Start wrapping struct inside python class

.gitignore

+*~
\ No newline at end of file

setup.py

+#!/usr/bin/env python3
+
+descr = """
+Wrapper around the SPH cosmological simulation code SWIFT
+"""
+
+from setuptools import setup, find_packages, Extension
+import sys
+from glob import glob
+import numpy
+
+# deal with arguments
+swift_path = None
+swift_arg = "--with-swift"
+if swift_arg in sys.argv:
+    i = sys.argv.find(swift_arg)
+    swift_path = sys.argv[i+1]
+    sys.argv.remove(swift_arg)
+    sys.argv.remove(swift_path)
+
+# python lib dependency
+install_requires=["numpy"]
+
+# link to non pypi dependencies
+dependency_links = []
+
+# C includes
+include = [".", numpy.get_include()]
+
+# C libraries
+lib = ["m"]
+
+#  src files
+c_src = []
+
+# data files
+data_files = []
+
+
+##############
+## C ext
+##############
+
+c_src = glob("src/*.c")
+ext_modules = Extension("pyswiftsim",
+                        c_src,
+                        include_dirs=include,
+                        libraries=lib)
+
+ext_modules = [ext_modules]
+    
+##############
+## data
+##############
+
+data_files = []
+
+##############
+## scripts
+##############
+
+list_scripts = []
+
+##############
+## Setup
+##############
+
+setup(
+    name         = "pyswiftsim",
+    version      = "0.1",
+    author       = "Hausammann Loic",
+    author_email = "loic.hausammann@epfl.ch",
+    description  = descr,
+    license      = "GPLv3",
+    keywords     = "nbody sph simulation hpc",
+    url          = "",
+
+    packages         = find_packages(),
+
+    data_files       = data_files,
+
+    scripts          = list_scripts,
+
+    install_requires = install_requires,
+
+    dependency_links = dependency_links,
+    
+    ext_modules      = ext_modules,
+)

src/pyswiftsim.c

+#define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
+
+#include "units.h"
+
+#include <Python.h>
+#include <math.h>
+#include <numpy/arrayobject.h>
+
+
+/* definition of the method table */      
+      
+static PyMethodDef pyswiftsim_methods[] = {
+
+          {"test",  test, METH_VARARGS,
+           "Test."},	   	         
+	   	   
+          {NULL, NULL, 0, NULL}        /* Sentinel */
+      };      
+      
+      
+
+static struct PyModuleDef pyswiftsim_cmodule = {
+  PyModuleDef_HEAD_INIT,
+  "pyswiftsim",
+  "Wrapper around the SPH cosmological simulation code SWIFT",
+  -1,
+  pyswiftsim_methods
+};
+
+
+PyMODINIT_FUNC PyInit_pyswiftsim(void)
+{
+  PyObject *m;
+
+  Py_Initialize();
+  import_array();
+  m = PyModule_Create(&pyswiftsim_cmodule);
+
+  if (m == NULL)
+    return NULL;
+
+  return m;
+}

src/units.c

+#include "units.h"
+
+#include <Python.h>
+#include <stdlib.h>
+#include <string.h>
+
+PyObject* test(PyObject *self, PyObject *args) {
+  size_t N = sizeof(struct unit_system);
+
+  struct unit_system *us = malloc(N);
+  us->UnitMass_in_cgs = 1.;
+  us->UnitLength_in_cgs = 1.;
+  us->UnitTime_in_cgs = 1.;
+  us->UnitCurrent_in_cgs = 1.;
+  us->UnitTemperature_in_cgs = 1.;
+
+  //char *tmp = malloc(N);
+  //memcpy(tmp, us, N);
+
+  return PyBytes_FromStringAndSize((char*) us, N);
+}

src/units.h

+#ifndef __PYSWIFTSIM_UNITS_H__
+#define __PYSWIFTSIM_UNITS_H__
+
+#include <Python.h>
+
+struct unit_system {
+
+  /*! Conversion factor from grams to internal mass units */
+  double UnitMass_in_cgs;
+
+  /*! Conversion factor from centimeters to internal length unit */
+  double UnitLength_in_cgs;
+
+  /*! Conversion factor from seconds to internal time units */
+  double UnitTime_in_cgs;
+
+  /*! Conversion factor from Ampere to internal current units */
+  double UnitCurrent_in_cgs;
+
+  /*! Conversion factor from Kelvins to internal temperature units. */
+  double UnitTemperature_in_cgs;
+};
+
+
+PyObject* test(PyObject *self, PyObject *args);
+
+#endif // __PYSWIFTSIM_UNITS_H__

test/test_struct.py

+#!/usr/bin/env python3
+import pyswiftsim
+
+print(dir(pyswiftsim))
+print(pyswiftsim.__file__)
+
+t = pyswiftsim.test()
+
+import struct
+
+#print(len(t), t)
+
+print(t)
+data = struct.unpack("ddddd", t)
+
+print(data)