c# - GZipStream with large files doesn't work well -

i want compress large gml files (1-10gb). wrote method this, not work well. if decompress using 7-zip windows (or else), file looks bad in end (it's not finished, xml not finished)... don't see i'm doing wrong...

private void compressfile() {     string outputpath = path.combine(path.changeextension(_gmlpath, ".gz"));      var buffer = new byte[1024 * 64];     using (var compressing = new gzipstream(file.openwrite(outputpath), compressionmode.compress))     {         using (var file = file.openread(_gmlpath))         {             var bytesread = file.read(buffer, 0, buffer.length);             while (bytesread != 0)             {                 compressing.write(buffer, 0, buffer.length);                 bytesread = file.read(buffer, 0, buffer.length);             }         }     } } 

[edit]

additional question: how can specify/change name of file, compressed inside gz? it's name same input's one, there no .gml extention:s (there in input)...

var bytesread = file.read(buffer, 0, buffer.length); 

reads between 1 , 65536 bytes, but

compressing.write(buffer, 0, buffer.length); 

always writes 65536 bytes, you're ending junk in file if read less 65536 bytes.

solution: write bytesread many bytes.

compressing.write(buffer, 0, bytesread);