Start on Python interface without SWIG

.gitignore

@@ -15,8 +15,7 @@ inc/blst_aux.h*
 .vscode/
 *.json
 .clang-format
-*bindings/*/_*.so
-*bindings/*/lib*.so
+*bindings/*/*.so
 *bindings/python/ckzg_swig.py
 *bindings/python/ckzg.py
 *bindings/C#/ckzg_swig.cs

min-bindings/python/Makefile

@@ -1,11 +1,17 @@
 INCLUDE_DIRS = .. ../../min-src ../../inc
 INCLUDE_PY = $(shell python -c 'import sysconfig; print(sysconfig.get_config_var("INCLUDEPY"))')
 
+test: tests.py ckzg.so
+	python $<
+
 test_swig: tests_swig.py _ckzg_swig.so
 	python $<
 
 _ckzg_swig.so: c_kzg_4844_wrap.c ../../min-src/c_kzg_4844.o ../../lib/libblst.a
 	clang -O -Wall -shared -fPIC -Wl,-Bsymbolic -I${INCLUDE_PY} ${addprefix -I,${INCLUDE_DIRS}} -o $@ $^
 
+ckzg.so: ckzg.c ../../min-src/c_kzg_4844.o ../../lib/libblst.a
+	clang -O -Wall -shared -fPIC -Wl,-Bsymbolic -I${INCLUDE_PY} ${addprefix -I,${INCLUDE_DIRS}} -o $@ $^
+
 c_kzg_4844_wrap.c ckzg_swig.py: ../c_kzg_4844.swg
 	swig -DSWIGWORDSIZE64 -O -Wall -python -outcurrentdir $<

min-bindings/python/ckzg.c

@@ -0,0 +1,56 @@
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include "c_kzg_4844.h"
+
+static void free_capsule(PyObject *c) {
+  free(PyCapsule_GetPointer(c, PyCapsule_GetName(c)));
+}
+
+static PyObject* bytes_to_bls_field_wrap(PyObject *self, PyObject *args) {
+  PyBytesObject *pybytes;
+
+  if (!PyArg_ParseTuple(args, "S", &pybytes) ||
+      PyBytes_Size((PyObject*)pybytes) != 32)
+    return PyErr_Format(PyExc_ValueError, "expected 32 bytes");
+
+  BLSFieldElement *out = (BLSFieldElement*)malloc(sizeof(BLSFieldElement));
+
+  if (out == NULL) return PyErr_NoMemory();
+
+  bytes_to_bls_field(out, (const uint8_t*)PyBytes_AsString((PyObject*)pybytes));
+
+  return PyCapsule_New(out, "BLSFieldElement", free_capsule);
+}
+
+static PyObject* uint64s_from_BLSFieldElement_wrap(PyObject *self, PyObject *args) {
+  PyObject *c;
+  if (!PyArg_UnpackTuple(args, "uint64s_from_BLSFieldElement", 1, 1, &c) ||
+      !PyCapsule_IsValid(c, "BLSFieldElement"))
+    return PyErr_Format(PyExc_ValueError, "expected a BLSFieldElement capsule");
+  uint64_t out[4];
+  uint64s_from_BLSFieldElement(out, PyCapsule_GetPointer(c, PyCapsule_GetName(c)));
+  return PyTuple_Pack(4,
+      PyLong_FromUnsignedLong(out[0]),
+      PyLong_FromUnsignedLong(out[1]),
+      PyLong_FromUnsignedLong(out[2]),
+      PyLong_FromUnsignedLong(out[3]));
+}
+
+static PyMethodDef ckzgmethods[] = {
+  {"uint64s_from_BLSFieldElement", uint64s_from_BLSFieldElement_wrap, METH_VARARGS, "Convert a field element to a 4-tuple of uint64s"},
+  {"bytes_to_bls_field", bytes_to_bls_field_wrap, METH_VARARGS, "Convert 32 bytes to a field element"},
+  {NULL, NULL, 0, NULL}
+};
+
+static struct PyModuleDef ckzg = {
+  PyModuleDef_HEAD_INIT,
+  "ckzg",
+  NULL,
+  -1,
+  ckzgmethods
+};
+
+PyMODINIT_FUNC PyInit_ckzg(void)
+{
+    return PyModule_Create(&ckzg);
+}

min-bindings/python/tests.py

@@ -0,0 +1,25 @@
+import atexit
+import ckzg
+import random
+import ssz
+
+def int_from_fr(fr):
+    digits = ckzg.uint64s_from_BLSFieldElement(fr)
+    res, mult = 0, 1
+    for x in digits:
+        res += mult * x
+        mult *= 2**64
+    return res
+
+# Simple test of bytes_to_bls_field
+
+bs = (329).to_bytes(32, "little")
+fr = ckzg.bytes_to_bls_field(bs)
+assert int_from_fr(fr) == 329
+
+print('Tests passed')
+
+def cleanup():
+    pass
+
+atexit.register(cleanup)