Question

I’m reading a file line by line. The file is encoded by CipherOutputStream and then later compressed by DeflaterOutputStream. The file can consist of UTF-8 characters, like Russian letters, etc.

I want to obtain the offset in actually read file, or the number of bytes read by br.ReadLine() command. The problem is that the file is both encrypted, and deflated, so length of read String is larger than number of read bytes in file.

            InputStream fis=tempURL.openStream();                       //in tempURL I've got an URL to download
            CipherInputStream cis=new CipherInputStream(fis,pbeCipher); //CipherStream
            InflaterInputStream iis=new InflaterInputStream(cis);       //InflaterInputStream
            BufferedReader br = new BufferedReader(
                    new InputStreamReader(iis, "UTF8"));                //BufferedReader
            br.readLine();

            int fSize=tempURL.openConnection().getContentLength();      //Catch FileSize

Answer 1

Use a CountingInputStream from the Apache Commons IO project:

InputStream fis=tempURL.openStream();
CountingInputStream countStream = new CountingInputStream(fis);
CipherInputStream cis=new CipherInputStream(countStream,pbeCipher);
...

Later you can obtain the file position with countStream.getByteCount().