ebtree/eb32tree.c - haproxy - Gitiles

 /*
  * Elastic Binary Trees - exported functions 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
  */

 /* Consult eb32tree.h for more details about those functions */

 #include "eb32tree.h"

 REGPRM2 struct eb32_node *eb32_insert(struct eb_root *root, struct eb32_node *new)
 {
 	return __eb32_insert(root, new);
 }

 REGPRM2 struct eb32_node *eb32i_insert(struct eb_root *root, struct eb32_node *new)
 {
 	return __eb32i_insert(root, new);
 }

 REGPRM2 struct eb32_node *eb32_lookup(struct eb_root *root, u32 x)
 {
 	return __eb32_lookup(root, x);
 }

 REGPRM2 struct eb32_node *eb32i_lookup(struct eb_root *root, s32 x)
 {
 	return __eb32i_lookup(root, x);
 }

 /*
  * Find the last occurrence of the highest key in the tree <root>, which is
  * equal to or less than <x>. NULL is returned is no key matches.
  */
 REGPRM2 struct eb32_node *eb32_lookup_le(struct eb_root *root, u32 x)
 {
 	struct eb32_node *node;
 	eb_troot_t *troot;

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

 	while (1) {
 		if ((eb_gettag(troot) == EB_LEAF)) {
 			/* We reached a leaf, which means that the whole upper
 			 * parts were common. We will return either the current
 			 * node or its next one if the former is too small.
 			 */
 			node = container_of(eb_untag(troot, EB_LEAF),
 					    struct eb32_node, node.branches);
 			if (node->key <= x)
 				return node;
 			/* return prev */
 			troot = node->node.leaf_p;
 			break;
 		}
 		node = container_of(eb_untag(troot, EB_NODE),
 				    struct eb32_node, node.branches);

 		if (node->node.bit < 0) {
 			/* We're at the top of a dup tree. Either we got a
 			 * matching value and we return the rightmost node, or
 			 * we don't and we skip the whole subtree to return the
 			 * prev node before the subtree. Note that since we're
 			 * at the top of the dup tree, we can simply return the
 			 * prev node without first trying to escape from the
 			 * tree.
 			 */
 			if (node->key <= x) {
 				troot = node->node.branches.b[EB_RGHT];
 				while (eb_gettag(troot) != EB_LEAF)
 					troot = (eb_untag(troot, EB_NODE))->b[EB_RGHT];
 				return container_of(eb_untag(troot, EB_LEAF),
 						    struct eb32_node, node.branches);
 			}
 			/* return prev */
 			troot = node->node.node_p;
 			break;
 		}

 		if (((x ^ node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
 			/* No more common bits at all. Either this node is too
 			 * small and we need to get its highest value, or it is
 			 * too large, and we need to get the prev value.
 			 */
 			if ((node->key >> node->node.bit) < (x >> node->node.bit)) {
 				troot = node->node.branches.b[EB_RGHT];
 				return eb32_entry(eb_walk_down(troot, EB_RGHT), struct eb32_node, node);
 			}

 			/* Further values will be too high here, so return the prev
 			 * unique node (if it exists).
 			 */
 			troot = node->node.node_p;
 			break;
 		}
 		troot = node->node.branches.b[(x >> node->node.bit) & EB_NODE_BRANCH_MASK];
 	}

 	/* If we get here, it means we want to report previous node before the
 	 * current one which is not above. <troot> is already initialised to
 	 * the parent's branches.
 	 */
 	while (eb_gettag(troot) == EB_LEFT) {
 		/* Walking up from left branch. We must ensure that we never
 		 * walk beyond root.
 		 */
 		if (unlikely(eb_clrtag((eb_untag(troot, EB_LEFT))->b[EB_RGHT]) == NULL))
 			return NULL;
 		troot = (eb_root_to_node(eb_untag(troot, EB_LEFT)))->node_p;
 	}
 	/* Note that <troot> cannot be NULL at this stage */
 	troot = (eb_untag(troot, EB_RGHT))->b[EB_LEFT];
 	node = eb32_entry(eb_walk_down(troot, EB_RGHT), struct eb32_node, node);
 	return node;
 }

 /*
  * Find the first occurrence of the lowest key in the tree <root>, which is
  * equal to or greater than <x>. NULL is returned is no key matches.
  */
 REGPRM2 struct eb32_node *eb32_lookup_ge(struct eb_root *root, u32 x)
 {
 	struct eb32_node *node;
 	eb_troot_t *troot;

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

 	while (1) {
 		if ((eb_gettag(troot) == EB_LEAF)) {
 			/* We reached a leaf, which means that the whole upper
 			 * parts were common. We will return either the current
 			 * node or its next one if the former is too small.
 			 */
 			node = container_of(eb_untag(troot, EB_LEAF),
 					    struct eb32_node, node.branches);
 			if (node->key >= x)
 				return node;
 			/* return next */
 			troot = node->node.leaf_p;
 			break;
 		}
 		node = container_of(eb_untag(troot, EB_NODE),
 				    struct eb32_node, node.branches);

 		if (node->node.bit < 0) {
 			/* We're at the top of a dup tree. Either we got a
 			 * matching value and we return the leftmost node, or
 			 * we don't and we skip the whole subtree to return the
 			 * next node after the subtree. Note that since we're
 			 * at the top of the dup tree, we can simply return the
 			 * next node without first trying to escape from the
 			 * tree.
 			 */
 			if (node->key >= x) {
 				troot = node->node.branches.b[EB_LEFT];
 				while (eb_gettag(troot) != EB_LEAF)
 					troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
 				return container_of(eb_untag(troot, EB_LEAF),
 						    struct eb32_node, node.branches);
 			}
 			/* return next */
 			troot = node->node.node_p;
 			break;
 		}

 		if (((x ^ node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
 			/* No more common bits at all. Either this node is too
 			 * large and we need to get its lowest value, or it is too
 			 * small, and we need to get the next value.
 			 */
 			if ((node->key >> node->node.bit) > (x >> node->node.bit)) {
 				troot = node->node.branches.b[EB_LEFT];
 				return eb32_entry(eb_walk_down(troot, EB_LEFT), struct eb32_node, node);
 			}

 			/* Further values will be too low here, so return the next
 			 * unique node (if it exists).
 			 */
 			troot = node->node.node_p;
 			break;
 		}
 		troot = node->node.branches.b[(x >> node->node.bit) & EB_NODE_BRANCH_MASK];
 	}

 	/* If we get here, it means we want to report next node after the
 	 * current one which is not below. <troot> is already initialised
 	 * to the parent's branches.
 	 */
 	while (eb_gettag(troot) != EB_LEFT)
 		/* Walking up from right branch, so we cannot be below root */
 		troot = (eb_root_to_node(eb_untag(troot, EB_RGHT)))->node_p;

 	/* Note that <troot> cannot be NULL at this stage */
 	troot = (eb_untag(troot, EB_LEFT))->b[EB_RGHT];
 	if (eb_clrtag(troot) == NULL)
 		return NULL;

 	node = eb32_entry(eb_walk_down(troot, EB_LEFT), struct eb32_node, node);
 	return node;
 }
	/*
	* Elastic Binary Trees - exported functions 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
	*/

	/* Consult eb32tree.h for more details about those functions */

	#include "eb32tree.h"

	REGPRM2 struct eb32_node eb32_insert(struct eb_root root, struct eb32_node *new)
	{
	return __eb32_insert(root, new);
	}

	REGPRM2 struct eb32_node eb32i_insert(struct eb_root root, struct eb32_node *new)
	{
	return __eb32i_insert(root, new);
	}

	REGPRM2 struct eb32_node eb32_lookup(struct eb_root root, u32 x)
	{
	return __eb32_lookup(root, x);
	}

	REGPRM2 struct eb32_node eb32i_lookup(struct eb_root root, s32 x)
	{
	return __eb32i_lookup(root, x);
	}

	/*
	* Find the last occurrence of the highest key in the tree <root>, which is
	* equal to or less than <x>. NULL is returned is no key matches.
	*/
	REGPRM2 struct eb32_node eb32_lookup_le(struct eb_root root, u32 x)
	{
	struct eb32_node *node;
	eb_troot_t *troot;

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

	while (1) {
	if ((eb_gettag(troot) == EB_LEAF)) {
	/* We reached a leaf, which means that the whole upper
	* parts were common. We will return either the current
	* node or its next one if the former is too small.
	*/
	node = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	if (node->key <= x)
	return node;
	/* return prev */
	troot = node->node.leaf_p;
	break;
	}
	node = container_of(eb_untag(troot, EB_NODE),
	struct eb32_node, node.branches);

	if (node->node.bit < 0) {
	/* We're at the top of a dup tree. Either we got a
	* matching value and we return the rightmost node, or
	* we don't and we skip the whole subtree to return the
	* prev node before the subtree. Note that since we're
	* at the top of the dup tree, we can simply return the
	* prev node without first trying to escape from the
	* tree.
	*/
	if (node->key <= x) {
	troot = node->node.branches.b[EB_RGHT];
	while (eb_gettag(troot) != EB_LEAF)
	troot = (eb_untag(troot, EB_NODE))->b[EB_RGHT];
	return container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	}
	/* return prev */
	troot = node->node.node_p;
	break;
	}

	if (((x ^ node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
	/* No more common bits at all. Either this node is too
	* small and we need to get its highest value, or it is
	* too large, and we need to get the prev value.
	*/
	if ((node->key >> node->node.bit) < (x >> node->node.bit)) {
	troot = node->node.branches.b[EB_RGHT];
	return eb32_entry(eb_walk_down(troot, EB_RGHT), struct eb32_node, node);
	}

	/* Further values will be too high here, so return the prev
	* unique node (if it exists).
	*/
	troot = node->node.node_p;
	break;
	}
	troot = node->node.branches.b[(x >> node->node.bit) & EB_NODE_BRANCH_MASK];
	}

	/* If we get here, it means we want to report previous node before the
	* current one which is not above. <troot> is already initialised to
	* the parent's branches.
	*/
	while (eb_gettag(troot) == EB_LEFT) {
	/* Walking up from left branch. We must ensure that we never
	* walk beyond root.
	*/
	if (unlikely(eb_clrtag((eb_untag(troot, EB_LEFT))->b[EB_RGHT]) == NULL))
	return NULL;
	troot = (eb_root_to_node(eb_untag(troot, EB_LEFT)))->node_p;
	}
	/* Note that <troot> cannot be NULL at this stage */
	troot = (eb_untag(troot, EB_RGHT))->b[EB_LEFT];
	node = eb32_entry(eb_walk_down(troot, EB_RGHT), struct eb32_node, node);
	return node;
	}

	/*
	* Find the first occurrence of the lowest key in the tree <root>, which is
	* equal to or greater than <x>. NULL is returned is no key matches.
	*/
	REGPRM2 struct eb32_node eb32_lookup_ge(struct eb_root root, u32 x)
	{
	struct eb32_node *node;
	eb_troot_t *troot;

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

	while (1) {
	if ((eb_gettag(troot) == EB_LEAF)) {
	/* We reached a leaf, which means that the whole upper
	* parts were common. We will return either the current
	* node or its next one if the former is too small.
	*/
	node = container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	if (node->key >= x)
	return node;
	/* return next */
	troot = node->node.leaf_p;
	break;
	}
	node = container_of(eb_untag(troot, EB_NODE),
	struct eb32_node, node.branches);

	if (node->node.bit < 0) {
	/* We're at the top of a dup tree. Either we got a
	* matching value and we return the leftmost node, or
	* we don't and we skip the whole subtree to return the
	* next node after the subtree. Note that since we're
	* at the top of the dup tree, we can simply return the
	* next node without first trying to escape from the
	* tree.
	*/
	if (node->key >= x) {
	troot = node->node.branches.b[EB_LEFT];
	while (eb_gettag(troot) != EB_LEAF)
	troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
	return container_of(eb_untag(troot, EB_LEAF),
	struct eb32_node, node.branches);
	}
	/* return next */
	troot = node->node.node_p;
	break;
	}

	if (((x ^ node->key) >> node->node.bit) >= EB_NODE_BRANCHES) {
	/* No more common bits at all. Either this node is too
	* large and we need to get its lowest value, or it is too
	* small, and we need to get the next value.
	*/
	if ((node->key >> node->node.bit) > (x >> node->node.bit)) {
	troot = node->node.branches.b[EB_LEFT];
	return eb32_entry(eb_walk_down(troot, EB_LEFT), struct eb32_node, node);
	}

	/* Further values will be too low here, so return the next
	* unique node (if it exists).
	*/
	troot = node->node.node_p;
	break;
	}
	troot = node->node.branches.b[(x >> node->node.bit) & EB_NODE_BRANCH_MASK];
	}

	/* If we get here, it means we want to report next node after the
	* current one which is not below. <troot> is already initialised
	* to the parent's branches.
	*/
	while (eb_gettag(troot) != EB_LEFT)
	/* Walking up from right branch, so we cannot be below root */
	troot = (eb_root_to_node(eb_untag(troot, EB_RGHT)))->node_p;

	/* Note that <troot> cannot be NULL at this stage */
	troot = (eb_untag(troot, EB_LEFT))->b[EB_RGHT];
	if (eb_clrtag(troot) == NULL)
	return NULL;

	node = eb32_entry(eb_walk_down(troot, EB_LEFT), struct eb32_node, node);
	return node;
	}