I am newbie in .net. I am doing compression and decompression string in C#. There is a XML and I am converting in string and after that I am doing compression and decompression.There is no compilation error in my code except when I decompression my code and return my string, its returning only half of the XML.
Below is my code, please correct me where I am wrong.
Code:
class Program
{
public static string Zip(string value)
{
//Transform string into byte[]
byte[] byteArray = new byte[value.Length];
int indexBA = 0;
foreach (char item in value.ToCharArray())
{
byteArray[indexBA++] = (byte)item;
}
//Prepare for compress
System.IO.MemoryStream ms = new System.IO.MemoryStream();
System.IO.Compression.GZipStream sw = new System.IO.Compression.GZipStream(ms, System.IO.Compression.CompressionMode.Compress);
//Compress
sw.Write(byteArray, 0, byteArray.Length);
//Close, DO NOT FLUSH cause bytes will go missing...
sw.Close();
//Transform byte[] zip data to string
byteArray = ms.ToArray();
System.Text.StringBuilder sB = new System.Text.StringBuilder(byteArray.Length);
foreach (byte item in byteArray)
{
sB.Append((char)item);
}
ms.Close();
sw.Dispose();
ms.Dispose();
return sB.ToString();
}
public static string UnZip(string value)
{
//Transform string into byte[]
byte[] byteArray = new byte[value.Length];
int indexBA = 0;
foreach (char item in value.ToCharArray())
{
byteArray[indexBA++] = (byte)item;
}
//Prepare for decompress
System.IO.MemoryStream ms = new System.IO.MemoryStream(byteArray);
System.IO.Compression.GZipStream sr = new System.IO.Compression.GZipStream(ms,
System.IO.Compression.CompressionMode.Decompress);
//Reset variable to collect uncompressed result
byteArray = new byte[byteArray.Length];
//Decompress
int rByte = sr.Read(byteArray, 0, byteArray.Length);
//Transform byte[] unzip data to string
System.Text.StringBuilder sB = new System.Text.StringBuilder(rByte);
//Read the number of bytes GZipStream red and do not a for each bytes in
//resultByteArray;
for (int i = 0; i < rByte; i++)
{
sB.Append((char)byteArray[i]);
}
sr.Close();
ms.Close();
sr.Dispose();
ms.Dispose();
return sB.ToString();
}
static void Main(string[] args)
{
XDocument doc = XDocument.Load(@"D:\RSP.xml");
string val = doc.ToString(SaveOptions.DisableFormatting);
val = Zip(val);
val = UnZip(val);
}
}
My XML size is 63KB.
Best Answer
The code to compress/decompress a string
Remember that
Zip
returns abyte[]
, whileUnzip
returns astring
. If you want a string fromZip
you can Base64 encode it (for example by usingConvert.ToBase64String(r1)
) (the result ofZip
is VERY binary! It isn't something you can print to the screen or write directly in an XML)The version suggested is for .NET 2.0, for .NET 4.0 use the
MemoryStream.CopyTo
.IMPORTANT: The compressed contents cannot be written to the output stream until the
GZipStream
knows that it has all of the input (i.e., to effectively compress it needs all of the data). You need to make sure that youDispose()
of theGZipStream
before inspecting the output stream (e.g.,mso.ToArray()
). This is done with theusing() { }
block above. Note that theGZipStream
is the innermost block and the contents are accessed outside of it. The same goes for decompressing:Dispose()
of theGZipStream
before attempting to access the data.