First pass at a branch with reduced memory usage; Keeps an open handle on the file, dispose your modules

6 files changed, 74 insertions, 67 deletions

diff --git a/Mono.Cecil.PE/BinaryStreamReader.cs b/Mono.Cecil.PE/BinaryStreamReader.cs
index ec2477c..77a8b44 100644
--- a/Mono.Cecil.PE/BinaryStreamReader.cs
+++ b/Mono.Cecil.PE/BinaryStreamReader.cs
@@ -33,17 +33,31 @@ namespace Mono.Cecil.PE {
 
 	class BinaryStreamReader : BinaryReader {
 
+		public int Position {
+			get { return (int) BaseStream.Position; }
+			set { BaseStream.Position = value; }
+		}
+
+		public int Length {
+			get { return (int) BaseStream.Length; }
+		}
+
 		public BinaryStreamReader (Stream stream)
 			: base (stream)
 		{
 		}
 
-		protected void Advance (int bytes)
+		public void Advance (int bytes)
 		{
 			BaseStream.Seek (bytes, SeekOrigin.Current);
 		}
 
-		protected DataDirectory ReadDataDirectory ()
+		public void MoveTo (uint position)
+		{
+			BaseStream.Seek (position, SeekOrigin.Begin);
+		}
+
+		public DataDirectory ReadDataDirectory ()
 		{
 			return new DataDirectory (ReadUInt32 (), ReadUInt32 ());
 		}
diff --git a/Mono.Cecil.PE/ByteBuffer.cs b/Mono.Cecil.PE/ByteBuffer.cs
index c7ae7ae..4f32c09 100644
--- a/Mono.Cecil.PE/ByteBuffer.cs
+++ b/Mono.Cecil.PE/ByteBuffer.cs
@@ -52,12 +52,6 @@ namespace Mono.Cecil.PE {
 			this.length = this.buffer.Length;
 		}
 
-		public void Reset (byte [] buffer)
-		{
-			this.buffer = buffer ?? Empty<byte>.Array;
-			this.length = this.buffer.Length;
-		}
-
 		public void Advance (int length)
 		{
 			position += length;
diff --git a/Mono.Cecil.PE/Image.cs b/Mono.Cecil.PE/Image.cs
index 9a04494..8971b13 100644
--- a/Mono.Cecil.PE/Image.cs
+++ b/Mono.Cecil.PE/Image.cs
@@ -27,8 +27,8 @@
 //
 
 using System;
+using System.IO;
 
-using Mono;
 using Mono.Cecil.Cil;
 using Mono.Cecil.Metadata;
 
@@ -36,12 +36,13 @@ using RVA = System.UInt32;
 
 namespace Mono.Cecil.PE {
 
-	sealed class Image {
+	sealed class Image : IDisposable {
+
+		public Stream Stream;
 
 		public ModuleKind Kind;
 		public TargetRuntime Runtime;
 		public TargetArchitecture Architecture;
-		public string FileName;
 
 		public Section [] Sections;
 
@@ -131,29 +132,42 @@ namespace Mono.Cecil.PE {
 			return null;
 		}
 
+		public BinaryStreamReader GetReaderAt (RVA rva)
+		{
+			var reader = new BinaryStreamReader (Stream);
+			reader.MoveTo (ResolveVirtualAddress (rva));
+			return reader;
+		}
+
 		public ImageDebugDirectory GetDebugHeader (out byte [] header)
 		{
-			var section = GetSectionAtVirtualAddress (Debug.VirtualAddress);
-			var buffer = new ByteBuffer (section.Data);
-			buffer.position = (int) (Debug.VirtualAddress - section.VirtualAddress);
+			var reader = GetReaderAt (Debug.VirtualAddress);
 
 			var directory = new ImageDebugDirectory {
-				Characteristics = buffer.ReadInt32 (),
-				TimeDateStamp = buffer.ReadInt32 (),
-				MajorVersion = buffer.ReadInt16 (),
-				MinorVersion = buffer.ReadInt16 (),
-				Type = buffer.ReadInt32 (),
-				SizeOfData = buffer.ReadInt32 (),
-				AddressOfRawData = buffer.ReadInt32 (),
-				PointerToRawData = buffer.ReadInt32 (),
+				Characteristics = reader.ReadInt32 (),
+				TimeDateStamp = reader.ReadInt32 (),
+				MajorVersion = reader.ReadInt16 (),
+				MinorVersion = reader.ReadInt16 (),
+				Type = reader.ReadInt32 (),
+				SizeOfData = reader.ReadInt32 (),
+				AddressOfRawData = reader.ReadInt32 (),
+				PointerToRawData = reader.ReadInt32 (),
 			};
 
-			buffer.position = (int) (directory.PointerToRawData - section.PointerToRawData);
+			reader = GetReaderAt ((uint) directory.AddressOfRawData);
+			header = reader.ReadBytes (directory.SizeOfData);
+			return directory;
+		}
 
-			header = new byte [directory.SizeOfData];
-			Buffer.BlockCopy (buffer.buffer, buffer.position, header, 0, header.Length);
+		~Image ()
+		{
+			if (Stream != null)
+				Stream.Dispose ();
+		}
 
-			return directory;
+		public void Dispose ()
+		{
+			Stream.Dispose ();
 		}
 	}
 }
diff --git a/Mono.Cecil.PE/ImageReader.cs b/Mono.Cecil.PE/ImageReader.cs
index 734b00a..1205e0b 100644
--- a/Mono.Cecil.PE/ImageReader.cs
+++ b/Mono.Cecil.PE/ImageReader.cs
@@ -42,12 +42,13 @@ namespace Mono.Cecil.PE {
 		DataDirectory cli;
 		DataDirectory metadata;
 
+		uint table_heap_offset;
+
 		public ImageReader (Stream stream)
 			: base (stream)
 		{
 			image = new Image ();
-
-			image.FileName = stream.GetFullyQualifiedName ();
+			image.Stream = stream;
 		}
 
 		void MoveTo (DataDirectory directory)
@@ -55,11 +56,6 @@ namespace Mono.Cecil.PE {
 			BaseStream.Position = image.ResolveVirtualAddress (directory.VirtualAddress);
 		}
 
-		void MoveTo (uint position)
-		{
-			BaseStream.Position = position;
-		}
-
 		void ReadImage ()
 		{
 			if (BaseStream.Length < 128)
@@ -275,31 +271,11 @@ namespace Mono.Cecil.PE {
 				Advance (16);
 
 				sections [i] = section;
-
-				ReadSectionData (section);
 			}
 
 			image.Sections = sections;
 		}
 
-		void ReadSectionData (Section section)
-		{
-			var position = BaseStream.Position;
-
-			MoveTo (section.PointerToRawData);
-
-			var length = (int) section.SizeOfRawData;
-			var data = new byte [length];
-			int offset = 0, read;
-
-			while ((read = Read (data, offset, length - offset)) > 0)
-				offset += read;
-
-			section.Data = data;
-
-			BaseStream.Position = position;
-		}
-
 		void ReadCLIHeader ()
 		{
 			MoveTo (cli);
@@ -362,39 +338,50 @@ namespace Mono.Cecil.PE {
 		void ReadMetadataStream (Section section)
 		{
 			// Offset		4
-			uint start = metadata.VirtualAddress - section.VirtualAddress + ReadUInt32 (); // relative to the section start
+			uint offset = metadata.VirtualAddress - section.VirtualAddress + ReadUInt32 (); // relative to the section start
 
 			// Size			4
 			uint size = ReadUInt32 ();
 
+			var data = ReadHeapData (offset, size);
+
 			var name = ReadAlignedString (16);
 			switch (name) {
 			case "#~":
 			case "#-":
-				image.TableHeap = new TableHeap (section, start, size);
+				image.TableHeap = new TableHeap (data);
+				table_heap_offset = offset;
 				break;
 			case "#Strings":
-				image.StringHeap = new StringHeap (section, start, size);
+				image.StringHeap = new StringHeap (data);
 				break;
 			case "#Blob":
-				image.BlobHeap = new BlobHeap (section, start, size);
+				image.BlobHeap = new BlobHeap (data);
 				break;
 			case "#GUID":
-				image.GuidHeap = new GuidHeap (section, start, size);
+				image.GuidHeap = new GuidHeap (data);
 				break;
 			case "#US":
-				image.UserStringHeap = new UserStringHeap (section, start, size);
+				image.UserStringHeap = new UserStringHeap (data);
 				break;
 			}
 		}
 
+		byte [] ReadHeapData (uint offset, uint size)
+		{
+			var position = BaseStream.Position;
+			MoveTo (offset + image.MetadataSection.PointerToRawData);
+			var data = ReadBytes ((int) size);
+			BaseStream.Position = position;
+
+			return data;
+		}
+
 		void ReadTableHeap ()
 		{
 			var heap = image.TableHeap;
 
-			uint start = heap.Section.PointerToRawData;
-
-			MoveTo (heap.Offset + start);
+			MoveTo (table_heap_offset + image.MetadataSection.PointerToRawData);
 
 			// Reserved			4
 			// MajorVersion		1
@@ -447,7 +434,7 @@ namespace Mono.Cecil.PE {
 
 		void ComputeTableInformations ()
 		{
-			uint offset = (uint) BaseStream.Position - image.MetadataSection.PointerToRawData; // header
+			uint offset = (uint) BaseStream.Position - table_heap_offset - image.MetadataSection.PointerToRawData; // header
 
 			int stridx_size = image.StringHeap.IndexSize;
 			int blobidx_size = image.BlobHeap != null ? image.BlobHeap.IndexSize : 2;
diff --git a/Mono.Cecil.PE/ImageWriter.cs b/Mono.Cecil.PE/ImageWriter.cs
index 6f921d9..b5cdbe9 100644
--- a/Mono.Cecil.PE/ImageWriter.cs
+++ b/Mono.Cecil.PE/ImageWriter.cs
@@ -95,9 +95,8 @@ namespace Mono.Cecil.PE {
 			if (rsrc == null)
 				return;
 
-			var raw_resources = new byte [rsrc.Data.Length];
-			Buffer.BlockCopy (rsrc.Data, 0, raw_resources, 0, rsrc.Data.Length);
-			win32_resources = new ByteBuffer (raw_resources);
+			var reader = module.Image.GetReaderAt (rsrc.VirtualAddress);
+			win32_resources = new ByteBuffer (reader.ReadBytes ((int) rsrc.SizeOfRawData));
 		}
 
 		Section GetImageResourceSection ()
diff --git a/Mono.Cecil.PE/Section.cs b/Mono.Cecil.PE/Section.cs
index 6a4c7ba..938d1a2 100644
--- a/Mono.Cecil.PE/Section.cs
+++ b/Mono.Cecil.PE/Section.cs
@@ -38,6 +38,5 @@ namespace Mono.Cecil.PE {
 		public uint VirtualSize;
 		public uint SizeOfRawData;
 		public uint PointerToRawData;
-		public byte [] Data;
 	}
 }