C # merge large files

Public static bool splitfile (string sourcefile, int nnooffiles)
{
Bool split = false;

Try
{

Filestream FS = new filestream (sourcefile, filemode. Open, fileaccess. Read );
Int sizeofeachfile = (INT) math. Ceiling (double) fs. Length/nnooffiles );

For (INT I = 0; I <= nnooffiles; I ++)
{
String basefilename = path. getfilenamewithoutextension (sourcefile );
String extension = path. getextension (sourcefile );

Filestream outputfile = new filestream (path. getdirectoryname (sourcefile) + "\" + basefilename + "." +
I. tostring (). padleft (5, convert. tochar ("0") + extension + ". tmp", filemode. Create, fileaccess. Write );

Int bytesread = 0;
Byte [] buffer = new byte [sizeofeachfile];

If (bytesread = FS. Read (buffer, 0, sizeofeachfile)> 0)
{
Outputfile. Write (buffer, 0, bytesread );
}

Outputfile. Close ();

}
FS. Close ();
}
Catch (exception ex)
{
Throw ex;
}

Return split;
}

Public static bool mergefile (string inputfilefolder)
{
Bool output = false;

Try
{
String [] tmpfiles = directory. getfiles (inputfilefolder, "*. tmp ");

Filestream outputfile = NULL;
String prevfilename = "";

Foreach (string tempfile in tmpfiles)
{
String filename = path. getfilenamewithoutextension (tempfile );
String basefilename = filename. substring (0, filename. indexof (convert. tochar (".")));
String extension = path. getextension (filename );

If (! Prevfilename. Equals (basefilename ))
{
If (outputfile! = NULL)
{
Outputfile. Flush ();
Outputfile. Close ();
}
Outputfile = new filestream (inputfilefolder + "\" + basefilename + extension, filemode. openorcreate, fileaccess. Write );

}

Int bytesread = 0;
Byte [] buffer = new byte [1024];
Filestream inputtempfile = new filestream (tempfile, filemode. openorcreate, fileaccess. Read );

While (bytesread = inputtempfile. Read (buffer, 0, 1024)> 0)
Outputfile. Write (buffer, 0, bytesread );

Inputtempfile. Close ();
File. Delete (tempfile );
Prevfilename = basefilename;

}

Outputfile. Close ();
}
Catch (exception ex)
{
Throw ex;
}

Return output;
}