python 调用C程序，简单的C扩展模块

python 调用C程序，简单的C扩展模块

C语言源代码

• C语言源代码，sample.h

/*
 * sample.h
 *
 *  Created on: 2022年12月29日
 *      Author: xzlAwin
 */
extern int gcd(int x, int y);
extern int in_mandel(double x0, double y0, int n);
extern int divide(int a, int b, int *remainder);
extern double avg(double *a, int n);

typedef struct Point {
	double x,y;
} Point;

extern double distance(Point *p1, Point *p2);

• C语言源代码，sample.c

/*
 * sample.c
 *
 *  Created on: 2022年12月29日
 *      Author: xzlAwin
 */

#include<math.h>

/* Compute the greatest common divisor */
int gcd(int x, int y) {
	int g = y;
	while(x > 0) {
		g = x;
		x = y % x;
		y = g;
	}
	return g;
}

/* Test if (x0,y0) is in the Mandelbrot set or not */
int in_mandel(double x0, double y0, int n) {
	double x=0,y=0,xtemp;
	while (n > 0) {
		xtemp = x*x - y*y +x0;
		y = 2*x*y + y0;
		x = xtemp;
		n -= 1;
		if(x*x + y*y > 4) return 0;
	}
	return 1;
}

/* Divide two numbers */
int divide(int a, int b, int *remainder) {
	int quot = a / b;
	*remainder = a % b;
	return quot;
}

/* Average values in an array */
double avg(double *a, int n) {
	int i;
	double total = 0.0;
	for (i = 0; i < n; i++) {
		total += a[i];
	}
	return total / n;
}

/* A C data structure */
typedef struct Point {
	double x,y;
} Point;

/* Function involving a C data structure */
double distance(Point *p1, Point *p2) {
	return hypot(p1->x - p2->x, p1->y - p2->y);
}

• C语言源代码，pysample.c

/*
 * pysample.c
 *
 *  Created on: 2022年12月29日
 *      Author: xzlAwin
 */

#include "Python.h"
#include "sample.h"

/* int gcd(int, int) */
static PyObject *py_gcd(PyObject *self, PyObject *args) {
  int x, y, result;

  if (!PyArg_ParseTuple(args,"ii", &x, &y)) {
    return NULL;
  }
  result = gcd(x,y);
  return Py_BuildValue("i", result);
}

/* int in_mandel(double, double, int) */
static PyObject *py_in_mandel(PyObject *self, PyObject *args) {
  double x0, y0;
  int n;
  int result;

  if (!PyArg_ParseTuple(args, "ddi", &x0, &y0, &n)) {
    return NULL;
  }
  result = in_mandel(x0,y0,n);
  return Py_BuildValue("i", result);
}

/* int divide(int, int, int *) */
static PyObject *py_divide(PyObject *self, PyObject *args) {
  int a, b, quotient, remainder;
  if (!PyArg_ParseTuple(args, "ii", &a, &b)) {
    return NULL;
  }
  quotient = divide(a,b, &remainder);
  return Py_BuildValue("(ii)", quotient, remainder);
}

/* Module method table */
static PyMethodDef SampleMethods[] = {
  {"gcd",  py_gcd, METH_VARARGS, "Greatest common divisor"},
  {"in_mandel", py_in_mandel, METH_VARARGS, "Mandelbrot test"},
  {"divide", py_divide, METH_VARARGS, "Integer division"},
  { NULL, NULL, 0, NULL}
};

/* Module structure */
static struct PyModuleDef samplemodule = {
  PyModuleDef_HEAD_INIT,
  "sample",           /* name of module */
  "A sample module",  /* Doc string (may be NULL) */
  -1,                 /* Size of per-interpreter state or -1 */
  SampleMethods       /* Method table */
};

/* Module initialization function */
PyMODINIT_FUNC
PyInit_sample(void) {
  return PyModule_Create(&samplemodule);
}

编译pyc库

• python构建源代码，setup.py

from distutils.core import setup, Extension

setup(name="sample", 
      ext_modules=[
        Extension("sample",
                  ["sample.c","pysample.c"],
                  include_dirs=[".."]
                  )
        ]
)

• python命令行，编译pyc库，编译成功生成 sample.cp37-win_amd64.pyd

python3 setup.py build_ext --inplace

测试

• python测试源代码，main.py

import sample

print(sample.gcd(35,42))
print(sample.in_mandel(0,0,500))
print(sample.in_mandel(2.0,1.0,500))
print(sample.divide(42,8))

• python命令行，运行测试代码

python3 main.py

运行成功显示

7
1
0
(5, 2)