Adding upstream version 2.6.12.upstream/2.6.12upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 324 insertions, 0 deletions

diff --git a/include/import/ebimtree.h b/include/import/ebimtree.h
new file mode 100644
index 0000000..0afbdd1
--- /dev/null
+++ b/include/import/ebimtree.h
@@ -0,0 +1,324 @@
+/*
+ * Elastic Binary Trees - macros for Indirect Multi-Byte data 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 _EBIMTREE_H
+#define _EBIMTREE_H
+
+#include <string.h>
+#include "ebtree.h"
+#include "ebpttree.h"
+
+/* These functions and macros rely on Pointer nodes and use the <key> entry as
+ * a pointer to an indirect key. Most operations are performed using ebpt_*.
+ */
+
+/* The following functions are not inlined by default. They are declared
+ * in ebimtree.c, which simply relies on their inline version.
+ */
+struct ebpt_node *ebim_lookup(struct eb_root *root, const void *x, unsigned int len);
+struct ebpt_node *ebim_insert(struct eb_root *root, struct ebpt_node *new, unsigned int len);
+
+/* Find the first occurrence of a key of a least <len> bytes matching <x> in the
+ * tree <root>. The caller is responsible for ensuring that <len> will not exceed
+ * the common parts between the tree's keys and <x>. In case of multiple matches,
+ * the leftmost node is returned. This means that this function can be used to
+ * lookup string keys by prefix if all keys in the tree are zero-terminated. If
+ * no match is found, NULL is returned. Returns first node if <len> is zero.
+ */
+static forceinline struct ebpt_node *
+__ebim_lookup(struct eb_root *root, const void *x, unsigned int len)
+{
+	struct ebpt_node *node;
+	eb_troot_t *troot;
+	int pos, side;
+	int node_bit;
+
+	troot = root->b[EB_LEFT];
+	if (unlikely(troot == NULL))
+		goto ret_null;
+
+	if (unlikely(len == 0))
+		goto walk_down;
+
+	pos = 0;
+	while (1) {
+		if (eb_gettag(troot) == EB_LEAF) {
+			node = container_of(eb_untag(troot, EB_LEAF),
+					    struct ebpt_node, node.branches);
+			if (eb_memcmp(node->key + pos, x, len) != 0)
+				goto ret_null;
+			else
+				goto ret_node;
+		}
+		node = container_of(eb_untag(troot, EB_NODE),
+				    struct ebpt_node, node.branches);
+
+		node_bit = node->node.bit;
+		if (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 (eb_memcmp(node->key + pos, x, len) != 0)
+				goto ret_null;
+			else
+				goto walk_left;
+		}
+
+		/* OK, normal data node, let's walk down. We check if all full
+		 * bytes are equal, and we start from the last one we did not
+		 * completely check. We stop as soon as we reach the last byte,
+		 * because we must decide to go left/right or abort.
+		 */
+		node_bit = ~node_bit + (pos << 3) + 8; // = (pos<<3) + (7 - node_bit)
+		if (node_bit < 0) {
+			/* This surprising construction gives better performance
+			 * because gcc does not try to reorder the loop. Tested to
+			 * be fine with 2.95 to 4.2.
+			 */
+			while (1) {
+				if (*(unsigned char*)(node->key + pos++) ^ *(unsigned char*)(x++))
+					goto ret_null; /* more than one full byte is different */
+				if (--len == 0)
+					goto walk_left; /* return first node if all bytes matched */
+				node_bit += 8;
+				if (node_bit >= 0)
+					break;
+			}
+		}
+
+		/* here we know that only the last byte differs, so node_bit < 8.
+		 * We have 2 possibilities :
+		 *   - more than the last bit differs => return NULL
+		 *   - walk down on side = (x[pos] >> node_bit) & 1
+		 */
+		side = *(unsigned char *)x >> node_bit;
+		if (((*(unsigned char*)(node->key + pos) >> node_bit) ^ side) > 1)
+			goto ret_null;
+		side &= 1;
+		troot = node->node.branches.b[side];
+	}
+ walk_left:
+	troot = node->node.branches.b[EB_LEFT];
+ walk_down:
+	while (eb_gettag(troot) != EB_LEAF)
+		troot = (eb_untag(troot, EB_NODE))->b[EB_LEFT];
+	node = container_of(eb_untag(troot, EB_LEAF),
+			    struct ebpt_node, node.branches);
+ ret_node:
+	return node;
+ ret_null:
+	return NULL;
+}
+
+/* Insert ebpt_node <new> into subtree starting at node root <root>.
+ * Only new->key needs be set with the key. The ebpt_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 ebpt_node *
+__ebim_insert(struct eb_root *root, struct ebpt_node *new, unsigned int len)
+{
+	struct ebpt_node *old;
+	unsigned int side;
+	eb_troot_t *troot;
+	eb_troot_t *root_right;
+	int diff;
+	int bit;
+	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;
+	}
+
+	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 ebpt_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);
+
+			/* 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. However we don't want to start to compare past the end.
+			 */
+			diff = 0;
+			if (((unsigned)bit >> 3) < 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 ebpt_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. 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;
+
+			/* 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. However we don't want to start to compare past the end.
+			 */
+			diff = 0;
+			if (((unsigned)bit >> 3) < len)
+				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 ebpt_node, node);
+			}
+			break;
+		}
+
+		/* walk down */
+		root = &old->node.branches;
+		side = (((unsigned char *)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 /* _EBIMTREE_H */