Implicit byte swap on array.fromfile()?

[Arlindo da Silva]

All,

  I'm porting some scripts from CPython to Jython and I am running into some I/O issue that perhaps someone could clarify whether this is a bug or a feature of jython v2.2.1. Basically, I am loading some floats from a binary stream into an array. Something like,

import array
a = array.array('f')
a.fromfile(Reader,10)

where Reader is actually the stdout of a C program captured with popen2():

Reader, Writer = popen2(cmdline,bufsize=0)

On CPython 2.5 I get the values as expected. Under jython, the numbers are byte swapped, that is, a.byteswap() produce the correct values. It appears that somewhere along jython is assuming that the Reader stream is in network byte order and doing the swap for me.  Not surprisingly, I have no problem getting strings from Reader.

Is there a way for me to disable this automatic byte swap when reading floats?

   Thank you,

         Arlindo
  
--
Arlindo da Silva
dasilva@...
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[Arlindo da Silva]

All,

  I just realized that on both Mac OS X 8.5/Intel and Linux/Ubuntu 8.04 I  always get os.byteorder='big' with Jython, while CPython gives me os.byteorder='little' as expected.  This is probably a reflection of the fact that the JVM is big-endian regardless of the endianess of the underlying hardware. This could explain the automatic byteswapping in my original posting. Can someone confirm this?

  Arlindo

On Thu, Jun 19, 2008 at 2:12 PM, Arlindo da Silva <dasilva@...> wrote:

All,

  I'm porting some scripts from CPython to Jython and I am running into some I/O issue that perhaps someone could clarify whether this is a bug or a feature of jython v2.2.1. Basically, I am loading some floats from a binary stream into an array. Something like,

import array
a = array.array('f')
a.fromfile(Reader,10)

where Reader is actually the stdout of a C program captured with popen2():

Reader, Writer = popen2(cmdline,bufsize=0)

On CPython 2.5 I get the values as expected. Under jython, the numbers are byte swapped, that is, a.byteswap() produce the correct values. It appears that somewhere along jython is assuming that the Reader stream is in network byte order and doing the swap for me.  Not surprisingly, I have no problem getting strings from Reader.

Is there a way for me to disable this automatic byte swap when reading floats?

   Thank you,

         Arlindo
  
--
Arlindo da Silva
dasilva@...

--
Arlindo da Silva
dasilva@...

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[Balbir.Kaur]

Hi,

I am trying to import hashlib in my jython script......and getting error msg

No Module named _md5

Here is traceback result

File C:\Python25\Lib\hashlib.py line 60 in _get_built_constructor

File C:\Python25\Lib\hashlib.py Line 133
no module named -md5

my current directory is c:\grinder-3.0.1

If this is standard problem of importing Python modules in Jython (like parsers, XMLstring)....is there a way to use same Hash sha1 functionality in Jython ..may be using Java ?

can someone please share that recipe.

Thanks

-Balbir

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[Moore, Greg]

Some parts of this message have been removed. Learn more about Nabble's security policy.

Hi,

 

Jython 2.2 currently only supports Jython 2.2 and a little 2.3 stuff. Python 2.5 will be supported when Jython 2.5 is released sometime in the future.

So importing python 2.5 modules into the current Jython more than likely won’t work. I’d recommend using a Java lib. But which one, I don’t know maybe google will help you there.

 

Greg.

 

From: jython-users-bounces@... [mailto:jython-users-bounces@...] On Behalf Of Balbir.Kaur@...
Sent: Friday, June 20, 2008 11:19 AM
To: jython-users@...
Subject: [Jython-users] import error in hashlib
Importance: High

 

Hi,

I am trying to import hashlib in my jython script......and getting error msg

No Module named _md5

Here is traceback result

File C:\Python25\Lib\hashlib.py line 60 in _get_built_constructor

File C:\Python25\Lib\hashlib.py Line 133
no module named -md5

my current directory is c:\grinder-3.0.1

If this is standard problem of importing Python modules in Jython (like parsers, XMLstring)....is there a way to use same Hash sha1 functionality in Jython ..may be using Java ?

can someone please share that recipe.

Thanks

-Balbir

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[Charlie Groves]

On Fri, Jun 20, 2008 at 11:19 AM,  <Balbir.Kaur@...> wrote:
> I am trying to import hashlib in my jython script......and getting error msg
>
> No Module named _md5

Jython 2.2 does have the sha module:
http://docs.python.org/lib/module-sha.html  You'll want to update to
hashlib when things move to 2.5, but you should be able to import sha
directly for now.

Charlie

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