diff options
Diffstat (limited to 'kern')
| -rw-r--r-- | kern/list.h | 349 | ||||
| -rw-r--r-- | kern/macro_help.h | 4 | ||||
| -rw-r--r-- | kern/rbtree.c | 478 | ||||
| -rw-r--r-- | kern/rbtree.h | 298 | ||||
| -rw-r--r-- | kern/rbtree_i.h | 179 |
5 files changed, 1306 insertions, 2 deletions
diff --git a/kern/list.h b/kern/list.h new file mode 100644 index 0000000..de7d115 --- /dev/null +++ b/kern/list.h @@ -0,0 +1,349 @@ +/* + * Copyright (c) 2009, 2010 Richard Braun. + * + * 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef _KERN_LIST_H +#define _KERN_LIST_H + +#include <stddef.h> +#include <sys/types.h> + +#define structof(ptr, type, member) \ + ((type *)((char *)ptr - offsetof(type, member))) + +/* + * Structure used as both head and node. + * + * This implementation relies on using the same type for both heads and nodes. + * + * It is recommended to encode the use of struct list variables in their names, + * e.g. struct list free_list or struct list free_objects is a good hint for a + * list of free objects. A declaration like struct list free_node clearly + * indicates it is used as part of a node in the free list. + */ +struct list { + struct list *prev; + struct list *next; +}; + +/* + * Static list initializer. + */ +#define LIST_INITIALIZER(list) { &(list), &(list) } + +/* + * Initialize a list. + */ +static inline void list_init(struct list *list) +{ + list->prev = list; + list->next = list; +} + +/* + * Initialize a list node. + * + * An entry is in no list when its node members point to NULL. + */ +static inline void list_node_init(struct list *node) +{ + node->prev = NULL; + node->next = NULL; +} + +/* + * Return true if node is in no list. + */ +static inline int list_node_unlinked(const struct list *node) +{ + return node->prev == NULL; +} + +/* + * Macro that evaluates to the address of the structure containing the + * given node based on the given type and member. + */ +#define list_entry(node, type, member) structof(node, type, member) + +/* + * Return the first node of a list. + */ +static inline struct list * list_first(const struct list *list) +{ + return list->next; +} + +/* + * Return the last node of a list. + */ +static inline struct list * list_last(const struct list *list) +{ + return list->prev; +} + +/* + * Return the node next to the given node. + */ +static inline struct list * list_next(const struct list *node) +{ + return node->next; +} + +/* + * Return the node previous to the given node. + */ +static inline struct list * list_prev(const struct list *node) +{ + return node->prev; +} + +/* + * Get the first entry of a list. + */ +#define list_first_entry(list, type, member) \ + list_entry(list_first(list), type, member) + +/* + * Get the last entry of a list. + */ +#define list_last_entry(list, type, member) \ + list_entry(list_last(list), type, member) + +/* + * Return true if node is after the last or before the first node of the list. + */ +static inline int list_end(const struct list *list, const struct list *node) +{ + return list == node; +} + +/* + * Return true if list is empty. + */ +static inline int list_empty(const struct list *list) +{ + return list == list->next; +} + +/* + * Return true if list contains exactly one node. + */ +static inline int list_singular(const struct list *list) +{ + return (list != list->next) && (list->next == list->prev); +} + +/* + * Split list2 by moving its nodes up to (but not including) the given + * node into list1 (which can be in a stale state). + * + * If list2 is empty, or node is list2 or list2->next, nothing is done. + */ +static inline void list_split(struct list *list1, struct list *list2, + struct list *node) +{ + if (list_empty(list2) || (list2->next == node) || list_end(list2, node)) + return; + + list1->next = list2->next; + list1->next->prev = list1; + + list1->prev = node->prev; + node->prev->next = list1; + + list2->next = node; + node->prev = list2; +} + +/* + * Append the nodes of list2 at the end of list1. + * + * After completion, list2 is stale. + */ +static inline void list_concat(struct list *list1, const struct list *list2) +{ + struct list *last1, *first2, *last2; + + if (list_empty(list2)) + return; + + last1 = list1->prev; + first2 = list2->next; + last2 = list2->prev; + + last1->next = first2; + first2->prev = last1; + + last2->next = list1; + list1->prev = last2; +} + +/* + * Set the new head of a list. + * + * This function is an optimized version of : + * list_init(&new_list); + * list_concat(&new_list, &old_list); + * + * After completion, old_head is stale. + */ +static inline void list_set_head(struct list *new_head, + const struct list *old_head) +{ + if (list_empty(old_head)) { + list_init(new_head); + return; + } + + *new_head = *old_head; + new_head->next->prev = new_head; + new_head->prev->next = new_head; +} + +/* + * Add a node between two nodes. + */ +static inline void list_add(struct list *prev, struct list *next, + struct list *node) +{ + next->prev = node; + node->next = next; + + prev->next = node; + node->prev = prev; +} + +/* + * Insert a node at the head of a list. + */ +static inline void list_insert(struct list *list, struct list *node) +{ + list_add(list, list->next, node); +} + +/* + * Insert a node at the tail of a list. + */ +static inline void list_insert_tail(struct list *list, struct list *node) +{ + list_add(list->prev, list, node); +} + +/* + * Insert a node before another node. + */ +static inline void list_insert_before(struct list *next, struct list *node) +{ + list_add(next->prev, next, node); +} + +/* + * Insert a node after another node. + */ +static inline void list_insert_after(struct list *prev, struct list *node) +{ + list_add(prev, prev->next, node); +} + +/* + * Remove a node from a list. + * + * After completion, the node is stale. + */ +static inline void list_remove(struct list *node) +{ + node->prev->next = node->next; + node->next->prev = node->prev; +} + +/* + * Forge a loop to process all nodes of a list. + * + * The node must not be altered during the loop. + */ +#define list_for_each(list, node) \ +for (node = list_first(list); \ + !list_end(list, node); \ + node = list_next(node)) + +/* + * Forge a loop to process all nodes of a list. + */ +#define list_for_each_safe(list, node, tmp) \ +for (node = list_first(list), tmp = list_next(node); \ + !list_end(list, node); \ + node = tmp, tmp = list_next(node)) + +/* + * Version of list_for_each() that processes nodes backward. + */ +#define list_for_each_reverse(list, node) \ +for (node = list_last(list); \ + !list_end(list, node); \ + node = list_prev(node)) + +/* + * Version of list_for_each_safe() that processes nodes backward. + */ +#define list_for_each_reverse_safe(list, node, tmp) \ +for (node = list_last(list), tmp = list_prev(node); \ + !list_end(list, node); \ + node = tmp, tmp = list_prev(node)) + +/* + * Forge a loop to process all entries of a list. + * + * The entry node must not be altered during the loop. + */ +#define list_for_each_entry(list, entry, member) \ +for (entry = list_entry(list_first(list), typeof(*entry), member); \ + !list_end(list, &entry->member); \ + entry = list_entry(list_next(&entry->member), typeof(*entry), \ + member)) + +/* + * Forge a loop to process all entries of a list. + */ +#define list_for_each_entry_safe(list, entry, tmp, member) \ +for (entry = list_entry(list_first(list), typeof(*entry), member), \ + tmp = list_entry(list_next(&entry->member), typeof(*entry), \ + member); \ + !list_end(list, &entry->member); \ + entry = tmp, tmp = list_entry(list_next(&entry->member), \ + typeof(*entry), member)) + +/* + * Version of list_for_each_entry() that processes entries backward. + */ +#define list_for_each_entry_reverse(list, entry, member) \ +for (entry = list_entry(list_last(list), typeof(*entry), member); \ + !list_end(list, &entry->member); \ + entry = list_entry(list_prev(&entry->member), typeof(*entry), \ + member)) + +/* + * Version of list_for_each_entry_safe() that processes entries backward. + */ +#define list_for_each_entry_reverse_safe(list, entry, tmp, member) \ +for (entry = list_entry(list_last(list), typeof(*entry), member), \ + tmp = list_entry(list_prev(&entry->member), typeof(*entry), \ + member); \ + !list_end(list, &entry->member); \ + entry = tmp, tmp = list_entry(list_prev(&entry->member), \ + typeof(*entry), member)) + +#endif /* _KERN_LIST_H */ diff --git a/kern/macro_help.h b/kern/macro_help.h index e13b01d..a3d156b 100644 --- a/kern/macro_help.h +++ b/kern/macro_help.h @@ -45,8 +45,8 @@ boolean_t ALWAYS; #define ALWAYS TRUE #endif /* lint */ -#define MACRO_BEGIN do { -#define MACRO_END } while (NEVER) +#define MACRO_BEGIN ({ +#define MACRO_END }) #define MACRO_RETURN if (ALWAYS) return diff --git a/kern/rbtree.c b/kern/rbtree.c new file mode 100644 index 0000000..1c04c5c --- /dev/null +++ b/kern/rbtree.c @@ -0,0 +1,478 @@ +/* + * Copyright (c) 2010 Richard Braun. + * + * 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <kern/assert.h> +#include <kern/rbtree.h> +#include <kern/rbtree_i.h> +#include <sys/types.h> + +#define unlikely(expr) __builtin_expect(!!(expr), 0) + +/* + * Return the index of a node in the children array of its parent. + * + * The parent parameter must not be null, and must be the parent of the + * given node. + */ +static inline int rbtree_index(const struct rbtree_node *node, + const struct rbtree_node *parent) +{ + assert(parent != NULL); + assert((node == NULL) || (rbtree_parent(node) == parent)); + + if (parent->children[RBTREE_LEFT] == node) + return RBTREE_LEFT; + + assert(parent->children[RBTREE_RIGHT] == node); + + return RBTREE_RIGHT; +} + +/* + * Return the color of a node. + */ +static inline int rbtree_color(const struct rbtree_node *node) +{ + return node->parent & RBTREE_COLOR_MASK; +} + +/* + * Return true if the node is red. + */ +static inline int rbtree_is_red(const struct rbtree_node *node) +{ + return rbtree_color(node) == RBTREE_COLOR_RED; +} + +/* + * Return true if the node is black. + */ +static inline int rbtree_is_black(const struct rbtree_node *node) +{ + return rbtree_color(node) == RBTREE_COLOR_BLACK; +} + +/* + * Set the parent of a node, retaining its current color. + */ +static inline void rbtree_set_parent(struct rbtree_node *node, + struct rbtree_node *parent) +{ + assert(rbtree_check_alignment(node)); + assert(rbtree_check_alignment(parent)); + + node->parent = (unsigned long)parent | (node->parent & RBTREE_COLOR_MASK); +} + +/* + * Set the color of a node, retaining its current parent. + */ +static inline void rbtree_set_color(struct rbtree_node *node, int color) +{ + assert((color & ~RBTREE_COLOR_MASK) == 0); + node->parent = (node->parent & RBTREE_PARENT_MASK) | color; +} + +/* + * Set the color of a node to red, retaining its current parent. + */ +static inline void rbtree_set_red(struct rbtree_node *node) +{ + rbtree_set_color(node, RBTREE_COLOR_RED); +} + +/* + * Set the color of a node to black, retaining its current parent. + */ +static inline void rbtree_set_black(struct rbtree_node *node) +{ + rbtree_set_color(node, RBTREE_COLOR_BLACK); +} + +/* + * Perform a tree rotation, rooted at the given node. + * + * The direction parameter defines the rotation direction and is either + * RBTREE_LEFT or RBTREE_RIGHT. + */ +static void rbtree_rotate(struct rbtree *tree, struct rbtree_node *node, + int direction) +{ + struct rbtree_node *parent, *rnode; + int left, right; + + left = direction; + right = 1 - left; + parent = rbtree_parent(node); + rnode = node->children[right]; + + node->children[right] = rnode->children[left]; + + if (rnode->children[left] != NULL) + rbtree_set_parent(rnode->children[left], node); + + rnode->children[left] = node; + rbtree_set_parent(rnode, parent); + + if (unlikely(parent == NULL)) + tree->root = rnode; + else + parent->children[rbtree_index(node, parent)] = rnode; + + rbtree_set_parent(node, rnode); +} + +void rbtree_insert_rebalance(struct rbtree *tree, struct rbtree_node *parent, + int index, struct rbtree_node *node) +{ + struct rbtree_node *grand_parent, *uncle, *tmp; + int left, right; + + assert(rbtree_check_alignment(parent)); + assert(rbtree_check_alignment(node)); + + node->parent = (unsigned long)parent | RBTREE_COLOR_RED; + node->children[RBTREE_LEFT] = NULL; + node->children[RBTREE_RIGHT] = NULL; + + if (unlikely(parent == NULL)) + tree->root = node; + else + parent->children[index] = node; + + for (;;) { + if (parent == NULL) { + rbtree_set_black(node); + break; + } + + if (rbtree_is_black(parent)) + break; + + grand_parent = rbtree_parent(parent); + assert(grand_parent != NULL); + + left = rbtree_index(parent, grand_parent); + right = 1 - left; + + uncle = grand_parent->children[right]; + + /* + * Case 1: uncle is red. Flip colors and repeat at grand parent. + */ + if ((uncle != NULL) && rbtree_is_red(uncle)) { + rbtree_set_black(uncle); + rbtree_set_black(parent); + rbtree_set_red(grand_parent); + node = grand_parent; + parent = rbtree_parent(node); + continue; + } + + /* + * Case 2: node is the right child of its parent. Rotate left at parent + * to reduce to case 3. + */ + if (parent->children[right] == node) { + rbtree_rotate(tree, parent, left); + tmp = node; + node = parent; + parent = tmp; + } + + /* + * Case 3: node is the left child of its parent. Handle colors, rotate + * right at grand parent, and leave. + */ + rbtree_set_black(parent); + rbtree_set_red(grand_parent); + rbtree_rotate(tree, grand_parent, right); + break; + } + + assert(rbtree_is_black(tree->root)); +} + +void rbtree_remove(struct rbtree *tree, struct rbtree_node *node) +{ + struct rbtree_node *child, *parent, *brother; + int color, left, right; + + if (node->children[RBTREE_LEFT] == NULL) + child = node->children[RBTREE_RIGHT]; + else if (node->children[RBTREE_RIGHT] == NULL) + child = node->children[RBTREE_LEFT]; + else { + struct rbtree_node *successor; + + /* + * Two-children case: replace the node with its successor. + */ + + successor = node->children[RBTREE_RIGHT]; + + while (successor->children[RBTREE_LEFT] != NULL) + successor = successor->children[RBTREE_LEFT]; + + color = rbtree_color(successor); + child = successor->children[RBTREE_RIGHT]; + parent = rbtree_parent(node); + + if (unlikely(parent == NULL)) + tree->root = successor; + else + parent->children[rbtree_index(node, parent)] = successor; + + parent = rbtree_parent(successor); + + /* + * Set parent directly to keep the original color. + */ + successor->parent = node->parent; + successor->children[RBTREE_LEFT] = node->children[RBTREE_LEFT]; + rbtree_set_parent(successor->children[RBTREE_LEFT], successor); + + if (node == parent) + parent = successor; + else { + successor->children[RBTREE_RIGHT] = node->children[RBTREE_RIGHT]; + rbtree_set_parent(successor->children[RBTREE_RIGHT], successor); + parent->children[RBTREE_LEFT] = child; + + if (child != NULL) + rbtree_set_parent(child, parent); + } + + goto update_color; + } + + /* + * Node has at most one child. + */ + + color = rbtree_color(node); + parent = rbtree_parent(node); + + if (child != NULL) + rbtree_set_parent(child, parent); + + if (unlikely(parent == NULL)) + tree->root = child; + else + parent->children[rbtree_index(node, parent)] = child; + + /* + * The node has been removed, update the colors. The child pointer can + * be null, in which case it is considered a black leaf. + */ +update_color: + if (color == RBTREE_COLOR_RED) + return; + + for (;;) { + if ((child != NULL) && rbtree_is_red(child)) { + rbtree_set_black(child); + break; + } + + if (parent == NULL) + break; + + left = rbtree_index(child, parent); + right = 1 - left; + + brother = parent->children[right]; + + /* + * Case 1: brother is red. Recolor and rotate left at parent so that + * brother becomes black. + */ + if (rbtree_is_red(brother)) { + rbtree_set_black(brother); + rbtree_set_red(parent); + rbtree_rotate(tree, parent, left); + brother = parent->children[right]; + } + + /* + * Case 2: brother has no red child. Recolor and repeat at parent. + */ + if (((brother->children[RBTREE_LEFT] == NULL) + || rbtree_is_black(brother->children[RBTREE_LEFT])) + && ((brother->children[RBTREE_RIGHT] == NULL) + || rbtree_is_black(brother->children[RBTREE_RIGHT]))) { + rbtree_set_red(brother); + child = parent; + parent = rbtree_parent(child); + continue; + } + + /* + * Case 3: brother's right child is black. Recolor and rotate right + * at brother to reduce to case 4. + */ + if ((brother->children[right] == NULL) + || rbtree_is_black(brother->children[right])) { + rbtree_set_black(brother->children[left]); + rbtree_set_red(brother); + rbtree_rotate(tree, brother, right); + brother = parent->children[right]; + } + + /* + * Case 4: brother's left child is black. Exchange parent and brother + * colors (we already know brother is black), set brother's right child + * black, rotate left at parent and leave. + */ + rbtree_set_color(brother, rbtree_color(parent)); + rbtree_set_black(parent); + rbtree_set_black(brother->children[right]); + rbtree_rotate(tree, parent, left); + break; + } + + assert((tree->root == NULL) || rbtree_is_black(tree->root)); +} + +struct rbtree_node * rbtree_nearest(struct rbtree_node *parent, int index, + int direction) +{ + assert(rbtree_check_index(direction)); + + if (parent == NULL) + return NULL; + + assert(rbtree_check_index(index)); + + if (index != direction) + return parent; + + return rbtree_walk(parent, direction); +} + +struct rbtree_node * rbtree_firstlast(const struct rbtree *tree, int direction) +{ + struct rbtree_node *prev, *cur; + + assert(rbtree_check_index(direction)); + + prev = NULL; + + for (cur = tree->root; cur != NULL; cur = cur->children[direction]) + prev = cur; + + return prev; +} + +struct rbtree_node * rbtree_walk(struct rbtree_node *node, int direction) +{ + int left, right; + + assert(rbtree_check_index(direction)); + + left = direction; + right = 1 - left; + + if (node == NULL) + return NULL; + + if (node->children[left] != NULL) { + node = node->children[left]; + + while (node->children[right] != NULL) + node = node->children[right]; + } else { + struct rbtree_node *parent; + int index; + + for (;;) { + parent = rbtree_parent(node); + + if (parent == NULL) + return NULL; + + index = rbtree_index(node, parent); + node = parent; + + if (index == right) + break; + } + } + + return node; +} + +/* + * Return the left-most deepest child node of the given node. + */ +static struct rbtree_node * rbtree_find_deepest(struct rbtree_node *node) +{ + struct rbtree_node *parent; + + assert(node != NULL); + + for (;;) { + parent = node; + node = node->children[RBTREE_LEFT]; + + if (node == NULL) { + node = parent->children[RBTREE_RIGHT]; + + if (node == NULL) + return parent; + } + } +} + +struct rbtree_node * rbtree_postwalk_deepest(const struct rbtree *tree) +{ + struct rbtree_node *node; + + node = tree->root; + + if (node == NULL) + return NULL; + + return rbtree_find_deepest(node); +} + +struct rbtree_node * rbtree_postwalk_unlink(struct rbtree_node *node) +{ + struct rbtree_node *parent; + int index; + + if (node == NULL) + return NULL; + + assert(node->children[RBTREE_LEFT] == NULL); + assert(node->children[RBTREE_RIGHT] == NULL); + + parent = rbtree_parent(node); + + if (parent == NULL) + return NULL; + + index = rbtree_index(node, parent); + parent->children[index] = NULL; + node = parent->children[RBTREE_RIGHT]; + + if (node == NULL) + return parent; + + return rbtree_find_deepest(node); +} diff --git a/kern/rbtree.h b/kern/rbtree.h new file mode 100644 index 0000000..b6d62bf --- /dev/null +++ b/kern/rbtree.h @@ -0,0 +1,298 @@ +/* + * Copyright (c) 2010, 2011 Richard Braun. + * + * 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef _KERN_RBTREE_H +#define _KERN_RBTREE_H + +#include <stddef.h> +#include <kern/assert.h> +#include <kern/macro_help.h> +#include <kern/rbtree.h> +#include <sys/types.h> + +#define structof(ptr, type, member) \ + ((type *)((char *)ptr - offsetof(type, member))) + +/* + * Indexes of the left and right nodes in the children array of a node. + */ +#define RBTREE_LEFT 0 +#define RBTREE_RIGHT 1 + +/* + * Red-black node. + */ +struct rbtree_node; + +/* + * Red-black tree. + */ +struct rbtree; + +/* + * Static tree initializer. + */ +#define RBTREE_INITIALIZER { NULL } + +#include "rbtree_i.h" + +/* + * Initialize a tree. + */ +static inline void rbtree_init(struct rbtree *tree) +{ + tree->root = NULL; +} + +/* + * Initialize a node. + * + * A node is in no tree when its parent points to itself. + */ +static inline void rbtree_node_init(struct rbtree_node *node) +{ + assert(rbtree_check_alignment(node)); + + node->parent = (unsigned long)node | RBTREE_COLOR_RED; + node->children[RBTREE_LEFT] = NULL; + node->children[RBTREE_RIGHT] = NULL; +} + +/* + * Return true if node is in no tree. + */ +static inline int rbtree_node_unlinked(const struct rbtree_node *node) +{ + return rbtree_parent(node) == node; +} + +/* + * Macro that evaluates to the address of the structure containing the + * given node based on the given type and member. + */ +#define rbtree_entry(node, type, member) structof(node, type, member) + +/* + * Return true if tree is empty. + */ +static inline int rbtree_empty(const struct rbtree *tree) +{ + return tree->root == NULL; +} + +/* + * Look up a node in a tree. + * + * Note that implementing the lookup algorithm as a macro gives two benefits: + * First, it avoids the overhead of a callback function. Next, the type of the + * cmp_fn parameter isn't rigid. The only guarantee offered by this + * implementation is that the key parameter is the first parameter given to + * cmp_fn. This way, users can pass only the value they need for comparison + * instead of e.g. allocating a full structure on the stack. + * + * See rbtree_insert(). + */ +#define rbtree_lookup(tree, key, cmp_fn) \ +MACRO_BEGIN \ + struct rbtree_node *cur; \ + int diff; \ + \ + cur = (tree)->root; \ + \ + while (cur != NULL) { \ + diff = cmp_fn(key, cur); \ + \ + if (diff == 0) \ + break; \ + \ + cur = cur->children[rbtree_d2i(diff)]; \ + } \ + \ + cur; \ +MACRO_END + +/* + * Look up a node or one of its nearest nodes in a tree. + * + * This macro essentially acts as rbtree_lookup() but if no entry matched + * the key, an additional step is performed to obtain the next or previous + * node, depending on the direction (left or right). + * + * The constraints that apply to the key parameter are the same as for + * rbtree_lookup(). + */ +#define rbtree_lookup_nearest(tree, key, cmp_fn, dir) \ +MACRO_BEGIN \ + struct rbtree_node *cur, *prev; \ + int diff, index; \ + \ + prev = NULL; \ + index = -1; \ + cur = (tree)->root; \ + \ + while (cur != NULL) { \ + diff = cmp_fn(key, cur); \ + \ + if (diff == 0) \ + break; \ + \ + prev = cur; \ + index = rbtree_d2i(diff); \ + cur = cur->children[index]; \ + } \ + \ + if (cur == NULL) \ + cur = rbtree_nearest(prev, index, dir); \ + \ + cur; \ +MACRO_END + +/* + * Insert a node in a tree. + * + * This macro performs a standard lookup to obtain the insertion point of + * the given node in the tree (it is assumed that the inserted node never + * compares equal to any other entry in the tree) and links the node. It + * then It then checks red-black rules violations, and rebalances the tree + * if necessary. + * + * Unlike rbtree_lookup(), the cmp_fn parameter must compare two complete + * entries, so it is suggested to use two different comparison inline + * functions, such as myobj_cmp_lookup() and myobj_cmp_insert(). There is no + * guarantee about the order of the nodes given to the comparison function. + * + * See rbtree_lookup(). + */ +#define rbtree_insert(tree, node, cmp_fn) \ +MACRO_BEGIN \ + struct rbtree_node *cur, *prev; \ + int diff, index; \ + \ + prev = NULL; \ + index = -1; \ + cur = (tree)->root; \ + \ + while (cur != NULL) { \ + diff = cmp_fn(node, cur); \ + assert(diff != 0); \ + prev = cur; \ + index = rbtree_d2i(diff); \ + cur = cur->children[index]; \ + } \ + \ + rbtree_insert_rebalance(tree, prev, index, node); \ +MACRO_END + +/* + * Look up a node/slot pair in a tree. + * + * This macro essentially acts as rbtree_lookup() but in addition to a node, + * it also returns a slot, which identifies an insertion point in the tree. + * If the returned node is null, the slot can be used by rbtree_insert_slot() + * to insert without the overhead of an additional lookup. The slot is a + * simple unsigned long integer. + * + * The constraints that apply to the key parameter are the same as for + * rbtree_lookup(). + */ +#define rbtree_lookup_slot(tree, key, cmp_fn, slot) \ +MACRO_BEGIN \ + struct rbtree_node *cur, *prev; \ + int diff, index; \ + \ + prev = NULL; \ + index = 0; \ + cur = (tree)->root; \ + \ + while (cur != NULL) { \ + diff = cmp_fn(key, cur); \ + \ + if (diff == 0) \ + break; \ + \ + prev = cur; \ + index = rbtree_d2i(diff); \ + cur = cur->children[index]; \ + } \ + \ + (slot) = rbtree_slot(prev, index); \ + cur; \ +MACRO_END + +/* + * Insert a node at an insertion point in a tree. + * + * This macro essentially acts as rbtree_insert() except that it doesn't + * obtain the insertion point with a standard lookup. The insertion point + * is obtained by calling rbtree_lookup_slot(). In addition, the new node + * must not compare equal to an existing node in the tree (i.e. the slot + * must denote a null node). + */ +#define rbtree_insert_slot(tree, slot, node) \ +MACRO_BEGIN \ + struct rbtree_node *parent; \ + int index; \ + \ + parent = rbtree_slot_parent(slot); \ + index = rbtree_slot_index(slot); \ + rbtree_insert_rebalance(tree, parent, index, node); \ +MACRO_END + +/* + * Remove a node from a tree. + * + * After completion, the node is stale. + */ +void rbtree_remove(struct rbtree *tree, struct rbtree_node *node); + +/* + * Return the first node of a tree. + */ +#define rbtree_first(tree) rbtree_firstlast(tree, RBTREE_LEFT) + +/* + * Return the last node of a tree. + */ +#define rbtree_last(tree) rbtree_firstlast(tree, RBTREE_RIGHT) + +/* + * Return the node previous to the given node. + */ +#define rbtree_prev(node) rbtree_walk(node, RBTREE_LEFT) + +/* + * Return the node next to the given node. + */ +#define rbtree_next(node) rbtree_walk(node, RBTREE_RIGHT) + +/* + * Forge a loop to process all nodes of a tree, removing them when visited. + * + * This macro can only be used to destroy a tree, so that the resources used + * by the entries can be released by the user. It basically removes all nodes + * without doing any color checking. + * + * After completion, all nodes and the tree root member are stale. + */ +#define rbtree_for_each_remove(tree, node, tmp) \ +for (node = rbtree_postwalk_deepest(tree), \ + tmp = rbtree_postwalk_unlink(node); \ + node != NULL; \ + node = tmp, tmp = rbtree_postwalk_unlink(node)) \ + +#endif /* _KERN_RBTREE_H */ diff --git a/kern/rbtree_i.h b/kern/rbtree_i.h new file mode 100644 index 0000000..9befc92 --- /dev/null +++ b/kern/rbtree_i.h @@ -0,0 +1,179 @@ +/* + * Copyright (c) 2010, 2011 Richard Braun. + * + * 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., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef _KERN_RBTREE_I_H +#define _KERN_RBTREE_I_H + +#include <kern/assert.h> + +/* + * Red-black node structure. + * + * To reduce the number of branches and the instruction cache footprint, + * the left and right child pointers are stored in an array, and the symmetry + * of most tree operations is exploited by using left/right variables when + * referring to children. + * + * In addition, this implementation assumes that all nodes are 4-byte aligned, + * so that the least significant bit of the parent member can be used to store + * the color of the node. This is true for all modern 32 and 64 bits + * architectures, as long as the nodes aren't embedded in structures with + * special alignment constraints such as member packing. + */ +struct rbtree_node { + unsigned long parent; + struct rbtree_node *children[2]; +}; + +/* + * Red-black tree structure. + */ +struct rbtree { + struct rbtree_node *root; +}; + +/* + * Masks applied on the parent member of a node to obtain either the + * color or the parent address. + */ +#define RBTREE_COLOR_MASK 0x1UL +#define RBTREE_PARENT_MASK (~0x3UL) + +/* + * Node colors. + */ +#define RBTREE_COLOR_RED 0 +#define RBTREE_COLOR_BLACK 1 + +/* + * Masks applied on slots to obtain either the child index or the parent + * address. + */ +#define RBTREE_SLOT_INDEX_MASK 0x1UL +#define RBTREE_SLOT_PARENT_MASK (~RBTREE_SLOT_INDEX_MASK) + +/* + * Return true if the given pointer is suitably aligned. + */ +static inline int rbtree_check_alignment(const struct rbtree_node *node) +{ + return ((unsigned long)node & (~RBTREE_PARENT_MASK)) == 0; +} + +/* + * Return true if the given index is a valid child index. + */ +static inline int rbtree_check_index(int index) +{ + return index == (index & 1); +} + +/* + * Convert the result of a comparison into an index in the children array + * (0 or 1). + * + * This function is mostly used when looking up a node. + */ +static inline int rbtree_d2i(int diff) +{ + return !(diff <= 0); +} + +/* + * Return the parent of a node. + */ +static inline struct rbtree_node * rbtree_parent(const struct rbtree_node *node) +{ + return (struct rbtree_node *)(node->parent & RBTREE_PARENT_MASK); +} + +/* + * Translate an insertion point into a slot. + */ +static inline unsigned long rbtree_slot(struct rbtree_node *parent, int index) +{ + assert(rbtree_check_alignment(parent)); + assert(rbtree_check_index(index)); + return (unsigned long)parent | index; +} + +/* + * Extract the parent address from a slot. + */ +static inline struct rbtree_node * rbtree_slot_parent(unsigned long slot) +{ + return (struct rbtree_node *)(slot & RBTREE_SLOT_PARENT_MASK); +} + +/* + * Extract the index from a slot. + */ +static inline int rbtree_slot_index(unsigned long slot) +{ + return slot & RBTREE_SLOT_INDEX_MASK; +} + +/* + * Insert a node in a tree, rebalancing it if necessary. + * + * The index parameter is the index in the children array of the parent where + * the new node is to be inserted. It is ignored if the parent is null. + * + * This function is intended to be used by the rbtree_insert() macro only. + */ +void rbtree_insert_rebalance(struct rbtree *tree, struct rbtree_node *parent, + int index, struct rbtree_node *node); + +/* + * Return the previous or next node relative to a location in a tree. + * + * The parent and index parameters define the location, which can be empty. + * The direction parameter is either RBTREE_LEFT (to obtain the previous + * node) or RBTREE_RIGHT (to obtain the next one). + */ +struct rbtree_node * rbtree_nearest(struct rbtree_node *parent, int index, + int direction); + +/* + * Return the first or last node of a tree. + * + * The direction parameter is either RBTREE_LEFT (to obtain the first node) + * or RBTREE_RIGHT (to obtain the last one). + */ +struct rbtree_node * rbtree_firstlast(const struct rbtree *tree, int direction); + +/* + * Return the node next to, or previous to the given node. + * + * The direction parameter is either RBTREE_LEFT (to obtain the previous node) + * or RBTREE_RIGHT (to obtain the next one). + */ +struct rbtree_node * rbtree_walk(struct rbtree_node *node, int direction); + +/* + * Return the left-most deepest node of a tree, which is the starting point of + * the postorder traversal performed by rbtree_for_each_remove(). + */ +struct rbtree_node * rbtree_postwalk_deepest(const struct rbtree *tree); + +/* + * Unlink a node from its tree and return the next (right) node in postorder. + */ +struct rbtree_node * rbtree_postwalk_unlink(struct rbtree_node *node); + +#endif /* _KERN_RBTREE_I_H */ |