From: Florian Forster <octo@crystal.wlan.home.verplant.org>
Date: Wed, 14 Feb 2007 21:32:48 +0000 (+0100)
Subject: Merge branch 'ff/avl-tree'
X-Git-Tag: collectd-4.0.0~187
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=cb7fed8bf0af2646dfcb32844933398c28e39be5;hp=ea57ed17ce9c31ec685f29b9f1bd0698da832415;p=collectd.git

Merge branch 'ff/avl-tree'
---

diff --git a/src/Makefile.am b/src/Makefile.am
index 58cd53ce..f4c5464a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -12,6 +12,7 @@ bin_PROGRAMS = collectd-nagios
 
 collectd_SOURCES = collectd.c collectd.h \
 		   utils_debug.c utils_debug.h \
+		   utils_avltree.c utils_avltree.h \
 		   utils_mount.c utils_mount.h \
 		   utils_llist.c utils_llist.h \
 		   utils_ignorelist.c utils_ignorelist.h \
diff --git a/src/utils_avltree.c b/src/utils_avltree.c
new file mode 100644
index 00000000..4763d234
--- /dev/null
+++ b/src/utils_avltree.c
@@ -0,0 +1,661 @@
+/**
+ * collectd - src/utils_avltree.c
+ * Copyright (C) 2006,2007  Florian octo Forster
+ *
+ * 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
+ *
+ * Authors:
+ *   Florian octo Forster <octo at verplant.org>
+ **/
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+
+#include "utils_avltree.h"
+
+#define BALANCE(n) ((((n)->left == NULL) ? 0 : (n)->left->height) \
+		- (((n)->right == NULL) ? 0 : (n)->right->height))
+
+/*
+ * private data types
+ */
+struct avl_node_s
+{
+	void *key;
+	void *value;
+
+	int height;
+	struct avl_node_s *left;
+	struct avl_node_s *right;
+	struct avl_node_s *parent;
+};
+typedef struct avl_node_s avl_node_t;
+
+struct avl_tree_s
+{
+	avl_node_t *root;
+	int (*compare) (const void *, const void *);
+};
+
+struct avl_iterator_s
+{
+	avl_tree_t *tree;
+	avl_node_t *node;
+};
+
+/*
+ * private functions
+ */
+#if 0
+static void verify_tree (avl_node_t *n)
+{
+	if (n == NULL)
+		return;
+
+	verify_tree (n->left);
+	verify_tree (n->right);
+
+	assert ((BALANCE (n) >= -1) && (BALANCE (n) <= 1));
+	assert ((n->parent == NULL) || (n->parent->right == n) || (n->parent->left == n));
+} /* void verify_tree */
+#else
+# define verify_tree(n) /**/
+#endif
+
+static void free_node (avl_node_t *n)
+{
+	if (n == NULL)
+		return;
+
+	if (n->left != NULL)
+		free_node (n->left);
+	if (n->right != NULL)
+		free_node (n->right);
+
+	free (n);
+}
+
+static int calc_height (avl_node_t *n)
+{
+	int height_left;
+	int height_right;
+
+	if (n == NULL)
+		return (0);
+
+	height_left  = (n->left == NULL)  ? 0 : n->left->height;
+	height_right = (n->right == NULL) ? 0 : n->right->height;
+
+	return (((height_left > height_right)
+				? height_left
+				: height_right) + 1);
+} /* int calc_height */
+
+static avl_node_t *search (avl_tree_t *t, const void *key)
+{
+	avl_node_t *n;
+	int cmp;
+
+	n = t->root;
+	while (n != NULL)
+	{
+		cmp = t->compare (key, n->key);
+		if (cmp == 0)
+			return (n);
+		else if (cmp < 0)
+			n = n->left;
+		else
+			n = n->right;
+	}
+
+	return (NULL);
+}
+
+/*         (x)             (y)
+ *        /   \           /   \
+ *     (y)    /\         /\    (x)
+ *    /   \  /_c\  ==>  / a\  /   \
+ *   /\   /\           /____\/\   /\
+ *  / a\ /_b\               /_b\ /_c\
+ * /____\
+ */
+static avl_node_t *rotate_right (avl_tree_t *t, avl_node_t *x)
+{
+	avl_node_t *p;
+	avl_node_t *y;
+	avl_node_t *b;
+
+	p = x->parent;
+	y = x->left;
+	b = y->right;
+
+	x->left = b;
+	if (b != NULL)
+		b->parent = x;
+
+	x->parent = y;
+	y->right = x;
+
+	y->parent = p;
+	assert ((p == NULL) || (p->left == x) || (p->right == x));
+	if (p == NULL)
+		t->root = y;
+	else if (p->left == x)
+		p->left = y;
+	else
+		p->right = y;
+
+	x->height = calc_height (x);
+	y->height = calc_height (y);
+
+	return (y);
+} /* void rotate_left */
+
+/*
+ *    (x)                   (y)
+ *   /   \                 /   \
+ *  /\    (y)           (x)    /\
+ * /_a\  /   \   ==>   /   \  / c\
+ *      /\   /\       /\   /\/____\
+ *     /_b\ / c\     /_a\ /_b\
+ *         /____\
+ */
+static avl_node_t *rotate_left (avl_tree_t *t, avl_node_t *x)
+{
+	avl_node_t *p;
+	avl_node_t *y;
+	avl_node_t *b;
+
+	p = x->parent;
+	y = x->right;
+	b = y->left;
+
+	x->right = b;
+	if (b != NULL)
+		b->parent = x;
+
+	x->parent = y;
+	y->left = x;
+
+	y->parent = p;
+	assert ((p == NULL) || (p->left == x) || (p->right == x));
+	if (p == NULL)
+		t->root = y;
+	else if (p->left == x)
+		p->left = y;
+	else
+		p->right = y;
+
+	x->height = calc_height (x);
+	y->height = calc_height (y);
+
+	return (y);
+} /* void rotate_left */
+
+static avl_node_t *rotate_left_right (avl_tree_t *t, avl_node_t *x)
+{
+	rotate_left (t, x->left);
+	return (rotate_right (t, x));
+} /* void rotate_left_right */
+
+static avl_node_t *rotate_right_left (avl_tree_t *t, avl_node_t *x)
+{
+	rotate_right (t, x->right);
+	return (rotate_left (t, x));
+} /* void rotate_right_left */
+
+static void rebalance (avl_tree_t *t, avl_node_t *n)
+{
+	int b_top;
+	int b_bottom;
+
+	while (n != NULL)
+	{
+		b_top = BALANCE (n);
+		assert ((b_top >= -2) && (b_top <= 2));
+
+		if (b_top == -2)
+		{
+			assert (n->right != NULL);
+			b_bottom = BALANCE (n->right);
+			assert ((b_bottom >= -1) || (b_bottom <= 1));
+			if (b_bottom == 1)
+				n = rotate_right_left (t, n);
+			else
+				n = rotate_left (t, n);
+		}
+		else if (b_top == 2)
+		{
+			assert (n->left != NULL);
+			b_bottom = BALANCE (n->left);
+			assert ((b_bottom >= -1) || (b_bottom <= 1));
+			if (b_bottom == -1)
+				n = rotate_left_right (t, n);
+			else
+				n = rotate_right (t, n);
+		}
+		else
+		{
+			int height = calc_height (n);
+			if (height == n->height)
+				break;
+			n->height = height;
+		}
+
+		assert (n->height == calc_height (n));
+
+		n = n->parent;
+	} /* while (n != NULL) */
+} /* void rebalance */
+
+static avl_iterator_t *avl_create_iterator (avl_tree_t *t, avl_node_t *n)
+{
+	avl_iterator_t *iter;
+
+	iter = (avl_iterator_t *) malloc (sizeof (avl_iterator_t));
+	if (iter == NULL)
+		return (NULL);
+
+	iter->tree = t;
+	iter->node = n;
+
+	return (iter);
+}
+
+void *avl_node_next (avl_tree_t *t, avl_node_t *n)
+{
+	avl_node_t *r; /* return node */
+
+	if (n == NULL)
+	{
+		return (NULL);
+	}
+	else if (n->right == NULL)
+	{
+
+		r = n->parent;
+		while (r != NULL)
+		{
+			/* stop if a bigger node is found */
+			if (t->compare (n, r) < 0) /* n < r */
+				break;
+			r = r->parent;
+		}
+	}
+	else
+	{
+		r = n->right;
+		while (r->left != NULL)
+			r = r->left;
+	}
+
+	return (r);
+}
+
+void *avl_node_prev (avl_tree_t *t, avl_node_t *n)
+{
+	avl_node_t *r; /* return node */
+
+	if (n == NULL)
+	{
+		return (NULL);
+	}
+	else if (n->left == NULL)
+	{
+
+		r = n->parent;
+		while (r != NULL)
+		{
+			/* stop if a smaller node is found */
+			if (t->compare (n, r) > 0) /* n > r */
+				break;
+			r = r->parent;
+		}
+	}
+	else
+	{
+		r = n->left;
+		while (r->right != NULL)
+			r = r->right;
+	}
+
+	return (r);
+} /* void *avl_node_prev */
+
+static int _remove (avl_tree_t *t, avl_node_t *n)
+{
+	assert ((t != NULL) && (n != NULL));
+
+	if ((n->left != NULL) && (n->right != NULL))
+	{
+		avl_node_t *r; /* replacement node */
+		if (BALANCE (n) > 0) /* left subtree is higher */
+		{
+			assert (n->left != NULL);
+			r = avl_node_prev (t, n);
+			
+		}
+		else /* right subtree is higher */
+		{
+			assert (n->right != NULL);
+			r = avl_node_next (t, n);
+		}
+
+		assert ((r->left == NULL) || (r->right == NULL));
+
+		/* copy content */
+		n->key   = r->key;
+		n->value = r->value;
+
+		n = r;
+	}
+
+	assert ((n->left == NULL) || (n->right == NULL));
+
+	if ((n->left == NULL) && (n->right == NULL))
+	{
+		/* Deleting a leave is easy */
+		if (n->parent == NULL)
+		{
+			assert (t->root == n);
+			t->root = NULL;
+		}
+		else
+		{
+			assert ((n->parent->left == n)
+					|| (n->parent->right == n));
+			if (n->parent->left == n)
+				n->parent->left = NULL;
+			else
+				n->parent->right = NULL;
+
+			rebalance (t, n->parent);
+		}
+
+		free_node (n);
+	}
+	else if (n->left == NULL)
+	{
+		assert (BALANCE (n) == -1);
+		assert ((n->parent == NULL) || (n->parent->left == n) || (n->parent->right == n));
+		if (n->parent == NULL)
+		{
+			assert (t->root == n);
+			t->root = n->right;
+		}
+		else if (n->parent->left == n)
+		{
+			n->parent->left = n->right;
+		}
+		else
+		{
+			n->parent->right = n->right;
+		}
+		n->right->parent = n->parent;
+
+		if (n->parent != NULL)
+			rebalance (t, n->parent);
+
+		n->right = NULL;
+		free_node (n);
+	}
+	else if (n->right == NULL)
+	{
+		assert (BALANCE (n) == 1);
+		assert ((n->parent == NULL) || (n->parent->left == n) || (n->parent->right == n));
+		if (n->parent == NULL)
+		{
+			assert (t->root == n);
+			t->root = n->left;
+		}
+		else if (n->parent->left == n)
+		{
+			n->parent->left = n->left;
+		}
+		else
+		{
+			n->parent->right = n->left;
+		}
+		n->left->parent = n->parent;
+
+		if (n->parent != NULL)
+			rebalance (t, n->parent);
+
+		n->left = NULL;
+		free_node (n);
+	}
+	else
+	{
+		assert (0);
+	}
+
+	return (0);
+} /* void *_remove */
+
+/*
+ * public functions
+ */
+avl_tree_t *avl_create (int (*compare) (const void *, const void *))
+{
+	avl_tree_t *t;
+
+	if ((t = (avl_tree_t *) malloc (sizeof (avl_tree_t))) == NULL)
+		return (NULL);
+
+	t->root = NULL;
+	t->compare = compare;
+
+	return (t);
+}
+
+void avl_destroy (avl_tree_t *t)
+{
+	free_node (t->root);
+	free (t);
+}
+
+int avl_insert (avl_tree_t *t, void *key, void *value)
+{
+	avl_node_t *new;
+	avl_node_t *nptr;
+	int cmp;
+
+	if ((new = (avl_node_t *) malloc (sizeof (avl_node_t))) == NULL)
+		return (-1);
+
+	new->key = key;
+	new->value = value;
+	new->height = 1;
+	new->left = NULL;
+	new->right = NULL;
+
+	if (t->root == NULL)
+	{
+		new->parent = NULL;
+		t->root = new;
+		return (0);
+	}
+
+	nptr = t->root;
+	while (42)
+	{
+		cmp = t->compare (nptr->key, new->key);
+		if (cmp == 0)
+		{
+			free_node (new);
+			return (-1);
+		}
+		else if (cmp < 0)
+		{
+			/* nptr < new */
+			if (nptr->right == NULL)
+			{
+				nptr->right = new;
+				new->parent = nptr;
+				rebalance (t, nptr);
+				break;
+			}
+			else
+			{
+				nptr = nptr->right;
+			}
+		}
+		else /* if (cmp > 0) */
+		{
+			/* nptr > new */
+			if (nptr->left == NULL)
+			{
+				nptr->left = new;
+				new->parent = nptr;
+				rebalance (t, nptr);
+				break;
+			}
+			else
+			{
+				nptr = nptr->left;
+			}
+		}
+	} /* while (42) */
+
+	verify_tree (t->root);
+	return (0);
+} /* int avl_insert */
+
+int avl_remove (avl_tree_t *t, void *key, void **rkey, void **rvalue)
+{
+	avl_node_t *n;
+	int status;
+
+	assert (t != NULL);
+
+	n = search (t, key);
+	if (n == NULL)
+		return (-1);
+
+	if (rkey != NULL)
+		*rkey = n->key;
+	if (rvalue != NULL)
+		*rvalue = n->value;
+
+	status = _remove (t, n);
+	verify_tree (t->root);
+	return (status);
+} /* void *avl_remove */
+
+int avl_get (avl_tree_t *t, const void *key, void **value)
+{
+	avl_node_t *n;
+
+	assert (value != NULL);
+
+	n = search (t, key);
+	if (n == NULL)
+		return (-1);
+
+	*value = n->value;
+
+	return (0);
+}
+
+avl_iterator_t *avl_get_iterator (avl_tree_t *t)
+{
+	avl_node_t *n;
+
+	if (t == NULL)
+		return (NULL);
+
+	for (n = t->root; n != NULL; n = n->left)
+		if (n->left == NULL)
+			break;
+
+	return (avl_create_iterator (t, n));
+} /* avl_iterator_t *avl_get_iterator */
+
+int avl_pick (avl_tree_t *, void **key, void **value)
+{
+	avl_node_t *n;
+	avl_node_t *p;
+
+	assert ((key != NULL) && (value != NULL));
+	if (t->root == NULL)
+		return (-1);
+
+	n = t->root;
+	while ((n->left != NULL) || (n->right != NULL))
+	{
+		int height_left  = (n->left  == NULL) ? 0 : n->left->traffic;
+		int height_right = (n->right == NULL) ? 0 : n->right->traffic;
+
+		if (height_left > height_right)
+			n = n->left;
+		else
+			n = n->right;
+	}
+
+	p = n->parent;
+	if (p == NULL)
+		t->root = NULL;
+	else if (p->left == n)
+		p->left = NULL;
+	else
+		p->right = NULL;
+
+	*key   = n->key;
+	*value = n->value;
+
+	free_node (n);
+	rebalance (p);
+
+	return (0);
+} /* int avl_pick */
+
+void *avl_iterator_next (avl_iterator_t *iter)
+{
+	avl_node_t *n;
+
+	if ((iter == NULL) || (iter->node == NULL))
+		return (NULL);
+
+	n = avl_node_next (iter->tree, iter->node);
+
+	if (n == NULL)
+		return (NULL);
+
+	iter->node = n;
+	return (n);
+
+}
+
+void *avl_iterator_prev (avl_iterator_t *iter)
+{
+	avl_node_t *n;
+
+	if ((iter == NULL) || (iter->node == NULL))
+		return (NULL);
+
+	n = avl_node_prev (iter->tree, iter->node);
+
+	if (n == NULL)
+		return (NULL);
+
+	iter->node = n;
+	return (n);
+
+}
+
+void avl_iterator_destroy (avl_iterator_t *iter)
+{
+	free (iter);
+}
diff --git a/src/utils_avltree.h b/src/utils_avltree.h
new file mode 100644
index 00000000..7875e0b2
--- /dev/null
+++ b/src/utils_avltree.h
@@ -0,0 +1,29 @@
+#ifndef UTILS_AVLTREE_H
+#define UTILS_AVLTREE_H 1
+
+struct avl_tree_s;
+typedef struct avl_tree_s avl_tree_t;
+
+struct avl_iterator_s;
+typedef struct avl_iterator_s avl_iterator_t;
+
+struct avl_keyval_s
+{
+	void *key;
+	void *value;
+};
+
+avl_tree_t *avl_create (int (*compare) (const void *, const void *));
+void avl_destroy (avl_tree_t *t);
+
+int avl_insert (avl_tree_t *t, void *key, void *value);
+int avl_remove (avl_tree_t *t, void *key, void **rkey, void **rvalue);
+
+int avl_get (avl_tree_t *t, const void *key, void **value);
+
+avl_iterator_t *avl_get_iterator (avl_tree_t *t);
+void *avl_iterator_next (avl_iterator_t *iter);
+void *avl_iterator_prev (avl_iterator_t *iter);
+void avl_iterator_destroy (avl_iterator_t *iter);
+
+#endif /* UTILS_AVLTREE_H */