cpython/Tools/perfecthash/perfhash.c

73 lines
1.5 KiB
C

#include <Python.h>
static PyObject * hashFunction(PyObject *self, PyObject *args, PyObject *kw)
{
PyStringObject *a;
register int len;
register unsigned char *p;
register long x;
long lSeed;
unsigned long cchSeed;
if (!PyArg_ParseTuple(args, "iiO:hash", &lSeed, &cchSeed, &a))
return NULL;
if (!PyString_Check(a))
{
PyErr_SetString(PyExc_TypeError, "arg 3 needs to be a string");
return NULL;
}
len = a->ob_size;
p = (unsigned char *) a->ob_sval;
x = lSeed;
while (--len >= 0)
x = (1000003*x) ^ *p++;
x ^= a->ob_size + cchSeed;
if (x == -1)
x = -2;
return PyInt_FromLong(x);
}
static PyObject * calcSeed(PyObject *self, PyObject *args, PyObject *kw)
{
PyStringObject *a;
register int len;
register unsigned char *p;
register long x;
if (!PyString_Check(args))
{
PyErr_SetString(PyExc_TypeError, "arg 1 expected a string, but didn't get it.");
return NULL;
}
a = (PyStringObject *)args;
len = a->ob_size;
p = (unsigned char *) a->ob_sval;
x = *p << 7;
while (--len >= 0)
x = (1000003*x) ^ *p++;
return PyInt_FromLong(x);
}
static struct PyMethodDef hashMethods[] = {
{ "calcSeed", calcSeed, 0, NULL },
{ "hash", hashFunction, 0, NULL },
{ NULL, NULL, 0, NULL } /* sentinel */
};
#ifdef _MSC_VER
_declspec(dllexport)
#endif
void initperfhash()
{
PyObject *m;
m = Py_InitModule4("perfhash", hashMethods,
NULL, NULL, PYTHON_API_VERSION);
if ( m == NULL )
Py_FatalError("can't initialize module hashModule");
}