From 805633466e25a97301a3ebcca9499adbd1edbc94 Mon Sep 17 00:00:00 2001
From: Natalia Portillo <claunia@claunia.com>
Date: Fri, 15 Mar 2019 22:46:12 +0000
Subject: [PATCH] Use new marshaller in QEMU Copy-On-Write v2 disk image.

---
 DiscImageChef.DiscImages/QCOW2/Read.cs  | 14 ++++++--------
 DiscImageChef.DiscImages/QCOW2/Write.cs |  9 ++++++---
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/DiscImageChef.DiscImages/QCOW2/Read.cs b/DiscImageChef.DiscImages/QCOW2/Read.cs
index ec8dfd75d..d7339e76e 100644
--- a/DiscImageChef.DiscImages/QCOW2/Read.cs
+++ b/DiscImageChef.DiscImages/QCOW2/Read.cs
@@ -33,14 +33,15 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Runtime.InteropServices;
 using DiscImageChef.CommonTypes;
 using DiscImageChef.CommonTypes.Enums;
 using DiscImageChef.CommonTypes.Exceptions;
 using DiscImageChef.CommonTypes.Interfaces;
 using DiscImageChef.Console;
-using DiscImageChef.Helpers;
 using SharpCompress.Compressors;
 using SharpCompress.Compressors.Deflate;
+using Marshal = DiscImageChef.Helpers.Marshal;
 
 namespace DiscImageChef.DiscImages
 {
@@ -116,11 +117,9 @@ namespace DiscImageChef.DiscImages
             byte[] l1TableB = new byte[qHdr.l1_size * 8];
             stream.Seek((long)qHdr.l1_table_offset, SeekOrigin.Begin);
             stream.Read(l1TableB, 0, (int)qHdr.l1_size * 8);
-            l1Table = new ulong[qHdr.l1_size];
-            // TODO: Optimize this
+            l1Table = MemoryMarshal.Cast<byte, ulong>(l1TableB).ToArray();
             DicConsole.DebugWriteLine("QCOW plugin", "Reading L1 table");
-            for(long i = 0; i < l1Table.LongLength; i++)
-                l1Table[i] = BigEndianBitConverter.ToUInt64(l1TableB, (int)(i * 8));
+            for(long i = 0; i < l1Table.LongLength; i++) l1Table[i] = Swapping.Swap(l1Table[i]);
 
             l1Mask = 0;
             int c = 0;
@@ -197,13 +196,12 @@ namespace DiscImageChef.DiscImages
 
             if(!l2TableCache.TryGetValue(l1Off, out ulong[] l2Table))
             {
-                l2Table = new ulong[l2Size];
                 imageStream.Seek((long)(l1Table[l1Off] & QCOW_FLAGS_MASK), SeekOrigin.Begin);
                 byte[] l2TableB = new byte[l2Size * 8];
                 imageStream.Read(l2TableB, 0, l2Size * 8);
                 DicConsole.DebugWriteLine("QCOW plugin", "Reading L2 table #{0}", l1Off);
-                for(long i = 0; i < l2Table.LongLength; i++)
-                    l2Table[i] = BigEndianBitConverter.ToUInt64(l2TableB, (int)(i * 8));
+                l2Table = MemoryMarshal.Cast<byte, ulong>(l2TableB).ToArray();
+                for(long i = 0; i < l2Table.LongLength; i++) l2Table[i] = Swapping.Swap(l2Table[i]);
 
                 if(l2TableCache.Count >= maxL2TableCache) l2TableCache.Clear();
 
diff --git a/DiscImageChef.DiscImages/QCOW2/Write.cs b/DiscImageChef.DiscImages/QCOW2/Write.cs
index 110b543d4..b504bf849 100644
--- a/DiscImageChef.DiscImages/QCOW2/Write.cs
+++ b/DiscImageChef.DiscImages/QCOW2/Write.cs
@@ -34,11 +34,12 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using DiscImageChef.CommonTypes;
 using DiscImageChef.CommonTypes.Enums;
 using DiscImageChef.CommonTypes.Structs;
-using DiscImageChef.Helpers;
 using Schemas;
+using Marshal = DiscImageChef.Helpers.Marshal;
 
 namespace DiscImageChef.DiscImages
 {
@@ -317,8 +318,10 @@ namespace DiscImageChef.DiscImages
                 writingStream.Write(BigEndianBitConverter.GetBytes(refCountTable[i]), 0, 8);
 
             writingStream.Seek((long)qHdr.l1_table_offset, SeekOrigin.Begin);
-            for(long i = 0; i < l1Table.LongLength; i++)
-                writingStream.Write(BigEndianBitConverter.GetBytes(l1Table[i]), 0, 8);
+            for(long i = 0; i < l1Table.LongLength; i++) l1Table[i] = Swapping.Swap(l1Table[i]);
+            byte[] l1TableB =
+                MemoryMarshal.Cast<ulong, byte>(l1Table).ToArray();
+            writingStream.Write(l1TableB, 0, l1TableB.Length);
 
             writingStream.Flush();
             writingStream.Close();