In <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
wrote:
> I'd like to overwrite just one line of a binary file, based on a
> position set by seek(). Is there no way to do this? As far as I can
> tell I need to read the whole file, change the line, and write it all
> back out. Not exactly easy on the memory, but I see no other solution.
>
> so far:
>
> patchme.seek(offset)
> patchme.write(a2b_hex(edit)) # the data is in hex first
> patchme.close
> print "Patching complete"
>
> This writes the data at the given offset, but _everything_ before it is
> filled with 0's.
Are you sure that you haven't opened the file with the wrong mode? ::
In [69]: f = open('test.dat', 'w')
In [70]: f.seek(1000)
In [71]: f.write('hello')
In [72]: f.close()
In [73]: f = open('test.dat')
In [74]: a = f.read()
In [75]: f.close()
In [76]: a
Out[76]:
'\x00\x00\x00\x00\x00\x00\x00\00<...>hello
If you want to open an existing file without overwriting it you have to
use mode "w+" or "a".
Ciao,
Marc 'BlackJack' Rintsch
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