#ifndef Py_CPYTHON_SETOBJECT_H

#  error "this header file must not be included directly"

#endif

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

1. Unused:  key == NULL and hash == 0

2. Dummy:   key == dummy and hash == -1

3. Active:  key != NULL and key != dummy and hash != -1

The hash field of Unused slots is always zero.

The hash field of Dummy slots are set to -1

meaning that dummy entries can be detected by

either entry->key==dummy or by entry->hash==-1.

*/

#define PySet_MINSIZE 8

typedef struct {

    PyObject *key;

    Py_hash_t hash;             /* Cached hash code of the key */

} setentry;

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

Invariant for sets:

 - hash is -1

Invariants for frozensets:

 - data is immutable.

 - hash is the hash of the frozenset or -1 if not computed yet.

*/

typedef struct {

    PyObject_HEAD

    Py_ssize_t fill;            /* Number active and dummy entries*/

    Py_ssize_t used;            /* Number active entries */

    /* 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;

    /* The table points to a fixed-size smalltable for small tables

     * or to additional malloc'ed memory for bigger tables.

     * The table pointer is never NULL which saves us from repeated

     * runtime null-tests.

     */

    setentry *table;

    Py_hash_t hash;             /* Only used by frozenset objects */

    Py_ssize_t finger;          /* Search finger for pop() */

    setentry smalltable[PySet_MINSIZE];

    PyObject *weakreflist;      /* List of weak references */

} PySetObject;

#define _PySet_CAST(so) \

    (assert(PyAnySet_Check(so)), _Py_CAST(PySetObject*, so))

static inline Py_ssize_t PySet_GET_SIZE(PyObject *so) {

#ifdef Py_GIL_DISABLED

    return _Py_atomic_load_ssize_relaxed(&(_PySet_CAST(so)->used));

#else

    return _PySet_CAST(so)->used;

#endif

}

#define PySet_GET_SIZE(so) PySet_GET_SIZE(_PyObject_CAST(so))