public static PartitionMap CreateFrom(byte[] buffer, int offset)
{
PartitionMap result = null;
byte type = buffer[offset];
if (type == 1)
{
result = new Type1PartitionMap();
}
else if (type == 2)
{
EntityIdentifier id = Utilities.ToStruct<UdfEntityIdentifier>(buffer, offset + 4);
switch (id.Identifier)
{
case "*UDF Virtual Partition":
result = new VirtualPartitionMap();
break;
case "*UDF Sparable Partition":
result = new SparablePartitionMap();
break;
case "*UDF Metadata Partition":
result = new MetadataPartitionMap();
break;
default:
throw new InvalidDataException("Unrecognized partition map entity id: " + id);
}
}
if (result != null)
{
result.ReadFrom(buffer, offset);
}
return result;
}
public MetadataPartition(UdfContext context, LogicalVolumeDescriptor volumeDescriptor, MetadataPartitionMap partitionMap)
: base(context, volumeDescriptor)
{
_partitionMap = partitionMap;
PhysicalPartition physical = context.PhysicalPartitions[partitionMap.PartitionNumber];
long fileEntryPos = partitionMap.MetadataFileLocation * (long)volumeDescriptor.LogicalBlockSize;
byte[] entryData = Utilities.ReadFully(physical.Content, fileEntryPos, _context.PhysicalSectorSize);
if (!DescriptorTag.IsValid(entryData, 0))
{
throw new IOException("Invalid descriptor tag looking for Metadata file entry");
}
DescriptorTag dt = Utilities.ToStruct<DescriptorTag>(entryData, 0);
if (dt.TagIdentifier == TagIdentifier.ExtendedFileEntry)
{
ExtendedFileEntry efe = Utilities.ToStruct<ExtendedFileEntry>(entryData, 0);
_metadataFile = new File(context, physical, efe, _volumeDescriptor.LogicalBlockSize);
}
else
{
throw new NotImplementedException("Only EFE implemented for Metadata file entry");
}
}
