[Jython-checkins] SF.net SVN: jython:[6865] trunk/jython/src/org/python/core/Py.java

[<pj...@us...>]

Revision: 6865
          http://jython.svn.sourceforge.net/jython/?rev=6865&view=rev
Author:   pjenvey
Date:     2009-10-17 02:11:46 +0000 (Sat, 17 Oct 2009)

Log Message:
-----------
fast path lists along with tuples and avoid the overhead of __len__'ing
generators which can be a somewhat common make_array argument

Modified Paths:
--------------
    trunk/jython/src/org/python/core/Py.java

Modified: trunk/jython/src/org/python/core/Py.java
===================================================================
--- trunk/jython/src/org/python/core/Py.java	2009-10-16 05:51:46 UTC (rev 6864)
+++ trunk/jython/src/org/python/core/Py.java	2009-10-17 02:11:46 UTC (rev 6865)
@@ -1904,23 +1904,29 @@
         }
     }
 
-    static PyObject[] make_array(PyObject o) {
-        if (o instanceof PyTuple) {
-            return ((PyTuple) o).getArray();
+    static PyObject[] make_array(PyObject iterable) {
+        // Special-case the common tuple and list cases, for efficiency
+        if (iterable instanceof PySequenceList) {
+            return ((PySequenceList) iterable).getArray();
         }
-        // Guess result size and allocate space.
+
+        // Guess result size and allocate space. The typical make_array arg supports
+        // __len__, with one exception being generators, so avoid the overhead of an
+        // exception from __len__ in their case
         int n = 10;
-        try {
-            n = o.__len__();
-        } catch (PyException exc) {
+        if (!(iterable instanceof PyGenerator)) {
+            try {
+                n = iterable.__len__();
+            } catch (PyException pye) {
+                // ok
+            }
         }
 
         List<PyObject> objs = new ArrayList<PyObject>(n);
-        for (PyObject item : o.asIterable()) {
+        for (PyObject item : iterable.asIterable()) {
             objs.add(item);
         }
-        PyObject dest[] = new PyObject[0];
-        return (objs.toArray(dest));
+        return objs.toArray(Py.EmptyObjects);
     }
 }
 


This was sent by the SourceForge.net collaborative development platform, the world's largest Open Source development site.