ebtree/eb32tree.h - haproxy - Gitiles

 /*
  * Elastic Binary Trees - macros and structures for operations on 32bit nodes.
  * Version 6.0.6
  * (C) 2002-2011 - Willy Tarreau <w@1wt.eu>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation, version 2.1
  * exclusively.
  *
  * This library 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 #ifndef _EB32TREE_H
 #define _EB32TREE_H

 #include "ebtree.h"


 /* Return the structure of type <type> whose member <member> points to <ptr> */
 #define eb32_entry(ptr, type, member) container_of(ptr, type, member)

 #define EB32_ROOT	EB_ROOT
 #define EB32_TREE_HEAD	EB_TREE_HEAD

 /* These types may sometimes already be defined */
 typedef unsigned int u32;
 typedef   signed int s32;

 /* This structure carries a node, a leaf, and a key. It must start with the
  * eb_node so that it can be cast into an eb_node. We could also have put some
  * sort of transparent union here to reduce the indirection level, but the fact
  * is, the end user is not meant to manipulate internals, so this is pointless.
  */
 struct eb32_node {
 	struct eb_node node; /* the tree node, must be at the beginning */
 	u32 key;
 };

 /*
  * Exported functions and macros.
  * Many of them are always inlined because they are extremely small, and
  * are generally called at most once or twice in a program.
  */

 /* Return leftmost node in the tree, or NULL if none */
 static inline struct eb32_node *eb32_first(struct eb_root *root)
 {
 	return eb32_entry(eb_first(root), struct eb32_node, node);
 }

 /* Return rightmost node in the tree, or NULL if none */
 static inline struct eb32_node *eb32_last(struct eb_root *root)
 {
 	return eb32_entry(eb_last(root), struct eb32_node, node);
 }

 /* Return next node in the tree, or NULL if none */
 static inline struct eb32_node *eb32_next(struct eb32_node *eb32)
 {
 	return eb32_entry(eb_next(&eb32->node), struct eb32_node, node);
 }

 /* Return previous node in the tree, or NULL if none */
 static inline struct eb32_node *eb32_prev(struct eb32_node *eb32)
 {
 	return eb32_entry(eb_prev(&eb32->node), struct eb32_node, node);
 }

 /* Return next leaf node within a duplicate sub-tree, or NULL if none. */
 static inline struct eb32_node *eb32_next_dup(struct eb32_node *eb32)
 {
 	return eb32_entry(eb_next_dup(&eb32->node), struct eb32_node, node);
 }

 /* Return previous leaf node within a duplicate sub-tree, or NULL if none. */
 static inline struct eb32_node *eb32_prev_dup(struct eb32_node *eb32)
 {
 	return eb32_entry(eb_prev_dup(&eb32->node), struct eb32_node, node);
 }

 /* Return next node in the tree, skipping duplicates, or NULL if none */
 static inline struct eb32_node *eb32_next_unique(struct eb32_node *eb32)
 {
 	return eb32_entry(eb_next_unique(&eb32->node), struct eb32_node, node);
 }

 /* Return previous node in the tree, skipping duplicates, or NULL if none */
 static inline struct eb32_node *eb32_prev_unique(struct eb32_node *eb32)
 {
 	return eb32_entry(eb_prev_unique(&eb32->node), struct eb32_node, node);
 }

 /* Delete node from the tree if it was linked in. Mark the node unused. Note
  * that this function relies on a non-inlined generic function: eb_delete.
  */
 static inline void eb32_delete(struct eb32_node *eb32)
 {
 	eb_delete(&eb32->node);
 }

 /*
  * The following functions are not inlined by default. They are declared
  * in eb32tree.c, which simply relies on their inline version.
  */
 REGPRM2 struct eb32_node *eb32_lookup(struct eb_root *root, u32 x);
 REGPRM2 struct eb32_node *eb32i_lookup(struct eb_root *root, s32 x);
 REGPRM2 struct eb32_node *eb32_lookup_le(struct eb_root *root, u32 x);
 REGPRM2 struct eb32_node *eb32_lookup_ge(struct eb_root *root, u32 x);
 REGPRM2 struct eb32_node *eb32_insert(struct eb_root *root, struct eb32_node *new);
 REGPRM2 struct eb32_node *eb32i_insert(struct eb_root *root, struct eb32_node *new);

 /*
  * The following functions are less likely to be used directly, because their
  * code is larger. The non-inlined version is preferred.
  */

 /* Delete node from the tree if it was linked in. Mark the node unused. */
 static forceinline void __eb32_delete(struct eb32_node *eb32)
 {
 	__eb_delete(&eb32->node);
 }

 /*
  * Find the first occurence of a key in the tree <root>. If none can be
  * found, return NULL.
  */
 static forceinline struct eb32_node *__eb32_lookup(struct eb_root *root, u32 x)
 {
 	struct eb32_node *node;
 	eb_troot_t *troot;
 	u32 y;
 	int node_bit;

 	troot = root->b[EB_LEFT];
 	if (unlikely(troot == NULL))
 		return NULL;

 	while (1) {
 		if ((eb_gettag(troot) == EB_LEAF)) {
 			node = container_of(eb_untag(troot, EB_LEAF),
 					    struct eb32_node, node.branches);
 			if (node->key == x)
 				return node;
 			else
 				return NULL;
 		}
 		node = container_of(eb_untag(troot, EB_NODE),
 				    struct eb32_node, node.branches);
 		node_bit = node->node.bit;

 		y = node->key ^ x;
 		if (!y) {
 			/* Either we found the node which holds the key, or
 			 * we have a dup tree. In the later case, we have to
 			 * walk it down left to get the first entry.
 			 */
 			if (node_bit < 0) {
 				troot = node->node.branches.b[EB_LEFT];
 				while (eb_gettag(troot) != EB_LEAF)
 					troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
 				node = container_of(eb_untag(troot, EB_LEAF),
 						    struct eb32_node, node.branches);
 			}
 			return node;
 		}

 		if ((y >> node_bit) >= EB_NODE_BRANCHES)
 			return NULL; /* no more common bits */

 		troot = node->node.branches.b[(x >> node_bit) & EB_NODE_BRANCH_MASK];
 	}
 }

 /*
  * Find the first occurence of a signed key in the tree <root>. If none can
  * be found, return NULL.
  */
 static forceinline struct eb32_node *__eb32i_lookup(struct eb_root *root, s32 x)
 {
 	struct eb32_node *node;
 	eb_troot_t *troot;
 	u32 key = x ^ 0x80000000;
 	u32 y;
 	int node_bit;

 	troot = root->b[EB_LEFT];
 	if (unlikely(troot == NULL))
 		return NULL;

 	while (1) {
 		if ((eb_gettag(troot) == EB_LEAF)) {
 			node = container_of(eb_untag(troot, EB_LEAF),
 					    struct eb32_node, node.branches);
 			if (node->key == (u32)x)
 				return node;
 			else
 				return NULL;
 		}
 		node = container_of(eb_untag(troot, EB_NODE),
 				    struct eb32_node, node.branches);
 		node_bit = node->node.bit;

 		y = node->key ^ x;
 		if (!y) {
 			/* Either we found the node which holds the key, or
 			 * we have a dup tree. In the later case, we have to
 			 * walk it down left to get the first entry.
 			 */
 			if (node_bit < 0) {
 				troot = node->node.branches.b[EB_LEFT];
 				while (eb_gettag(troot) != EB_LEAF)
 					troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
 				node = container_of(eb_untag(troot, EB_LEAF),
 						    struct eb32_node, node.branches);
 			}
 			return node;
 		}

 		if ((y >> node_bit) >= EB_NODE_BRANCHES)
 			return NULL; /* no more common bits */

 		troot = node->node.branches.b[(key >> node_bit) & EB_NODE_BRANCH_MASK];
 	}
 }

 /* Insert eb32_node <new> into subtree starting at node root <root>.
  * Only new->key needs be set with the key. The eb32_node is returned.
  * If root->b[EB_RGHT]==1, the tree may only contain unique keys.
  */
 static forceinline struct eb32_node *
 __eb32_insert(struct eb_root *root, struct eb32_node *new) {
 	struct eb32_node *old;
 	unsigned int side;
 	eb_troot_t *troot, **up_ptr;
 	u32 newkey; /* caching the key saves approximately one cycle */
 	eb_troot_t *root_right;
 	eb_troot_t *new_left, *new_rght;
 	eb_troot_t *new_leaf;
 	int old_node_bit;

 	side = EB_LEFT;
 	troot = root->b[EB_LEFT];
 	root_right = root->b[EB_RGHT];
 	if (unlikely(troot == NULL)) {
 		/* Tree is empty, insert the leaf part below the left branch */
 		root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
 		new->node.leaf_p = eb_dotag(root, EB_LEFT);
 		new->node.node_p = NULL; /* node part unused */
 		return new;
 	}

 	/* The tree descent is fairly easy :
 	 *  - first, check if we have reached a leaf node
 	 *  - second, check if we have gone too far
 	 *  - third, reiterate
 	 * Everywhere, we use <new> for the node node we are inserting, <root>
 	 * for the node we attach it to, and <old> for the node we are
 	 * displacing below <new>. <troot> will always point to the future node
 	 * (tagged with its type). <side> carries the side the node <new> is
 	 * attached to below its parent, which is also where previous node
 	 * was attached. <newkey> carries the key being inserted.
 	 */
 	newkey = new->key;

 	while (1) {
 		if (eb_gettag(troot) == EB_LEAF) {
 			/* insert above a leaf */
 			old = container_of(eb_untag(troot, EB_LEAF),
 					    struct eb32_node, node.branches);
 			new->node.node_p = old->node.leaf_p;
 			up_ptr = &old->node.leaf_p;
 			break;
 		}

 		/* OK we're walking down this link */
 		old = container_of(eb_untag(troot, EB_NODE),
 				    struct eb32_node, node.branches);
 		old_node_bit = old->node.bit;

 		/* Stop going down when we don't have common bits anymore. We
 		 * also stop in front of a duplicates tree because it means we
 		 * have to insert above.
 		 */

 		if ((old_node_bit < 0) || /* we're above a duplicate tree, stop here */
 		    (((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
 			/* The tree did not contain the key, so we insert <new> before the node
 			 * <old>, and set ->bit to designate the lowest bit position in <new>
 			 * which applies to ->branches.b[].
 			 */
 			new->node.node_p = old->node.node_p;
 			up_ptr = &old->node.node_p;
 			break;
 		}

 		/* walk down */
 		root = &old->node.branches;
 		side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
 		troot = root->b[side];
 	}

 	new_left = eb_dotag(&new->node.branches, EB_LEFT);
 	new_rght = eb_dotag(&new->node.branches, EB_RGHT);
 	new_leaf = eb_dotag(&new->node.branches, EB_LEAF);

 	/* We need the common higher bits between new->key and old->key.
 	 * What differences are there between new->key and the node here ?
 	 * NOTE that bit(new) is always < bit(root) because highest
 	 * bit of new->key and old->key are identical here (otherwise they
 	 * would sit on different branches).
 	 */

 	// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
 	new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;

 	if (new->key == old->key) {
 		new->node.bit = -1; /* mark as new dup tree, just in case */

 		if (likely(eb_gettag(root_right))) {
 			/* we refuse to duplicate this key if the tree is
 			 * tagged as containing only unique keys.
 			 */
 			return old;
 		}

 		if (eb_gettag(troot) != EB_LEAF) {
 			/* there was already a dup tree below */
 			struct eb_node *ret;
 			ret = eb_insert_dup(&old->node, &new->node);
 			return container_of(ret, struct eb32_node, node);
 		}
 		/* otherwise fall through */
 	}

 	if (new->key >= old->key) {
 		new->node.branches.b[EB_LEFT] = troot;
 		new->node.branches.b[EB_RGHT] = new_leaf;
 		new->node.leaf_p = new_rght;
 		*up_ptr = new_left;
 	}
 	else {
 		new->node.branches.b[EB_LEFT] = new_leaf;
 		new->node.branches.b[EB_RGHT] = troot;
 		new->node.leaf_p = new_left;
 		*up_ptr = new_rght;
 	}

 	/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
 	 * parent is already set to <new>, and the <root>'s branch is still in
 	 * <side>. Update the root's leaf till we have it. Note that we can also
 	 * find the side by checking the side of new->node.node_p.
 	 */

 	root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
 	return new;
 }

 /* Insert eb32_node <new> into subtree starting at node root <root>, using
  * signed keys. Only new->key needs be set with the key. The eb32_node
  * is returned. If root->b[EB_RGHT]==1, the tree may only contain unique keys.
  */
 static forceinline struct eb32_node *
 __eb32i_insert(struct eb_root *root, struct eb32_node *new) {
 	struct eb32_node *old;
 	unsigned int side;
 	eb_troot_t *troot, **up_ptr;
 	int newkey; /* caching the key saves approximately one cycle */
 	eb_troot_t *root_right;
 	eb_troot_t *new_left, *new_rght;
 	eb_troot_t *new_leaf;
 	int old_node_bit;

 	side = EB_LEFT;
 	troot = root->b[EB_LEFT];
 	root_right = root->b[EB_RGHT];
 	if (unlikely(troot == NULL)) {
 		/* Tree is empty, insert the leaf part below the left branch */
 		root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
 		new->node.leaf_p = eb_dotag(root, EB_LEFT);
 		new->node.node_p = NULL; /* node part unused */
 		return new;
 	}

 	/* The tree descent is fairly easy :
 	 *  - first, check if we have reached a leaf node
 	 *  - second, check if we have gone too far
 	 *  - third, reiterate
 	 * Everywhere, we use <new> for the node node we are inserting, <root>
 	 * for the node we attach it to, and <old> for the node we are
 	 * displacing below <new>. <troot> will always point to the future node
 	 * (tagged with its type). <side> carries the side the node <new> is
 	 * attached to below its parent, which is also where previous node
 	 * was attached. <newkey> carries a high bit shift of the key being
 	 * inserted in order to have negative keys stored before positive
 	 * ones.
 	 */
 	newkey = new->key + 0x80000000;

 	while (1) {
 		if (eb_gettag(troot) == EB_LEAF) {
 			old = container_of(eb_untag(troot, EB_LEAF),
 					    struct eb32_node, node.branches);
 			new->node.node_p = old->node.leaf_p;
 			up_ptr = &old->node.leaf_p;
 			break;
 		}

 		/* OK we're walking down this link */
 		old = container_of(eb_untag(troot, EB_NODE),
 				    struct eb32_node, node.branches);
 		old_node_bit = old->node.bit;

 		/* Stop going down when we don't have common bits anymore. We
 		 * also stop in front of a duplicates tree because it means we
 		 * have to insert above.
 		 */

 		if ((old_node_bit < 0) || /* we're above a duplicate tree, stop here */
 		    (((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
 			/* The tree did not contain the key, so we insert <new> before the node
 			 * <old>, and set ->bit to designate the lowest bit position in <new>
 			 * which applies to ->branches.b[].
 			 */
 			new->node.node_p = old->node.node_p;
 			up_ptr = &old->node.node_p;
 			break;
 		}

 		/* walk down */
 		root = &old->node.branches;
 		side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
 		troot = root->b[side];
 	}

 	new_left = eb_dotag(&new->node.branches, EB_LEFT);
 	new_rght = eb_dotag(&new->node.branches, EB_RGHT);
 	new_leaf = eb_dotag(&new->node.branches, EB_LEAF);

 	/* We need the common higher bits between new->key and old->key.
 	 * What differences are there between new->key and the node here ?
 	 * NOTE that bit(new) is always < bit(root) because highest
 	 * bit of new->key and old->key are identical here (otherwise they
 	 * would sit on different branches).
 	 */

 	// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
 	new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;

 	if (new->key == old->key) {
 		new->node.bit = -1; /* mark as new dup tree, just in case */

 		if (likely(eb_gettag(root_right))) {
 			/* we refuse to duplicate this key if the tree is
 			 * tagged as containing only unique keys.
 			 */
 			return old;
 		}

 		if (eb_gettag(troot) != EB_LEAF) {
 			/* there was already a dup tree below */
 			struct eb_node *ret;
 			ret = eb_insert_dup(&old->node, &new->node);
 			return container_of(ret, struct eb32_node, node);
 		}
 		/* otherwise fall through */
 	}

 	if ((s32)new->key >= (s32)old->key) {
 		new->node.branches.b[EB_LEFT] = troot;
 		new->node.branches.b[EB_RGHT] = new_leaf;
 		new->node.leaf_p = new_rght;
 		*up_ptr = new_left;
 	}
 	else {
 		new->node.branches.b[EB_LEFT] = new_leaf;
 		new->node.branches.b[EB_RGHT] = troot;
 		new->node.leaf_p = new_left;
 		*up_ptr = new_rght;
 	}

 	/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
 	 * parent is already set to <new>, and the <root>'s branch is still in
 	 * <side>. Update the root's leaf till we have it. Note that we can also
 	 * find the side by checking the side of new->node.node_p.
 	 */

 	root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
 	return new;
 }

 #endif /* _EB32_TREE_H */
	/*
	* Elastic Binary Trees - macros and structures for operations on 32bit nodes.
	* Version 6.0.6
	* (C) 2002-2011 - Willy Tarreau <w@1wt.eu>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation, version 2.1
	* exclusively.
	*
	* This library 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
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#ifndef _EB32TREE_H
	#define _EB32TREE_H

	#include "ebtree.h"


	/* Return the structure of type <type> whose member <member> points to <ptr> */
	#define eb32_entry(ptr, type, member) container_of(ptr, type, member)

	#define EB32_ROOT EB_ROOT
	#define EB32_TREE_HEAD EB_TREE_HEAD

	/* These types may sometimes already be defined */
	typedef unsigned int u32;
	typedef signed int s32;

	/* This structure carries a node, a leaf, and a key. It must start with the
	* eb_node so that it can be cast into an eb_node. We could also have put some
	* sort of transparent union here to reduce the indirection level, but the fact
	* is, the end user is not meant to manipulate internals, so this is pointless.
	*/
	struct eb32_node {
	struct eb_node node; /* the tree node, must be at the beginning */
	u32 key;
	};

	/*
	* Exported functions and macros.
	* Many of them are always inlined because they are extremely small, and
	* are generally called at most once or twice in a program.
	*/

	/* Return leftmost node in the tree, or NULL if none */
	static inline struct eb32_node eb32_first(struct eb_root root)
	{
	return eb32_entry(eb_first(root), struct eb32_node, node);
	}

	/* Return rightmost node in the tree, or NULL if none */
	static inline struct eb32_node eb32_last(struct eb_root root)
	{
	return eb32_entry(eb_last(root), struct eb32_node, node);
	}

	/* Return next node in the tree, or NULL if none */
	static inline struct eb32_node eb32_next(struct eb32_node eb32)
	{
	return eb32_entry(eb_next(&eb32->node), struct eb32_node, node);
	}

	/* Return previous node in the tree, or NULL if none */
	static inline struct eb32_node eb32_prev(struct eb32_node eb32)
	{
	return eb32_entry(eb_prev(&eb32->node), struct eb32_node, node);
	}

	/* Return next leaf node within a duplicate sub-tree, or NULL if none. */
	static inline struct eb32_node eb32_next_dup(struct eb32_node eb32)
	{
	return eb32_entry(eb_next_dup(&eb32->node), struct eb32_node, node);
	}

	/* Return previous leaf node within a duplicate sub-tree, or NULL if none. */
	static inline struct eb32_node eb32_prev_dup(struct eb32_node eb32)
	{
	return eb32_entry(eb_prev_dup(&eb32->node), struct eb32_node, node);
	}

	/* Return next node in the tree, skipping duplicates, or NULL if none */
	static inline struct eb32_node eb32_next_unique(struct eb32_node eb32)
	{
	return eb32_entry(eb_next_unique(&eb32->node), struct eb32_node, node);
	}

	/* Return previous node in the tree, skipping duplicates, or NULL if none */
	static inline struct eb32_node eb32_prev_unique(struct eb32_node eb32)
	{
	return eb32_entry(eb_prev_unique(&eb32->node), struct eb32_node, node);
	}

	/* Delete node from the tree if it was linked in. Mark the node unused. Note
	* that this function relies on a non-inlined generic function: eb_delete.
	*/
	static inline void eb32_delete(struct eb32_node *eb32)
	{
	eb_delete(&eb32->node);
	}

	/*
	* The following functions are not inlined by default. They are declared
	* in eb32tree.c, which simply relies on their inline version.
	*/
	REGPRM2 struct eb32_node eb32_lookup(struct eb_root root, u32 x);
	REGPRM2 struct eb32_node eb32i_lookup(struct eb_root root, s32 x);
	REGPRM2 struct eb32_node eb32_lookup_le(struct eb_root root, u32 x);
	REGPRM2 struct eb32_node eb32_lookup_ge(struct eb_root root, u32 x);
	REGPRM2 struct eb32_node eb32_insert(struct eb_root root, struct eb32_node *new);
	REGPRM2 struct eb32_node eb32i_insert(struct eb_root root, struct eb32_node *new);

	/*
	* The following functions are less likely to be used directly, because their
	* code is larger. The non-inlined version is preferred.
	*/

	/* Delete node from the tree if it was linked in. Mark the node unused. */
	static forceinline void __eb32_delete(struct eb32_node *eb32)
	{
	__eb_delete(&eb32->node);
	}

	/*
	* Find the first occurence of a key in the tree <root>. If none can be
	* found, return NULL.
	*/
	static forceinline struct eb32_node __eb32_lookup(struct eb_root root, u32 x)
	{
	struct eb32_node *node;
	eb_troot_t *troot;
	u32 y;
	int node_bit;

	troot = root->b[EB_LEFT];
	if (unlikely(troot == NULL))
	return NULL;

	while (1) {
	if ((eb_gettag(troot) == EB_LEAF)) {
	node = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	if (node->key == x)
	return node;
	else
	return NULL;
	}
	node = container_of(eb_untag(troot, EB_NODE),
	struct eb32_node, node.branches);
	node_bit = node->node.bit;

	y = node->key ^ x;
	if (!y) {
	/* Either we found the node which holds the key, or
	* we have a dup tree. In the later case, we have to
	* walk it down left to get the first entry.
	*/
	if (node_bit < 0) {
	troot = node->node.branches.b[EB_LEFT];
	while (eb_gettag(troot) != EB_LEAF)
	troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
	node = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	}
	return node;
	}

	if ((y >> node_bit) >= EB_NODE_BRANCHES)
	return NULL; /* no more common bits */

	troot = node->node.branches.b[(x >> node_bit) & EB_NODE_BRANCH_MASK];
	}
	}

	/*
	* Find the first occurence of a signed key in the tree <root>. If none can
	* be found, return NULL.
	*/
	static forceinline struct eb32_node __eb32i_lookup(struct eb_root root, s32 x)
	{
	struct eb32_node *node;
	eb_troot_t *troot;
	u32 key = x ^ 0x80000000;
	u32 y;
	int node_bit;

	troot = root->b[EB_LEFT];
	if (unlikely(troot == NULL))
	return NULL;

	while (1) {
	if ((eb_gettag(troot) == EB_LEAF)) {
	node = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	if (node->key == (u32)x)
	return node;
	else
	return NULL;
	}
	node = container_of(eb_untag(troot, EB_NODE),
	struct eb32_node, node.branches);
	node_bit = node->node.bit;

	y = node->key ^ x;
	if (!y) {
	/* Either we found the node which holds the key, or
	* we have a dup tree. In the later case, we have to
	* walk it down left to get the first entry.
	*/
	if (node_bit < 0) {
	troot = node->node.branches.b[EB_LEFT];
	while (eb_gettag(troot) != EB_LEAF)
	troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
	node = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	}
	return node;
	}

	if ((y >> node_bit) >= EB_NODE_BRANCHES)
	return NULL; /* no more common bits */

	troot = node->node.branches.b[(key >> node_bit) & EB_NODE_BRANCH_MASK];
	}
	}

	/* Insert eb32_node <new> into subtree starting at node root <root>.
	* Only new->key needs be set with the key. The eb32_node is returned.
	* If root->b[EB_RGHT]==1, the tree may only contain unique keys.
	*/
	static forceinline struct eb32_node *
	__eb32_insert(struct eb_root root, struct eb32_node new) {
	struct eb32_node *old;
	unsigned int side;
	eb_troot_t troot, *up_ptr;
	u32 newkey; /* caching the key saves approximately one cycle */
	eb_troot_t *root_right;
	eb_troot_t new_left, new_rght;
	eb_troot_t *new_leaf;
	int old_node_bit;

	side = EB_LEFT;
	troot = root->b[EB_LEFT];
	root_right = root->b[EB_RGHT];
	if (unlikely(troot == NULL)) {
	/* Tree is empty, insert the leaf part below the left branch */
	root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
	new->node.leaf_p = eb_dotag(root, EB_LEFT);
	new->node.node_p = NULL; /* node part unused */
	return new;
	}

	/* The tree descent is fairly easy :
	* - first, check if we have reached a leaf node
	* - second, check if we have gone too far
	* - third, reiterate
	* Everywhere, we use <new> for the node node we are inserting, <root>
	* for the node we attach it to, and <old> for the node we are
	* displacing below <new>. <troot> will always point to the future node
	* (tagged with its type). <side> carries the side the node <new> is
	* attached to below its parent, which is also where previous node
	* was attached. <newkey> carries the key being inserted.
	*/
	newkey = new->key;

	while (1) {
	if (eb_gettag(troot) == EB_LEAF) {
	/* insert above a leaf */
	old = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	new->node.node_p = old->node.leaf_p;
	up_ptr = &old->node.leaf_p;
	break;
	}

	/* OK we're walking down this link */
	old = container_of(eb_untag(troot, EB_NODE),
	struct eb32_node, node.branches);
	old_node_bit = old->node.bit;

	/* Stop going down when we don't have common bits anymore. We
	* also stop in front of a duplicates tree because it means we
	* have to insert above.
	*/

	if ((old_node_bit < 0) \|\| /* we're above a duplicate tree, stop here */
	(((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
	/* The tree did not contain the key, so we insert <new> before the node
	* <old>, and set ->bit to designate the lowest bit position in <new>
	* which applies to ->branches.b[].
	*/
	new->node.node_p = old->node.node_p;
	up_ptr = &old->node.node_p;
	break;
	}

	/* walk down */
	root = &old->node.branches;
	side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
	troot = root->b[side];
	}

	new_left = eb_dotag(&new->node.branches, EB_LEFT);
	new_rght = eb_dotag(&new->node.branches, EB_RGHT);
	new_leaf = eb_dotag(&new->node.branches, EB_LEAF);

	/* We need the common higher bits between new->key and old->key.
	* What differences are there between new->key and the node here ?
	* NOTE that bit(new) is always < bit(root) because highest
	* bit of new->key and old->key are identical here (otherwise they
	* would sit on different branches).
	*/

	// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
	new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;

	if (new->key == old->key) {
	new->node.bit = -1; /* mark as new dup tree, just in case */

	if (likely(eb_gettag(root_right))) {
	/* we refuse to duplicate this key if the tree is
	* tagged as containing only unique keys.
	*/
	return old;
	}

	if (eb_gettag(troot) != EB_LEAF) {
	/* there was already a dup tree below */
	struct eb_node *ret;
	ret = eb_insert_dup(&old->node, &new->node);
	return container_of(ret, struct eb32_node, node);
	}
	/* otherwise fall through */
	}

	if (new->key >= old->key) {
	new->node.branches.b[EB_LEFT] = troot;
	new->node.branches.b[EB_RGHT] = new_leaf;
	new->node.leaf_p = new_rght;
	*up_ptr = new_left;
	}
	else {
	new->node.branches.b[EB_LEFT] = new_leaf;
	new->node.branches.b[EB_RGHT] = troot;
	new->node.leaf_p = new_left;
	*up_ptr = new_rght;
	}

	/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
	* parent is already set to <new>, and the <root>'s branch is still in
	* <side>. Update the root's leaf till we have it. Note that we can also
	* find the side by checking the side of new->node.node_p.
	*/

	root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
	return new;
	}

	/* Insert eb32_node <new> into subtree starting at node root <root>, using
	* signed keys. Only new->key needs be set with the key. The eb32_node
	* is returned. If root->b[EB_RGHT]==1, the tree may only contain unique keys.
	*/
	static forceinline struct eb32_node *
	__eb32i_insert(struct eb_root root, struct eb32_node new) {
	struct eb32_node *old;
	unsigned int side;
	eb_troot_t troot, *up_ptr;
	int newkey; /* caching the key saves approximately one cycle */
	eb_troot_t *root_right;
	eb_troot_t new_left, new_rght;
	eb_troot_t *new_leaf;
	int old_node_bit;

	side = EB_LEFT;
	troot = root->b[EB_LEFT];
	root_right = root->b[EB_RGHT];
	if (unlikely(troot == NULL)) {
	/* Tree is empty, insert the leaf part below the left branch */
	root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
	new->node.leaf_p = eb_dotag(root, EB_LEFT);
	new->node.node_p = NULL; /* node part unused */
	return new;
	}

	/* The tree descent is fairly easy :
	* - first, check if we have reached a leaf node
	* - second, check if we have gone too far
	* - third, reiterate
	* Everywhere, we use <new> for the node node we are inserting, <root>
	* for the node we attach it to, and <old> for the node we are
	* displacing below <new>. <troot> will always point to the future node
	* (tagged with its type). <side> carries the side the node <new> is
	* attached to below its parent, which is also where previous node
	* was attached. <newkey> carries a high bit shift of the key being
	* inserted in order to have negative keys stored before positive
	* ones.
	*/
	newkey = new->key + 0x80000000;

	while (1) {
	if (eb_gettag(troot) == EB_LEAF) {
	old = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	new->node.node_p = old->node.leaf_p;
	up_ptr = &old->node.leaf_p;
	break;
	}

	/* OK we're walking down this link */
	old = container_of(eb_untag(troot, EB_NODE),
	struct eb32_node, node.branches);
	old_node_bit = old->node.bit;

	/* Stop going down when we don't have common bits anymore. We
	* also stop in front of a duplicates tree because it means we
	* have to insert above.
	*/

	if ((old_node_bit < 0) \|\| /* we're above a duplicate tree, stop here */
	(((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
	/* The tree did not contain the key, so we insert <new> before the node
	* <old>, and set ->bit to designate the lowest bit position in <new>
	* which applies to ->branches.b[].
	*/
	new->node.node_p = old->node.node_p;
	up_ptr = &old->node.node_p;
	break;
	}

	/* walk down */
	root = &old->node.branches;
	side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
	troot = root->b[side];
	}

	new_left = eb_dotag(&new->node.branches, EB_LEFT);
	new_rght = eb_dotag(&new->node.branches, EB_RGHT);
	new_leaf = eb_dotag(&new->node.branches, EB_LEAF);

	/* We need the common higher bits between new->key and old->key.
	* What differences are there between new->key and the node here ?
	* NOTE that bit(new) is always < bit(root) because highest
	* bit of new->key and old->key are identical here (otherwise they
	* would sit on different branches).
	*/

	// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
	new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;

	if (new->key == old->key) {
	new->node.bit = -1; /* mark as new dup tree, just in case */

	if (likely(eb_gettag(root_right))) {
	/* we refuse to duplicate this key if the tree is
	* tagged as containing only unique keys.
	*/
	return old;
	}

	if (eb_gettag(troot) != EB_LEAF) {
	/* there was already a dup tree below */
	struct eb_node *ret;
	ret = eb_insert_dup(&old->node, &new->node);
	return container_of(ret, struct eb32_node, node);
	}
	/* otherwise fall through */
	}

	if ((s32)new->key >= (s32)old->key) {
	new->node.branches.b[EB_LEFT] = troot;
	new->node.branches.b[EB_RGHT] = new_leaf;
	new->node.leaf_p = new_rght;
	*up_ptr = new_left;
	}
	else {
	new->node.branches.b[EB_LEFT] = new_leaf;
	new->node.branches.b[EB_RGHT] = troot;
	new->node.leaf_p = new_left;
	*up_ptr = new_rght;
	}

	/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
	* parent is already set to <new>, and the <root>'s branch is still in
	* <side>. Update the root's leaf till we have it. Note that we can also
	* find the side by checking the side of new->node.node_p.
	*/

	root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
	return new;
	}

	#endif /* _EB32_TREE_H */