private static ulong GetCompressedLength(IEnumerable <byte[]> fileChunks)
{
ulong result = 0;
try
{
using (MemoryStream outStream = new MemoryStream())
{
using (GZipStream gzip = new GZipStream(outStream, CompressionMode.Compress))
{
using (MemoryStream inStream = new MemoryStream(Int16.MaxValue))
{
foreach (byte[] chunk in fileChunks)
{
inStream.Write(chunk, 0, chunk.Length);
}
Task copyTask = inStream.CopyToAsync(gzip, chunkSize, CancellationHelper.GetCancellationToken());
copyTask.Wait(CancellationHelper.GetCancellationToken());
result = (ulong)outStream.Length;
}
}
}
}
catch
{ }
return(result);
}
public static double?CalculateFileEntropy(byte[] fileBytes)
{
double?result = null;
CancellationHelper.ThrowIfCancelled();
ulong uncompressedLength = (ulong)fileBytes.LongLength;
if (uncompressedLength > 20)
{
ulong compressedLength = GetCompressedLength(fileBytes);
if (compressedLength > 0)
{
CancellationHelper.ThrowIfCancelled();
result = CalculateRatio(uncompressedLength, compressedLength);
}
}
return(result);
}
public static double?CalculateFileEntropy(IEnumerable <byte[]> fileChunks, ulong fileSize)
{
double?result = null;
CancellationHelper.ThrowIfCancelled();
ulong uncompressedLength = fileSize;
if (uncompressedLength > 20)
{
ulong compressedLength = GetCompressedLength(fileChunks);
if (compressedLength > 0)
{
CancellationHelper.ThrowIfCancelled();
result = CalculateRatio(uncompressedLength, compressedLength);
}
}
return(result);
}
private static string GetHashFromByteStream <HASHER>(Stream fileStream) where HASHER : HashAlgorithm, new()
{
string result = string.Empty;
try
{
using (HASHER hashAlgorithm = new HASHER())
{
long bytesToHash = fileStream.Length;
byte[] buffer = new byte[bigChunkSize];
int sizeToRead = buffer.Length;
while (bytesToHash > 0)
{
if (bytesToHash < (long)sizeToRead)
{
sizeToRead = (int)bytesToHash;
}
int bytesRead = fileStream.ReadAsync(buffer, 0, sizeToRead, CancellationHelper.GetCancellationToken()).Result;
CancellationHelper.ThrowIfCancelled();
hashAlgorithm.TransformBlock(buffer, 0, bytesRead, null, 0);
bytesToHash -= (long)bytesRead;
if (bytesRead == 0)
{
throw new InvalidOperationException("Unexpected end of stream"); // or break;
}
}
hashAlgorithm.TransformFinalBlock(buffer, 0, 0);
buffer = null;
result = ByteArrayConverter.ToHexString(hashAlgorithm.Hash);
}
}
catch { }
return(result);
}
private static ulong GetCompressedLength(byte[] fileBytes)
{
ulong result = 0;
try
{
using (MemoryStream outStream = new MemoryStream())
{
using (GZipStream gzip = new GZipStream(outStream, CompressionMode.Compress))
{
using (MemoryStream inStream = new MemoryStream(fileBytes))
{
Task copyTask = inStream.CopyToAsync(gzip, chunkSize, CancellationHelper.GetCancellationToken());
copyTask.Wait(CancellationHelper.GetCancellationToken());
result = (ulong)outStream.Length;
}
}
}
}
catch
{ }
return(result);
}
