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51b4ade306
mutation during list.sort() used to rely on that listobject.c always NULL'ed ob_item when ob_size fell to 0. That's no longer true, so the test for list mutation during a sort is no longer reliable. Changed the test to rely instead on that listobject.c now never NULLs-out ob_item after (if ever) ob_item gets a non-NULL value. This new assumption is also documented now, as a required invariant in listobject.h. The new assumption allowed some real simplification to some of the hairier code in listsort(), so is a Good Thing on that count.
66 lines
2.4 KiB
C
66 lines
2.4 KiB
C
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/* List object interface */
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/*
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Another generally useful object type is an list of object pointers.
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This is a mutable type: the list items can be changed, and items can be
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added or removed. Out-of-range indices or non-list objects are ignored.
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*** WARNING *** PyList_SetItem does not increment the new item's reference
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count, but does decrement the reference count of the item it replaces,
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if not nil. It does *decrement* the reference count if it is *not*
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inserted in the list. Similarly, PyList_GetItem does not increment the
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returned item's reference count.
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*/
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#ifndef Py_LISTOBJECT_H
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#define Py_LISTOBJECT_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct {
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PyObject_VAR_HEAD
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/* Vector of pointers to list elements. list[0] is ob_item{0], etc. */
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PyObject **ob_item;
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/* ob_item contains space for 'allocated' elements. The number
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* currently in use is ob_size.
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* Invariants:
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* 0 <= ob_size <= allocated
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* len(list) == ob_size
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* ob_item == NULL implies ob_size == allocated == 0
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* If ob_item ever becomes non-NULL, it remains non-NULL for the
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* life of the list object. The check for mutation in list.sort()
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* relies on this odd detail.
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*/
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int allocated;
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} PyListObject;
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PyAPI_DATA(PyTypeObject) PyList_Type;
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#define PyList_Check(op) PyObject_TypeCheck(op, &PyList_Type)
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#define PyList_CheckExact(op) ((op)->ob_type == &PyList_Type)
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PyAPI_FUNC(PyObject *) PyList_New(int size);
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PyAPI_FUNC(int) PyList_Size(PyObject *);
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PyAPI_FUNC(PyObject *) PyList_GetItem(PyObject *, int);
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PyAPI_FUNC(int) PyList_SetItem(PyObject *, int, PyObject *);
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PyAPI_FUNC(int) PyList_Insert(PyObject *, int, PyObject *);
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PyAPI_FUNC(int) PyList_Append(PyObject *, PyObject *);
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PyAPI_FUNC(PyObject *) PyList_GetSlice(PyObject *, int, int);
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PyAPI_FUNC(int) PyList_SetSlice(PyObject *, int, int, PyObject *);
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PyAPI_FUNC(int) PyList_Sort(PyObject *);
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PyAPI_FUNC(int) PyList_Reverse(PyObject *);
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PyAPI_FUNC(PyObject *) PyList_AsTuple(PyObject *);
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PyAPI_FUNC(PyObject *) _PyList_Extend(PyListObject *, PyObject *);
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/* Macro, trading safety for speed */
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#define PyList_GET_ITEM(op, i) (((PyListObject *)(op))->ob_item[i])
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#define PyList_SET_ITEM(op, i, v) (((PyListObject *)(op))->ob_item[i] = (v))
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#define PyList_GET_SIZE(op) (((PyListObject *)(op))->ob_size)
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_LISTOBJECT_H */
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