Openstack RDO && KVM Hypervisor: Working on Basic Python C Extensions on Fedora Linux 34 (2)

Relatively complicated sample based on

https://stackabuse.com/enhancing-python-with-custom-c-extensions

with minor refactoring just to make things clear

(.env) [boris@sever33fedora enhancePython]$ cat demo.h

unsigned long cfactorial_sum(char num_chars[]);

unsigned long ifactorial_sum(long nums[], int size);

unsigned long factorial(long n);

(.env) [boris@sever33fedora enhancePython]$ cat demolib.c

#include <stdio.h>

#include "demo.h"

unsigned long cfactorial_sum(char num_chars[]) {

unsigned long fact_num;

unsigned long sum = 0;

for (int i = 0; num_chars[i]; i++) {

int ith_num = num_chars[i] - '0';

fact_num = factorial(ith_num);

sum = sum + fact_num;

}

return sum;

}

unsigned long ifactorial_sum(long nums[], int size) {

unsigned long fact_num;

unsigned long sum = 0;

for (int i = 0; i < size; i++) {

fact_num = factorial(nums[i]);

sum += fact_num;

}

return sum;

}

unsigned long factorial(long n) {

if (n == 0)

return 1;

return (unsigned)n * factorial(n-1);

}

(.env) [boris@sever33fedora enhancePython]$ cat demo.c

#include <Python.h>

#include <stdio.h>

#include "demo.h"

Just to suppress warnings, which don't affect runtime phase

#pragma GCC diagnostic ignored "-Wincompatible-pointer-types"

// wrapper function for cfactorial_sum

static PyObject *DemoLib_cFactorialSum(PyObject *self, PyObject *args) {

char *char_nums;

if (!PyArg_ParseTuple(args, "s", &char_nums)) {

return NULL;

}

unsigned long fact_sum;

fact_sum = cfactorial_sum(char_nums);

return Py_BuildValue("i", fact_sum);

}

// wrapper function for ifactorial_sum

static PyObject *DemoLib_iFactorialSum(PyObject *self, PyObject *args) {

I believe this declaration is a cause of several

"-Wincompatible-pointer-types" warnings,

which are easy to see commenting #pragma GCC

directive out

PyObject *lst;

if (!PyArg_ParseTuple(args, "O", &lst)) {

return NULL;

}

int n = PyObject_Length(lst);

if (n < 0) {

return NULL;

}

long nums[n];

for (int i = 0; i < n; i++) {

PyLongObject *item = PyList_GetItem(lst, i);

/* long num = PyLong_AsLong(item); */

nums[i] = PyLong_AsLong(item);

}

unsigned long fact_sum;

fact_sum = ifactorial_sum(nums, n);

return Py_BuildValue("i", fact_sum);

}

// module's function table

static PyMethodDef DemoLib_FunctionsTable[] = {

{

"sfactorial_sum", // name exposed to Python

DemoLib_cFactorialSum, // C wrapper function

METH_VARARGS, // received variable args (but really just 1)

"Calculates factorial sum from digits in string of numbers" // documentation

}, {

"ifactorial_sum", // name exposed to Python

DemoLib_iFactorialSum, // C wrapper function

METH_VARARGS, // received variable args (but really just 1)

"Calculates factorial sum from list of ints" // documentation

}, {

NULL, NULL, 0, NULL

}

};

// modules definition

static struct PyModuleDef DemoLib_Module = {

PyModuleDef_HEAD_INIT,

"demo", // name of module exposed to Python

"Demo Python wrapper for custom C extension library.", // module documentation

-1,

DemoLib_FunctionsTable

};

PyMODINIT_FUNC PyInit_demo(void) {

return PyModule_Create(&DemoLib_Module);

}

(.env) [boris@sever33fedora enhancePython]$ cat setup.py

from setuptools import Extension, setup

module = Extension("demo",

sources=[

'demo.c',

'demolib.c'

])

setup(name='demo',

version='1.0',

description='Python wrapper for custom C extension',

ext_modules=[module])

(.env) [boris@sever33fedora enhancePython]$ cat MyProg.py
import demo
print("Calling sfactorial_sum(\"1234567\") gives \n",demo.sfactorial_sum("1234567"))
print("Calling ifactorial_sum([1,2,3,4,5,6,7]) gives \n",\
demo.ifactorial_sum([1,2,3,4,5,6,7]))

(.env) [boris@sever33fedora enhancePython]$ python setup.py

install

running install

running bdist_egg

running egg_info

creating demo.egg-info

writing demo.egg-info/PKG-INFO

writing dependency_links to demo.egg-info/dependency_links.txt

writing top-level names to demo.egg-info/top_level.txt

writing manifest file 'demo.egg-info/SOURCES.txt'

reading manifest file 'demo.egg-info/SOURCES.txt'

writing manifest file 'demo.egg-info/SOURCES.txt'

installing library code to build/bdist.linux-x86_64/egg

running install_lib

running build_ext

building 'demo' extension

creating build

creating build/temp.linux-x86_64-3.9

gcc -pthread -Wno-unused-result -Wsign-compare -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -O2 -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fstack-protector-strong -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -D_GNU_SOURCE -fPIC -fwrapv -O2 -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fstack-protector-strong -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -D_GNU_SOURCE -fPIC -fwrapv -O2 -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fstack-protector-strong -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -D_GNU_SOURCE -fPIC -fwrapv -fPIC -I/home/boris/enhancePython/.env/include -I/usr/include/python3.9 -c demo.c -o build/temp.linux-x86_64-3.9/demo.o

creating build/lib.linux-x86_64-3.9

gcc -pthread -shared -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -g -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -g build/temp.linux-x86_64-3.9/demo.o build/temp.linux-x86_64-3.9/demolib.o -L/usr/lib64 -o build/lib.linux-x86_64-3.9/demo.cpython-39-x86_64-linux-gnu.so

creating build/bdist.linux-x86_64

creating build/bdist.linux-x86_64/egg

copying build/lib.linux-x86_64-3.9/demo.cpython-39-x86_64-linux-gnu.so -> build/bdist.linux-x86_64/egg

creating stub loader for demo.cpython-39-x86_64-linux-gnu.so

byte-compiling build/bdist.linux-x86_64/egg/demo.py to demo.cpython-39.pyc

creating build/bdist.linux-x86_64/egg/EGG-INFO

copying demo.egg-info/PKG-INFO -> build/bdist.linux-x86_64/egg/EGG-INFO

copying demo.egg-info/SOURCES.txt -> build/bdist.linux-x86_64/egg/EGG-INFO

copying demo.egg-info/dependency_links.txt -> build/bdist.linux-x86_64/egg/EGG-INFO

copying demo.egg-info/top_level.txt -> build/bdist.linux-x86_64/egg/EGG-INFO

writing build/bdist.linux-x86_64/egg/EGG-INFO/native_libs.txt

zip_safe flag not set; analyzing archive contents...

__pycache__.demo.cpython-39: module references __file__

creating dist

creating 'dist/demo-1.0-py3.9-linux-x86_64.egg' and adding 'build/bdist.linux-x86_64/egg' to it

removing 'build/bdist.linux-x86_64/egg' (and everything under it)

Processing demo-1.0-py3.9-linux-x86_64.egg

removing '/home/boris/enhancePython/.env/lib/python3.9/site-packages/demo-1.0-py3.9-linux-x86_64.egg' (and everything under it)

creating /home/boris/enhancePython/.env/lib/python3.9/site-packages/demo-1.0-py3.9-linux-x86_64.egg

Extracting demo-1.0-py3.9-linux-x86_64.egg to /home/boris/enhancePython/.env/lib/python3.9/site-packages

demo 1.0 is already the active version in easy-install.pth

Installed /home/boris/enhancePython/.env/lib/python3.9/site-packages/demo-1.0-py3.9-linux-x86_64.egg

Processing dependencies for demo==1.0

Finished processing dependencies for demo==1.0

(.env) [boris@sever33fedora enhancePython]$ python MyProg.py

Calling sfactorial_sum("1234567") gives

5913

Calling ifactorial_sum([1,2,3,4,5,6,7]) gives

5913

Openstack RDO && KVM Hypervisor

Monday, June 21, 2021

Working on Basic Python C Extensions on Fedora Linux 34 (2)

1 comment:

Blog Archive