Only keep the table heap in memory; read the other heaps from the underlying stream

7 files changed, 59 insertions, 66 deletions

diff --git a/Mono.Cecil.Metadata/BlobHeap.cs b/Mono.Cecil.Metadata/BlobHeap.cs
index 2488569..ecbe9c2 100644
--- a/Mono.Cecil.Metadata/BlobHeap.cs
+++ b/Mono.Cecil.Metadata/BlobHeap.cs
@@ -26,30 +26,23 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
-using System;
+using Mono.Cecil.PE;
 
 namespace Mono.Cecil.Metadata {
 
 	sealed class BlobHeap : Heap {
 
-		public BlobHeap (byte [] data)
-			: base (data)
+		public BlobHeap (Image image, uint offset, uint size)
+			: base (image, offset, size)
 		{
 		}
 
 		public byte [] Read (uint index)
 		{
-			if (index == 0 || index > this.data.Length - 1)
+			if (index == 0 || index > Size - 1)
 				return Empty<byte>.Array;
 
-			int position = (int) index;
-			int length = (int) data.ReadCompressedUInt32 (ref position);
-
-			var buffer = new byte [length];
-
-			Buffer.BlockCopy (data, position, buffer, 0, length);
-
-			return buffer;
+			return ReadAt (index, reader => reader.ReadBytes ((int) reader.ReadCompressedUInt32 ()));
 		}
 	}
 }
diff --git a/Mono.Cecil.Metadata/GuidHeap.cs b/Mono.Cecil.Metadata/GuidHeap.cs
index 4199af1..996606f 100644
--- a/Mono.Cecil.Metadata/GuidHeap.cs
+++ b/Mono.Cecil.Metadata/GuidHeap.cs
@@ -27,13 +27,14 @@
 //
 
 using System;
+using Mono.Cecil.PE;
 
 namespace Mono.Cecil.Metadata {
 
 	sealed class GuidHeap : Heap {
 
-		public GuidHeap (byte [] data)
-			: base (data)
+		public GuidHeap (Image image, uint offset, uint size)
+			: base (image, offset, size)
 		{
 		}
 
@@ -44,13 +45,9 @@ namespace Mono.Cecil.Metadata {
 
 			const int guid_size = 16;
 
-			var buffer = new byte [guid_size];
-
 			index--;
 
-			Buffer.BlockCopy (this.data, (int) index, buffer, 0, guid_size);
-
-			return new Guid (buffer);
+			return ReadAt (index, reader => new Guid (reader.ReadBytes (guid_size)));
 		}
 	}
 }
diff --git a/Mono.Cecil.Metadata/Heap.cs b/Mono.Cecil.Metadata/Heap.cs
index 715e59b..afa6d7d 100644
--- a/Mono.Cecil.Metadata/Heap.cs
+++ b/Mono.Cecil.Metadata/Heap.cs
@@ -26,17 +26,29 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
+using System;
+using Mono.Cecil.PE;
+
 namespace Mono.Cecil.Metadata {
 
 	abstract class Heap {
 
 		public int IndexSize;
 
-		internal byte [] data;
+		public readonly Image Image;
+		public readonly uint Offset;
+		public readonly uint Size;
+
+		protected Heap (Image image, uint offset, uint size)
+		{
+			this.Image = image;
+			this.Offset = offset;
+			this.Size = size;
+		}
 
-		protected Heap (byte [] data)
+		public TRet ReadAt<TRet> (uint index, Func<BinaryStreamReader, TRet> read)
 		{
-			this.data = data;
+			return Image.ReadAt(Image.MetadataSection.VirtualAddress, reader => { reader.Advance ((int)(Offset + index)); return read(reader); });
 		}
 	}
 }
diff --git a/Mono.Cecil.Metadata/StringHeap.cs b/Mono.Cecil.Metadata/StringHeap.cs
index f195535..c37b4fa 100644
--- a/Mono.Cecil.Metadata/StringHeap.cs
+++ b/Mono.Cecil.Metadata/StringHeap.cs
@@ -26,18 +26,19 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
-using System;
 using System.Collections.Generic;
 using System.Text;
 
+using Mono.Cecil.PE;
+
 namespace Mono.Cecil.Metadata {
 
 	class StringHeap : Heap {
 
 		readonly Dictionary<uint, string> strings = new Dictionary<uint, string> ();
 
-		public StringHeap (byte [] data)
-			: base (data)
+		public StringHeap (Image image, uint offset, uint size)
+			: base (image, offset, size)
 		{
 		}
 
@@ -50,7 +51,7 @@ namespace Mono.Cecil.Metadata {
 			if (strings.TryGetValue (index, out @string))
 				return @string;
 
-			if (index > data.Length - 1)
+			if (index > Size - 1)
 				return string.Empty;
 
 			@string = ReadStringAt (index);
@@ -62,17 +63,20 @@ namespace Mono.Cecil.Metadata {
 
 		protected virtual string ReadStringAt (uint index)
 		{
-			int length = 0;
-			int start = (int) index;
+			return ReadAt (index, reader => {
+				int length = 0;
+				var start = reader.Position;
 
-			for (int i = start; ; i++) {
-				if (data [i] == 0)
-					break;
+				for (int i = 0; ; i++) {
+					if (reader.ReadByte () == 0)
+						break;
 
-				length++;
-			}
+					length++;
+				}
 
-			return Encoding.UTF8.GetString (data, start, length);
+				reader.Position = start;
+				return Encoding.UTF8.GetString (reader.ReadBytes (length), 0, length);
+			});
 		}
 	}
 }
diff --git a/Mono.Cecil.Metadata/TableHeap.cs b/Mono.Cecil.Metadata/TableHeap.cs
index 25a2ccc..af6b772 100644
--- a/Mono.Cecil.Metadata/TableHeap.cs
+++ b/Mono.Cecil.Metadata/TableHeap.cs
@@ -98,9 +98,12 @@ namespace Mono.Cecil.Metadata {
 			get { return Tables [(int) table]; }
 		}
 
-		public TableHeap (byte [] data)
-			: base (data)
+		internal byte [] data;
+
+		public TableHeap (Image image, uint offset, uint size, byte [] data)
+			: base (image, offset, size)
 		{
+			this.data = data;
 		}
 
 		public bool HasTable (Table table)
diff --git a/Mono.Cecil.Metadata/UserStringHeap.cs b/Mono.Cecil.Metadata/UserStringHeap.cs
index 7046eff..b33eea8 100644
--- a/Mono.Cecil.Metadata/UserStringHeap.cs
+++ b/Mono.Cecil.Metadata/UserStringHeap.cs
@@ -26,29 +26,33 @@
 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 
+using Mono.Cecil.PE;
+
 namespace Mono.Cecil.Metadata {
 
 	sealed class UserStringHeap : StringHeap {
 
-		public UserStringHeap (byte [] data)
-			: base (data)
+		public UserStringHeap (Image image, uint offset, uint size)
+			: base (image, offset, size)
 		{
 		}
 
 		protected override string ReadStringAt (uint index)
 		{
-			int start = (int) index;
+			return ReadAt (index, reader => {
+				uint length = (uint) (reader.ReadCompressedUInt32 () & ~1);
+				var data = reader.ReadBytes ((int) length);
 
-			uint length = (uint) (data.ReadCompressedUInt32 (ref start) & ~1);
-			if (length < 1)
-				return string.Empty;
+				if (length < 1)
+					return string.Empty;
 
-			var chars = new char [length / 2];
+				var chars = new char [length / 2];
 
-			for (int i = start, j = 0; i < start + length; i += 2)
-				chars [j++] = (char) (data [i] | (data [i + 1] << 8));
+				for (int i = 0, j = 0; i < length; i += 2)
+					chars [j++] = (char) (data [i] | (data [i + 1] << 8));
 
-			return new string (chars);
+				return new string (chars);
+			});
 		}
 	}
 }
diff --git a/Mono.Cecil.Metadata/Utilities.cs b/Mono.Cecil.Metadata/Utilities.cs
index d752b24..4c5a6bf 100644
--- a/Mono.Cecil.Metadata/Utilities.cs
+++ b/Mono.Cecil.Metadata/Utilities.cs
@@ -34,26 +34,6 @@ namespace Mono.Cecil {
 
 	static partial class Mixin {
 
-		public static uint ReadCompressedUInt32 (this byte [] data, ref int position)
-		{
-			uint integer;
-			if ((data [position] & 0x80) == 0) {
-				integer = data [position];
-				position++;
-			} else if ((data [position] & 0x40) == 0) {
-				integer = (uint) (data [position] & ~0x80) << 8;
-				integer |= data [position + 1];
-				position += 2;
-			} else {
-				integer = (uint) (data [position] & ~0xc0) << 24;
-				integer |= (uint) data [position + 1] << 16;
-				integer |= (uint) data [position + 2] << 8;
-				integer |= (uint) data [position + 3];
-				position += 4;
-			}
-			return integer;
-		}
-
 		public static MetadataToken GetMetadataToken (this CodedIndex self, uint data)
 		{
 			uint rid;