You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
132 lines
5.1 KiB
132 lines
5.1 KiB
#ifndef Py_DICTOBJECT_H |
|
#define Py_DICTOBJECT_H |
|
#ifdef __cplusplus |
|
extern "C" { |
|
#endif |
|
|
|
|
|
/* Dictionary object type -- mapping from hashable object to object */ |
|
|
|
/* The distribution includes a separate file, Objects/dictnotes.txt, |
|
describing explorations into dictionary design and optimization. |
|
It covers typical dictionary use patterns, the parameters for |
|
tuning dictionaries, and several ideas for possible optimizations. |
|
*/ |
|
|
|
/* |
|
There are three kinds of slots in the table: |
|
|
|
1. Unused. me_key == me_value == NULL |
|
Does not hold an active (key, value) pair now and never did. Unused can |
|
transition to Active upon key insertion. This is the only case in which |
|
me_key is NULL, and is each slot's initial state. |
|
|
|
2. Active. me_key != NULL and me_key != dummy and me_value != NULL |
|
Holds an active (key, value) pair. Active can transition to Dummy upon |
|
key deletion. This is the only case in which me_value != NULL. |
|
|
|
3. Dummy. me_key == dummy and me_value == NULL |
|
Previously held an active (key, value) pair, but that was deleted and an |
|
active pair has not yet overwritten the slot. Dummy can transition to |
|
Active upon key insertion. Dummy slots cannot be made Unused again |
|
(cannot have me_key set to NULL), else the probe sequence in case of |
|
collision would have no way to know they were once active. |
|
|
|
Note: .popitem() abuses the me_hash field of an Unused or Dummy slot to |
|
hold a search finger. The me_hash field of Unused or Dummy slots has no |
|
meaning otherwise. |
|
*/ |
|
|
|
/* PyDict_MINSIZE is the minimum size of a dictionary. This many slots are |
|
* allocated directly in the dict object (in the ma_smalltable member). |
|
* It must be a power of 2, and at least 4. 8 allows dicts with no more |
|
* than 5 active entries to live in ma_smalltable (and so avoid an |
|
* additional malloc); instrumentation suggested this suffices for the |
|
* majority of dicts (consisting mostly of usually-small instance dicts and |
|
* usually-small dicts created to pass keyword arguments). |
|
*/ |
|
#define PyDict_MINSIZE 8 |
|
|
|
typedef struct { |
|
long me_hash; /* cached hash code of me_key */ |
|
PyObject *me_key; |
|
PyObject *me_value; |
|
} PyDictEntry; |
|
|
|
/* |
|
To ensure the lookup algorithm terminates, there must be at least one Unused |
|
slot (NULL key) in the table. |
|
The value ma_fill is the number of non-NULL keys (sum of Active and Dummy); |
|
ma_used is the number of non-NULL, non-dummy keys (== the number of non-NULL |
|
values == the number of Active items). |
|
To avoid slowing down lookups on a near-full table, we resize the table when |
|
it's two-thirds full. |
|
*/ |
|
typedef struct _dictobject PyDictObject; |
|
struct _dictobject { |
|
PyObject_HEAD |
|
int ma_fill; /* # Active + # Dummy */ |
|
int ma_used; /* # Active */ |
|
|
|
/* The table contains ma_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. |
|
*/ |
|
int ma_mask; |
|
|
|
/* ma_table points to ma_smalltable for small tables, else to |
|
* additional malloc'ed memory. ma_table is never NULL! This rule |
|
* saves repeated runtime null-tests in the workhorse getitem and |
|
* setitem calls. |
|
*/ |
|
PyDictEntry *ma_table; |
|
PyDictEntry *(*ma_lookup)(PyDictObject *mp, PyObject *key, long hash); |
|
PyDictEntry ma_smalltable[PyDict_MINSIZE]; |
|
}; |
|
|
|
PyAPI_DATA(PyTypeObject) PyDict_Type; |
|
|
|
#define PyDict_Check(op) PyObject_TypeCheck(op, &PyDict_Type) |
|
|
|
PyAPI_FUNC(PyObject *) PyDict_New(void); |
|
PyAPI_FUNC(PyObject *) PyDict_GetItem(PyObject *mp, PyObject *key); |
|
PyAPI_FUNC(int) PyDict_SetItem(PyObject *mp, PyObject *key, PyObject *item); |
|
PyAPI_FUNC(int) PyDict_DelItem(PyObject *mp, PyObject *key); |
|
PyAPI_FUNC(void) PyDict_Clear(PyObject *mp); |
|
PyAPI_FUNC(int) PyDict_Next( |
|
PyObject *mp, int *pos, PyObject **key, PyObject **value); |
|
PyAPI_FUNC(PyObject *) PyDict_Keys(PyObject *mp); |
|
PyAPI_FUNC(PyObject *) PyDict_Values(PyObject *mp); |
|
PyAPI_FUNC(PyObject *) PyDict_Items(PyObject *mp); |
|
PyAPI_FUNC(int) PyDict_Size(PyObject *mp); |
|
PyAPI_FUNC(PyObject *) PyDict_Copy(PyObject *mp); |
|
|
|
/* PyDict_Update(mp, other) is equivalent to PyDict_Merge(mp, other, 1). */ |
|
PyAPI_FUNC(int) PyDict_Update(PyObject *mp, PyObject *other); |
|
|
|
/* PyDict_Merge updates/merges from a mapping object (an object that |
|
supports PyMapping_Keys() and PyObject_GetItem()). If override is true, |
|
the last occurrence of a key wins, else the first. The Python |
|
dict.update(other) is equivalent to PyDict_Merge(dict, other, 1). |
|
*/ |
|
PyAPI_FUNC(int) PyDict_Merge(PyObject *mp, |
|
PyObject *other, |
|
int override); |
|
|
|
/* PyDict_MergeFromSeq2 updates/merges from an iterable object producing |
|
iterable objects of length 2. If override is true, the last occurrence |
|
of a key wins, else the first. The Python dict constructor dict(seq2) |
|
is equivalent to dict={}; PyDict_MergeFromSeq(dict, seq2, 1). |
|
*/ |
|
PyAPI_FUNC(int) PyDict_MergeFromSeq2(PyObject *d, |
|
PyObject *seq2, |
|
int override); |
|
|
|
PyAPI_FUNC(PyObject *) PyDict_GetItemString(PyObject *dp, const char *key); |
|
PyAPI_FUNC(int) PyDict_SetItemString(PyObject *dp, const char *key, PyObject *item); |
|
PyAPI_FUNC(int) PyDict_DelItemString(PyObject *dp, const char *key); |
|
|
|
#ifdef __cplusplus |
|
} |
|
#endif |
|
#endif /* !Py_DICTOBJECT_H */
|
|
|