how to do reading of binary files?
Marc 'BlackJack' Rintsch
bj_666 at gmx.net
Fri Jun 8 09:19:29 EDT 2007
In <5ct0evF31n730U1 at mid.uni-berlin.de>, Diez B. Roggisch wrote:
> jvdb schrieb:
>> True. But there is another issue attached to the one i wrote.
>> When i know how much this occurs, i know the amount of pages in the
>> file. After that i would like to be able to extract a given amount of
>> data:
>> file x contains 20 <0C>. then for example i would like to extract from
>> instance 5 to instance 12 from the file.
>> The reason why i want to do this: The 0C stands for a pagebreak in PCL
>> language. This way i would be absle to extract a certain amount of
>> pages from the file.
>
> And? Finding the respective indices by using
>
> last_needle_position = 0
> positions = []
> while last_needle_position != -1:
> last_needle_position = contents.find(needle, last_needle_position+1)
> if last_needle_position != -1:
> positions.append(last_needle_position)
>
>
> will find all the pagepbreaks. then just slice contents appropriatly.
> Did you read the python tutorial?
Maybe splitting at '\x0c', selecting/slicing the wanted pages and joining
them again is enough, depending of the size of the files and memory of
course.
One problem I see is that '\x0c' may not always be the page end. It may
occur in "rastered image" data too I guess.
Ciao,
Marc 'BlackJack' Rintsch
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