private void GetDataIdentifiersRecursiveUsingIndex(IEnumerable<byte> bytesSoFar, int depth, Int64 offset, ICollection<Guid> result, StreamStateBehaviour indexStreamStateBehaviour, ExposeProgressDelegate anotherDataIdentifierFoundDelegate)
{
AllocationTableStruct indexStructs = GetIndexStruct(offset, indexStreamStateBehaviour);
for (int currentByteValue = 0; currentByteValue <= 255; currentByteValue++)
{
if (indexStructs.Pointers[currentByteValue] == 0)
{
// not used, recursion stops
}
else
{
//
// clone bytes so far, extend with current byte
//
var bytesForGuid = new List<byte>();
bytesForGuid.AddRange(bytesSoFar);
bytesForGuid.Add((byte) currentByteValue);
if (depth == 15)
{
var newGuid = new Guid(bytesForGuid.ToArray());
result.Add(newGuid);
//
// notify outside world we found another hit, if the outside world wants to hear about it
//
if (anotherDataIdentifierFoundDelegate != null)
{
anotherDataIdentifierFoundDelegate.Invoke(newGuid);
}
//
// recursion stops; this is the last byte
//
}
else
{
//
// continue recursion
//
long newOffset = indexStructs.Pointers[currentByteValue];
GetDataIdentifiersRecursiveUsingIndex(bytesForGuid, depth + 1, newOffset, result, indexStreamStateBehaviour, anotherDataIdentifierFoundDelegate);
}
}
}
}
public void RestoreIndexFile(AddFileBehaviour addFileBehaviour, StreamStateBehaviour indexStreamStateBehaviour, StreamStateBehaviour dataStreamStateBehaviour, ExposeProgressDelegate exposeProgressDelegate)
{
//
// the following method also checks whether the index file exists or not,
// if exists, it throws an exception
//
CreateNewFileStorage_IndexFile(IndexFilename);
switch (indexStreamStateBehaviour)
{
case StreamStateBehaviour.OpenNewStreamForReadingAndWriting:
// ok
break;
default:
throw new NotSupportedException(string.Format("Unexpected indexStreamStateBehaviour {0}", indexStreamStateBehaviour));
}
switch (dataStreamStateBehaviour)
{
case StreamStateBehaviour.OpenNewStreamForReading:
// ok
break;
default:
throw new NotSupportedException(string.Format("Unexpected dataStreamStateBehaviour {0}", dataStreamStateBehaviour));
}
using (IndexStream = FileStreamFactory.CreateFileStream(IndexFilename, StreamStateBehaviour.OpenNewStreamForReadingAndWriting))
{
using (DataStream = FileStreamFactory.CreateFileStream(DataFilename, StreamStateBehaviour.OpenNewStreamForReading))
{
long dataSize = DataStream.Length;
long offset = OffsetFirstDataBlock;
while (true)
{
InterpretedDataFileDataStruct retrieveFileStruct = GetInterpretedDataStructUsingExistingStream(offset);
//
// the offset in the index file should point to the starting location
// of the data struct, this is not the offset where the actual data of
// the file is stored, but the start of the struct before the actual data.
//
Guid dataIdentifier = retrieveFileStruct.DataIdentification;
//
// if the data file contains duplicate dataIdentifiers, we will override previous ones (which
// is acceptable, as new files are appeneded to the data file, so more up to date files are stored
// after older ones).
//
BuildIndex(dataIdentifier, offset, BuildIndexBehaviour.OverrideWhenAlreadyExists, StreamStateBehaviour.UseExistingStream);
//
// jump to the next data block
//
offset = retrieveFileStruct.BinaryDataOffset + retrieveFileStruct.BinaryDataSizeInBytes;
//
// inform the outside world about the progress we've made,
// in case the outside world is interested
//
if (exposeProgressDelegate != null)
{
exposeProgressDelegate.Invoke(dataIdentifier);
}
if (offset >= dataSize)
{
//
// reach the end of the file
//
break;
}
}
}
}
if (exposeProgressDelegate != null)
{
exposeProgressDelegate.Invoke(true);
}
}
public List<Guid> GetAllDataIdentifiersBasedUponFileStorageIndexFile(StreamStateBehaviour indexStreamStateBehaviour, ExposeProgressDelegate exposeProgressDelegate)
{
List<Guid> result;
switch (indexStreamStateBehaviour)
{
case StreamStateBehaviour.UseExistingStream:
result = new List<Guid>();
long offset = OffsetFirstIndexBlock;
var bytes = new List<byte>();
int depth = 0;
GetDataIdentifiersRecursiveUsingIndex(bytes, depth, offset, result, indexStreamStateBehaviour, exposeProgressDelegate);
break;
case StreamStateBehaviour.OpenNewStreamForReading:
//
// open the index stream for reading and make a recursive call
//
using (IndexStream = new FileStream(IndexFilename, FileMode.Open, FileAccess.Read))
{
result = GetAllDataIdentifiersBasedUponFileStorageIndexFile(StreamStateBehaviour.UseExistingStream, exposeProgressDelegate);
}
break;
default:
throw new NotSupportedException(string.Format("indexStreamStateBehaviour {0} is not supported", indexStreamStateBehaviour));
}
if (exposeProgressDelegate != null)
{
exposeProgressDelegate.Invoke(true);
}
return result;
}