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diff --git a/Python/hamt.c b/Python/hamt.c new file mode 100644 index 0000000..8ba5082 --- /dev/null +++ b/Python/hamt.c @@ -0,0 +1,2982 @@ +#include "Python.h" + +#include "structmember.h" +#include "internal/pystate.h" +#include "internal/hamt.h" + +/* popcnt support in Visual Studio */ +#ifdef _MSC_VER +#include <intrin.h> +#endif + +/* +This file provides an implemention of an immutable mapping using the +Hash Array Mapped Trie (or HAMT) datastructure. + +This design allows to have: + +1. Efficient copy: immutable mappings can be copied by reference, + making it an O(1) operation. + +2. Efficient mutations: due to structural sharing, only a portion of + the trie needs to be copied when the collection is mutated. The + cost of set/delete operations is O(log N). + +3. Efficient lookups: O(log N). + +(where N is number of key/value items in the immutable mapping.) + + +HAMT +==== + +The core idea of HAMT is that the shape of the trie is encoded into the +hashes of keys. + +Say we want to store a K/V pair in our mapping. First, we calculate the +hash of K, let's say it's 19830128, or in binary: + + 0b1001011101001010101110000 = 19830128 + +Now let's partition this bit representation of the hash into blocks of +5 bits each: + + 0b00_00000_10010_11101_00101_01011_10000 = 19830128 + (6) (5) (4) (3) (2) (1) + +Each block of 5 bits represents a number betwen 0 and 31. So if we have +a tree that consists of nodes, each of which is an array of 32 pointers, +those 5-bit blocks will encode a position on a single tree level. + +For example, storing the key K with hash 19830128, results in the following +tree structure: + + (array of 32 pointers) + +---+ -- +----+----+----+ -- +----+ + root node | 0 | .. | 15 | 16 | 17 | .. | 31 | 0b10000 = 16 (1) + (level 1) +---+ -- +----+----+----+ -- +----+ + | + +---+ -- +----+----+----+ -- +----+ + a 2nd level node | 0 | .. | 10 | 11 | 12 | .. | 31 | 0b01011 = 11 (2) + +---+ -- +----+----+----+ -- +----+ + | + +---+ -- +----+----+----+ -- +----+ + a 3rd level node | 0 | .. | 04 | 05 | 06 | .. | 31 | 0b01011 = 5 (3) + +---+ -- +----+----+----+ -- +----+ + | + +---+ -- +----+----+----+----+ + a 4th level node | 0 | .. | 04 | 29 | 30 | 31 | 0b11101 = 29 (4) + +---+ -- +----+----+----+----+ + | + +---+ -- +----+----+----+ -- +----+ + a 5th level node | 0 | .. | 17 | 18 | 19 | .. | 31 | 0b10010 = 18 (5) + +---+ -- +----+----+----+ -- +----+ + | + +--------------+ + | + +---+ -- +----+----+----+ -- +----+ + a 6th level node | 0 | .. | 15 | 16 | 17 | .. | 31 | 0b00000 = 0 (6) + +---+ -- +----+----+----+ -- +----+ + | + V -- our value (or collision) + +To rehash: for a K/V pair, the hash of K encodes where in the tree V will +be stored. + +To optimize memory footprint and handle hash collisions, our implementation +uses three different types of nodes: + + * A Bitmap node; + * An Array node; + * A Collision node. + +Because we implement an immutable dictionary, our nodes are also +immutable. Therefore, when we need to modify a node, we copy it, and +do that modification to the copy. + + +Array Nodes +----------- + +These nodes are very simple. Essentially they are arrays of 32 pointers +we used to illustrate the high-level idea in the previous section. + +We use Array nodes only when we need to store more than 16 pointers +in a single node. + +Array nodes do not store key objects or value objects. They are used +only as an indirection level - their pointers point to other nodes in +the tree. + + +Bitmap Node +----------- + +Allocating a new 32-pointers array for every node of our tree would be +very expensive. Unless we store millions of keys, most of tree nodes would +be very sparse. + +When we have less than 16 elements in a node, we don't want to use the +Array node, that would mean that we waste a lot of memory. Instead, +we can use bitmap compression and can have just as many pointers +as we need! + +Bitmap nodes consist of two fields: + +1. An array of pointers. If a Bitmap node holds N elements, the + array will be of N pointers. + +2. A 32bit integer -- a bitmap field. If an N-th bit is set in the + bitmap, it means that the node has an N-th element. + +For example, say we need to store a 3 elements sparse array: + + +---+ -- +---+ -- +----+ -- +----+ + | 0 | .. | 4 | .. | 11 | .. | 17 | + +---+ -- +---+ -- +----+ -- +----+ + | | | + o1 o2 o3 + +We allocate a three-pointer Bitmap node. Its bitmap field will be +then set to: + + 0b_00100_00010_00000_10000 == (1 << 17) | (1 << 11) | (1 << 4) + +To check if our Bitmap node has an I-th element we can do: + + bitmap & (1 << I) + + +And here's a formula to calculate a position in our pointer array +which would correspond to an I-th element: + + popcount(bitmap & ((1 << I) - 1)) + + +Let's break it down: + + * `popcount` is a function that returns a number of bits set to 1; + + * `((1 << I) - 1)` is a mask to filter the bitmask to contain bits + set to the *right* of our bit. + + +So for our 17, 11, and 4 indexes: + + * bitmap & ((1 << 17) - 1) == 0b100000010000 => 2 bits are set => index is 2. + + * bitmap & ((1 << 11) - 1) == 0b10000 => 1 bit is set => index is 1. + + * bitmap & ((1 << 4) - 1) == 0b0 => 0 bits are set => index is 0. + + +To conclude: Bitmap nodes are just like Array nodes -- they can store +a number of pointers, but use bitmap compression to eliminate unused +pointers. + + +Bitmap nodes have two pointers for each item: + + +----+----+----+----+ -- +----+----+ + | k1 | v1 | k2 | v2 | .. | kN | vN | + +----+----+----+----+ -- +----+----+ + +When kI == NULL, vI points to another tree level. + +When kI != NULL, the actual key object is stored in kI, and its +value is stored in vI. + + +Collision Nodes +--------------- + +Collision nodes are simple arrays of pointers -- two pointers per +key/value. When there's a hash collision, say for k1/v1 and k2/v2 +we have `hash(k1)==hash(k2)`. Then our collision node will be: + + +----+----+----+----+ + | k1 | v1 | k2 | v2 | + +----+----+----+----+ + + +Tree Structure +-------------- + +All nodes are PyObjects. + +The `PyHamtObject` object has a pointer to the root node (h_root), +and has a length field (h_count). + +High-level functions accept a PyHamtObject object and dispatch to +lower-level functions depending on what kind of node h_root points to. + + +Operations +========== + +There are three fundamental operations on an immutable dictionary: + +1. "o.assoc(k, v)" will return a new immutable dictionary, that will be + a copy of "o", but with the "k/v" item set. + + Functions in this file: + + hamt_node_assoc, hamt_node_bitmap_assoc, + hamt_node_array_assoc, hamt_node_collision_assoc + + `hamt_node_assoc` function accepts a node object, and calls + other functions depending on its actual type. + +2. "o.find(k)" will lookup key "k" in "o". + + Functions: + + hamt_node_find, hamt_node_bitmap_find, + hamt_node_array_find, hamt_node_collision_find + +3. "o.without(k)" will return a new immutable dictionary, that will be + a copy of "o", buth without the "k" key. + + Functions: + + hamt_node_without, hamt_node_bitmap_without, + hamt_node_array_without, hamt_node_collision_without + + +Further Reading +=============== + +1. http://blog.higher-order.net/2009/09/08/understanding-clojures-persistenthashmap-deftwice.html + +2. http://blog.higher-order.net/2010/08/16/assoc-and-clojures-persistenthashmap-part-ii.html + +3. Clojure's PersistentHashMap implementation: + https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/PersistentHashMap.java + + +Debug +===== + +The HAMT datatype is accessible for testing purposes under the +`_testcapi` module: + + >>> from _testcapi import hamt + >>> h = hamt() + >>> h2 = h.set('a', 2) + >>> h3 = h2.set('b', 3) + >>> list(h3) + ['a', 'b'] + +When CPython is built in debug mode, a '__dump__()' method is available +to introspect the tree: + + >>> print(h3.__dump__()) + HAMT(len=2): + BitmapNode(size=4 count=2 bitmap=0b110 id=0x10eb9d9e8): + 'a': 2 + 'b': 3 +*/ + + +#define IS_ARRAY_NODE(node) (Py_TYPE(node) == &_PyHamt_ArrayNode_Type) +#define IS_BITMAP_NODE(node) (Py_TYPE(node) == &_PyHamt_BitmapNode_Type) +#define IS_COLLISION_NODE(node) (Py_TYPE(node) == &_PyHamt_CollisionNode_Type) + + +/* Return type for 'find' (lookup a key) functions. + + * F_ERROR - an error occurred; + * F_NOT_FOUND - the key was not found; + * F_FOUND - the key was found. +*/ +typedef enum {F_ERROR, F_NOT_FOUND, F_FOUND} hamt_find_t; + + +/* Return type for 'without' (delete a key) functions. + + * W_ERROR - an error occurred; + * W_NOT_FOUND - the key was not found: there's nothing to delete; + * W_EMPTY - the key was found: the node/tree would be empty + if the key is deleted; + * W_NEWNODE - the key was found: a new node/tree is returned + without that key. +*/ +typedef enum {W_ERROR, W_NOT_FOUND, W_EMPTY, W_NEWNODE} hamt_without_t; + + +/* Low-level iterator protocol type. + + * I_ITEM - a new item has been yielded; + * I_END - the whole tree was visited (similar to StopIteration). +*/ +typedef enum {I_ITEM, I_END} hamt_iter_t; + + +#define HAMT_ARRAY_NODE_SIZE 32 + + +typedef struct { + PyObject_HEAD + PyHamtNode *a_array[HAMT_ARRAY_NODE_SIZE]; + Py_ssize_t a_count; +} PyHamtNode_Array; + + +typedef struct { + PyObject_VAR_HEAD + uint32_t b_bitmap; + PyObject *b_array[1]; +} PyHamtNode_Bitmap; + + +typedef struct { + PyObject_VAR_HEAD + int32_t c_hash; + PyObject *c_array[1]; +} PyHamtNode_Collision; + + +static PyHamtNode_Bitmap *_empty_bitmap_node; +static PyHamtObject *_empty_hamt; + + +static PyHamtObject * +hamt_alloc(void); + +static PyHamtNode * +hamt_node_assoc(PyHamtNode *node, + uint32_t shift, int32_t hash, + PyObject *key, PyObject *val, int* added_leaf); + +static hamt_without_t +hamt_node_without(PyHamtNode *node, + uint32_t shift, int32_t hash, + PyObject *key, + PyHamtNode **new_node); + +static hamt_find_t +hamt_node_find(PyHamtNode *node, + uint32_t shift, int32_t hash, + PyObject *key, PyObject **val); + +#ifdef Py_DEBUG +static int +hamt_node_dump(PyHamtNode *node, + _PyUnicodeWriter *writer, int level); +#endif + +static PyHamtNode * +hamt_node_array_new(Py_ssize_t); + +static PyHamtNode * +hamt_node_collision_new(int32_t hash, Py_ssize_t size); + +static inline Py_ssize_t +hamt_node_collision_count(PyHamtNode_Collision *node); + + +#ifdef Py_DEBUG +static void +_hamt_node_array_validate(void *o) +{ + assert(IS_ARRAY_NODE(o)); + PyHamtNode_Array *node = (PyHamtNode_Array*)(o); + Py_ssize_t i = 0, count = 0; + for (; i < HAMT_ARRAY_NODE_SIZE; i++) { + if (node->a_array[i] != NULL) { + count++; + } + } + assert(count == node->a_count); +} + +#define VALIDATE_ARRAY_NODE(NODE) \ + do { _hamt_node_array_validate(NODE); } while (0); +#else +#define VALIDATE_ARRAY_NODE(NODE) +#endif + + +/* Returns -1 on error */ +static inline int32_t +hamt_hash(PyObject *o) +{ + Py_hash_t hash = PyObject_Hash(o); + +#if SIZEOF_PY_HASH_T <= 4 + return hash; +#else + if (hash == -1) { + /* exception */ + return -1; + } + + /* While it's suboptimal to reduce Python's 64 bit hash to + 32 bits via XOR, it seems that the resulting hash function + is good enough (this is also how Long type is hashed in Java.) + Storing 10, 100, 1000 Python strings results in a relatively + shallow and uniform tree structure. + + Please don't change this hashing algorithm, as there are many + tests that test some exact tree shape to cover all code paths. + */ + int32_t xored = (int32_t)(hash & 0xffffffffl) ^ (int32_t)(hash >> 32); + return xored == -1 ? -2 : xored; +#endif +} + +static inline uint32_t +hamt_mask(int32_t hash, uint32_t shift) +{ + return (((uint32_t)hash >> shift) & 0x01f); +} + +static inline uint32_t +hamt_bitpos(int32_t hash, uint32_t shift) +{ + return (uint32_t)1 << hamt_mask(hash, shift); +} + +static inline uint32_t +hamt_bitcount(uint32_t i) +{ +#if defined(__GNUC__) && (__GNUC__ > 4) + return (uint32_t)__builtin_popcountl(i); +#elif defined(__clang__) && (__clang_major__ > 3) + return (uint32_t)__builtin_popcountl(i); +#elif defined(_MSC_VER) + return (uint32_t)__popcnt(i); +#else + /* https://graphics.stanford.edu/~seander/bithacks.html */ + i = i - ((i >> 1) & 0x55555555); + i = (i & 0x33333333) + ((i >> 2) & 0x33333333); + return ((i + (i >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; +#endif +} + +static inline uint32_t +hamt_bitindex(uint32_t bitmap, uint32_t bit) +{ + return hamt_bitcount(bitmap & (bit - 1)); +} + + +/////////////////////////////////// Dump Helpers +#ifdef Py_DEBUG + +static int +_hamt_dump_ident(_PyUnicodeWriter *writer, int level) +{ + /* Write `' ' * level` to the `writer` */ + PyObject *str = NULL; + PyObject *num = NULL; + PyObject *res = NULL; + int ret = -1; + + str = PyUnicode_FromString(" "); + if (str == NULL) { + goto error; + } + + num = PyLong_FromLong((long)level); + if (num == NULL) { + goto error; + } + + res = PyNumber_Multiply(str, num); + if (res == NULL) { + goto error; + } + + ret = _PyUnicodeWriter_WriteStr(writer, res); + +error: + Py_XDECREF(res); + Py_XDECREF(str); + Py_XDECREF(num); + return ret; +} + +static int +_hamt_dump_format(_PyUnicodeWriter *writer, const char *format, ...) +{ + /* A convenient helper combining _PyUnicodeWriter_WriteStr and + PyUnicode_FromFormatV. + */ + PyObject* msg; + int ret; + + va_list vargs; +#ifdef HAVE_STDARG_PROTOTYPES + va_start(vargs, format); +#else + va_start(vargs); +#endif + msg = PyUnicode_FromFormatV(format, vargs); + va_end(vargs); + + if (msg == NULL) { + return -1; + } + + ret = _PyUnicodeWriter_WriteStr(writer, msg); + Py_DECREF(msg); + return ret; +} + +#endif /* Py_DEBUG */ +/////////////////////////////////// Bitmap Node + + +static PyHamtNode * +hamt_node_bitmap_new(Py_ssize_t size) +{ + /* Create a new bitmap node of size 'size' */ + + PyHamtNode_Bitmap *node; + Py_ssize_t i; + + assert(size >= 0); + assert(size % 2 == 0); + + if (size == 0 && _empty_bitmap_node != NULL) { + Py_INCREF(_empty_bitmap_node); + return (PyHamtNode *)_empty_bitmap_node; + } + + /* No freelist; allocate a new bitmap node */ + node = PyObject_GC_NewVar( + PyHamtNode_Bitmap, &_PyHamt_BitmapNode_Type, size); + if (node == NULL) { + return NULL; + } + + Py_SIZE(node) = size; + + for (i = 0; i < size; i++) { + node->b_array[i] = NULL; + } + + node->b_bitmap = 0; + + _PyObject_GC_TRACK(node); + + if (size == 0 && _empty_bitmap_node == NULL) { + /* Since bitmap nodes are immutable, we can cache the instance + for size=0 and reuse it whenever we need an empty bitmap node. + */ + _empty_bitmap_node = node; + Py_INCREF(_empty_bitmap_node); + } + + return (PyHamtNode *)node; +} + +static inline Py_ssize_t +hamt_node_bitmap_count(PyHamtNode_Bitmap *node) +{ + return Py_SIZE(node) / 2; +} + +static PyHamtNode_Bitmap * +hamt_node_bitmap_clone(PyHamtNode_Bitmap *node) +{ + /* Clone a bitmap node; return a new one with the same child notes. */ + + PyHamtNode_Bitmap *clone; + Py_ssize_t i; + + clone = (PyHamtNode_Bitmap *)hamt_node_bitmap_new(Py_SIZE(node)); + if (clone == NULL) { + return NULL; + } + + for (i = 0; i < Py_SIZE(node); i++) { + Py_XINCREF(node->b_array[i]); + clone->b_array[i] = node->b_array[i]; + } + + clone->b_bitmap = node->b_bitmap; + return clone; +} + +static PyHamtNode_Bitmap * +hamt_node_bitmap_clone_without(PyHamtNode_Bitmap *o, uint32_t bit) +{ + assert(bit & o->b_bitmap); + assert(hamt_node_bitmap_count(o) > 1); + + PyHamtNode_Bitmap *new = (PyHamtNode_Bitmap *)hamt_node_bitmap_new( + Py_SIZE(o) - 2); + if (new == NULL) { + return NULL; + } + + uint32_t idx = hamt_bitindex(o->b_bitmap, bit); + uint32_t key_idx = 2 * idx; + uint32_t val_idx = key_idx + 1; + uint32_t i; + + for (i = 0; i < key_idx; i++) { + Py_XINCREF(o->b_array[i]); + new->b_array[i] = o->b_array[i]; + } + + for (i = val_idx + 1; i < Py_SIZE(o); i++) { + Py_XINCREF(o->b_array[i]); + new->b_array[i - 2] = o->b_array[i]; + } + + new->b_bitmap = o->b_bitmap & ~bit; + return new; +} + +static PyHamtNode * +hamt_node_new_bitmap_or_collision(uint32_t shift, + PyObject *key1, PyObject *val1, + int32_t key2_hash, + PyObject *key2, PyObject *val2) +{ + /* Helper method. Creates a new node for key1/val and key2/val2 + pairs. + + If key1 hash is equal to the hash of key2, a Collision node + will be created. If they are not equal, a Bitmap node is + created. + */ + + int32_t key1_hash = hamt_hash(key1); + if (key1_hash == -1) { + return NULL; + } + + if (key1_hash == key2_hash) { + PyHamtNode_Collision *n; + n = (PyHamtNode_Collision *)hamt_node_collision_new(key1_hash, 4); + if (n == NULL) { + return NULL; + } + + Py_INCREF(key1); + n->c_array[0] = key1; + Py_INCREF(val1); + n->c_array[1] = val1; + + Py_INCREF(key2); + n->c_array[2] = key2; + Py_INCREF(val2); + n->c_array[3] = val2; + + return (PyHamtNode *)n; + } + else { + int added_leaf = 0; + PyHamtNode *n = hamt_node_bitmap_new(0); + if (n == NULL) { + return NULL; + } + + PyHamtNode *n2 = hamt_node_assoc( + n, shift, key1_hash, key1, val1, &added_leaf); + Py_DECREF(n); + if (n2 == NULL) { + return NULL; + } + + n = hamt_node_assoc(n2, shift, key2_hash, key2, val2, &added_leaf); + Py_DECREF(n2); + if (n == NULL) { + return NULL; + } + + return n; + } +} + +static PyHamtNode * +hamt_node_bitmap_assoc(PyHamtNode_Bitmap *self, + uint32_t shift, int32_t hash, + PyObject *key, PyObject *val, int* added_leaf) +{ + /* assoc operation for bitmap nodes. + + Return: a new node, or self if key/val already is in the + collection. + + 'added_leaf' is later used in '_PyHamt_Assoc' to determine if + `hamt.set(key, val)` increased the size of the collection. + */ + + uint32_t bit = hamt_bitpos(hash, shift); + uint32_t idx = hamt_bitindex(self->b_bitmap, bit); + + /* Bitmap node layout: + + +------+------+------+------+ --- +------+------+ + | key1 | val1 | key2 | val2 | ... | keyN | valN | + +------+------+------+------+ --- +------+------+ + where `N < Py_SIZE(node)`. + + The `node->b_bitmap` field is a bitmap. For a given + `(shift, hash)` pair we can determine: + + - If this node has the corresponding key/val slots. + - The index of key/val slots. + */ + + if (self->b_bitmap & bit) { + /* The key is set in this node */ + + uint32_t key_idx = 2 * idx; + uint32_t val_idx = key_idx + 1; + + assert(val_idx < Py_SIZE(self)); + + PyObject *key_or_null = self->b_array[key_idx]; + PyObject *val_or_node = self->b_array[val_idx]; + + if (key_or_null == NULL) { + /* key is NULL. This means that we have a few keys + that have the same (hash, shift) pair. */ + + assert(val_or_node != NULL); + + PyHamtNode *sub_node = hamt_node_assoc( + (PyHamtNode *)val_or_node, + shift + 5, hash, key, val, added_leaf); + if (sub_node == NULL) { + return NULL; + } + + if (val_or_node == (PyObject *)sub_node) { + Py_DECREF(sub_node); + Py_INCREF(self); + return (PyHamtNode *)self; + } + + PyHamtNode_Bitmap *ret = hamt_node_bitmap_clone(self); + if (ret == NULL) { + return NULL; + } + Py_SETREF(ret->b_array[val_idx], (PyObject*)sub_node); + return (PyHamtNode *)ret; + } + + assert(key != NULL); + /* key is not NULL. This means that we have only one other + key in this collection that matches our hash for this shift. */ + + int comp_err = PyObject_RichCompareBool(key, key_or_null, Py_EQ); + if (comp_err < 0) { /* exception in __eq__ */ + return NULL; + } + if (comp_err == 1) { /* key == key_or_null */ + if (val == val_or_node) { + /* we already have the same key/val pair; return self. */ + Py_INCREF(self); + return (PyHamtNode *)self; + } + + /* We're setting a new value for the key we had before. + Make a new bitmap node with a replaced value, and return it. */ + PyHamtNode_Bitmap *ret = hamt_node_bitmap_clone(self); + if (ret == NULL) { + return NULL; + } + Py_INCREF(val); + Py_SETREF(ret->b_array[val_idx], val); + return (PyHamtNode *)ret; + } + + /* It's a new key, and it has the same index as *one* another key. + We have a collision. We need to create a new node which will + combine the existing key and the key we're adding. + + `hamt_node_new_bitmap_or_collision` will either create a new + Collision node if the keys have identical hashes, or + a new Bitmap node. + */ + PyHamtNode *sub_node = hamt_node_new_bitmap_or_collision( + shift + 5, + key_or_null, val_or_node, /* existing key/val */ + hash, + key, val /* new key/val */ + ); + if (sub_node == NULL) { + return NULL; + } + + PyHamtNode_Bitmap *ret = hamt_node_bitmap_clone(self); + if (ret == NULL) { + Py_DECREF(sub_node); + return NULL; + } + Py_SETREF(ret->b_array[key_idx], NULL); + Py_SETREF(ret->b_array[val_idx], (PyObject *)sub_node); + + *added_leaf = 1; + return (PyHamtNode *)ret; + } + else { + /* There was no key before with the same (shift,hash). */ + + uint32_t n = hamt_bitcount(self->b_bitmap); + + if (n >= 16) { + /* When we have a situation where we want to store more + than 16 nodes at one level of the tree, we no longer + want to use the Bitmap node with bitmap encoding. + + Instead we start using an Array node, which has + simpler (faster) implementation at the expense of + having prealocated 32 pointers for its keys/values + pairs. + + Small hamt objects (<30 keys) usually don't have any + Array nodes at all. Betwen ~30 and ~400 keys hamt + objects usually have one Array node, and usually it's + a root node. + */ + + uint32_t jdx = hamt_mask(hash, shift); + /* 'jdx' is the index of where the new key should be added + in the new Array node we're about to create. */ + + PyHamtNode *empty = NULL; + PyHamtNode_Array *new_node = NULL; + PyHamtNode *res = NULL; + + /* Create a new Array node. */ + new_node = (PyHamtNode_Array *)hamt_node_array_new(n + 1); + if (new_node == NULL) { + goto fin; + } + + /* Create an empty bitmap node for the next + hamt_node_assoc call. */ + empty = hamt_node_bitmap_new(0); + if (empty == NULL) { + goto fin; + } + + /* Make a new bitmap node for the key/val we're adding. + Set that bitmap node to new-array-node[jdx]. */ + new_node->a_array[jdx] = hamt_node_assoc( + empty, shift + 5, hash, key, val, added_leaf); + if (new_node->a_array[jdx] == NULL) { + goto fin; + } + + /* Copy existing key/value pairs from the current Bitmap + node to the new Array node we've just created. */ + Py_ssize_t i, j; + for (i = 0, j = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + if (((self->b_bitmap >> i) & 1) != 0) { + /* Ensure we don't accidentally override `jdx` element + we set few lines above. + */ + assert(new_node->a_array[i] == NULL); + + if (self->b_array[j] == NULL) { + new_node->a_array[i] = + (PyHamtNode *)self->b_array[j + 1]; + Py_INCREF(new_node->a_array[i]); + } + else { + int32_t rehash = hamt_hash(self->b_array[j]); + if (rehash == -1) { + goto fin; + } + + new_node->a_array[i] = hamt_node_assoc( + empty, shift + 5, + rehash, + self->b_array[j], + self->b_array[j + 1], + added_leaf); + + if (new_node->a_array[i] == NULL) { + goto fin; + } + } + j += 2; + } + } + + VALIDATE_ARRAY_NODE(new_node) + + /* That's it! */ + res = (PyHamtNode *)new_node; + + fin: + Py_XDECREF(empty); + if (res == NULL) { + Py_XDECREF(new_node); + } + return res; + } + else { + /* We have less than 16 keys at this level; let's just + create a new bitmap node out of this node with the + new key/val pair added. */ + + uint32_t key_idx = 2 * idx; + uint32_t val_idx = key_idx + 1; + Py_ssize_t i; + + *added_leaf = 1; + + /* Allocate new Bitmap node which can have one more key/val + pair in addition to what we have already. */ + PyHamtNode_Bitmap *new_node = + (PyHamtNode_Bitmap *)hamt_node_bitmap_new(2 * (n + 1)); + if (new_node == NULL) { + return NULL; + } + + /* Copy all keys/values that will be before the new key/value + we are adding. */ + for (i = 0; i < key_idx; i++) { + Py_XINCREF(self->b_array[i]); + new_node->b_array[i] = self->b_array[i]; + } + + /* Set the new key/value to the new Bitmap node. */ + Py_INCREF(key); + new_node->b_array[key_idx] = key; + Py_INCREF(val); + new_node->b_array[val_idx] = val; + + /* Copy all keys/values that will be after the new key/value + we are adding. */ + for (i = key_idx; i < Py_SIZE(self); i++) { + Py_XINCREF(self->b_array[i]); + new_node->b_array[i + 2] = self->b_array[i]; + } + + new_node->b_bitmap = self->b_bitmap | bit; + return (PyHamtNode *)new_node; + } + } +} + +static hamt_without_t +hamt_node_bitmap_without(PyHamtNode_Bitmap *self, + uint32_t shift, int32_t hash, + PyObject *key, + PyHamtNode **new_node) +{ + uint32_t bit = hamt_bitpos(hash, shift); + if ((self->b_bitmap & bit) == 0) { + return W_NOT_FOUND; + } + + uint32_t idx = hamt_bitindex(self->b_bitmap, bit); + + uint32_t key_idx = 2 * idx; + uint32_t val_idx = key_idx + 1; + + PyObject *key_or_null = self->b_array[key_idx]; + PyObject *val_or_node = self->b_array[val_idx]; + + if (key_or_null == NULL) { + /* key == NULL means that 'value' is another tree node. */ + + PyHamtNode *sub_node = NULL; + + hamt_without_t res = hamt_node_without( + (PyHamtNode *)val_or_node, + shift + 5, hash, key, &sub_node); + + switch (res) { + case W_EMPTY: + /* It's impossible for us to receive a W_EMPTY here: + + - Array nodes are converted to Bitmap nodes when + we delete 16th item from them; + + - Collision nodes are converted to Bitmap when + there is one item in them; + + - Bitmap node's without() inlines single-item + sub-nodes. + + So in no situation we can have a single-item + Bitmap child of another Bitmap node. + */ + Py_UNREACHABLE(); + + case W_NEWNODE: { + assert(sub_node != NULL); + + if (IS_BITMAP_NODE(sub_node)) { + PyHamtNode_Bitmap *sub_tree = (PyHamtNode_Bitmap *)sub_node; + if (hamt_node_bitmap_count(sub_tree) == 1 && + sub_tree->b_array[0] != NULL) + { + /* A bitmap node with one key/value pair. Just + merge it into this node. + + Note that we don't inline Bitmap nodes that + have a NULL key -- those nodes point to another + tree level, and we cannot simply move tree levels + up or down. + */ + + PyHamtNode_Bitmap *clone = hamt_node_bitmap_clone(self); + if (clone == NULL) { + Py_DECREF(sub_node); + return W_ERROR; + } + + PyObject *key = sub_tree->b_array[0]; + PyObject *val = sub_tree->b_array[1]; + + Py_INCREF(key); + Py_XSETREF(clone->b_array[key_idx], key); + Py_INCREF(val); + Py_SETREF(clone->b_array[val_idx], val); + + Py_DECREF(sub_tree); + + *new_node = (PyHamtNode *)clone; + return W_NEWNODE; + } + } + +#ifdef Py_DEBUG + /* Ensure that Collision.without implementation + converts to Bitmap nodes itself. + */ + if (IS_COLLISION_NODE(sub_node)) { + assert(hamt_node_collision_count( + (PyHamtNode_Collision*)sub_node) > 1); + } +#endif + + PyHamtNode_Bitmap *clone = hamt_node_bitmap_clone(self); + Py_SETREF(clone->b_array[val_idx], + (PyObject *)sub_node); /* borrow */ + + *new_node = (PyHamtNode *)clone; + return W_NEWNODE; + } + + case W_ERROR: + case W_NOT_FOUND: + assert(sub_node == NULL); + return res; + + default: + Py_UNREACHABLE(); + } + } + else { + /* We have a regular key/value pair */ + + int cmp = PyObject_RichCompareBool(key_or_null, key, Py_EQ); + if (cmp < 0) { + return W_ERROR; + } + if (cmp == 0) { + return W_NOT_FOUND; + } + + if (hamt_node_bitmap_count(self) == 1) { + return W_EMPTY; + } + + *new_node = (PyHamtNode *) + hamt_node_bitmap_clone_without(self, bit); + if (*new_node == NULL) { + return W_ERROR; + } + + return W_NEWNODE; + } +} + +static hamt_find_t +hamt_node_bitmap_find(PyHamtNode_Bitmap *self, + uint32_t shift, int32_t hash, + PyObject *key, PyObject **val) +{ + /* Lookup a key in a Bitmap node. */ + + uint32_t bit = hamt_bitpos(hash, shift); + uint32_t idx; + uint32_t key_idx; + uint32_t val_idx; + PyObject *key_or_null; + PyObject *val_or_node; + int comp_err; + + if ((self->b_bitmap & bit) == 0) { + return F_NOT_FOUND; + } + + idx = hamt_bitindex(self->b_bitmap, bit); + assert(idx >= 0); + key_idx = idx * 2; + val_idx = key_idx + 1; + + assert(val_idx < Py_SIZE(self)); + + key_or_null = self->b_array[key_idx]; + val_or_node = self->b_array[val_idx]; + + if (key_or_null == NULL) { + /* There are a few keys that have the same hash at the current shift + that match our key. Dispatch the lookup further down the tree. */ + assert(val_or_node != NULL); + return hamt_node_find((PyHamtNode *)val_or_node, + shift + 5, hash, key, val); + } + + /* We have only one key -- a potential match. Let's compare if the + key we are looking at is equal to the key we are looking for. */ + assert(key != NULL); + comp_err = PyObject_RichCompareBool(key, key_or_null, Py_EQ); + if (comp_err < 0) { /* exception in __eq__ */ + return F_ERROR; + } + if (comp_err == 1) { /* key == key_or_null */ + *val = val_or_node; + return F_FOUND; + } + + return F_NOT_FOUND; +} + +static int +hamt_node_bitmap_traverse(PyHamtNode_Bitmap *self, visitproc visit, void *arg) +{ + /* Bitmap's tp_traverse */ + + Py_ssize_t i; + + for (i = Py_SIZE(self); --i >= 0; ) { + Py_VISIT(self->b_array[i]); + } + + return 0; +} + +static void +hamt_node_bitmap_dealloc(PyHamtNode_Bitmap *self) +{ + /* Bitmap's tp_dealloc */ + + Py_ssize_t len = Py_SIZE(self); + Py_ssize_t i; + + PyObject_GC_UnTrack(self); + Py_TRASHCAN_SAFE_BEGIN(self) + + if (len > 0) { + i = len; + while (--i >= 0) { + Py_XDECREF(self->b_array[i]); + } + } + + Py_TYPE(self)->tp_free((PyObject *)self); + Py_TRASHCAN_SAFE_END(self) +} + +#ifdef Py_DEBUG +static int +hamt_node_bitmap_dump(PyHamtNode_Bitmap *node, + _PyUnicodeWriter *writer, int level) +{ + /* Debug build: __dump__() method implementation for Bitmap nodes. */ + + Py_ssize_t i; + PyObject *tmp1; + PyObject *tmp2; + + if (_hamt_dump_ident(writer, level + 1)) { + goto error; + } + + if (_hamt_dump_format(writer, "BitmapNode(size=%zd count=%zd ", + Py_SIZE(node), Py_SIZE(node) / 2)) + { + goto error; + } + + tmp1 = PyLong_FromUnsignedLong(node->b_bitmap); + if (tmp1 == NULL) { + goto error; + } + tmp2 = _PyLong_Format(tmp1, 2); + Py_DECREF(tmp1); + if (tmp2 == NULL) { + goto error; + } + if (_hamt_dump_format(writer, "bitmap=%S id=%p):\n", tmp2, node)) { + Py_DECREF(tmp2); + goto error; + } + Py_DECREF(tmp2); + + for (i = 0; i < Py_SIZE(node); i += 2) { + PyObject *key_or_null = node->b_array[i]; + PyObject *val_or_node = node->b_array[i + 1]; + + if (_hamt_dump_ident(writer, level + 2)) { + goto error; + } + + if (key_or_null == NULL) { + if (_hamt_dump_format(writer, "NULL:\n")) { + goto error; + } + + if (hamt_node_dump((PyHamtNode *)val_or_node, + writer, level + 2)) + { + goto error; + } + } + else { + if (_hamt_dump_format(writer, "%R: %R", key_or_null, + val_or_node)) + { + goto error; + } + } + + if (_hamt_dump_format(writer, "\n")) { + goto error; + } + } + + return 0; +error: + return -1; +} +#endif /* Py_DEBUG */ + + +/////////////////////////////////// Collision Node + + +static PyHamtNode * +hamt_node_collision_new(int32_t hash, Py_ssize_t size) +{ + /* Create a new Collision node. */ + + PyHamtNode_Collision *node; + Py_ssize_t i; + + assert(size >= 4); + assert(size % 2 == 0); + + node = PyObject_GC_NewVar( + PyHamtNode_Collision, &_PyHamt_CollisionNode_Type, size); + if (node == NULL) { + return NULL; + } + + for (i = 0; i < size; i++) { + node->c_array[i] = NULL; + } + + Py_SIZE(node) = size; + node->c_hash = hash; + + _PyObject_GC_TRACK(node); + + return (PyHamtNode *)node; +} + +static hamt_find_t +hamt_node_collision_find_index(PyHamtNode_Collision *self, PyObject *key, + Py_ssize_t *idx) +{ + /* Lookup `key` in the Collision node `self`. Set the index of the + found key to 'idx'. */ + + Py_ssize_t i; + PyObject *el; + + for (i = 0; i < Py_SIZE(self); i += 2) { + el = self->c_array[i]; + + assert(el != NULL); + int cmp = PyObject_RichCompareBool(key, el, Py_EQ); + if (cmp < 0) { + return F_ERROR; + } + if (cmp == 1) { + *idx = i; + return F_FOUND; + } + } + + return F_NOT_FOUND; +} + +static PyHamtNode * +hamt_node_collision_assoc(PyHamtNode_Collision *self, + uint32_t shift, int32_t hash, + PyObject *key, PyObject *val, int* added_leaf) +{ + /* Set a new key to this level (currently a Collision node) + of the tree. */ + + if (hash == self->c_hash) { + /* The hash of the 'key' we are adding matches the hash of + other keys in this Collision node. */ + + Py_ssize_t key_idx = -1; + hamt_find_t found; + PyHamtNode_Collision *new_node; + Py_ssize_t i; + + /* Let's try to lookup the new 'key', maybe we already have it. */ + found = hamt_node_collision_find_index(self, key, &key_idx); + switch (found) { + case F_ERROR: + /* Exception. */ + return NULL; + + case F_NOT_FOUND: + /* This is a totally new key. Clone the current node, + add a new key/value to the cloned node. */ + + new_node = (PyHamtNode_Collision *)hamt_node_collision_new( + self->c_hash, Py_SIZE(self) + 2); + if (new_node == NULL) { + return NULL; + } + + for (i = 0; i < Py_SIZE(self); i++) { + Py_INCREF(self->c_array[i]); + new_node->c_array[i] = self->c_array[i]; + } + + Py_INCREF(key); + new_node->c_array[i] = key; + Py_INCREF(val); + new_node->c_array[i + 1] = val; + + *added_leaf = 1; + return (PyHamtNode *)new_node; + + case F_FOUND: + /* There's a key which is equal to the key we are adding. */ + + assert(key_idx >= 0); + assert(key_idx < Py_SIZE(self)); + Py_ssize_t val_idx = key_idx + 1; + + if (self->c_array[val_idx] == val) { + /* We're setting a key/value pair that's already set. */ + Py_INCREF(self); + return (PyHamtNode *)self; + } + + /* We need to replace old value for the key + with a new value. Create a new Collision node.*/ + new_node = (PyHamtNode_Collision *)hamt_node_collision_new( + self->c_hash, Py_SIZE(self)); + if (new_node == NULL) { + return NULL; + } + + /* Copy all elements of the old node to the new one. */ + for (i = 0; i < Py_SIZE(self); i++) { + Py_INCREF(self->c_array[i]); + new_node->c_array[i] = self->c_array[i]; + } + + /* Replace the old value with the new value for the our key. */ + Py_DECREF(new_node->c_array[val_idx]); + Py_INCREF(val); + new_node->c_array[val_idx] = val; + + return (PyHamtNode *)new_node; + + default: + Py_UNREACHABLE(); + } + } + else { + /* The hash of the new key is different from the hash that + all keys of this Collision node have. + + Create a Bitmap node inplace with two children: + key/value pair that we're adding, and the Collision node + we're replacing on this tree level. + */ + + PyHamtNode_Bitmap *new_node; + PyHamtNode *assoc_res; + + new_node = (PyHamtNode_Bitmap *)hamt_node_bitmap_new(2); + if (new_node == NULL) { + return NULL; + } + new_node->b_bitmap = hamt_bitpos(self->c_hash, shift); + Py_INCREF(self); + new_node->b_array[1] = (PyObject*) self; + + assoc_res = hamt_node_bitmap_assoc( + new_node, shift, hash, key, val, added_leaf); + Py_DECREF(new_node); + return assoc_res; + } +} + +static inline Py_ssize_t +hamt_node_collision_count(PyHamtNode_Collision *node) +{ + return Py_SIZE(node) / 2; +} + +static hamt_without_t +hamt_node_collision_without(PyHamtNode_Collision *self, + uint32_t shift, int32_t hash, + PyObject *key, + PyHamtNode **new_node) +{ + if (hash != self->c_hash) { + return W_NOT_FOUND; + } + + Py_ssize_t key_idx = -1; + hamt_find_t found = hamt_node_collision_find_index(self, key, &key_idx); + + switch (found) { + case F_ERROR: + return W_ERROR; + + case F_NOT_FOUND: + return W_NOT_FOUND; + + case F_FOUND: + assert(key_idx >= 0); + assert(key_idx < Py_SIZE(self)); + + Py_ssize_t new_count = hamt_node_collision_count(self) - 1; + + if (new_count == 0) { + /* The node has only one key/value pair and it's for the + key we're trying to delete. So a new node will be empty + after the removal. + */ + return W_EMPTY; + } + + if (new_count == 1) { + /* The node has two keys, and after deletion the + new Collision node would have one. Collision nodes + with one key shouldn't exist, co convert it to a + Bitmap node. + */ + PyHamtNode_Bitmap *node = (PyHamtNode_Bitmap *) + hamt_node_bitmap_new(2); + if (node == NULL) { + return W_ERROR; + } + + if (key_idx == 0) { + Py_INCREF(self->c_array[2]); + node->b_array[0] = self->c_array[2]; + Py_INCREF(self->c_array[3]); + node->b_array[1] = self->c_array[3]; + } + else { + assert(key_idx == 2); + Py_INCREF(self->c_array[0]); + node->b_array[0] = self->c_array[0]; + Py_INCREF(self->c_array[1]); + node->b_array[1] = self->c_array[1]; + } + + node->b_bitmap = hamt_bitpos(hash, shift); + + *new_node = (PyHamtNode *)node; + return W_NEWNODE; + } + + /* Allocate a new Collision node with capacity for one + less key/value pair */ + PyHamtNode_Collision *new = (PyHamtNode_Collision *) + hamt_node_collision_new( + self->c_hash, Py_SIZE(self) - 2); + + /* Copy all other keys from `self` to `new` */ + Py_ssize_t i; + for (i = 0; i < key_idx; i++) { + Py_INCREF(self->c_array[i]); + new->c_array[i] = self->c_array[i]; + } + for (i = key_idx + 2; i < Py_SIZE(self); i++) { + Py_INCREF(self->c_array[i]); + new->c_array[i - 2] = self->c_array[i]; + } + + *new_node = (PyHamtNode*)new; + return W_NEWNODE; + + default: + Py_UNREACHABLE(); + } +} + +static hamt_find_t +hamt_node_collision_find(PyHamtNode_Collision *self, + uint32_t shift, int32_t hash, + PyObject *key, PyObject **val) +{ + /* Lookup `key` in the Collision node `self`. Set the value + for the found key to 'val'. */ + + Py_ssize_t idx = -1; + hamt_find_t res; + + res = hamt_node_collision_find_index(self, key, &idx); + if (res == F_ERROR || res == F_NOT_FOUND) { + return res; + } + + assert(idx >= 0); + assert(idx + 1 < Py_SIZE(self)); + + *val = self->c_array[idx + 1]; + assert(*val != NULL); + + return F_FOUND; +} + + +static int +hamt_node_collision_traverse(PyHamtNode_Collision *self, + visitproc visit, void *arg) +{ + /* Collision's tp_traverse */ + + Py_ssize_t i; + + for (i = Py_SIZE(self); --i >= 0; ) { + Py_VISIT(self->c_array[i]); + } + + return 0; +} + +static void +hamt_node_collision_dealloc(PyHamtNode_Collision *self) +{ + /* Collision's tp_dealloc */ + + Py_ssize_t len = Py_SIZE(self); + + PyObject_GC_UnTrack(self); + Py_TRASHCAN_SAFE_BEGIN(self) + + if (len > 0) { + + while (--len >= 0) { + Py_XDECREF(self->c_array[len]); + } + } + + Py_TYPE(self)->tp_free((PyObject *)self); + Py_TRASHCAN_SAFE_END(self) +} + +#ifdef Py_DEBUG +static int +hamt_node_collision_dump(PyHamtNode_Collision *node, + _PyUnicodeWriter *writer, int level) +{ + /* Debug build: __dump__() method implementation for Collision nodes. */ + + Py_ssize_t i; + + if (_hamt_dump_ident(writer, level + 1)) { + goto error; + } + + if (_hamt_dump_format(writer, "CollisionNode(size=%zd id=%p):\n", + Py_SIZE(node), node)) + { + goto error; + } + + for (i = 0; i < Py_SIZE(node); i += 2) { + PyObject *key = node->c_array[i]; + PyObject *val = node->c_array[i + 1]; + + if (_hamt_dump_ident(writer, level + 2)) { + goto error; + } + + if (_hamt_dump_format(writer, "%R: %R\n", key, val)) { + goto error; + } + } + + return 0; +error: + return -1; +} +#endif /* Py_DEBUG */ + + +/////////////////////////////////// Array Node + + +static PyHamtNode * +hamt_node_array_new(Py_ssize_t count) +{ + Py_ssize_t i; + + PyHamtNode_Array *node = PyObject_GC_New( + PyHamtNode_Array, &_PyHamt_ArrayNode_Type); + if (node == NULL) { + return NULL; + } + + for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + node->a_array[i] = NULL; + } + + node->a_count = count; + + _PyObject_GC_TRACK(node); + return (PyHamtNode *)node; +} + +static PyHamtNode_Array * +hamt_node_array_clone(PyHamtNode_Array *node) +{ + PyHamtNode_Array *clone; + Py_ssize_t i; + + VALIDATE_ARRAY_NODE(node) + + /* Create a new Array node. */ + clone = (PyHamtNode_Array *)hamt_node_array_new(node->a_count); + if (clone == NULL) { + return NULL; + } + + /* Copy all elements from the current Array node to the new one. */ + for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + Py_XINCREF(node->a_array[i]); + clone->a_array[i] = node->a_array[i]; + } + + VALIDATE_ARRAY_NODE(clone) + return clone; +} + +static PyHamtNode * +hamt_node_array_assoc(PyHamtNode_Array *self, + uint32_t shift, int32_t hash, + PyObject *key, PyObject *val, int* added_leaf) +{ + /* Set a new key to this level (currently a Collision node) + of the tree. + + Array nodes don't store values, they can only point to + other nodes. They are simple arrays of 32 BaseNode pointers/ + */ + + uint32_t idx = hamt_mask(hash, shift); + PyHamtNode *node = self->a_array[idx]; + PyHamtNode *child_node; + PyHamtNode_Array *new_node; + Py_ssize_t i; + + if (node == NULL) { + /* There's no child node for the given hash. Create a new + Bitmap node for this key. */ + + PyHamtNode_Bitmap *empty = NULL; + + /* Get an empty Bitmap node to work with. */ + empty = (PyHamtNode_Bitmap *)hamt_node_bitmap_new(0); + if (empty == NULL) { + return NULL; + } + + /* Set key/val to the newly created empty Bitmap, thus + creating a new Bitmap node with our key/value pair. */ + child_node = hamt_node_bitmap_assoc( + empty, + shift + 5, hash, key, val, added_leaf); + Py_DECREF(empty); + if (child_node == NULL) { + return NULL; + } + + /* Create a new Array node. */ + new_node = (PyHamtNode_Array *)hamt_node_array_new(self->a_count + 1); + if (new_node == NULL) { + Py_DECREF(child_node); + return NULL; + } + + /* Copy all elements from the current Array node to the + new one. */ + for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + Py_XINCREF(self->a_array[i]); + new_node->a_array[i] = self->a_array[i]; + } + + assert(new_node->a_array[idx] == NULL); + new_node->a_array[idx] = child_node; /* borrow */ + VALIDATE_ARRAY_NODE(new_node) + } + else { + /* There's a child node for the given hash. + Set the key to it./ */ + child_node = hamt_node_assoc( + node, shift + 5, hash, key, val, added_leaf); + if (child_node == (PyHamtNode *)self) { + Py_DECREF(child_node); + return (PyHamtNode *)self; + } + + new_node = hamt_node_array_clone(self); + if (new_node == NULL) { + Py_DECREF(child_node); + return NULL; + } + + Py_SETREF(new_node->a_array[idx], child_node); /* borrow */ + VALIDATE_ARRAY_NODE(new_node) + } + + return (PyHamtNode *)new_node; +} + +static hamt_without_t +hamt_node_array_without(PyHamtNode_Array *self, + uint32_t shift, int32_t hash, + PyObject *key, + PyHamtNode **new_node) +{ + uint32_t idx = hamt_mask(hash, shift); + PyHamtNode *node = self->a_array[idx]; + + if (node == NULL) { + return W_NOT_FOUND; + } + + PyHamtNode *sub_node = NULL; + hamt_without_t res = hamt_node_without( + (PyHamtNode *)node, + shift + 5, hash, key, &sub_node); + + switch (res) { + case W_NOT_FOUND: + case W_ERROR: + assert(sub_node == NULL); + return res; + + case W_NEWNODE: { + /* We need to replace a node at the `idx` index. + Clone this node and replace. + */ + assert(sub_node != NULL); + + PyHamtNode_Array *clone = hamt_node_array_clone(self); + if (clone == NULL) { + Py_DECREF(sub_node); + return W_ERROR; + } + + Py_SETREF(clone->a_array[idx], sub_node); /* borrow */ + *new_node = (PyHamtNode*)clone; /* borrow */ + return W_NEWNODE; + } + + case W_EMPTY: { + assert(sub_node == NULL); + /* We need to remove a node at the `idx` index. + Calculate the size of the replacement Array node. + */ + Py_ssize_t new_count = self->a_count - 1; + + if (new_count == 0) { + return W_EMPTY; + } + + if (new_count >= 16) { + /* We convert Bitmap nodes to Array nodes, when a + Bitmap node needs to store more than 15 key/value + pairs. So we will create a new Array node if we + the number of key/values after deletion is still + greater than 15. + */ + + PyHamtNode_Array *new = hamt_node_array_clone(self); + if (new == NULL) { + return W_ERROR; + } + new->a_count = new_count; + Py_CLEAR(new->a_array[idx]); + + *new_node = (PyHamtNode*)new; /* borrow */ + return W_NEWNODE; + } + + /* New Array node would have less than 16 key/value + pairs. We need to create a replacement Bitmap node. */ + + Py_ssize_t bitmap_size = new_count * 2; + uint32_t bitmap = 0; + + PyHamtNode_Bitmap *new = (PyHamtNode_Bitmap *) + hamt_node_bitmap_new(bitmap_size); + if (new == NULL) { + return W_ERROR; + } + + Py_ssize_t new_i = 0; + for (uint32_t i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + if (i == idx) { + /* Skip the node we are deleting. */ + continue; + } + + PyHamtNode *node = self->a_array[i]; + if (node == NULL) { + /* Skip any missing nodes. */ + continue; + } + + bitmap |= 1 << i; + + if (IS_BITMAP_NODE(node)) { + PyHamtNode_Bitmap *child = (PyHamtNode_Bitmap *)node; + + if (hamt_node_bitmap_count(child) == 1 && + child->b_array[0] != NULL) + { + /* node is a Bitmap with one key/value pair, just + merge it into the new Bitmap node we're building. + + Note that we don't inline Bitmap nodes that + have a NULL key -- those nodes point to another + tree level, and we cannot simply move tree levels + up or down. + */ + PyObject *key = child->b_array[0]; + PyObject *val = child->b_array[1]; + + Py_INCREF(key); + new->b_array[new_i] = key; + Py_INCREF(val); + new->b_array[new_i + 1] = val; + } + else { + new->b_array[new_i] = NULL; + Py_INCREF(node); + new->b_array[new_i + 1] = (PyObject*)node; + } + } + else { + +#ifdef Py_DEBUG + if (IS_COLLISION_NODE(node)) { + Py_ssize_t child_count = hamt_node_collision_count( + (PyHamtNode_Collision*)node); + assert(child_count > 1); + } + else if (IS_ARRAY_NODE(node)) { + assert(((PyHamtNode_Array*)node)->a_count >= 16); + } +#endif + + /* Just copy the node into our new Bitmap */ + new->b_array[new_i] = NULL; + Py_INCREF(node); + new->b_array[new_i + 1] = (PyObject*)node; + } + + new_i += 2; + } + + new->b_bitmap = bitmap; + *new_node = (PyHamtNode*)new; /* borrow */ + return W_NEWNODE; + } + + default: + Py_UNREACHABLE(); + } +} + +static hamt_find_t +hamt_node_array_find(PyHamtNode_Array *self, + uint32_t shift, int32_t hash, + PyObject *key, PyObject **val) +{ + /* Lookup `key` in the Array node `self`. Set the value + for the found key to 'val'. */ + + uint32_t idx = hamt_mask(hash, shift); + PyHamtNode *node; + + node = self->a_array[idx]; + if (node == NULL) { + return F_NOT_FOUND; + } + + /* Dispatch to the generic hamt_node_find */ + return hamt_node_find(node, shift + 5, hash, key, val); +} + +static int +hamt_node_array_traverse(PyHamtNode_Array *self, + visitproc visit, void *arg) +{ + /* Array's tp_traverse */ + + Py_ssize_t i; + + for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + Py_VISIT(self->a_array[i]); + } + + return 0; +} + +static void +hamt_node_array_dealloc(PyHamtNode_Array *self) +{ + /* Array's tp_dealloc */ + + Py_ssize_t i; + + PyObject_GC_UnTrack(self); + Py_TRASHCAN_SAFE_BEGIN(self) + + for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + Py_XDECREF(self->a_array[i]); + } + + Py_TYPE(self)->tp_free((PyObject *)self); + Py_TRASHCAN_SAFE_END(self) +} + +#ifdef Py_DEBUG +static int +hamt_node_array_dump(PyHamtNode_Array *node, + _PyUnicodeWriter *writer, int level) +{ + /* Debug build: __dump__() method implementation for Array nodes. */ + + Py_ssize_t i; + + if (_hamt_dump_ident(writer, level + 1)) { + goto error; + } + + if (_hamt_dump_format(writer, "ArrayNode(id=%p):\n", node)) { + goto error; + } + + for (i = 0; i < HAMT_ARRAY_NODE_SIZE; i++) { + if (node->a_array[i] == NULL) { + continue; + } + + if (_hamt_dump_ident(writer, level + 2)) { + goto error; + } + + if (_hamt_dump_format(writer, "%d::\n", i)) { + goto error; + } + + if (hamt_node_dump(node->a_array[i], writer, level + 1)) { + goto error; + } + + if (_hamt_dump_format(writer, "\n")) { + goto error; + } + } + + return 0; +error: + return -1; +} +#endif /* Py_DEBUG */ + + +/////////////////////////////////// Node Dispatch + + +static PyHamtNode * +hamt_node_assoc(PyHamtNode *node, + uint32_t shift, int32_t hash, + PyObject *key, PyObject *val, int* added_leaf) +{ + /* Set key/value to the 'node' starting with the given shift/hash. + Return a new node, or the same node if key/value already + set. + + added_leaf will be set to 1 if key/value wasn't in the + tree before. + + This method automatically dispatches to the suitable + hamt_node_{nodetype}_assoc method. + */ + + if (IS_BITMAP_NODE(node)) { + return hamt_node_bitmap_assoc( + (PyHamtNode_Bitmap *)node, + shift, hash, key, val, added_leaf); + } + else if (IS_ARRAY_NODE(node)) { + return hamt_node_array_assoc( + (PyHamtNode_Array *)node, + shift, hash, key, val, added_leaf); + } + else { + assert(IS_COLLISION_NODE(node)); + return hamt_node_collision_assoc( + (PyHamtNode_Collision *)node, + shift, hash, key, val, added_leaf); + } +} + +static hamt_without_t +hamt_node_without(PyHamtNode *node, + uint32_t shift, int32_t hash, + PyObject *key, + PyHamtNode **new_node) +{ + if (IS_BITMAP_NODE(node)) { + return hamt_node_bitmap_without( + (PyHamtNode_Bitmap *)node, + shift, hash, key, + new_node); + } + else if (IS_ARRAY_NODE(node)) { + return hamt_node_array_without( + (PyHamtNode_Array *)node, + shift, hash, key, + new_node); + } + else { + assert(IS_COLLISION_NODE(node)); + return hamt_node_collision_without( + (PyHamtNode_Collision *)node, + shift, hash, key, + new_node); + } +} + +static hamt_find_t +hamt_node_find(PyHamtNode *node, + uint32_t shift, int32_t hash, + PyObject *key, PyObject **val) +{ + /* Find the key in the node starting with the given shift/hash. + + If a value is found, the result will be set to F_FOUND, and + *val will point to the found value object. + + If a value wasn't found, the result will be set to F_NOT_FOUND. + + If an exception occurs during the call, the result will be F_ERROR. + + This method automatically dispatches to the suitable + hamt_node_{nodetype}_find method. + */ + + if (IS_BITMAP_NODE(node)) { + return hamt_node_bitmap_find( + (PyHamtNode_Bitmap *)node, + shift, hash, key, val); + + } + else if (IS_ARRAY_NODE(node)) { + return hamt_node_array_find( + (PyHamtNode_Array *)node, + shift, hash, key, val); + } + else { + assert(IS_COLLISION_NODE(node)); + return hamt_node_collision_find( + (PyHamtNode_Collision *)node, + shift, hash, key, val); + } +} + +#ifdef Py_DEBUG +static int +hamt_node_dump(PyHamtNode *node, + _PyUnicodeWriter *writer, int level) +{ + /* Debug build: __dump__() method implementation for a node. + + This method automatically dispatches to the suitable + hamt_node_{nodetype})_dump method. + */ + + if (IS_BITMAP_NODE(node)) { + return hamt_node_bitmap_dump( + (PyHamtNode_Bitmap *)node, writer, level); + } + else if (IS_ARRAY_NODE(node)) { + return hamt_node_array_dump( + (PyHamtNode_Array *)node, writer, level); + } + else { + assert(IS_COLLISION_NODE(node)); + return hamt_node_collision_dump( + (PyHamtNode_Collision *)node, writer, level); + } +} +#endif /* Py_DEBUG */ + + +/////////////////////////////////// Iterators: Machinery + + +static hamt_iter_t +hamt_iterator_next(PyHamtIteratorState *iter, PyObject **key, PyObject **val); + + +static void +hamt_iterator_init(PyHamtIteratorState *iter, PyHamtNode *root) +{ + for (uint32_t i = 0; i < _Py_HAMT_MAX_TREE_DEPTH; i++) { + iter->i_nodes[i] = NULL; + iter->i_pos[i] = 0; + } + + iter->i_level = 0; + + /* Note: we don't incref/decref nodes in i_nodes. */ + iter->i_nodes[0] = root; +} + +static hamt_iter_t +hamt_iterator_bitmap_next(PyHamtIteratorState *iter, + PyObject **key, PyObject **val) +{ + int8_t level = iter->i_level; + + PyHamtNode_Bitmap *node = (PyHamtNode_Bitmap *)(iter->i_nodes[level]); + Py_ssize_t pos = iter->i_pos[level]; + + if (pos + 1 >= Py_SIZE(node)) { +#ifdef Py_DEBUG + assert(iter->i_level >= 0); + iter->i_nodes[iter->i_level] = NULL; +#endif + iter->i_level--; + return hamt_iterator_next(iter, key, val); + } + + if (node->b_array[pos] == NULL) { + iter->i_pos[level] = pos + 2; + + int8_t next_level = level + 1; + assert(next_level < _Py_HAMT_MAX_TREE_DEPTH); + iter->i_level = next_level; + iter->i_pos[next_level] = 0; + iter->i_nodes[next_level] = (PyHamtNode *) + node->b_array[pos + 1]; + + return hamt_iterator_next(iter, key, val); + } + + *key = node->b_array[pos]; + *val = node->b_array[pos + 1]; + iter->i_pos[level] = pos + 2; + return I_ITEM; +} + +static hamt_iter_t +hamt_iterator_collision_next(PyHamtIteratorState *iter, + PyObject **key, PyObject **val) +{ + int8_t level = iter->i_level; + + PyHamtNode_Collision *node = (PyHamtNode_Collision *)(iter->i_nodes[level]); + Py_ssize_t pos = iter->i_pos[level]; + + if (pos + 1 >= Py_SIZE(node)) { +#ifdef Py_DEBUG + assert(iter->i_level >= 0); + iter->i_nodes[iter->i_level] = NULL; +#endif + iter->i_level--; + return hamt_iterator_next(iter, key, val); + } + + *key = node->c_array[pos]; + *val = node->c_array[pos + 1]; + iter->i_pos[level] = pos + 2; + return I_ITEM; +} + +static hamt_iter_t +hamt_iterator_array_next(PyHamtIteratorState *iter, + PyObject **key, PyObject **val) +{ + int8_t level = iter->i_level; + + PyHamtNode_Array *node = (PyHamtNode_Array *)(iter->i_nodes[level]); + Py_ssize_t pos = iter->i_pos[level]; + + if (pos >= HAMT_ARRAY_NODE_SIZE) { +#ifdef Py_DEBUG + assert(iter->i_level >= 0); + iter->i_nodes[iter->i_level] = NULL; +#endif + iter->i_level--; + return hamt_iterator_next(iter, key, val); + } + + for (Py_ssize_t i = pos; i < HAMT_ARRAY_NODE_SIZE; i++) { + if (node->a_array[i] != NULL) { + iter->i_pos[level] = i + 1; + + int8_t next_level = level + 1; + assert(next_level < _Py_HAMT_MAX_TREE_DEPTH); + iter->i_pos[next_level] = 0; + iter->i_nodes[next_level] = node->a_array[i]; + iter->i_level = next_level; + + return hamt_iterator_next(iter, key, val); + } + } + +#ifdef Py_DEBUG + assert(iter->i_level >= 0); + iter->i_nodes[iter->i_level] = NULL; +#endif + + iter->i_level--; + return hamt_iterator_next(iter, key, val); +} + +static hamt_iter_t +hamt_iterator_next(PyHamtIteratorState *iter, PyObject **key, PyObject **val) +{ + if (iter->i_level < 0) { + return I_END; + } + + assert(iter->i_level < _Py_HAMT_MAX_TREE_DEPTH); + + PyHamtNode *current = iter->i_nodes[iter->i_level]; + + if (IS_BITMAP_NODE(current)) { + return hamt_iterator_bitmap_next(iter, key, val); + } + else if (IS_ARRAY_NODE(current)) { + return hamt_iterator_array_next(iter, key, val); + } + else { + assert(IS_COLLISION_NODE(current)); + return hamt_iterator_collision_next(iter, key, val); + } +} + + +/////////////////////////////////// HAMT high-level functions + + +PyHamtObject * +_PyHamt_Assoc(PyHamtObject *o, PyObject *key, PyObject *val) +{ + int32_t key_hash; + int added_leaf = 0; + PyHamtNode *new_root; + PyHamtObject *new_o; + + key_hash = hamt_hash(key); + if (key_hash == -1) { + return NULL; + } + + new_root = hamt_node_assoc( + (PyHamtNode *)(o->h_root), + 0, key_hash, key, val, &added_leaf); + if (new_root == NULL) { + return NULL; + } + + if (new_root == o->h_root) { + Py_DECREF(new_root); + Py_INCREF(o); + return o; + } + + new_o = hamt_alloc(); + if (new_o == NULL) { + Py_DECREF(new_root); + return NULL; + } + + new_o->h_root = new_root; /* borrow */ + new_o->h_count = added_leaf ? o->h_count + 1 : o->h_count; + + return new_o; +} + +PyHamtObject * +_PyHamt_Without(PyHamtObject *o, PyObject *key) +{ + int32_t key_hash = hamt_hash(key); + if (key_hash == -1) { + return NULL; + } + + PyHamtNode *new_root; + + hamt_without_t res = hamt_node_without( + (PyHamtNode *)(o->h_root), + 0, key_hash, key, + &new_root); + + switch (res) { + case W_ERROR: + return NULL; + case W_EMPTY: + return _PyHamt_New(); + case W_NOT_FOUND: + Py_INCREF(o); + return o; + case W_NEWNODE: { + PyHamtObject *new_o = hamt_alloc(); + if (new_o == NULL) { + Py_DECREF(new_root); + return NULL; + } + + new_o->h_root = new_root; /* borrow */ + new_o->h_count = o->h_count - 1; + assert(new_o->h_count >= 0); + return new_o; + } + default: + Py_UNREACHABLE(); + } +} + +static hamt_find_t +hamt_find(PyHamtObject *o, PyObject *key, PyObject **val) +{ + if (o->h_count == 0) { + return F_NOT_FOUND; + } + + int32_t key_hash = hamt_hash(key); + if (key_hash == -1) { + return F_ERROR; + } + + return hamt_node_find(o->h_root, 0, key_hash, key, val); +} + + +int +_PyHamt_Find(PyHamtObject *o, PyObject *key, PyObject **val) +{ + hamt_find_t res = hamt_find(o, key, val); + switch (res) { + case F_ERROR: + return -1; + case F_NOT_FOUND: + return 0; + case F_FOUND: + return 1; + default: + Py_UNREACHABLE(); + } +} + + +int +_PyHamt_Eq(PyHamtObject *v, PyHamtObject *w) +{ + if (v == w) { + return 1; + } + + if (v->h_count != w->h_count) { + return 0; + } + + PyHamtIteratorState iter; + hamt_iter_t iter_res; + hamt_find_t find_res; + PyObject *v_key; + PyObject *v_val; + PyObject *w_val; + + hamt_iterator_init(&iter, v->h_root); + + do { + iter_res = hamt_iterator_next(&iter, &v_key, &v_val); + if (iter_res == I_ITEM) { + find_res = hamt_find(w, v_key, &w_val); + switch (find_res) { + case F_ERROR: + return -1; + + case F_NOT_FOUND: + return 0; + + case F_FOUND: { + int cmp = PyObject_RichCompareBool(v_val, w_val, Py_EQ); + if (cmp < 0) { + return -1; + } + if (cmp == 0) { + return 0; + } + } + } + } + } while (iter_res != I_END); + + return 1; +} + +Py_ssize_t +_PyHamt_Len(PyHamtObject *o) +{ + return o->h_count; +} + +static PyHamtObject * +hamt_alloc(void) +{ + PyHamtObject *o; + o = PyObject_GC_New(PyHamtObject, &_PyHamt_Type); + if (o == NULL) { + return NULL; + } + o->h_weakreflist = NULL; + PyObject_GC_Track(o); + return o; +} + +PyHamtObject * +_PyHamt_New(void) +{ + if (_empty_hamt != NULL) { + /* HAMT is an immutable object so we can easily cache an + empty instance. */ + Py_INCREF(_empty_hamt); + return _empty_hamt; + } + + PyHamtObject *o = hamt_alloc(); + if (o == NULL) { + return NULL; + } + + o->h_root = hamt_node_bitmap_new(0); + if (o->h_root == NULL) { + Py_DECREF(o); + return NULL; + } + + o->h_count = 0; + + if (_empty_hamt == NULL) { + Py_INCREF(o); + _empty_hamt = o; + } + + return o; +} + +#ifdef Py_DEBUG +static PyObject * +hamt_dump(PyHamtObject *self) +{ + _PyUnicodeWriter writer; + + _PyUnicodeWriter_Init(&writer); + + if (_hamt_dump_format(&writer, "HAMT(len=%zd):\n", self->h_count)) { + goto error; + } + + if (hamt_node_dump(self->h_root, &writer, 0)) { + goto error; + } + + return _PyUnicodeWriter_Finish(&writer); + +error: + _PyUnicodeWriter_Dealloc(&writer); + return NULL; +} +#endif /* Py_DEBUG */ + + +/////////////////////////////////// Iterators: Shared Iterator Implementation + + +static int +hamt_baseiter_tp_clear(PyHamtIterator *it) +{ + Py_CLEAR(it->hi_obj); + return 0; +} + +static void +hamt_baseiter_tp_dealloc(PyHamtIterator *it) +{ + PyObject_GC_UnTrack(it); + (void)hamt_baseiter_tp_clear(it); + PyObject_GC_Del(it); +} + +static int +hamt_baseiter_tp_traverse(PyHamtIterator *it, visitproc visit, void *arg) +{ + Py_VISIT(it->hi_obj); + return 0; +} + +static PyObject * +hamt_baseiter_tp_iternext(PyHamtIterator *it) +{ + PyObject *key; + PyObject *val; + hamt_iter_t res = hamt_iterator_next(&it->hi_iter, &key, &val); + + switch (res) { + case I_END: + PyErr_SetNone(PyExc_StopIteration); + return NULL; + + case I_ITEM: { + return (*(it->hi_yield))(key, val); + } + + default: { + Py_UNREACHABLE(); + } + } +} + +static Py_ssize_t +hamt_baseiter_tp_len(PyHamtIterator *it) +{ + return it->hi_obj->h_count; +} + +static PyMappingMethods PyHamtIterator_as_mapping = { + (lenfunc)hamt_baseiter_tp_len, +}; + +static PyObject * +hamt_baseiter_new(PyTypeObject *type, binaryfunc yield, PyHamtObject *o) +{ + PyHamtIterator *it = PyObject_GC_New(PyHamtIterator, type); + if (it == NULL) { + return NULL; + } + + Py_INCREF(o); + it->hi_obj = o; + it->hi_yield = yield; + + hamt_iterator_init(&it->hi_iter, o->h_root); + + return (PyObject*)it; +} + +#define ITERATOR_TYPE_SHARED_SLOTS \ + .tp_basicsize = sizeof(PyHamtIterator), \ + .tp_itemsize = 0, \ + .tp_as_mapping = &PyHamtIterator_as_mapping, \ + .tp_dealloc = (destructor)hamt_baseiter_tp_dealloc, \ + .tp_getattro = PyObject_GenericGetAttr, \ + .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, \ + .tp_traverse = (traverseproc)hamt_baseiter_tp_traverse, \ + .tp_clear = (inquiry)hamt_baseiter_tp_clear, \ + .tp_iter = PyObject_SelfIter, \ + .tp_iternext = (iternextfunc)hamt_baseiter_tp_iternext, + + +/////////////////////////////////// _PyHamtItems_Type + + +PyTypeObject _PyHamtItems_Type = { + PyVarObject_HEAD_INIT(NULL, 0) + "items", + ITERATOR_TYPE_SHARED_SLOTS +}; + +static PyObject * +hamt_iter_yield_items(PyObject *key, PyObject *val) +{ + return PyTuple_Pack(2, key, val); +} + +PyObject * +_PyHamt_NewIterItems(PyHamtObject *o) +{ + return hamt_baseiter_new( + &_PyHamtItems_Type, hamt_iter_yield_items, o); +} + + +/////////////////////////////////// _PyHamtKeys_Type + + +PyTypeObject _PyHamtKeys_Type = { + PyVarObject_HEAD_INIT(NULL, 0) + "keys", + ITERATOR_TYPE_SHARED_SLOTS +}; + +static PyObject * +hamt_iter_yield_keys(PyObject *key, PyObject *val) +{ + Py_INCREF(key); + return key; +} + +PyObject * +_PyHamt_NewIterKeys(PyHamtObject *o) +{ + return hamt_baseiter_new( + &_PyHamtKeys_Type, hamt_iter_yield_keys, o); +} + + +/////////////////////////////////// _PyHamtValues_Type + + +PyTypeObject _PyHamtValues_Type = { + PyVarObject_HEAD_INIT(NULL, 0) + "values", + ITERATOR_TYPE_SHARED_SLOTS +}; + +static PyObject * +hamt_iter_yield_values(PyObject *key, PyObject *val) +{ + Py_INCREF(val); + return val; +} + +PyObject * +_PyHamt_NewIterValues(PyHamtObject *o) +{ + return hamt_baseiter_new( + &_PyHamtValues_Type, hamt_iter_yield_values, o); +} + + +/////////////////////////////////// _PyHamt_Type + + +#ifdef Py_DEBUG +static PyObject * +hamt_dump(PyHamtObject *self); +#endif + + +static PyObject * +hamt_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds) +{ + return (PyObject*)_PyHamt_New(); +} + +static int +hamt_tp_clear(PyHamtObject *self) +{ + Py_CLEAR(self->h_root); + return 0; +} + + +static int +hamt_tp_traverse(PyHamtObject *self, visitproc visit, void *arg) +{ + Py_VISIT(self->h_root); + return 0; +} + +static void +hamt_tp_dealloc(PyHamtObject *self) +{ + PyObject_GC_UnTrack(self); + if (self->h_weakreflist != NULL) { + PyObject_ClearWeakRefs((PyObject*)self); + } + (void)hamt_tp_clear(self); + Py_TYPE(self)->tp_free(self); +} + + +static PyObject * +hamt_tp_richcompare(PyObject *v, PyObject *w, int op) +{ + if (!PyHamt_Check(v) || !PyHamt_Check(w) || (op != Py_EQ && op != Py_NE)) { + Py_RETURN_NOTIMPLEMENTED; + } + + int res = _PyHamt_Eq((PyHamtObject *)v, (PyHamtObject *)w); + if (res < 0) { + return NULL; + } + + if (op == Py_NE) { + res = !res; + } + + if (res) { + Py_RETURN_TRUE; + } + else { + Py_RETURN_FALSE; + } +} + +static int +hamt_tp_contains(PyHamtObject *self, PyObject *key) +{ + PyObject *val; + return _PyHamt_Find(self, key, &val); +} + +static PyObject * +hamt_tp_subscript(PyHamtObject *self, PyObject *key) +{ + PyObject *val; + hamt_find_t res = hamt_find(self, key, &val); + switch (res) { + case F_ERROR: + return NULL; + case F_FOUND: + Py_INCREF(val); + return val; + case F_NOT_FOUND: + PyErr_SetObject(PyExc_KeyError, key); + return NULL; + default: + Py_UNREACHABLE(); + } +} + +static Py_ssize_t +hamt_tp_len(PyHamtObject *self) +{ + return _PyHamt_Len(self); +} + +static PyObject * +hamt_tp_iter(PyHamtObject *self) +{ + return _PyHamt_NewIterKeys(self); +} + +static PyObject * +hamt_py_set(PyHamtObject *self, PyObject *args) +{ + PyObject *key; + PyObject *val; + + if (!PyArg_UnpackTuple(args, "set", 2, 2, &key, &val)) { + return NULL; + } + + return (PyObject *)_PyHamt_Assoc(self, key, val); +} + +static PyObject * +hamt_py_get(PyHamtObject *self, PyObject *args) +{ + PyObject *key; + PyObject *def = NULL; + + if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &def)) { + return NULL; + } + + PyObject *val = NULL; + hamt_find_t res = hamt_find(self, key, &val); + switch (res) { + case F_ERROR: + return NULL; + case F_FOUND: + Py_INCREF(val); + return val; + case F_NOT_FOUND: + if (def == NULL) { + Py_RETURN_NONE; + } + Py_INCREF(def); + return def; + default: + Py_UNREACHABLE(); + } +} + +static PyObject * +hamt_py_delete(PyHamtObject *self, PyObject *key) +{ + return (PyObject *)_PyHamt_Without(self, key); +} + +static PyObject * +hamt_py_items(PyHamtObject *self, PyObject *args) +{ + return _PyHamt_NewIterItems(self); +} + +static PyObject * +hamt_py_values(PyHamtObject *self, PyObject *args) +{ + return _PyHamt_NewIterValues(self); +} + +static PyObject * +hamt_py_keys(PyHamtObject *self, PyObject *args) +{ + return _PyHamt_NewIterKeys(self); +} + +#ifdef Py_DEBUG +static PyObject * +hamt_py_dump(PyHamtObject *self, PyObject *args) +{ + return hamt_dump(self); +} +#endif + + +static PyMethodDef PyHamt_methods[] = { + {"set", (PyCFunction)hamt_py_set, METH_VARARGS, NULL}, + {"get", (PyCFunction)hamt_py_get, METH_VARARGS, NULL}, + {"delete", (PyCFunction)hamt_py_delete, METH_O, NULL}, + {"items", (PyCFunction)hamt_py_items, METH_NOARGS, NULL}, + {"keys", (PyCFunction)hamt_py_keys, METH_NOARGS, NULL}, + {"values", (PyCFunction)hamt_py_values, METH_NOARGS, NULL}, +#ifdef Py_DEBUG + {"__dump__", (PyCFunction)hamt_py_dump, METH_NOARGS, NULL}, +#endif + {NULL, NULL} +}; + +static PySequenceMethods PyHamt_as_sequence = { + 0, /* sq_length */ + 0, /* sq_concat */ + 0, /* sq_repeat */ + 0, /* sq_item */ + 0, /* sq_slice */ + 0, /* sq_ass_item */ + 0, /* sq_ass_slice */ + (objobjproc)hamt_tp_contains, /* sq_contains */ + 0, /* sq_inplace_concat */ + 0, /* sq_inplace_repeat */ +}; + +static PyMappingMethods PyHamt_as_mapping = { + (lenfunc)hamt_tp_len, /* mp_length */ + (binaryfunc)hamt_tp_subscript, /* mp_subscript */ +}; + +PyTypeObject _PyHamt_Type = { + PyVarObject_HEAD_INIT(&PyType_Type, 0) + "hamt", + sizeof(PyHamtObject), + .tp_methods = PyHamt_methods, + .tp_as_mapping = &PyHamt_as_mapping, + .tp_as_sequence = &PyHamt_as_sequence, + .tp_iter = (getiterfunc)hamt_tp_iter, + .tp_dealloc = (destructor)hamt_tp_dealloc, + .tp_getattro = PyObject_GenericGetAttr, + .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, + .tp_richcompare = hamt_tp_richcompare, + .tp_traverse = (traverseproc)hamt_tp_traverse, + .tp_clear = (inquiry)hamt_tp_clear, + .tp_new = hamt_tp_new, + .tp_weaklistoffset = offsetof(PyHamtObject, h_weakreflist), + .tp_hash = PyObject_HashNotImplemented, +}; + + +/////////////////////////////////// Tree Node Types + + +PyTypeObject _PyHamt_ArrayNode_Type = { + PyVarObject_HEAD_INIT(&PyType_Type, 0) + "hamt_array_node", + sizeof(PyHamtNode_Array), + 0, + .tp_dealloc = (destructor)hamt_node_array_dealloc, + .tp_getattro = PyObject_GenericGetAttr, + .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, + .tp_traverse = (traverseproc)hamt_node_array_traverse, + .tp_free = PyObject_GC_Del, + .tp_hash = PyObject_HashNotImplemented, +}; + +PyTypeObject _PyHamt_BitmapNode_Type = { + PyVarObject_HEAD_INIT(&PyType_Type, 0) + "hamt_bitmap_node", + sizeof(PyHamtNode_Bitmap) - sizeof(PyObject *), + sizeof(PyObject *), + .tp_dealloc = (destructor)hamt_node_bitmap_dealloc, + .tp_getattro = PyObject_GenericGetAttr, + .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, + .tp_traverse = (traverseproc)hamt_node_bitmap_traverse, + .tp_free = PyObject_GC_Del, + .tp_hash = PyObject_HashNotImplemented, +}; + +PyTypeObject _PyHamt_CollisionNode_Type = { + PyVarObject_HEAD_INIT(&PyType_Type, 0) + "hamt_collision_node", + sizeof(PyHamtNode_Collision) - sizeof(PyObject *), + sizeof(PyObject *), + .tp_dealloc = (destructor)hamt_node_collision_dealloc, + .tp_getattro = PyObject_GenericGetAttr, + .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC, + .tp_traverse = (traverseproc)hamt_node_collision_traverse, + .tp_free = PyObject_GC_Del, + .tp_hash = PyObject_HashNotImplemented, +}; + + +int +_PyHamt_Init(void) +{ + if ((PyType_Ready(&_PyHamt_Type) < 0) || + (PyType_Ready(&_PyHamt_ArrayNode_Type) < 0) || + (PyType_Ready(&_PyHamt_BitmapNode_Type) < 0) || + (PyType_Ready(&_PyHamt_CollisionNode_Type) < 0) || + (PyType_Ready(&_PyHamtKeys_Type) < 0) || + (PyType_Ready(&_PyHamtValues_Type) < 0) || + (PyType_Ready(&_PyHamtItems_Type) < 0)) + { + return 0; + } + + return 1; +} + +void +_PyHamt_Fini(void) +{ + Py_CLEAR(_empty_hamt); + Py_CLEAR(_empty_bitmap_node); +} |