build.sh

python2 setup.py build

lev.c

#include <Python.h>


int min(int a, int b, int c) {

    int m = a;

    if (b < a) {
        m = b;
    };

    if (c < m) {
        m = c;
    };

    return m;

}

static PyObject *
lev_levenshtein(PyObject *self, PyObject *args)
{
    const char *encoding = "utf-8";

    char *s1, *s2;

    if(!PyArg_ParseTuple(args, "eses", encoding, &s1, encoding, &s2)) {
        return NULL;
    };

    int len_s1 = strlen(s1), len_s2 = strlen(s2);

    int v0[len_s2], v1[len_s2];

    char c1, c2;

    int i, j, x;

    for (x = 0; x <= len_s2; x++) {
        v1[x] = x;
    };

    for (i = 0; i < len_s1; i++) {
        c1 = s1[i];

        for (x = 0; x <= len_s2; x++) {
            v0[x] = v1[x];
        };

        v1[0]++;

        for (j = 1; j <= len_s2; j++) {
            c2 = s2[j - 1];
            if (c1 == c2) {
                v1[j] = v0[j - 1];
            }
            else {
                v1[j] = 1 + min(v0[j - 1], v0[j], v1[j - 1]);
            }
        }
    }

    return Py_BuildValue("i", v1[len_s2]);
};


static PyMethodDef LevMethods[] = {
    {
        "levenshtein", lev_levenshtein, METH_VARARGS,
        "Calculate Levenshtein distance between given strings"
    },
    { NULL, NULL, 0, NULL }
};

PyMODINIT_FUNC
initlev(void) {
    (void) Py_InitModule("lev", LevMethods);
}

setup.py

from distutils.core import setup, Extension

module1 = Extension('lev', sources = ['lev.c'])

setup (name = 'PackageName',
        version = '1.0',
        description = 'This is a demo package',
        ext_modules = [module1])