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#ifndef Py_INTERNAL_HAMT_H
#define Py_INTERNAL_HAMT_H
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
/*
HAMT tree is shaped by hashes of keys. Every group of 5 bits of a hash denotes
the exact position of the key in one level of the tree. Since we're using
32 bit hashes, we can have at most 7 such levels. Although if there are
two distinct keys with equal hashes, they will have to occupy the same
cell in the 7th level of the tree -- so we'd put them in a "collision" node.
Which brings the total possible tree depth to 8. Read more about the actual
layout of the HAMT tree in `hamt.c`.
This constant is used to define a datastucture for storing iteration state.
*/
#define _Py_HAMT_MAX_TREE_DEPTH 8
extern PyTypeObject _PyHamt_Type;
extern PyTypeObject _PyHamt_ArrayNode_Type;
extern PyTypeObject _PyHamt_BitmapNode_Type;
extern PyTypeObject _PyHamt_CollisionNode_Type;
extern PyTypeObject _PyHamtKeys_Type;
extern PyTypeObject _PyHamtValues_Type;
extern PyTypeObject _PyHamtItems_Type;
/* other API */
#define PyHamt_Check(o) Py_IS_TYPE((o), &_PyHamt_Type)
/* Abstract tree node. */
typedef struct {
PyObject_HEAD
} PyHamtNode;
/* An HAMT immutable mapping collection. */
typedef struct {
PyObject_HEAD
PyHamtNode *h_root;
PyObject *h_weakreflist;
Py_ssize_t h_count;
} PyHamtObject;
typedef struct {
PyObject_VAR_HEAD
uint32_t b_bitmap;
PyObject *b_array[1];
} PyHamtNode_Bitmap;
/* A struct to hold the state of depth-first traverse of the tree.
HAMT is an immutable collection. Iterators will hold a strong reference
to it, and every node in the HAMT has strong references to its children.
So for iterators, we can implement zero allocations and zero reference
inc/dec depth-first iteration.
- i_nodes: an array of seven pointers to tree nodes
- i_level: the current node in i_nodes
- i_pos: an array of positions within nodes in i_nodes.
*/
typedef struct {
PyHamtNode *i_nodes[_Py_HAMT_MAX_TREE_DEPTH];
Py_ssize_t i_pos[_Py_HAMT_MAX_TREE_DEPTH];
int8_t i_level;
} PyHamtIteratorState;
/* Base iterator object.
Contains the iteration state, a pointer to the HAMT tree,
and a pointer to the 'yield function'. The latter is a simple
function that returns a key/value tuple for the 'Items' iterator,
just a key for the 'Keys' iterator, and a value for the 'Values'
iterator.
*/
typedef struct {
PyObject_HEAD
PyHamtObject *hi_obj;
PyHamtIteratorState hi_iter;
binaryfunc hi_yield;
} PyHamtIterator;
/* Create a new HAMT immutable mapping. */
PyHamtObject * _PyHamt_New(void);
/* Return a new collection based on "o", but with an additional
key/val pair. */
PyHamtObject * _PyHamt_Assoc(PyHamtObject *o, PyObject *key, PyObject *val);
/* Return a new collection based on "o", but without "key". */
PyHamtObject * _PyHamt_Without(PyHamtObject *o, PyObject *key);
/* Find "key" in the "o" collection.
Return:
- -1: An error occurred.
- 0: "key" wasn't found in "o".
- 1: "key" is in "o"; "*val" is set to its value (a borrowed ref).
*/
int _PyHamt_Find(PyHamtObject *o, PyObject *key, PyObject **val);
/* Check if "v" is equal to "w".
Return:
- 0: v != w
- 1: v == w
- -1: An error occurred.
*/
int _PyHamt_Eq(PyHamtObject *v, PyHamtObject *w);
/* Return the size of "o"; equivalent of "len(o)". */
Py_ssize_t _PyHamt_Len(PyHamtObject *o);
/* Return a Keys iterator over "o". */
PyObject * _PyHamt_NewIterKeys(PyHamtObject *o);
/* Return a Values iterator over "o". */
PyObject * _PyHamt_NewIterValues(PyHamtObject *o);
/* Return a Items iterator over "o". */
PyObject * _PyHamt_NewIterItems(PyHamtObject *o);
#endif /* !Py_INTERNAL_HAMT_H */
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