Planet PDF Forum Archive

Planet PDF ForumWowsers! This is page is old, head to the LIVE Planet PDF Forum. It features more than 10 conferences, covering everything from beginner to in-depth developer and pre-press discussions. If you wish to continue... one & two archive covers 1999-2011 (160,000 pages).

New Forum | Previous | Next | (P-PDF) Developers

Topic: Need help on Zlib
Conf: (P-PDF) Developers, Msg: 51055
From: skajan
Date: 5/29/2002 04:42 PM

Hi Genies

I have met a deadlock in my project because i am trying to use zlib.
Actually what i am trying to do is replace a text in the pdf which is using
Flate decode. I am explaining here in detail.

a) what we are doing in order to replace the text?

1) Extract the data between stream/endstream
2) Decompress it in memory
3) Search for "Shan Kajendran" in memory block
4) Replace it with "Leonard Rosenthol"
5) Compress the memory block using zlib
6) Put that compressed data back between the stream/endstream
7) Update /Length
8) Update the Xref table

b)what is the outcome ?
Blank pdf

c) what i have noticed ?

Zlib compressed pattern is different. The first character is starting
with 'x'.
Where all PDF files containing streams that have been encoded by Flate
starts with ASCII CODE 72 (H)
and followed by ASCII CODE 137 (PERTHOUSAND) character.Is this some kind
of BOD marker ?
If that's the case how do we incorporate this into the compressed stream
(Please see attached text file which decompressed and compressed the same
content stream without any modifications.)

b) Is compressed data (using zlib) should have the same pattern as PDF?

c) What settings we have to do?

At present i am doing as follows ( Thanks Leonard & Aandi)

deflateInit() to start, deflate() for each chunk of data
(with Z_NO_FLUSH set), and then deflateEnd() when we are done.

I am glad to send you the test code if someone ready to help me to pointout
where i am making mistake.

Thanks in advance
Shan Kajendran

(File attachment removed)

PDF In-Depth Free Product Trials Ubiquitous PDF

Debenu Aerialist

The ultimate plug-in for Adobe Acrobat. Advanced splitting, merging, stamping, bookmarking, and link...

Download free demo

Debenu PDF Tools Pro

It's simple to use and will let you preview and edit PDF files, it's a Windows application that makes...

Download free demo

Five visions of a PDF Day

In the world of PDFs or as we like to say Planet (of) PDF, a year isn't a real PDF year without an intense few days of industry knowledge sharing.

May 15, 2018
Platinum Sponsor

Search Planet PDF
more searching options...
Planet PDF Newsletter
Most Popular Articles
Featured Product

Debenu PDF Aerialist

The ultimate plug-in for Adobe Acrobat. Advanced splitting, merging, stamping, bookmarking, and link control. Take Acrobat to the next level.


Adding a PDF Stamp Comment

OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.