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Diffstat (limited to 'util/qtree.c')
| -rw-r--r-- | util/qtree.c | 1390 |
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diff --git a/util/qtree.c b/util/qtree.c new file mode 100644 index 0000000000..deb46c187f --- /dev/null +++ b/util/qtree.c @@ -0,0 +1,1390 @@ +/* + * GLIB - Library of useful routines for C programming + * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald + * + * SPDX-License-Identifier: LGPL-2.1-or-later + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ + +/* + * Modified by the GLib Team and others 1997-2000. See the AUTHORS + * file for a list of people on the GLib Team. See the ChangeLog + * files for a list of changes. These files are distributed with + * GLib at ftp://ftp.gtk.org/pub/gtk/. + */ + +/* + * MT safe + */ + +#include "qemu/osdep.h" +#include "qemu/qtree.h" + +/** + * SECTION:trees-binary + * @title: Balanced Binary Trees + * @short_description: a sorted collection of key/value pairs optimized + * for searching and traversing in order + * + * The #QTree structure and its associated functions provide a sorted + * collection of key/value pairs optimized for searching and traversing + * in order. This means that most of the operations (access, search, + * insertion, deletion, ...) on #QTree are O(log(n)) in average and O(n) + * in worst case for time complexity. But, note that maintaining a + * balanced sorted #QTree of n elements is done in time O(n log(n)). + * + * To create a new #QTree use q_tree_new(). + * + * To insert a key/value pair into a #QTree use q_tree_insert() + * (O(n log(n))). + * + * To remove a key/value pair use q_tree_remove() (O(n log(n))). + * + * To look up the value corresponding to a given key, use + * q_tree_lookup() and q_tree_lookup_extended(). + * + * To find out the number of nodes in a #QTree, use q_tree_nnodes(). To + * get the height of a #QTree, use q_tree_height(). + * + * To traverse a #QTree, calling a function for each node visited in + * the traversal, use q_tree_foreach(). + * + * To destroy a #QTree, use q_tree_destroy(). + **/ + +#define MAX_GTREE_HEIGHT 40 + +/** + * QTree: + * + * The QTree struct is an opaque data structure representing a + * [balanced binary tree][glib-Balanced-Binary-Trees]. It should be + * accessed only by using the following functions. + */ +struct _QTree { + QTreeNode *root; + GCompareDataFunc key_compare; + GDestroyNotify key_destroy_func; + GDestroyNotify value_destroy_func; + gpointer key_compare_data; + guint nnodes; + gint ref_count; +}; + +struct _QTreeNode { + gpointer key; /* key for this node */ + gpointer value; /* value stored at this node */ + QTreeNode *left; /* left subtree */ + QTreeNode *right; /* right subtree */ + gint8 balance; /* height (right) - height (left) */ + guint8 left_child; + guint8 right_child; +}; + + +static QTreeNode *q_tree_node_new(gpointer key, + gpointer value); +static QTreeNode *q_tree_insert_internal(QTree *tree, + gpointer key, + gpointer value, + gboolean replace); +static gboolean q_tree_remove_internal(QTree *tree, + gconstpointer key, + gboolean steal); +static QTreeNode *q_tree_node_balance(QTreeNode *node); +static QTreeNode *q_tree_find_node(QTree *tree, + gconstpointer key); +static QTreeNode *q_tree_node_search(QTreeNode *node, + GCompareFunc search_func, + gconstpointer data); +static QTreeNode *q_tree_node_rotate_left(QTreeNode *node); +static QTreeNode *q_tree_node_rotate_right(QTreeNode *node); +#ifdef Q_TREE_DEBUG +static void q_tree_node_check(QTreeNode *node); +#endif + +static QTreeNode* +q_tree_node_new(gpointer key, + gpointer value) +{ + QTreeNode *node = g_new(QTreeNode, 1); + + node->balance = 0; + node->left = NULL; + node->right = NULL; + node->left_child = FALSE; + node->right_child = FALSE; + node->key = key; + node->value = value; + + return node; +} + +/** + * q_tree_new: + * @key_compare_func: the function used to order the nodes in the #QTree. + * It should return values similar to the standard strcmp() function - + * 0 if the two arguments are equal, a negative value if the first argument + * comes before the second, or a positive value if the first argument comes + * after the second. + * + * Creates a new #QTree. + * + * Returns: a newly allocated #QTree + */ +QTree * +q_tree_new(GCompareFunc key_compare_func) +{ + g_return_val_if_fail(key_compare_func != NULL, NULL); + + return q_tree_new_full((GCompareDataFunc) key_compare_func, NULL, + NULL, NULL); +} + +/** + * q_tree_new_with_data: + * @key_compare_func: qsort()-style comparison function + * @key_compare_data: data to pass to comparison function + * + * Creates a new #QTree with a comparison function that accepts user data. + * See q_tree_new() for more details. + * + * Returns: a newly allocated #QTree + */ +QTree * +q_tree_new_with_data(GCompareDataFunc key_compare_func, + gpointer key_compare_data) +{ + g_return_val_if_fail(key_compare_func != NULL, NULL); + + return q_tree_new_full(key_compare_func, key_compare_data, + NULL, NULL); +} + +/** + * q_tree_new_full: + * @key_compare_func: qsort()-style comparison function + * @key_compare_data: data to pass to comparison function + * @key_destroy_func: a function to free the memory allocated for the key + * used when removing the entry from the #QTree or %NULL if you don't + * want to supply such a function + * @value_destroy_func: a function to free the memory allocated for the + * value used when removing the entry from the #QTree or %NULL if you + * don't want to supply such a function + * + * Creates a new #QTree like q_tree_new() and allows to specify functions + * to free the memory allocated for the key and value that get called when + * removing the entry from the #QTree. + * + * Returns: a newly allocated #QTree + */ +QTree * +q_tree_new_full(GCompareDataFunc key_compare_func, + gpointer key_compare_data, + GDestroyNotify key_destroy_func, + GDestroyNotify value_destroy_func) +{ + QTree *tree; + + g_return_val_if_fail(key_compare_func != NULL, NULL); + + tree = g_new(QTree, 1); + tree->root = NULL; + tree->key_compare = key_compare_func; + tree->key_destroy_func = key_destroy_func; + tree->value_destroy_func = value_destroy_func; + tree->key_compare_data = key_compare_data; + tree->nnodes = 0; + tree->ref_count = 1; + + return tree; +} + +/** + * q_tree_node_first: + * @tree: a #QTree + * + * Returns the first in-order node of the tree, or %NULL + * for an empty tree. + * + * Returns: (nullable) (transfer none): the first node in the tree + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_node_first(QTree *tree) +{ + QTreeNode *tmp; + + g_return_val_if_fail(tree != NULL, NULL); + + if (!tree->root) { + return NULL; + } + + tmp = tree->root; + + while (tmp->left_child) { + tmp = tmp->left; + } + + return tmp; +} + +/** + * q_tree_node_previous + * @node: a #QTree node + * + * Returns the previous in-order node of the tree, or %NULL + * if the passed node was already the first one. + * + * Returns: (nullable) (transfer none): the previous node in the tree + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_node_previous(QTreeNode *node) +{ + QTreeNode *tmp; + + g_return_val_if_fail(node != NULL, NULL); + + tmp = node->left; + + if (node->left_child) { + while (tmp->right_child) { + tmp = tmp->right; + } + } + + return tmp; +} + +/** + * q_tree_node_next + * @node: a #QTree node + * + * Returns the next in-order node of the tree, or %NULL + * if the passed node was already the last one. + * + * Returns: (nullable) (transfer none): the next node in the tree + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_node_next(QTreeNode *node) +{ + QTreeNode *tmp; + + g_return_val_if_fail(node != NULL, NULL); + + tmp = node->right; + + if (node->right_child) { + while (tmp->left_child) { + tmp = tmp->left; + } + } + + return tmp; +} + +/** + * q_tree_remove_all: + * @tree: a #QTree + * + * Removes all nodes from a #QTree and destroys their keys and values, + * then resets the #QTree’s root to %NULL. + * + * Since: 2.70 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static void +q_tree_remove_all(QTree *tree) +{ + QTreeNode *node; + QTreeNode *next; + + g_return_if_fail(tree != NULL); + + node = q_tree_node_first(tree); + + while (node) { + next = q_tree_node_next(node); + + if (tree->key_destroy_func) { + tree->key_destroy_func(node->key); + } + if (tree->value_destroy_func) { + tree->value_destroy_func(node->value); + } + g_free(node); + +#ifdef Q_TREE_DEBUG + g_assert(tree->nnodes > 0); + tree->nnodes--; +#endif + + node = next; + } + +#ifdef Q_TREE_DEBUG + g_assert(tree->nnodes == 0); +#endif + + tree->root = NULL; +#ifndef Q_TREE_DEBUG + tree->nnodes = 0; +#endif +} + +/** + * q_tree_ref: + * @tree: a #QTree + * + * Increments the reference count of @tree by one. + * + * It is safe to call this function from any thread. + * + * Returns: the passed in #QTree + * + * Since: 2.22 + */ +QTree * +q_tree_ref(QTree *tree) +{ + g_return_val_if_fail(tree != NULL, NULL); + + g_atomic_int_inc(&tree->ref_count); + + return tree; +} + +/** + * q_tree_unref: + * @tree: a #QTree + * + * Decrements the reference count of @tree by one. + * If the reference count drops to 0, all keys and values will + * be destroyed (if destroy functions were specified) and all + * memory allocated by @tree will be released. + * + * It is safe to call this function from any thread. + * + * Since: 2.22 + */ +void +q_tree_unref(QTree *tree) +{ + g_return_if_fail(tree != NULL); + + if (g_atomic_int_dec_and_test(&tree->ref_count)) { + q_tree_remove_all(tree); + g_free(tree); + } +} + +/** + * q_tree_destroy: + * @tree: a #QTree + * + * Removes all keys and values from the #QTree and decreases its + * reference count by one. If keys and/or values are dynamically + * allocated, you should either free them first or create the #QTree + * using q_tree_new_full(). In the latter case the destroy functions + * you supplied will be called on all keys and values before destroying + * the #QTree. + */ +void +q_tree_destroy(QTree *tree) +{ + g_return_if_fail(tree != NULL); + + q_tree_remove_all(tree); + q_tree_unref(tree); +} + +/** + * q_tree_insert_node: + * @tree: a #QTree + * @key: the key to insert + * @value: the value corresponding to the key + * + * Inserts a key/value pair into a #QTree. + * + * If the given key already exists in the #QTree its corresponding value + * is set to the new value. If you supplied a @value_destroy_func when + * creating the #QTree, the old value is freed using that function. If + * you supplied a @key_destroy_func when creating the #QTree, the passed + * key is freed using that function. + * + * The tree is automatically 'balanced' as new key/value pairs are added, + * so that the distance from the root to every leaf is as small as possible. + * The cost of maintaining a balanced tree while inserting new key/value + * result in a O(n log(n)) operation where most of the other operations + * are O(log(n)). + * + * Returns: (transfer none): the inserted (or set) node. + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_insert_node(QTree *tree, + gpointer key, + gpointer value) +{ + QTreeNode *node; + + g_return_val_if_fail(tree != NULL, NULL); + + node = q_tree_insert_internal(tree, key, value, FALSE); + +#ifdef Q_TREE_DEBUG + q_tree_node_check(tree->root); +#endif + + return node; +} + +/** + * q_tree_insert: + * @tree: a #QTree + * @key: the key to insert + * @value: the value corresponding to the key + * + * Inserts a key/value pair into a #QTree. + * + * Inserts a new key and value into a #QTree as q_tree_insert_node() does, + * only this function does not return the inserted or set node. + */ +void +q_tree_insert(QTree *tree, + gpointer key, + gpointer value) +{ + q_tree_insert_node(tree, key, value); +} + +/** + * q_tree_replace_node: + * @tree: a #QTree + * @key: the key to insert + * @value: the value corresponding to the key + * + * Inserts a new key and value into a #QTree similar to q_tree_insert_node(). + * The difference is that if the key already exists in the #QTree, it gets + * replaced by the new key. If you supplied a @value_destroy_func when + * creating the #QTree, the old value is freed using that function. If you + * supplied a @key_destroy_func when creating the #QTree, the old key is + * freed using that function. + * + * The tree is automatically 'balanced' as new key/value pairs are added, + * so that the distance from the root to every leaf is as small as possible. + * + * Returns: (transfer none): the inserted (or set) node. + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_replace_node(QTree *tree, + gpointer key, + gpointer value) +{ + QTreeNode *node; + + g_return_val_if_fail(tree != NULL, NULL); + + node = q_tree_insert_internal(tree, key, value, TRUE); + +#ifdef Q_TREE_DEBUG + q_tree_node_check(tree->root); +#endif + + return node; +} + +/** + * q_tree_replace: + * @tree: a #QTree + * @key: the key to insert + * @value: the value corresponding to the key + * + * Inserts a new key and value into a #QTree as q_tree_replace_node() does, + * only this function does not return the inserted or set node. + */ +void +q_tree_replace(QTree *tree, + gpointer key, + gpointer value) +{ + q_tree_replace_node(tree, key, value); +} + +/* internal insert routine */ +static QTreeNode * +q_tree_insert_internal(QTree *tree, + gpointer key, + gpointer value, + gboolean replace) +{ + QTreeNode *node, *retnode; + QTreeNode *path[MAX_GTREE_HEIGHT]; + int idx; + + g_return_val_if_fail(tree != NULL, NULL); + + if (!tree->root) { + tree->root = q_tree_node_new(key, value); + tree->nnodes++; + return tree->root; + } + + idx = 0; + path[idx++] = NULL; + node = tree->root; + + while (1) { + int cmp = tree->key_compare(key, node->key, tree->key_compare_data); + + if (cmp == 0) { + if (tree->value_destroy_func) { + tree->value_destroy_func(node->value); + } + + node->value = value; + + if (replace) { + if (tree->key_destroy_func) { + tree->key_destroy_func(node->key); + } + + node->key = key; + } else { + /* free the passed key */ + if (tree->key_destroy_func) { + tree->key_destroy_func(key); + } + } + + return node; + } else if (cmp < 0) { + if (node->left_child) { + path[idx++] = node; + node = node->left; + } else { + QTreeNode *child = q_tree_node_new(key, value); + + child->left = node->left; + child->right = node; + node->left = child; + node->left_child = TRUE; + node->balance -= 1; + + tree->nnodes++; + + retnode = child; + break; + } + } else { + if (node->right_child) { + path[idx++] = node; + node = node->right; + } else { + QTreeNode *child = q_tree_node_new(key, value); + + child->right = node->right; + child->left = node; + node->right = child; + node->right_child = TRUE; + node->balance += 1; + + tree->nnodes++; + + retnode = child; + break; + } + } + } + + /* + * Restore balance. This is the goodness of a non-recursive + * implementation, when we are done with balancing we 'break' + * the loop and we are done. + */ + while (1) { + QTreeNode *bparent = path[--idx]; + gboolean left_node = (bparent && node == bparent->left); + g_assert(!bparent || bparent->left == node || bparent->right == node); + + if (node->balance < -1 || node->balance > 1) { + node = q_tree_node_balance(node); + if (bparent == NULL) { + tree->root = node; + } else if (left_node) { + bparent->left = node; + } else { + bparent->right = node; + } + } + + if (node->balance == 0 || bparent == NULL) { + break; + } + + if (left_node) { + bparent->balance -= 1; + } else { + bparent->balance += 1; + } + + node = bparent; + } + + return retnode; +} + +/** + * q_tree_remove: + * @tree: a #QTree + * @key: the key to remove + * + * Removes a key/value pair from a #QTree. + * + * If the #QTree was created using q_tree_new_full(), the key and value + * are freed using the supplied destroy functions, otherwise you have to + * make sure that any dynamically allocated values are freed yourself. + * If the key does not exist in the #QTree, the function does nothing. + * + * The cost of maintaining a balanced tree while removing a key/value + * result in a O(n log(n)) operation where most of the other operations + * are O(log(n)). + * + * Returns: %TRUE if the key was found (prior to 2.8, this function + * returned nothing) + */ +gboolean +q_tree_remove(QTree *tree, + gconstpointer key) +{ + gboolean removed; + + g_return_val_if_fail(tree != NULL, FALSE); + + removed = q_tree_remove_internal(tree, key, FALSE); + +#ifdef Q_TREE_DEBUG + q_tree_node_check(tree->root); +#endif + + return removed; +} + +/** + * q_tree_steal: + * @tree: a #QTree + * @key: the key to remove + * + * Removes a key and its associated value from a #QTree without calling + * the key and value destroy functions. + * + * If the key does not exist in the #QTree, the function does nothing. + * + * Returns: %TRUE if the key was found (prior to 2.8, this function + * returned nothing) + */ +gboolean +q_tree_steal(QTree *tree, + gconstpointer key) +{ + gboolean removed; + + g_return_val_if_fail(tree != NULL, FALSE); + + removed = q_tree_remove_internal(tree, key, TRUE); + +#ifdef Q_TREE_DEBUG + q_tree_node_check(tree->root); +#endif + + return removed; +} + +/* internal remove routine */ +static gboolean +q_tree_remove_internal(QTree *tree, + gconstpointer key, + gboolean steal) +{ + QTreeNode *node, *parent, *balance; + QTreeNode *path[MAX_GTREE_HEIGHT]; + int idx; + gboolean left_node; + + g_return_val_if_fail(tree != NULL, FALSE); + + if (!tree->root) { + return FALSE; + } + + idx = 0; + path[idx++] = NULL; + node = tree->root; + + while (1) { + int cmp = tree->key_compare(key, node->key, tree->key_compare_data); + + if (cmp == 0) { + break; + } else if (cmp < 0) { + if (!node->left_child) { + return FALSE; + } + + path[idx++] = node; + node = node->left; + } else { + if (!node->right_child) { + return FALSE; + } + + path[idx++] = node; + node = node->right; + } + } + + /* + * The following code is almost equal to q_tree_remove_node, + * except that we do not have to call q_tree_node_parent. + */ + balance = parent = path[--idx]; + g_assert(!parent || parent->left == node || parent->right == node); + left_node = (parent && node == parent->left); + + if (!node->left_child) { + if (!node->right_child) { + if (!parent) { + tree->root = NULL; + } else if (left_node) { + parent->left_child = FALSE; + parent->left = node->left; + parent->balance += 1; + } else { + parent->right_child = FALSE; + parent->right = node->right; + parent->balance -= 1; + } + } else { + /* node has a right child */ + QTreeNode *tmp = q_tree_node_next(node); + tmp->left = node->left; + + if (!parent) { + tree->root = node->right; + } else if (left_node) { + parent->left = node->right; + parent->balance += 1; + } else { + parent->right = node->right; + parent->balance -= 1; + } + } + } else { + /* node has a left child */ + if (!node->right_child) { + QTreeNode *tmp = q_tree_node_previous(node); + tmp->right = node->right; + + if (parent == NULL) { + tree->root = node->left; + } else if (left_node) { + parent->left = node->left; + parent->balance += 1; + } else { + parent->right = node->left; + parent->balance -= 1; + } + } else { + /* node has a both children (pant, pant!) */ + QTreeNode *prev = node->left; + QTreeNode *next = node->right; + QTreeNode *nextp = node; + int old_idx = idx + 1; + idx++; + + /* path[idx] == parent */ + /* find the immediately next node (and its parent) */ + while (next->left_child) { + path[++idx] = nextp = next; + next = next->left; + } + + path[old_idx] = next; + balance = path[idx]; + + /* remove 'next' from the tree */ + if (nextp != node) { + if (next->right_child) { + nextp->left = next->right; + } else { + nextp->left_child = FALSE; + } + nextp->balance += 1; + + next->right_child = TRUE; + next->right = node->right; + } else { + node->balance -= 1; + } + + /* set the prev to point to the right place */ + while (prev->right_child) { + prev = prev->right; + } + prev->right = next; + + /* prepare 'next' to replace 'node' */ + next->left_child = TRUE; + next->left = node->left; + next->balance = node->balance; + + if (!parent) { + tree->root = next; + } else if (left_node) { + parent->left = next; + } else { + parent->right = next; + } + } + } + + /* restore balance */ + if (balance) { + while (1) { + QTreeNode *bparent = path[--idx]; + g_assert(!bparent || + bparent->left == balance || + bparent->right == balance); + left_node = (bparent && balance == bparent->left); + + if (balance->balance < -1 || balance->balance > 1) { + balance = q_tree_node_balance(balance); + if (!bparent) { + tree->root = balance; + } else if (left_node) { + bparent->left = balance; + } else { + bparent->right = balance; + } + } + + if (balance->balance != 0 || !bparent) { + break; + } + + if (left_node) { + bparent->balance += 1; + } else { + bparent->balance -= 1; + } + + balance = bparent; + } + } + + if (!steal) { + if (tree->key_destroy_func) { + tree->key_destroy_func(node->key); + } + if (tree->value_destroy_func) { + tree->value_destroy_func(node->value); + } + } + + g_free(node); + + tree->nnodes--; + + return TRUE; +} + +/** + * q_tree_lookup_node: + * @tree: a #QTree + * @key: the key to look up + * + * Gets the tree node corresponding to the given key. Since a #QTree is + * automatically balanced as key/value pairs are added, key lookup + * is O(log n) (where n is the number of key/value pairs in the tree). + * + * Returns: (nullable) (transfer none): the tree node corresponding to + * the key, or %NULL if the key was not found + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_lookup_node(QTree *tree, + gconstpointer key) +{ + g_return_val_if_fail(tree != NULL, NULL); + + return q_tree_find_node(tree, key); +} + +/** + * q_tree_lookup: + * @tree: a #QTree + * @key: the key to look up + * + * Gets the value corresponding to the given key. Since a #QTree is + * automatically balanced as key/value pairs are added, key lookup + * is O(log n) (where n is the number of key/value pairs in the tree). + * + * Returns: the value corresponding to the key, or %NULL + * if the key was not found + */ +gpointer +q_tree_lookup(QTree *tree, + gconstpointer key) +{ + QTreeNode *node; + + node = q_tree_lookup_node(tree, key); + + return node ? node->value : NULL; +} + +/** + * q_tree_lookup_extended: + * @tree: a #QTree + * @lookup_key: the key to look up + * @orig_key: (out) (optional) (nullable): returns the original key + * @value: (out) (optional) (nullable): returns the value associated with + * the key + * + * Looks up a key in the #QTree, returning the original key and the + * associated value. This is useful if you need to free the memory + * allocated for the original key, for example before calling + * q_tree_remove(). + * + * Returns: %TRUE if the key was found in the #QTree + */ +gboolean +q_tree_lookup_extended(QTree *tree, + gconstpointer lookup_key, + gpointer *orig_key, + gpointer *value) +{ + QTreeNode *node; + + g_return_val_if_fail(tree != NULL, FALSE); + + node = q_tree_find_node(tree, lookup_key); + + if (node) { + if (orig_key) { + *orig_key = node->key; + } + if (value) { + *value = node->value; + } + return TRUE; + } else { + return FALSE; + } +} + +/** + * q_tree_foreach: + * @tree: a #QTree + * @func: the function to call for each node visited. + * If this function returns %TRUE, the traversal is stopped. + * @user_data: user data to pass to the function + * + * Calls the given function for each of the key/value pairs in the #QTree. + * The function is passed the key and value of each pair, and the given + * @data parameter. The tree is traversed in sorted order. + * + * The tree may not be modified while iterating over it (you can't + * add/remove items). To remove all items matching a predicate, you need + * to add each item to a list in your #GTraverseFunc as you walk over + * the tree, then walk the list and remove each item. + */ +void +q_tree_foreach(QTree *tree, + GTraverseFunc func, + gpointer user_data) +{ + QTreeNode *node; + + g_return_if_fail(tree != NULL); + + if (!tree->root) { + return; + } + + node = q_tree_node_first(tree); + + while (node) { + if ((*func)(node->key, node->value, user_data)) { + break; + } + + node = q_tree_node_next(node); + } +} + +/** + * q_tree_search_node: + * @tree: a #QTree + * @search_func: a function used to search the #QTree + * @user_data: the data passed as the second argument to @search_func + * + * Searches a #QTree using @search_func. + * + * The @search_func is called with a pointer to the key of a key/value + * pair in the tree, and the passed in @user_data. If @search_func returns + * 0 for a key/value pair, then the corresponding node is returned as + * the result of q_tree_search(). If @search_func returns -1, searching + * will proceed among the key/value pairs that have a smaller key; if + * @search_func returns 1, searching will proceed among the key/value + * pairs that have a larger key. + * + * Returns: (nullable) (transfer none): the node corresponding to the + * found key, or %NULL if the key was not found + * + * Since: 2.68 in GLib. Internal in Qtree, i.e. not in the public API. + */ +static QTreeNode * +q_tree_search_node(QTree *tree, + GCompareFunc search_func, + gconstpointer user_data) +{ + g_return_val_if_fail(tree != NULL, NULL); + + if (!tree->root) { + return NULL; + } + + return q_tree_node_search(tree->root, search_func, user_data); +} + +/** + * q_tree_search: + * @tree: a #QTree + * @search_func: a function used to search the #QTree + * @user_data: the data passed as the second argument to @search_func + * + * Searches a #QTree using @search_func. + * + * The @search_func is called with a pointer to the key of a key/value + * pair in the tree, and the passed in @user_data. If @search_func returns + * 0 for a key/value pair, then the corresponding value is returned as + * the result of q_tree_search(). If @search_func returns -1, searching + * will proceed among the key/value pairs that have a smaller key; if + * @search_func returns 1, searching will proceed among the key/value + * pairs that have a larger key. + * + * Returns: the value corresponding to the found key, or %NULL + * if the key was not found + */ +gpointer +q_tree_search(QTree *tree, + GCompareFunc search_func, + gconstpointer user_data) +{ + QTreeNode *node; + + node = q_tree_search_node(tree, search_func, user_data); + + return node ? node->value : NULL; +} + +/** + * q_tree_height: + * @tree: a #QTree + * + * Gets the height of a #QTree. + * + * If the #QTree contains no nodes, the height is 0. + * If the #QTree contains only one root node the height is 1. + * If the root node has children the height is 2, etc. + * + * Returns: the height of @tree + */ +gint +q_tree_height(QTree *tree) +{ + QTreeNode *node; + gint height; + + g_return_val_if_fail(tree != NULL, 0); + + if (!tree->root) { + return 0; + } + + height = 0; + node = tree->root; + + while (1) { + height += 1 + MAX(node->balance, 0); + + if (!node->left_child) { + return height; + } + + node = node->left; + } +} + +/** + * q_tree_nnodes: + * @tree: a #QTree + * + * Gets the number of nodes in a #QTree. + * + * Returns: the number of nodes in @tree + */ +gint +q_tree_nnodes(QTree *tree) +{ + g_return_val_if_fail(tree != NULL, 0); + + return tree->nnodes; +} + +static QTreeNode * +q_tree_node_balance(QTreeNode *node) +{ + if (node->balance < -1) { + if (node->left->balance > 0) { + node->left = q_tree_node_rotate_left(node->left); + } + node = q_tree_node_rotate_right(node); + } else if (node->balance > 1) { + if (node->right->balance < 0) { + node->right = q_tree_node_rotate_right(node->right); + } + node = q_tree_node_rotate_left(node); + } + + return node; +} + +static QTreeNode * +q_tree_find_node(QTree *tree, + gconstpointer key) +{ + QTreeNode *node; + gint cmp; + + node = tree->root; + if (!node) { + return NULL; + } + + while (1) { + cmp = tree->key_compare(key, node->key, tree->key_compare_data); + if (cmp == 0) { + return node; + } else if (cmp < 0) { + if (!node->left_child) { + return NULL; + } + + node = node->left; + } else { + if (!node->right_child) { + return NULL; + } + + node = node->right; + } + } +} + +static QTreeNode * +q_tree_node_search(QTreeNode *node, + GCompareFunc search_func, + gconstpointer data) +{ + gint dir; + + if (!node) { + return NULL; + } + + while (1) { + dir = (*search_func)(node->key, data); + if (dir == 0) { + return node; + } else if (dir < 0) { + if (!node->left_child) { + return NULL; + } + + node = node->left; + } else { + if (!node->right_child) { + return NULL; + } + + node = node->right; + } + } +} + +static QTreeNode * +q_tree_node_rotate_left(QTreeNode *node) +{ + QTreeNode *right; + gint a_bal; + gint b_bal; + + right = node->right; + + if (right->left_child) { + node->right = right->left; + } else { + node->right_child = FALSE; + right->left_child = TRUE; + } + right->left = node; + + a_bal = node->balance; + b_bal = right->balance; + + if (b_bal <= 0) { + if (a_bal >= 1) { + right->balance = b_bal - 1; + } else { + right->balance = a_bal + b_bal - 2; + } + node->balance = a_bal - 1; + } else { + if (a_bal <= b_bal) { + right->balance = a_bal - 2; + } else { + right->balance = b_bal - 1; + } + node->balance = a_bal - b_bal - 1; + } + + return right; +} + +static QTreeNode * +q_tree_node_rotate_right(QTreeNode *node) +{ + QTreeNode *left; + gint a_bal; + gint b_bal; + + left = node->left; + + if (left->right_child) { + node->left = left->right; + } else { + node->left_child = FALSE; + left->right_child = TRUE; + } + left->right = node; + + a_bal = node->balance; + b_bal = left->balance; + + if (b_bal <= 0) { + if (b_bal > a_bal) { + left->balance = b_bal + 1; + } else { + left->balance = a_bal + 2; + } + node->balance = a_bal - b_bal + 1; + } else { + if (a_bal <= -1) { + left->balance = b_bal + 1; + } else { + left->balance = a_bal + b_bal + 2; + } + node->balance = a_bal + 1; + } + + return left; +} + +#ifdef Q_TREE_DEBUG +static gint +q_tree_node_height(QTreeNode *node) +{ + gint left_height; + gint right_height; + + if (node) { + left_height = 0; + right_height = 0; + + if (node->left_child) { + left_height = q_tree_node_height(node->left); + } + + if (node->right_child) { + right_height = q_tree_node_height(node->right); + } + + return MAX(left_height, right_height) + 1; + } + + return 0; +} + +static void q_tree_node_check(QTreeNode *node) +{ + gint left_height; + gint right_height; + gint balance; + QTreeNode *tmp; + + if (node) { + if (node->left_child) { + tmp = q_tree_node_previous(node); + g_assert(tmp->right == node); + } + + if (node->right_child) { + tmp = q_tree_node_next(node); + g_assert(tmp->left == node); + } + + left_height = 0; + right_height = 0; + + if (node->left_child) { + left_height = q_tree_node_height(node->left); + } + if (node->right_child) { + right_height = q_tree_node_height(node->right); + } + + balance = right_height - left_height; + g_assert(balance == node->balance); + + if (node->left_child) { + q_tree_node_check(node->left); + } + if (node->right_child) { + q_tree_node_check(node->right); + } + } +} +#endif |