Implementing file reading in C/Python

James Mills prologic at shortcircuit.net.au
Fri Jan 9 05:16:05 CET 2009


On Fri, Jan 9, 2009 at 1:04 PM, Johannes Bauer <dfnsonfsduifb at gmx.de> wrote:
> Hello group,

Hello.

(...)

> Which takes about 40 seconds. I want the niceness of Python but a little
> more speed than I'm getting (I'd settle for factor 2 or 3 slower, but
> factor 30 is just too much).
>
> Can anyone point out how to solve this efficiently in Python?

Johannes, your 2 programs, 1 in Python and the
other in C do _not_ produce the same result.

I have tested this against a randomly generated
file from /dev/urandom (10M). Yes the Python
one is much slower, but I believe it's bebcause
the Python implementation is _correct_ where
teh C one is _wrong_ :)

The resulting test.bin.pgm from python is exactly
3.5M (from 10M). The resulting test.bin.pgm from
the C version is 16K.

Something is not quite right here :)

cheers
James



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