Merged revisions 60481,60485,60489-60492,60494-60496,60498-60499,60501-60503,60505-60506,60508-60509,60523-60524,60532,60543,60545,60547-60548,60552,60554,60556-60559,60561-60562,60569,60571-60572,60574,60576-60583,60585-60586,60589,60591,60594-60595,60597-60598,60600-60601,60606-60612,60615,60617,60619-60621,60623-60625,60627-60629,60631,60633,60635,60647,60650,60652,60654,60656,60658-60659,60664-60666,60668-60670,60672,60676,60678,60680-60683,60685-60686,60688,60690,60692-60694,60697-60700,60705-60706,60708,60711,60714,60720,60724-60730,60732,60736,60742,60744,60746,60748,60750-60751,60753,60756-60757,60759-60761,60763-60764,60766,60769-60770,60774-60784,60787-60789,60793,60796,60799-60809,60812-60813,60815-60821,60823-60826,60828-60829,60831-60834,60836,60838-60839,60846-60849,60852-60854,60856-60859,60861-60870,60874-60875,60880-60881,60886,60888-60890,60892,60894-60898,60900,60902-60906,60908,60911-60917,60919-60920,60922,60926,60929-60931,60933-60935,60937,60939-60941,60943-60954,60959-60961,60963-60969,60971-60976 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r60965 | eric.smith | 2008-02-22 18:43:17 +0100 (Fri, 22 Feb 2008) | 1 line

  Tests for bin() builtin.  These need to get merged into py3k, which has no tests for bin.
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  r60968 | raymond.hettinger | 2008-02-22 20:50:06 +0100 (Fri, 22 Feb 2008) | 1 line

  Document itertools.product().
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  r60969 | raymond.hettinger | 2008-02-23 03:20:41 +0100 (Sat, 23 Feb 2008) | 9 lines

  Improve the implementation of itertools.product()

  * Fix-up issues pointed-out by Neal Norwitz.
  * Add extensive comments.
  * The lz->result variable is now a tuple instead of a list.
  * Use fast macro getitem/setitem calls so most code is in-line.
  * Re-use the result tuple if available (modify in-place instead of copy).
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  r60972 | raymond.hettinger | 2008-02-23 05:03:50 +0100 (Sat, 23 Feb 2008) | 1 line

  Add more comments
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  r60973 | raymond.hettinger | 2008-02-23 11:04:15 +0100 (Sat, 23 Feb 2008) | 1 line

  Add recipe using itertools.product().
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  r60974 | facundo.batista | 2008-02-23 13:01:13 +0100 (Sat, 23 Feb 2008) | 6 lines


  Issue 1881. Increased the stack limit from 500 to 1500. Also added
  a test for this (and because of this test you'll see in stderr a
  message that parser.c sends before raising MemoryError).
  Thanks Ralf Schmitt.
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  r60975 | facundo.batista | 2008-02-23 13:27:17 +0100 (Sat, 23 Feb 2008) | 4 lines


  Issue 1776581. Minor corrections to smtplib, and two small tests.
  Thanks Alan McIntyre.
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  r60976 | facundo.batista | 2008-02-23 13:46:10 +0100 (Sat, 23 Feb 2008) | 5 lines


  Issue 1781. Now ConfigParser.add_section does not let you add a
  DEFAULT section any more, because it duplicated sections with
  the rest of the machinery. Thanks Tim Lesher and Manuel Kaufmann.
........

1 files changed, 47 insertions, 16 deletions

diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 613515a..5b6aec3 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -1716,10 +1716,10 @@ static PyTypeObject chain_type = {
 typedef struct {
 	PyObject_HEAD
 	PyObject *pools;		/* tuple of pool tuples */
-	Py_ssize_t *maxvec;
-	Py_ssize_t *indices;
-	PyObject *result;
-	int stopped;
+	Py_ssize_t *maxvec;             /* size of each pool */
+	Py_ssize_t *indices;            /* one index per pool */
+	PyObject *result;               /* most recently returned result tuple */
+	int stopped;                    /* set to 1 when the product iterator is exhausted */
 } productobject;
 
 static PyTypeObject product_type;
@@ -1766,7 +1766,7 @@ product_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	lz = (productobject *)type->tp_alloc(type, 0);
 	if (lz == NULL) {
 		Py_DECREF(pools);
-		return NULL;
+		goto error;
 	}
 
 	lz->pools = pools;
@@ -1810,7 +1810,7 @@ product_next(productobject *lz)
 {
 	PyObject *pool;
 	PyObject *elem;
-	PyObject *tuple_result;
+	PyObject *oldelem;
 	PyObject *pools = lz->pools;
 	PyObject *result = lz->result;
 	Py_ssize_t npools = PyTuple_GET_SIZE(pools);
@@ -1818,10 +1818,14 @@ product_next(productobject *lz)
 
 	if (lz->stopped)
 		return NULL;
+
 	if (result == NULL) {
+                /* On the first pass, return an initial tuple filled with the 
+                   first element from each pool.  If any pool is empty, then 
+                   whole product is empty and we're already done */
 		if (npools == 0)
 			goto empty;
-		result = PyList_New(npools);
+		result = PyTuple_New(npools);
 		if (result == NULL)
             		goto empty;
 		lz->result = result;
@@ -1831,34 +1835,61 @@ product_next(productobject *lz)
 				goto empty;
     			elem = PyTuple_GET_ITEM(pool, 0);
     			Py_INCREF(elem);
-    			PyList_SET_ITEM(result, i, elem);
+    			PyTuple_SET_ITEM(result, i, elem);
 		}
 	} else {
 		Py_ssize_t *indices = lz->indices;
 		Py_ssize_t *maxvec = lz->maxvec;
+
+		/* Copy the previous result tuple or re-use it if available */
+		if (Py_REFCNT(result) > 1) {
+			PyObject *old_result = result;
+			result = PyTuple_New(npools);
+			if (result == NULL)
+				goto empty;
+			lz->result = result;
+			for (i=0; i < npools; i++) {
+				elem = PyTuple_GET_ITEM(old_result, i);
+    				Py_INCREF(elem);
+    				PyTuple_SET_ITEM(result, i, elem);
+			}
+			Py_DECREF(old_result);
+		}
+		/* Now, we've got the only copy so we can update it in-place */
+		assert (Py_REFCNT(result) == 1);
+
+                /* Update the pool indices right-to-left.  Only advance to the
+                   next pool when the previous one rolls-over */
 		for (i=npools-1 ; i >= 0 ; i--) {
 			pool = PyTuple_GET_ITEM(pools, i);
 			indices[i]++;
 			if (indices[i] == maxvec[i]) {
+				/* Roll-over and advance to next pool */
 				indices[i] = 0;
 				elem = PyTuple_GET_ITEM(pool, 0);
 				Py_INCREF(elem);
-				PyList_SetItem(result, i, elem);
+				oldelem = PyTuple_GET_ITEM(result, i);
+				PyTuple_SET_ITEM(result, i, elem);
+				Py_DECREF(oldelem);
 			} else {
+				/* No rollover. Just increment and stop here. */
 				elem = PyTuple_GET_ITEM(pool, indices[i]);
 				Py_INCREF(elem);
-				PyList_SetItem(result, i, elem);
+				oldelem = PyTuple_GET_ITEM(result, i);
+				PyTuple_SET_ITEM(result, i, elem);
+				Py_DECREF(oldelem);
 				break;
 			}
 		}
+
+		/* If i is negative, then the indices have all rolled-over
+                   and we're done. */
 		if (i < 0)
-			return NULL;
+			goto empty;
 	}
 
-	tuple_result = PySequence_Tuple(result);
-	if (tuple_result == NULL)
-		lz->stopped = 1;
-	return tuple_result;
+	Py_INCREF(result);
+	return result;
 
 empty:
 	lz->stopped = 1;
@@ -1868,7 +1899,7 @@ empty:
 PyDoc_STRVAR(product_doc,
 "product(*iterables) --> product object\n\
 \n\
-Cartesian product of input interables.  Equivalent to nested for-loops.\n\n\
+Cartesian product of input iterables.  Equivalent to nested for-loops.\n\n\
 For example, product(A, B) returns the same as:  ((x,y) for x in A for y in B).\n\
 The leftmost iterators are in the outermost for-loop, so the output tuples\n\
 cycle in a manner similar to an odometer (with the rightmost element changing\n\