1#ifndef Py_CPYTHON_SETOBJECT_H
2#  error "this header file must not be included directly"
3#endif
4
5/* There are three kinds of entries in the table:
6
71. Unused:  key == NULL and hash == 0
82. Dummy:   key == dummy and hash == -1
93. Active:  key != NULL and key != dummy and hash != -1
10
11The hash field of Unused slots is always zero.
12
13The hash field of Dummy slots are set to -1
14meaning that dummy entries can be detected by
15either entry->key==dummy or by entry->hash==-1.
16*/
17
18#define PySet_MINSIZE 8
19
20typedef struct {
21    PyObject *key;
22    Py_hash_t hash;             /* Cached hash code of the key */
23} setentry;
24
25/* The SetObject data structure is shared by set and frozenset objects.
26
27Invariant for sets:
28 - hash is -1
29
30Invariants for frozensets:
31 - data is immutable.
32 - hash is the hash of the frozenset or -1 if not computed yet.
33
34*/
35
36typedef struct {
37    PyObject_HEAD
38
39    Py_ssize_t fill;            /* Number active and dummy entries*/
40    Py_ssize_t used;            /* Number active entries */
41
42    /* The table contains mask + 1 slots, and that's a power of 2.
43     * We store the mask instead of the size because the mask is more
44     * frequently needed.
45     */
46    Py_ssize_t mask;
47
48    /* The table points to a fixed-size smalltable for small tables
49     * or to additional malloc'ed memory for bigger tables.
50     * The table pointer is never NULL which saves us from repeated
51     * runtime null-tests.
52     */
53    setentry *table;
54    Py_hash_t hash;             /* Only used by frozenset objects */
55    Py_ssize_t finger;          /* Search finger for pop() */
56
57    setentry smalltable[PySet_MINSIZE];
58    PyObject *weakreflist;      /* List of weak references */
59} PySetObject;
60
61#define PySet_GET_SIZE(so) \
62    (assert(PyAnySet_Check(so)), (((PySetObject *)(so))->used))
63
64PyAPI_DATA(PyObject *) _PySet_Dummy;
65
66PyAPI_FUNC(int) _PySet_NextEntry(PyObject *set, Py_ssize_t *pos, PyObject **key, Py_hash_t *hash);
67PyAPI_FUNC(int) _PySet_Update(PyObject *set, PyObject *iterable);
68