//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2015 Jb Evain
// Copyright (c) 2008 - 2011 Novell, Inc.
//
// Licensed under the MIT/X11 license.
//

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Text;

using Mono.Collections.Generic;
using Mono.Cecil.Cil;
using Mono.Cecil.Metadata;
using Mono.Cecil.PE;

using RVA = System.UInt32;

namespace Mono.Cecil {

	abstract class ModuleReader {

		readonly protected ModuleDefinition module;

		protected ModuleReader (Image image, ReadingMode mode)
		{
			this.module = new ModuleDefinition (image);
			this.module.ReadingMode = mode;
		}

		protected abstract void ReadModule ();
		public abstract void ReadSymbols (ModuleDefinition module);

		protected void ReadModuleManifest (MetadataReader reader)
		{
			reader.Populate (module);

			ReadAssembly (reader);
		}

		void ReadAssembly (MetadataReader reader)
		{
			var name = reader.ReadAssemblyNameDefinition ();
			if (name == null) {
				module.kind = ModuleKind.NetModule;
				return;
			}

			var assembly = new AssemblyDefinition ();
			assembly.Name = name;

			module.assembly = assembly;
			assembly.main_module = module;
		}

		public static ModuleDefinition CreateModule (Image image, ReaderParameters parameters)
		{
			var reader = CreateModuleReader (image, parameters.ReadingMode);
			var module = reader.module;

			if (parameters.assembly_resolver != null)
				module.assembly_resolver = Disposable.NotOwned (parameters.assembly_resolver);

			if (parameters.metadata_resolver != null)
				module.metadata_resolver = parameters.metadata_resolver;

			if (parameters.metadata_importer_provider != null)
				module.metadata_importer = parameters.metadata_importer_provider.GetMetadataImporter (module);

			if (parameters.reflection_importer_provider != null)
				module.reflection_importer = parameters.reflection_importer_provider.GetReflectionImporter (module);

			GetMetadataKind (module, parameters);

			reader.ReadModule ();

			ReadSymbols (module, parameters);

			reader.ReadSymbols (module);

			if (parameters.ReadingMode == ReadingMode.Immediate)
				module.MetadataSystem.Clear ();

			return module;
		}

		static void ReadSymbols (ModuleDefinition module, ReaderParameters parameters)
		{
			var symbol_reader_provider = parameters.SymbolReaderProvider;

			if (symbol_reader_provider == null && parameters.ReadSymbols)
				symbol_reader_provider = new DefaultSymbolReaderProvider ();

			if (symbol_reader_provider != null) {
				module.SymbolReaderProvider = symbol_reader_provider;

				var reader = parameters.SymbolStream != null
					? symbol_reader_provider.GetSymbolReader (module, parameters.SymbolStream)
					: symbol_reader_provider.GetSymbolReader (module, module.FileName);

				if (reader != null) {
					try {
						module.ReadSymbols (reader, parameters.ThrowIfSymbolsAreNotMatching);
					} catch (Exception) {
						reader.Dispose ();
						throw;
					}
				}
			}

			if (module.Image.HasDebugTables ())
				module.ReadSymbols (new PortablePdbReader (module.Image, module));
		}

		static void GetMetadataKind (ModuleDefinition module, ReaderParameters parameters)
		{
			if (!parameters.ApplyWindowsRuntimeProjections) {
				module.MetadataKind = MetadataKind.Ecma335;
				return;
			}

			var runtime_version = module.RuntimeVersion;

			if (!runtime_version.Contains ("WindowsRuntime"))
				module.MetadataKind = MetadataKind.Ecma335;
			else if (runtime_version.Contains ("CLR"))
				module.MetadataKind = MetadataKind.ManagedWindowsMetadata;
			else
				module.MetadataKind = MetadataKind.WindowsMetadata;
		}

		static ModuleReader CreateModuleReader (Image image, ReadingMode mode)
		{
			switch (mode) {
			case ReadingMode.Immediate:
				return new ImmediateModuleReader (image);
			case ReadingMode.Deferred:
				return new DeferredModuleReader (image);
			default:
				throw new ArgumentException ();
			}
		}
	}

	sealed class ImmediateModuleReader : ModuleReader {

		bool resolve_attributes;

		public ImmediateModuleReader (Image image)
			: base (image, ReadingMode.Immediate)
		{
		}

		protected override void ReadModule ()
		{
			this.module.Read (this.module, (module, reader) => {
				ReadModuleManifest (reader);
				ReadModule (module, resolve_attributes: true);
			});
		}

		public void ReadModule (ModuleDefinition module, bool resolve_attributes)
		{
			this.resolve_attributes = resolve_attributes;

			if (module.HasAssemblyReferences)
				Mixin.Read (module.AssemblyReferences);
			if (module.HasResources)
				Mixin.Read (module.Resources);
			if (module.HasModuleReferences)
				Mixin.Read (module.ModuleReferences);
			if (module.HasTypes)
				ReadTypes (module.Types);
			if (module.HasExportedTypes)
				Mixin.Read (module.ExportedTypes);

			ReadCustomAttributes (module);

			var assembly = module.Assembly;
			if (assembly == null)
				return;

			ReadCustomAttributes (assembly);
			ReadSecurityDeclarations (assembly);
		}

		void ReadTypes (Collection<TypeDefinition> types)
		{
			for (int i = 0; i < types.Count; i++)
				ReadType (types [i]);
		}

		void ReadType (TypeDefinition type)
		{
			ReadGenericParameters (type);

			if (type.HasInterfaces)
				ReadInterfaces (type);

			if (type.HasNestedTypes)
				ReadTypes (type.NestedTypes);

			if (type.HasLayoutInfo)
				Mixin.Read (type.ClassSize);

			if (type.HasFields)
				ReadFields (type);

			if (type.HasMethods)
				ReadMethods (type);

			if (type.HasProperties)
				ReadProperties (type);

			if (type.HasEvents)
				ReadEvents (type);

			ReadSecurityDeclarations (type);
			ReadCustomAttributes (type);
		}

		void ReadInterfaces (TypeDefinition type)
		{
			var interfaces = type.Interfaces;

			for (int i = 0; i < interfaces.Count; i++)
				ReadCustomAttributes (interfaces [i]);
		}

		void ReadGenericParameters (IGenericParameterProvider provider)
		{
			if (!provider.HasGenericParameters)
				return;

			var parameters = provider.GenericParameters;

			for (int i = 0; i < parameters.Count; i++) {
				var parameter = parameters [i];

				if (parameter.HasConstraints)
					ReadGenericParameterConstraints (parameter);

				ReadCustomAttributes (parameter);
			}
		}

		void ReadGenericParameterConstraints (GenericParameter parameter)
		{
			var constraints = parameter.Constraints;

			for (int i = 0; i < constraints.Count; i++)
				ReadCustomAttributes (constraints [i]);
		}

		void ReadSecurityDeclarations (ISecurityDeclarationProvider provider)
		{
			if (!provider.HasSecurityDeclarations)
				return;

			var security_declarations = provider.SecurityDeclarations;

			if (!resolve_attributes)
				return;

			for (int i = 0; i < security_declarations.Count; i++) {
				var security_declaration = security_declarations [i];

				Mixin.Read (security_declaration.SecurityAttributes);
			}
		}

		void ReadCustomAttributes (ICustomAttributeProvider provider)
		{
			if (!provider.HasCustomAttributes)
				return;

			var custom_attributes = provider.CustomAttributes;

			if (!resolve_attributes)
				return;

			for (int i = 0; i < custom_attributes.Count; i++) {
				var custom_attribute = custom_attributes [i];

				Mixin.Read (custom_attribute.ConstructorArguments);
			}
		}

		void ReadFields (TypeDefinition type)
		{
			var fields = type.Fields;

			for (int i = 0; i < fields.Count; i++) {
				var field = fields [i];

				if (field.HasConstant)
					Mixin.Read (field.Constant);

				if (field.HasLayoutInfo)
					Mixin.Read (field.Offset);

				if (field.RVA > 0)
					Mixin.Read (field.InitialValue);

				if (field.HasMarshalInfo)
					Mixin.Read (field.MarshalInfo);

				ReadCustomAttributes (field);
			}
		}

		void ReadMethods (TypeDefinition type)
		{
			var methods = type.Methods;

			for (int i = 0; i < methods.Count; i++) {
				var method = methods [i];

				ReadGenericParameters (method);

				if (method.HasParameters)
					ReadParameters (method);

				if (method.HasOverrides)
					Mixin.Read (method.Overrides);

				if (method.IsPInvokeImpl)
					Mixin.Read (method.PInvokeInfo);

				ReadSecurityDeclarations (method);
				ReadCustomAttributes (method);

				var return_type = method.MethodReturnType;
				if (return_type.HasConstant)
					Mixin.Read (return_type.Constant);

				if (return_type.HasMarshalInfo)
					Mixin.Read (return_type.MarshalInfo);

				ReadCustomAttributes (return_type);
			}
		}

		void ReadParameters (MethodDefinition method)
		{
			var parameters = method.Parameters;

			for (int i = 0; i < parameters.Count; i++) {
				var parameter = parameters [i];

				if (parameter.HasConstant)
					Mixin.Read (parameter.Constant);

				if (parameter.HasMarshalInfo)
					Mixin.Read (parameter.MarshalInfo);

				ReadCustomAttributes (parameter);
			}
		}

		void ReadProperties (TypeDefinition type)
		{
			var properties = type.Properties;

			for (int i = 0; i < properties.Count; i++) {
				var property = properties [i];

				Mixin.Read (property.GetMethod);

				if (property.HasConstant)
					Mixin.Read (property.Constant);

				ReadCustomAttributes (property);
			}
		}

		void ReadEvents (TypeDefinition type)
		{
			var events = type.Events;

			for (int i = 0; i < events.Count; i++) {
				var @event = events [i];

				Mixin.Read (@event.AddMethod);

				ReadCustomAttributes (@event);
			}
		}

		public override void ReadSymbols (ModuleDefinition module)
		{
			if (module.symbol_reader == null)
				return;

			ReadTypesSymbols (module.Types, module.symbol_reader);
		}

		void ReadTypesSymbols (Collection<TypeDefinition> types, ISymbolReader symbol_reader)
		{
			for (int i = 0; i < types.Count; i++) {
				var type = types [i];

				if (type.HasNestedTypes)
					ReadTypesSymbols (type.NestedTypes, symbol_reader);

				if (type.HasMethods)
					ReadMethodsSymbols (type, symbol_reader);
			}
		}

		void ReadMethodsSymbols (TypeDefinition type, ISymbolReader symbol_reader)
		{
			var methods = type.Methods;
			for (int i = 0; i < methods.Count; i++) {
				var method = methods [i];

				if (method.HasBody && method.token.RID != 0 && method.debug_info == null)
					method.debug_info = symbol_reader.Read (method);
			}
		}
	}

	sealed class DeferredModuleReader : ModuleReader {

		public DeferredModuleReader (Image image)
			: base (image, ReadingMode.Deferred)
		{
		}

		protected override void ReadModule ()
		{
			this.module.Read (this.module, (_, reader) => ReadModuleManifest (reader));
		}

		public override void ReadSymbols (ModuleDefinition module)
		{
		}
	}

	sealed class MetadataReader : ByteBuffer {

		readonly internal Image image;
		readonly internal ModuleDefinition module;
		readonly internal MetadataSystem metadata;

		internal CodeReader code;
		internal IGenericContext context;

		readonly MetadataReader metadata_reader;

		public MetadataReader (ModuleDefinition module)
			: base (module.Image.TableHeap.data)
		{
			this.image = module.Image;
			this.module = module;
			this.metadata = module.MetadataSystem;
			this.code = new CodeReader (this);
		}

		public MetadataReader (Image image, ModuleDefinition module, MetadataReader metadata_reader)
			: base (image.TableHeap.data)
		{
			this.image = image;
			this.module = module;
			this.metadata = module.MetadataSystem;
			this.metadata_reader = metadata_reader;
		}

		int GetCodedIndexSize (CodedIndex index)
		{
			return image.GetCodedIndexSize (index);
		}

		uint ReadByIndexSize (int size)
		{
			if (size == 4)
				return ReadUInt32 ();
			else
				return ReadUInt16 ();
		}

		byte [] ReadBlob ()
		{
			var blob_heap = image.BlobHeap;
			if (blob_heap == null) {
				position += 2;
				return Empty<byte>.Array;
			}

			return blob_heap.Read (ReadBlobIndex ());
		}

		byte [] ReadBlob (uint signature)
		{
			var blob_heap = image.BlobHeap;
			if (blob_heap == null)
				return Empty<byte>.Array;

			return blob_heap.Read (signature);
		}

		uint ReadBlobIndex ()
		{
			var blob_heap = image.BlobHeap;
			return ReadByIndexSize (blob_heap != null ? blob_heap.IndexSize : 2);
		}

		void GetBlobView (uint signature, out byte [] blob, out int index, out int count)
		{
			var blob_heap = image.BlobHeap;
			if (blob_heap == null) {
				blob = null;
				index = count = 0;
				return;
			}

			blob_heap.GetView (signature, out blob, out index, out count);
		}

		string ReadString ()
		{
			return image.StringHeap.Read (ReadByIndexSize (image.StringHeap.IndexSize));
		}

		uint ReadStringIndex ()
		{
			return ReadByIndexSize (image.StringHeap.IndexSize);
		}

		Guid ReadGuid ()
		{
			return image.GuidHeap.Read (ReadByIndexSize (image.GuidHeap.IndexSize));
		}

		uint ReadTableIndex (Table table)
		{
			return ReadByIndexSize (image.GetTableIndexSize (table));
		}

		MetadataToken ReadMetadataToken (CodedIndex index)
		{
			return index.GetMetadataToken (ReadByIndexSize (GetCodedIndexSize (index)));
		}

		int MoveTo (Table table)
		{
			var info = image.TableHeap [table];
			if (info.Length != 0)
				this.position = (int) info.Offset;

			return (int) info.Length;
		}

		bool MoveTo (Table table, uint row)
		{
			var info = image.TableHeap [table];
			var length = info.Length;
			if (length == 0 || row > length)
				return false;

			this.position = (int) (info.Offset + (info.RowSize * (row - 1)));
			return true;
		}

		public AssemblyNameDefinition ReadAssemblyNameDefinition ()
		{
			if (MoveTo (Table.Assembly) == 0)
				return null;

			var name = new AssemblyNameDefinition ();

			name.HashAlgorithm = (AssemblyHashAlgorithm) ReadUInt32 ();

			PopulateVersionAndFlags (name);

			name.PublicKey = ReadBlob ();

			PopulateNameAndCulture (name);

			return name;
		}

		public ModuleDefinition Populate (ModuleDefinition module)
		{
			if (MoveTo (Table.Module) == 0)
				return module;

			Advance (2); // Generation

			module.Name = ReadString ();
			module.Mvid = ReadGuid ();

			return module;
		}

		void InitializeAssemblyReferences ()
		{
			if (metadata.AssemblyReferences != null)
				return;

			int length = MoveTo (Table.AssemblyRef);
			var references = metadata.AssemblyReferences = new AssemblyNameReference [length];

			for (uint i = 0; i < length; i++) {
				var reference = new AssemblyNameReference ();
				reference.token = new MetadataToken (TokenType.AssemblyRef, i + 1);

				PopulateVersionAndFlags (reference);

				var key_or_token = ReadBlob ();

				if (reference.HasPublicKey)
					reference.PublicKey = key_or_token;
				else
					reference.PublicKeyToken = key_or_token;

				PopulateNameAndCulture (reference);

				reference.Hash = ReadBlob ();

				references [i] = reference;
			}
		}

		public Collection<AssemblyNameReference> ReadAssemblyReferences ()
		{
			InitializeAssemblyReferences ();

			var references = new Collection<AssemblyNameReference> (metadata.AssemblyReferences);
			if (module.IsWindowsMetadata ())
				module.Projections.AddVirtualReferences (references);

			return references;
		}

		public MethodDefinition ReadEntryPoint ()
		{
			if (module.Image.EntryPointToken == 0)
				return null;

			var token = new MetadataToken (module.Image.EntryPointToken);
			return GetMethodDefinition (token.RID);
		}

		public Collection<ModuleDefinition> ReadModules ()
		{
			var modules = new Collection<ModuleDefinition> (1);
			modules.Add (this.module);

			int length = MoveTo (Table.File);
			for (uint i = 1; i <= length; i++) {
				var attributes = (FileAttributes) ReadUInt32 ();
				var name = ReadString ();
				ReadBlobIndex ();

				if (attributes != FileAttributes.ContainsMetaData)
					continue;

				var parameters = new ReaderParameters {
					ReadingMode = module.ReadingMode,
					SymbolReaderProvider = module.SymbolReaderProvider,
					AssemblyResolver = module.AssemblyResolver
				};

				modules.Add (ModuleDefinition.ReadModule (
					GetModuleFileName (name), parameters));
			}

			return modules;
		}

		string GetModuleFileName (string name)
		{
			if (module.FileName == null)
				throw new NotSupportedException ();

			var path = Path.GetDirectoryName (module.FileName);
			return Path.Combine (path, name);
		}

		void InitializeModuleReferences ()
		{
			if (metadata.ModuleReferences != null)
				return;

			int length = MoveTo (Table.ModuleRef);
			var references = metadata.ModuleReferences = new ModuleReference [length];

			for (uint i = 0; i < length; i++) {
				var reference = new ModuleReference (ReadString ());
				reference.token = new MetadataToken (TokenType.ModuleRef, i + 1);

				references [i] = reference;
			}
		}

		public Collection<ModuleReference> ReadModuleReferences ()
		{
			InitializeModuleReferences ();

			return new Collection<ModuleReference> (metadata.ModuleReferences);
		}

		public bool HasFileResource ()
		{
			int length = MoveTo (Table.File);
			if (length == 0)
				return false;

			for (uint i = 1; i <= length; i++)
				if (ReadFileRecord (i).Col1 == FileAttributes.ContainsNoMetaData)
					return true;

			return false;
		}

		public Collection<Resource> ReadResources ()
		{
			int length = MoveTo (Table.ManifestResource);
			var resources = new Collection<Resource> (length);

			for (int i = 1; i <= length; i++) {
				var offset = ReadUInt32 ();
				var flags = (ManifestResourceAttributes) ReadUInt32 ();
				var name = ReadString ();
				var implementation = ReadMetadataToken (CodedIndex.Implementation);

				Resource resource;

				if (implementation.RID == 0) {
					resource = new EmbeddedResource (name, flags, offset, this);
				} else if (implementation.TokenType == TokenType.AssemblyRef) {
					resource = new AssemblyLinkedResource (name, flags) {
						Assembly = (AssemblyNameReference) GetTypeReferenceScope (implementation),
					};
				} else if (implementation.TokenType == TokenType.File) {
					var file_record = ReadFileRecord (implementation.RID);

					resource = new LinkedResource (name, flags) {
						File = file_record.Col2,
						hash = ReadBlob (file_record.Col3)
					};
				} else
					continue;

				resources.Add (resource);
			}

			return resources;
		}

		Row<FileAttributes, string, uint> ReadFileRecord (uint rid)
		{
			var position = this.position;

			if (!MoveTo (Table.File, rid))
				throw new ArgumentException ();

			var record = new Row<FileAttributes, string, uint> (
				(FileAttributes) ReadUInt32 (),
				ReadString (),
				ReadBlobIndex ());

			this.position = position;

			return record;
		}

		public byte [] GetManagedResource (uint offset)
		{
			return image.GetReaderAt (image.Resources.VirtualAddress, offset, (o, reader) => {
				reader.Advance ((int) o);
				return reader.ReadBytes (reader.ReadInt32 ());
			}) ?? Empty<byte>.Array;
		}

		void PopulateVersionAndFlags (AssemblyNameReference name)
		{
			name.Version = new Version (
				ReadUInt16 (),
				ReadUInt16 (),
				ReadUInt16 (),
				ReadUInt16 ());

			name.Attributes = (AssemblyAttributes) ReadUInt32 ();
		}

		void PopulateNameAndCulture (AssemblyNameReference name)
		{
			name.Name = ReadString ();
			name.Culture = ReadString ();
		}

		public TypeDefinitionCollection ReadTypes ()
		{
			InitializeTypeDefinitions ();
			var mtypes = metadata.Types;
			var type_count = mtypes.Length - metadata.NestedTypes.Count;
			var types = new TypeDefinitionCollection (module, type_count);

			for (int i = 0; i < mtypes.Length; i++) {
				var type = mtypes [i];
				if (IsNested (type.Attributes))
					continue;

				types.Add (type);
			}

			if (image.HasTable (Table.MethodPtr) || image.HasTable (Table.FieldPtr))
				CompleteTypes ();

			return types;
		}

		void CompleteTypes ()
		{
			var types = metadata.Types;

			for (int i = 0; i < types.Length; i++) {
				var type = types [i];

				Mixin.Read (type.Fields);
				Mixin.Read (type.Methods);
			}
		}

		void InitializeTypeDefinitions ()
		{
			if (metadata.Types != null)
				return;

			InitializeNestedTypes ();
			InitializeFields ();
			InitializeMethods ();

			int length = MoveTo (Table.TypeDef);
			var types = metadata.Types = new TypeDefinition [length];

			for (uint i = 0; i < length; i++) {
				if (types [i] != null)
					continue;

				types [i] = ReadType (i + 1);
			}

			if (module.IsWindowsMetadata ()) {
				for (uint i = 0; i < length; i++) {
					WindowsRuntimeProjections.Project (types [i]);
				}
			}
		}

		static bool IsNested (TypeAttributes attributes)
		{
			switch (attributes & TypeAttributes.VisibilityMask) {
			case TypeAttributes.NestedAssembly:
			case TypeAttributes.NestedFamANDAssem:
			case TypeAttributes.NestedFamily:
			case TypeAttributes.NestedFamORAssem:
			case TypeAttributes.NestedPrivate:
			case TypeAttributes.NestedPublic:
				return true;
			default:
				return false;
			}
		}

		public bool HasNestedTypes (TypeDefinition type)
		{
			Collection<uint> mapping;
			InitializeNestedTypes ();

			if (!metadata.TryGetNestedTypeMapping (type, out mapping))
				return false;

			return mapping.Count > 0;
		}

		public Collection<TypeDefinition> ReadNestedTypes (TypeDefinition type)
		{
			InitializeNestedTypes ();
			Collection<uint> mapping;
			if (!metadata.TryGetNestedTypeMapping (type, out mapping))
				return new MemberDefinitionCollection<TypeDefinition> (type);

			var nested_types = new MemberDefinitionCollection<TypeDefinition> (type, mapping.Count);

			for (int i = 0; i < mapping.Count; i++) {
				var nested_type = GetTypeDefinition (mapping [i]);

				if (nested_type != null)
					nested_types.Add (nested_type);
			}

			metadata.RemoveNestedTypeMapping (type);

			return nested_types;
		}

		void InitializeNestedTypes ()
		{
			if (metadata.NestedTypes != null)
				return;

			var length = MoveTo (Table.NestedClass);

			metadata.NestedTypes = new Dictionary<uint, Collection<uint>> (length);
			metadata.ReverseNestedTypes = new Dictionary<uint, uint> (length);

			if (length == 0)
				return;

			for (int i = 1; i <= length; i++) {
				var nested = ReadTableIndex (Table.TypeDef);
				var declaring = ReadTableIndex (Table.TypeDef);

				AddNestedMapping (declaring, nested);
			}
		}

		void AddNestedMapping (uint declaring, uint nested)
		{
			metadata.SetNestedTypeMapping (declaring, AddMapping (metadata.NestedTypes, declaring, nested));
			metadata.SetReverseNestedTypeMapping (nested, declaring);
		}

		static Collection<TValue> AddMapping<TKey, TValue> (Dictionary<TKey, Collection<TValue>> cache, TKey key, TValue value)
		{
			Collection<TValue> mapped;
			if (!cache.TryGetValue (key, out mapped)) {
				mapped = new Collection<TValue> ();
			}
			mapped.Add (value);
			return mapped;
		}

		TypeDefinition ReadType (uint rid)
		{
			if (!MoveTo (Table.TypeDef, rid))
				return null;

			var attributes = (TypeAttributes) ReadUInt32 ();
			var name = ReadString ();
			var @namespace = ReadString ();
			var type = new TypeDefinition (@namespace, name, attributes);
			type.token = new MetadataToken (TokenType.TypeDef, rid);
			type.scope = module;
			type.module = module;

			metadata.AddTypeDefinition (type);

			this.context = type;

			type.BaseType = GetTypeDefOrRef (ReadMetadataToken (CodedIndex.TypeDefOrRef));

			type.fields_range = ReadListRange (rid, Table.TypeDef, Table.Field);
			type.methods_range = ReadListRange (rid, Table.TypeDef, Table.Method);

			if (IsNested (attributes))
				type.DeclaringType = GetNestedTypeDeclaringType (type);

			return type;
		}

		TypeDefinition GetNestedTypeDeclaringType (TypeDefinition type)
		{
			uint declaring_rid;
			if (!metadata.TryGetReverseNestedTypeMapping (type, out declaring_rid))
				return null;

			metadata.RemoveReverseNestedTypeMapping (type);
			return GetTypeDefinition (declaring_rid);
		}

		Range ReadListRange (uint current_index, Table current, Table target)
		{
			var list = new Range ();

			var start = ReadTableIndex (target);
			if (start == 0)
				return list;

			uint next_index;
			var current_table = image.TableHeap [current];

			if (current_index == current_table.Length)
				next_index = image.TableHeap [target].Length + 1;
			else {
				var position = this.position;
				this.position += (int) (current_table.RowSize - image.GetTableIndexSize (target));
				next_index = ReadTableIndex (target);
				this.position = position;
			}

			list.Start = start;
			list.Length = next_index - start;

			return list;
		}

		public Row<short, int> ReadTypeLayout (TypeDefinition type)
		{
			InitializeTypeLayouts ();
			Row<ushort, uint> class_layout;
			var rid = type.token.RID;
			if (!metadata.ClassLayouts.TryGetValue (rid, out class_layout))
				return new Row<short, int> (Mixin.NoDataMarker, Mixin.NoDataMarker);

			type.PackingSize = (short) class_layout.Col1;
			type.ClassSize = (int) class_layout.Col2;

			metadata.ClassLayouts.Remove (rid);

			return new Row<short, int> ((short) class_layout.Col1, (int) class_layout.Col2);
		}

		void InitializeTypeLayouts ()
		{
			if (metadata.ClassLayouts != null)
				return;

			int length = MoveTo (Table.ClassLayout);

			var class_layouts = metadata.ClassLayouts = new Dictionary<uint, Row<ushort, uint>> (length);

			for (uint i = 0; i < length; i++) {
				var packing_size = ReadUInt16 ();
				var class_size = ReadUInt32 ();

				var parent = ReadTableIndex (Table.TypeDef);

				class_layouts.Add (parent, new Row<ushort, uint> (packing_size, class_size));
			}
		}

		public TypeReference GetTypeDefOrRef (MetadataToken token)
		{
			return (TypeReference) LookupToken (token);
		}

		public TypeDefinition GetTypeDefinition (uint rid)
		{
			InitializeTypeDefinitions ();

			var type = metadata.GetTypeDefinition (rid);
			if (type != null)
				return type;

			type = ReadTypeDefinition (rid);

			if (module.IsWindowsMetadata ())
				WindowsRuntimeProjections.Project (type);

			return type;
		}

		TypeDefinition ReadTypeDefinition (uint rid)
		{
			if (!MoveTo (Table.TypeDef, rid))
				return null;

			return ReadType (rid);
		}

		void InitializeTypeReferences ()
		{
			if (metadata.TypeReferences != null)
				return;

			metadata.TypeReferences = new TypeReference [image.GetTableLength (Table.TypeRef)];
		}

		public TypeReference GetTypeReference (string scope, string full_name)
		{
			InitializeTypeReferences ();

			var length = metadata.TypeReferences.Length;

			for (uint i = 1; i <= length; i++) {
				var type = GetTypeReference (i);

				if (type.FullName != full_name)
					continue;

				if (string.IsNullOrEmpty (scope))
					return type;

				if (type.Scope.Name == scope)
					return type;
			}

			return null;
		}

		TypeReference GetTypeReference (uint rid)
		{
			InitializeTypeReferences ();

			var type = metadata.GetTypeReference (rid);
			if (type != null)
				return type;

			return ReadTypeReference (rid);
		}

		TypeReference ReadTypeReference (uint rid)
		{
			if (!MoveTo (Table.TypeRef, rid))
				return null;

			TypeReference declaring_type = null;
			IMetadataScope scope;

			var scope_token = ReadMetadataToken (CodedIndex.ResolutionScope);

			var name = ReadString ();
			var @namespace = ReadString ();

			var type = new TypeReference (
				@namespace,
				name,
				module,
				null);

			type.token = new MetadataToken (TokenType.TypeRef, rid);

			metadata.AddTypeReference (type);

			if (scope_token.TokenType == TokenType.TypeRef) {
				if (scope_token.RID != rid) {
					declaring_type = GetTypeDefOrRef (scope_token);

					scope = declaring_type != null
						? declaring_type.Scope
						: module;
				} else // obfuscated typeref row pointing to self
					scope = module;
			} else
				scope = GetTypeReferenceScope (scope_token);

			type.scope = scope;
			type.DeclaringType = declaring_type;

			MetadataSystem.TryProcessPrimitiveTypeReference (type);

			if (type.Module.IsWindowsMetadata ())
				WindowsRuntimeProjections.Project (type);

			return type;
		}

		IMetadataScope GetTypeReferenceScope (MetadataToken scope)
		{
			if (scope.TokenType == TokenType.Module)
				return module;

			IMetadataScope[] scopes;

			switch (scope.TokenType) {
			case TokenType.AssemblyRef:
				InitializeAssemblyReferences ();
				scopes = metadata.AssemblyReferences;
				break;
			case TokenType.ModuleRef:
				InitializeModuleReferences ();
				scopes = metadata.ModuleReferences;
				break;
			default:
				throw new NotSupportedException ();
			}

			var index = scope.RID - 1;
			if (index < 0 || index >= scopes.Length)
				return null;

			return scopes [index];
		}

		public IEnumerable<TypeReference> GetTypeReferences ()
		{
			InitializeTypeReferences ();

			var length = image.GetTableLength (Table.TypeRef);

			var type_references = new TypeReference [length];

			for (uint i = 1; i <= length; i++)
				type_references [i - 1] = GetTypeReference (i);

			return type_references;
		}

		TypeReference GetTypeSpecification (uint rid)
		{
			if (!MoveTo (Table.TypeSpec, rid))
				return null;

			var reader = ReadSignature (ReadBlobIndex ());
			var type = reader.ReadTypeSignature ();
			if (type.token.RID == 0)
				type.token = new MetadataToken (TokenType.TypeSpec, rid);

			return type;
		}

		SignatureReader ReadSignature (uint signature)
		{
			return new SignatureReader (signature, this);
		}

		public bool HasInterfaces (TypeDefinition type)
		{
			InitializeInterfaces ();
			Collection<Row<uint, MetadataToken>> mapping;

			return metadata.TryGetInterfaceMapping (type, out mapping);
		}

		public InterfaceImplementationCollection ReadInterfaces (TypeDefinition type)
		{
			InitializeInterfaces ();
			Collection<Row<uint, MetadataToken>> mapping;

			if (!metadata.TryGetInterfaceMapping (type, out mapping))
				return new InterfaceImplementationCollection (type);

			var interfaces = new InterfaceImplementationCollection (type, mapping.Count);

			this.context = type;

			for (int i = 0; i < mapping.Count; i++) {
				interfaces.Add (
					new InterfaceImplementation (
						GetTypeDefOrRef (mapping [i].Col2),
						new MetadataToken(TokenType.InterfaceImpl, mapping [i].Col1)));
			}

			metadata.RemoveInterfaceMapping (type);

			return interfaces;
		}

		void InitializeInterfaces ()
		{
			if (metadata.Interfaces != null)
				return;

			int length = MoveTo (Table.InterfaceImpl);

			metadata.Interfaces = new Dictionary<uint, Collection<Row<uint, MetadataToken>>> (length);

			for (uint i = 1; i <= length; i++) {
				var type = ReadTableIndex (Table.TypeDef);
				var @interface = ReadMetadataToken (CodedIndex.TypeDefOrRef);

				AddInterfaceMapping (type, new Row<uint, MetadataToken> (i, @interface));
			}
		}

		void AddInterfaceMapping (uint type, Row<uint, MetadataToken> @interface)
		{
			metadata.SetInterfaceMapping (type, AddMapping (metadata.Interfaces, type, @interface));
		}

		public Collection<FieldDefinition> ReadFields (TypeDefinition type)
		{
			var fields_range = type.fields_range;
			if (fields_range.Length == 0)
				return new MemberDefinitionCollection<FieldDefinition> (type);

			var fields = new MemberDefinitionCollection<FieldDefinition> (type, (int) fields_range.Length);
			this.context = type;

			if (!MoveTo (Table.FieldPtr, fields_range.Start)) {
				if (!MoveTo (Table.Field, fields_range.Start))
					return fields;

				for (uint i = 0; i < fields_range.Length; i++)
					ReadField (fields_range.Start + i, fields);
			} else
				ReadPointers (Table.FieldPtr, Table.Field, fields_range, fields, ReadField);

			return fields;
		}

		void ReadField (uint field_rid, Collection<FieldDefinition> fields)
		{
			var attributes = (FieldAttributes) ReadUInt16 ();
			var name = ReadString ();
			var signature = ReadBlobIndex ();

			var field = new FieldDefinition (name, attributes, ReadFieldType (signature));
			field.token = new MetadataToken (TokenType.Field, field_rid);
			metadata.AddFieldDefinition (field);

			if (IsDeleted (field))
				return;

			fields.Add (field);

			if (module.IsWindowsMetadata ())
				WindowsRuntimeProjections.Project (field);
		}

		void InitializeFields ()
		{
			if (metadata.Fields != null)
				return;

			metadata.Fields = new FieldDefinition [image.GetTableLength (Table.Field)];
		}

		TypeReference ReadFieldType (uint signature)
		{
			var reader = ReadSignature (signature);

			const byte field_sig = 0x6;

			if (reader.ReadByte () != field_sig)
				throw new NotSupportedException ();

			return reader.ReadTypeSignature ();
		}

		public int ReadFieldRVA (FieldDefinition field)
		{
			InitializeFieldRVAs ();
			var rid = field.token.RID;

			RVA rva;
			if (!metadata.FieldRVAs.TryGetValue (rid, out rva))
				return 0;

			var size = GetFieldTypeSize (field.FieldType);

			if (size == 0 || rva == 0)
				return 0;

			metadata.FieldRVAs.Remove (rid);

			field.InitialValue = GetFieldInitializeValue (size, rva);

			return (int) rva;
		}

		byte [] GetFieldInitializeValue (int size, RVA rva)
		{
			return image.GetReaderAt (rva, size, (s, reader) => reader.ReadBytes (s)) ?? Empty<byte>.Array;
		}

		static int GetFieldTypeSize (TypeReference type)
		{
			int size = 0;

			switch (type.etype) {
			case ElementType.Boolean:
			case ElementType.U1:
			case ElementType.I1:
				size = 1;
				break;
			case ElementType.U2:
			case ElementType.I2:
			case ElementType.Char:
				size = 2;
				break;
			case ElementType.U4:
			case ElementType.I4:
			case ElementType.R4:
				size = 4;
				break;
			case ElementType.U8:
			case ElementType.I8:
			case ElementType.R8:
				size = 8;
				break;
			case ElementType.Ptr:
			case ElementType.FnPtr:
				size = IntPtr.Size;
				break;
			case ElementType.CModOpt:
			case ElementType.CModReqD:
				return GetFieldTypeSize (((IModifierType) type).ElementType);
			default:
				var field_type = type.Resolve ();
				if (field_type != null && field_type.HasLayoutInfo)
					size = field_type.ClassSize;

				break;
			}

			return size;
		}

		void InitializeFieldRVAs ()
		{
			if (metadata.FieldRVAs != null)
				return;

			int length = MoveTo (Table.FieldRVA);

			var field_rvas = metadata.FieldRVAs = new Dictionary<uint, uint> (length);

			for (int i = 0; i < length; i++) {
				var rva = ReadUInt32 ();
				var field = ReadTableIndex (Table.Field);

				field_rvas.Add (field, rva);
			}
		}

		public int ReadFieldLayout (FieldDefinition field)
		{
			InitializeFieldLayouts ();
			var rid = field.token.RID;
			uint offset;
			if (!metadata.FieldLayouts.TryGetValue (rid, out offset))
				return Mixin.NoDataMarker;

			metadata.FieldLayouts.Remove (rid);

			return (int) offset;
		}

		void InitializeFieldLayouts ()
		{
			if (metadata.FieldLayouts != null)
				return;

			int length = MoveTo (Table.FieldLayout);

			var field_layouts = metadata.FieldLayouts = new Dictionary<uint, uint> (length);

			for (int i = 0; i < length; i++) {
				var offset = ReadUInt32 ();
				var field = ReadTableIndex (Table.Field);

				field_layouts.Add (field, offset);
			}
		}

		public bool HasEvents (TypeDefinition type)
		{
			InitializeEvents ();

			Range range;
			if (!metadata.TryGetEventsRange (type, out range))
				return false;

			return range.Length > 0;
		}

		public Collection<EventDefinition> ReadEvents (TypeDefinition type)
		{
			InitializeEvents ();
			Range range;

			if (!metadata.TryGetEventsRange (type, out range))
				return new MemberDefinitionCollection<EventDefinition> (type);

			var events = new MemberDefinitionCollection<EventDefinition> (type, (int) range.Length);

			metadata.RemoveEventsRange (type);

			if (range.Length == 0)
				return events;

			this.context = type;

			if (!MoveTo (Table.EventPtr, range.Start)) {
				if (!MoveTo (Table.Event, range.Start))
					return events;

				for (uint i = 0; i < range.Length; i++)
					ReadEvent (range.Start + i, events);
			} else
				ReadPointers (Table.EventPtr, Table.Event, range, events, ReadEvent);

			return events;
		}

		void ReadEvent (uint event_rid, Collection<EventDefinition> events)
		{
			var attributes = (EventAttributes) ReadUInt16 ();
			var name = ReadString ();
			var event_type = GetTypeDefOrRef (ReadMetadataToken (CodedIndex.TypeDefOrRef));

			var @event = new EventDefinition (name, attributes, event_type);
			@event.token = new MetadataToken (TokenType.Event, event_rid);

			if (IsDeleted (@event))
				return;

			events.Add (@event);
		}

		void InitializeEvents ()
		{
			if (metadata.Events != null)
				return;

			int length = MoveTo (Table.EventMap);

			metadata.Events = new Dictionary<uint, Range> (length);

			for (uint i = 1; i <= length; i++) {
				var type_rid = ReadTableIndex (Table.TypeDef);
				Range events_range = ReadListRange (i, Table.EventMap, Table.Event);
				metadata.AddEventsRange (type_rid, events_range);
			}
		}

		public bool HasProperties (TypeDefinition type)
		{
			InitializeProperties ();

			Range range;
			if (!metadata.TryGetPropertiesRange (type, out range))
				return false;

			return range.Length > 0;
		}

		public Collection<PropertyDefinition> ReadProperties (TypeDefinition type)
		{
			InitializeProperties ();

			Range range;

			if (!metadata.TryGetPropertiesRange (type, out range))
				return new MemberDefinitionCollection<PropertyDefinition> (type);

			metadata.RemovePropertiesRange (type);

			var properties = new MemberDefinitionCollection<PropertyDefinition> (type, (int) range.Length);

			if (range.Length == 0)
				return properties;

			this.context = type;

			if (!MoveTo (Table.PropertyPtr, range.Start)) {
				if (!MoveTo (Table.Property, range.Start))
					return properties;
				for (uint i = 0; i < range.Length; i++)
					ReadProperty (range.Start + i, properties);
			} else
				ReadPointers (Table.PropertyPtr, Table.Property, range, properties, ReadProperty);

			return properties;
		}

		void ReadProperty (uint property_rid, Collection<PropertyDefinition> properties)
		{
			var attributes = (PropertyAttributes) ReadUInt16 ();
			var name = ReadString ();
			var signature = ReadBlobIndex ();

			var reader = ReadSignature (signature);
			const byte property_signature = 0x8;

			var calling_convention = reader.ReadByte ();

			if ((calling_convention & property_signature) == 0)
				throw new NotSupportedException ();

			var has_this = (calling_convention & 0x20) != 0;

			reader.ReadCompressedUInt32 (); // count

			var property = new PropertyDefinition (name, attributes, reader.ReadTypeSignature ());
			property.HasThis = has_this;
			property.token = new MetadataToken (TokenType.Property, property_rid);

			if (IsDeleted (property))
				return;

			properties.Add (property);
		}

		void InitializeProperties ()
		{
			if (metadata.Properties != null)
				return;

			int length = MoveTo (Table.PropertyMap);

			metadata.Properties = new Dictionary<uint, Range> (length);

			for (uint i = 1; i <= length; i++) {
				var type_rid = ReadTableIndex (Table.TypeDef);
				var properties_range = ReadListRange (i, Table.PropertyMap, Table.Property);
				metadata.AddPropertiesRange (type_rid, properties_range);
			}
		}

		MethodSemanticsAttributes ReadMethodSemantics (MethodDefinition method)
		{
			InitializeMethodSemantics ();
			Row<MethodSemanticsAttributes, MetadataToken> row;
			if (!metadata.Semantics.TryGetValue (method.token.RID, out row))
				return MethodSemanticsAttributes.None;

			var type = method.DeclaringType;

			switch (row.Col1) {
			case MethodSemanticsAttributes.AddOn:
				GetEvent (type, row.Col2).add_method = method;
				break;
			case MethodSemanticsAttributes.Fire:
				GetEvent (type, row.Col2).invoke_method = method;
				break;
			case MethodSemanticsAttributes.RemoveOn:
				GetEvent (type, row.Col2).remove_method = method;
				break;
			case MethodSemanticsAttributes.Getter:
				GetProperty (type, row.Col2).get_method = method;
				break;
			case MethodSemanticsAttributes.Setter:
				GetProperty (type, row.Col2).set_method = method;
				break;
			case MethodSemanticsAttributes.Other:
				switch (row.Col2.TokenType) {
				case TokenType.Event: {
					var @event = GetEvent (type, row.Col2);
					if (@event.other_methods == null)
						@event.other_methods = new Collection<MethodDefinition> ();

					@event.other_methods.Add (method);
					break;
				}
				case TokenType.Property: {
					var property = GetProperty (type, row.Col2);
					if (property.other_methods == null)
						property.other_methods = new Collection<MethodDefinition> ();

					property.other_methods.Add (method);

					break;
				}
				default:
					throw new NotSupportedException ();
				}
				break;
			default:
				throw new NotSupportedException ();
			}

			metadata.Semantics.Remove (method.token.RID);

			return row.Col1;
		}

		static EventDefinition GetEvent (TypeDefinition type, MetadataToken token)
		{
			if (token.TokenType != TokenType.Event)
				throw new ArgumentException ();

			return GetMember (type.Events, token);
		}

		static PropertyDefinition GetProperty (TypeDefinition type, MetadataToken token)
		{
			if (token.TokenType != TokenType.Property)
				throw new ArgumentException ();

			return GetMember (type.Properties, token);
		}

		static TMember GetMember<TMember> (Collection<TMember> members, MetadataToken token) where TMember : IMemberDefinition
		{
			for (int i = 0; i < members.Count; i++) {
				var member = members [i];
				if (member.MetadataToken == token)
					return member;
			}

			throw new ArgumentException ();
		}

		void InitializeMethodSemantics ()
		{
			if (metadata.Semantics != null)
				return;

			int length = MoveTo (Table.MethodSemantics);

			var semantics = metadata.Semantics = new Dictionary<uint, Row<MethodSemanticsAttributes, MetadataToken>> (0);

			for (uint i = 0; i < length; i++) {
				var attributes = (MethodSemanticsAttributes) ReadUInt16 ();
				var method_rid = ReadTableIndex (Table.Method);
				var association = ReadMetadataToken (CodedIndex.HasSemantics);

				semantics [method_rid] = new Row<MethodSemanticsAttributes, MetadataToken> (attributes, association);
			}
		}

		public void ReadMethods (PropertyDefinition property)
		{
			ReadAllSemantics (property.DeclaringType);
		}

		public void ReadMethods (EventDefinition @event)
		{
			ReadAllSemantics (@event.DeclaringType);
		}

		public void ReadAllSemantics (MethodDefinition method)
		{
			ReadAllSemantics (method.DeclaringType);
		}

		void ReadAllSemantics (TypeDefinition type)
		{
			var methods = type.Methods;
			for (int i = 0; i < methods.Count; i++) {
				var method = methods [i];
				if (method.sem_attrs_ready)
					continue;

				method.sem_attrs = ReadMethodSemantics (method);
				method.sem_attrs_ready = true;
			}
		}

		public Collection<MethodDefinition> ReadMethods (TypeDefinition type)
		{
			var methods_range = type.methods_range;
			if (methods_range.Length == 0)
				return new MemberDefinitionCollection<MethodDefinition> (type);

			var methods = new MemberDefinitionCollection<MethodDefinition> (type, (int) methods_range.Length);
			if (!MoveTo (Table.MethodPtr, methods_range.Start)) {
				if (!MoveTo (Table.Method, methods_range.Start))
					return methods;

				for (uint i = 0; i < methods_range.Length; i++)
					ReadMethod (methods_range.Start + i, methods);
			} else
				ReadPointers (Table.MethodPtr, Table.Method, methods_range, methods, ReadMethod);

			return methods;
		}

		void ReadPointers<TMember> (Table ptr, Table table, Range range, Collection<TMember> members, Action<uint, Collection<TMember>> reader)
			where TMember : IMemberDefinition
		{
			for (uint i = 0; i < range.Length; i++) {
				MoveTo (ptr, range.Start + i);

				var rid = ReadTableIndex (table);
				MoveTo (table, rid);

				reader (rid, members);
			}
		}

		static bool IsDeleted (IMemberDefinition member)
		{
			return member.IsSpecialName && member.Name == "_Deleted";
		}

		void InitializeMethods ()
		{
			if (metadata.Methods != null)
				return;

			metadata.Methods = new MethodDefinition [image.GetTableLength (Table.Method)];
		}

		void ReadMethod (uint method_rid, Collection<MethodDefinition> methods)
		{
			var method = new MethodDefinition ();
			method.rva = ReadUInt32 ();
			method.ImplAttributes = (MethodImplAttributes) ReadUInt16 ();
			method.Attributes = (MethodAttributes) ReadUInt16 ();
			method.Name = ReadString ();
			method.token = new MetadataToken (TokenType.Method, method_rid);

			if (IsDeleted (method))
				return;

			methods.Add (method); // attach method

			var signature = ReadBlobIndex ();
			var param_range = ReadListRange (method_rid, Table.Method, Table.Param);

			this.context = method;

			ReadMethodSignature (signature, method);
			metadata.AddMethodDefinition (method);

			if (param_range.Length != 0) {
				var position = base.position;
				ReadParameters (method, param_range);
				base.position = position;
			}

			if (module.IsWindowsMetadata ())
				WindowsRuntimeProjections.Project (method);
		}

		void ReadParameters (MethodDefinition method, Range param_range)
		{
			if (!MoveTo (Table.ParamPtr, param_range.Start)) {
				if (!MoveTo (Table.Param, param_range.Start))
					return;

				for (uint i = 0; i < param_range.Length; i++)
					ReadParameter (param_range.Start + i, method);
			} else
				ReadParameterPointers (method, param_range);
		}

		void ReadParameterPointers (MethodDefinition method, Range range)
		{
			for (uint i = 0; i < range.Length; i++) {
				MoveTo (Table.ParamPtr, range.Start + i);

				var rid = ReadTableIndex (Table.Param);

				MoveTo (Table.Param, rid);

				ReadParameter (rid, method);
			}
		}

		void ReadParameter (uint param_rid, MethodDefinition method)
		{
			var attributes = (ParameterAttributes) ReadUInt16 ();
			var sequence = ReadUInt16 ();
			var name = ReadString ();

			var parameter = sequence == 0
				? method.MethodReturnType.Parameter
				: method.Parameters [sequence - 1];

			parameter.token = new MetadataToken (TokenType.Param, param_rid);
			parameter.Name = name;
			parameter.Attributes = attributes;
		}

		void ReadMethodSignature (uint signature, IMethodSignature method)
		{
			var reader = ReadSignature (signature);
			reader.ReadMethodSignature (method);
		}

		public PInvokeInfo ReadPInvokeInfo (MethodDefinition method)
		{
			InitializePInvokes ();
			Row<PInvokeAttributes, uint, uint> row;

			var rid = method.token.RID;

			if (!metadata.PInvokes.TryGetValue (rid, out row))
				return null;

			metadata.PInvokes.Remove (rid);

			return new PInvokeInfo (
				row.Col1,
				image.StringHeap.Read (row.Col2),
				module.ModuleReferences [(int) row.Col3 - 1]);
		}

		void InitializePInvokes ()
		{
			if (metadata.PInvokes != null)
				return;

			int length = MoveTo (Table.ImplMap);

			var pinvokes = metadata.PInvokes = new Dictionary<uint, Row<PInvokeAttributes, uint, uint>> (length);

			for (int i = 1; i <= length; i++) {
				var attributes = (PInvokeAttributes) ReadUInt16 ();
				var method = ReadMetadataToken (CodedIndex.MemberForwarded);
				var name = ReadStringIndex ();
				var scope = ReadTableIndex (Table.File);

				if (method.TokenType != TokenType.Method)
					continue;

				pinvokes.Add (method.RID, new Row<PInvokeAttributes, uint, uint> (attributes, name, scope));
			}
		}

		public bool HasGenericParameters (IGenericParameterProvider provider)
		{
			InitializeGenericParameters ();

			Range [] ranges;
			if (!metadata.TryGetGenericParameterRanges (provider, out ranges))
				return false;

			return RangesSize (ranges) > 0;
		}

		public Collection<GenericParameter> ReadGenericParameters (IGenericParameterProvider provider)
		{
			InitializeGenericParameters ();

			Range [] ranges;
			if (!metadata.TryGetGenericParameterRanges (provider, out ranges))
				return new GenericParameterCollection (provider);

			metadata.RemoveGenericParameterRange (provider);

			var generic_parameters = new GenericParameterCollection (provider, RangesSize (ranges));

			for (int i = 0; i < ranges.Length; i++)
				ReadGenericParametersRange (ranges [i], provider, generic_parameters);

			return generic_parameters;
		}

		void ReadGenericParametersRange (Range range, IGenericParameterProvider provider, GenericParameterCollection generic_parameters)
		{
			if (!MoveTo (Table.GenericParam, range.Start))
				return;

			for (uint i = 0; i < range.Length; i++) {
				ReadUInt16 (); // index
				var flags = (GenericParameterAttributes) ReadUInt16 ();
				ReadMetadataToken (CodedIndex.TypeOrMethodDef);
				var name = ReadString ();

				var parameter = new GenericParameter (name, provider);
				parameter.token = new MetadataToken (TokenType.GenericParam, range.Start + i);
				parameter.Attributes = flags;

				generic_parameters.Add (parameter);
			}
		}

		void InitializeGenericParameters ()
		{
			if (metadata.GenericParameters != null)
				return;

			metadata.GenericParameters = InitializeRanges (
				Table.GenericParam, () => {
					Advance (4);
					var next = ReadMetadataToken (CodedIndex.TypeOrMethodDef);
					ReadStringIndex ();
					return next;
			});
		}

		Dictionary<MetadataToken, Range []> InitializeRanges (Table table, Func<MetadataToken> get_next)
		{
			int length = MoveTo (table);
			var ranges = new Dictionary<MetadataToken, Range []> (length);

			if (length == 0)
				return ranges;

			MetadataToken owner = MetadataToken.Zero;
			Range range = new Range (1, 0);

			for (uint i = 1; i <= length; i++) {
				var next = get_next ();

				if (i == 1) {
					owner = next;
					range.Length++;
				} else if (next != owner) {
					AddRange (ranges, owner, range);
					range = new Range (i, 1);
					owner = next;
				} else
					range.Length++;
			}

			AddRange (ranges, owner, range);

			return ranges;
		}

		static void AddRange (Dictionary<MetadataToken, Range []> ranges, MetadataToken owner, Range range)
		{
			if (owner.RID == 0)
				return;

			Range [] slots;
			if (!ranges.TryGetValue (owner, out slots)) {
				ranges.Add (owner, new [] { range });
				return;
			}

			ranges [owner] = slots.Add(range);
		}

		public bool HasGenericConstraints (GenericParameter generic_parameter)
		{
			InitializeGenericConstraints ();

			Collection<Row<uint, MetadataToken>> mapping;
			if (!metadata.TryGetGenericConstraintMapping (generic_parameter, out mapping))
				return false;

			return mapping.Count > 0;
		}

		public GenericParameterConst…