| /* |
| * Elastic Binary Trees - macros and structures for Multi-Byte data nodes. |
| * Version 5.0 |
| * (C) 2002-2009 - Willy Tarreau <w@1wt.eu> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef _EBMBTREE_H |
| #define _EBMBTREE_H |
| |
| #include <string.h> |
| #include "ebtree.h" |
| |
| /* Return the structure of type <type> whose member <member> points to <ptr> */ |
| #define ebmb_entry(ptr, type, member) container_of(ptr, type, member) |
| |
| #define EBMB_ROOT EB_ROOT |
| #define EBMB_TREE_HEAD EB_TREE_HEAD |
| |
| /* 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. |
| * The 'node.bit' value here works differently from scalar types, as it contains |
| * the number of identical bits between the two branches. |
| */ |
| struct ebmb_node { |
| struct eb_node node; /* the tree node, must be at the beginning */ |
| unsigned char key[0]; /* the key, its size depends on the application */ |
| }; |
| |
| /* |
| * 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 forceinline struct ebmb_node *ebmb_first(struct eb_root *root) |
| { |
| return ebmb_entry(eb_first(root), struct ebmb_node, node); |
| } |
| |
| /* Return rightmost node in the tree, or NULL if none */ |
| static forceinline struct ebmb_node *ebmb_last(struct eb_root *root) |
| { |
| return ebmb_entry(eb_last(root), struct ebmb_node, node); |
| } |
| |
| /* Return next node in the tree, or NULL if none */ |
| static forceinline struct ebmb_node *ebmb_next(struct ebmb_node *ebmb) |
| { |
| return ebmb_entry(eb_next(&ebmb->node), struct ebmb_node, node); |
| } |
| |
| /* Return previous node in the tree, or NULL if none */ |
| static forceinline struct ebmb_node *ebmb_prev(struct ebmb_node *ebmb) |
| { |
| return ebmb_entry(eb_prev(&ebmb->node), struct ebmb_node, node); |
| } |
| |
| /* Return next node in the tree, skipping duplicates, or NULL if none */ |
| static forceinline struct ebmb_node *ebmb_next_unique(struct ebmb_node *ebmb) |
| { |
| return ebmb_entry(eb_next_unique(&ebmb->node), struct ebmb_node, node); |
| } |
| |
| /* Return previous node in the tree, skipping duplicates, or NULL if none */ |
| static forceinline struct ebmb_node *ebmb_prev_unique(struct ebmb_node *ebmb) |
| { |
| return ebmb_entry(eb_prev_unique(&ebmb->node), struct ebmb_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 forceinline void ebmb_delete(struct ebmb_node *ebmb) |
| { |
| eb_delete(&ebmb->node); |
| } |
| |
| /* The following functions are not inlined by default. They are declared |
| * in ebmbtree.c, which simply relies on their inline version. |
| */ |
| REGPRM3 struct ebmb_node *ebmb_lookup(struct eb_root *root, const void *x, unsigned int len); |
| REGPRM3 struct ebmb_node *ebmb_insert(struct eb_root *root, struct ebmb_node *new, unsigned int len); |
| |
| /* 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 __ebmb_delete(struct ebmb_node *ebmb) |
| { |
| __eb_delete(&ebmb->node); |
| } |
| |
| /* Find the first occurence of a key of <len> bytes in the tree <root>. |
| * If none can be found, return NULL. |
| */ |
| static forceinline struct ebmb_node *__ebmb_lookup(struct eb_root *root, const void *x, unsigned int len) |
| { |
| struct ebmb_node *node; |
| eb_troot_t *troot; |
| unsigned int bit; |
| |
| troot = root->b[EB_LEFT]; |
| if (unlikely(troot == NULL)) |
| return NULL; |
| |
| bit = 0; |
| while (1) { |
| if ((eb_gettag(troot) == EB_LEAF)) { |
| node = container_of(eb_untag(troot, EB_LEAF), |
| struct ebmb_node, node.branches); |
| if (memcmp(node->key, x, len) == 0) |
| return node; |
| else |
| return NULL; |
| } |
| node = container_of(eb_untag(troot, EB_NODE), |
| struct ebmb_node, node.branches); |
| |
| if (node->node.bit < 0) { |
| /* We have a dup tree now. Either it's for the same |
| * value, and we walk down left, or it's a different |
| * one and we don't have our key. |
| */ |
| if (memcmp(node->key, x, len) != 0) |
| return NULL; |
| |
| 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 ebmb_node, node.branches); |
| return node; |
| } |
| |
| /* OK, normal data node, let's walk down */ |
| bit = equal_bits(x, node->key, bit, node->node.bit); |
| if (bit < node->node.bit) |
| return NULL; /* no more common bits */ |
| |
| troot = node->node.branches.b[(((unsigned char*)x)[node->node.bit >> 3] >> |
| (~node->node.bit & 7)) & 1]; |
| } |
| } |
| |
| /* Insert ebmb_node <new> into subtree starting at node root <root>. |
| * Only new->key needs be set with the key. The ebmb_node is returned. |
| * If root->b[EB_RGHT]==1, the tree may only contain unique keys. The |
| * len is specified in bytes. |
| */ |
| static forceinline struct ebmb_node * |
| __ebmb_insert(struct eb_root *root, struct ebmb_node *new, unsigned int len) |
| { |
| struct ebmb_node *old; |
| unsigned int side; |
| eb_troot_t *troot; |
| eb_troot_t *root_right = root; |
| int diff; |
| int 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; |
| } |
| |
| len <<= 3; |
| |
| /* 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. |
| */ |
| |
| bit = 0; |
| while (1) { |
| if (unlikely(eb_gettag(troot) == EB_LEAF)) { |
| eb_troot_t *new_left, *new_rght; |
| eb_troot_t *new_leaf, *old_leaf; |
| |
| old = container_of(eb_untag(troot, EB_LEAF), |
| struct ebmb_node, node.branches); |
| |
| 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); |
| old_leaf = eb_dotag(&old->node.branches, EB_LEAF); |
| |
| new->node.node_p = old->node.leaf_p; |
| |
| /* Right here, we have 3 possibilities : |
| * - the tree does not contain the key, and we have |
| * new->key < old->key. We insert new above old, on |
| * the left ; |
| * |
| * - the tree does not contain the key, and we have |
| * new->key > old->key. We insert new above old, on |
| * the right ; |
| * |
| * - the tree does contain the key, which implies it |
| * is alone. We add the new key next to it as a |
| * first duplicate. |
| * |
| * The last two cases can easily be partially merged. |
| */ |
| bit = equal_bits(new->key, old->key, bit, len); |
| diff = cmp_bits(new->key, old->key, bit); |
| |
| if (diff < 0) { |
| new->node.leaf_p = new_left; |
| old->node.leaf_p = new_rght; |
| new->node.branches.b[EB_LEFT] = new_leaf; |
| new->node.branches.b[EB_RGHT] = old_leaf; |
| } else { |
| /* we may refuse to duplicate this key if the tree is |
| * tagged as containing only unique keys. |
| */ |
| if (diff == 0 && eb_gettag(root_right)) |
| return old; |
| |
| /* new->key >= old->key, new goes the right */ |
| old->node.leaf_p = new_left; |
| new->node.leaf_p = new_rght; |
| new->node.branches.b[EB_LEFT] = old_leaf; |
| new->node.branches.b[EB_RGHT] = new_leaf; |
| |
| if (diff == 0) { |
| new->node.bit = -1; |
| root->b[side] = eb_dotag(&new->node.branches, EB_NODE); |
| return new; |
| } |
| } |
| break; |
| } |
| |
| /* OK we're walking down this link */ |
| old = container_of(eb_untag(troot, EB_NODE), |
| struct ebmb_node, node.branches); |
| |
| /* 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. Note: we can compare more bits than |
| * the current node's because as long as they are identical, we |
| * know we descend along the correct side. |
| */ |
| if (old->node.bit < 0) { |
| /* we're above a duplicate tree, we must compare till the end */ |
| bit = equal_bits(new->key, old->key, bit, len); |
| goto dup_tree; |
| } |
| else if (bit < old->node.bit) { |
| bit = equal_bits(new->key, old->key, bit, old->node.bit); |
| } |
| |
| if (bit < old->node.bit) { /* we don't have all bits in common */ |
| /* 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[]. |
| */ |
| eb_troot_t *new_left, *new_rght; |
| eb_troot_t *new_leaf, *old_node; |
| |
| dup_tree: |
| 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); |
| old_node = eb_dotag(&old->node.branches, EB_NODE); |
| |
| new->node.node_p = old->node.node_p; |
| |
| diff = cmp_bits(new->key, old->key, bit); |
| if (diff < 0) { |
| new->node.leaf_p = new_left; |
| old->node.node_p = new_rght; |
| new->node.branches.b[EB_LEFT] = new_leaf; |
| new->node.branches.b[EB_RGHT] = old_node; |
| } |
| else if (diff > 0) { |
| old->node.node_p = new_left; |
| new->node.leaf_p = new_rght; |
| new->node.branches.b[EB_LEFT] = old_node; |
| new->node.branches.b[EB_RGHT] = new_leaf; |
| } |
| else { |
| struct eb_node *ret; |
| ret = eb_insert_dup(&old->node, &new->node); |
| return container_of(ret, struct ebmb_node, node); |
| } |
| break; |
| } |
| |
| /* walk down */ |
| root = &old->node.branches; |
| side = (new->key[old->node.bit >> 3] >> (~old->node.bit & 7)) & 1; |
| troot = root->b[side]; |
| } |
| |
| /* 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. |
| */ |
| |
| /* We need the common higher bits between new->key and old->key. |
| * This number of bits is already in <bit>. |
| */ |
| new->node.bit = bit; |
| root->b[side] = eb_dotag(&new->node.branches, EB_NODE); |
| return new; |
| } |
| |
| #endif /* _EBMBTREE_H */ |
| |