Files
Aaru/Aaru.Images/VMware/Read.cs

711 lines
28 KiB
C#

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename : Read.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
// Reads VMware 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 © 2011-2025 Natalia Portillo
// ****************************************************************************/
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;
using Aaru.CommonTypes;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;
using Aaru.Logging;
using Marshal = Aaru.Helpers.Marshal;
namespace Aaru.Images;
public sealed partial class VMware
{
#region IWritableImage Members
/// <inheritdoc />
public ErrorNumber Open(IFilter imageFilter)
{
Stream stream = imageFilter.GetDataForkStream();
_vmEHdr = new ExtentHeader();
_vmCHdr = new CowHeader();
bool embedded = false;
if(stream.Length > Marshal.SizeOf<ExtentHeader>())
{
stream.Seek(0, SeekOrigin.Begin);
byte[] vmEHdrB = new byte[Marshal.SizeOf<ExtentHeader>()];
stream.EnsureRead(vmEHdrB, 0, Marshal.SizeOf<ExtentHeader>());
_vmEHdr = Marshal.ByteArrayToStructureLittleEndian<ExtentHeader>(vmEHdrB);
}
if(stream.Length > Marshal.SizeOf<CowHeader>())
{
stream.Seek(0, SeekOrigin.Begin);
byte[] vmCHdrB = new byte[Marshal.SizeOf<CowHeader>()];
stream.EnsureRead(vmCHdrB, 0, Marshal.SizeOf<CowHeader>());
_vmCHdr = Marshal.ByteArrayToStructureLittleEndian<CowHeader>(vmCHdrB);
}
var ddfStream = new MemoryStream();
bool vmEHdrSet = false;
bool cowD = false;
if(_vmEHdr.magic == VMWARE_EXTENT_MAGIC)
{
vmEHdrSet = true;
_gdFilter = imageFilter;
if(_vmEHdr.descriptorOffset == 0 || _vmEHdr.descriptorSize == 0)
{
AaruLogging.Error(Localization.Please_open_VMDK_descriptor);
return ErrorNumber.InvalidArgument;
}
byte[] ddfEmbed = new byte[_vmEHdr.descriptorSize * SECTOR_SIZE];
stream.Seek((long)(_vmEHdr.descriptorOffset * SECTOR_SIZE), SeekOrigin.Begin);
stream.EnsureRead(ddfEmbed, 0, ddfEmbed.Length);
ddfStream.Write(ddfEmbed, 0, ddfEmbed.Length);
embedded = true;
}
else if(_vmCHdr.magic == VMWARE_COW_MAGIC)
{
_gdFilter = imageFilter;
cowD = true;
}
else
{
byte[] ddfMagic = new byte[0x15];
stream.Seek(0, SeekOrigin.Begin);
stream.EnsureRead(ddfMagic, 0, 0x15);
if(!_ddfMagicBytes.SequenceEqual(ddfMagic))
{
AaruLogging.Error(Localization.Not_a_descriptor);
return ErrorNumber.InvalidArgument;
}
stream.Seek(0, SeekOrigin.Begin);
byte[] ddfExternal = new byte[imageFilter.DataForkLength];
stream.EnsureRead(ddfExternal, 0, ddfExternal.Length);
ddfStream.Write(ddfExternal, 0, ddfExternal.Length);
}
_extents = new Dictionary<ulong, Extent>();
ulong currentSector = 0;
bool matchedCyls = false, matchedHds = false, matchedSpt = false;
if(cowD)
{
int cowCount = 1;
string basePath = Path.GetFileNameWithoutExtension(imageFilter.BasePath);
while(true)
{
string curPath;
if(cowCount == 1)
curPath = basePath + ".vmdk";
else
curPath = $"{basePath}-{cowCount:D2}.vmdk";
if(!File.Exists(curPath)) break;
IFilter extentFilter = PluginRegister.Singleton.GetFilter(curPath);
Stream extentStream = extentFilter.GetDataForkStream();
if(stream.Length > Marshal.SizeOf<CowHeader>())
{
extentStream.Seek(0, SeekOrigin.Begin);
byte[] vmCHdrB = new byte[Marshal.SizeOf<CowHeader>()];
extentStream.EnsureRead(vmCHdrB, 0, Marshal.SizeOf<CowHeader>());
CowHeader extHdrCow = Marshal.ByteArrayToStructureLittleEndian<CowHeader>(vmCHdrB);
if(extHdrCow.magic != VMWARE_COW_MAGIC) break;
var newExtent = new Extent
{
Access = "RW",
Filter = extentFilter,
Filename = extentFilter.Filename,
Offset = 0,
Sectors = extHdrCow.sectors,
Type = "SPARSE"
};
AaruLogging.Debug(MODULE_NAME,
"{0} {1} {2} \"{3}\" {4}",
newExtent.Access,
newExtent.Sectors,
newExtent.Type,
newExtent.Filename,
newExtent.Offset);
_extents.Add(currentSector, newExtent);
currentSector += newExtent.Sectors;
}
else
break;
cowCount++;
}
_imageType = VM_TYPE_SPLIT_SPARSE;
}
else
{
ddfStream.Seek(0, SeekOrigin.Begin);
var regexVersion = new Regex(REGEX_VERSION);
var regexCid = new Regex(REGEX_CID);
var regexParentCid = new Regex(REGEX_CID_PARENT);
var regexType = new Regex(REGEX_TYPE);
var regexExtent = new Regex(REGEX_EXTENT);
var regexParent = new Regex(PARENT_REGEX);
var regexCylinders = new Regex(REGEX_DDB_CYLINDERS);
var regexHeads = new Regex(REGEX_DDB_HEADS);
var regexSectors = new Regex(REGEX_DDB_SECTORS);
var ddfStreamRdr = new StreamReader(ddfStream);
while(ddfStreamRdr.Peek() >= 0)
{
string line = ddfStreamRdr.ReadLine();
Match matchVersion = regexVersion.Match(line);
Match matchCid = regexCid.Match(line);
Match matchParentCid = regexParentCid.Match(line);
Match matchType = regexType.Match(line);
Match matchExtent = regexExtent.Match(line);
Match matchParent = regexParent.Match(line);
Match matchCylinders = regexCylinders.Match(line);
Match matchHeads = regexHeads.Match(line);
Match matchSectors = regexSectors.Match(line);
if(matchVersion.Success)
{
uint.TryParse(matchVersion.Groups["version"].Value, out _version);
AaruLogging.Debug(MODULE_NAME, "version = {0}", _version);
}
else if(matchCid.Success)
{
_cid = Convert.ToUInt32(matchCid.Groups["cid"].Value, 16);
AaruLogging.Debug(MODULE_NAME, "cid = {0:x8}", _cid);
}
else if(matchParentCid.Success)
{
_parentCid = Convert.ToUInt32(matchParentCid.Groups["cid"].Value, 16);
AaruLogging.Debug(MODULE_NAME, "parentCID = {0:x8}", _parentCid);
}
else if(matchType.Success)
{
_imageType = matchType.Groups["type"].Value;
AaruLogging.Debug(MODULE_NAME, "createType = \"{0}\"", _imageType);
}
else if(matchExtent.Success)
{
var newExtent = new Extent
{
Access = matchExtent.Groups["access"].Value
};
if(!embedded)
{
newExtent.Filter =
PluginRegister.Singleton.GetFilter(Path.Combine(Path.GetDirectoryName(imageFilter.BasePath),
matchExtent.Groups["filename"].Value));
}
else
newExtent.Filter = imageFilter;
uint.TryParse(matchExtent.Groups["offset"].Value, out newExtent.Offset);
uint.TryParse(matchExtent.Groups["sectors"].Value, out newExtent.Sectors);
newExtent.Type = matchExtent.Groups["type"].Value;
AaruLogging.Debug(MODULE_NAME,
"{0} {1} {2} \"{3}\" {4}",
newExtent.Access,
newExtent.Sectors,
newExtent.Type,
newExtent.Filename,
newExtent.Offset);
_extents.Add(currentSector, newExtent);
currentSector += newExtent.Sectors;
}
else if(matchParent.Success)
{
_parentName = matchParent.Groups["filename"].Value;
AaruLogging.Debug(MODULE_NAME, "parentFileNameHint = \"{0}\"", _parentName);
_hasParent = true;
}
else if(matchCylinders.Success)
{
uint.TryParse(matchCylinders.Groups["cylinders"].Value, out _imageInfo.Cylinders);
matchedCyls = true;
}
else if(matchHeads.Success)
{
uint.TryParse(matchHeads.Groups["heads"].Value, out _imageInfo.Heads);
matchedHds = true;
}
else if(matchSectors.Success)
{
uint.TryParse(matchSectors.Groups["sectors"].Value, out _imageInfo.SectorsPerTrack);
matchedSpt = true;
}
}
}
if(_extents.Count == 0)
{
AaruLogging.Error(Localization.Did_not_find_any_extent);
return ErrorNumber.InvalidArgument;
}
switch(_imageType)
{
case VM_TYPE_MONO_SPARSE: //"monolithicSparse";
case VM_TYPE_MONO_FLAT: //"monolithicFlat";
case VM_TYPE_SPLIT_SPARSE: //"twoGbMaxExtentSparse";
case VM_TYPE_SPLIT_FLAT: //"twoGbMaxExtentFlat";
case VMFS_TYPE_FLAT: //"vmfsPreallocated";
case VMFS_TYPE_ZERO: //"vmfsEagerZeroedThick";
case VMFS_TYPE_THIN: //"vmfsThin";
case VMFS_TYPE_SPARSE: //"vmfsSparse";
case VMFS_TYPE: //"vmfs";
case VM_TYPE_STREAM: //"streamOptimized";
break;
case VM_TYPE_FULL_DEVICE: //"fullDevice";
case VM_TYPE_PART_DEVICE: //"partitionedDevice";
case VMFS_TYPE_RDM: //"vmfsRDM";
case VMFS_TYPE_RDM_OLD: //"vmfsRawDeviceMap";
case VMFS_TYPE_RDMP: //"vmfsRDMP";
case VMFS_TYPE_RDMP_OLD: //"vmfsPassthroughRawDeviceMap";
case VMFS_TYPE_RAW: //"vmfsRaw";
AaruLogging.Error(Localization.Raw_device_image_files_are_not_supported);
return ErrorNumber.NotSupported;
default:
AaruLogging.Error(string.Format(Localization.Dunno_how_to_handle_0_extents, _imageType));
return ErrorNumber.InvalidArgument;
}
bool oneNoFlat = cowD;
foreach(Extent extent in _extents.Values)
{
if(extent.Filter == null)
{
AaruLogging.Error(string.Format(Localization.Extent_file_0_not_found, extent.Filename));
return ErrorNumber.NoSuchFile;
}
if(extent.Access == "NOACCESS")
{
AaruLogging.Error(Localization.Cannot_access_NOACCESS_extents);
return ErrorNumber.InvalidArgument;
}
if(extent.Type is "FLAT" or "ZERO" or "VMFS" || cowD) continue;
Stream extentStream = extent.Filter.GetDataForkStream();
extentStream.Seek(0, SeekOrigin.Begin);
if(extentStream.Length < SECTOR_SIZE)
{
AaruLogging.Error(string.Format(Localization.Extent_0_is_too_small, extent.Filename));
return ErrorNumber.InvalidArgument;
}
byte[] extentHdrB = new byte[Marshal.SizeOf<ExtentHeader>()];
extentStream.EnsureRead(extentHdrB, 0, Marshal.SizeOf<ExtentHeader>());
ExtentHeader extentHdr = Marshal.ByteArrayToStructureLittleEndian<ExtentHeader>(extentHdrB);
if(extentHdr.magic != VMWARE_EXTENT_MAGIC)
{
AaruLogging.Error(string.Format(Localization._0_is_not_an_VMware_extent, extent.Filter));
return ErrorNumber.InvalidArgument;
}
if(extentHdr.capacity < extent.Sectors)
{
AaruLogging.Error(string.Format(Localization
.Extent_contains_incorrect_number_of_sectors_0_1_were_expected,
extentHdr.capacity,
extent.Sectors));
return ErrorNumber.InvalidArgument;
}
// TODO: Support compressed extents
if(extentHdr.compression != COMPRESSION_NONE)
{
AaruLogging.Error(Localization.Compressed_extents_are_not_yet_supported);
return ErrorNumber.NotImplemented;
}
if(!vmEHdrSet)
{
_vmEHdr = extentHdr;
_gdFilter = extent.Filter;
vmEHdrSet = true;
}
oneNoFlat = true;
}
if(oneNoFlat && !vmEHdrSet && !cowD)
{
AaruLogging.Error(Localization
.There_are_sparse_extents_but_there_is_no_header_to_find_the_grain_tables_cannot_proceed);
return ErrorNumber.InvalidArgument;
}
_imageInfo.Sectors = currentSector;
uint grains = 0;
uint gdEntries = 0;
long gdOffset = 0;
uint gtEsPerGt = 0;
switch(oneNoFlat)
{
case true when !cowD:
{
AaruLogging.Debug(MODULE_NAME, "vmEHdr.magic = 0x{0:X8}", _vmEHdr.magic);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.version = {0}", _vmEHdr.version);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.flags = 0x{0:X8}", _vmEHdr.flags);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.capacity = {0}", _vmEHdr.capacity);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.grainSize = {0}", _vmEHdr.grainSize);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.descriptorOffset = {0}", _vmEHdr.descriptorOffset);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.descriptorSize = {0}", _vmEHdr.descriptorSize);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.GTEsPerGT = {0}", _vmEHdr.GTEsPerGT);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.rgdOffset = {0}", _vmEHdr.rgdOffset);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.gdOffset = {0}", _vmEHdr.gdOffset);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.overhead = {0}", _vmEHdr.overhead);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.uncleanShutdown = {0}", _vmEHdr.uncleanShutdown);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.singleEndLineChar = 0x{0:X2}", _vmEHdr.singleEndLineChar);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.nonEndLineChar = 0x{0:X2}", _vmEHdr.nonEndLineChar);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.doubleEndLineChar1 = 0x{0:X2}", _vmEHdr.doubleEndLineChar1);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.doubleEndLineChar2 = 0x{0:X2}", _vmEHdr.doubleEndLineChar2);
AaruLogging.Debug(MODULE_NAME, "vmEHdr.compression = 0x{0:X4}", _vmEHdr.compression);
_grainSize = _vmEHdr.grainSize;
grains = (uint)(_imageInfo.Sectors / _vmEHdr.grainSize) + 1;
gdEntries = grains / _vmEHdr.GTEsPerGT;
gtEsPerGt = _vmEHdr.GTEsPerGT;
if((_vmEHdr.flags & FLAGS_USE_REDUNDANT_TABLE) == FLAGS_USE_REDUNDANT_TABLE)
gdOffset = (long)_vmEHdr.rgdOffset;
else
gdOffset = (long)_vmEHdr.gdOffset;
break;
}
case true when cowD:
AaruLogging.Debug(MODULE_NAME, "vmCHdr.magic = 0x{0:X8}", _vmCHdr.magic);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.version = {0}", _vmCHdr.version);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.flags = 0x{0:X8}", _vmCHdr.flags);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.sectors = {0}", _vmCHdr.sectors);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.grainSize = {0}", _vmCHdr.grainSize);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.gdOffset = {0}", _vmCHdr.gdOffset);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.numGDEntries = {0}", _vmCHdr.numGDEntries);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.freeSector = {0}", _vmCHdr.freeSector);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.cylinders = {0}", _vmCHdr.cylinders);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.heads = {0}", _vmCHdr.heads);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.spt = {0}", _vmCHdr.spt);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.generation = {0}", _vmCHdr.generation);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.name = {0}", StringHandlers.CToString(_vmCHdr.name));
AaruLogging.Debug(MODULE_NAME,
"vmCHdr.description = {0}",
StringHandlers.CToString(_vmCHdr.description));
AaruLogging.Debug(MODULE_NAME, "vmCHdr.savedGeneration = {0}", _vmCHdr.savedGeneration);
AaruLogging.Debug(MODULE_NAME, "vmCHdr.uncleanShutdown = {0}", _vmCHdr.uncleanShutdown);
_grainSize = _vmCHdr.grainSize;
grains = (uint)(_imageInfo.Sectors / _vmCHdr.grainSize) + 1;
gdEntries = _vmCHdr.numGDEntries;
gdOffset = _vmCHdr.gdOffset;
gtEsPerGt = grains / gdEntries;
_imageInfo.MediaTitle = StringHandlers.CToString(_vmCHdr.name);
_imageInfo.Comments = StringHandlers.CToString(_vmCHdr.description);
_version = _vmCHdr.version;
break;
}
if(oneNoFlat)
{
if(grains == 0 || gdEntries == 0)
{
AaruLogging.Error(Localization.Some_error_occurred_setting_GD_sizes);
return ErrorNumber.InOutError;
}
AaruLogging.Debug(MODULE_NAME,
Localization._0_sectors_in_1_grains_in_2_tables,
_imageInfo.Sectors,
grains,
gdEntries);
Stream gdStream = _gdFilter.GetDataForkStream();
gdStream.Seek(gdOffset * SECTOR_SIZE, SeekOrigin.Begin);
AaruLogging.Debug(MODULE_NAME, Localization.Reading_grain_directory);
byte[] gdBytes = new byte[gdEntries * 4];
gdStream.EnsureRead(gdBytes, 0, gdBytes.Length);
ReadOnlySpan<uint> gd = MemoryMarshal.Cast<byte, uint>(gdBytes);
AaruLogging.Debug(MODULE_NAME, Localization.Reading_grain_tables);
uint currentGrain = 0;
_gTable = new uint[grains];
foreach(uint gtOff in gd)
{
byte[] gtBytes = new byte[gtEsPerGt * 4];
gdStream.Seek(gtOff * SECTOR_SIZE, SeekOrigin.Begin);
gdStream.EnsureRead(gtBytes, 0, gtBytes.Length);
uint[] currentGt = MemoryMarshal.Cast<byte, uint>(gtBytes).ToArray();
Array.Copy(currentGt, 0, _gTable, currentGrain, gtEsPerGt);
currentGrain += gtEsPerGt;
// TODO: Check speed here
/*
for(int i = 0; i < gtEsPerGt; i++)
{
gTable[currentGrain] = BitConverter.ToUInt32(gtBytes, i * 4);
currentGrain++;
}
*/
}
_maxCachedGrains = (uint)(MAX_CACHE_SIZE / (_grainSize * SECTOR_SIZE));
_grainCache = new Dictionary<ulong, byte[]>();
}
if(_hasParent)
{
IFilter parentFilter =
PluginRegister.Singleton.GetFilter(Path.Combine(imageFilter.ParentFolder, _parentName));
if(parentFilter == null)
{
AaruLogging.Error(string.Format(Localization.Cannot_find_parent_0, _parentName));
return ErrorNumber.NoSuchFile;
}
_parentImage = new VMware();
ErrorNumber parentError = _parentImage.Open(parentFilter);
if(parentError != ErrorNumber.NoError)
{
AaruLogging.Error(string.Format(Localization.Error_0_opening_parent_1, parentError, _parentName));
return parentError;
}
}
_sectorCache = new Dictionary<ulong, byte[]>();
_imageInfo.CreationTime = imageFilter.CreationTime;
_imageInfo.LastModificationTime = imageFilter.LastWriteTime;
_imageInfo.MediaTitle = Path.GetFileNameWithoutExtension(imageFilter.Filename);
_imageInfo.SectorSize = SECTOR_SIZE;
_imageInfo.MetadataMediaType = MetadataMediaType.BlockMedia;
_imageInfo.MediaType = MediaType.GENERIC_HDD;
_imageInfo.ImageSize = _imageInfo.Sectors * SECTOR_SIZE;
// VMDK version 1 started on VMware 4, so there is a previous version, "COWD"
_imageInfo.Version = cowD ? $"{_version}" : $"{_version + 3}";
if(cowD)
{
_imageInfo.Cylinders = _vmCHdr.cylinders;
_imageInfo.Heads = _vmCHdr.heads;
_imageInfo.SectorsPerTrack = _vmCHdr.spt;
}
else if(!matchedCyls || !matchedHds || !matchedSpt)
{
_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;
if(_sectorCache.TryGetValue(sectorAddress, out buffer)) return ErrorNumber.NoError;
var currentExtent = new Extent();
bool extentFound = false;
ulong extentStartSector = 0;
foreach(KeyValuePair<ulong, Extent> kvp in _extents.Where(kvp => sectorAddress >= kvp.Key))
{
currentExtent = kvp.Value;
extentFound = true;
extentStartSector = kvp.Key;
}
if(!extentFound) return ErrorNumber.SectorNotFound;
Stream dataStream;
switch(currentExtent.Type)
{
case "ZERO":
buffer = new byte[SECTOR_SIZE];
if(_sectorCache.Count >= MAX_CACHED_SECTORS) _sectorCache.Clear();
_sectorCache.Add(sectorAddress, buffer);
return ErrorNumber.NoError;
case "FLAT":
case "VMFS":
dataStream = currentExtent.Filter.GetDataForkStream();
dataStream.Seek((long)((currentExtent.Offset + (sectorAddress - extentStartSector)) * SECTOR_SIZE),
SeekOrigin.Begin);
buffer = new byte[SECTOR_SIZE];
dataStream.EnsureRead(buffer, 0, buffer.Length);
if(_sectorCache.Count >= MAX_CACHED_SECTORS) _sectorCache.Clear();
_sectorCache.Add(sectorAddress, buffer);
return ErrorNumber.NoError;
}
ulong index = sectorAddress / _grainSize;
ulong secOff = sectorAddress % _grainSize * SECTOR_SIZE;
uint grainOff = _gTable[index];
switch(grainOff)
{
case 0 when _hasParent:
return _parentImage.ReadSector(sectorAddress, out buffer);
case 0 or 1:
{
buffer = new byte[SECTOR_SIZE];
if(_sectorCache.Count >= MAX_CACHED_SECTORS) _sectorCache.Clear();
_sectorCache.Add(sectorAddress, buffer);
return ErrorNumber.NoError;
}
}
if(!_grainCache.TryGetValue(grainOff, out byte[] grain))
{
grain = new byte[SECTOR_SIZE * _grainSize];
dataStream = currentExtent.Filter.GetDataForkStream();
dataStream.Seek((long)((grainOff - extentStartSector) * SECTOR_SIZE), SeekOrigin.Begin);
dataStream.EnsureRead(grain, 0, grain.Length);
if(_grainCache.Count >= _maxCachedGrains) _grainCache.Clear();
_grainCache.Add(grainOff, grain);
}
buffer = new byte[SECTOR_SIZE];
Array.Copy(grain, (int)secOff, buffer, 0, SECTOR_SIZE);
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;
}
#endregion
}