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2b5702030d
Sometimes it's very useful to visit duplicates of a same node, but doing so from the application is not convenient because keys have to be compared, while all the information is available during the next/prev steps. Let's introduce a couple of new eb_next_dup/eb_prev_dup functions to visit only duplicates of the current node and return NULL once it's done. Now we have all 3 combinations : - next : returns next node in the tree - next_dup : returns next dup in the sub-tree - next_unique : returns next value after skipping dups (cherry picked from commit 3327b8ae6866f3878322a1a29e70b450226d216d)
500 lines
16 KiB
C
500 lines
16 KiB
C
/*
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* Elastic Binary Trees - macros and structures for operations on 32bit nodes.
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* Version 6.0.6
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* (C) 2002-2011 - Willy Tarreau <w@1wt.eu>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _EB32TREE_H
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#define _EB32TREE_H
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#include "ebtree.h"
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/* Return the structure of type <type> whose member <member> points to <ptr> */
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#define eb32_entry(ptr, type, member) container_of(ptr, type, member)
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#define EB32_ROOT EB_ROOT
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#define EB32_TREE_HEAD EB_TREE_HEAD
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/* These types may sometimes already be defined */
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typedef unsigned int u32;
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typedef signed int s32;
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/* This structure carries a node, a leaf, and a key. It must start with the
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* eb_node so that it can be cast into an eb_node. We could also have put some
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* sort of transparent union here to reduce the indirection level, but the fact
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* is, the end user is not meant to manipulate internals, so this is pointless.
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*/
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struct eb32_node {
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struct eb_node node; /* the tree node, must be at the beginning */
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u32 key;
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};
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/*
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* Exported functions and macros.
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* Many of them are always inlined because they are extremely small, and
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* are generally called at most once or twice in a program.
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*/
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/* Return leftmost node in the tree, or NULL if none */
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static inline struct eb32_node *eb32_first(struct eb_root *root)
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{
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return eb32_entry(eb_first(root), struct eb32_node, node);
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}
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/* Return rightmost node in the tree, or NULL if none */
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static inline struct eb32_node *eb32_last(struct eb_root *root)
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{
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return eb32_entry(eb_last(root), struct eb32_node, node);
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}
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/* Return next node in the tree, or NULL if none */
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static inline struct eb32_node *eb32_next(struct eb32_node *eb32)
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{
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return eb32_entry(eb_next(&eb32->node), struct eb32_node, node);
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}
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/* Return previous node in the tree, or NULL if none */
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static inline struct eb32_node *eb32_prev(struct eb32_node *eb32)
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{
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return eb32_entry(eb_prev(&eb32->node), struct eb32_node, node);
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}
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/* Return next leaf node within a duplicate sub-tree, or NULL if none. */
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static inline struct eb32_node *eb32_next_dup(struct eb32_node *eb32)
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{
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return eb32_entry(eb_next_dup(&eb32->node), struct eb32_node, node);
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}
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/* Return previous leaf node within a duplicate sub-tree, or NULL if none. */
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static inline struct eb32_node *eb32_prev_dup(struct eb32_node *eb32)
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{
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return eb32_entry(eb_prev_dup(&eb32->node), struct eb32_node, node);
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}
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/* Return next node in the tree, skipping duplicates, or NULL if none */
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static inline struct eb32_node *eb32_next_unique(struct eb32_node *eb32)
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{
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return eb32_entry(eb_next_unique(&eb32->node), struct eb32_node, node);
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}
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/* Return previous node in the tree, skipping duplicates, or NULL if none */
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static inline struct eb32_node *eb32_prev_unique(struct eb32_node *eb32)
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{
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return eb32_entry(eb_prev_unique(&eb32->node), struct eb32_node, node);
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}
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/* Delete node from the tree if it was linked in. Mark the node unused. Note
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* that this function relies on a non-inlined generic function: eb_delete.
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*/
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static inline void eb32_delete(struct eb32_node *eb32)
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{
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eb_delete(&eb32->node);
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}
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/*
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* The following functions are not inlined by default. They are declared
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* in eb32tree.c, which simply relies on their inline version.
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*/
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REGPRM2 struct eb32_node *eb32_lookup(struct eb_root *root, u32 x);
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REGPRM2 struct eb32_node *eb32i_lookup(struct eb_root *root, s32 x);
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REGPRM2 struct eb32_node *eb32_lookup_le(struct eb_root *root, u32 x);
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REGPRM2 struct eb32_node *eb32_lookup_ge(struct eb_root *root, u32 x);
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REGPRM2 struct eb32_node *eb32_insert(struct eb_root *root, struct eb32_node *new);
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REGPRM2 struct eb32_node *eb32i_insert(struct eb_root *root, struct eb32_node *new);
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/*
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* The following functions are less likely to be used directly, because their
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* code is larger. The non-inlined version is preferred.
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*/
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/* Delete node from the tree if it was linked in. Mark the node unused. */
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static forceinline void __eb32_delete(struct eb32_node *eb32)
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{
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__eb_delete(&eb32->node);
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}
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/*
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* Find the first occurence of a key in the tree <root>. If none can be
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* found, return NULL.
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*/
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static forceinline struct eb32_node *__eb32_lookup(struct eb_root *root, u32 x)
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{
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struct eb32_node *node;
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eb_troot_t *troot;
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u32 y;
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int node_bit;
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troot = root->b[EB_LEFT];
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if (unlikely(troot == NULL))
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return NULL;
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while (1) {
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if ((eb_gettag(troot) == EB_LEAF)) {
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node = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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if (node->key == x)
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return node;
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else
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return NULL;
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}
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node = container_of(eb_untag(troot, EB_NODE),
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struct eb32_node, node.branches);
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node_bit = node->node.bit;
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y = node->key ^ x;
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if (!y) {
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/* Either we found the node which holds the key, or
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* we have a dup tree. In the later case, we have to
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* walk it down left to get the first entry.
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*/
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if (node_bit < 0) {
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troot = node->node.branches.b[EB_LEFT];
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while (eb_gettag(troot) != EB_LEAF)
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troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
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node = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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}
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return node;
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}
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if ((y >> node_bit) >= EB_NODE_BRANCHES)
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return NULL; /* no more common bits */
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troot = node->node.branches.b[(x >> node_bit) & EB_NODE_BRANCH_MASK];
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}
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}
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/*
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* Find the first occurence of a signed key in the tree <root>. If none can
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* be found, return NULL.
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*/
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static forceinline struct eb32_node *__eb32i_lookup(struct eb_root *root, s32 x)
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{
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struct eb32_node *node;
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eb_troot_t *troot;
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u32 key = x ^ 0x80000000;
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u32 y;
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int node_bit;
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troot = root->b[EB_LEFT];
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if (unlikely(troot == NULL))
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return NULL;
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while (1) {
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if ((eb_gettag(troot) == EB_LEAF)) {
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node = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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if (node->key == (u32)x)
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return node;
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else
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return NULL;
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}
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node = container_of(eb_untag(troot, EB_NODE),
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struct eb32_node, node.branches);
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node_bit = node->node.bit;
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y = node->key ^ x;
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if (!y) {
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/* Either we found the node which holds the key, or
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* we have a dup tree. In the later case, we have to
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* walk it down left to get the first entry.
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*/
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if (node_bit < 0) {
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troot = node->node.branches.b[EB_LEFT];
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while (eb_gettag(troot) != EB_LEAF)
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troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
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node = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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}
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return node;
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}
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if ((y >> node_bit) >= EB_NODE_BRANCHES)
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return NULL; /* no more common bits */
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troot = node->node.branches.b[(key >> node_bit) & EB_NODE_BRANCH_MASK];
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}
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}
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/* Insert eb32_node <new> into subtree starting at node root <root>.
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* Only new->key needs be set with the key. The eb32_node is returned.
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* If root->b[EB_RGHT]==1, the tree may only contain unique keys.
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*/
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static forceinline struct eb32_node *
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__eb32_insert(struct eb_root *root, struct eb32_node *new) {
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struct eb32_node *old;
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unsigned int side;
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eb_troot_t *troot, **up_ptr;
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u32 newkey; /* caching the key saves approximately one cycle */
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eb_troot_t *root_right;
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eb_troot_t *new_left, *new_rght;
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eb_troot_t *new_leaf;
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int old_node_bit;
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side = EB_LEFT;
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troot = root->b[EB_LEFT];
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root_right = root->b[EB_RGHT];
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if (unlikely(troot == NULL)) {
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/* Tree is empty, insert the leaf part below the left branch */
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root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
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new->node.leaf_p = eb_dotag(root, EB_LEFT);
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new->node.node_p = NULL; /* node part unused */
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return new;
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}
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/* The tree descent is fairly easy :
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* - first, check if we have reached a leaf node
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* - second, check if we have gone too far
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* - third, reiterate
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* Everywhere, we use <new> for the node node we are inserting, <root>
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* for the node we attach it to, and <old> for the node we are
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* displacing below <new>. <troot> will always point to the future node
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* (tagged with its type). <side> carries the side the node <new> is
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* attached to below its parent, which is also where previous node
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* was attached. <newkey> carries the key being inserted.
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*/
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newkey = new->key;
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while (1) {
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if (eb_gettag(troot) == EB_LEAF) {
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/* insert above a leaf */
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old = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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new->node.node_p = old->node.leaf_p;
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up_ptr = &old->node.leaf_p;
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break;
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}
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/* OK we're walking down this link */
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old = container_of(eb_untag(troot, EB_NODE),
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struct eb32_node, node.branches);
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old_node_bit = old->node.bit;
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/* Stop going down when we don't have common bits anymore. We
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* also stop in front of a duplicates tree because it means we
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* have to insert above.
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*/
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if ((old_node_bit < 0) || /* we're above a duplicate tree, stop here */
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(((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
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/* The tree did not contain the key, so we insert <new> before the node
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* <old>, and set ->bit to designate the lowest bit position in <new>
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* which applies to ->branches.b[].
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*/
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new->node.node_p = old->node.node_p;
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up_ptr = &old->node.node_p;
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break;
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}
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/* walk down */
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root = &old->node.branches;
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side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
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troot = root->b[side];
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}
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new_left = eb_dotag(&new->node.branches, EB_LEFT);
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new_rght = eb_dotag(&new->node.branches, EB_RGHT);
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new_leaf = eb_dotag(&new->node.branches, EB_LEAF);
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/* We need the common higher bits between new->key and old->key.
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* What differences are there between new->key and the node here ?
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* NOTE that bit(new) is always < bit(root) because highest
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* bit of new->key and old->key are identical here (otherwise they
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* would sit on different branches).
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*/
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// note that if EB_NODE_BITS > 1, we should check that it's still >= 0
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new->node.bit = flsnz(new->key ^ old->key) - EB_NODE_BITS;
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if (new->key == old->key) {
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new->node.bit = -1; /* mark as new dup tree, just in case */
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if (likely(eb_gettag(root_right))) {
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/* we refuse to duplicate this key if the tree is
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* tagged as containing only unique keys.
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*/
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return old;
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}
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if (eb_gettag(troot) != EB_LEAF) {
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/* there was already a dup tree below */
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struct eb_node *ret;
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ret = eb_insert_dup(&old->node, &new->node);
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return container_of(ret, struct eb32_node, node);
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}
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/* otherwise fall through */
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}
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if (new->key >= old->key) {
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new->node.branches.b[EB_LEFT] = troot;
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new->node.branches.b[EB_RGHT] = new_leaf;
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new->node.leaf_p = new_rght;
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*up_ptr = new_left;
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}
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else {
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new->node.branches.b[EB_LEFT] = new_leaf;
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new->node.branches.b[EB_RGHT] = troot;
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new->node.leaf_p = new_left;
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*up_ptr = new_rght;
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}
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/* Ok, now we are inserting <new> between <root> and <old>. <old>'s
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* parent is already set to <new>, and the <root>'s branch is still in
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* <side>. Update the root's leaf till we have it. Note that we can also
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* find the side by checking the side of new->node.node_p.
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*/
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root->b[side] = eb_dotag(&new->node.branches, EB_NODE);
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return new;
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}
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/* Insert eb32_node <new> into subtree starting at node root <root>, using
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* signed keys. Only new->key needs be set with the key. The eb32_node
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* is returned. If root->b[EB_RGHT]==1, the tree may only contain unique keys.
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*/
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static forceinline struct eb32_node *
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__eb32i_insert(struct eb_root *root, struct eb32_node *new) {
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struct eb32_node *old;
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unsigned int side;
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eb_troot_t *troot, **up_ptr;
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int newkey; /* caching the key saves approximately one cycle */
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eb_troot_t *root_right;
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eb_troot_t *new_left, *new_rght;
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eb_troot_t *new_leaf;
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int old_node_bit;
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side = EB_LEFT;
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troot = root->b[EB_LEFT];
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root_right = root->b[EB_RGHT];
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if (unlikely(troot == NULL)) {
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/* Tree is empty, insert the leaf part below the left branch */
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root->b[EB_LEFT] = eb_dotag(&new->node.branches, EB_LEAF);
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new->node.leaf_p = eb_dotag(root, EB_LEFT);
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new->node.node_p = NULL; /* node part unused */
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return new;
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}
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/* The tree descent is fairly easy :
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* - first, check if we have reached a leaf node
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* - second, check if we have gone too far
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* - third, reiterate
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* Everywhere, we use <new> for the node node we are inserting, <root>
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* for the node we attach it to, and <old> for the node we are
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* displacing below <new>. <troot> will always point to the future node
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* (tagged with its type). <side> carries the side the node <new> is
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* attached to below its parent, which is also where previous node
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* was attached. <newkey> carries a high bit shift of the key being
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* inserted in order to have negative keys stored before positive
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* ones.
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*/
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newkey = new->key + 0x80000000;
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while (1) {
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if (eb_gettag(troot) == EB_LEAF) {
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old = container_of(eb_untag(troot, EB_LEAF),
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struct eb32_node, node.branches);
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new->node.node_p = old->node.leaf_p;
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up_ptr = &old->node.leaf_p;
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break;
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}
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/* OK we're walking down this link */
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old = container_of(eb_untag(troot, EB_NODE),
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struct eb32_node, node.branches);
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old_node_bit = old->node.bit;
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/* Stop going down when we don't have common bits anymore. We
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* also stop in front of a duplicates tree because it means we
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* have to insert above.
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*/
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if ((old_node_bit < 0) || /* we're above a duplicate tree, stop here */
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(((new->key ^ old->key) >> old_node_bit) >= EB_NODE_BRANCHES)) {
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/* The tree did not contain the key, so we insert <new> before the node
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* <old>, and set ->bit to designate the lowest bit position in <new>
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* which applies to ->branches.b[].
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*/
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new->node.node_p = old->node.node_p;
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up_ptr = &old->node.node_p;
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break;
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}
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/* walk down */
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root = &old->node.branches;
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side = (newkey >> old_node_bit) & EB_NODE_BRANCH_MASK;
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troot = root->b[side];
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}
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new_left = eb_dotag(&new->node.branches, EB_LEFT);
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new_rght = eb_dotag(&new->node.branches, EB_RGHT);
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new_leaf = eb_dotag(&new->node.branches, EB_LEAF);
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/* We need the common higher bits between new->key and old->key.
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* What differences are there between new->key and the node here ?
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* NOTE that bit(new) is always < bit(root) because highest
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* bit of new->key and old->key are identical here (otherwise they
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* would sit on different branches).
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*/
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// 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 */
|