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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:49:25 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 15:49:25 +0000 |
commit | 464df1d5e5ab1322e2dd0a7796939fff1aeefa9a (patch) | |
tree | 6a403684e0978f0287d7f0ec0e5aab1fd31a59e1 /lib/ext2fs/rbtree.c | |
parent | Initial commit. (diff) | |
download | e2fsprogs-464df1d5e5ab1322e2dd0a7796939fff1aeefa9a.tar.xz e2fsprogs-464df1d5e5ab1322e2dd0a7796939fff1aeefa9a.zip |
Adding upstream version 1.47.0.upstream/1.47.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/ext2fs/rbtree.c | 383 |
1 files changed, 383 insertions, 0 deletions
diff --git a/lib/ext2fs/rbtree.c b/lib/ext2fs/rbtree.c new file mode 100644 index 0000000..74426fa --- /dev/null +++ b/lib/ext2fs/rbtree.c @@ -0,0 +1,383 @@ +/* + 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 = ext2fs_rb_parent(node); + + if ((node->rb_right = right->rb_left)) + ext2fs_rb_set_parent(right->rb_left, node); + right->rb_left = node; + + ext2fs_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; + ext2fs_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 = ext2fs_rb_parent(node); + + if ((node->rb_left = left->rb_right)) + ext2fs_rb_set_parent(left->rb_right, node); + left->rb_right = node; + + ext2fs_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; + ext2fs_rb_set_parent(node, left); +} + +void ext2fs_rb_insert_color(struct rb_node *node, struct rb_root *root) +{ + struct rb_node *parent, *gparent; + + while ((parent = ext2fs_rb_parent(node)) && ext2fs_rb_is_red(parent)) + { + gparent = ext2fs_rb_parent(parent); + + if (parent == gparent->rb_left) + { + { + register struct rb_node *uncle = gparent->rb_right; + if (uncle && ext2fs_rb_is_red(uncle)) + { + ext2fs_rb_set_black(uncle); + ext2fs_rb_set_black(parent); + ext2fs_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; + } + + ext2fs_rb_set_black(parent); + ext2fs_rb_set_red(gparent); + __rb_rotate_right(gparent, root); + } else { + { + register struct rb_node *uncle = gparent->rb_left; + if (uncle && ext2fs_rb_is_red(uncle)) + { + ext2fs_rb_set_black(uncle); + ext2fs_rb_set_black(parent); + ext2fs_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; + } + + ext2fs_rb_set_black(parent); + ext2fs_rb_set_red(gparent); + __rb_rotate_left(gparent, root); + } + } + + ext2fs_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 || ext2fs_rb_is_black(node)) && node != root->rb_node) + { + if (parent->rb_left == node) + { + other = parent->rb_right; + if (ext2fs_rb_is_red(other)) + { + ext2fs_rb_set_black(other); + ext2fs_rb_set_red(parent); + __rb_rotate_left(parent, root); + other = parent->rb_right; + } + if ((!other->rb_left || ext2fs_rb_is_black(other->rb_left)) && + (!other->rb_right || ext2fs_rb_is_black(other->rb_right))) + { + ext2fs_rb_set_red(other); + node = parent; + parent = ext2fs_rb_parent(node); + } + else + { + if (!other->rb_right || ext2fs_rb_is_black(other->rb_right)) + { + ext2fs_rb_set_black(other->rb_left); + ext2fs_rb_set_red(other); + __rb_rotate_right(other, root); + other = parent->rb_right; + } + ext2fs_rb_set_color(other, ext2fs_rb_color(parent)); + ext2fs_rb_set_black(parent); + ext2fs_rb_set_black(other->rb_right); + __rb_rotate_left(parent, root); + node = root->rb_node; + break; + } + } + else + { + other = parent->rb_left; + if (ext2fs_rb_is_red(other)) + { + ext2fs_rb_set_black(other); + ext2fs_rb_set_red(parent); + __rb_rotate_right(parent, root); + other = parent->rb_left; + } + if ((!other->rb_left || ext2fs_rb_is_black(other->rb_left)) && + (!other->rb_right || ext2fs_rb_is_black(other->rb_right))) + { + ext2fs_rb_set_red(other); + node = parent; + parent = ext2fs_rb_parent(node); + } + else + { + if (!other->rb_left || ext2fs_rb_is_black(other->rb_left)) + { + ext2fs_rb_set_black(other->rb_right); + ext2fs_rb_set_red(other); + __rb_rotate_left(other, root); + other = parent->rb_left; + } + ext2fs_rb_set_color(other, ext2fs_rb_color(parent)); + ext2fs_rb_set_black(parent); + ext2fs_rb_set_black(other->rb_left); + __rb_rotate_right(parent, root); + node = root->rb_node; + break; + } + } + } + if (node) + ext2fs_rb_set_black(node); +} + +void ext2fs_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 (ext2fs_rb_parent(old)) { + if (ext2fs_rb_parent(old)->rb_left == old) + ext2fs_rb_parent(old)->rb_left = node; + else + ext2fs_rb_parent(old)->rb_right = node; + } else + root->rb_node = node; + + child = node->rb_right; + parent = ext2fs_rb_parent(node); + color = ext2fs_rb_color(node); + + if (parent == old) { + parent = node; + } else { + if (child) + ext2fs_rb_set_parent(child, parent); + parent->rb_left = child; + + node->rb_right = old->rb_right; + ext2fs_rb_set_parent(old->rb_right, node); + } + + node->rb_parent_color = old->rb_parent_color; + node->rb_left = old->rb_left; + ext2fs_rb_set_parent(old->rb_left, node); + + goto color; + } + + parent = ext2fs_rb_parent(node); + color = ext2fs_rb_color(node); + + if (child) + ext2fs_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); +} + +/* + * This function returns the first node (in sort order) of the tree. + */ +struct rb_node *ext2fs_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 *ext2fs_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 *ext2fs_rb_next(struct rb_node *node) +{ + struct rb_node *parent; + + if (ext2fs_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 = ext2fs_rb_parent(node)) && node == parent->rb_right) + node = parent; + + return parent; +} + +struct rb_node *ext2fs_rb_prev(struct rb_node *node) +{ + struct rb_node *parent; + + if (ext2fs_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 = ext2fs_rb_parent(node)) && node == parent->rb_left) + node = parent; + + return parent; +} + +void ext2fs_rb_replace_node(struct rb_node *victim, struct rb_node *new, + struct rb_root *root) +{ + struct rb_node *parent = ext2fs_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) + ext2fs_rb_set_parent(victim->rb_left, new); + if (victim->rb_right) + ext2fs_rb_set_parent(victim->rb_right, new); + + /* Copy the pointers/colour from the victim to the replacement */ + *new = *victim; +} |