summaryrefslogtreecommitdiffstats
path: root/lib/ext2fs/rbtree.h
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--lib/ext2fs/rbtree.h183
1 files changed, 183 insertions, 0 deletions
diff --git a/lib/ext2fs/rbtree.h b/lib/ext2fs/rbtree.h
new file mode 100644
index 0000000..790f5c1
--- /dev/null
+++ b/lib/ext2fs/rbtree.h
@@ -0,0 +1,183 @@
+/*
+ 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 dramatically 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 _LINUX_RBTREE_H
+#define _LINUX_RBTREE_H
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "compiler.h"
+
+#if __GNUC_PREREQ (4, 6)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-function"
+#endif
+
+struct rb_node
+{
+ uintptr_t 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 ext2fs_rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
+#define ext2fs_rb_color(r) ((r)->rb_parent_color & 1)
+#define ext2fs_rb_is_red(r) (!ext2fs_rb_color(r))
+#define ext2fs_rb_is_black(r) ext2fs_rb_color(r)
+#define ext2fs_rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0)
+#define ext2fs_rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0)
+
+static inline void ext2fs_rb_set_parent(struct rb_node *rb, struct rb_node *p)
+{
+ rb->rb_parent_color = (rb->rb_parent_color & 3) | (uintptr_t)p;
+}
+static inline void ext2fs_rb_set_color(struct rb_node *rb, int color)
+{
+ rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
+}
+
+#define RB_ROOT (struct rb_root) { NULL, }
+#define ext2fs_rb_entry(ptr, type, member) container_of(ptr, type, member)
+
+static inline int ext2fs_rb_empty_root(struct rb_root *root)
+{
+ return root->rb_node == NULL;
+}
+
+static inline int ext2fs_rb_empty_node(struct rb_node *node)
+{
+ return ext2fs_rb_parent(node) == node;
+}
+
+static inline void ext2fs_rb_clear_node(struct rb_node *node)
+{
+ ext2fs_rb_set_parent(node, node);
+}
+
+extern void ext2fs_rb_insert_color(struct rb_node *, struct rb_root *);
+extern void ext2fs_rb_erase(struct rb_node *, struct rb_root *);
+
+/* Find logical next and previous nodes in a tree */
+extern struct rb_node *ext2fs_rb_next(struct rb_node *);
+extern struct rb_node *ext2fs_rb_prev(struct rb_node *);
+extern struct rb_node *ext2fs_rb_first(const struct rb_root *);
+extern struct rb_node *ext2fs_rb_last(const struct rb_root *);
+
+/* Fast replacement of a single node without remove/rebalance/add/rebalance */
+extern void ext2fs_rb_replace_node(struct rb_node *victim, struct rb_node *new,
+ struct rb_root *root);
+
+static inline void ext2fs_rb_link_node(struct rb_node * node,
+ struct rb_node * parent,
+ struct rb_node ** rb_link)
+{
+ node->rb_parent_color = (uintptr_t)parent;
+ node->rb_left = node->rb_right = NULL;
+
+ *rb_link = node;
+}
+
+#if __GNUC_PREREQ (4, 6)
+#pragma GCC diagnostic pop
+#endif
+
+#endif /* _LINUX_RBTREE_H */