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Adds support for compressed QCOW and QCOW2 images, closes #72.

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This commit is contained in:
Natalia Portillo
2016-09-21 03:32:12 +01:00
parent 85fd3b5900
commit d95785eec1
3 changed files with 75 additions and 23 deletions
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45
DiscImageChef.DiscImages/QCOW.cs
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@@ -37,6 +37,8 @@ using System.Runtime.InteropServices;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;
using SharpCompress.Compressor;
using SharpCompress.Compressor.Deflate;
namespace DiscImageChef.ImagePlugins
{
@@ -342,21 +344,44 @@ namespace DiscImageChef.ImagePlugins
if(offset != 0)
{
if((offset & QCowCompressed) == QCowCompressed)
throw new NotImplementedException("Compressed images not yet supported.");
byte[] cluster;
if(!clusterCache.TryGetValue(offset, out cluster))
{
cluster = new byte[clusterSize];
imageStream.Seek((long)offset, SeekOrigin.Begin);
imageStream.Read(cluster, 0, clusterSize);
if((offset & QCowCompressed) == QCowCompressed)
{
ulong compSizeMask = 0;
ulong offMask = 0;
if(clusterCache.Count >= maxClusterCache)
clusterCache.Clear();
compSizeMask = (ulong)(1 << qHdr.cluster_bits) - 1;
compSizeMask <<= 63 - qHdr.cluster_bits;
offMask = (~compSizeMask) ^ QCowCompressed;
clusterCache.Add(offset, cluster);
}
ulong realOff = offset & offMask;
ulong compSize = (offset & compSizeMask) >> (63 - qHdr.cluster_bits);
byte[] zCluster = new byte[compSize];
imageStream.Seek((long)realOff, SeekOrigin.Begin);
imageStream.Read(zCluster, 0, (int)compSize);
DeflateStream zStream = new DeflateStream(new MemoryStream(zCluster), CompressionMode.Decompress);
cluster = new byte[clusterSize];
int read = zStream.Read(cluster, 0, clusterSize);
if(read != clusterSize)
throw new IOException(string.Format("Unable to decompress cluster, expected {0} bytes got {1}", clusterSize, read));
}
else
{
cluster = new byte[clusterSize];
imageStream.Seek((long)offset, SeekOrigin.Begin);
imageStream.Read(cluster, 0, clusterSize);
}
if(clusterCache.Count >= maxClusterCache)
clusterCache.Clear();
clusterCache.Add(offset, cluster);
}
Array.Copy(cluster, (int)(byteAddress & sectorMask), sector, 0, 512);
}