string holder test

src/polluck_blockchain/placeholder.py

@@ -1 +1,45 @@
-"""placeholder module for compilation"""
+"""placeholder module for compilation"""
+
+import typing as t
+
+import cython
+from cython.cimports.cpython.ref import Py_INCREF
+
+
+@cython.cclass
+class StringHolder:
+    _data = cython.declare(cython.p_char, visibility="private")
+    _length = cython.declare(cython.Py_ssize_t, visibility="readonly")
+    _py_cache = cython.declare(object, visibility="private")
+
+    def __cinit__(self, data: str) -> None:
+        """accepting Python str
+
+        Parameters
+        ----------
+        data : str
+            _description_
+        """
+        if not isinstance(data, str):
+            raise TypeError("Data not 'str'")
+
+        tmp = data.encode("utf-8")
+        Py_INCREF(tmp)
+        self._data = tmp
+        self._length = len(tmp)
+        self._py_cache = None
+
+    @cython.cfunc
+    def _bytes_to_str(self) -> str:
+        tmp = t.cast(bytes, self._data[: self._length])
+        return tmp.decode("utf-8")
+
+    @property
+    def py_string(self) -> str:
+        if self._py_cache is None:
+            self._py_cache = self._bytes_to_str()
+        return t.cast(str, self._py_cache)
+
+    @property
+    def py_bytes(self) -> bytes:
+        return t.cast(bytes, self._data[: self._length])