[poppler] How to "pdfunite" in memory...?

[Pierre Couderc]

On 7/17/21 8:43 PM, Oliver Sander wrote:
>> I do not understand well your question. But I know that a pdf 
>> document contains pages.
>>
>> I have pdf documents in memory (read from a database) and I need to 
>> merge these documents in memory to write them back in a database...
>
> You need to give a few more details about what you mean by "I have pdf 
> documents in memory".
> Does that mean that you simply copied the file content to some 
> allocated memory?  Or have
> you opened these pdf files using poppler (using code like in 
> poppler/qt5/demos)?
>
> You need to do the latter to solve your problem.  Open the files using 
> poppler,
> and then copy code that unites them from pdfunite.cc (licences 
> permitting).
>
> Best,
> Oliver
>
Sorry to not be clear : I upload pdf documents (with a c++ cppcms 
server), I get them in some std::istream, I need to manipulate pages of 
these documents, create new  documents from these pages, store these 
documents in bytea postgresql db, extract text from them, retrieve them 
when a user ask to download them...

poppler can make the job, but I do not need and I would like to avoid to 
use files to do all that...

So my question : what is the best strategy ?

I have no license problem, all is open source.

Thank you

PX.