change byte lengths to use Py_ssize_t

README.rst

@@ -8,7 +8,7 @@ Fast delta encoding in python using xdelta3.
 Requirements
 ------------
 
-* **Python 3.5 or 3.6** - it's 2017, you should be using python 3.6 by now anyway.
+* **Python 3.5 - 3.9** - it's 2021, you should be using python 3.6+ by now anyway.
 * **linux** - compilation only tested on ubuntu, might work on other platform.
 
 Installation

xdelta3/_xdelta3.c

@@ -2,6 +2,7 @@
 
 #include "xdelta3.h"
 #include "xdelta3.c"
+#define PY_SSIZE_T_CLEAN
 #include <Python.h>
 
 static PyObject *NoDeltaFound;
@@ -10,8 +11,9 @@ static PyObject *XDeltaError;
 static PyObject * xdelta3_execute(PyObject *self, PyObject *args)
 {
   uint8_t *input_bytes = NULL, *source_bytes = NULL, *output_buf = NULL;
-  int input_len, source_len, flags, action, result;
-  size_t input_size, source_size, output_alloc, output_size;
+  Py_ssize_t input_len, source_len, output_size;
+  int flags, action, result;
+  size_t input_size, source_size, output_alloc;
 
   if (!PyArg_ParseTuple(args, "y#y#ii", &input_bytes, &input_len, &source_bytes, &source_len, &flags, &action))
     return NULL;