[Jython-bugs] [ jython-Bugs-1722306 ] OverflowError in UDP Socket Implementation

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Bugs item #1722306, was opened at 2007-05-20 16:24
Message generated for change (Comment added) made by additv
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Category: Library
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: additv (additv)
Assigned to: Nobody/Anonymous (nobody)
Summary: OverflowError in UDP Socket Implementation

Initial Comment:
When using UDP sockets in Jython, calling sendto (socket.py:356) will raise "OverflowError: value too large for byte"
The problematic line is 361:
bytes = jarray.array(map(ord, data), 'b')

This seems to be due to a difference between the results of a call to "ord" and the java defintion of a byte.
Ord returns values between 0 and 255, while a java byte is a value between -128 and 127. 

Thus if a character has an ascii code > 127 this error occurs.

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>Comment By: additv (additv)
Date: 2007-05-21 13:42

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The same bug is in the new socket code, and the same fix can fix it. 
Here's the patch for the updated socket code:

28a29
> import java.lang.String
656c657
<         bytes = jarray.array(map(ord, data), 'b')
---
>         bytes = java.lang.String(data).getBytes("ISO-8859-1")

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Comment By: Charles Groves (cgroves)
Date: 2007-05-21 13:20

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We're replacing socket with a new implementation based on java.nio in
2.2rc1.  It'd be quite helpful if you tested your code with the new
version.  You can drop it in as explained in
http://wiki.python.org/jython/NewSocketModule or just wait for rc1 to come
out.  It should be in a week or two.

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Comment By: additv (additv)
Date: 2007-05-21 13:10

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Here's the patch:

13a14
> import java.lang.String
361c362
<         bytes = jarray.array(map(ord, data), 'b')
---
>         bytes = java.lang.String(data).getBytes("ISO-8859-1")

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Comment By: additv (additv)
Date: 2007-05-21 12:59

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Update: Using java.lang.String mangles characters > 127

if you run:
print java.lang.String('\x80')
it returns 63

running:
ord('\x80')
returns 128 (as it should)

running
print java.lang.String('\x81')


it looks like using:
bytes = java.lang.String(data).getBytes("ISO-8859-1")
works though



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Comment By: additv (additv)
Date: 2007-05-21 12:18

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For some reason the recommended change gives me errors in the data.  
I have found that adding:

import java.lang.String

at the beginning of the file, and changing the line to:

bytes = java.lang.String(data).getBytes()

seems to fix the problem however.

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Comment By: Pekka Laukkanen (laukpe)
Date: 2007-05-21 03:13

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Assuming that the describtion of the problem in the summary is correct it
should be pretty simple to fix this. All that is needed would be changing
the mentioned line to following.

bytes = jarray.array(map(lambda d : ord(d)-128, data), 'b') 

Could you try this with your original data? If it works this could perhaps
be fixed already for 2.2.

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