Add Red Black Tree support
authorKyungmin Park <kmpark@infradead.org>
Wed, 8 Oct 2008 02:01:17 +0000 (11:01 +0900)
committerWolfgang Denk <wd@denx.de>
Sat, 18 Oct 2008 19:54:01 +0000 (21:54 +0200)
Now it's used at UBI module. Of course other modules can use it.
If you want to use it, please define CONFIG_RBTREE

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
include/linux/rbtree.h [new file with mode: 0644]
lib_generic/Makefile
lib_generic/rbtree.c [new file with mode: 0644]

diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
new file mode 100644 (file)
index 0000000..6ff28e0
--- /dev/null
@@ -0,0 +1,160 @@
+/*
+  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
+  int two steps: as first thing the code must insert the element in
+  order as a red leaf in the tree, 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 <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 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))
+
+extern void rb_insert_color(struct rb_node *, struct rb_root *);
+extern void rb_erase(struct rb_node *, struct rb_root *);
+
+/* Find logical next and previous nodes in a tree */
+extern struct rb_node *rb_next(struct rb_node *);
+extern struct rb_node *rb_prev(struct rb_node *);
+extern struct rb_node *rb_first(struct rb_root *);
+extern struct rb_node *rb_last(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 */
index 7df5a2c3465bc5ded6696daf0114dc6b2e39fff8..d62c39bef76eedfa2d04e9f9b0e120e3de75e196 100644 (file)
@@ -45,6 +45,7 @@ COBJS-y += string.o
 COBJS-y        += strmhz.o
 COBJS-y += vsprintf.o
 COBJS-y += zlib.o
+COBJS-$(CONFIG_RBTREE) += rbtree.o
 
 COBJS  := $(COBJS-y)
 SRCS   := $(COBJS:.o=.c)
diff --git a/lib_generic/rbtree.c b/lib_generic/rbtree.c
new file mode 100644 (file)
index 0000000..42eab49
--- /dev/null
@@ -0,0 +1,390 @@
+/*
+  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 <ubi_uboot.h>
+#include <linux/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))
+                               {
+                                       struct rb_node *o_left;
+                                       if ((o_left = other->rb_left))
+                                               rb_set_black(o_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);
+                               if (other->rb_right)
+                                       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))
+                               {
+                                       register struct rb_node *o_right;
+                                       if ((o_right = other->rb_right))
+                                               rb_set_black(o_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);
+                               if (other->rb_left)
+                                       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;
+               child = node->rb_right;
+               parent = rb_parent(node);
+               color = rb_color(node);
+
+               if (child)
+                       rb_set_parent(child, parent);
+               if (parent == old) {
+                       parent->rb_right = child;
+                       parent = node;
+               } else
+                       parent->rb_left = child;
+
+               node->rb_parent_color = old->rb_parent_color;
+               node->rb_right = old->rb_right;
+               node->rb_left = old->rb_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;
+
+               rb_set_parent(old->rb_left, node);
+               if (old->rb_right)
+                       rb_set_parent(old->rb_right, 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);
+}
+
+/*
+ * This function returns the first node (in sort order) of the tree.
+ */
+struct rb_node *rb_first(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(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(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 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(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 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;
+}