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  • linux内核-红黑树

    //rbtree.h

    /*
      Red Black Trees
      (C) 1999  Andrea Arcangeli <andrea@suse.de>
     
      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/include/linux/rbtree.h

      To use rbtrees you'll have to implement your own insert and search cores.
      This will avoid us to use callbacks and to drop drammatically performances.
      I know it's not the cleaner way,  but in C (not in C++) to get
      performances and genericity...

      Some example of insert and search follows here. The search is a plain
      normal search over an ordered tree. The insert instead must be implemented
      in two steps: First, the code must insert the element in order as a red leaf
      in the tree, and then the support library function rb_insert_color() must
      be called. Such function will do the not trivial work to rebalance the
      rbtree, if necessary.

    -----------------------------------------------------------------------
    static inline struct page * rb_search_page_cache(struct inode * inode,
                             unsigned long offset)
    {
        struct rb_node * n = inode->i_rb_page_cache.rb_node;
        struct page * page;

        while (n)
        {
            page = rb_entry(n, struct page, rb_page_cache);

            if (offset < page->offset)
                n = n->rb_left;
            else if (offset > page->offset)
                n = n->rb_right;
            else
                return page;
        }
        return NULL;
    }

    static inline struct page * __rb_insert_page_cache(struct inode * inode,
                               unsigned long offset,
                               struct rb_node * node)
    {
        struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
        struct rb_node * parent = NULL;
        struct page * page;

        while (*p)
        {
            parent = *p;
            page = rb_entry(parent, struct page, rb_page_cache);

            if (offset < page->offset)
                p = &(*p)->rb_left;
            else if (offset > page->offset)
                p = &(*p)->rb_right;
            else
                return page;
        }

        rb_link_node(node, parent, p);

        return NULL;
    }

    static inline struct page * rb_insert_page_cache(struct inode * inode,
                             unsigned long offset,
                             struct rb_node * node)
    {
        struct page * ret;
        if ((ret = __rb_insert_page_cache(inode, offset, node)))
            goto out;
        rb_insert_color(node, &inode->i_rb_page_cache);
    out:
        return ret;
    }
    -----------------------------------------------------------------------
    */

    #ifndef    _SLINUX_RBTREE_H
    #define    _SLINUX_RBTREE_H

    #include <stdio.h>
    //#include <linux/kernel.h>
    //#include <linux/stddef.h>

    struct rb_node
    {
        unsigned long  rb_parent_color;
    #define    RB_RED        0
    #define    RB_BLACK    1
        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_color(r)   ((r)->rb_parent_color & 1)
    #define rb_is_red(r)   (!rb_color(r))
    #define rb_is_black(r) rb_color(r)
    #define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
    #define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)

    static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
    {
        rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
    }
    static inline void rb_set_color(struct rb_node *rb, int color)
    {
        rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
    }

    #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

    #define container_of(ptr, type, member) ({         
        const typeof( ((type *)0)->member ) *__mptr = (ptr);   
        (type *)( (char *)__mptr - offsetof(type,member) );})

    #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)
    #define RB_EMPTY_NODE(node)    (rb_parent(node) == node)
    #define RB_CLEAR_NODE(node)    (rb_set_parent(node, node))

    static inline void rb_init_node(struct rb_node *rb)
    {
        rb->rb_parent_color = 0;
        rb->rb_right = NULL;
        rb->rb_left = NULL;
        RB_CLEAR_NODE(rb);
    }

    extern void rb_insert_color(struct rb_node *, struct rb_root *);
    extern void rb_erase(struct rb_node *, struct rb_root *);

    typedef void (*rb_augment_f)(struct rb_node *node, void *data);

    extern void rb_augment_insert(struct rb_node *node,
                      rb_augment_f func, void *data);
    extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
    extern void rb_augment_erase_end(struct rb_node *node,
                     rb_augment_f func, void *data);

    /* 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 *);

    /* Fast replacement of a single node without remove/rebalance/add/rebalance */
    extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
                    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;
    }

    #endif    /* _LINUX_RBTREE_H */

    //rbtree.c

    /*
      Red Black Trees
      (C) 1999  Andrea Arcangeli <andrea@suse.de>
      (C) 2002  David Woodhouse <dwmw2@infradead.org>
     
      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.h"

    static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
    {
        struct rb_node *right = node->rb_right;
        struct rb_node *parent = rb_parent(node);

        if ((node->rb_right = right->rb_left))
            rb_set_parent(right->rb_left, node);
        right->rb_left = node;

        rb_set_parent(right, parent);

        if (parent)
        {
            if (node == parent->rb_left)
                parent->rb_left = right;
            else
                parent->rb_right = right;
        }
        else
            root->rb_node = right;
        rb_set_parent(node, right);
    }

    static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
    {
        struct rb_node *left = node->rb_left;
        struct rb_node *parent = rb_parent(node);

        if ((node->rb_left = left->rb_right))
            rb_set_parent(left->rb_right, node);
        left->rb_right = node;

        rb_set_parent(left, parent);

        if (parent)
        {
            if (node == parent->rb_right)
                parent->rb_right = left;
            else
                parent->rb_left = left;
        }
        else
            root->rb_node = left;
        rb_set_parent(node, left);
    }

    void rb_insert_color(struct rb_node *node, struct rb_root *root)
    {
        struct rb_node *parent, *gparent;

        while ((parent = rb_parent(node)) && rb_is_red(parent))
        {
            gparent = rb_parent(parent);

            if (parent == gparent->rb_left)
            {
                {
                    register struct rb_node *uncle = gparent->rb_right;
                    if (uncle && rb_is_red(uncle))
                    {
                        rb_set_black(uncle);
                        rb_set_black(parent);
                        rb_set_red(gparent);
                        node = gparent;
                        continue;
                    }
                }

                if (parent->rb_right == node)
                {
                    register struct rb_node *tmp;
                    __rb_rotate_left(parent, root);
                    tmp = parent;
                    parent = node;
                    node = tmp;
                }

                rb_set_black(parent);
                rb_set_red(gparent);
                __rb_rotate_right(gparent, root);
            } else {
                {
                    register struct rb_node *uncle = gparent->rb_left;
                    if (uncle && rb_is_red(uncle))
                    {
                        rb_set_black(uncle);
                        rb_set_black(parent);
                        rb_set_red(gparent);
                        node = gparent;
                        continue;
                    }
                }

                if (parent->rb_left == node)
                {
                    register struct rb_node *tmp;
                    __rb_rotate_right(parent, root);
                    tmp = parent;
                    parent = node;
                    node = tmp;
                }

                rb_set_black(parent);
                rb_set_red(gparent);
                __rb_rotate_left(gparent, root);
            }
        }

        rb_set_black(root->rb_node);
    }

    static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
                     struct rb_root *root)
    {
        struct rb_node *other;

        while ((!node || rb_is_black(node)) && node != root->rb_node)
        {
            if (parent->rb_left == node)
            {
                other = parent->rb_right;
                if (rb_is_red(other))
                {
                    rb_set_black(other);
                    rb_set_red(parent);
                    __rb_rotate_left(parent, root);
                    other = parent->rb_right;
                }
                if ((!other->rb_left || rb_is_black(other->rb_left)) &&
                    (!other->rb_right || rb_is_black(other->rb_right)))
                {
                    rb_set_red(other);
                    node = parent;
                    parent = rb_parent(node);
                }
                else
                {
                    if (!other->rb_right || rb_is_black(other->rb_right))
                    {
                        rb_set_black(other->rb_left);
                        rb_set_red(other);
                        __rb_rotate_right(other, root);
                        other = parent->rb_right;
                    }
                    rb_set_color(other, rb_color(parent));
                    rb_set_black(parent);
                    rb_set_black(other->rb_right);
                    __rb_rotate_left(parent, root);
                    node = root->rb_node;
                    break;
                }
            }
            else
            {
                other = parent->rb_left;
                if (rb_is_red(other))
                {
                    rb_set_black(other);
                    rb_set_red(parent);
                    __rb_rotate_right(parent, root);
                    other = parent->rb_left;
                }
                if ((!other->rb_left || rb_is_black(other->rb_left)) &&
                    (!other->rb_right || rb_is_black(other->rb_right)))
                {
                    rb_set_red(other);
                    node = parent;
                    parent = rb_parent(node);
                }
                else
                {
                    if (!other->rb_left || rb_is_black(other->rb_left))
                    {
                        rb_set_black(other->rb_right);
                        rb_set_red(other);
                        __rb_rotate_left(other, root);
                        other = parent->rb_left;
                    }
                    rb_set_color(other, rb_color(parent));
                    rb_set_black(parent);
                    rb_set_black(other->rb_left);
                    __rb_rotate_right(parent, root);
                    node = root->rb_node;
                    break;
                }
            }
        }
        if (node)
            rb_set_black(node);
    }

    void rb_erase(struct rb_node *node, struct rb_root *root)
    {
        struct rb_node *child, *parent;
        int color;

        if (!node->rb_left)
            child = node->rb_right;
        else if (!node->rb_right)
            child = node->rb_left;
        else
        {
            struct rb_node *old = node, *left;

            node = node->rb_right;
            while ((left = node->rb_left) != NULL)
                node = left;

            if (rb_parent(old)) {
                if (rb_parent(old)->rb_left == old)
                    rb_parent(old)->rb_left = node;
                else
                    rb_parent(old)->rb_right = node;
            } else
                root->rb_node = node;

            child = node->rb_right;
            parent = rb_parent(node);
            color = rb_color(node);

            if (parent == old) {
                parent = node;
            } else {
                if (child)
                    rb_set_parent(child, parent);
                parent->rb_left = child;

                node->rb_right = old->rb_right;
                rb_set_parent(old->rb_right, node);
            }

            node->rb_parent_color = old->rb_parent_color;
            node->rb_left = old->rb_left;
            rb_set_parent(old->rb_left, node);

            goto color;
        }

        parent = rb_parent(node);
        color = rb_color(node);

        if (child)
            rb_set_parent(child, parent);
        if (parent)
        {
            if (parent->rb_left == node)
                parent->rb_left = child;
            else
                parent->rb_right = child;
        }
        else
            root->rb_node = child;

    color:
        if (color == RB_BLACK)
            __rb_erase_color(child, parent, root);
    }

    static void rb_augment_path(struct rb_node *node, rb_augment_f func, void *data)
    {
        struct rb_node *parent;

    up:
        func(node, data);
        parent = rb_parent(node);
        if (!parent)
            return;

        if (node == parent->rb_left && parent->rb_right)
            func(parent->rb_right, data);
        else if (parent->rb_left)
            func(parent->rb_left, data);

        node = parent;
        goto up;
    }

    /*
    * after inserting @node into the tree, update the tree to account for
    * both the new entry and any damage done by rebalance
    */
    void rb_augment_insert(struct rb_node *node, rb_augment_f func, void *data)
    {
        if (node->rb_left)
            node = node->rb_left;
        else if (node->rb_right)
            node = node->rb_right;

        rb_augment_path(node, func, data);
    }

    /*
    * before removing the node, find the deepest node on the rebalance path
    * that will still be there after @node gets removed
    */
    struct rb_node *rb_augment_erase_begin(struct rb_node *node)
    {
        struct rb_node *deepest;

        if (!node->rb_right && !node->rb_left)
            deepest = rb_parent(node);
        else if (!node->rb_right)
            deepest = node->rb_left;
        else if (!node->rb_left)
            deepest = node->rb_right;
        else {
            deepest = rb_next(node);
            if (deepest->rb_right)
                deepest = deepest->rb_right;
            else if (rb_parent(deepest) != node)
                deepest = rb_parent(deepest);
        }

        return deepest;
    }

    /*
    * after removal, update the tree to account for the removed entry
    * and any rebalance damage.
    */
    void rb_augment_erase_end(struct rb_node *node, rb_augment_f func, void *data)
    {
        if (node)
            rb_augment_path(node, func, data);
    }

    /*
    * 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_parent(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_parent(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 */
        if (parent) {
            if (victim == parent->rb_left)
                parent->rb_left = new;
            else
                parent->rb_right = new;
        } else {
            root->rb_node = new;
        }
        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;
    }

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  • 原文地址:https://www.cnblogs.com/lucas-hsueh/p/3734082.html
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