Groups > comp.lang.java.programmer > #38028

Re: bit package

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Subject	Re: bit package
Date	Sat, 17 Feb 2018 12:40:35 +0000 (UTC)
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On Sat, 17 Feb 2018 07:14:05 -0500, Eric Sosman wrote:

> 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.

The BitSet class looks fairly straight forward and is explicitly little 
endian.

I can't comment on BitObject because I'm using OpenJava 8, the current 
version for RedHat Fedora 27. This doesn't provide a BitObject class.


-- 
Martin    | martin at
Gregorie  | gregorie dot org

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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