Reading from a socket: first characters, then octets

  When a client sends an HTTP PUT request to my web server,
  I start to read characters from the socket:

this.br =
new java.io.BufferedReader
( new java.io.InputStreamReader
  ( socket.getInputStream(), "ANSI_X3.4-1968" ));

  But sometimes, after the initial text, the socket will
  change to emit binary data (octets), that is, it will
  send me the actual data of the PUT request during the
  same transmission (TCP session).

  The read()-method of the InputStreamReader will give
  me a converted character. But I need unconverted octets
  from this point on. With the above code, Java will
  convert some octets and modify their values, so that
  the binary data will become corrupted.

  When I start then to use the read()-method of the
  socket.getInputStream(), I might miss some octets which where
  already read by the InputStreamReader or the BufferedReader.
  But I also want to have buffering, because I/O usually is
  slower without buffering.

  Is there already a well-known solution to such a problem,
  that is, switch from text to binary mode when reading from
  a socket?

  One possibility would be an encoding name that hints to
  Java to treat 0A and 0D as line seperators, but otherwise
  not to modify octet values, when converting octets to
  characters. Then I could read the octets as characters.
  (Or do I have to write a custom CharsetDecoder for this?)