InputStreamReader buffering issue

Question

I am reading data from a file that has, unfortunately, two types of character encoding.

There is a header and a body. The header is always in ASCII and defines the char

Answer 1

It's even easier:

As you said, your header is always in ASCII. So read the header directly from the InputStream, and when you're done with it, create the Reader with the correct encoding and read from it

private Reader reader;
private InputStream stream;

public void read() {
    int c = 0;
    while ((c = stream.read()) != -1) {
        // Read encoding
        if ( headerFullyRead ) {
            reader = new InputStreamReader( stream, encoding );
            break;
        }
    }
    while ((c = reader.read()) != -1) {
        // Handle rest of file
    }
}