Optimize slicing of bytes and bytearray by avoiding useless copying.
This restores the behavior that was present in Python 2.x.
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 428ee57..fc12452 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -411,18 +411,18 @@
}
else {
char *source_buf = PyByteArray_AS_STRING(self);
- char *result_buf = (char *)PyMem_Malloc(slicelength);
+ char *result_buf;
PyObject *result;
- if (result_buf == NULL)
- return PyErr_NoMemory();
+ result = PyByteArray_FromStringAndSize(NULL, slicelength);
+ if (result == NULL)
+ return NULL;
+ result_buf = PyByteArray_AS_STRING(result);
for (cur = start, i = 0; i < slicelength;
cur += step, i++) {
result_buf[i] = source_buf[cur];
}
- result = PyByteArray_FromStringAndSize(result_buf, slicelength);
- PyMem_Free(result_buf);
return result;
}
}
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index a4a2e65..d3b598e 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -951,19 +951,17 @@
slicelength);
}
else {
- source_buf = PyBytes_AsString((PyObject*)self);
- result_buf = (char *)PyMem_Malloc(slicelength);
- if (result_buf == NULL)
- return PyErr_NoMemory();
+ source_buf = PyBytes_AS_STRING(self);
+ result = PyBytes_FromStringAndSize(NULL, slicelength);
+ if (result == NULL)
+ return NULL;
+ result_buf = PyBytes_AS_STRING(result);
for (cur = start, i = 0; i < slicelength;
cur += step, i++) {
result_buf[i] = source_buf[cur];
}
- result = PyBytes_FromStringAndSize(result_buf,
- slicelength);
- PyMem_Free(result_buf);
return result;
}
}