Re: [ctypes-users] Initialising a struct from a buffer

[Thomas H. <th...@ct...>]

Bradley Schatz schrieb:
> Hi,
> 
> Is there a simple way to initialise a struct from a buffer containing
> bytes, without first copying the contents of the buffer into a ctypes
> string buffer? I am currently doing the following to initialise my
> object (python 2.5 ctypes). buf is the result of a read on a file
> descriptor.
> 
>                 ptr =
> ctypes.create_string_buffer(self.buf[offset:offset+ctypes.sizeof(EndCentralDirectory)])
>                 self.end = EndCentralDirectory()
>                 ctypes.memmove(ctypes.byref(self.end), ptr,
> ctypes.sizeof(EndCentralDirectory))
> 
> Im sure there is a simpler way to do this, but it is eluding me. Suggestions?

Well, Python 2.6's ctypes has .from_buffer and .from_buffer_copy
class methods.  Since you're using 2.5, you have to get the address
of the buffer (as integer) and then pass it to the .from_address class method.
The Structure instance will then be valid as long as the source object.

-- 
Thanks,
Thomas