Port _djb_hash to Python 3.

Author: dw

cdblib/_djb_hash.c

@@ -1,6 +1,16 @@
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 
+#if PY_MAJOR_VERSION >= 3
+#   define MOD_RETURN(mod) return mod;
+#   define MODINIT_NAME PyInit__djb_hash
+#   define BUFFERLIKE_FMT "y#"
+#else
+#   define MOD_RETURN(mod) return;
+#   define MODINIT_NAME init_djb_hash
+#   define BUFFERLIKE_FMT "t#"
+#endif
+
 /* Return a Python long instance containing the value of the DJB hash function
  * for the given string or array. */
 static PyObject *
@@ -10,7 +20,7 @@ djb_hash(PyObject *self, PyObject *args)
     unsigned int h = 5381;
     Py_ssize_t len;
 
-    if(! PyArg_ParseTuple(args, "t#", &s, &len))
+    if(! PyArg_ParseTuple(args, BUFFERLIKE_FMT, &s, &len))
         return NULL;
 
     while(len--)
@@ -20,15 +30,34 @@ djb_hash(PyObject *self, PyObject *args)
 }
 
 
-static /*const*/ PyMethodDef methods[] = {
+static /*const*/ PyMethodDef module_methods[] = {
     {"djb_hash", djb_hash, METH_VARARGS,
      "Return the value of DJB's hash function for the given 8-bit string."},
     {NULL, NULL, 0, NULL}
 };
 
+#if PY_MAJOR_VERSION >= 3
+static struct PyModuleDef moduledef = {
+    PyModuleDef_HEAD_INIT,
+    "_djb_hash",
+    NULL,
+    -1,
+    module_methods,
+    NULL,
+    NULL,
+    NULL,
+    NULL
+};
+#endif
 
 PyMODINIT_FUNC
-init_djb_hash(void)
+MODINIT_NAME(void)
 {
-    Py_InitModule("_djb_hash", methods);
+#if PY_MAJOR_VERSION >= 3
+    PyObject *mod = PyModule_Create(&moduledef);
+#else
+    PyObject *mod = Py_InitModule3("_djb_hash", module_methods, "");
+#endif
+
+    MOD_RETURN(mod);
 }

setup.py

@@ -6,7 +6,7 @@
 
 # Opt-in to building the C extensions for Python 2 by setting the
 # ENABLE_DJB_HASH_CEXT environment variable
-if (version_info[0] == 2) and environ.get('ENABLE_DJB_HASH_CEXT'):
+if environ.get('ENABLE_DJB_HASH_CEXT'):
     ext_modules = [
         Extension('cdblib._djb_hash', sources=['cdblib/_djb_hash.c']),
     ]