bitconverter

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6 total messages Started by Roy Blinng Thu, 05 Jun 2003 18:06

#553

Author: Roy Blinng
Date: Thu, 05 Jun 2003 18:06

6 lines
1117 bytes

hi,
which java package should import to use bitconverting routines?
how can i also convert byte[] to double? double to byte[]?
if i read a blob data from database and convert that byte[] to double,
will there be a bigendian or little endian problem? how can i solve this?
thanks,

Re: bitconverter

#554

Author: Kevin Dean
Date: Thu, 05 Jun 2003 19:35

26 lines
2036 bytes

In short, you can't.  Java doesn't deal with big-endian and little-endian
issues because it guarantees that the external representation of all integer
types is portable across JVM's.  Similarly, it doesn't give you direct
access to pointer address or array bases.  What exactly are you trying to
do?

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"Roy Blinng" <royb45108@hotmail.com> wrote in message
news:3edf86be@newsgroups.borland.com...
> hi,
> which java package should import to use bitconverting routines?
> how can i also convert byte[] to double? double to byte[]?
> if i read a blob data from database and convert that byte[] to double,
> will there be a bigendian or little endian problem? how can i solve this?
> thanks,
>
>

Re: bitconverter

#555

Author: Roy Blinng
Date: Thu, 05 Jun 2003 20:01

9 lines
1395 bytes

I will read a blob data from my database to a variable byte[].
then i will convert that byte[] to double.

>because it guarantees that the external representation
>of all integer
Does this blob data contain the information about which significant byte is
stored first? if not, it wouldnt be a good solution for converting byte[] to
double.
Regards,

Re: bitconverter

#556

Author: Kevin Dean
Date: Thu, 05 Jun 2003 21:55

30 lines
2126 bytes

If you're reading a blob from a database, it will be restored in the byte
array in the order in which it was stored in the database; there is no
conversion of any form.  As for parsing out doubles etc. from it, I'm afraid
I can't think of any way for doing that.

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"Roy Blinng" <royb45108@hotmail.com> wrote in message
news:3edfa0df@newsgroups.borland.com...
> I will read a blob data from my database to a variable byte[].
> then i will convert that byte[] to double.
>
> >because it guarantees that the external representation
> >of all integer
> Does this blob data contain the information about which significant byte
is
> stored first? if not, it wouldnt be a good solution for converting byte[]
to
> double.
> Regards,
>
>

Re: bitconverter

#557

Author: John McGrath TeamB
Date: Fri, 06 Jun 2003 04:29

17 lines
1577 bytes

On Thu, 5 Jun 2003 17:55:39 -0400, Kevin Dean wrote:

> As for parsing out doubles etc. from it, I'm afraid
> I can't think of any way for doing that.

You can do that by packing the bytes into a long value in the order of 
your choosing using shift and masking operators and then converting the 
long value to a double using Double.longBitsToDouble().

-- 
Regards,

John McGrath [TeamB]

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Re: bitconverter

#559

Author: Kevin Dean
Date: Fri, 06 Jun 2003 11:36

32 lines
2255 bytes

Thanks John.  I've never had a need to do that kind of bit manipulation in
Java but it's nice to know it's there.  That will come in handy someday.

-- 
Check out our latest white papers at
http://www.datadevelopment.com/papers/index.html

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Team Development with JBuilder and Borland Enterprise Server

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http://www.datadevelopment.com/

"John McGrath [TeamB]" <ng-b@JPMcGrath.net> wrote in message
news:MPG.1949e2cadcc6a3f598bfd3@newsgroups.borland.com...
> On Thu, 5 Jun 2003 17:55:39 -0400, Kevin Dean wrote:
>
> > As for parsing out doubles etc. from it, I'm afraid
> > I can't think of any way for doing that.
>
> You can do that by packing the bytes into a long value in the order of
> your choosing using shift and masking operators and then converting the
> long value to a double using Double.longBitsToDouble().
>
> -- 
> Regards,
>
> John McGrath [TeamB]
>
> ---------------------------------------------------
> Before sending me e-mail, please read:
>     http://www.JPMcGrath.net/newsgroups/e-mail.html

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