Develop Reference

C# BinaryWriter, Write with 8 bit

Im Using Binarywriter to save blob data (PDF) from oracle to disk.
The result is ugly when i open the generated file. I think its the problem of that 1 character is write with one byte.
How can i increase to write to 8. (/BitsPerComponent 8)
Any Ideas ?
long CurrentIndex = 0;
int BufferSize = 10000;
long BytesReturned;
byte[] Blob = new byte[BufferSize];
OracleDataReader reader = comando.ExecuteReader(CommandBehavior.SequentialAccess);
string filepath = "C:\\ttttt.pdf";
while (reader.Read())
{
FileStream fs = new FileStream(filepath, FileMode.OpenOrCreate, FileAccess.Write);
BinaryWriter writer = new BinaryWriter(fs);
//reset the index to the beginning of the file
CurrentIndex = 0;
BytesReturned = reader.GetBytes(0, CurrentIndex, Blob, 0, BufferSize);
while (BytesReturned == BufferSize)
{
writer.Write(Blob);
writer.Flush();
CurrentIndex += BufferSize;
BytesReturned = reader.GetBytes(0, CurrentIndex, Blob, 0, BufferSize);
}
writer.Write(Blob, 0, (int)BytesReturned);
writer.Flush();
writer.Close();
fs.Close();
}

You don't need a BinaryWriter for this. Just write to the stream directly. BinaryWriter's intended use case is writing primitive data types to a stream for serialization purposes.
Update: Automatically generate a filename from Base64(MD5(Blob)).
long CurrentIndex = 0;
int BufferSize = 10000;
long BytesReturned;
byte[] Blob = new byte[BufferSize];
using (var hasher = MD5.Create())
{
using (var reader = comando.ExecuteReader(CommandBehavior.SequentialAccess))
{
while (reader.Read())
{
var filename = Convert.ToBase64String(hasher.ComputeHash(Blob)).Replace("=", string.Empty);
var filepath = Path.ChangeExtension(Path.Combine("C:\\", filename), ".pdf");
using (var fs = new FileStream(filepath, FileMode.OpenOrCreate, FileAccess.Write))
{
//reset the index to the beginning of the file
CurrentIndex = 0;
BytesReturned = reader.GetBytes(0, CurrentIndex, Blob, 0, BufferSize);
while (BytesReturned == BufferSize)
{
fs.Write(Blob, 0, Blob.Length);
CurrentIndex += BufferSize;
BytesReturned = reader.GetBytes(0, CurrentIndex, Blob, 0, BufferSize);
}
fs.Write(Blob, 0, (int)BytesReturned);
}
}
}
}

GZipStream sum compressing blocks to file

I make an archiver with block-by-block reading and file compression. I put the compressed block in FileStream.
I am reading the 5 mb block. The problem is that if I compress a pic of 8 mb, then when I pull it out of the resulting archive, its sum-hash does not match the original and it opens pic halfway, and the size is the same... I don’t know what to try. I ask for help.
Read chunk void:
private byte[] ReadChunk(int chunkId)
{
using (var inFile = new FileStream(sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read))
{
long filePosition = chunkId * chunkDataSize;
int bytesRead;
if (inFile.Length - filePosition <= chunkDataSize)
{
bytesRead = (int)(inFile.Length - filePosition);
}
else
{
bytesRead = chunkDataSize;
}
var lastBuffer = new byte[bytesRead];
inFile.Read(lastBuffer, 0, bytesRead);
return lastBuffer;
}
}
Compress and write void:
private void CompressBlock(byte[] bytesTo)
{
using (MemoryStream ms = new MemoryStream())
{
using (GZipStream gs = new GZipStream(ms, CompressionMode.Compress))
{
gs.Write(bytesTo, 0, bytesTo.Length);
}
byte[] compressedData = ms.ToArray();
using (var outFile = new FileStream(resultFile, FileMode.Append))
{
BitConverter.GetBytes(compressedData.Length).CopyTo(compressedData, 4);
outFile.Write(compressedData, 0, compressedData.Length);
}
}
}

Async download file in c#

I need help to improve this code but I do not understand where I made a mistake. The file is downloaded but in a corrupted format. I am using cookies also which is a required part of this method.
/*Downlod task */
public static async Task<int> CreateDownloadTask(string urlToDownload,string sDestinationPath, string cookiedstr)
{
int BufferSize = 4096;
int receivedBytes = 0;
int totalBytes = 0;
WebClient client = new WebClient();
client.Headers.Add(HttpRequestHeader.Cookie, cookiedstr);
using (var stream = await client.OpenReadTaskAsync(urlToDownload))
{
using (MemoryStream ms = new MemoryStream())
{
int read = 0;
totalBytes = Int32.Parse(client.ResponseHeaders[HttpResponseHeader.ContentLength]);
var buffer = new byte[BufferSize];
while ((read = await stream.ReadAsync(buffer, 0, buffer.Length)) > 0)
{
ms.Write(buffer, 0, read);
FileStream file = new FileStream(sDestinationPath, FileMode.Append, FileAccess.Write);
ms.Position = 0;
ms.WriteTo(file);
file.Flush();
file.Close();
buffer = new byte[BufferSize];
receivedBytes += read;
Console.WriteLine(receivedBytes + " " + totalBytes);
// DownloadBytesProgress args = new DownloadBytesProgress(urlToDownload, receivedBytes, totalBytes);
}
ms.Close();
}
return receivedBytes;
}
}

Silverlight becomes unresponsive when downloading a file

I'm trying to use the following snippet in order download files via the SaveFileDialog in Silverlight:
public void SaveMediaLocal(string fileName)
{
FileInfo fInfo = new FileInfo(fileName);
if (fInfo.Exists)
{
if (fInfo.Length > 0)
{
string extension = fInfo.Extension;
SaveFileDialog dialog = new SaveFileDialog()
{
DefaultExt = extension,
Filter = String.Format("{1} files (*.{0})|*.{0}|All files (*.*)|*.*", extension, fInfo.Extension),
FilterIndex = 1,
DefaultFileName = fInfo.Name
};
if (dialog.ShowDialog() == true)
{
try
{
bool cancelFlag = false;
byte[] buffer = new byte[1024 * 1024]; // 1GB buffer
using (FileStream dest = (FileStream)dialog.OpenFile())
{
using (FileStream source = new FileStream(fInfo.FullName, FileMode.Open, FileAccess.Read))
{
long fileLength = source.Length;
long totalBytes = 0;
int currentBlockSize = 0;
while ((currentBlockSize = source.Read(buffer, 0, buffer.Length)) > 0)
{
totalBytes += currentBlockSize;
double percentage = (double)totalBytes * 100.0 / fileLength;
dest.Write(buffer, 0, currentBlockSize);
}
}
}
}
catch
{
}
}
}
else
{
//no results
}
}
}
When I use this snippet; Silverlight freezes until the download completes.
When I use this snippet instead, the UI is responsive, but doesn't work on bigger files.
using (Stream stream = dialog.OpenFile())
{
Byte[] bytes = File.ReadAllBytes(fileName);
stream.Write(bytes, 0, bytes.Length);
}
Is there something that I'm missing here?

Don't do the operation on the GUI thread. That is why it gets unresponsive. Either create a new thread or async process and do the operation in the background.

decompress a .gz file using GZipStream

I have several .gz files, and I want to decompress them one by one.
I have writen a simple code using GzipStream in C#, but got failed. I wonder a correct and useful method to achieve what I want. Thanks a lot.
private string Extrgz(string infile)
{
string dir = Path.GetDirectoryName(infile);
string decompressionFileName = dir + Path.GetFileNameWithoutExtension(infile) + "_decompression.bin";
using (GZipStream instream = new GZipStream(File.OpenRead(infile), CompressionMode.Compress))// ArgumentException...
{
using (FileStream outputStream = new FileStream(decompressionFileName, FileMode.Append, FileAccess.Write))
{
int bufferSize = 8192, bytesRead = 0;
byte[] buffer = new byte[bufferSize];
while ((bytesRead = instream.Read(buffer, 0, bufferSize)) > 0)
{
outputStream.Write(buffer, 0, bytesRead);
}
}
}
return decompressionFileName;
}

You need to decompress but you set CompressionMode.Compress, replace it with CompressionMode.Decompress.
Example here.

Here:
public static void DeCompressFile(string CompressedFile, string DeCompressedFile)
{
byte[] buffer = new byte[1024 * 1024];
using (System.IO.FileStream fstrmCompressedFile = System.IO.File.OpenRead(CompressedFile)) // fi.OpenRead())
{
using (System.IO.FileStream fstrmDecompressedFile = System.IO.File.Create(DeCompressedFile))
{
using (System.IO.Compression.GZipStream strmUncompress = new System.IO.Compression.GZipStream(fstrmCompressedFile,
System.IO.Compression.CompressionMode.Decompress))
{
int numRead = strmUncompress.Read(buffer, 0, buffer.Length);
while (numRead != 0)
{
fstrmDecompressedFile.Write(buffer, 0, numRead);
fstrmDecompressedFile.Flush();
numRead = strmUncompress.Read(buffer, 0, buffer.Length);
} // Whend
//int numRead = 0;
//while ((numRead = strmUncompress.Read(buffer, 0, buffer.Length)) != 0)
//{
// fstrmDecompressedFile.Write(buffer, 0, numRead);
// fstrmDecompressedFile.Flush();
//} // Whend
strmUncompress.Close();
} // End Using System.IO.Compression.GZipStream strmUncompress
fstrmDecompressedFile.Flush();
fstrmDecompressedFile.Close();
} // End Using System.IO.FileStream fstrmCompressedFile
fstrmCompressedFile.Close();
} // End Using System.IO.FileStream fstrmCompressedFile
} // End Sub DeCompressFile
// http://www.dotnetperls.com/decompress
public static byte[] Decompress(byte[] gzip)
{
byte[] baRetVal = null;
using (System.IO.MemoryStream ByteStream = new System.IO.MemoryStream(gzip))
{
// Create a GZIP stream with decompression mode.
// ... Then create a buffer and write into while reading from the GZIP stream.
using (System.IO.Compression.GZipStream stream = new System.IO.Compression.GZipStream(ByteStream
, System.IO.Compression.CompressionMode.Decompress))
{
const int size = 4096;
byte[] buffer = new byte[size];
using (System.IO.MemoryStream memory = new System.IO.MemoryStream())
{
int count = 0;
count = stream.Read(buffer, 0, size);
while (count > 0)
{
memory.Write(buffer, 0, count);
memory.Flush();
count = stream.Read(buffer, 0, size);
}
baRetVal = memory.ToArray();
memory.Close();
}
stream.Close();
} // End Using System.IO.Compression.GZipStream stream
ByteStream.Close();
} // End Using System.IO.MemoryStream ByteStream
return baRetVal;
} // End Sub Decompress