Issue #19087: Improve bytearray allocation in order to allow cheap popping of data at the front (slice deletion).

1 files changed, 6 insertions, 5 deletions

diff --git a/Include/bytearrayobject.h b/Include/bytearrayobject.h
index eccd44c751..19e32a21ea 100644
--- a/Include/bytearrayobject.h
+++ b/Include/bytearrayobject.h
@@ -22,10 +22,11 @@ extern "C" {
 #ifndef Py_LIMITED_API
 typedef struct {
     PyObject_VAR_HEAD
+    Py_ssize_t ob_alloc; /* How many bytes allocated in ob_buffer */
+    char *ob_bytes;      /* Physical backing buffer */
+    char *ob_start;      /* Logical start inside ob_bytes */
     /* XXX(nnorwitz): should ob_exports be Py_ssize_t? */
-    int ob_exports; /* how many buffer exports */
-    Py_ssize_t ob_alloc; /* How many bytes allocated */
-    char *ob_bytes;
+    int ob_exports;      /* How many buffer exports */
 } PyByteArrayObject;
 #endif
 
@@ -49,8 +50,8 @@ PyAPI_FUNC(int) PyByteArray_Resize(PyObject *, Py_ssize_t);
 #ifndef Py_LIMITED_API
 #define PyByteArray_AS_STRING(self) \
     (assert(PyByteArray_Check(self)), \
-     Py_SIZE(self) ? ((PyByteArrayObject *)(self))->ob_bytes : _PyByteArray_empty_string)
-#define PyByteArray_GET_SIZE(self)  (assert(PyByteArray_Check(self)),Py_SIZE(self))
+     Py_SIZE(self) ? ((PyByteArrayObject *)(self))->ob_start : _PyByteArray_empty_string)
+#define PyByteArray_GET_SIZE(self) (assert(PyByteArray_Check(self)), Py_SIZE(self))
 
 PyAPI_DATA(char) _PyByteArray_empty_string[];
 #endif