From 4305d024938113df5d73021a09eb2a991f54ca2f Mon Sep 17 00:00:00 2001 From: Dimitri John Ledkov Date: Mon, 13 Feb 2017 11:24:33 +0000 Subject: New upstream release Closes: #849353, #817806, #854915, #845473 --- rbtree.c | 548 --------------------------------------------------------------- 1 file changed, 548 deletions(-) delete mode 100644 rbtree.c (limited to 'rbtree.c') diff --git a/rbtree.c b/rbtree.c deleted file mode 100644 index 92590a57..00000000 --- a/rbtree.c +++ /dev/null @@ -1,548 +0,0 @@ -/* - Red Black Trees - (C) 1999 Andrea Arcangeli - (C) 2002 David Woodhouse - (C) 2012 Michel Lespinasse - - This program 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 2 of the License, or - (at your option) any later version. - - This program 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, write to the Free Software - Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - - linux/lib/rbtree.c -*/ - -#include "rbtree_augmented.h" - -/* - * red-black trees properties: http://en.wikipedia.org/wiki/Rbtree - * - * 1) A node is either red or black - * 2) The root is black - * 3) All leaves (NULL) are black - * 4) Both children of every red node are black - * 5) Every simple path from root to leaves contains the same number - * of black nodes. - * - * 4 and 5 give the O(log n) guarantee, since 4 implies you cannot have two - * consecutive red nodes in a path and every red node is therefore followed by - * a black. So if B is the number of black nodes on every simple path (as per - * 5), then the longest possible path due to 4 is 2B. - * - * We shall indicate color with case, where black nodes are uppercase and red - * nodes will be lowercase. Unknown color nodes shall be drawn as red within - * parentheses and have some accompanying text comment. - */ - -static inline void rb_set_black(struct rb_node *rb) -{ - rb->__rb_parent_color |= RB_BLACK; -} - -static inline struct rb_node *rb_red_parent(struct rb_node *red) -{ - return (struct rb_node *)red->__rb_parent_color; -} - -/* - * Helper function for rotations: - * - old's parent and color get assigned to new - * - old gets assigned new as a parent and 'color' as a color. - */ -static inline void -__rb_rotate_set_parents(struct rb_node *old, struct rb_node *new, - struct rb_root *root, int color) -{ - struct rb_node *parent = rb_parent(old); - new->__rb_parent_color = old->__rb_parent_color; - rb_set_parent_color(old, new, color); - __rb_change_child(old, new, parent, root); -} - -static __always_inline void -__rb_insert(struct rb_node *node, struct rb_root *root, - void (*augment_rotate)(struct rb_node *old, struct rb_node *new)) -{ - struct rb_node *parent = rb_red_parent(node), *gparent, *tmp; - - while (true) { - /* - * Loop invariant: node is red - * - * If there is a black parent, we are done. - * Otherwise, take some corrective action as we don't - * want a red root or two consecutive red nodes. - */ - if (!parent) { - rb_set_parent_color(node, NULL, RB_BLACK); - break; - } else if (rb_is_black(parent)) - break; - - gparent = rb_red_parent(parent); - - tmp = gparent->rb_right; - if (parent != tmp) { /* parent == gparent->rb_left */ - if (tmp && rb_is_red(tmp)) { - /* - * Case 1 - color flips - * - * G g - * / \ / \ - * p u --> P U - * / / - * n n - * - * However, since g's parent might be red, and - * 4) does not allow this, we need to recurse - * at g. - */ - rb_set_parent_color(tmp, gparent, RB_BLACK); - rb_set_parent_color(parent, gparent, RB_BLACK); - node = gparent; - parent = rb_parent(node); - rb_set_parent_color(node, parent, RB_RED); - continue; - } - - tmp = parent->rb_right; - if (node == tmp) { - /* - * Case 2 - left rotate at parent - * - * G G - * / \ / \ - * p U --> n U - * \ / - * n p - * - * This still leaves us in violation of 4), the - * continuation into Case 3 will fix that. - */ - parent->rb_right = tmp = node->rb_left; - node->rb_left = parent; - if (tmp) - rb_set_parent_color(tmp, parent, - RB_BLACK); - rb_set_parent_color(parent, node, RB_RED); - augment_rotate(parent, node); - parent = node; - tmp = node->rb_right; - } - - /* - * Case 3 - right rotate at gparent - * - * G P - * / \ / \ - * p U --> n g - * / \ - * n U - */ - gparent->rb_left = tmp; /* == parent->rb_right */ - parent->rb_right = gparent; - if (tmp) - rb_set_parent_color(tmp, gparent, RB_BLACK); - __rb_rotate_set_parents(gparent, parent, root, RB_RED); - augment_rotate(gparent, parent); - break; - } else { - tmp = gparent->rb_left; - if (tmp && rb_is_red(tmp)) { - /* Case 1 - color flips */ - rb_set_parent_color(tmp, gparent, RB_BLACK); - rb_set_parent_color(parent, gparent, RB_BLACK); - node = gparent; - parent = rb_parent(node); - rb_set_parent_color(node, parent, RB_RED); - continue; - } - - tmp = parent->rb_left; - if (node == tmp) { - /* Case 2 - right rotate at parent */ - parent->rb_left = tmp = node->rb_right; - node->rb_right = parent; - if (tmp) - rb_set_parent_color(tmp, parent, - RB_BLACK); - rb_set_parent_color(parent, node, RB_RED); - augment_rotate(parent, node); - parent = node; - tmp = node->rb_left; - } - - /* Case 3 - left rotate at gparent */ - gparent->rb_right = tmp; /* == parent->rb_left */ - parent->rb_left = gparent; - if (tmp) - rb_set_parent_color(tmp, gparent, RB_BLACK); - __rb_rotate_set_parents(gparent, parent, root, RB_RED); - augment_rotate(gparent, parent); - break; - } - } -} - -/* - * Inline version for rb_erase() use - we want to be able to inline - * and eliminate the dummy_rotate callback there - */ -static __always_inline void -____rb_erase_color(struct rb_node *parent, struct rb_root *root, - void (*augment_rotate)(struct rb_node *old, struct rb_node *new)) -{ - struct rb_node *node = NULL, *sibling, *tmp1, *tmp2; - - while (true) { - /* - * Loop invariants: - * - node is black (or NULL on first iteration) - * - node is not the root (parent is not NULL) - * - All leaf paths going through parent and node have a - * black node count that is 1 lower than other leaf paths. - */ - sibling = parent->rb_right; - if (node != sibling) { /* node == parent->rb_left */ - if (rb_is_red(sibling)) { - /* - * Case 1 - left rotate at parent - * - * P S - * / \ / \ - * N s --> p Sr - * / \ / \ - * Sl Sr N Sl - */ - parent->rb_right = tmp1 = sibling->rb_left; - sibling->rb_left = parent; - rb_set_parent_color(tmp1, parent, RB_BLACK); - __rb_rotate_set_parents(parent, sibling, root, - RB_RED); - augment_rotate(parent, sibling); - sibling = tmp1; - } - tmp1 = sibling->rb_right; - if (!tmp1 || rb_is_black(tmp1)) { - tmp2 = sibling->rb_left; - if (!tmp2 || rb_is_black(tmp2)) { - /* - * Case 2 - sibling color flip - * (p could be either color here) - * - * (p) (p) - * / \ / \ - * N S --> N s - * / \ / \ - * Sl Sr Sl Sr - * - * This leaves us violating 5) which - * can be fixed by flipping p to black - * if it was red, or by recursing at p. - * p is red when coming from Case 1. - */ - rb_set_parent_color(sibling, parent, - RB_RED); - if (rb_is_red(parent)) - rb_set_black(parent); - else { - node = parent; - parent = rb_parent(node); - if (parent) - continue; - } - break; - } - /* - * Case 3 - right rotate at sibling - * (p could be either color here) - * - * (p) (p) - * / \ / \ - * N S --> N Sl - * / \ \ - * sl Sr s - * \ - * Sr - */ - sibling->rb_left = tmp1 = tmp2->rb_right; - tmp2->rb_right = sibling; - parent->rb_right = tmp2; - if (tmp1) - rb_set_parent_color(tmp1, sibling, - RB_BLACK); - augment_rotate(sibling, tmp2); - tmp1 = sibling; - sibling = tmp2; - } - /* - * Case 4 - left rotate at parent + color flips - * (p and sl could be either color here. - * After rotation, p becomes black, s acquires - * p's color, and sl keeps its color) - * - * (p) (s) - * / \ / \ - * N S --> P Sr - * / \ / \ - * (sl) sr N (sl) - */ - parent->rb_right = tmp2 = sibling->rb_left; - sibling->rb_left = parent; - rb_set_parent_color(tmp1, sibling, RB_BLACK); - if (tmp2) - rb_set_parent(tmp2, parent); - __rb_rotate_set_parents(parent, sibling, root, - RB_BLACK); - augment_rotate(parent, sibling); - break; - } else { - sibling = parent->rb_left; - if (rb_is_red(sibling)) { - /* Case 1 - right rotate at parent */ - parent->rb_left = tmp1 = sibling->rb_right; - sibling->rb_right = parent; - rb_set_parent_color(tmp1, parent, RB_BLACK); - __rb_rotate_set_parents(parent, sibling, root, - RB_RED); - augment_rotate(parent, sibling); - sibling = tmp1; - } - tmp1 = sibling->rb_left; - if (!tmp1 || rb_is_black(tmp1)) { - tmp2 = sibling->rb_right; - if (!tmp2 || rb_is_black(tmp2)) { - /* Case 2 - sibling color flip */ - rb_set_parent_color(sibling, parent, - RB_RED); - if (rb_is_red(parent)) - rb_set_black(parent); - else { - node = parent; - parent = rb_parent(node); - if (parent) - continue; - } - break; - } - /* Case 3 - right rotate at sibling */ - sibling->rb_right = tmp1 = tmp2->rb_left; - tmp2->rb_left = sibling; - parent->rb_left = tmp2; - if (tmp1) - rb_set_parent_color(tmp1, sibling, - RB_BLACK); - augment_rotate(sibling, tmp2); - tmp1 = sibling; - sibling = tmp2; - } - /* Case 4 - left rotate at parent + color flips */ - parent->rb_left = tmp2 = sibling->rb_right; - sibling->rb_right = parent; - rb_set_parent_color(tmp1, sibling, RB_BLACK); - if (tmp2) - rb_set_parent(tmp2, parent); - __rb_rotate_set_parents(parent, sibling, root, - RB_BLACK); - augment_rotate(parent, sibling); - break; - } - } -} - -/* Non-inline version for rb_erase_augmented() use */ -void __rb_erase_color(struct rb_node *parent, struct rb_root *root, - void (*augment_rotate)(struct rb_node *old, struct rb_node *new)) -{ - ____rb_erase_color(parent, root, augment_rotate); -} - -/* - * Non-augmented rbtree manipulation functions. - * - * We use dummy augmented callbacks here, and have the compiler optimize them - * out of the rb_insert_color() and rb_erase() function definitions. - */ - -static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {} -static inline void dummy_copy(struct rb_node *old, struct rb_node *new) {} -static inline void dummy_rotate(struct rb_node *old, struct rb_node *new) {} - -static const struct rb_augment_callbacks dummy_callbacks = { - dummy_propagate, dummy_copy, dummy_rotate -}; - -void rb_insert_color(struct rb_node *node, struct rb_root *root) -{ - __rb_insert(node, root, dummy_rotate); -} - -void rb_erase(struct rb_node *node, struct rb_root *root) -{ - struct rb_node *rebalance; - rebalance = __rb_erase_augmented(node, root, &dummy_callbacks); - if (rebalance) - ____rb_erase_color(rebalance, root, dummy_rotate); -} - -/* - * Augmented rbtree manipulation functions. - * - * This instantiates the same __always_inline functions as in the non-augmented - * case, but this time with user-defined callbacks. - */ - -void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, - void (*augment_rotate)(struct rb_node *old, struct rb_node *new)) -{ - __rb_insert(node, root, augment_rotate); -} - -/* - * This function returns the first node (in sort order) of the tree. - */ -struct rb_node *rb_first(const struct rb_root *root) -{ - struct rb_node *n; - - n = root->rb_node; - if (!n) - return NULL; - while (n->rb_left) - n = n->rb_left; - return n; -} - -struct rb_node *rb_last(const struct rb_root *root) -{ - struct rb_node *n; - - n = root->rb_node; - if (!n) - return NULL; - while (n->rb_right) - n = n->rb_right; - return n; -} - -struct rb_node *rb_next(const struct rb_node *node) -{ - struct rb_node *parent; - - if (RB_EMPTY_NODE(node)) - return NULL; - - /* - * If we have a right-hand child, go down and then left as far - * as we can. - */ - if (node->rb_right) { - node = node->rb_right; - while (node->rb_left) - node=node->rb_left; - return (struct rb_node *)node; - } - - /* - * No right-hand children. Everything down and left is smaller than us, - * so any 'next' node must be in the general direction of our parent. - * Go up the tree; any time the ancestor is a right-hand child of its - * parent, keep going up. First time it's a left-hand child of its - * parent, said parent is our 'next' node. - */ - while ((parent = rb_parent(node)) && node == parent->rb_right) - node = parent; - - return parent; -} - -struct rb_node *rb_prev(const struct rb_node *node) -{ - struct rb_node *parent; - - if (RB_EMPTY_NODE(node)) - return NULL; - - /* - * If we have a left-hand child, go down and then right as far - * as we can. - */ - if (node->rb_left) { - node = node->rb_left; - while (node->rb_right) - node=node->rb_right; - return (struct rb_node *)node; - } - - /* - * No left-hand children. Go up till we find an ancestor which - * is a right-hand child of its parent. - */ - while ((parent = rb_parent(node)) && node == parent->rb_left) - node = parent; - - return parent; -} - -void rb_replace_node(struct rb_node *victim, struct rb_node *new, - struct rb_root *root) -{ - struct rb_node *parent = rb_parent(victim); - - /* Set the surrounding nodes to point to the replacement */ - __rb_change_child(victim, new, parent, root); - if (victim->rb_left) - rb_set_parent(victim->rb_left, new); - if (victim->rb_right) - rb_set_parent(victim->rb_right, new); - - /* Copy the pointers/colour from the victim to the replacement */ - *new = *victim; -} - -static struct rb_node *rb_left_deepest_node(const struct rb_node *node) -{ - for (;;) { - if (node->rb_left) - node = node->rb_left; - else if (node->rb_right) - node = node->rb_right; - else - return (struct rb_node *)node; - } -} - -struct rb_node *rb_next_postorder(const struct rb_node *node) -{ - const struct rb_node *parent; - if (!node) - return NULL; - parent = rb_parent(node); - - /* If we're sitting on node, we've already seen our children */ - if (parent && node == parent->rb_left && parent->rb_right) { - /* If we are the parent's left node, go to the parent's right - * node then all the way down to the left */ - return rb_left_deepest_node(parent->rb_right); - } else - /* Otherwise we are the parent's right node, and the parent - * should be next */ - return (struct rb_node *)parent; -} - -struct rb_node *rb_first_postorder(const struct rb_root *root) -{ - if (!root->rb_node) - return NULL; - - return rb_left_deepest_node(root->rb_node); -} -- cgit v1.2.3