1 #ifndef Py_INTERNAL_HAMT_H 2 #define Py_INTERNAL_HAMT_H 3 4 #ifndef Py_BUILD_CORE 5 # error "this header requires Py_BUILD_CORE define" 6 #endif 7 8 9 /* 10 HAMT tree is shaped by hashes of keys. Every group of 5 bits of a hash denotes 11 the exact position of the key in one level of the tree. Since we're using 12 32 bit hashes, we can have at most 7 such levels. Although if there are 13 two distinct keys with equal hashes, they will have to occupy the same 14 cell in the 7th level of the tree -- so we'd put them in a "collision" node. 15 Which brings the total possible tree depth to 8. Read more about the actual 16 layout of the HAMT tree in `hamt.c`. 17 18 This constant is used to define a datastucture for storing iteration state. 19 */ 20 #define _Py_HAMT_MAX_TREE_DEPTH 8 21 22 23 extern PyTypeObject _PyHamt_Type; 24 extern PyTypeObject _PyHamt_ArrayNode_Type; 25 extern PyTypeObject _PyHamt_BitmapNode_Type; 26 extern PyTypeObject _PyHamt_CollisionNode_Type; 27 extern PyTypeObject _PyHamtKeys_Type; 28 extern PyTypeObject _PyHamtValues_Type; 29 extern PyTypeObject _PyHamtItems_Type; 30 31 32 /* other API */ 33 34 #define PyHamt_Check(o) Py_IS_TYPE((o), &_PyHamt_Type) 35 36 37 /* Abstract tree node. */ 38 typedef struct { 39 PyObject_HEAD 40 } PyHamtNode; 41 42 43 /* An HAMT immutable mapping collection. */ 44 typedef struct { 45 PyObject_HEAD 46 PyHamtNode *h_root; 47 PyObject *h_weakreflist; 48 Py_ssize_t h_count; 49 } PyHamtObject; 50 51 52 typedef struct { 53 PyObject_VAR_HEAD 54 uint32_t b_bitmap; 55 PyObject *b_array[1]; 56 } PyHamtNode_Bitmap; 57 58 59 /* A struct to hold the state of depth-first traverse of the tree. 60 61 HAMT is an immutable collection. Iterators will hold a strong reference 62 to it, and every node in the HAMT has strong references to its children. 63 64 So for iterators, we can implement zero allocations and zero reference 65 inc/dec depth-first iteration. 66 67 - i_nodes: an array of seven pointers to tree nodes 68 - i_level: the current node in i_nodes 69 - i_pos: an array of positions within nodes in i_nodes. 70 */ 71 typedef struct { 72 PyHamtNode *i_nodes[_Py_HAMT_MAX_TREE_DEPTH]; 73 Py_ssize_t i_pos[_Py_HAMT_MAX_TREE_DEPTH]; 74 int8_t i_level; 75 } PyHamtIteratorState; 76 77 78 /* Base iterator object. 79 80 Contains the iteration state, a pointer to the HAMT tree, 81 and a pointer to the 'yield function'. The latter is a simple 82 function that returns a key/value tuple for the 'Items' iterator, 83 just a key for the 'Keys' iterator, and a value for the 'Values' 84 iterator. 85 */ 86 typedef struct { 87 PyObject_HEAD 88 PyHamtObject *hi_obj; 89 PyHamtIteratorState hi_iter; 90 binaryfunc hi_yield; 91 } PyHamtIterator; 92 93 94 /* Create a new HAMT immutable mapping. */ 95 PyHamtObject * _PyHamt_New(void); 96 97 /* Return a new collection based on "o", but with an additional 98 key/val pair. */ 99 PyHamtObject * _PyHamt_Assoc(PyHamtObject *o, PyObject *key, PyObject *val); 100 101 /* Return a new collection based on "o", but without "key". */ 102 PyHamtObject * _PyHamt_Without(PyHamtObject *o, PyObject *key); 103 104 /* Find "key" in the "o" collection. 105 106 Return: 107 - -1: An error occurred. 108 - 0: "key" wasn't found in "o". 109 - 1: "key" is in "o"; "*val" is set to its value (a borrowed ref). 110 */ 111 int _PyHamt_Find(PyHamtObject *o, PyObject *key, PyObject **val); 112 113 /* Check if "v" is equal to "w". 114 115 Return: 116 - 0: v != w 117 - 1: v == w 118 - -1: An error occurred. 119 */ 120 int _PyHamt_Eq(PyHamtObject *v, PyHamtObject *w); 121 122 /* Return the size of "o"; equivalent of "len(o)". */ 123 Py_ssize_t _PyHamt_Len(PyHamtObject *o); 124 125 /* Return a Keys iterator over "o". */ 126 PyObject * _PyHamt_NewIterKeys(PyHamtObject *o); 127 128 /* Return a Values iterator over "o". */ 129 PyObject * _PyHamt_NewIterValues(PyHamtObject *o); 130 131 /* Return a Items iterator over "o". */ 132 PyObject * _PyHamt_NewIterItems(PyHamtObject *o); 133 134 #endif /* !Py_INTERNAL_HAMT_H */ 135