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_CAST(so) \
      62      (assert(PyAnySet_Check(so)), _Py_CAST(PySetObject*, so))
      63  
      64  static inline Py_ssize_t PySet_GET_SIZE(PyObject *so) {
      65      return _PySet_CAST(so)->used;
      66  }
      67  #define PySet_GET_SIZE(so) PySet_GET_SIZE(_PyObject_CAST(so))
      68  
      69  PyAPI_DATA(PyObject *) _PySet_Dummy;
      70  
      71  PyAPI_FUNC(int) _PySet_NextEntry(PyObject *set, Py_ssize_t *pos, PyObject **key, Py_hash_t *hash);
      72  PyAPI_FUNC(int) _PySet_Update(PyObject *set, PyObject *iterable);