/* Set object interface */

#ifndef Py_SETOBJECT_H
#define Py_SETOBJECT_H
#ifdef __cplusplus
extern "C" {
#endif


/*
There are three kinds of slots in the table:

1. Unused: key == NULL
2. Active: key != NULL and key != dummy
3. Dummy: key == dummy

Note: .pop() abuses the hash field of an Unused or Dummy slot to
hold a search finger. The hash field of Unused or Dummy slots has
no meaning otherwise.
*/
#ifndef Py_LIMITED_API
#define PySet_MINSIZE 8

typedef struct {
 /* Cached hash code of the key. */
 PyObject *key;
 Py_hash_t hash;
} setentry;


/*
This data structure is shared by set and frozenset objects.
*/

typedef struct _setobject PySetObject;
struct _setobject {
 PyObject_HEAD

 Py_ssize_t fill; /* # Active + # Dummy */
 Py_ssize_t used; /* # Active */

 /* The table contains mask + 1 slots, and that's a power of 2.
 * We store the mask instead of the size because the mask is more
 * frequently needed.
 */
 Py_ssize_t mask;

 /* table points to smalltable for small tables, else to
 * additional malloc'ed memory. table is never NULL! This rule
 * saves repeated runtime null-tests.
 */
 setentry *table;
 setentry *(*lookup)(PySetObject *so, PyObject *key, Py_hash_t hash);
 Py_hash_t hash; /* only used by frozenset objects */
 setentry smalltable[PySet_MINSIZE];

 PyObject *weakreflist; /* List of weak references */
};
#endif /* Py_LIMITED_API */

PyAPI_DATA(PyTypeObject) PySet_Type;
PyAPI_DATA(PyTypeObject) PyFrozenSet_Type;
PyAPI_DATA(PyTypeObject) PySetIter_Type;
#ifndef Py_LIMITED_API
PyAPI_DATA(PyObject *) _PySet_Dummy;
#endif


/* Invariants for frozensets:
 * data is immutable.
 * hash is the hash of the frozenset or -1 if not computed yet.
 * Invariants for sets:
 * hash is -1
 */

#define PyFrozenSet_CheckExact(ob) (Py_TYPE(ob) == &PyFrozenSet_Type)
#define PyAnySet_CheckExact(ob) \
 (Py_TYPE(ob) == &PySet_Type || Py_TYPE(ob) == &PyFrozenSet_Type)
#define PyAnySet_Check(ob) \
 (Py_TYPE(ob) == &PySet_Type || Py_TYPE(ob) == &PyFrozenSet_Type || \
 PyType_IsSubtype(Py_TYPE(ob), &PySet_Type) || \
 PyType_IsSubtype(Py_TYPE(ob), &PyFrozenSet_Type))
#define PySet_Check(ob) \
 (Py_TYPE(ob) == &PySet_Type || \
 PyType_IsSubtype(Py_TYPE(ob), &PySet_Type))
#define PyFrozenSet_Check(ob) \
 (Py_TYPE(ob) == &PyFrozenSet_Type || \
 PyType_IsSubtype(Py_TYPE(ob), &PyFrozenSet_Type))

PyAPI_FUNC(PyObject *) PySet_New(PyObject *);
PyAPI_FUNC(PyObject *) PyFrozenSet_New(PyObject *);
PyAPI_FUNC(Py_ssize_t) PySet_Size(PyObject *anyset);
#ifndef Py_LIMITED_API
#define PySet_GET_SIZE(so) (((PySetObject *)(so))->used)
#endif
PyAPI_FUNC(int) PySet_Clear(PyObject *set);
PyAPI_FUNC(int) PySet_Contains(PyObject *anyset, PyObject *key);
PyAPI_FUNC(int) PySet_Discard(PyObject *set, PyObject *key);
PyAPI_FUNC(int) PySet_Add(PyObject *set, PyObject *key);
#ifndef Py_LIMITED_API
PyAPI_FUNC(int) _PySet_NextEntry(PyObject *set, Py_ssize_t *pos, PyObject **key, Py_hash_t *hash);
#endif
PyAPI_FUNC(PyObject *) PySet_Pop(PyObject *set);
#ifndef Py_LIMITED_API
PyAPI_FUNC(int) _PySet_Update(PyObject *set, PyObject *iterable);

PyAPI_FUNC(int) PySet_ClearFreeList(void);
#endif

#ifdef __cplusplus
}
#endif
#endif /* !Py_SETOBJECT_H */