Issue #4258: Use 30-bit digits for Python longs, on 64-bit platforms.
Backport of r70459.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 9bd6378..e4e8859 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -6,6 +6,7 @@
#include "Python.h"
#include "longintrepr.h"
+#include "structseq.h"
#include <ctype.h>
#include <stddef.h>
@@ -3646,3 +3647,51 @@
long_new, /* tp_new */
PyObject_Del, /* tp_free */
};
+
+static PyTypeObject Long_InfoType;
+
+PyDoc_STRVAR(long_info__doc__,
+"sys.long_info\n\
+\n\
+A struct sequence that holds information about Python's\n\
+internal representation of integers. The attributes are read only.");
+
+static PyStructSequence_Field long_info_fields[] = {
+ {"bits_per_digit", "size of a digit in bits"},
+ {"sizeof_digit", "size in bytes of the C type used to "
+ "represent a digit"},
+ {NULL, NULL}
+};
+
+static PyStructSequence_Desc long_info_desc = {
+ "sys.long_info", /* name */
+ long_info__doc__, /* doc */
+ long_info_fields, /* fields */
+ 2 /* number of fields */
+};
+
+PyObject *
+PyLong_GetInfo(void)
+{
+ PyObject* long_info;
+ int field = 0;
+ long_info = PyStructSequence_New(&Long_InfoType);
+ if (long_info == NULL)
+ return NULL;
+ PyStructSequence_SET_ITEM(long_info, field++, PyLong_FromLong(PyLong_SHIFT));
+ PyStructSequence_SET_ITEM(long_info, field++, PyLong_FromLong(sizeof(digit)));
+ if (PyErr_Occurred()) {
+ Py_CLEAR(long_info);
+ return NULL;
+ }
+ return long_info;
+}
+
+int
+_PyLong_Init(void)
+{
+ /* initialize long_info */
+ if (Long_InfoType.tp_name == 0)
+ PyStructSequence_InitType(&Long_InfoType, &long_info_desc);
+ return 1;
+}