From: Guus Sliepen <guus@tinc-vpn.org>
Date: Tue, 2 Nov 2004 20:50:53 +0000 (+0000)
Subject: Splay trees.
X-Git-Tag: import-tinc-1.1~765
X-Git-Url: https://git.meshlink.io/?a=commitdiff_plain;h=719cb95ea4fa7a2e6f4291aed607323f290c7a91;p=meshlink

Splay trees.
---

diff --git a/lib/splay_tree.c b/lib/splay_tree.c
new file mode 100644
index 00000000..1b320cc0
--- /dev/null
+++ b/lib/splay_tree.c
@@ -0,0 +1,560 @@
+/*
+    splay_tree.c -- splay tree and linked list convenience
+    Copyright (C) 2004 Guus Sliepen <guus@tinc-vpn.org>
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    $Id: splay_tree.c 1374 2004-03-21 14:21:22Z guus $
+*/
+
+#include "system.h"
+
+#include "splay_tree.h"
+#include "xalloc.h"
+
+/* Splay operation */
+
+static splay_node_t *splay_top_down(splay_tree_t *tree, const void *data, int *result) {
+	splay_node_t left = {0}, right = {0};
+	splay_node_t *leftbottom = &left, *rightbottom = &right, *child;
+	splay_node_t *node = tree->root;
+	int c;
+
+	while((c = tree->compare(data, node->data))) {
+		if(c < 0) {
+			child = node->left;
+
+			if(child) {
+				c = tree->compare(data, child->data);
+				
+				if(c < 0) {
+					rightbottom->left = child;
+					child->parent = rightbottom;
+					rightbottom = child;
+
+					node->left = child->right;
+					child->right = node;
+					node->parent = child;
+					node = child->left;
+					child->left = NULL;
+				} else if (c > 0) {
+					if(!child->right)
+						break;
+
+					leftbottom->right = child;
+					child->parent = leftbottom;
+					leftbottom = child;
+
+					rightbottom->left = node;
+					node->parent = rightbottom;
+					rightbottom = node;
+
+					node->left = NULL;
+					node = child->right;
+					child->right = NULL;
+				} else {
+					rightbottom->left = node;
+					node->parent = rightbottom;
+					rightbottom = node;
+
+					node->left = NULL;
+					child->parent = NULL;
+					node = child;
+					break;
+				}
+			} else {
+				break;
+			}
+		} else {
+			child = node->right;
+
+			if(child) {
+				c = tree->compare(data, child->data);
+				
+				if(c > 0) {
+					leftbottom->right = child;
+					child->parent = leftbottom;
+					leftbottom = child;
+
+					node->right = child->left;
+					child->left = node;
+					node->parent = child;
+					node = child->right;
+					child->right = NULL;
+				} else if (c < 0) {
+					if(!child->left)
+						break;
+
+					rightbottom->left = child;
+					child->parent = rightbottom;
+					rightbottom = child;
+
+					leftbottom->right = node;
+					node->parent = leftbottom;
+					leftbottom = node;
+
+					node->right = NULL;
+					node = child->left;
+					child->left = NULL;
+				} else {
+					leftbottom->right = node;
+					node->parent = leftbottom;
+					leftbottom = node;
+
+					node->right = NULL;
+					child->parent = NULL;
+					node = child;
+					break;
+				}
+			} else {
+				break;
+			}
+		}
+	}
+
+	tree->root = node;
+
+	/* Merge trees */
+
+	if(left.right) {
+		if(node->left) {
+			leftbottom->right = node->left;
+			node->left->parent = leftbottom;
+		}
+		node->left = left.right;
+		left.right->parent = node;
+	}
+
+	if(right.left) {
+		if(node->right) {
+			rightbottom->left = node->right;
+			node->right->parent = rightbottom;
+		}
+		node->right = right.left;
+		right.left->parent = node;
+	}
+
+	if(result)
+		*result = c;
+
+	return node;
+}
+				
+		
+static void splay_bottom_up(splay_tree_t *tree, splay_node_t *node) {
+	splay_node_t *parent, *grandparent;
+
+	while(node->parent) {
+		parent = node->parent;
+		grandparent = node->parent->parent;
+
+		if(!grandparent) { /* zig */
+			if(node == parent->left) {
+				parent->left = node->right;
+				node->right = parent;
+			} else {
+				parent->right = node->left;
+				node->left = parent;
+			}
+
+			parent->parent = node;
+			node->parent = NULL;
+		} else {
+			if(node == grandparent->left->left) { /* left zig-zig */
+				grandparent->left = parent->right;
+				parent->right = grandparent;
+				grandparent->parent = parent;
+
+				parent->left = node->right;
+				node->right = parent;
+				parent->parent = node;
+
+			} else if(node == grandparent->right->right) { /* right zig-zig */
+				grandparent->right = parent->left;
+				parent->left = grandparent;
+				grandparent->parent = parent;
+
+				parent->right = node->left;
+				node->left = parent;
+				parent->parent = node;
+
+			} else if(node == grandparent->left->right) { /* left-right zig-zag */
+				parent->right = node->left;
+				node->left = parent;
+				parent->parent = node;
+
+				grandparent->left = node->right;
+				node->right = grandparent;
+				grandparent->parent = node;
+
+			} else { /* right-left zig-zag */
+				parent->left = node->right;
+				node->right = parent;
+				parent->parent = node;
+
+				grandparent->right = node->left;
+				node->left = grandparent;
+				grandparent->parent = node;
+			}
+
+			node->parent = grandparent->parent;
+
+			if(node->parent) {
+				if(grandparent == node->parent->left)
+					node->parent->left = node;
+				else
+					node->parent->right = node;
+			}
+		}
+	}
+
+	tree->root = node;
+}
+
+/* (De)constructors */
+
+splay_tree_t *splay_alloc_tree(splay_compare_t compare, splay_action_t delete) {
+	splay_tree_t *tree;
+
+	tree = xmalloc_and_zero(sizeof(splay_tree_t));
+	tree->compare = compare;
+	tree->delete = delete;
+
+	return tree;
+}
+
+void splay_free_tree(splay_tree_t *tree) {
+	free(tree);
+}
+
+splay_node_t *splay_alloc_node(void) {
+	return xmalloc_and_zero(sizeof(splay_node_t));
+}
+
+void splay_free_node(splay_tree_t *tree, splay_node_t *node) {
+	if(node->data && tree->delete)
+		tree->delete(node->data);
+
+	free(node);
+}
+
+/* Searching */
+
+void *splay_search(splay_tree_t *tree, const void *data) {
+	splay_node_t *node;
+
+	node = splay_search_node(tree, data);
+
+	return node ? node->data : NULL;
+}
+
+void *splay_search_closest(splay_tree_t *tree, const void *data, int *result) {
+	splay_node_t *node;
+
+	node = splay_search_closest_node(tree, data, result);
+
+	return node ? node->data : NULL;
+}
+
+void *splay_search_closest_smaller(splay_tree_t *tree, const void *data) {
+	splay_node_t *node;
+
+	node = splay_search_closest_smaller_node(tree, data);
+
+	return node ? node->data : NULL;
+}
+
+void *splay_search_closest_greater(splay_tree_t *tree, const void *data) {
+	splay_node_t *node;
+
+	node = splay_search_closest_greater_node(tree, data);
+
+	return node ? node->data : NULL;
+}
+
+splay_node_t *splay_search_node(splay_tree_t *tree, const void *data) {
+	splay_node_t *node;
+	int result;
+
+	node = splay_search_closest_node(tree, data, &result);
+
+	return result ? NULL : node;
+}
+
+splay_node_t *splay_search_closest_node_nosplay(const splay_tree_t *tree, const void *data, int *result) {
+	splay_node_t *node;
+	int c;
+
+	node = tree->root;
+
+	if(!node) {
+		if(result)
+			*result = 0;
+		return NULL;
+	}
+
+	for(;;) {
+		c = tree->compare(data, node->data);
+
+		if(c < 0) {
+			if(node->left)
+				node = node->left;
+			else {
+				if(result)
+					*result = -1;
+				break;
+			}
+		} else if(c > 0) {
+			if(node->right)
+				node = node->right;
+			else {
+				if(result)
+					*result = 1;
+				break;
+			}
+		} else {
+			if(result)
+				*result = 0;
+			break;
+		}
+	}
+
+	return node;
+}
+
+splay_node_t *splay_search_closest_node(splay_tree_t *tree, const void *data, int *result) {
+	return splay_top_down(tree, data, result);
+}
+
+splay_node_t *splay_search_closest_smaller_node(splay_tree_t *tree, const void *data) {
+	splay_node_t *node;
+	int result;
+
+	node = splay_search_closest_node(tree, data, &result);
+
+	if(result < 0)
+		node = node->prev;
+
+	return node;
+}
+
+splay_node_t *splay_search_closest_greater_node(splay_tree_t *tree, const void *data) {
+	splay_node_t *node;
+	int result;
+
+	node = splay_search_closest_node(tree, data, &result);
+
+	if(result > 0)
+		node = node->next;
+
+	return node;
+}
+
+/* Insertion and deletion */
+
+splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
+	splay_node_t *closest, *new;
+	int result;
+
+	if(!tree->root) {
+		new = splay_alloc_node();
+		new->data = data;
+		splay_insert_top(tree, new);
+	} else {
+		closest = splay_search_closest_node_nosplay(tree, data, &result);
+
+		if(!result)
+			return NULL;
+
+		new = splay_alloc_node();
+		new->data = data;
+		
+		if(result < 0)
+			splay_insert_before(tree, closest, new);
+		else
+			splay_insert_after(tree, closest, new);
+	}			
+
+	return new;
+}
+
+splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
+	splay_node_t *closest;
+	int result;
+
+	if(!tree->root)
+		splay_insert_top(tree, node);
+	else {
+		closest = splay_search_closest_node_nosplay(tree, node->data, &result);
+		
+		if(!result)
+			return NULL;
+
+		if(result < 0)
+			splay_insert_before(tree, closest, node);
+		else
+			splay_insert_after(tree, closest, node);
+	}
+
+	return node;
+}
+
+void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
+	node->prev = node->next = node->parent = NULL;
+	tree->head = tree->tail = tree->root = node;
+}
+
+void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
+	if(!before) {
+		if(tree->tail)
+			splay_insert_after(tree, tree->tail, node);
+		else
+			splay_insert_top(tree, node);
+		return;
+	}
+
+	node->next = before;
+	node->parent = before;
+	node->prev = before->prev;
+
+	if(before->left) {
+		splay_insert_after(tree, before->prev, node);
+		return;
+	}
+
+	if(before->prev)
+		before->prev->next = node;
+	else
+		tree->head = node;
+
+	before->prev = node;
+	before->left = node;
+
+	splay_bottom_up(tree, node);
+}
+
+void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
+	if(!after) {
+		if(tree->head)
+			splay_insert_before(tree, tree->head, node);
+		else
+			splay_insert_top(tree, node);
+		return;
+	}
+
+	if(after->right) {
+		splay_insert_before(tree, after->next, node);
+		return;
+	}
+
+	node->prev = after;
+	node->parent = after;
+	node->next = after->next;
+
+	if(after->next)
+		after->next->prev = node;
+	else
+		tree->tail = node;
+
+	after->next = node;
+	after->right = node;
+
+	splay_bottom_up(tree, node);
+}
+
+splay_node_t *splay_unlink(splay_tree_t *tree, void *data) {
+	splay_node_t *node;
+	int result;
+
+	node = splay_search_closest_node_nosplay(tree, data, &result);
+
+	if(node && !result)
+		splay_unlink_node(tree, node);
+
+	return node;
+}
+
+void splay_unlink_node(splay_tree_t *tree, splay_node_t *node) {
+	if(node->prev)
+		node->prev->next = node->next;
+	else
+		tree->head = node->next;
+
+	if(node->next)
+		node->next->prev = node->prev;
+	else
+		tree->tail = node->prev;
+
+	if(node->left) {
+		node->left->parent = NULL;
+		tree->root = node->left;
+
+		if(node->right) {
+			splay_bottom_up(tree, node->prev);
+			node->prev->right = node->right;
+			node->right->parent = node->prev;
+		}
+	} else {
+		node->right->parent = NULL;
+		tree->root = node->right;
+	}
+}
+
+void splay_delete_node(splay_tree_t *tree, splay_node_t *node) {
+	splay_unlink_node(tree, node);
+	splay_free_node(tree, node);
+}
+
+void splay_delete(splay_tree_t *tree, void *data) {
+	splay_node_t *node;
+
+	node = splay_search_node(tree, data);
+
+	if(node)
+		splay_delete_node(tree, node);
+}
+
+/* Fast tree cleanup */
+
+void splay_delete_tree(splay_tree_t *tree) {
+	splay_node_t *node, *next;
+
+	for(node = tree->root; node; node = next) {
+		next = node->next;
+		splay_free_node(tree, node);
+	}
+
+	splay_free_tree(tree);
+}
+
+/* Tree walking */
+
+void splay_foreach(const splay_tree_t *tree, splay_action_t action) {
+	splay_node_t *node, *next;
+
+	for(node = tree->head; node; node = next) {
+		next = node->next;
+		action(node->data);
+	}
+}
+
+void splay_foreach_node(const splay_tree_t *tree, splay_action_t action) {
+	splay_node_t *node, *next;
+
+	for(node = tree->head; node; node = next) {
+		next = node->next;
+		action(node);
+	}
+}
diff --git a/lib/splay_tree.h b/lib/splay_tree.h
new file mode 100644
index 00000000..a638eca9
--- /dev/null
+++ b/lib/splay_tree.h
@@ -0,0 +1,109 @@
+/*
+    splay_tree.h -- header file for splay_tree.c
+    Copyright (C) 2004 Guus Sliepen <guus@tinc-vpn.org>
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    $Id: splay_tree.h 1374 2004-03-21 14:21:22Z guus $
+*/
+
+
+#ifndef __SPLAY_TREE_H__
+#define __SPLAY_TREE_H__
+
+typedef struct splay_node_t {
+
+	/* Linked list part */
+
+	struct splay_node_t *next;
+	struct splay_node_t *prev;
+
+	/* Tree part */
+
+	struct splay_node_t *parent;
+	struct splay_node_t *left;
+	struct splay_node_t *right;
+
+	/* Payload */
+
+	void *data;
+
+} splay_node_t;
+
+typedef int (*splay_compare_t)(const void *, const void *);
+typedef void (*splay_action_t)(const void *);
+typedef void (*splay_action_node_t)(const splay_node_t *);
+
+typedef struct splay_tree_t {
+
+	/* Linked list part */
+
+	splay_node_t *head;
+	splay_node_t *tail;
+
+	/* Tree part */
+
+	splay_node_t *root;
+
+	splay_compare_t compare;
+	splay_action_t delete;
+
+} splay_tree_t;
+
+/* (De)constructors */
+
+extern splay_tree_t *splay_alloc_tree(splay_compare_t, splay_action_t);
+extern void splay_free_tree(splay_tree_t *);
+
+extern splay_node_t *splay_alloc_node(void);
+extern void splay_free_node(splay_tree_t *tree, splay_node_t *);
+
+/* Insertion and deletion */
+
+extern splay_node_t *splay_insert(splay_tree_t *, void *);
+extern splay_node_t *splay_insert_node(splay_tree_t *, splay_node_t *);
+
+extern void splay_insert_top(splay_tree_t *, splay_node_t *);
+extern void splay_insert_before(splay_tree_t *, splay_node_t *, splay_node_t *);
+extern void splay_insert_after(splay_tree_t *, splay_node_t *, splay_node_t *);
+
+extern splay_node_t *splay_unlink(splay_tree_t *, void *);
+extern void splay_unlink_node(splay_tree_t *tree, splay_node_t *);
+extern void splay_delete(splay_tree_t *, void *);
+extern void splay_delete_node(splay_tree_t *, splay_node_t *);
+
+/* Fast tree cleanup */
+
+extern void splay_delete_tree(splay_tree_t *);
+
+/* Searching */
+
+extern void *splay_search(splay_tree_t *, const void *);
+extern void *splay_search_closest(splay_tree_t *, const void *, int *);
+extern void *splay_search_closest_smaller(splay_tree_t *, const void *);
+extern void *splay_search_closest_greater(splay_tree_t *, const void *);
+
+extern splay_node_t *splay_search_node(splay_tree_t *, const void *);
+extern splay_node_t *splay_search_closest_node(splay_tree_t *, const void *, int *);
+extern splay_node_t *splay_search_closest_node_nosplay(const splay_tree_t *, const void *, int *);
+extern splay_node_t *splay_search_closest_smaller_node(splay_tree_t *, const void *);
+extern splay_node_t *splay_search_closest_greater_node(splay_tree_t *, const void *);
+
+/* Tree walking */
+
+extern void splay_foreach(const splay_tree_t *, splay_action_t);
+extern void splay_foreach_node(const splay_tree_t *, splay_action_t);
+
+#endif