public IList<RdcNeed> CreateNeedsList(SignatureInfo seedSignature, SignatureInfo sourceSignature,
CancellationToken token)
{
var result = new List<RdcNeed>();
using (var seedStream = _seedSignatureRepository.GetContentForReading(seedSignature.Name))
using (var sourceStream = _sourceSignatureRepository.GetContentForReading(sourceSignature.Name))
{
var fileReader = (IRdcFileReader)new RdcFileReader(seedStream);
IRdcComparator comparator;
if (_rdcLibrary.CreateComparator(fileReader, ComparatorBufferSize, out comparator) != 0)
throw new RdcException("Cannot create comparator");
var inputBuffer = new RdcBufferPointer
{
Size = 0,
Used = 0,
Data = Marshal.AllocCoTaskMem(InputBufferSize + 16)
};
var outputBuffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(RdcNeed)) * 256);
try
{
var eofInput = false;
var eofOutput = false;
var outputPointer = new RdcNeedPointer();
while (!eofOutput)
{
token.ThrowIfCancellationRequested();
if (inputBuffer.Size == inputBuffer.Used && !eofInput)
{
var bytesRead = 0;
try
{
bytesRead = RdcBufferTools.IntPtrCopy(sourceStream, inputBuffer.Data, InputBufferSize);
}
catch (Exception ex)
{
throw new RdcException("Failed to read from the source stream.", ex);
}
inputBuffer.Size = (uint)bytesRead;
inputBuffer.Used = 0;
if (bytesRead < InputBufferSize)
{
eofInput = true;
}
}
// Initialize our output needs array
outputPointer.Size = 256;
outputPointer.Used = 0;
outputPointer.Data = outputBuffer;
RdcError error;
var hr = comparator.Process(eofInput, ref eofOutput, ref inputBuffer, ref outputPointer, out error);
if (hr != 0)
throw new RdcException("Failed to process the signature block!", hr, error);
// Convert the stream to a Needs array.
var needs = GetRdcNeedList(outputPointer);
result.AddRange(needs);
}
}
finally
{
// Free our resources
if (outputBuffer != IntPtr.Zero)
Marshal.FreeCoTaskMem(outputBuffer);
if (inputBuffer.Data != IntPtr.Zero)
Marshal.FreeCoTaskMem(inputBuffer.Data);
}
return result;
}
}
private static RdcNeed[] GetRdcNeedList(RdcNeedPointer pointer)
{
var result = new RdcNeed[pointer.Used];
var ptr = pointer.Data;
var needSize = Marshal.SizeOf(typeof(RdcNeed));
// Get our native needs pointer
// and deserialize to our managed
// RdcNeed array.
for (var i = 0; i < result.Length; i++)
{
result[i] = (RdcNeed)Marshal.PtrToStructure(ptr, typeof(RdcNeed));
// Advance the intermediate pointer
// to our next RdcNeed struct.
ptr = new IntPtr(ptr.ToInt64() + needSize);
}
return result;
}