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Groups > comp.lang.java.programmer > #38027

Re: bit package

From Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups comp.lang.java.programmer
Subject Re: bit package
Date 2018-02-17 07:14 -0500
Organization A noiseless patient Spider
Message-ID <p696af$tiv$1@dont-email.me> (permalink)
References <bebd1080-35be-485d-ac9d-f7e2d4b361da@googlegroups.com>

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On 2/17/2018 3:33 AM, Philipp Kraus wrote:
> Hello,
> 
> I'm building a network communication protocol for hardware-communication, so I need a bit representation of my dara like a C struct:
> 
> struct
> {
>      unint8 field1;
>      unint16 field2;
> ...
> }

     Aside: This approach won't always work, not even in C.  (Think
padding bytes, endianness, ...)

> On my Java classes I have got int, long, ... so how can I create such bit structures?
> My first try is to use a BitSet and convert all datatypes manually, but is there a better possibility to create such bit sequences. I need a sending and receiving structure. I'm working with Java 9.
> 
> I the best case I create an object like
> 
> BitObject l_obj = new BitObject( 8, 16, 8, 32 );
> l_object.set(0, mybyte)
> l_object.set(1, myshort)
> l_object.set(2, mybyte)
> l_object.set(3,  myint)
> 
> and on reseiving
> 
> BitObject l_obj = new BitObject( mybytearray_from_socket, 8, 16, 8, 32 );
> l_obj.get(0)
> l_obj.get(1)
> ...
> 
> Can you suggest a library or anything for doing this?

     It's not clear to me precisely what you're trying to do (the
semantics of l_object.set() are not obvious), but I think you might
find java.nio.ByteBuffer a good starting place.

-- 
esosman@comcast-dot-net.invalid
One thousand sixty-eight days to go.

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Thread

bit package Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2018-02-17 00:33 -0800
  Re: bit package Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-02-17 07:14 -0500
    Re: bit package Kiwi User <martin@mydomain.invalid> - 2018-02-17 12:40 +0000
      Re: bit package Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-02-17 08:16 -0500
    Re: bit package Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2018-02-17 07:51 -0800
      Re: bit package Arne Vajhøj <arne@vajhoej.dk> - 2018-02-17 11:11 -0500
        Re: bit package Philipp Kraus <philipp.kraus.flashpixx@gmail.com> - 2018-02-17 11:41 -0800
          Re: bit package Arne Vajhøj <arne@vajhoej.dk> - 2018-02-17 14:55 -0500
      Re: bit package Eric Sosman <esosman@comcast-dot-net.invalid> - 2018-02-17 11:12 -0500
        Re: bit package Arne Vajhøj <arne@vajhoej.dk> - 2018-02-17 12:27 -0500
      Re: bit package Daniele Futtorovic <da.futt.news@laposte.net> - 2018-02-17 20:55 +0100
  Re: bit package Robert Klemme <shortcutter@googlemail.com> - 2018-02-17 16:23 +0100
  Re: bit package Arne Vajhøj <arne@vajhoej.dk> - 2018-02-17 10:25 -0500

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