I've been trying to convert a GZipStream into a MemoryStream and then convert it to a byte array without having to write any files to the hard drive. I've been trying to copy it to a MemoryStream but I've been getting this error: Unhandled Exception: System.ObjectDisposedException: Cannot access a closed Stream.
I've looked at some of the other solutions, but I haven't been able to successfully implement them into what I'm trying to accomplish.
GZipStream decompressedStream = Decompress(new FileInfo(args[0]));
using (var finalStream = new MemoryStream())
{
decompressedStream.CopyTo(finalStream);
byte[] decompressedBytes = new byte[finalStream.Length];
}
EDIT: Somebody wanted me to add the code for Decompress() so here it is
public static GZipStream Decompress(FileInfo fileToDecompress)
{
using (FileStream originalFileStream = fileToDecompress.OpenRead())
{
string currentFileName = fileToDecompress.FullName;
string newFileName = currentFileName.Remove(currentFileName.Length - fileToDecompress.Extension.Length) + " (decompressed)";
using (FileStream decompressedFileStream = File.Create(newFileName))
{
using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
{
return decompressionStream;
}
}
}
}
The issue is here:
using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
{
return decompressionStream;
}
using statement (see this article) disposes the stream and you can't use it outside of the block. Move your MemoryStream handling inside this block and return byte[] from the method.
Something like this should work:
public static byte[] Decompress(FileInfo fileToDecompress)
{
using (FileStream originalFileStream = fileToDecompress.OpenRead())
{
string currentFileName = fileToDecompress.FullName;
string newFileName = currentFileName.Remove(currentFileName.Length - fileToDecompress.Extension.Length) + " (decompressed)";
using (FileStream decompressedFileStream = File.Create(newFileName))
{
using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
using (var finalStream = new MemoryStream())
{
decompressionStream.CopyTo(finalStream);
return finalStream.ToArray();
}
}
}
}
Related
I am working on an existing system where data is stored in a compressed byte array in a database.
The existing data has all been compressed using GZipDotNet.dll.
I am trying to switch to using the gzip functions in System.IO.Compression.
When I use:
public static byte[] DeCompressByteArray(byte[] inArray)
{
byte[] outStream = null;
outStream = GZipDotNet.GZip.Uncompress(inArray);
return outStream;
}
It works fine but:
public static byte[] DeCompressByteArray(byte[] inArray)
{
byte[] outStream = null;
using (var compressedStream = new MemoryStream(inArray))
using (var zipStream = new GZipStream(compressedStream, CompressionMode.Decompress))
using (var resultStream = new MemoryStream())
{
zipStream.CopyTo(resultStream);
outStream = resultStream.ToArray();
}
return outStream;
}
Gives a response of:
The magic number in GZip header is not correct. Make sure you are passing in a GZip stream
I use GZipSream to compress and decompress text file. But there is no whitespaces in decompressed file.
My code for compress:
using (FileStream sourceStream = new FileStream(sourceFile, FileMode.OpenOrCreate))
{
using (FileStream targetStream = File.Create(compressedFile))
{
using (GZipStream compressionStream = new GZipStream(targetStream, CompressionMode.Compress))
{
sourceStream.CopyTo(compressionStream);
}
}
}
For decompress:
using (FileStream sourceStream = new FileStream(compressedFile, FileMode.OpenOrCreate))
{
using (FileStream targetStream = File.Create(targetFile))
{
using (GZipStream decompressionStream = new GZipStream(sourceStream, CompressionMode.Decompress))
{
decompressionStream.CopyTo(targetStream);
}
}
}
Example uncompressed input:
2018-11-13 00:02:40,574 76 INFO
Decompressed:
2018-11-1300:02:40,57476INFO
This code will compress and serialize the object:
public static byte[] ObjectToByteArray(object[] obj)
{
using (MemoryStream msCompressed = new MemoryStream())
using (GZipStream gZipStream = new GZipStream(msCompressed, CompressionMode.Compress))
using (MemoryStream msDecompressed = new MemoryStream())
{
new BinaryFormatter().Serialize(msDecompressed, obj);
byte[] byteArray = msDecompressed.ToArray();
gZipStream.Write(byteArray, 0, byteArray.Length);
gZipStream.Close();
return msCompressed.ToArray();
}
}
And the following will upload it to the Azure Blob Storage:
byte[] byteObject = ObjectToByteArray(uploadObject);
using (Stream stream = new MemoryStream(byteObject))
{
stream.Seek(0, SeekOrigin.Begin);
blockBlob.UploadFromStream(stream, null, options);
}
This works great, but I can't find a way to download, decompress and deserialize this object/file from my storage.
You could use method DownloadToStream to download the file to local.
using (var fileStream = System.IO.File.OpenWrite(#"xxxx\compressedfile.gz"))
{
blockBlob.DownloadToStream(fileStream);
}
And then you could refer to the following code to decompress and deserialize the specified stream.
public static void DecompressAndDeserialize(string path)
{
using (FileStream originalFileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
{
FileInfo fileToDecompress = new FileInfo(path);
string FileName = fileToDecompress.FullName;
string newFileName = FileName.Remove(FileName.Length - fileToDecompress.Extension.Length);
using (FileStream decompressedFileStream = File.Create(newFileName))
{
using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
{
decompressionStream.CopyTo(decompressedFileStream);
}
}
FileStream fs = new FileStream(newFileName, FileMode.Open);
BinaryFormatter formatter = new BinaryFormatter();
object[] uploadObject = (object[])formatter.Deserialize(fs);
}
}
I am working in win forms. Getting errors while doing following operation.
It shows me System.OutOfMemoryException error when i try to run the operation around 2-3 times continuously. Seems .NET is not able to free the resouces used in operation. The file i am using for operation is quite big, around more than 500 MB.
My sample code is as below. Please help me how to resolve the error.
try
{
using (FileStream target = new FileStream(strCompressedFileName, FileMode.Create, FileAccess.Write))
using (GZipStream alg = new GZipStream(target, CompressionMode.Compress))
{
byte[] data = File.ReadAllBytes(strFileToBeCompressed);
alg.Write(data, 0, data.Length);
alg.Flush();
data = null;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
Replace ReadAllBytes with Stream.CopyTo
using (FileStream target = new FileStream(strCompressedFileName, FileMode.Create, FileAccess.Write))
using (GZipStream alg = new GZipStream(target, CompressionMode.Compress))
{
using (var fileToRead = File.Open(.....))
{
fileToRead.CopyTo(alg);
}
}
A very rough example could be
// destFile - FileStream for destinationFile
// srcFile - FileStream of sourceFile
using (GZipStream gz = new GZipStream(destFile, CompressionMode.Compress))
{
byte[] src = new byte[1024];
int count = sourceFile.Read(src, 0, 1024);
while (count != 0)
{
gz.Write(src, 0, count );
count = sourceFile.Read(src, 0, 1024);
}
}
// flush, close, dispose ..
So basically I changed your ReadAllBytes to read only chunks of 1024 bytes.
You can try to use this method to compress file MSDN link
public static void Compress(FileInfo fileToCompress)
{
using (FileStream originalFileStream = fileToCompress.OpenRead())
{
using (FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".gz"))
{
using (GZipStream compressionStream = new GZipStream(compressedFileStream, CompressionMode.Compress))
{
originalFileStream.CopyTo(compressionStream);
}
}
}
}
usage:
string directoryPath = #"c:\users\public\reports";
DirectoryInfo directorySelected = new DirectoryInfo(directoryPath);
foreach (FileInfo fileToCompress in directorySelected.GetFiles())
{
Compress(fileToCompress);
}
I am trying to decompress a byte array and get it into a string using a binary reader. When the following code executes, the inStream position changes from 0 to the length of the array, but str is always an empty string.
BinaryReader br = null;
string str = String.Empty;
using (MemoryStream inStream = new MemoryStream(pByteArray))
{
GZipStream zipStream = new GZipStream(inStream, CompressionMode.Decompress);
BinaryReader br = new BinaryReader(zipStream);
str = br.ReadString();
inStream.Close();
br.Close();
}
You haven't shown how is the data being compressed, but here's a full example of compressing and decompressing a buffer:
using System;
using System.IO;
using System.IO.Compression;
using System.Text;
class Program
{
static void Main()
{
var test = "foo bar baz";
var compressed = Compress(Encoding.UTF8.GetBytes(test));
var decompressed = Decompress(compressed);
Console.WriteLine(Encoding.UTF8.GetString(decompressed));
}
static byte[] Compress(byte[] data)
{
using (var compressedStream = new MemoryStream())
using (var zipStream = new GZipStream(compressedStream, CompressionMode.Compress))
{
zipStream.Write(data, 0, data.Length);
zipStream.Close();
return compressedStream.ToArray();
}
}
static byte[] Decompress(byte[] data)
{
using (var compressedStream = new MemoryStream(data))
using (var zipStream = new GZipStream(compressedStream, CompressionMode.Decompress))
using (var resultStream = new MemoryStream())
{
zipStream.CopyTo(resultStream);
return resultStream.ToArray();
}
}
}