Hi all,
I need some help on the following issue. I can't seem to solve it.
I have a binary (pcl) file.
In this file i want to search for specific codes (like <0C>). I have
tried to solve it by reading the file character by character, but this
is very slow. Especially when it comes to files which are large
(>10MB) this is consuming quite some time.
Does anyone has a hint/clue/solution on this?
thanks already!
Jeroen
7  1579 
jvdb schrieb:
Hi all,
I need some help on the following issue. I can't seem to solve it.
I have a binary (pcl) file.
In this file i want to search for specific codes (like <0C>). I have
tried to solve it by reading the file character by character, but this
is very slow. Especially when it comes to files which are large
(>10MB) this is consuming quite some time.
Does anyone has a hint/clue/solution on this?
What has the searching to do with the reading? 10MB easily fit into the
main memory of a decent PC, so just do
contents = open("file").re ad() # yes I know I should close the file...
print contents.find(' \x0c')
Diez
On 8 jun, 14:07, "Diez B. Roggisch" <d...@nospam.we b.dewrote:
jvdb schrieb:
.......
What has the searching to do with the reading? 10MB easily fit into the
main memory of a decent PC, so just do
contents = open("file").re ad() # yes I know I should close the file...
print contents.find(' \x0c')
Diez
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.
jvdb schrieb:
On 8 jun, 14:07, "Diez B. Roggisch" <d...@nospam.we b.dewrote:
>jvdb schrieb:
......
>What has the searching to do with the reading? 10MB easily fit into the
main memory of a decent PC, so just do
contents = open("file").re ad() # yes I know I should close the file...
print contents.find(' \x0c')
Diez
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_pos ition = 0
positions = []
while last_needle_pos ition != -1:
last_needle_pos ition = contents.find(n eedle, last_needle_pos ition+1)
if last_needle_pos ition != -1:
positions.appen d(last_needle_p osition)
will find all the pagepbreaks. then just slice contents appropriatly.
Did you read the python tutorial?
diez
In <5c************ *@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_pos ition = 0
positions = []
while last_needle_pos ition != -1:
last_needle_pos ition = contents.find(n eedle, last_needle_pos ition+1)
if last_needle_pos ition != -1:
positions.appen d(last_needle_p osition)
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
On 8 jun, 15:19, Marc 'BlackJack' Rintsch <bj_...@gmx.net wrote:
In <5ct0evF31n73.. .@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_pos ition = 0
positions = []
while last_needle_pos ition != -1:
last_needle_pos ition = contents.find(n eedle, last_needle_pos ition+1)
if last_needle_pos ition != -1:
positions.appen d(last_needle_p osition)
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
Hi,
your last comment is also something i have noticed. There are a number
of occasions where this will happen. I also have to deal with this.
I will dive into this on monday, after this hot weekend.
cheers,
Jeroen
On Jun 8, 2:07 am, "Diez B. Roggisch" <d...@nospam.we b.dewrote:
>...
What has the searching to do with the reading? 10MB easily fit into the
main memory of a decent PC, so just do
contents = open("file").re ad() # yes I know I should close the file...
print contents.find(' \x0c')
Diez
Better make that 'open("file", "rb"). This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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