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 
7 1. Unused:  key == NULL and hash == 0
8 2. Dummy:   key == dummy and hash == -1
9 3. Active:  key != NULL and key != dummy and hash != -1
10 
11 The hash field of Unused slots is always zero.
12 
13 The hash field of Dummy slots are set to -1
14 meaning that dummy entries can be detected by
15 either entry->key==dummy or by entry->hash==-1.
16 */
17 
18 #define PySet_MINSIZE 8
19 
20 typedef 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 
27 Invariant for sets:
28  - hash is -1
29 
30 Invariants for frozensets:
31  - data is immutable.
32  - hash is the hash of the frozenset or -1 if not computed yet.
33 
34 */
35 
36 typedef 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 
64 PyAPI_DATA(PyObject *) _PySet_Dummy;
65 
66 PyAPI_FUNC(int) _PySet_NextEntry(PyObject *set, Py_ssize_t *pos, PyObject **key, Py_hash_t *hash);
67 PyAPI_FUNC(int) _PySet_Update(PyObject *set, PyObject *iterable);
68