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From: Jan Burse <janburse@fastmail.fm>
Newsgroups: comp.lang.java.programmer
Subject: Re: Piggypack Encoding/Decoding on RandomAccessFile
Date: Thu, 03 Nov 2011 23:24:09 +0100
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Jan Burse schrieb:
> Should I mingle with file descriptor, and get
> associated input and output streams, and then
> move forward?

BTW: The file descriptor route works as follows:


     RandomAccessFile raf = new RandomAccessFile(..., "r");
     FileInputStream fi = new FileInputStream(raf.getFD());

     ... change file position ...

     ... piggypack a InputStreamReader ...

     ... change file position ...

     ... piggypack another InputStreamReader ...

     fi.close();
     raf.close();

Works also for FileOutputStream.

But I am not sure whether it is the prefered route...

Also since javadoc for InputStreamReader says:

	"To enable the efficient conversion of bytes to
	characters, more bytes may be read ahead
	from the underlying stream than are necessary
	to satisfy the current read operation."

Reading the file position after some read from InputStreamReader
will probably not give a reliable position.

But advantage over a normal InputStreamReader, which has only
a skip(), would be for example that a rewind() can be implemented
via a seek(0).

Bye