To turn a signed byte (-128 to 127) into an unsigned one:
(bit-and the-byte 0xff)
The byte (for example 0x80, which is negative) will be extended to an
int (0xff80) and anded with 0x00ff (and you get 0x0080,
which is positive).
The javadoc for the methods of DataInput[1] contain form
Thanks for the help. Sorry I got agitated about this - it was just
that my code (that was doing lots of byte handling) worked with a
previous version of clojure and then stopped working.
Thanks Ken, I shall use your little workaround.
On Feb 12, 10:04 pm, Ken Wesson wrote:
> On Sat, Feb 12, 2011
On Sat, Feb 12, 2011 at 4:54 PM, Aaron Cohen wrote:
> On Sat, Feb 12, 2011 at 4:42 PM, Ken Wesson wrote:
>> On Sat, Feb 12, 2011 at 8:28 AM, timc wrote:
>>> (def b (byte i))
>>>
>>> is doing something equivalent to this internally:
>>>
>>> byte b = Byte.parseByte(String.format("%d",i));
>>
>> Wh
On Sat, Feb 12, 2011 at 4:42 PM, Ken Wesson wrote:
> On Sat, Feb 12, 2011 at 8:28 AM, timc wrote:
>> Further investigation reveals that
>>
>> (def b (byte i))
>>
>> is doing something equivalent to this internally:
>>
>> byte b = Byte.parseByte(String.format("%d",i));
>
> What the HELL?
>
> That'
On Sat, Feb 12, 2011 at 8:28 AM, timc wrote:
> Further investigation reveals that
>
> (def b (byte i))
>
> is doing something equivalent to this internally:
>
> byte b = Byte.parseByte(String.format("%d",i));
What the HELL?
That's incredibly icky and inefficient. :)
Why not
if (i < 128 || i >
On Feb 12, 2011, at 6:53 AM, Aaron Cohen wrote:
On Sat, Feb 12, 2011 at 8:28 AM, timc wrote:
Further investigation reveals that
(def b (byte i))
is doing something equivalent to this internally:
byte b = Byte.parseByte(String.format("%d",i));
which does indeed throw a NumberFormatExceptio
On Fri, Feb 11, 2011 at 12:22 PM, timc wrote:
> How on earth is one supposed to do communication programming (not to
> mention handling binary files etc) without an unsigned byte type?
>
> I see that this issue has been talked about vaguely - is there a
> solution?
>
> Thanks
>
>
Java guarantees
I should also mention that for this sort of stuff, people often get
tired of raw bit-twiddling and move to something like a wrapper around
protocol buffers (such as https://github.com/ninjudd/clojure-protobuf)
or a DSL such as gloss (https://github.com/ztellman/gloss/wiki).
--Aaron
--
You receiv
On Sat, Feb 12, 2011 at 8:28 AM, timc wrote:
> Further investigation reveals that
>
> (def b (byte i))
>
> is doing something equivalent to this internally:
>
> byte b = Byte.parseByte(String.format("%d",i));
>
> which does indeed throw a NumberFormatException if the decimal integer
> representati
Further investigation reveals that
(def b (byte i))
is doing something equivalent to this internally:
byte b = Byte.parseByte(String.format("%d",i));
which does indeed throw a NumberFormatException if the decimal integer
representation given to it produces an out-of-range value (as it
should).
Sorry I did not make myself clear - I thought it was obvious given the
previous postings on this subject.
This java program:
public class TestByte {
public static void main(String[] args)
{
int i = 0x123456ab;
byte[] b = new byte[1];
I have to deal with them when processing AMF packets, and I use the
Netty library - it's amazing, you should look into it.
http://www.jboss.org/netty
-Rich
On Fri, Feb 11, 2011 at 10:22 AM, timc wrote:
> How on earth is one supposed to do communication programming (not to
> mention handling bi
Well, until you start doing "bit-shift-right"s and the sign bit (high
bit) doesn't go to 0 after shifting it down. Actually you typically
need to represent individual bytes as ints and write them back out
using writeByte() when you're trying to do low level bit-twiddling.
It's a pain but it works.
On Fri, Feb 11, 2011 at 20:34, Stuart Sierra
wrote:
> Java doesn't have any unsigned types, and that's not really something we can
> change. Java libraries that need to do binary I/O tend to work with byte
> arrays and handle individual bytes as ints.
> -Stuart Sierra
> clojure.com
Well, except
Java doesn't have any unsigned types, and that's not really something we can
change. Java libraries that need to do binary I/O tend to work with byte
arrays and handle individual bytes as ints.
-Stuart Sierra
clojure.com
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Gr
> How on earth is one supposed to do communication programming (not to
> mention handling binary files etc) without an unsigned byte type?
>
> I see that this issue has been talked about vaguely - is there a
> solution?
>
http://www.darksleep.com/player/JavaAndUnsignedTypes.html ?
--
You
What can you not do with the signed byte type and arrays of bytes
(Java byte[] and Clojure (byte-array ...))?
I believe these are frequently used for Java I/O, and can be used for
Clojure I/O as well.
Andy
On Feb 11, 2011, at 9:22 AM, timc wrote:
How on earth is one supposed to do commun
How on earth is one supposed to do communication programming (not to
mention handling binary files etc) without an unsigned byte type?
I see that this issue has been talked about vaguely - is there a
solution?
Thanks
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