bpo-42924: Fix incorrect copy in bytearray_repeat (GH-24208)
Before, using the * operator to repeat a bytearray would copy data from the start of
the internal buffer (ob_bytes) and not from the start of the actual data (ob_start).
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 7cb2b14..2eaca5c 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -321,6 +321,7 @@ bytearray_repeat(PyByteArrayObject *self, Py_ssize_t count)
PyByteArrayObject *result;
Py_ssize_t mysize;
Py_ssize_t size;
+ const char *buf;
if (count < 0)
count = 0;
@@ -329,13 +330,14 @@ bytearray_repeat(PyByteArrayObject *self, Py_ssize_t count)
return PyErr_NoMemory();
size = mysize * count;
result = (PyByteArrayObject *)PyByteArray_FromStringAndSize(NULL, size);
+ buf = PyByteArray_AS_STRING(self);
if (result != NULL && size != 0) {
if (mysize == 1)
- memset(result->ob_bytes, self->ob_bytes[0], size);
+ memset(result->ob_bytes, buf[0], size);
else {
Py_ssize_t i;
for (i = 0; i < count; i++)
- memcpy(result->ob_bytes + i*mysize, self->ob_bytes, mysize);
+ memcpy(result->ob_bytes + i*mysize, buf, mysize);
}
}
return (PyObject *)result;