			bw.Write ((byte) 0); // Unmanaged type, unused 
			if (marshallerName != null) {
				MetaData.CompressNum ((uint)marshallerName.Length, str);
				bw.Write(marshallerName.ToCharArray());
			} else { 
				bw.Write ((byte) 0);
			}
			if (cookie != null) {
				MetaData.CompressNum ((uint)cookie.Length, str);
				bw.Write(cookie.ToCharArray());
			} else {
				bw.Write ((byte) 0);
			}
			bw.Flush();
			return str.ToArray();
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for the Primitive types defined in IL
	/// </summary>
	public class PrimitiveType : Type {

		private string name;
		private int systemTypeIndex;
		public static int NumSystemTypes = 18;

		public static readonly PrimitiveType Void = new PrimitiveType(0x01,"Void",0);
		public static readonly PrimitiveType Boolean = new PrimitiveType(0x02,"Boolean",1);
		public static readonly PrimitiveType Char = new PrimitiveType(0x03,"Char",2);
		public static readonly PrimitiveType Int8 = new PrimitiveType(0x04,"SByte",3);
		public static readonly PrimitiveType UInt8 = new PrimitiveType(0x05,"Byte",4);
		public static readonly PrimitiveType Int16 = new PrimitiveType(0x06,"Int16",5);
		public static readonly PrimitiveType UInt16 = new PrimitiveType(0x07,"UInt16",6);
		public static readonly PrimitiveType Int32 = new PrimitiveType(0x08,"Int32",7);
		public static readonly PrimitiveType UInt32 = new PrimitiveType(0x09,"UInt32",8);
		public static readonly PrimitiveType Int64 = new PrimitiveType(0x0A,"Int64",9);
		public static readonly PrimitiveType UInt64 = new PrimitiveType(0x0B,"UInt64",10);
		public static readonly PrimitiveType Float32 = new PrimitiveType(0x0C,"Single",11);
		public static readonly PrimitiveType Float64 = new PrimitiveType(0x0D,"Double",12);
		public static readonly PrimitiveType String = new PrimitiveType(0x0E,"String",13);
		internal static readonly PrimitiveType Class = new PrimitiveType(0x12);
		internal static readonly PrimitiveType Var = new PrimitiveType(0x13);
		internal static readonly PrimitiveType GenericInst = new PrimitiveType(0x15);
		public static readonly PrimitiveType TypedRef = new PrimitiveType(0x16,"TypedReference",14);
		public static readonly PrimitiveType IntPtr = new PrimitiveType(0x18,"IntPtr",15);
		public static readonly PrimitiveType UIntPtr = new PrimitiveType(0x19,"UIntPtr",16);
		public static readonly PrimitiveType Object = new PrimitiveType(0x1C,"Object",17);
		internal static readonly PrimitiveType ClassType = new PrimitiveType(0x50);
		internal static readonly PrimitiveType SZArray = new PrimitiveType(0x1D);
		internal static readonly PrimitiveType MVar = new PrimitiveType(0x1E);
		internal static readonly PrimitiveType ValueType = new PrimitiveType(0x11, "ValueType", 18);
		public static readonly PrimitiveType NativeInt = IntPtr;
		public static readonly PrimitiveType NativeUInt = UIntPtr;

		internal PrimitiveType(byte typeIx) : base(typeIx) { }

		internal PrimitiveType(byte typeIx, string name, int STIx) : base(typeIx) 
		{
			this.name = name;
			this.systemTypeIndex = STIx;
		}

		internal string GetName() { return name; }

		internal int GetSystemTypeIx() { return systemTypeIndex; }

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);
		}

		internal override MetaDataElement GetTypeSpec(MetaData md) 
		{
			TypeSpec tS = md.GetPrimitiveTypeSpec(systemTypeIndex);
			if (tS == null) {
				tS = new TypeSpec(this,md);
				md.SetPrimitiveTypeSpec(systemTypeIndex,tS);
				md.AddToTable(MDTable.TypeSpec,tS);
			}
			return tS;
		}

	}

	public class PrimitiveTypeRef : Type
	{
		PrimitiveType type;
		MetaData metaData;

		internal PrimitiveTypeRef(PrimitiveType type, MetaData md)
			: base (0)
		{
			this.type = type;
			this.metaData = md;
		}

		internal uint TypeDefOrRefToken()
		{
			uint cIx = type.GetTypeSpec (metaData).Row;
			cIx = (cIx << 2) | 0x2;
			return cIx;
		}
	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for an pointer (type * or type &)
	/// </summary>
	public abstract class PtrType : Type {

		Type baseType;

		internal PtrType(Type bType, byte typeIx) : base(typeIx)
		{
			baseType = bType;
			tabIx = MDTable.TypeSpec;
		}

		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(typeIndex);
			baseType.TypeSig(str);
		}

	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a managed pointer (type &  or byref)
	/// </summary>

	public class ManagedPointer : PtrType {

		/// <summary>
		/// Create new managed pointer to baseType
		/// </summary>
		/// <param name="bType">the base type of the pointer</param>
		public ManagedPointer(Type baseType) : base(baseType,0x10) { }

	}
	/**************************************************************************/  
	/// <summary>
	/// Descriptor for an unmanaged pointer (type *)
	/// </summary>
	public class UnmanagedPointer : PtrType {

		/// <summary>
		/// Create a new unmanaged pointer to baseType
		/// </summary>
		/// <param name="baseType">the base type of the pointer</param>
		public UnmanagedPointer(Type baseType) : base(baseType, 0x0F) { }

	}

	/**************************************************************************/  

	public interface IExternRef  {
		ClassRef AddClass(string nsName, string name);
		ClassRef AddValueClass(string nsName, string name);
	}

	/// <summary>
	/// A reference to an external assembly (.assembly extern)
	/// </summary>
	public class AssemblyRef : ResolutionScope, IExternRef {

		private ushort major, minor, build, revision;
		uint flags, keyIx, hashIx, cultIx;
		bool hasVersion = false, isKeyToken = false;
		byte[] keyBytes;
		string culture;

		internal AssemblyRef(MetaData md, string name) : base(name,md) 
		{
			tabIx = MDTable.AssemblyRef;
		}

		public void AddAssemblyAttr (AssemAttr aa)
		{
			flags |= (uint)aa;
		}

		/// <summary>
		/// Add version information about this external assembly
		/// </summary>
		/// <param name="majVer">Major Version</param>
		/// <param name="minVer">Minor Version</param>
		/// <param name="bldNo">Build Number</param>
		/// <param name="revNo">Revision Number</param>
		public void AddVersionInfo(int majVer, int minVer, int bldNo, int revNo) 
		{
			major = (ushort)majVer;
			minor = (ushort)minVer;
			build = (ushort)bldNo;
			revision = (ushort)revNo;
			hasVersion = true;
		}

		/// <summary>
		/// Add the hash value for this external assembly
		/// </summary>
		/// <param name="hash">bytes of the hash value</param>
		public void AddHash(byte[] hash) 
		{
			hashIx = metaData.AddToBlobHeap(hash); 
		}

		/// <summary>
		/// Set the culture for this external assembly
		/// </summary>
		/// <param name="cult">the culture string</param>
		public void AddCulture(string cult) 
		{
			cultIx = metaData.AddToStringsHeap(cult);
			culture = cult;
		}

		/// <summary>
		/// Add the full public key for this external assembly
		/// </summary>
		/// <param name="key">bytes of the public key</param>
		public void AddKey(byte[] key) 
		{
			flags |= 0x0001;   // full public key
			keyBytes = key;
			keyIx = metaData.AddToBlobHeap(key); 
		}

		/// <summary>
		/// Add the public key token (low 8 bytes of the public key)
		/// </summary>
		/// <param name="key">low 8 bytes of public key</param>
		public void AddKeyToken(byte[] key) 
		{
			keyIx = metaData.AddToBlobHeap(key); 
			keyBytes = key;
			isKeyToken = true;
		}

		/// <summary>
		/// Add a class to this external assembly
		/// </summary>
		/// <param name="nsName">name space name</param>
		/// <param name="name">class name</param>
		/// <returns></returns>
		public virtual ClassRef AddClass(string nsName, string name) 
		{
			ClassRef aClass = new ClassRef(nsName,name,metaData);
			metaData.AddToTable(MDTable.TypeRef,aClass);
			aClass.SetParent(this);
			return aClass;
		}

		/// <summary>
		/// Add a value class to this external assembly
		/// </summary>
		/// <param name="nsName">name space name</param>
		/// <param name="name">class name</param>
		/// <returns></returns>
		public virtual ClassRef AddValueClass(string nsName, string name) 
		{
			ClassRef aClass = new ClassRef(nsName,name,metaData);
			metaData.AddToTable(MDTable.TypeRef,aClass);
			aClass.SetParent(this);
			aClass.MakeValueClass(ValueClass.ValueType);
			return aClass;
		}

		internal string TypeName() 
		{
			string result = name;
			if (hasVersion) 
				result = result + ", Version=" + major + "." + minor + "." + 
					build + "." + revision;
			if (keyBytes != null) {
				string tokenStr = "=";
				if (isKeyToken) tokenStr = "Token=";
				result = result + ", PublicKey" + tokenStr;
				for (int i=0; i < keyBytes.Length; i++) {
					result = result + Hex.Byte(keyBytes[i]);
				}
			}
			if (culture != null) 
				result = result + ", Culture=" + culture;
			return result;
		}

		internal sealed override uint Size(MetaData md) 
		{
			return 12 + 2 * md.StringsIndexSize() + 2 * md.BlobIndexSize();
		}

		internal sealed override void Write(FileImage output) 
		{
			output.Write(major);
			output.Write(minor);
			output.Write(build);
			output.Write(revision);
			output.Write(flags);
			output.BlobIndex(keyIx);
			output.StringsIndex(nameIx);
			output.StringsIndex(cultIx);
			output.BlobIndex(hashIx);
		}

		internal sealed override uint GetCodedIx(CIx code) 
		{
			switch (code) {
				case (CIx.ResolutionScope) : return 2; 
				case (CIx.HasCustomAttr) : return 15; 
				case (CIx.Implementation) : return 1; 
			}
			return 0;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Descriptor for a class defined in System (mscorlib)
	/// </summary>
	internal class SystemClass : ClassRef {

		PrimitiveType elemType; 

		internal SystemClass(PrimitiveType eType, AssemblyRef paren, MetaData md)
			: base("System",eType.GetName(),md) {
				elemType = eType;
				parent = paren;
			}

		internal override sealed MetaDataElement GetTypeSpec(MetaData md) 
		{
			if (typeSpec == null) typeSpec = (TypeSpec)elemType.GetTypeSpec(md);
			return typeSpec;
		}


		internal sealed override void TypeSig(MemoryStream str) 
		{
			str.WriteByte(elemType.GetTypeIndex());
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// The assembly for mscorlib.  
	/// </summary>
	public sealed class MSCorLib : AssemblyRef {

		private static readonly int valueTypeIx = 18;
		private readonly string systemName = "System";
		private Class[] systemClasses = new Class[valueTypeIx+2];
		private PrimitiveType[] systemTypes = new PrimitiveType[valueTypeIx];

		private static int[] specialNames = {
			PrimitiveType.Void.GetName().GetHashCode(),
			PrimitiveType.Boolean.GetName().GetHashCode(),
			PrimitiveType.Char.GetName().GetHashCode(),
			PrimitiveType.Int8.GetName().GetHashCode(),
			PrimitiveType.UInt8.GetName().GetHashCode(),
			PrimitiveType.Int16.GetName().GetHashCode(),
			PrimitiveType.UInt16.GetName().GetHashCode(),
			PrimitiveType.Int32.GetName().GetHashCode(),
			PrimitiveType.UInt32.GetName().GetHashCode(),
			PrimitiveType.Int64.GetName().GetHashCode(),
			PrimitiveType.UInt64.GetName().GetHashCode(),
			PrimitiveType.Float32.GetName().GetHashCode(),
			PrimitiveType.Float64.GetName().GetHashCode(),
			PrimitiveType.String.GetName().GetHashCode(),
			PrimitiveType.TypedRef.GetName().GetHashCode(),
			PrimitiveType.IntPtr.GetName().GetHashCode(),
			PrimitiveType.UIntPtr.GetName().GetHashCode(),
			PrimitiveType.Object.GetName().GetHashCode(),
			PrimitiveType.ValueType.GetName ().GetHashCode(),
			"Enum".GetHashCode()
		};

		internal MSCorLib(MetaData md) : base(md,"mscorlib") 
		{
			if (!PEFile.IsMSCorlib)
				md.AddToTable(MDTable.AssemblyRef,this);
			systemTypes[PrimitiveType.Void.GetSystemTypeIx()] = PrimitiveType.Void;
			systemTypes[PrimitiveType.Boolean.GetSystemTypeIx()] = PrimitiveType.Boolean;
			systemTypes[PrimitiveType.Char.GetSystemTypeIx()] = PrimitiveType.Char;
			systemTypes[PrimitiveType.Int8.GetSystemTypeIx()] = PrimitiveType.Int8;
			systemTypes[PrimitiveType.UInt8.GetSystemTypeIx()] = PrimitiveType.UInt8;
			systemTypes[PrimitiveType.Int16.GetSystemTypeIx()] = PrimitiveType.Int16;
			systemTypes[PrimitiveType.UInt16.GetSystemTypeIx()] = PrimitiveType.UInt16;
			systemTypes[PrimitiveType.Int32.GetSystemTypeIx()] = PrimitiveType.Int32;
			systemTypes[PrimitiveType.UInt32.GetSystemTypeIx()] = PrimitiveType.UInt32;
			systemTypes[PrimitiveType.Int64.GetSystemTypeIx()] = PrimitiveType.Int64;
			systemTypes[PrimitiveType.UInt64.GetSystemTypeIx()] = PrimitiveType.UInt64;
			systemTypes[PrimitiveType.Float32.GetSystemTypeIx()] = PrimitiveType.Float32;
			systemTypes[PrimitiveType.Float64.GetSystemTypeIx()] = PrimitiveType.Float64;
			systemTypes[PrimitiveType.IntPtr.GetSystemTypeIx()] = PrimitiveType.IntPtr;
			systemTypes[PrimitiveType.UIntPtr.GetSystemTypeIx()] = PrimitiveType.UIntPtr;
			systemTypes[PrimitiveType.String.GetSystemTypeIx()] = PrimitiveType.String;
			systemTypes[PrimitiveType.Object.GetSystemTypeIx()] = PrimitiveType.Object;
			systemTypes[PrimitiveType.TypedRef.GetSystemTypeIx()] = PrimitiveType.TypedRef;
		}

		/// <summary>
		/// Add a class to the mscorlib assembly
		/// </summary>
		/// <param name="nsName">name space name</param>
		/// <param name="name">class name</param>
		/// <returns></returns>
		public override ClassRef AddClass(string nsName, string name) 
		{
			/* This gets called by !mscorlib, for adding references INTO mscorlib, so
			   it should be returning ClassRef ..*/
			Class aClass = GetSpecialClass(nsName,name);
			if (aClass == null) {
				aClass = new ClassRef(nsName,name,metaData);
				metaData.AddToTable(MDTable.TypeRef,aClass);
				if (aClass is ClassRef)
					((ClassRef) aClass).SetParent(this);
			}
			//FIXME: Check for !ClassRef here?
			return (ClassRef) aClass;
		}

		private Class GetSpecialClass(string nsName,string name) 
		{
			if (nsName.CompareTo(systemName) != 0) return null;
			int hash = name.GetHashCode();
			for (int i=0; i < specialNames.Length; i++) {
				if (hash != specialNames[i])
					continue;
				if (systemClasses[i] == null) {
					if (i < valueTypeIx) {
						systemClasses[i] = new SystemClass(systemTypes[i],this,metaData);
						if ((systemTypes[i] != PrimitiveType.Object) &&
								(systemTypes[i] != PrimitiveType.String)) {
							systemClasses[i].MakeValueClass(ValueClass.ValueType);
						}
					} else {
						systemClasses[i] = new ClassRef(nsName,name,metaData);
						((ClassRef) systemClasses[i]).SetParent(this);
						if (!ClassDef.IsValueType (nsName, name) && !ClassDef.IsEnum (nsName, name))
							systemClasses[i].MakeValueClass(ValueClass.ValueType);
					}
					metaData.AddToTable(MDTable.TypeRef,systemClasses[i]);
				}
				return systemClasses[i];
			}
			return null;
		}

		internal void SetSpecialSystemClass (string nsName, string name, Class aClass) 
		{
			if (nsName != systemName) return;
			int hash = name.GetHashCode ();
			for (int i = 0; i < specialNames.Length; i++) {
				if (hash != specialNames [i])
					continue;
				if (systemClasses [i] == null) {
					systemClasses [i] = aClass;
				}
			}
		}

		internal Class GetSpecialSystemClass(PrimitiveType pType) 
		{
			int ix = pType.GetSystemTypeIx();
			if (systemClasses[ix] == null && !PEFile.IsMSCorlib) {
				systemClasses[ix] = new SystemClass(pType,this,metaData);
				metaData.AddToTable(MDTable.TypeRef,systemClasses[ix]);
			}
			return systemClasses[ix];
		}

		private ClassRef GetValueClass(string name, int hash) 
		{
			/* Called by MSCorLib.AddValueClass, which is called by
			   !mscorlib, for adding ref to value class INTO mscorlib,
			   so this should be classref */
			int ix = valueTypeIx;
			if (hash != specialNames[valueTypeIx]) ix++;
			if (systemClasses[ix] == null) {
				systemClasses[ix] = new ClassRef(systemName,name,metaData);
				((ClassRef) systemClasses[ix]).SetParent(this);
				((ClassRef) systemClasses[ix]).MakeValueClass(ValueClass.ValueType);
				metaData.AddToTable(MDTable.TypeRef,systemClasses[ix]);
			}
			return (ClassRef) systemClasses[ix];
		}

		internal Class ValueType() 
		{
			if (systemClasses[valueTypeIx] == null && !PEFile.IsMSCorlib) {
				ClassRef valType = new ClassRef("System","ValueType",metaData);
				valType.SetParent(this);
				valType.MakeValueClass(ValueClass.ValueType);
				metaData.AddToTable(MDTable.TypeRef,valType);
				systemClasses[valueTypeIx] = valType;
			}
			return systemClasses[valueTypeIx];
		}

		internal Class EnumType() 
		{
			/* Called by both mscorlib & !mscorlib, so can be
			   either ClassRef or ClassDef */
			//systemClasses [ valueTypeIx + 1] -> System.Enum
			if (systemClasses[valueTypeIx + 1] == null && !PEFile.IsMSCorlib) {
				ClassRef valType = new ClassRef("System","Enum",metaData);
				valType.SetParent(this);
				valType.MakeValueClass(ValueClass.Enum);
				metaData.AddToTable(MDTable.TypeRef,valType);
				systemClasses[valueTypeIx + 1] = valType;
			}
			return systemClasses[valueTypeIx + 1];
		}

		/// <summary>
		/// Add a value class to this external assembly
		/// </summary>
		/// <param name="nsName">name space name</param>
		/// <param name="name">class name</param>
		/// <returns></returns>
		public override ClassRef AddValueClass(string nsName, string name) 
		{
			if (nsName.CompareTo(systemName) == 0) {
				int hash = name.GetHashCode();
				if ((hash == specialNames[valueTypeIx]) ||
						(hash == specialNames[valueTypeIx+1])) {
					return GetValueClass(name,hash);
				}
			}
			ClassRef aClass = new ClassRef(nsName,name,metaData);
			metaData.AddToTable(MDTable.TypeRef,aClass);
			aClass.SetParent(this);
			aClass.MakeValueClass(ValueClass.ValueType);
			return aClass;
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// MetaData 
	///   Root (20 bytes + UTF-8 Version String + quad align padding)
	///   StreamHeaders (8 bytes + null terminated name string + quad align padding)
	///   Streams 
	///     #~        (always present - holds metadata tables)
	///     #Strings  (always present - holds identifier strings)
	///     #US       (Userstring heap)
	///     #Blob     (signature blobs)
	///     #GUID     (guids for assemblies or Modules)
	/// </summary>
	public class MetaData  {

		internal static readonly int[] CIxShiftMap = {2,2,5,1,2,3,1,1,1,2,3,2,1};
		private static readonly byte StringsHeapMask = 0x1;
		private static readonly byte GUIDHeapMask = 0x2;
		private static readonly byte BlobHeapMask = 0x4;
		private static readonly uint MetaDataSignature = 0x424A5342;
		private static readonly uint maxSmlIxSize = 0xFFFF;
		private static readonly uint max1BitSmlIx = 0x7FFF;
		private static readonly uint max2BitSmlIx = 0x3FFF;
		private static readonly uint max3BitSmlIx = 0x1FFF;
		private static readonly uint max5BitSmlIx = 0x7FF;
		// NOTE: version and stream name strings MUST always be quad padded
		private static readonly string version = "v4.0.30319\0\0";
		private static readonly char[] tildeName = {'#','~','\0','\0'};
		private static readonly char[] stringsName = {'#','S','t','r','i','n','g','s','\0','\0','\0','\0'};
		private static readonly char[] usName = {'#','U','S','\0'};
		private static readonly char[] guidName = {'#','G','U','I','D','\0','\0','\0'};
		private static readonly char[] blobName = {'#','B','l','o','b','\0','\0','\0'};
		private static readonly uint MetaDataHeaderSize = 20 + (uint)version.Length;
		private static readonly uint TildeHeaderSize = 24;
		private static readonly uint StreamHeaderSize = 8;
		private static readonly uint numMetaDataTables = (int)MDTable.GenericParamConstraint + 1;

		MetaDataStream strings, us, guid, blob;

		MetaDataStream[] streams = new MetaDataStream[5];
		uint numStreams = 5;
		uint tildeTide = 0, tildePadding = 0, tildeStart = 0;
		uint numTables = 0, resourcesSize = 0;
		ArrayList[] metaDataTables = new ArrayList[numMetaDataTables];
		ArrayList byteCodes = new ArrayList();
		uint codeSize = 0, codeStart, byteCodePadding = 0, metaDataSize = 0;
		ulong valid = 0, /*sorted = 0x000002003301FA00;*/ sorted = 0;
		bool[] largeIx = new bool[numMetaDataTables];
		bool[] lgeCIx = new bool[(int)CIx.MaxCIx];
		bool largeStrings = false, largeUS = false, largeGUID = false, largeBlob = false;
		private FileImage file;
		private byte heapSizes = 0;
		MetaDataElement entryPoint;
		BinaryWriter output;
		MSCorLib _mscorlib;
		private TypeSpec[] systemTypeSpecs = new TypeSpec[PrimitiveType.NumSystemTypes];
		long mdStart;
		private ArrayList cattr_list;
		private ArrayList declsec_list;
		ArrayList resources;            

		internal MetaData(FileImage file) 
		{
			// tilde = new MetaDataStream(tildeName,false,0);
			this.file = file;
			strings = new MetaDataStream(stringsName,new UTF8Encoding(),true);
			us = new MetaDataStream(usName,new UnicodeEncoding(),true);
			guid = new MetaDataStream(guidName,false);
			blob = new MetaDataStream(blobName,true);
			streams[1] = strings;
			streams[2] = us;
			streams[3] = guid;
			streams[4] = blob;
			for (int i=0; i < numMetaDataTables; i++) {
				largeIx[i] = false;
			}
			for (int i=0; i < lgeCIx.Length; i++) {
				lgeCIx[i] = false;
			}
		}

		public MSCorLib mscorlib {
			get {
				return _mscorlib ?? (_mscorlib = new MSCorLib (this));
			}
		}


		internal TypeSpec GetPrimitiveTypeSpec(int ix) 
		{
			return systemTypeSpecs[ix];
		}

		internal void SetPrimitiveTypeSpec(int ix, TypeSpec typeSpec) 
		{
			systemTypeSpecs[ix] = typeSpec;
		}

		internal uint Size() 
		{
			return metaDataSize;
		}

		private void CalcHeapSizes ()
		{
			if (strings.LargeIx()) {
				largeStrings = true;
				heapSizes |= StringsHeapMask;
			}
			if (guid.LargeIx()) {
				largeGUID = true;
				heapSizes |= GUIDHeapMask;
			}
			if (blob.LargeIx()) {
				largeBlob = true;
				heapSizes |= BlobHeapMask;
			}

			largeUS = us.LargeIx();
		}

		internal void StreamSize(byte mask) 
		{
			heapSizes |= mask;
		}

		internal uint AddToUSHeap(string str) 
		{
			if (str == null) return 0;
			return us.Add(str,true);
		}

		internal uint AddToUSHeap(byte[] str) 
		{
			if (str == null) return 0;
			return us.Add (str, true);
		}

		internal uint AddToStringsHeap(string str) 
		{
			if ((str == null) || (str.CompareTo("") == 0)) return 0;
			return strings.Add(str,false);
		}

		internal uint AddToGUIDHeap(Guid guidNum) 
		{
			return guid.Add(guidNum, false);
		}

		internal uint AddToBlobHeap(byte[] blobBytes) 
		{
			if (blobBytes == null) return 0;
			return blob.Add(blobBytes, true);
		}

		internal uint AddToBlobHeap(byte val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(sbyte val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(ushort val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(short val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(uint val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(int val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(ulong val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(long val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(float val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(double val) 
		{
			return blob.Add(val, true);
		}

		internal uint AddToBlobHeap(string val) 
		{
			return blob.Add(val,true);
		}

		internal void AddCustomAttribute (CustomAttribute cattr)
		{
			if (cattr_list == null)
				cattr_list = new ArrayList ();
			cattr_list.Add (cattr);
		}

		internal void AddDeclSecurity (BaseDeclSecurity decl_sec)
		{
			if (declsec_list == null)
				declsec_list = new ArrayList ();
			declsec_list.Add (decl_sec);
		}

		private ArrayList GetTable(MDTable tableIx) 
		{
			int tabIx = (int)tableIx;
			if (metaDataTables[tabIx] == null) {
				metaDataTables[tabIx] = new ArrayList();
				valid |= ((ulong)0x1 << tabIx);
				// Console.WriteLine("after creating table " + tableIx + "(" + tabIx + ") valid = " + valid);
				numTables++;
			}
			return metaDataTables[tabIx];
		}

		internal void AddToTable(MDTable tableIx, MetaDataElement elem) 
		{
			if (elem.Row > 0) {
				// Console.Out.WriteLine("ERROR - element already in table " + tableIx);
				return;
			}
			// updates Row field of the element
			// Console.WriteLine("Adding element to table " + (uint)tableIx);
			ArrayList table = GetTable(tableIx);
			elem.Row = (uint)table.Count + 1;
			table.Add(elem);
		}

		internal uint TableIndex(MDTable tableIx) 
		{
			if (metaDataTables[(int)tableIx] == null) return 1;
			return (uint)metaDataTables[(int)tableIx].Count+1;
		}

		internal uint AddCode(CILInstructions byteCode) 
		{
			byteCodes.Add(byteCode);
			uint offset = codeSize + codeStart;
			codeSize += byteCode.GetCodeSize();
			return offset;
		}

		internal void SetEntryPoint(MetaDataElement ep) 
		{
			entryPoint = ep;
		}

		internal uint AddResource(byte[] resBytes) 
		{
			if (resources == null) resources = new ArrayList ();
			resources.Add (resBytes);
			uint offset = resourcesSize;
			resourcesSize += (uint)resBytes.Length + 4;
			return offset;
		}

		internal void AddData(DataConstant cVal) 
		{
			file.AddInitData(cVal);
		}

		internal static void CompressNum(uint val, MemoryStream sig) 
		{
			if (val <= 0x7F) {
				sig.WriteByte((byte)val);
			} else if (val <= 0x3FFF) {
				byte b1 = (byte)((val >> 8) | 0x80);
				byte b2 = (byte)(val & FileImage.iByteMask[0]);
				sig.WriteByte(b1);
				sig.WriteByte(b2);
			} else {
				byte b1 = (byte)((val >> 24) | 0xC0);
				byte b2 = (byte)((val & FileImage.iByteMask[2]) >> 16);
				byte b3 = (byte)((val & FileImage.iByteMask[1]) >> 8);;
				byte b4 = (byte)(val & FileImage.iByteMask[0]);
				sig.WriteByte(b1);
				sig.WriteByte(b2);
				sig.WriteByte(b3);
				sig.WriteByte(b4);
			}
		}

		internal uint CodeSize() 
		{
			return codeSize + byteCodePadding;
		}

		internal uint GetResourcesSize() 
		{ 
			return resourcesSize; 
		}

		internal uint StringsIndexSize() 
		{
			if (largeStrings) return 4;
			return 2;
		}

		internal uint GUIDIndexSize() 
		{
			if (largeGUID) return 4;
			return 2;
		}

		internal uint USIndexSize() 
		{
			if (largeUS) return 4;
			return 2;
		}

		internal uint BlobIndexSize() 
		{
			if (largeBlob) return 4;
			return 2;
		}

		internal uint CodedIndexSize(CIx code) 
		{
			if (lgeCIx[(uint)code]) return 4;
			return 2;
		}

		internal uint TableIndexSize(MDTable tabIx) 
		{
			if (largeIx[(uint)tabIx]) return 4;
			return 2;
		}

		private void SetIndexSizes() 
		{
			for (int i=0; i < numMetaDataTables; i++) {
				if (metaDataTables[i] == null)
					continue;

				uint count = (uint)metaDataTables[i].Count;
				if (count > maxSmlIxSize)
					largeIx[i] = true;

				MDTable tabIx = (MDTable)i;
				if (count > max5BitSmlIx) {
					if (tabIx == MDTable.Method || tabIx == MDTable.Field || tabIx == MDTable.TypeRef ||
						tabIx == MDTable.TypeDef || tabIx == MDTable.Param || tabIx == MDTable.InterfaceImpl ||
						tabIx == MDTable.MemberRef || tabIx == MDTable.Module || tabIx == MDTable.DeclSecurity ||
						tabIx == MDTable.Property || tabIx == MDTable.Event || tabIx == MDTable.StandAloneSig ||
						tabIx == MDTable.ModuleRef || tabIx == MDTable.TypeSpec || tabIx == MDTable.Assembly ||
						tabIx == MDTable.AssemblyRef || tabIx == MDTable.File || tabIx == MDTable.ExportedType ||
						tabIx == MDTable.ManifestResource || tabIx == MDTable.GenericParam)
					lgeCIx[(int)CIx.HasCustomAttr] = true;
				}
				if (count > max3BitSmlIx) {
					if (tabIx == MDTable.Method || tabIx == MDTable.MemberRef)
						lgeCIx[(int)CIx.CustomAttributeType] = true;
					if (tabIx == MDTable.TypeDef || tabIx == MDTable.TypeRef || tabIx == MDTable.ModuleRef ||
						tabIx == MDTable.Method || tabIx == MDTable.TypeSpec)
						lgeCIx[(int)CIx.MemberRefParent] = true;
				}
				if (count > max2BitSmlIx) {
					if ((tabIx == MDTable.Field) || (tabIx == MDTable.Param) || (tabIx == MDTable.Property)) 
						lgeCIx[(int)CIx.HasConst] = true;
					if ((tabIx == MDTable.TypeDef) || (tabIx == MDTable.TypeRef) || (tabIx == MDTable.TypeSpec))
						lgeCIx[(int)CIx.TypeDefOrRef] = true;
					if ((tabIx == MDTable.TypeDef) || (tabIx == MDTable.Method) || (tabIx == MDTable.Assembly))
						lgeCIx[(int)CIx.HasDeclSecurity] = true;
					if ((tabIx == MDTable.File) || (tabIx == MDTable.AssemblyRef) || (tabIx == MDTable.ExportedType))
						lgeCIx[(int)CIx.Implementation] = true;
					if ((tabIx == MDTable.Module) || (tabIx == MDTable.ModuleRef) || (tabIx == MDTable.AssemblyRef) || (tabIx == MDTable.TypeRef))
						lgeCIx[(int)CIx.ResolutionScope] = true;
				}
				if (count > max1BitSmlIx) {
					if ((tabIx == MDTable.Field) || (tabIx == MDTable.Param)) 
						lgeCIx[(int)CIx.HasFieldMarshal] = true;
					if ((tabIx == MDTable.Event) || (tabIx == MDTable.Property)) 
						lgeCIx[(int)CIx.HasSemantics] = true;
					if ((tabIx == MDTable.Method) || (tabIx == MDTable.MemberRef)) 
						lgeCIx[(int)CIx.MethodDefOrRef] = true;
					if ((tabIx == MDTable.Field) || (tabIx == MDTable.Method)) 
						lgeCIx[(int)CIx.MemberForwarded] = true; 
					if ((tabIx == MDTable.TypeDef) || (tabIx == MDTable.Method)) 
						lgeCIx[(int)CIx.TypeOrMethodDef] = true; 
				}
			}
		}

		private void SetStreamOffsets() 
		{
			uint sizeOfHeaders = StreamHeaderSize + (uint)tildeName.Length;
			for (int i=1; i < numStreams; i++) {
				sizeOfHeaders += streams[i].headerSize();
			}
			metaDataSize = MetaDataHeaderSize + sizeOfHeaders;
			tildeStart = metaDataSize;
			metaDataSize += tildeTide + tildePadding;
			for (int i=1; i < numStreams; i++) {
				streams[i].Start = metaDataSize;
				metaDataSize += streams[i].Size();
				streams[i].WriteDetails();
			}
		}

		internal void CalcTildeStreamSize() 
		{
			CalcHeapSizes ();
			//tilde.SetIndexSizes(strings.LargeIx(),us.LargeIx(),guid.LargeIx(),blob.LargeIx());
			tildeTide = TildeHeaderSize;
			tildeTide += 4 * numTables;
			//Console.WriteLine("Tilde header + sizes = " + tildeTide);
			for (int i=0; i < numMetaDataTables; i++) {
				if (metaDataTables[i] != null) {
					ArrayList table = metaDataTables[i];
					// Console.WriteLine("Meta data table " + i + " at offset " + tildeTide);
					tildeTide += (uint)table.Count * ((MetaDataElement)table[0]).Size(this);
					// Console.WriteLine("Metadata table " + i + " has size " + table.Count);
					// Console.WriteLine("tildeTide = " + tildeTide);
				}
			}
			if ((tildeTide % 4) != 0) tildePadding = 4 - (tildeTide % 4);
			//Console.WriteLine("tildePadding = " + tildePadding);
		}

		internal void WriteTildeStream(FileImage output) 
		{
			output.Seek(0,SeekOrigin.Current);
			output.Write((uint)0); // Reserved
			output.Write((byte)2); // MajorVersion
			output.Write((byte)0); // MinorVersion
			output.Write(heapSizes);
			output.Write((byte)1); // Reserved
			output.Write(valid);
			output.Write(sorted);
			
			for (int i=0; i < numMetaDataTables; i++) {
				if (metaDataTables[i] != null) {
					uint count = (uint)metaDataTables[i].Count;
					output.Write(count);
				}
			}
			
			output.Seek(0,SeekOrigin.Current);
			// Console.WriteLine("Starting metaData tables at " + tabStart);
			for (int i=0; i < numMetaDataTables; i++) {
				if (metaDataTables[i] != null) {
					// Console.WriteLine("Starting metaData table " + i + " at " + (output.Seek(0,SeekOrigin.Current) - startTilde));
					ArrayList table = metaDataTables[i];
					for (int j=0; j < table.Count; j++) {
						((MetaDataElement)table[j]).Write(output);
					}
				}
			}
			// Console.WriteLine("Writing padding at " + output.Seek(0,SeekOrigin.Current));
			for (int i=0; i < tildePadding; i++) output.Write((byte)0);
		}

		private void BuildTable(ArrayList table) 
		{
			if (table == null) return;
			for (int j=0; j < table.Count; j++) {
				((MetaDataElement)table[j]).BuildTables(this);
			}
		}

		private void SortTable (ArrayList mTable) 
		{
			if (mTable == null) return;
			mTable.Sort();
			for (int i=0; i < mTable.Count; i++) {
				((MetaDataElement)mTable[i]).Row = (uint)i+1;
			}
		}

		internal void BuildMetaData(uint codeStartOffset) 
		{
			codeStart = codeStartOffset;
			BuildTable(metaDataTables[(int)MDTable.TypeDef]);
			BuildTable(metaDataTables[(int)MDTable.TypeSpec]);
			BuildTable(metaDataTables[(int)MDTable.MemberRef]);
			BuildTable(metaDataTables[(int)MDTable.GenericParam]);
			BuildTable(metaDataTables[(int)MDTable.MethodSpec]);
			BuildTable(metaDataTables[(int)MDTable.GenericParamConstraint]);
			BuildTable(metaDataTables[(int)MDTable.ManifestResource]);

			if (cattr_list != null) {
				foreach (CustomAttribute cattr in cattr_list)
					cattr.BuildTables (this);
			}

			if (declsec_list != null) {
				foreach (BaseDeclSecurity decl_sec in declsec_list)
					decl_sec.BuildTables (this);
			}

			/*      for (int i=0; i < metaDataTables.Length; i++) {
				ArrayList table = metaDataTables[i];
				if (table != null) {
				for (int j=0; j < table.Count; j++) {
				((MetaDataElement)table[j]).BuildTables(this);
				}
				}
				}
			 */

			SetIndexSizes();
			for (int i=1; i < numStreams; i++) {
				streams[i].EndStream();
			}
			CalcTildeStreamSize();
			SetStreamOffsets();
			byteCodePadding = NumToAlign(codeSize,4);
			if (entryPoint != null) file.SetEntryPoint(entryPoint.Token());

			// Check ordering of specific tables
			// Constant, CustomAttribute, FieldMarshal, DeclSecurity, MethodSemantics
			// ImplMap, GenericParam
			// Need to load GenericParamConstraint AFTER GenericParam table in correct order
			// The tables:
			//   InterfaceImpl, ClassLayout, FieldLayout, MethodImpl, FieldRVA, NestedClass
			// will _ALWAYS_ be in the correct order as embedded in BuildMDTables

			SortTable(metaDataTables[(int)MDTable.Constant]);
			SortTable(metaDataTables[(int)MDTable.FieldMarshal]);
			SortTable(metaDataTables[(int)MDTable.DeclSecurity]);
			SortTable(metaDataTables[(int)MDTable.MethodSemantics]);
			SortTable(metaDataTables[(int)MDTable.MethodImpl]);
			SortTable(metaDataTables[(int)MDTable.ImplMap]);
			if (metaDataTables[(int)MDTable.GenericParam] != null) {
				SortTable(metaDataTables[(int)MDTable.GenericParam]);
				// Now add GenericParamConstraints
				/*for (int i=0; i < metaDataTables[(int)MDTable.GenericParam].Count; i++) {
				  ((GenericParameter)metaDataTables[(int)MDTable.GenericParam][i]).AddConstraints(this);
				  }*/
			}
			SortTable(metaDataTables[(int)MDTable.GenericParamConstraint]);
			SortTable(metaDataTables[(int)MDTable.CustomAttribute]);

		}

		internal void WriteByteCodes(FileImage output) 
		{
			for (int i=0; i < byteCodes.Count; i++) {
				((CILInstructions)byteCodes[i]).Write(output);
			}
			for (int i=0; i < byteCodePadding; i++) {
				output.Write((byte)0);
			}
		}

		internal void WriteResources (FileImage output) 
		{
			if (resources == null) return;
			for (int i = 0; i < resources.Count; i ++) {
				byte [] resBytes = (byte []) resources [i];
				output.Write ((uint) resBytes.Length);
				output.Write (resBytes);
			} 
		}

		internal void WriteMetaData(FileImage output) 
		{
			this.output = output;
			mdStart = output.Seek(0,SeekOrigin.Current);
			// Console.WriteLine("Writing metaData at " + Hex.Long(mdStart));
			output.Write(MetaDataSignature);
			output.Write((short)1);  // Major Version
			output.Write((short)1);  // Minor Version  ECMA = 0, PEFiles = 1
			output.Write(0);         // Reserved
			output.Write(version.Length);
			output.Write(version.ToCharArray());   // version string is already zero padded
			output.Write((short)0);
			output.Write((ushort)numStreams);
			// write tilde header
			output.Write(tildeStart);
			output.Write(tildeTide + tildePadding);
			output.Write(tildeName);
			for (int i=1; i < numStreams; i++) streams[i].WriteHeader(output);
			// Console.WriteLine("Writing tilde stream at " + output.Seek(0,SeekOrigin.Current) + " = " + tildeStart);
			WriteTildeStream(output);
			for (int i=1; i < numStreams; i++) streams[i].Write(output);
			// Console.WriteLine("Finished Writing metaData at " + output.Seek(0,SeekOrigin.Current));
		}

		internal bool LargeStringsIndex() { return strings.LargeIx(); }
		internal bool LargeGUIDIndex() { return guid.LargeIx(); }
		internal bool LargeUSIndex() { return us.LargeIx(); }
		internal bool LargeBlobIndex() { return blob.LargeIx(); }

		internal bool LargeIx(MDTable tabIx) { return largeIx[(uint)tabIx]; }


		private uint NumToAlign(uint val, uint alignVal) 
		{
			if ((val % alignVal) == 0) return 0;
			return alignVal - (val % alignVal);
		}

		internal void WriteCodedIndex(CIx code, MetaDataElement elem, FileImage output) 
		{
			uint ix = 0;
			if (elem != null) { 
				ix = (elem.Row << CIxShiftMap[(uint)code]) | elem.GetCodedIx(code);
				// Console.WriteLine("coded index = " + ix + " row = " + elem.Row);
				//} else {
				// Console.WriteLine("elem for coded index is null");
			}
			if (lgeCIx[(uint)code]) 
				output.Write(ix);
			else
				output.Write((ushort)ix);
		}

	}

	/**************************************************************************/  
	/// <summary>
	/// Stream in the Meta Data  (#Strings, #US, #Blob and #GUID)
	/// </summary>

	internal class MetaDataStream : BinaryWriter  {

		private static readonly uint StreamHeaderSize = 8;
		private static uint maxSmlIxSize = 0xFFFF;

		private uint start = 0; 
		uint size = 0, tide = 1;
		bool largeIx = false;
		uint sizeOfHeader;
		char[] name;
		Hashtable htable = new Hashtable();
		Hashtable btable = new Hashtable (new ByteArrayHashCodeProvider (), new ByteArrayComparer ());
		bool addInitByte = false;
		bool initByteAdded = false;

		internal MetaDataStream(char[] name, bool addInitByte) : base(new MemoryStream()) 
		{
			this.addInitByte = addInitByte;
			this.name = name;
			sizeOfHeader = StreamHeaderSize + (uint)name.Length;
		}

		internal MetaDataStream(char[] name, System.Text.Encoding enc, bool addInitByte) : base(new MemoryStream(),enc) 
		{
			this.addInitByte = addInitByte;
			this.name = name;
			sizeOfHeader = StreamHeaderSize + (uint)name.Length;
		}

		void AddInitByte () {
			if (addInitByte && !initByteAdded) {
				Write((byte)0);
				size += 1;
				initByteAdded = true;
			}
		}
		public uint Start {
			get { return start; }
			set { start = value; }
		}

		internal uint headerSize() 
		{
			// Console.WriteLine(name + " stream has headersize of " + sizeOfHeader);
			return sizeOfHeader;
		}

		internal void SetSize(uint siz) 
		{
			size = siz;
		}

		internal uint Size() 
		{
			return size;
		}

		internal bool LargeIx() 
		{
			return largeIx;
		}

		internal void WriteDetails() 
		{
			// Console.WriteLine(name + " - size = " + size);
		}

		internal uint Add(string str, bool prependSize) 
		{
			AddInitByte ();
			Object val = htable[str];
			uint index = 0;
			if (val == null) { 
				index = size;
				htable[str] = index;
				char[] arr = str.ToCharArray();
				if (prependSize) CompressNum((uint)arr.Length*2+1);
				Write(arr);
				Write((byte)0);
				size = (uint)Seek(0,SeekOrigin.Current);
			} else {
				index = (uint)val;
			}
			return index;
		}
		internal uint Add (byte[] str, bool prependSize) 
		{
			AddInitByte ();
			Object val = btable [str];
			uint index = 0;
			if (val == null) {
				index = size;
				btable [str] = index;
				if (prependSize) CompressNum ((uint) str.Length);
				Write (str);
				size = (uint) Seek (0, SeekOrigin.Current);
			} else {
				index = (uint) val;
			}
			return index;
		}


		internal uint Add(Guid guid, bool prependSize) 
		{
			AddInitByte ();
			byte [] b = guid.ToByteArray ();
			if (prependSize) CompressNum ((uint) b.Length);
			Write(guid.ToByteArray());
			size =(uint)Seek(0,SeekOrigin.Current);
			return tide++;
		}

		internal uint Add(byte[] blob) 
		{
			AddInitByte ();
			uint ix = size;
			CompressNum((uint)blob.Length);
			Write(blob);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(byte val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (1);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(sbyte val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (1);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(ushort val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (2);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(short val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (2);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(uint val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (4);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(int val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (4);
			Write (val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(ulong val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (8);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(long val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (8);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(float val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (4);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		internal uint Add(double val, bool prependSize) 
		{
			AddInitByte ();
			uint ix = size;
			if (prependSize) CompressNum (8);
			Write(val);
			size = (uint)Seek(0,SeekOrigin.Current);
			return ix;
		}

		private void CompressNum(uint val) 
		{
			if (val < 0x7F) {
				Write((byte)val);
			} else if (val < 0x3FFF) {
				byte b1 = (byte)((val >> 8) | 0x80);
				byte b2 = (byte)(val & FileImage.iByteMask[0]);
				Write(b1);
				Write(b2);
			} else {
				byte b1 = (byte)((val >> 24) | 0xC0);
				byte b2 = (byte)((val & FileImage.iByteMask[2]) >> 16);
				byte b3 = (byte)((val & FileImage.iByteMask[1]) >> 8);;
				byte b4 = (byte)(val & FileImage.iByteMask[0]);
				Write(b1);
				Write(b2);
				Write(b3);
				Write(b4);
			}
		}

		private void QuadAlign() 
		{
			if ((size % 4) != 0) {
				uint pad = 4 - (size % 4);
				size += pad;
				for (int i=0; i < pad; i++) {
					Write((byte)0);
				}
			}
		}

		internal void EndStream() 
		{
			QuadAlign();
			if (size > maxSmlIxSize) {
				largeIx = true;
			}
		}

		internal void WriteHeader(BinaryWriter output) 
		{
			output.Write(start);
			output.Write(size);
			output.Write(name);
		}

		internal virtual void Write(BinaryWriter output) 
		{
			// Console.WriteLine("Writing " + name + " stream at " + output.Seek(0,SeekOrigin.Current) + " = " + start);
			MemoryStream str = (MemoryStream)BaseStream;
			output.Write(str.ToArray());
		}

	}

	/**************************************************************************/  
	class ByteArrayComparer : IComparer {

		public int Compare (object x, object y)
		{
			byte [] a = (byte []) x;
			byte [] b = (byte []) y;
			int len = a.Length;

			if (b.Length != len)
				return 1;

			for (int i = 0; i < len; ++i)
				if (a [i] != b [i])
					return 1;
			return 0;
		}
	}

	class ByteArrayHashCodeProvider : IHashCodeProvider {

		public int GetHashCode (Object key)
		{
			byte [] arr = (byte []) key;
			int len = arr.Length;
			int h = 0;

			for (int i = 0; i < len; ++i)
				h = (h << 5) - h + arr [i];

			return h;
		}

	}


}