how to call this dll in python

[Shark]

I have a windows dll1.dll with a export function:

int f1(char filename,char **buf,int *bufLen)
{
int len;
//got the length of file anyway,such as 100
len = 100;//len = getLen(filename);
*buf = (char*)calloc(100);
*bufLen = len;
return 0;
}

then how can I call the f1 function with python.
thanks for your response.