[Python-checkins] cpython: Issue #27005: Optimized the float.fromhex() class method for exact float.

[serhiy.storchaka]

https://hg.python.org/cpython/rev/3b19660611a4
changeset:   101302:3b19660611a4
user:        Serhiy Storchaka <storchaka at gmail.com>
date:        Thu May 12 10:21:14 2016 +0300
summary:
  Issue #27005: Optimized the float.fromhex() class method for exact float.

files:
  Misc/NEWS             |   3 +++
  Objects/floatobject.c |  11 +++++------
  2 files changed, 8 insertions(+), 6 deletions(-)


diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #27005: Optimized the float.fromhex() class method for exact float.
+  It is now 2 times faster.
+
 - Issue #18531: Single var-keyword argument of dict subtype was passed
   unscathed to the C-defined function.  Now it is converted to exact dict.
 
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -1195,7 +1195,7 @@
 static PyObject *
 float_fromhex(PyObject *cls, PyObject *arg)
 {
-    PyObject *result_as_float, *result;
+    PyObject *result;
     double x;
     long exp, top_exp, lsb, key_digit;
     char *s, *coeff_start, *s_store, *coeff_end, *exp_start, *s_end;
@@ -1410,11 +1410,10 @@
         s++;
     if (s != s_end)
         goto parse_error;
-    result_as_float = Py_BuildValue("(d)", negate ? -x : x);
-    if (result_as_float == NULL)
-        return NULL;
-    result = PyObject_CallObject(cls, result_as_float);
-    Py_DECREF(result_as_float);
+    result = PyFloat_FromDouble(negate ? -x : x);
+    if (cls != (PyObject *)&PyFloat_Type && result != NULL) {
+        Py_SETREF(result, PyObject_CallFunctionObjArgs(cls, result));
+    }
     return result;
 
   overflow_error:

-- 
Repository URL: https://hg.python.org/cpython