c写python模块扩展
python版本在我之前一篇blog里http://my.oschina.net/1123581321/blog/220751
代码结构
xorcrypt-0.2
\setup.py
\xorcrypt2.c
\README
setup.py
#!/usr/bin/python
from distutils.core import setup, Extension
__version__ = "0.2"
macros = [('MODULE_VERSION', '"%s"' % __version__)]
setup(name = "xorcrypt2",
version = __version__,
author = "fk",
author_email = "[email protected]",
url = "",
download_url = "",
description = "XOR encrypt/decrypt for Python",
long_description = open('README').read(),
license = "LGPL",
platforms = ["Platform Independent"],
classifiers = [
"Development Status :: 5 - Production/Stable",
"Intended Audience :: Developers",
"License :: OSI Approved :: GNU Library or Lesser General Public License (LGPL)",
"Operating System :: OS Independent",
"Programming Language :: Python",
"Topic :: Software Development :: Libraries :: Python Modules"
],
ext_modules = [
Extension(name='xorcrypt2', sources=['xorcrypt2.c'], define_macros=macros)
]
)
xorcrypt2.c
#include <Python.h>
#include <stdio.h>
static PyObject* xor_crypt(PyObject* self, PyObject* args)
{
char* s;
unsigned int key = 0;
unsigned int M1 = 0;
unsigned int IA1 = 0;
unsigned int IC1 = 0;
unsigned int size;
PyObject* v;
char *p;
unsigned int i = 0;
unsigned char c;
// 解析参数 s#表示字符串和它的长度, |后的表示可选参数, I表示unsigned int
if(!PyArg_ParseTuple(args, "s#|IIII", &s, &size, &key, &M1, &IA1, &IC1))
return NULL;
if(key == 0)
key = 1;
if(M1 == 0)
M1 = 1 << 19;
if(IA1 == 0)
IA1 = 2 << 20;
if(IC1 == 0)
IC1 = 3<< 21;
// v是python的空字符串, 长度为size
v = PyString_FromStringAndSize((char*)NULL, size);
if(v == NULL)
return NULL;
// p是把python的字符串v转换为c的字符串, 对p进行操作也会影响v
p = PyString_AS_STRING(v);
for (i = 0; i < size; i++) {
c = (unsigned char)s[i];
key = IA1 * (key % M1) + IC1;
*p = c ^ (unsigned char)((key >> 20)&0xff);
p++;
}
return v;
}
// 方法列表, 要传到初始化函数里
static PyMethodDef xorcrypt2_methods[] = {
// 对应python的模块名.方法名 | 对应的c函数 | METH_VARARGS用来告诉python, crypt是用c实现的 | 函数说明
{"crypt", (PyCFunction)xor_crypt, METH_VARARGS, PyDoc_STR("encrypt/decrypt(string) -> generate the string.")},
{NULL, NULL} // sentinel
};
PyDoc_STRVAR(module_doc, "XOR encrypt/decrypt module.");
/* 当初始化模块时, 这个函数自动被调用, 函数名要固定为 <init+模块名> */
PyMODINIT_FUNC initxorcrypt2(void)
{
PyObject *m;
m = Py_InitModule3("xorcrypt2", xorcrypt2_methods, module_doc);
if (m == NULL)
return;
PyModule_AddStringConstant(m, "__version__", "0.2");
}
安装(编译)
python setup.py install(build)
套着写就行了
import xorcrypt2
print xorcrypt2.crypt("abc", 2)
# 'kde'
print xorcrypt2.crypt("kde", 2)
# 'abc'
---
测试发现这个c版本的速度是python版本的42倍! 很吃惊