Faster path for PyLong_FromLongLong, using PyLong_FromLong algorithm

diff --git a/Objects/longobject.c b/Objects/longobject.c
index 9b1a0b977726dfbebf783fb0ceb65615dff8a70b..cca7b38378c3996f622883d6cf8486e57351025f 100644 (file)
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -844,11 +844,36 @@ PyLong_AsVoidPtr(PyObject *vv)
 PyObject *
 PyLong_FromLongLong(PY_LONG_LONG ival)
 {
-       PY_LONG_LONG bytes = ival;
-       int one = 1;
-       return _PyLong_FromByteArray(
-                       (unsigned char *)&bytes,
-                       SIZEOF_LONG_LONG, IS_LITTLE_ENDIAN, 1);
+       PyLongObject *v;
+       unsigned PY_LONG_LONG t;  /* unsigned so >> doesn't propagate sign bit */
+       int ndigits = 0;
+       int negative = 0;
+
+       if (ival < 0) {
+               ival = -ival;
+               negative = 1;
+       }
+
+       /* Count the number of Python digits.
+          We used to pick 5 ("big enough for anything"), but that's a
+          waste of time and space given that 5*15 = 75 bits are rarely
+          needed. */
+       t = (unsigned PY_LONG_LONG)ival;
+       while (t) {
+               ++ndigits;
+               t >>= SHIFT;
+       }
+       v = _PyLong_New(ndigits);
+       if (v != NULL) {
+               digit *p = v->ob_digit;
+               v->ob_size = negative ? -ndigits : ndigits;
+               t = (unsigned PY_LONG_LONG)ival;
+               while (t) {
+                       *p++ = (digit)(t & MASK);
+                       t >>= SHIFT;
+               }
+       }
+       return (PyObject *)v;
 }
 
 /* Create a new long int object from a C unsigned PY_LONG_LONG int. */
@@ -856,11 +881,26 @@ PyLong_FromLongLong(PY_LONG_LONG ival)
 PyObject *
 PyLong_FromUnsignedLongLong(unsigned PY_LONG_LONG ival)
 {
-       unsigned PY_LONG_LONG bytes = ival;
-       int one = 1;
-       return _PyLong_FromByteArray(
-                       (unsigned char *)&bytes,
-                       SIZEOF_LONG_LONG, IS_LITTLE_ENDIAN, 0);
+       PyLongObject *v;
+       unsigned PY_LONG_LONG t;
+       int ndigits = 0;
+
+       /* Count the number of Python digits. */
+       t = (unsigned PY_LONG_LONG)ival;
+       while (t) {
+               ++ndigits;
+               t >>= SHIFT;
+       }
+       v = _PyLong_New(ndigits);
+       if (v != NULL) {
+               digit *p = v->ob_digit;
+               v->ob_size = ndigits;
+               while (ival) {
+                       *p++ = (digit)(ival & MASK);
+                       ival >>= SHIFT;
+               }
+       }
+       return (PyObject *)v;
 }
 
 /* Create a new long int object from a C Py_ssize_t. */