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Groups > comp.lang.java.programmer > #38034
| From | Eric Sosman <esosman@comcast-dot-net.invalid> |
|---|---|
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: bit package |
| Date | 2018-02-17 11:12 -0500 |
| Organization | A noiseless patient Spider |
| Message-ID | <p69k92$po7$1@dont-email.me> (permalink) |
| References | <bebd1080-35be-485d-ac9d-f7e2d4b361da@googlegroups.com> <p696af$tiv$1@dont-email.me> <c08311e7-0ff3-46b8-823a-0b89b3b312ac@googlegroups.com> |
On 2/17/2018 10:51 AM, Philipp Kraus wrote:
> Am Samstag, 17. Februar 2018 13:14:22 UTC+1 schrieb Eric Sosman:
>> 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.
>>
>
> I'm searching something like Node.JS Buffer for Java
> https://nodejs.org/api/buffer.html
... which documents no set() or get() methods. ;-)
In addition to java.nio.ByteBuffer, take a look at
java.io.DataOutput and the classes that implement it. These
latter will require additional effort if you must deal with
endianness issues, but the effort should be minimal.
--
esosman@comcast-dot-net.invalid
One thousand sixty-eight days to go.
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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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