Request to add pylzfse to Pythonista

TechnoExplorer

Hi

I was wondering whether pylzfse could be added to pythonista as I’m currently working on an image decompression project.

Also I can’t just copy the code over as its c code.

Thanks

JonB

Apple provides the compression library, which includes lzsfe. You can implement your own wrapper to these functions using ctypes.

TechnoExplorer

I wanted to try and build it as a c extention for pythonista. I have already suceeded in building it for macOS, but having trouble building it for pythonista. I've tried both pip and python setup.py build, but they both fail. In truth, there are no errors, but it doesn’t show up when I try to import it.

This is what I get when I try to install it

[pylzfse]$ python setup.py install
running install
running build
running build_ext
building 'lzfse' extension
xcrun --sdk iphonesimulator clang -arch x86_64 --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator9.3.sdk -miphoneos-version-min=7.0 -fno-strict-aliasing -OPT:Olimit=0 -g -O2 -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -Ilzfse/src -I/var/containers/Bundle/Application/6419CEB5-AE35-4A82-8ED9-EC7744B0314A/Pythonista3.app/Frameworks/Py2Kit.framework/pylib/include/python2.7 -c lzfse/src/lzvn_decode_base.c -o build/temp.darwin-18.2.0-iPad5,3-2.7/lzfse/src/lzvn_decode_base.o -std=c99

JonB

You cannot build a c extension. However you could build a wrapper using ctypes to call iOS built in libraries. Or also could use cffi.

TechnoExplorer

If you can’t build c extensions, then why is there a page dedicated to it? - http://omz-software.com/pythonista/docs/extending/building.html

JonB

Everything below the line is just a copy of the police standard library docs.
... However iOS kernel restrictions prevent loading unsigned executable code.
Also multiprocessing, and some other standard python bits are unsupported.

But again, ctypes is provided, and you can totally write a few line wrapper to each compression library methods.

JonB

Sorry, let me clarify -- you cannot use c extenaions in the app. But you could use the XCode template to build your own app, in which case you can (since you would be using your developer id to sign the files)

TechnoExplorer

Ah. I see. The thing is that I need to be able to run this in pythonista on my iPad for ideal portability between different OS’s. Idk whether I could cffi on my Mac for this and then move it over to pythonista. Bottom line is that I need to somehow get this code running in pythonista because I don’t exactly want to do a complete port of it to the python programming language.

JonB

try :
    import pylzsfe
except ImportError:
    import pylzsfe_wrapper as pylzsfe

Handles the compatibility issues. As far as I can tell, pylzsfe offers two methods -- compress and decompress, so should be straightforward to implement the ctypes wrappers and whatever wrappers to simulate that pylzsfe interface. That's sort of the only real option you have, certainly in the short term.