http://amazingjxq.com/2012/01/09/python%E8%B0%83%E7%94%A8c%E5%87%BD%E6%95%B0/
>>>cd /home/jxq/code/
然后在python里面用ctypes加载刚才的动态库。argtypes和restype分别对应函数的参数和返回值的类型。这样就可以直接调用了。
>>> bob_hash = CDLL('/home/jxq/code/bob_hash.so')
>>> hash_string = bob_hash.hash_string
>>> hash_string.argtypes = [c_void_p]
>>> hash_string.restype = c_int
>>> hash_string('123')
代码：
#include <stdio.h>
#include <string.h>
#define mix(a,b,c)
{
a -= b; a -= c; a ^= (c >> 13);
b -= c; b -= a; b ^= (a << 8);
c -= a; c -= b; c ^= (b >> 13);
a -= b; a -= c; a ^= (c >> 12);
b -= c; b -= a; b ^= (a << 16);
c -= a; c -= b; c ^= (b >> 5);
a -= b; a -= c; a ^= (c >> 3);
b -= c; b -= a; b ^= (a << 10);
c -= a; c -= b; c ^= (b >> 15);
}
unsigned int bob_hash(void *val, unsigned int length)
{
char *k = (char *)val;
unsigned long a,b,c,len;
/* Set up the internal state */
len = length;
a = b = c = 0x9e3779b9; /* the golden ratio; an arbitrary value */
/* Handle most of the key */
while (len >= 12)
{
a += (k[0] +((unsigned long)k[1] << 8) +((unsigned long)k[2] << 16) +((unsigned long)k[3] << 24));
b += (k[4] +((unsigned long)k[5] << 8) +((unsigned long)k[6] << 16) +((unsigned long)k[7] << 24));
c += (k[8] +((unsigned long)k[9] << 8) +((unsigned long)k[10]<< 16)+((unsigned long)k[11] << 24));
mix(a,b,c);
k += 12; len -= 12;
}
/* Handle the last 11 bytes */
c += length;
switch(len) /* all the case statements fall through */
{
case 11: c+=((unsigned long)k[10] << 24);
case 10: c+=((unsigned long)k[9] << 16);
case 9 : c+=((unsigned long)k[8] << 8);
/* the first byte of c is reserved for the length */
case 8 : b+=((unsigned long)k[7] << 24);
case 7 : b+=((unsigned long)k[6] << 16);
case 6 : b+=((unsigned long)k[5] << 8);
case 5 : b+=k[4];
case 4 : a+=((unsigned long)k[3] << 24);
case 3 : a+=((unsigned long)k[2] << 16);
case 2 : a+=((unsigned long)k[1] << 8);
case 1 : a+=k[0];
}
mix(a,b,c);
return c;
}
int hash_string(void *tmpstr)
{
int hash = (int)bob_hash(tmpstr, strlen(tmpstr));
if(hash < 0)
{
hash = -hash;
}
return (int)(hash % 200);
}
)
)
