/************************************************************************* * * Copyright (C) 2018-2020 Ruilin Peng (Nick) . * * smartdns is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * smartdns 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ #ifndef _GENERIC_RBTREE_H #define _GENERIC_RBTREE_H #include struct rb_node { unsigned long __rb_parent_color; struct rb_node *rb_right; struct rb_node *rb_left; } __attribute__((aligned(sizeof(long)))); /* The alignment might seem pointless, but allegedly CRIS needs it */ struct rb_root { struct rb_node *rb_node; }; #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) #define RB_ROOT \ (struct rb_root) \ { \ NULL, \ } #define rb_entry(ptr, type, member) container_of(ptr, type, member) #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL) /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */ #define RB_EMPTY_NODE(node) ((node)->__rb_parent_color == (unsigned long)(node)) #define RB_CLEAR_NODE(node) ((node)->__rb_parent_color = (unsigned long)(node)) extern void rb_insert_color(struct rb_node *, struct rb_root *); extern void rb_erase(struct rb_node *, struct rb_root *); /* Find logical next and previous nodes in a tree */ extern struct rb_node *rb_next(const struct rb_node *); extern struct rb_node *rb_prev(const struct rb_node *); extern struct rb_node *rb_first(const struct rb_root *); extern struct rb_node *rb_last(const struct rb_root *); /* Postorder iteration - always visit the parent after its children */ extern struct rb_node *rb_first_postorder(const struct rb_root *); extern struct rb_node *rb_next_postorder(const struct rb_node *); /* Fast replacement of a single node without remove/rebalance/add/rebalance */ extern void rb_replace_node(struct rb_node *victim, struct rb_node *new_node, struct rb_root *root); static inline void rb_link_node(struct rb_node *node, struct rb_node *parent, struct rb_node **rb_link) { node->__rb_parent_color = (unsigned long)parent; node->rb_left = node->rb_right = NULL; *rb_link = node; } #define rb_entry_safe(ptr, type, member) \ ({ \ typeof(ptr) ____ptr = (ptr); \ ____ptr ? rb_entry(____ptr, type, member) : NULL; \ }) /* * Handy for checking that we are not deleting an entry that is * already in a list, found in block/{blk-throttle,cfq-iosched}.c, * probably should be moved to lib/rbtree.c... */ static inline void rb_erase_init(struct rb_node *n, struct rb_root *root) { rb_erase(n, root); RB_CLEAR_NODE(n); } /* * Please note - only struct rb_augment_callbacks and the prototypes for * rb_insert_augmented() and rb_erase_augmented() are intended to be public. * The rest are implementation details you are not expected to depend on. * * See Documentation/rbtree.txt for documentation and samples. */ struct rb_augment_callbacks { void (*propagate)(struct rb_node *node, struct rb_node *stop); void (*copy)(struct rb_node *old_node, struct rb_node *new_node); void (*rotate)(struct rb_node *old_node, struct rb_node *new_node); }; extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, void (*augment_rotate)(struct rb_node *old_node, struct rb_node *new_node)); /* * Fixup the rbtree and update the augmented information when rebalancing. * * On insertion, the user must update the augmented information on the path * leading to the inserted node, then call rb_link_node() as usual and * rb_augment_inserted() instead of the usual rb_insert_color() call. * If rb_augment_inserted() rebalances the rbtree, it will callback into * a user provided function to update the augmented information on the * affected subtrees. */ static inline void rb_insert_augmented(struct rb_node *node, struct rb_root *root, const struct rb_augment_callbacks *augment) { __rb_insert_augmented(node, root, augment->rotate); } #define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \ rbtype, rbaugmented, rbcompute) \ static inline void \ rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \ { \ while (rb != stop) { \ rbstruct *node = rb_entry(rb, rbstruct, rbfield); \ rbtype augmented = rbcompute(node); \ if (node->rbaugmented == augmented) \ break; \ node->rbaugmented = augmented; \ rb = rb_parent(&node->rbfield); \ } \ } \ static inline void \ rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \ { \ rbstruct *old_node = rb_entry(rb_old, rbstruct, rbfield); \ rbstruct *new_node = rb_entry(rb_new, rbstruct, rbfield); \ new_node->rbaugmented = old_node->rbaugmented; \ } \ static void \ rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \ { \ rbstruct *old_node = rb_entry(rb_old, rbstruct, rbfield); \ rbstruct *new_node = rb_entry(rb_new, rbstruct, rbfield); \ new_node->rbaugmented = old_node->rbaugmented; \ old_node->rbaugmented = rbcompute(old_node); \ } \ rbstatic const struct rb_augment_callbacks rbname = { \ rbname ## _propagate, rbname ## _copy, rbname ## _rotate \ }; #define RB_RED 0 #define RB_BLACK 1 #define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) #define __rb_color(pc) ((pc) & 1) #define __rb_is_black(pc) __rb_color(pc) #define __rb_is_red(pc) (!__rb_color(pc)) #define rb_color(rb) __rb_color((rb)->__rb_parent_color) #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color) #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color) static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) { rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; } static inline void rb_set_parent_color(struct rb_node *rb, struct rb_node *p, int color) { rb->__rb_parent_color = (unsigned long)p | color; } static inline void __rb_change_child(struct rb_node *old_node, struct rb_node *new_node, struct rb_node *parent, struct rb_root *root) { if (parent) { if (parent->rb_left == old_node) parent->rb_left = new_node; else parent->rb_right = new_node; } else root->rb_node = new_node; } extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, void (*augment_rotate)(struct rb_node *old_node, struct rb_node *new_node)); static inline struct rb_node * __rb_erase_augmented(struct rb_node *node, struct rb_root *root, const struct rb_augment_callbacks *augment) { struct rb_node *child = node->rb_right, *tmp = node->rb_left; struct rb_node *parent, *rebalance; unsigned long pc; if (!tmp) { /* * Case 1: node to erase has no more than 1 child (easy!) * * Note that if there is one child it must be red due to 5) * and node must be black due to 4). We adjust colors locally * so as to bypass __rb_erase_color() later on. */ pc = node->__rb_parent_color; parent = __rb_parent(pc); __rb_change_child(node, child, parent, root); if (child) { child->__rb_parent_color = pc; rebalance = NULL; } else rebalance = __rb_is_black(pc) ? parent : NULL; tmp = parent; } else if (!child) { /* Still case 1, but this time the child is node->rb_left */ tmp->__rb_parent_color = pc = node->__rb_parent_color; parent = __rb_parent(pc); __rb_change_child(node, tmp, parent, root); rebalance = NULL; tmp = parent; } else { struct rb_node *successor = child, *child2; tmp = child->rb_left; if (!tmp) { /* * Case 2: node's successor is its right child * * (n) (s) * / \ / \ * (x) (s) -> (x) (c) * \ * (c) */ parent = successor; child2 = successor->rb_right; augment->copy(node, successor); } else { /* * Case 3: node's successor is leftmost under * node's right child subtree * * (n) (s) * / \ / \ * (x) (y) -> (x) (y) * / / * (p) (p) * / / * (s) (c) * \ * (c) */ do { parent = successor; successor = tmp; tmp = tmp->rb_left; } while (tmp); parent->rb_left = child2 = successor->rb_right; successor->rb_right = child; rb_set_parent(child, successor); augment->copy(node, successor); augment->propagate(parent, successor); } successor->rb_left = tmp = node->rb_left; rb_set_parent(tmp, successor); pc = node->__rb_parent_color; tmp = __rb_parent(pc); __rb_change_child(node, successor, tmp, root); if (child2) { successor->__rb_parent_color = pc; rb_set_parent_color(child2, parent, RB_BLACK); rebalance = NULL; } else { unsigned long pc2 = successor->__rb_parent_color; successor->__rb_parent_color = pc; rebalance = __rb_is_black(pc2) ? parent : NULL; } tmp = successor; } augment->propagate(tmp, NULL); return rebalance; } static inline void rb_erase_augmented(struct rb_node *node, struct rb_root *root, const struct rb_augment_callbacks *augment) { struct rb_node *rebalance = __rb_erase_augmented(node, root, augment); if (rebalance) __rb_erase_color(rebalance, root, augment->rotate); } #endif /* _GENERIC_RBTREE_H */