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Aaru/Aaru.Images/QED/Read.cs
Natalia Portillo 828c1e3da0 [Aaru.Images] Introduced constants for module names 
Introduces constant fields for respective debug module names, replacing the hardcoded ones.
This is done to standardize the naming convention, reduce redundancy and potentially avoid any typos or name mismatches across the project.
This change makes the code more maintainable and easier to update in case module names need to be changed.
2023-10-03 18:50:20 +01:00

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// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename : Read.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
// Reads QEMU Enhanced Disk images.
//
// --[ License ] --------------------------------------------------------------
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2023 Natalia Portillo
// ****************************************************************************/
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Console;
using Aaru.Helpers;
using Marshal = Aaru.Helpers.Marshal;
namespace Aaru.DiscImages;
public sealed partial class Qed
{
/// <inheritdoc />
public ErrorNumber Open(IFilter imageFilter)
{
Stream stream = imageFilter.GetDataForkStream();
stream.Seek(0, SeekOrigin.Begin);
if(stream.Length < 512)
return ErrorNumber.InvalidArgument;
byte[] qHdrB = new byte[68];
stream.EnsureRead(qHdrB, 0, 68);
_qHdr = Marshal.SpanToStructureLittleEndian<QedHeader>(qHdrB);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.magic = 0x{0:X8}", _qHdr.magic);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.cluster_size = {0}", _qHdr.cluster_size);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.table_size = {0}", _qHdr.table_size);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.header_size = {0}", _qHdr.header_size);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.features = {0}", _qHdr.features);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.compat_features = {0}", _qHdr.compat_features);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.autoclear_features = {0}", _qHdr.autoclear_features);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.l1_table_offset = {0}", _qHdr.l1_table_offset);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.image_size = {0}", _qHdr.image_size);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.backing_file_offset = {0}", _qHdr.backing_file_offset);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.backing_file_size = {0}", _qHdr.backing_file_size);
if(_qHdr.image_size <= 1)
{
AaruConsole.ErrorWriteLine(Localization.Image_size_is_too_small);
return ErrorNumber.InvalidArgument;
}
if(!IsPowerOfTwo(_qHdr.cluster_size))
{
AaruConsole.ErrorWriteLine(Localization.Cluster_size_must_be_a_power_of_2);
return ErrorNumber.InvalidArgument;
}
if(_qHdr.cluster_size is < 4096 or > 67108864)
{
AaruConsole.ErrorWriteLine(Localization.Cluster_size_must_be_between_4_Kbytes_and_64_Mbytes);
return ErrorNumber.InvalidArgument;
}
if(!IsPowerOfTwo(_qHdr.table_size))
{
AaruConsole.ErrorWriteLine(Localization.Table_size_must_be_a_power_of_2);
return ErrorNumber.InvalidArgument;
}
if(_qHdr.table_size is < 1 or > 16)
{
AaruConsole.ErrorWriteLine(Localization.Table_size_must_be_between_1_and_16_clusters);
return ErrorNumber.InvalidArgument;
}
if((_qHdr.features & QED_FEATURE_MASK) > 0)
{
AaruConsole.ErrorWriteLine(string.Format(Localization.Image_uses_unknown_incompatible_features_0,
_qHdr.features & QED_FEATURE_MASK));
return ErrorNumber.InvalidArgument;
}
if((_qHdr.features & QED_FEATURE_BACKING_FILE) == QED_FEATURE_BACKING_FILE)
{
AaruConsole.ErrorWriteLine(Localization.Differencing_images_not_yet_supported);
return ErrorNumber.NotImplemented;
}
_clusterSectors = _qHdr.cluster_size / 512;
_tableSize = _qHdr.cluster_size * _qHdr.table_size / 8;
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.clusterSectors = {0}", _clusterSectors);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.tableSize = {0}", _tableSize);
byte[] l1TableB = new byte[_tableSize * 8];
stream.Seek((long)_qHdr.l1_table_offset, SeekOrigin.Begin);
stream.EnsureRead(l1TableB, 0, (int)_tableSize * 8);
AaruConsole.DebugWriteLine(MODULE_NAME, Localization.Reading_L1_table);
_l1Table = MemoryMarshal.Cast<byte, ulong>(l1TableB).ToArray();
_l1Mask = 0;
int c = 0;
_clusterBits = Ctz32(_qHdr.cluster_size);
_l2Mask = (_tableSize - 1) << _clusterBits;
_l1Shift = _clusterBits + Ctz32(_tableSize);
for(int i = 0; i < 64; i++)
{
_l1Mask <<= 1;
if(c >= 64 - _l1Shift)
continue;
_l1Mask += 1;
c++;
}
_sectorMask = 0;
for(int i = 0; i < _clusterBits; i++)
_sectorMask = (_sectorMask << 1) + 1;
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.clusterBits = {0}", _clusterBits);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.l1Mask = {0:X}", _l1Mask);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.l1Shift = {0}", _l1Shift);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.l2Mask = {0:X}", _l2Mask);
AaruConsole.DebugWriteLine(MODULE_NAME, "qHdr.sectorMask = {0:X}", _sectorMask);
_maxL2TableCache = MAX_CACHE_SIZE / _tableSize;
_maxClusterCache = MAX_CACHE_SIZE / _qHdr.cluster_size;
_imageStream = stream;
_sectorCache = new Dictionary<ulong, byte[]>();
_l2TableCache = new Dictionary<ulong, ulong[]>();
_clusterCache = new Dictionary<ulong, byte[]>();
_imageInfo.CreationTime = imageFilter.CreationTime;
_imageInfo.LastModificationTime = imageFilter.LastWriteTime;
_imageInfo.MediaTitle = Path.GetFileNameWithoutExtension(imageFilter.Filename);
_imageInfo.Sectors = _qHdr.image_size / 512;
_imageInfo.SectorSize = 512;
_imageInfo.MetadataMediaType = MetadataMediaType.BlockMedia;
_imageInfo.MediaType = MediaType.GENERIC_HDD;
_imageInfo.ImageSize = _qHdr.image_size;
_imageInfo.Cylinders = (uint)(_imageInfo.Sectors / 16 / 63);
_imageInfo.Heads = 16;
_imageInfo.SectorsPerTrack = 63;
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber ReadSector(ulong sectorAddress, out byte[] buffer)
{
buffer = null;
if(sectorAddress > _imageInfo.Sectors - 1)
return ErrorNumber.OutOfRange;
// Check cache
if(_sectorCache.TryGetValue(sectorAddress, out buffer))
return ErrorNumber.NoError;
ulong byteAddress = sectorAddress * 512;
ulong l1Off = (byteAddress & _l1Mask) >> _l1Shift;
if((long)l1Off >= _l1Table.LongLength)
{
AaruConsole.DebugWriteLine(MODULE_NAME,
string.Format(Localization.Trying_to_read_past_L1_table_position_0_of_a_max_1,
l1Off, _l1Table.LongLength));
return ErrorNumber.InvalidArgument;
}
// TODO: Implement differential images
if(_l1Table[l1Off] == 0)
{
buffer = new byte[512];
return ErrorNumber.NoError;
}
if(!_l2TableCache.TryGetValue(l1Off, out ulong[] l2Table))
{
_imageStream.Seek((long)_l1Table[l1Off], SeekOrigin.Begin);
byte[] l2TableB = new byte[_tableSize * 8];
_imageStream.EnsureRead(l2TableB, 0, (int)_tableSize * 8);
AaruConsole.DebugWriteLine(MODULE_NAME, Localization.Reading_L2_table_0, l1Off);
l2Table = MemoryMarshal.Cast<byte, ulong>(l2TableB).ToArray();
if(_l2TableCache.Count >= _maxL2TableCache)
_l2TableCache.Clear();
_l2TableCache.Add(l1Off, l2Table);
}
ulong l2Off = (byteAddress & _l2Mask) >> _clusterBits;
ulong offset = l2Table[l2Off];
buffer = new byte[512];
if(offset != 0 &&
offset != 1)
{
if(!_clusterCache.TryGetValue(offset, out byte[] cluster))
{
cluster = new byte[_qHdr.cluster_size];
_imageStream.Seek((long)offset, SeekOrigin.Begin);
_imageStream.EnsureRead(cluster, 0, (int)_qHdr.cluster_size);
if(_clusterCache.Count >= _maxClusterCache)
_clusterCache.Clear();
_clusterCache.Add(offset, cluster);
}
Array.Copy(cluster, (int)(byteAddress & _sectorMask), buffer, 0, 512);
}
if(_sectorCache.Count >= MAX_CACHED_SECTORS)
_sectorCache.Clear();
_sectorCache.Add(sectorAddress, buffer);
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber ReadSectors(ulong sectorAddress, uint length, out byte[] buffer)
{
buffer = null;
if(sectorAddress > _imageInfo.Sectors - 1)
return ErrorNumber.OutOfRange;
if(sectorAddress + length > _imageInfo.Sectors)
return ErrorNumber.OutOfRange;
var ms = new MemoryStream();
for(uint i = 0; i < length; i++)
{
ErrorNumber errno = ReadSector(sectorAddress + i, out byte[] sector);
if(errno != ErrorNumber.NoError)
return errno;
ms.Write(sector, 0, sector.Length);
}
buffer = ms.ToArray();
return ErrorNumber.NoError;
}
}
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