/// <summary>
/// Detects if a stream contains a valid ISO file system.
/// </summary>
/// <param name="data">The stream to inspect.</param>
/// <returns><c>true</c> if the stream contains an ISO file system, else false.</returns>
public static bool Detect(Stream data, int sectorSize)
{
byte[] buffer = new byte[sectorSize];
if (data.Length < 0x8000 + sectorSize)
{
return(false);
}
data.Position = 0x8000;
int numRead = StreamUtilities.ReadMaximum(data, buffer, 0, sectorSize);
if (numRead != sectorSize)
{
return(false);
}
BaseVolumeDescriptor bvd = new BaseVolumeDescriptor(buffer, 0);
return(bvd.StandardIdentifier == BaseVolumeDescriptor.Iso9660StandardIdentifier);
}
/// <summary>
/// Initializes a new instance of the VfsCDReader class.
/// </summary>
/// <param name="data">The stream to read the ISO image from.</param>
/// <param name="variantPriorities">Which possible file system variants to use, and with which priority.</param>
/// <param name="hideVersions">Hides version numbers (e.g. ";1") from the end of files.</param>
/// <remarks>
/// <para>
/// The implementation considers each of the file system variants in <c>variantProperties</c> and selects
/// the first which is determined to be present. In this example Joliet, then Rock Ridge, then vanilla
/// Iso9660 will be considered:
/// </para>
/// <code lang="cs">
/// VfsCDReader(stream, new Iso9660Variant[] {Joliet, RockRidge, Iso9660}, true);
/// </code>
/// <para>The Iso9660 variant should normally be specified as the final entry in the list. Placing it earlier
/// in the list will effectively mask later items and not including it may prevent some ISOs from being read.</para>
/// </remarks>
public VfsCDReader(Stream data, Iso9660Variant[] variantPriorities, bool hideVersions, int sectorSize)
: base(new DiscFileSystemOptions())
{
_data = data;
_sectorSize = sectorSize;
_hideVersions = hideVersions;
long vdpos = _sectorSize * 16; // Skip lead-in
byte[] buffer = new byte[_sectorSize];
long pvdPos = 0;
long svdPos = 0;
BaseVolumeDescriptor bvd;
do
{
data.Position = vdpos;
int numRead = data.Read(buffer, 0, _sectorSize);
if (numRead != _sectorSize)
{
break;
}
var offset = 24;
bvd = new BaseVolumeDescriptor(buffer, offset);
if (bvd.StandardIdentifier != BaseVolumeDescriptor.Iso9660StandardIdentifier)
{
throw new InvalidFileSystemException("Volume is not ISO-9660");
}
switch (bvd.VolumeDescriptorType)
{
case VolumeDescriptorType.Boot:
_bootVolDesc = new BootVolumeDescriptor(buffer, offset);
if (_bootVolDesc.SystemId != BootVolumeDescriptor.ElToritoSystemIdentifier)
{
_bootVolDesc = null;
}
break;
case VolumeDescriptorType.Primary: // Primary Vol Descriptor
pvdPos = vdpos;
break;
case VolumeDescriptorType.Supplementary: // Supplementary Vol Descriptor
svdPos = vdpos;
break;
case VolumeDescriptorType.Partition: // Volume Partition Descriptor
break;
case VolumeDescriptorType.SetTerminator: // Volume Descriptor Set Terminator
break;
}
vdpos += _sectorSize;
} while (bvd.VolumeDescriptorType != VolumeDescriptorType.SetTerminator);
ActiveVariant = Iso9660Variant.None;
foreach (Iso9660Variant variant in variantPriorities)
{
switch (variant)
{
case Iso9660Variant.Joliet:
if (svdPos != 0)
{
data.Position = svdPos;
data.Read(buffer, 0, _sectorSize);
SupplementaryVolumeDescriptor volDesc = new SupplementaryVolumeDescriptor(buffer, 0);
Context = new IsoContext(_sectorSize)
{
VolumeDescriptor = volDesc, DataStream = _data
};
RootDirectory = new ReaderDirectory(Context,
new ReaderDirEntry(Context, volDesc.RootDirectory));
ActiveVariant = Iso9660Variant.Iso9660;
}
break;
case Iso9660Variant.RockRidge:
case Iso9660Variant.Iso9660:
if (pvdPos != 0)
{
data.Position = pvdPos + 24;
data.Read(buffer, 0, _sectorSize);
PrimaryVolumeDescriptor volDesc = new PrimaryVolumeDescriptor(buffer, 0);
volDesc.LogicalBlockSize = 2352;
IsoContext context = new IsoContext(_sectorSize)
{
VolumeDescriptor = volDesc, DataStream = _data
};
DirectoryRecord rootSelfRecord = ReadRootSelfRecord(context);
InitializeSusp(context, rootSelfRecord);
if (variant == Iso9660Variant.Iso9660
||
(variant == Iso9660Variant.RockRidge &&
!string.IsNullOrEmpty(context.RockRidgeIdentifier)))
{
Context = context;
RootDirectory = new ReaderDirectory(context, new ReaderDirEntry(context, rootSelfRecord));
ActiveVariant = variant;
}
}
break;
}
if (ActiveVariant != Iso9660Variant.None)
{
break;
}
}
if (ActiveVariant == Iso9660Variant.None)
{
throw new IOException("None of the permitted ISO9660 file system variants was detected");
}
}
