I am trying to compress data using the zlib .net library. Regardless of the content of the uncompressed string I only seem to get two bytes of data in the raw[].
{
string uncompressed = "1234567890";
byte[] data = UTF8Encoding.Default.GetBytes(uncompressed);
MemoryStream input = new MemoryStream(data);
MemoryStream output = new MemoryStream();
Stream outZStream = new ZOutputStream(output,zlibConst.Z_DEFAULT_COMPRESSION);
CopyStream(input, outZStream);
output.Seek(0, SeekOrigin.Begin);
byte[] raw = output.ToArray();
string compressed = Convert.ToBase64String(raw);
}
public void CopyStream(System.IO.Stream input, System.IO.Stream output)
{
byte[] buffer = new byte[2000];
int len;
while ((len = input.Read(buffer, 0, 2000)) > 0)
{
output.Write(buffer, 0, len);
}
output.Flush();
}
The problem here is that the ZOutputStream actually writes some of the information into the stream in the finish() method (which is called by Close). The Close method also closes the base stream, so that is not much use in this situation.
Changing the code to the following should work:
{
string uncompressed = "1234567890";
byte[] data = UTF8Encoding.Default.GetBytes(uncompressed);
MemoryStream input = new MemoryStream(data);
MemoryStream output = new MemoryStream();
ZOutputStream outZStream = new ZOutputStream(output,zlibConst.Z_DEFAULT_COMPRESSION);
CopyStream(input, outZStream);
outZStream.finish();
output.Seek(0, SeekOrigin.Begin);
byte[] raw = output.ToArray();
string compressed = Convert.ToBase64String(raw);
}
public void CopyStream(System.IO.Stream input, System.IO.Stream output)
{
byte[] buffer = new byte[2000];
int len;
while ((len = input.Read(buffer, 0, 2000)) > 0)
{
output.Write(buffer, 0, len);
}
output.Flush();
}
Related
I am trying to decompress the byte array using GZipStream but getting error of "Found invalid data while decoding."
// getting aadhaar sample qr code data from
// https://uidai.gov.in/images/resource/User_manulal_QR_Code_15032019.pdf
static void Main(string[] args)
{
string source = "6979414848205548481619299442879901900893978332594614407044767717485407280104077714658698163325401659212830920734233047578454701810567032015270223682917915825234703754712504887921309181789607809168884583848396456653007022479356336240198130363930881632367124738541517499494458139647378808680614169273221404741476596583953169248831376224396335169577064812987140578144885819479190173537644970232125142253963784979138011318798385442436099901621998283624816070080504830712594525760596934341576755626791590403636878139861665599383319429228364434183913197958738697001410493839281298692342829951566712530309758759364649701153639921979798429707566199261950037418171329283207372048014948669160666776198414040633384677104717697507521717586776709084200364956178863636105988867260929887577092955570407803783021397897341999914616790441029837229129746669225095633201097644321593502503404440714110515167034889128258965583435965030225845348564582051521348800742574442877087774194668983516629631073341202705453382780613775427336949283388084891654484225446940941660942440637784744293259916479841407088189462964489670231866481904237338494872813098890875845640034370370387108798950180220865436012752487216677041817312930119747601017807577565413977545693375480131324240696099879479436722576566447939593195590684591261809038023122178172006150499569185218838749337238281597037288924464009997530938336798176023597292328320965086990184531426188862965408313308973495924965144113396593829090645266653313774582036138982013368561474719154447134894466611560589758251829063226370300282175823479569847261439348404558251402273730865053482214589180028302043821438357583302818374143973997002745047526405755760407045006694423501337081780299815080324840337828812644300041900356816429114261098230198976752026002079876882796597235615015594486182057781476152918170746403157005216896239428521706033466061587608065036133153074432195952131368564234168005447770190345777024917629879639171161719929852078265309160759260989590618158889891835294735614366674503961584445497685736312628248483551986529867423016255476553691922054241686230968975229511700928171281549902682365302333677412951788839806869796040512235899311734337858684531156721416280114473368826463098485252394260075790386415875290922570568686439586036262465414002334117870088922801660529414759784318799843806130096998190881240404138869293309782335305296720666220243304175086358278211355789957998014801209332293458940463859106591986434520433810583569309224929264228263841477378949329312443958215939294432669464260216534074560882723006838459792812340253078330291135526952675203790833430237852831740601433198364243363569730205351077393441691141240055900819091229931605146865520183001810239708464322588389956036291760175558843819105418234580239610174323636606095262722940143706063698846499673285377621180570537788160304936809915237889489342387891057012783726694920184573202789672963922380028271124448024265644396686341508447830351380242127542393849410283830409594988503246799544444687606954881510597515686410993828907588979699141180160893062603338104857903239845856783130275935413569275439908789983311663211937449259444259898972766208";
BigInteger.TryParse(source, out BigInteger numBig);
byte[] bytes = numBig.ToByteArray();
string isoBytes2 = Decompress(bytes);
}
static string Decompress(byte[] gzBuffer)
{
using (MemoryStream ms = new MemoryStream())
{
int msgLength = BitConverter.ToInt32(gzBuffer, 0);
ms.Write(gzBuffer, 0, gzBuffer.Length);
byte[] buffer = new byte[msgLength];
ms.Position = 0;
int length;
using (GZipStream zip = new GZipStream(ms, CompressionMode.Decompress))
{
length = zip.Read(buffer, 0, buffer.Length);
}
var data = new byte[length];
Array.Copy(buffer, data, length);
return Encoding.UTF8.GetString(data);
}
}
In C#, we need to do reverse byte array after coverting byte array from biginteger and before decompression the byte array.
In Java, it not needed.
I'm trying to capture an audio stream in CScore and save it in various encodings and to various locations. One of my intended output encodings is MP3 via the MediaFoundationEncoder APIs.
I am able to successfully encode to MP3 when saving to a local file path. However, if I try to write to a memory stream the memory stream completes writing with a 0 length.
What is wrong with this implementation?
Working Local Storage
var fileName = "c:\audio.mp3";
using (var encoder = MediaFoundationEncoder.CreateMP3Encoder(waveFormat, fileName, waveFormat.BytesPerSecond))
{
byte[] buffer = new byte[waveFormat.BytesPerSecond];
int read;
while ((read = inputStream.Read(buffer, 0, buffer.Length)) > 0)
{
encoder.Write(buffer, 0, read);
}
}
Non-working Memory Stream
using (var outputStream = new MemoryStream())
{
var encoder = MediaFoundationEncoder.CreateMP3Encoder(waveFormat, outputStream, waveFormat.BytesPerSecond);
var buffer = new byte[waveFormat.BytesPerSecond];
int read;
while ((read = inputStream.Read(buffer, 0, buffer.Length)) > 0)
{
encoder.Write(buffer, 0, read);
}
log.Debug("MP3 File Size: " + outputStream.Length); // <-- Returns as 0
}
You have to dispose the encoder after write, this completes the output stream.
public static byte[] EncodeBytes(byte[] bytes, WaveFormat waveFormat)
{
var outputStream = new MemoryStream();
var encoder = MediaFoundationEncoder.CreateMP3Encoder(waveFormat, outputStream, waveFormat.BytesPerSecond);
var buffer = new byte[waveFormat.BytesPerSecond];
var inputStream = new MemoryStream(bytes);
int read;
while ((read = inputStream.Read(buffer, 0, buffer.Length)) > 0)
{
encoder.Write(buffer, 0, read);
}
encoder.Dispose();
return outputStream.ToArray();
}
I was writing a light-weight proxy in c#. When I was decoding the gzip contentEncoding I noted that if I use a small buffer-size(4096) the stream is decoded partially depending the size of the input. Is it a bug in my code or something which is needed to make it work? I set the buffer to 10 MB, and it works okay but defeats my purpose of writing a light-weight proxy.
response = webEx.Response as HttpWebResponse;
Stream input = response.GetResponseStream();
//some other operations on response header
//calling DecompressGzip here
private static string DecompressGzip(Stream input, Encoding e)
{
StringBuilder sb = new StringBuilder();
using (Ionic.Zlib.GZipStream decompressor = new Ionic.Zlib.GZipStream(input, Ionic.Zlib.CompressionMode.Decompress))
{
// works okay for [1024*1024*8];
byte[] buffer = new byte[4096];
int n = 0;
do
{
n = decompressor.Read(buffer, 0, buffer.Length);
if (n > 0)
{
sb.Append(e.GetString(buffer));
}
} while (n > 0);
}
return sb.ToString();
}
Actually, I figured it out. I guess using the string builder causes the problem; instead, I used a memory stream and it works well.
private static string DecompressGzip(Stream input, Encoding e)
{
using (Ionic.Zlib.GZipStream decompressor = new Ionic.Zlib.GZipStream(input, Ionic.Zlib.CompressionMode.Decompress))
{
int read = 0;
var buffer = new byte[4096];
using (MemoryStream output = new MemoryStream())
{
while ((read = decompressor.Read(buffer, 0, buffer.Length)) > 0)
{
output.Write(buffer, 0, read);
}
return e.GetString(output.ToArray());
}
}
}
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
I am writing a C# assembly to take advantage of the GZip functionality in newer versions of the .NET framework, and I am copying code I have used successfully elsewhere.
The way this works is that an application we are using feeds a stream to the assembly, the assembly reads it, compresses it, then returns the compressed result as a string. That string is then put back into the assembly through a stream to uncompress it (normally it will be stored, but I am simply running a basic test).
However, when I feed the string back to the assembly, it errors out while reading it from a byte array that is read from the application's stream. Here is the code:
private void ReadStream(IStream stream, out byte[] data)
{
using (MemoryStream writer = new MemoryStream())
{
IntPtr rwBytes = Marshal.AllocHGlobal(4);
int _rwBytes = 0;
data = new byte[0xafc8];
do
{
stream.Read(data, 0xafc8, rwBytes);
_rwBytes = Marshal.ReadInt32(rwBytes);
writer.Write(data, 0, _rwBytes);
}
while (_rwBytes > 0);
writer.Close();
Marshal.FreeHGlobal(rwBytes);
}
}
public string CompressString([In, MarshalAs(UnmanagedType.AsAny)] object appStream)
{
byte[] buffer = null;
ReadStream(appStream as IStream, out buffer);
MemoryStream ms = new MemoryStream();
using (GZipStream zip = new GZipStream(ms, CompressionMode.Compress, true))
{
zip.Write(buffer, 0, buffer.Length);
}
ms.Position = 0;
MemoryStream outStream = new MemoryStream();
byte[] compressed = new byte[ms.Length];
ms.Read(compressed, 0, compressed.Length);
byte[] gzBuffer = new byte[compressed.Length + 4];
System.Buffer.BlockCopy(compressed, 0, gzBuffer, 4, compressed.Length);
System.Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gzBuffer, 0, 4);
string str = Convert.ToBase64String(gzBuffer);
gzBuffer = Convert.FromBase64String(str);
return str;
}
public string DecompressString([In, MarshalAs(UnmanagedType.AsAny)] object appStream)
{
byte[] buffer = null;
ReadStream(appStream as IStream, out buffer);
string compressedText = Encoding.UTF8.GetString(buffer);
byte[] gzBuffer = Convert.FromBase64String(compressedText);
using (MemoryStream ms = new MemoryStream())
{
int msgLength = BitConverter.ToInt32(gzBuffer, 0);
ms.Write(gzBuffer, 4, gzBuffer.Length - 4);
buffer = new byte[msgLength];
ms.Position = 0;
using (GZipStream zip = new GZipStream(ms, CompressionMode.Decompress))
{
zip.Read(buffer, 0, buffer.Length);
}
}
return Encoding.UTF8.GetString(buffer);
}
The string is returned from the CompressString function as:
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
When it is read back from the stream in the Encoding.UTF8.GetString call, it is:
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
These strings are identical. I can even convert it back and forth in the CompressString function with no problem. Any thoughts out there? This is very strange.
Don't use UTF8, you should use the ascii text encoding instead. When you get the bytes from your string, you'll end up with some extra bytes due to the way UTF strings are encoded.