how to do reading of binary files?

Marc 'BlackJack' Rintsch bj_666 at gmx.net
Fri Jun 8 15:19:29 CEST 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



More information about the Python-list mailing list