Issue #16590: remove obsolete compatibility code from the _json module.

Patch by Serhiy Storchaka.

Modules/_json.c

@@ -2,20 +2,6 @@
 #include "structmember.h"
 #include "accu.h"
 
-#if PY_VERSION_HEX < 0x02060000 && !defined(Py_TYPE)
-#define Py_TYPE(ob)     (((PyObject*)(ob))->ob_type)
-#endif
-#if PY_VERSION_HEX < 0x02050000 && !defined(PY_SSIZE_T_MIN)
-typedef int Py_ssize_t;
-#define PY_SSIZE_T_MAX INT_MAX
-#define PY_SSIZE_T_MIN INT_MIN
-#define PyInt_FromSsize_t PyInt_FromLong
-#define PyInt_AsSsize_t PyInt_AsLong
-#endif
-#ifndef Py_IS_FINITE
-#define Py_IS_FINITE(X) (!Py_IS_INFINITY(X) && !Py_IS_NAN(X))
-#endif
-
 #ifdef __GNUC__
 #define UNUSED __attribute__((__unused__))
 #else
@@ -129,33 +115,12 @@ static void
 raise_errmsg(char *msg, PyObject *s, Py_ssize_t end);
 static PyObject *
 encoder_encode_string(PyEncoderObject *s, PyObject *obj);
-static int
-_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr);
-static PyObject *
-_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr);
 static PyObject *
 encoder_encode_float(PyEncoderObject *s, PyObject *obj);
 
 #define S_CHAR(c) (c >= ' ' && c <= '~' && c != '\\' && c != '"')
 #define IS_WHITESPACE(c) (((c) == ' ') || ((c) == '\t') || ((c) == '\n') || ((c) == '\r'))
 
-static int
-_convertPyInt_AsSsize_t(PyObject *o, Py_ssize_t *size_ptr)
-{
-    /* PyObject to Py_ssize_t converter */
-    *size_ptr = PyLong_AsSsize_t(o);
-    if (*size_ptr == -1 && PyErr_Occurred())
-        return 0;
-    return 1;
-}
-
-static PyObject *
-_convertPyInt_FromSsize_t(Py_ssize_t *size_ptr)
-{
-    /* Py_ssize_t to PyObject converter */
-    return PyLong_FromSsize_t(*size_ptr);
-}
-
 static Py_ssize_t
 ascii_escape_unichar(Py_UCS4 c, unsigned char *output, Py_ssize_t chars)
 {
@@ -265,7 +230,7 @@ raise_errmsg(char *msg, PyObject *s, Py_ssize_t end)
         if (errmsg_fn == NULL)
             return;
     }
-    pymsg = PyObject_CallFunction(errmsg_fn, "(zOO&)", msg, s, _convertPyInt_FromSsize_t, &end);
+    pymsg = PyObject_CallFunction(errmsg_fn, "(zOn)", msg, s, end);
     if (pymsg) {
         PyErr_SetObject(PyExc_ValueError, pymsg);
         Py_DECREF(pymsg);
@@ -524,7 +489,7 @@ py_scanstring(PyObject* self UNUSED, PyObject *args)
     Py_ssize_t end;
     Py_ssize_t next_end = -1;
     int strict = 1;
-    if (!PyArg_ParseTuple(args, "OO&|i:scanstring", &pystr, _convertPyInt_AsSsize_t, &end, &strict)) {
+    if (!PyArg_ParseTuple(args, "On|i:scanstring", &pystr, &end, &strict)) {
         return NULL;
     }
     if (PyUnicode_Check(pystr)) {
@@ -1087,7 +1052,7 @@ scanner_call(PyObject *self, PyObject *args, PyObject *kwds)
     PyScannerObject *s;
     assert(PyScanner_Check(self));
     s = (PyScannerObject *)self;
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO&:scan_once", kwlist, &pystr, _convertPyInt_AsSsize_t, &idx))
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "On:scan_once", kwlist, &pystr, &idx))
         return NULL;
 
     if (PyUnicode_Check(pystr)) {
@@ -1288,8 +1253,8 @@ encoder_call(PyObject *self, PyObject *args, PyObject *kwds)
 
     assert(PyEncoder_Check(self));
     s = (PyEncoderObject *)self;
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO&:_iterencode", kwlist,
-        &obj, _convertPyInt_AsSsize_t, &indent_level))
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "On:_iterencode", kwlist,
+        &obj, &indent_level))
         return NULL;
     if (_PyAccu_Init(&acc))
         return NULL;