1 #ifndef ubi_SplayTree_H
2 #define ubi_SplayTree_H
3 /* ========================================================================== **
6 * Copyright (C) 1993,1995 by Christopher R. Hertel
8 * Email: crh@ubiqx.mn.org
9 * -------------------------------------------------------------------------- **
11 * This module implements "splay" trees. Splay trees are binary trees
12 * that are rearranged (splayed) whenever a node is accessed. The
13 * splaying process *tends* to make the tree bushier (improves balance),
14 * and the nodes that are accessed most frequently *tend* to be closer to
17 * References: "Self-Adjusting Binary Search Trees", by Daniel Sleator and
18 * Robert Tarjan. Journal of the Association for Computing
19 * Machinery Vol 32, No. 3, July 1985 pp. 652-686
21 * -------------------------------------------------------------------------- **
23 * This library is free software; you can redistribute it and/or
24 * modify it under the terms of the GNU Library General Public
25 * License as published by the Free Software Foundation; either
26 * version 2 of the License, or (at your option) any later version.
28 * This library is distributed in the hope that it will be useful,
29 * but WITHOUT ANY WARRANTY; without even the implied warranty of
30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
31 * Library General Public License for more details.
33 * You should have received a copy of the GNU Library General Public
34 * License along with this library; if not, write to the Free
35 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
37 * -------------------------------------------------------------------------- **
39 * Log: ubi_SplayTree.h,v
40 * Revision 3.0 1997/12/08 05:32:35 crh
41 * This is a new major revision level because of a redesign of the handling
42 * of the pointers in the ubi_trNode structure. See ubi_BinTree for more
45 * Revision 2; 1995/02/27 - 1997/12/07:
46 * Major changes: added the function ubi_sptSplay().
48 * Revision 1; 93/10/15 - 95/02/27:
49 * Added the ubi_tr defines. See ubi_BinTree.h for more info.
51 * Revision 0.0 93/04/21 23:07:13 CRH
52 * Initial version, written by Christopher R. Hertel.
53 * This module implements Splay Trees using the ubi_BinTree module as a basis.
55 * ========================================================================== **
58 #include "ubi_BinTree.h" /* Base binary tree functions, types, etc. */
60 /* ========================================================================== **
61 * Function prototypes...
64 ubi_trBool ubi_sptInsert( ubi_btRootPtr RootPtr,
65 ubi_btNodePtr NewNode,
66 ubi_btItemPtr ItemPtr,
67 ubi_btNodePtr *OldNode );
68 /* ------------------------------------------------------------------------ **
69 * This function uses a non-recursive algorithm to add a new element to the
72 * Input: RootPtr - a pointer to the ubi_btRoot structure that indicates
73 * the root of the tree to which NewNode is to be added.
74 * NewNode - a pointer to an ubi_btNode structure that is NOT
76 * ItemPtr - A pointer to the sort key that is stored within
77 * *NewNode. ItemPtr MUST point to information stored
78 * in *NewNode or an EXACT DUPLICATE. The key data
79 * indicated by ItemPtr is used to place the new node
81 * OldNode - a pointer to an ubi_btNodePtr. When searching
82 * the tree, a duplicate node may be found. If
83 * duplicates are allowed, then the new node will
84 * be simply placed into the tree. If duplicates
85 * are not allowed, however, then one of two things
87 * 1) if overwritting *is not* allowed, this
88 * function will return FALSE (indicating that
89 * the new node could not be inserted), and
90 * *OldNode will point to the duplicate that is
92 * 2) if overwritting *is* allowed, then this
93 * function will swap **OldNode for *NewNode.
94 * In this case, *OldNode will point to the node
95 * that was removed (thus allowing you to free
97 * ** If you are using overwrite mode, ALWAYS **
98 * ** check the return value of this parameter! **
99 * Note: You may pass NULL in this parameter, the
100 * function knows how to cope. If you do this,
101 * however, there will be no way to return a
102 * pointer to an old (ie. replaced) node (which is
103 * a problem if you are using overwrite mode).
105 * Output: a boolean value indicating success or failure. The function
106 * will return FALSE if the node could not be added to the tree.
107 * Such failure will only occur if duplicates are not allowed,
108 * nodes cannot be overwritten, AND a duplicate key was found
110 * ------------------------------------------------------------------------ **
113 ubi_btNodePtr ubi_sptRemove( ubi_btRootPtr RootPtr, ubi_btNodePtr DeadNode );
114 /* ------------------------------------------------------------------------ **
115 * This function removes the indicated node from the tree.
117 * Input: RootPtr - A pointer to the header of the tree that contains
118 * the node to be removed.
119 * DeadNode - A pointer to the node that will be removed.
121 * Output: This function returns a pointer to the node that was removed
122 * from the tree (ie. the same as DeadNode).
124 * Note: The node MUST be in the tree indicated by RootPtr. If not,
125 * strange and evil things will happen to your trees.
126 * ------------------------------------------------------------------------ **
129 ubi_btNodePtr ubi_sptLocate( ubi_btRootPtr RootPtr,
130 ubi_btItemPtr FindMe,
131 ubi_trCompOps CompOp );
132 /* ------------------------------------------------------------------------ **
133 * The purpose of ubi_btLocate() is to find a node or set of nodes given
134 * a target value and a "comparison operator". The Locate() function is
135 * more flexible and (in the case of trees that may contain dupicate keys)
136 * more precise than the ubi_btFind() function. The latter is faster,
137 * but it only searches for exact matches and, if the tree contains
138 * duplicates, Find() may return a pointer to any one of the duplicate-
142 * RootPtr - A pointer to the header of the tree to be searched.
143 * FindMe - An ubi_btItemPtr that indicates the key for which to
145 * CompOp - One of the following:
146 * CompOp Return a pointer to the node with
147 * ------ ---------------------------------
148 * ubi_trLT - the last key value that is less
150 * ubi_trLE - the first key matching FindMe, or
151 * the last key that is less than
153 * ubi_trEQ - the first key matching FindMe.
154 * ubi_trGE - the first key matching FindMe, or the
155 * first key greater than FindMe.
156 * ubi_trGT - the first key greater than FindMe.
158 * A pointer to the node matching the criteria listed above under
159 * CompOp, or NULL if no node matched the criteria.
162 * In the case of trees with duplicate keys, Locate() will behave as
166 * Keys: 1 2 2 2 3 3 3 3 3 4 4 Keys: 1 1 2 2 2 4 4 5 5 5 6
170 * That is, when returning a pointer to a node with a key that is LESS
171 * THAN the target key (FindMe), Locate() will return a pointer to the
172 * LAST matching node.
173 * When returning a pointer to a node with a key that is GREATER
174 * THAN the target key (FindMe), Locate() will return a pointer to the
175 * FIRST matching node.
177 * See Also: ubi_btFind(), ubi_btFirstOf(), ubi_btLastOf().
178 * ------------------------------------------------------------------------ **
181 ubi_btNodePtr ubi_sptFind( ubi_btRootPtr RootPtr,
182 ubi_btItemPtr FindMe );
183 /* ------------------------------------------------------------------------ **
184 * This function performs a non-recursive search of a tree for any node
185 * matching a specific key.
188 * RootPtr - a pointer to the header of the tree to be searched.
189 * FindMe - a pointer to the key value for which to search.
192 * A pointer to a node with a key that matches the key indicated by
193 * FindMe, or NULL if no such node was found.
195 * Note: In a tree that allows duplicates, the pointer returned *might
196 * not* point to the (sequentially) first occurance of the
197 * desired key. In such a tree, it may be more useful to use
199 * ------------------------------------------------------------------------ **
202 void ubi_sptSplay( ubi_btRootPtr RootPtr,
203 ubi_btNodePtr SplayMe );
204 /* ------------------------------------------------------------------------ **
205 * This function allows you to splay the tree at a given node, thus moving
206 * the node to the top of the tree.
209 * RootPtr - a pointer to the header of the tree to be splayed.
210 * SplayMe - a pointer to a node within the tree. This will become
214 * Notes: This is an uncharacteristic function for this group of modules
215 * in that it provides access to the internal balancing routines,
216 * which would normally be hidden.
217 * Splaying the tree will not damage it (assuming that I've done
218 * *my* job), but there is overhead involved. I don't recommend
219 * that you use this function unless you understand the underlying
221 * ------------------------------------------------------------------------ **
224 int ubi_sptModuleID( int size, char *list[] );
225 /* ------------------------------------------------------------------------ **
226 * Returns a set of strings that identify the module.
228 * Input: size - The number of elements in the array <list>.
229 * list - An array of pointers of type (char *). This array
230 * should, initially, be empty. This function will fill
231 * in the array with pointers to strings.
232 * Output: The number of elements of <list> that were used. If this value
233 * is less than <size>, the values of the remaining elements are
236 * Notes: Please keep in mind that the pointers returned indicate strings
237 * stored in static memory. Don't free() them, don't write over
238 * them, etc. Just read them.
239 * ------------------------------------------------------------------------ **
242 /* -------------------------------------------------------------------------- **
245 * This set of defines allows you to write programs that will use any of the
246 * implemented binary tree modules (currently BinTree, AVLtree, and SplayTree).
247 * Instead of using ubi_bt..., use ubi_tr..., and select the tree type by
248 * including the appropriate module header.
255 #undef ubi_trModuleID
257 #define ubi_trInsert( Rp, Nn, Ip, On ) \
258 ubi_sptInsert( (ubi_btRootPtr)(Rp), (ubi_btNodePtr)(Nn), \
259 (ubi_btItemPtr)(Ip), (ubi_btNodePtr *)(On) )
261 #define ubi_trRemove( Rp, Dn ) \
262 ubi_sptRemove( (ubi_btRootPtr)(Rp), (ubi_btNodePtr)(Dn) )
264 #define ubi_trLocate( Rp, Ip, Op ) \
265 ubi_sptLocate( (ubi_btRootPtr)(Rp), \
266 (ubi_btItemPtr)(Ip), \
267 (ubi_trCompOps)(Op) )
269 #define ubi_trFind( Rp, Ip ) \
270 ubi_sptFind( (ubi_btRootPtr)(Rp), (ubi_btItemPtr)(Ip) )
272 #define ubi_trModuleID( s, l ) ubi_sptModuleID( s, l )
274 /* ================================ The End ================================= */
275 #endif /* ubi_SplayTree_H */