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util/addon: use AVL trees
This commit is contained in:
Kirill Primak
parent
f83b3809cf
commit
27cbc20355
2 changed files with 255 additions and 19 deletions
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@ -9,26 +9,29 @@
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#ifndef WLR_UTIL_ADDON_H
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#define WLR_UTIL_ADDON_H
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#include <wayland-server-core.h>
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#include <stdint.h>
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struct wlr_addon_set {
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// private state
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struct wl_list addons;
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struct wlr_addon *root;
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};
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struct wlr_addon;
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struct wlr_addon_interface {
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const char *name;
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// Has to call wlr_addon_finish()
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void (*destroy)(struct wlr_addon *addon);
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};
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struct wlr_addon {
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const struct wlr_addon_interface *impl;
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// private state
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struct wlr_addon_set *set;
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const void *owner;
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struct wl_list link;
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const struct wlr_addon_interface *impl;
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struct wlr_addon *parent; // NULL if it's set->root
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struct wlr_addon *left;
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struct wlr_addon *right;
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int8_t balance;
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};
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void wlr_addon_set_init(struct wlr_addon_set *set);
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261
util/addon.c
261
util/addon.c
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@ -1,18 +1,119 @@
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#include <assert.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wayland-server-core.h>
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#include <wlr/util/addon.h>
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static ptrdiff_t compare(struct wlr_addon *addon, const void *owner,
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const struct wlr_addon_interface *impl) {
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ptrdiff_t owner_diff = (ptrdiff_t)addon->owner - (ptrdiff_t)owner;
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if (owner_diff != 0) {
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return owner_diff;
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}
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return (ptrdiff_t)addon->impl - (ptrdiff_t)impl;
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}
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// A (addon (child)) => A (child)
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static void replace(struct wlr_addon *addon, struct wlr_addon *child) {
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if (addon->parent == NULL) {
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addon->set->root = child;
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} else if (addon->parent->left == addon) {
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addon->parent->left = child;
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} else { // addon->parent->right == addon
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addon->parent->right = child;
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}
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if (child != NULL) {
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child->parent = addon->parent;
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}
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}
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// parent (A, addon (B, C)) => addon (parent (A, B), C)
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static struct wlr_addon *rotate_left(struct wlr_addon *parent,
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struct wlr_addon *addon) {
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parent->right = addon->left;
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if (addon->left != NULL) {
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addon->left->parent = parent;
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}
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addon->left = parent;
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parent->parent = addon;
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if (addon->balance == 0) {
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addon->balance = -1;
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parent->balance = 1;
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} else {
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addon->balance = 0;
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parent->balance = 0;
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}
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return addon;
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}
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// parent (addon (A, B), C) => addon (A, parent (B, C))
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static struct wlr_addon *rotate_right(struct wlr_addon *parent,
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struct wlr_addon *addon) {
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parent->left = addon->right;
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if (addon->right != NULL) {
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addon->right->parent = parent;
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}
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addon->right = parent;
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parent->parent = addon;
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if (addon->balance == 0) {
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addon->balance = -1;
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parent->balance = 1;
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} else {
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addon->balance = 0;
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parent->balance = 0;
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}
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return addon;
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}
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// parent (addon (A, mid (B, C)), D) => mid (addon (A, B), parent (C, D))
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static struct wlr_addon *rotate_leftright(struct wlr_addon *parent,
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struct wlr_addon *addon) {
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struct wlr_addon *mid = addon->right;
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addon->right = mid->left;
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if (mid->left != NULL) {
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mid->left->parent = addon;
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}
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mid->left = addon;
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addon->parent = mid;
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parent->left = mid->right;
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if (mid->right != NULL) {
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mid->right->parent = parent;
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}
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mid->right = parent;
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parent->parent = mid;
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parent->balance = mid->balance > 0 ? -1 : 0;
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addon->balance = mid->balance < 0 ? 1 : 0;
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return mid;
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}
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// parent (A, addon (mid (B, C), D)) => mid (parent (A, B), addon (C, D))
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static struct wlr_addon *rotate_rightleft(struct wlr_addon *parent,
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struct wlr_addon *addon) {
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struct wlr_addon *mid = addon->left;
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addon->left = mid->right;
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if (mid->right != NULL) {
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mid->right->parent = addon;
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}
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mid->right = addon;
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addon->parent = mid;
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parent->right = mid->left;
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if (mid->left != NULL) {
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mid->left->parent = parent;
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}
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mid->left = parent;
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parent->parent = mid;
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parent->balance = mid->balance > 0 ? -1 : 0;
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addon->balance = mid->balance < 0 ? 1 : 0;
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return mid;
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}
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void wlr_addon_set_init(struct wlr_addon_set *set) {
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memset(set, 0, sizeof(*set));
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wl_list_init(&set->addons);
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}
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void wlr_addon_set_finish(struct wlr_addon_set *set) {
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struct wlr_addon *addon, *tmp;
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wl_list_for_each_safe(addon, tmp, &set->addons, link) {
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addon->impl->destroy(addon);
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while (set->root != NULL) {
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set->root->impl->destroy(set->root);
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}
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}
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@ -20,26 +121,158 @@ void wlr_addon_init(struct wlr_addon *addon, struct wlr_addon_set *set,
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const void *owner, const struct wlr_addon_interface *impl) {
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assert(owner && impl);
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memset(addon, 0, sizeof(*addon));
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struct wlr_addon *iter;
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wl_list_for_each(iter, &set->addons, link) {
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if (iter->owner == addon->owner && iter->impl == addon->impl) {
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assert(0 && "Can't have two addons of the same type with the same owner");
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struct wlr_addon *parent = NULL;
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struct wlr_addon **ptr = &set->root;
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while (*ptr != NULL) {
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parent = *ptr;
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ptrdiff_t diff = compare(*ptr, owner, impl);
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if (diff < 0) {
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ptr = &(*ptr)->left;
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} else if (diff > 0) {
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ptr = &(*ptr)->right;
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} else {
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assert(0 && "Can't have two addons with the same owner and impl");
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return;
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}
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}
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wl_list_insert(&set->addons, &addon->link);
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addon->set = set;
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addon->owner = owner;
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addon->impl = impl;
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addon->parent = parent;
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*ptr = addon;
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// Rebalance
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for (; parent != NULL; parent = parent->parent) {
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struct wlr_addon *grandparent = parent->parent;
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if (parent->left == addon) {
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if (parent->balance > 0) {
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parent->balance = 0;
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break;
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} else if (parent->balance == 0) {
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parent->balance = -1;
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addon = parent;
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continue;
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}
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if (addon->balance > 0) {
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addon = rotate_leftright(parent, addon);
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} else {
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addon = rotate_right(parent, addon);
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}
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} else { // parent->right == addon
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if (parent->balance < 0) {
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parent->balance = 0;
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break;
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} else if (parent->balance == 0) {
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parent->balance = 1;
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addon = parent;
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continue;
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}
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if (addon->balance < 0) {
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addon = rotate_rightleft(parent, addon);
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} else {
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addon = rotate_left(parent, addon);
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}
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}
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// Here, addon is the root of the rotated subtree
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addon->parent = grandparent;
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if (grandparent != NULL) {
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if (grandparent->left == parent) {
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grandparent->left = addon;
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} else { // grandparent->right == parent
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grandparent->right = addon;
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}
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} else {
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set->root = addon;
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}
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break;
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}
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}
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void wlr_addon_finish(struct wlr_addon *addon) {
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wl_list_remove(&addon->link);
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if (addon->left == NULL) {
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replace(addon, addon->right);
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} else if (addon->right == NULL) {
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replace(addon, addon->left);
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} else {
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struct wlr_addon *successor = addon->right;
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while (successor->left != NULL) {
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successor = successor->left;
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}
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if (successor->parent != addon) {
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replace(successor, successor->right);
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successor->right = addon->right;
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successor->right->parent = successor;
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}
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replace(addon, successor);
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successor->left = addon->left;
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successor->left->parent = successor;
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}
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// Rebalance
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for (struct wlr_addon *parent = addon->parent;
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parent != NULL; parent = parent->parent) {
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int balance = 0;
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struct wlr_addon *grandparent = parent->parent;
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if (parent->left == addon) {
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if (parent->balance < 0) {
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parent->balance = 0;
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addon = parent;
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continue;
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} else if (parent->balance == 0) {
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parent->balance = 1;
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break;
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}
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balance = parent->right->balance;
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if (balance < 0) {
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addon = rotate_rightleft(parent, addon);
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} else {
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addon = rotate_left(parent, addon);
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}
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} else { // parent->right == addon
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if (parent->balance < 0) {
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parent->balance = 0;
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addon = parent;
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continue;
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} else if (parent->balance == 0) {
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parent->balance = -1;
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break;
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}
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balance = parent->left->balance;
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if (balance > 0) {
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addon = rotate_leftright(parent, addon);
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} else {
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addon = rotate_right(parent, addon);
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}
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}
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// Here, addon is the root of the rotated subtree
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addon->parent = grandparent;
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if (grandparent != NULL) {
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if (grandparent->left == parent) {
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grandparent->left = addon;
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} else { // grandparent->right == parent
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grandparent->right = addon;
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}
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} else {
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addon->set->root = addon;
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}
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if (balance == 0) {
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break;
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}
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}
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}
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struct wlr_addon *wlr_addon_find(struct wlr_addon_set *set, const void *owner,
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const struct wlr_addon_interface *impl) {
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struct wlr_addon *addon;
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wl_list_for_each(addon, &set->addons, link) {
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if (addon->owner == owner && addon->impl == impl) {
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struct wlr_addon *addon = set->root;
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while (addon != NULL) {
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ptrdiff_t diff = compare(addon, owner, impl);
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if (diff < 0) {
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addon = addon->left;
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} else if (diff > 0) {
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addon = addon->right;
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} else {
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return addon;
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}
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}
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