An example of using scala-conduit for reading a file util a given character is found. See https://github.com/ppetr/scala-conduit

CloseExample.scala

import java.nio._
import java.nio.channels.Channels
import java.io.{ FileInputStream, IOException }
import java.util.zip._
import scala.util.control.Exception._
import conduit._
import conduit.Pipe._

object CloseExample extends App {
    /**
     * Searches a buffer for a character. Rewinds the buffer afterwards.
     */
    def findBuf(c: Byte, buf: ByteBuffer): Option[Int] =
      try {
        while (buf.hasRemaining())
          if (buf.get() == c)
            return Some(buf.position() - 1);
        return None;
      } finally {
        buf.rewind();
      }

    /**
     * Filters buffers until a given character is found. The last buffer
     * (truncated up to the character) is also included.
     */
    def untilPipe(c: Byte): Pipe[ByteBuffer,ByteBuffer,Unit] = {
      // This code doesn't need to finalize anything, so we declare
      // an empty implicit finalizer.
      implicit val fin = Finalizer.empty
      def loop: Pipe[ByteBuffer,ByteBuffer,Unit] =
        requestI((buf: ByteBuffer) =>
          findBuf(c, buf) match {
            case Some(i)  => buf.limit(i); respond(buf); // don't continue
            case None     => respond(buf, loop);
          }
        );
      loop
    }

    val file = "test.gz";
    // Create a new source that chunks a file as ByteBuffer's.
    // (Note that the buffer changes on every step.)
    val source: Source[ByteBuffer,Unit]
      = NIO.readChannel(
          ByteBuffer.allocate(4096),
          Channels.newChannel(new GZIPInputStream(
                                new FileInputStream(file)))
        );
    // Sink that prints bytes to the standard output.
    // You would create your own sink doing whatever you want.
    val sink: Sink[ByteBuffer,Unit]
      = NIO.writeChannel(Channels.newChannel(System.out));

    runPipe(source >-> untilPipe(-1) >-> sink);
}