Marc-Andre Lemburg <mal@lemburg.com>:

Utility extension module needed by perfect_hash.py

By Bill Tutt.

Tools/perfecthash/perfhash.c

@@ -0,0 +1,72 @@
+#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");
+}