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+#ifndef ubi_BinTree_H
+#define ubi_BinTree_H
+/* ========================================================================== **
+ * ubi_BinTree.h
+ *
+ * Copyright (C) 1991-1997 by Christopher R. Hertel
+ *
+ * Email: crh@ubiqx.mn.org
+ * -------------------------------------------------------------------------- **
+ *
+ * ubi_BinTree manages a simple binary tree. Nothing fancy here. No height
+ * balancing, no restructuring. Still, a good tool for creating short, low-
+ * overhead sorted lists of things that need to be found in a hurry.
+ *
+ * In addition, this module provides a good basis for creating other types
+ * of binary tree handling modules.
+ *
+ * -------------------------------------------------------------------------- **
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * -------------------------------------------------------------------------- **
+ *
+ * Revision 2.4 1997/07/26 04:11:14 crh
+ * + Just to be annoying I changed ubi_TRUE and ubi_FALSE to ubi_trTRUE
+ * and ubi_trFALSE.
+ * + There is now a type ubi_trBool to go with ubi_trTRUE and ubi_trFALSE.
+ * + There used to be something called "ubi_TypeDefs.h". I got rid of it.
+ * + Added function ubi_btLeafNode().
+ *
+ * Revision 2.3 1997/06/03 05:15:27 crh
+ * Changed TRUE and FALSE to ubi_TRUE and ubi_FALSE to avoid conflicts.
+ * Also changed the interface to function InitTree(). See the comments
+ * for this function for more information.
+ *
+ * Revision 2.2 1995/10/03 22:00:40 CRH
+ * Ubisized!
+ *
+ * Revision 2.1 95/03/09 23:43:46 CRH
+ * Added the ModuleID static string and function. These modules are now
+ * self-identifying.
+ *
+ * Revision 2.0 95/02/27 22:00:33 CRH
+ * Revision 2.0 of this program includes the following changes:
+ *
+ * 1) A fix to a major typo in the RepaceNode() function.
+ * 2) The addition of the static function Border().
+ * 3) The addition of the public functions FirstOf() and LastOf(), which
+ * use Border(). These functions are used with trees that allow
+ * duplicate keys.
+ * 4) A complete rewrite of the Locate() function. Locate() now accepts
+ * a "comparison" operator.
+ * 5) Overall enhancements to both code and comments.
+ *
+ * I decided to give this a new major rev number because the interface has
+ * changed. In particular, there are two new functions, and changes to the
+ * Locate() function.
+ *
+ * Revision 1.0 93/10/15 22:55:04 CRH
+ * With this revision, I have added a set of #define's that provide a single,
+ * standard API to all existing tree modules. Until now, each of the three
+ * existing modules had a different function and typedef prefix, as follows:
+ *
+ * Module Prefix
+ * ubi_BinTree ubi_bt
+ * ubi_AVLtree ubi_avl
+ * ubi_SplayTree ubi_spt
+ *
+ * To further complicate matters, only those portions of the base module
+ * (ubi_BinTree) that were superceeded in the new module had the new names.
+ * For example, if you were using ubi_AVLtree, the AVL node structure was
+ * named "ubi_avlNode", but the root structure was still "ubi_btRoot". Using
+ * SplayTree, the locate function was called "ubi_sptLocate", but the next
+ * and previous functions remained "ubi_btNext" and "ubi_btPrev".
+ *
+ * This was not too terrible if you were familiar with the modules and knew
+ * exactly which tree model you wanted to use. If you wanted to be able to
+ * change modules (for speed comparisons, etc), things could get messy very
+ * quickly.
+ *
+ * So, I have added a set of defined names that get redefined in any of the
+ * descendant modules. To use this standardized interface in your code,
+ * simply replace all occurances of "ubi_bt", "ubi_avl", and "ubi_spt" with
+ * "ubi_tr". The "ubi_tr" names will resolve to the correct function or
+ * datatype names for the module that you are using. Just remember to
+ * include the header for that module in your program file. Because these
+ * names are handled by the preprocessor, there is no added run-time
+ * overhead.
+ *
+ * Note that the original names do still exist, and can be used if you wish
+ * to write code directly to a specific module. This should probably only be
+ * done if you are planning to implement a new descendant type, such as
+ * red/black trees. CRH
+ *
+ * V0.0 - June, 1991 - Written by Christopher R. Hertel (CRH).
+ *
+ * ========================================================================== **
+ */
+
+/* -------------------------------------------------------------------------- **
+ * Macros and constants.
+ *
+ * General purpose:
+ * ubi_trTRUE - Boolean TRUE.
+ * ubi_trFALSE - Boolean FALSE.
+ *
+ * Flags used in the tree header:
+ * ubi_trOVERWRITE - This flag indicates that an existing node may be
+ * overwritten by a new node with a matching key.
+ * ubi_trDUPKEY - This flag indicates that the tree allows duplicate
+ * keys. If the tree does allow duplicates, the
+ * overwrite flag is ignored.
+ *
+ * Node link array index constants: (Each node has an array of three
+ * pointers. One to the left, one to the right, and one back to the
+ * parent.)
+ * LEFT - Left child pointer.
+ * PARENT - Parent pointer.
+ * RIGHT - Right child pointer.
+ * EQUAL - Synonym for PARENT.
+ *
+ * ubi_trCompOps: These values are used in the ubi_trLocate() function.
+ * ubi_trLT - request the first instance of the greatest key less than
+ * the search key.
+ * ubi_trLE - request the first instance of the greatest key that is less
+ * than or equal to the search key.
+ * ubi_trEQ - request the first instance of key that is equal to the
+ * search key.
+ * ubi_trGE - request the first instance of a key that is greater than
+ * or equal to the search key.
+ * ubi_trGT - request the first instance of the first key that is greater
+ * than the search key.
+ * -------------------------------------------------------------------------- **
+ */
+
+#define ubi_trTRUE 0xFF
+#define ubi_trFALSE 0x00
+
+#define ubi_trOVERWRITE 0x01 /* Turn on allow overwrite */
+#define ubi_trDUPKEY 0x02 /* Turn on allow duplicate keys */
+
+/* Pointer array index constants... */
+#define LEFT 0x00
+#define PARENT 0x01
+#define RIGHT 0x02
+#define EQUAL PARENT
+
+typedef enum {
+ ubi_trLT = 1,
+ ubi_trLE,
+ ubi_trEQ,
+ ubi_trGE,
+ ubi_trGT
+ } ubi_trCompOps;
+
+/* -------------------------------------------------------------------------- **
+ * These three macros allow simple manipulation of pointer index values (LEFT,
+ * RIGHT, and PARENT).
+ *
+ * Normalize() - converts {LEFT, PARENT, RIGHT} into {-1, 0 ,1}. C
+ * uses {negative, zero, positive} values to indicate
+ * {less than, equal to, greater than}.
+ * AbNormal() - converts {negative, zero, positive} to {LEFT, PARENT,
+ * RIGHT} (opposite of Normalize()). Note: C comparison
+ * functions, such as strcmp(), return {negative, zero,
+ * positive} values, which are not necessarily {-1, 0,
+ * 1}. This macro uses the the ubi_btSgn() function to
+ * compensate.
+ * RevWay() - converts LEFT to RIGHT and RIGHT to LEFT. PARENT (EQUAL)
+ * is left as is.
+ * -------------------------------------------------------------------------- **
+ */
+#define Normalize(W) ((char)((W)-EQUAL))
+#define AbNormal(W) ((char)( EQUAL+((char)ubi_btSgn( (W) )) ))
+#define RevWay(W) ((char)((W)==LEFT?RIGHT:((W)==RIGHT?LEFT:EQUAL)))
+
+/* -------------------------------------------------------------------------- **
+ * These macros allow us to quickly read the values of the OVERWRITE and
+ * DUPlicate KEY bits of the tree root flags field.
+ * -------------------------------------------------------------------------- **
+ */
+#define Dups_OK(A) ((ubi_trDUPKEY & ((A)->flags))?(ubi_trTRUE):(ubi_trFALSE))
+#define Ovwt_OK(A) ((ubi_trOVERWRITE & ((A)->flags))?(ubi_trTRUE):(ubi_trFALSE))
+
+/* -------------------------------------------------------------------------- **
+ * Typedefs...
+ *
+ * ubi_trBool - Your typcial true or false...
+ *
+ * Item Pointer: The ubi_btItemPtr is a generic pointer. It is used to
+ * indicate a key that is being searched for within the tree.
+ * Searching occurs whenever the ubi_trFind(), ubi_trLocate(),
+ * or ubi_trInsert() functions are called.
+ * -------------------------------------------------------------------------- **
+ */
+
+typedef unsigned char ubi_trBool;
+
+typedef void *ubi_btItemPtr; /* A pointer to data within a node. */
+
+/* ------------------------------------------------------------------------- **
+ * Binary Tree Node Structure: This structure defines the basic elements of
+ * the tree nodes. In general you *SHOULD NOT PLAY WITH THESE FIELDS*!
+ * But, of course, I have to put the structure into this header so that
+ * you can use it as a building block.
+ *
+ * The fields are as follows:
+ * Link - an array of pointers. These pointers are manipulated by
+ * the BT routines. The pointers indicate the left and right
+ * child nodes and the parent node. By keeping track of the
+ * parent pointer, we avoid the need for recursive routines or
+ * hand-tooled stacks to keep track of our path back to the
+ * root. The use of these pointers is subject to change without
+ * notice.
+ * gender - a one-byte field indicating whether the node is the RIGHT or
+ * LEFT child of its parent. If the node is the root of the
+ * tree, gender will be PARENT.
+ * ------------------------------------------------------------------------- **
+ */
+typedef struct ubi_btNodeStruct {
+ struct ubi_btNodeStruct *Link[ 3 ];
+ char gender;
+ } ubi_btNode;
+
+typedef ubi_btNode *ubi_btNodePtr; /* Pointer to an ubi_btNode structure. */
+
+/* ------------------------------------------------------------------------- **
+ * The next three typedefs define standard function types used by the binary
+ * tree management routines. In particular:
+ *
+ * ubi_btCompFunc is a pointer to a comparison function. Comparison
+ * functions are passed an ubi_btItemPtr and an
+ * ubi_btNodePtr. They return a value that is (<0), 0,
+ * or (>0) to indicate that the Item is (respectively)
+ * "less than", "equal to", or "greater than" the Item
+ * contained within the node. (See ubi_btInitTree()).
+ * ubi_btActionRtn is a pointer to a function that may be called for each
+ * node visited when performing a tree traversal (see
+ * ubi_btTraverse()). The function will be passed two
+ * parameters: the first is a pointer to a node in the
+ * tree, the second is a generic pointer that may point to
+ * anything that you like.
+ * ubi_btKillNodeRtn is a pointer to a function that will deallocate the
+ * memory used by a node (see ubi_btKillTree()). Since
+ * memory management is left up to you, deallocation may
+ * mean anything that you want it to mean. Just remember
+ * that the tree *will* be destroyed and that none of the
+ * node pointers will be valid any more.
+ * ------------------------------------------------------------------------- **
+ */
+
+typedef int (*ubi_btCompFunc)( ubi_btItemPtr, ubi_btNodePtr );
+
+typedef void (*ubi_btActionRtn)( ubi_btNodePtr, void * );
+
+typedef void (*ubi_btKillNodeRtn)( ubi_btNodePtr );
+
+/* -------------------------------------------------------------------------- **
+ * Tree Root Structure: This structure gives us a convenient handle for
+ * accessing whole AVL trees. The fields are:
+ * root - A pointer to the root node of the AVL tree.
+ * count - A count of the number of nodes stored in the tree.
+ * cmp - A pointer to the comparison routine to be used when building or
+ * searching the tree.
+ * flags - A set of bit flags. Two flags are currently defined:
+ *
+ * ubi_trOVERWRITE - If set, this flag indicates that a new node should
+ * (bit 0x01) overwrite an old node if the two have identical
+ * keys (ie., the keys are equal).
+ * ubi_trDUPKEY - If set, this flag indicates that the tree is
+ * (bit 0x02) allowed to contain nodes with duplicate keys.
+ *
+ * NOTE: ubi_trInsert() tests ubi_trDUPKEY before ubi_trOVERWRITE.
+ *
+ * All of these values are set when you initialize the root structure by
+ * calling ubi_trInitTree().
+ * -------------------------------------------------------------------------- **
+ */
+
+typedef struct {
+ ubi_btNodePtr root; /* A pointer to the root node of the tree */
+ unsigned long count; /* A count of the number of nodes in the tree */
+ ubi_btCompFunc cmp; /* A pointer to the tree's comparison function */
+ unsigned char flags; /* Overwrite Y|N, Duplicate keys Y|N... */
+ } ubi_btRoot;
+
+typedef ubi_btRoot *ubi_btRootPtr; /* Pointer to an ubi_btRoot structure. */
+
+
+/* -------------------------------------------------------------------------- **
+ * Function Prototypes.
+ */
+
+long ubi_btSgn( long x );
+ /* ------------------------------------------------------------------------ **
+ * Return the sign of x; {negative,zero,positive} ==> {-1, 0, 1}.
+ *
+ * Input: x - a signed long integer value.
+ *
+ * Output: the "sign" of x, represented as follows:
+ * -1 == negative
+ * 0 == zero (no sign)
+ * 1 == positive
+ *
+ * Note: This utility is provided in order to facilitate the conversion
+ * of C comparison function return values into BinTree direction
+ * values: {LEFT, PARENT, EQUAL}. It is INCORPORATED into the
+ * AbNormal() conversion macro!
+ *
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btInitNode( ubi_btNodePtr NodePtr );
+ /* ------------------------------------------------------------------------ **
+ * Initialize a tree node.
+ *
+ * Input: a pointer to a ubi_btNode structure to be initialized.
+ * Output: a pointer to the initialized ubi_btNode structure (ie. the
+ * same as the input pointer).
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btRootPtr ubi_btInitTree( ubi_btRootPtr RootPtr,
+ ubi_btCompFunc CompFunc,
+ unsigned char Flags );
+ /* ------------------------------------------------------------------------ **
+ * Initialize the fields of a Tree Root header structure.
+ *
+ * Input: RootPtr - a pointer to an ubi_btRoot structure to be
+ * initialized.
+ * CompFunc - a pointer to a comparison function that will be used
+ * whenever nodes in the tree must be compared against
+ * outside values.
+ * Flags - One bytes worth of flags. Flags include
+ * ubi_trOVERWRITE and ubi_trDUPKEY. See the header
+ * file for more info.
+ *
+ * Output: a pointer to the initialized ubi_btRoot structure (ie. the
+ * same value as RootPtr).
+ *
+ * Note: The interface to this function has changed from that of
+ * previous versions. The <Flags> parameter replaces two
+ * boolean parameters that had the same basic effect.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_trBool ubi_btInsert( ubi_btRootPtr RootPtr,
+ ubi_btNodePtr NewNode,
+ ubi_btItemPtr ItemPtr,
+ ubi_btNodePtr *OldNode );
+ /* ------------------------------------------------------------------------ **
+ * This function uses a non-recursive algorithm to add a new element to the
+ * tree.
+ *
+ * Input: RootPtr - a pointer to the ubi_btRoot structure that indicates
+ * the root of the tree to which NewNode is to be added.
+ * NewNode - a pointer to an ubi_btNode structure that is NOT
+ * part of any tree.
+ * ItemPtr - A pointer to the sort key that is stored within
+ * *NewNode. ItemPtr MUST point to information stored
+ * in *NewNode or an EXACT DUPLICATE. The key data
+ * indicated by ItemPtr is used to place the new node
+ * into the tree.
+ * OldNode - a pointer to an ubi_btNodePtr. When searching
+ * the tree, a duplicate node may be found. If
+ * duplicates are allowed, then the new node will
+ * be simply placed into the tree. If duplicates
+ * are not allowed, however, then one of two things
+ * may happen.
+ * 1) if overwritting *is not* allowed, this
+ * function will return FALSE (indicating that
+ * the new node could not be inserted), and
+ * *OldNode will point to the duplicate that is
+ * still in the tree.
+ * 2) if overwritting *is* allowed, then this
+ * function will swap **OldNode for *NewNode.
+ * In this case, *OldNode will point to the node
+ * that was removed (thus allowing you to free
+ * the node).
+ * ** If you are using overwrite mode, ALWAYS **
+ * ** check the return value of this parameter! **
+ * Note: You may pass NULL in this parameter, the
+ * function knows how to cope. If you do this,
+ * however, there will be no way to return a
+ * pointer to an old (ie. replaced) node (which is
+ * a problem if you are using overwrite mode).
+ *
+ * Output: a boolean value indicating success or failure. The function
+ * will return FALSE if the node could not be added to the tree.
+ * Such failure will only occur if duplicates are not allowed,
+ * nodes cannot be overwritten, AND a duplicate key was found
+ * within the tree.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btRemove( ubi_btRootPtr RootPtr,
+ ubi_btNodePtr DeadNode );
+ /* ------------------------------------------------------------------------ **
+ * This function removes the indicated node from the tree.
+ *
+ * Input: RootPtr - A pointer to the header of the tree that contains
+ * the node to be removed.
+ * DeadNode - A pointer to the node that will be removed.
+ *
+ * Output: This function returns a pointer to the node that was removed
+ * from the tree (ie. the same as DeadNode).
+ *
+ * Note: The node MUST be in the tree indicated by RootPtr. If not,
+ * strange and evil things will happen to your trees.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btLocate( ubi_btRootPtr RootPtr,
+ ubi_btItemPtr FindMe,
+ ubi_trCompOps CompOp );
+ /* ------------------------------------------------------------------------ **
+ * The purpose of ubi_btLocate() is to find a node or set of nodes given
+ * a target value and a "comparison operator". The Locate() function is
+ * more flexible and (in the case of trees that may contain dupicate keys)
+ * more precise than the ubi_btFind() function. The latter is faster,
+ * but it only searches for exact matches and, if the tree contains
+ * duplicates, Find() may return a pointer to any one of the duplicate-
+ * keyed records.
+ *
+ * Input:
+ * RootPtr - A pointer to the header of the tree to be searched.
+ * FindMe - An ubi_btItemPtr that indicates the key for which to
+ * search.
+ * CompOp - One of the following:
+ * CompOp Return a pointer to the node with
+ * ------ ---------------------------------
+ * ubi_trLT - the last key value that is less
+ * than FindMe.
+ * ubi_trLE - the first key matching FindMe, or
+ * the last key that is less than
+ * FindMe.
+ * ubi_trEQ - the first key matching FindMe.
+ * ubi_trGE - the first key matching FindMe, or the
+ * first key greater than FindMe.
+ * ubi_trGT - the first key greater than FindMe.
+ * Output:
+ * A pointer to the node matching the criteria listed above under
+ * CompOp, or NULL if no node matched the criteria.
+ *
+ * Notes:
+ * In the case of trees with duplicate keys, Locate() will behave as
+ * follows:
+ *
+ * Find: 3 Find: 3
+ * Keys: 1 2 2 2 3 3 3 3 3 4 4 Keys: 1 1 2 2 2 4 4 5 5 5 6
+ * ^ ^ ^ ^ ^
+ * LT EQ GT LE GE
+ *
+ * That is, when returning a pointer to a node with a key that is LESS
+ * THAN the target key (FindMe), Locate() will return a pointer to the
+ * LAST matching node.
+ * When returning a pointer to a node with a key that is GREATER
+ * THAN the target key (FindMe), Locate() will return a pointer to the
+ * FIRST matching node.
+ *
+ * See Also: ubi_btFind(), ubi_btFirstOf(), ubi_btLastOf().
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btFind( ubi_btRootPtr RootPtr,
+ ubi_btItemPtr FindMe );
+ /* ------------------------------------------------------------------------ **
+ * This function performs a non-recursive search of a tree for any node
+ * matching a specific key.
+ *
+ * Input:
+ * RootPtr - a pointer to the header of the tree to be searched.
+ * FindMe - a pointer to the key value for which to search.
+ *
+ * Output:
+ * A pointer to a node with a key that matches the key indicated by
+ * FindMe, or NULL if no such node was found.
+ *
+ * Note: In a tree that allows duplicates, the pointer returned *might
+ * not* point to the (sequentially) first occurance of the
+ * desired key. In such a tree, it may be more useful to use
+ * ubi_btLocate().
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btNext( ubi_btNodePtr P );
+ /* ------------------------------------------------------------------------ **
+ * Given the node indicated by P, find the (sorted order) Next node in the
+ * tree.
+ * Input: P - a pointer to a node that exists in a binary tree.
+ * Output: A pointer to the "next" node in the tree, or NULL if P pointed
+ * to the "last" node in the tree or was NULL.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btPrev( ubi_btNodePtr P );
+ /* ------------------------------------------------------------------------ **
+ * Given the node indicated by P, find the (sorted order) Previous node in
+ * the tree.
+ * Input: P - a pointer to a node that exists in a binary tree.
+ * Output: A pointer to the "previous" node in the tree, or NULL if P
+ * pointed to the "first" node in the tree or was NULL.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btFirst( ubi_btNodePtr P );
+ /* ------------------------------------------------------------------------ **
+ * Given the node indicated by P, find the (sorted order) First node in the
+ * subtree of which *P is the root.
+ * Input: P - a pointer to a node that exists in a binary tree.
+ * Output: A pointer to the "first" node in a subtree that has *P as its
+ * root. This function will return NULL only if P is NULL.
+ * Note: In general, you will be passing in the value of the root field
+ * of an ubi_btRoot structure.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btLast( ubi_btNodePtr P );
+ /* ------------------------------------------------------------------------ **
+ * Given the node indicated by P, find the (sorted order) Last node in the
+ * subtree of which *P is the root.
+ * Input: P - a pointer to a node that exists in a binary tree.
+ * Output: A pointer to the "last" node in a subtree that has *P as its
+ * root. This function will return NULL only if P is NULL.
+ * Note: In general, you will be passing in the value of the root field
+ * of an ubi_btRoot structure.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btFirstOf( ubi_btRootPtr RootPtr,
+ ubi_btItemPtr MatchMe,
+ ubi_btNodePtr p );
+ /* ------------------------------------------------------------------------ **
+ * Given a tree that a allows duplicate keys, and a pointer to a node in
+ * the tree, this function will return a pointer to the first (traversal
+ * order) node with the same key value.
+ *
+ * Input: RootPtr - A pointer to the root of the tree.
+ * MatchMe - A pointer to the key value. This should probably
+ * point to the key within node *p.
+ * p - A pointer to a node in the tree.
+ * Output: A pointer to the first node in the set of nodes with keys
+ * matching <FindMe>.
+ * Notes: Node *p MUST be in the set of nodes with keys matching
+ * <FindMe>. If not, this function will return NULL.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btLastOf( ubi_btRootPtr RootPtr,
+ ubi_btItemPtr MatchMe,
+ ubi_btNodePtr p );
+ /* ------------------------------------------------------------------------ **
+ * Given a tree that a allows duplicate keys, and a pointer to a node in
+ * the tree, this function will return a pointer to the last (traversal
+ * order) node with the same key value.
+ *
+ * Input: RootPtr - A pointer to the root of the tree.
+ * MatchMe - A pointer to the key value. This should probably
+ * point to the key within node *p.
+ * p - A pointer to a node in the tree.
+ * Output: A pointer to the last node in the set of nodes with keys
+ * matching <FindMe>.
+ * Notes: Node *p MUST be in the set of nodes with keys matching
+ * <FindMe>. If not, this function will return NULL.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_trBool ubi_btTraverse( ubi_btRootPtr RootPtr,
+ ubi_btActionRtn EachNode,
+ void *UserData );
+ /* ------------------------------------------------------------------------ **
+ * Traverse a tree in sorted order (non-recursively). At each node, call
+ * (*EachNode)(), passing a pointer to the current node, and UserData as the
+ * second parameter.
+ * Input: RootPtr - a pointer to an ubi_btRoot structure that indicates
+ * the tree to be traversed.
+ * EachNode - a pointer to a function to be called at each node
+ * as the node is visited.
+ * UserData - a generic pointer that may point to anything that
+ * you choose.
+ * Output: A boolean value. FALSE if the tree is empty, otherwise TRUE.
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_trBool ubi_btKillTree( ubi_btRootPtr RootPtr,
+ ubi_btKillNodeRtn FreeNode );
+ /* ------------------------------------------------------------------------ **
+ * Delete an entire tree (non-recursively) and reinitialize the ubi_btRoot
+ * structure. Note that this function will return FALSE if either parameter
+ * is NULL.
+ *
+ * Input: RootPtr - a pointer to an ubi_btRoot structure that indicates
+ * the root of the tree to delete.
+ * FreeNode - a function that will be called for each node in the
+ * tree to deallocate the memory used by the node.
+ *
+ * Output: A boolean value. FALSE if either input parameter was NULL, else
+ * TRUE.
+ *
+ * ------------------------------------------------------------------------ **
+ */
+
+ubi_btNodePtr ubi_btLeafNode( ubi_btNodePtr leader );
+ /* ------------------------------------------------------------------------ **
+ * Returns a pointer to a leaf node.
+ *
+ * Input: leader - Pointer to a node at which to start the descent.
+ *
+ * Output: A pointer to a leaf node selected in a somewhat arbitrary
+ * manner.
+ *
+ * Notes: I wrote this function because I was using splay trees as a
+ * database cache. The cache had a maximum size on it, and I
+ * needed a way of choosing a node to sacrifice if the cache
+ * became full. In a splay tree, less recently accessed nodes
+ * tend toward the bottom of the tree, meaning that leaf nodes
+ * are good candidates for removal. (I really can't think of
+ * any other reason to use this function.)
+ * + In a simple binary tree or an AVL tree, the most recently
+ * added nodes tend to be nearer the bottom, making this a *bad*
+ * way to choose which node to remove from the cache.
+ * + Randomizing the traversal order is probably a good idea. You
+ * can improve the randomization of leaf node selection by passing
+ * in pointers to nodes other than the root node each time. A
+ * pointer to any node in the tree will do. Of course, if you
+ * pass a pointer to a leaf node you'll get the same thing back.
+ *
+ * ------------------------------------------------------------------------ **
+ */
+
+
+int ubi_btModuleID( int size, char *list[] );
+ /* ------------------------------------------------------------------------ **
+ * Returns a set of strings that identify the module.
+ *
+ * Input: size - The number of elements in the array <list>.
+ * list - An array of pointers of type (char *). This array
+ * should, initially, be empty. This function will fill
+ * in the array with pointers to strings.
+ * Output: The number of elements of <list> that were used. If this value
+ * is less than <size>, the values of the remaining elements are
+ * not guaranteed.
+ *
+ * Notes: Please keep in mind that the pointers returned indicate strings
+ * stored in static memory. Don't free() them, don't write over
+ * them, etc. Just read them.
+ * ------------------------------------------------------------------------ **
+ */
+
+/* -------------------------------------------------------------------------- **
+ * Masquarade...
+ *
+ * This set of defines allows you to write programs that will use any of the
+ * implemented binary tree modules (currently BinTree, AVLtree, and SplayTree).
+ * Instead of using ubi_bt..., use ubi_tr..., and select the tree type by
+ * including the appropriate module header.
+ */
+
+#define ubi_trItemPtr ubi_btItemPtr
+
+#define ubi_trNode ubi_btNode
+#define ubi_trNodePtr ubi_btNodePtr
+
+#define ubi_trRoot ubi_btRoot
+#define ubi_trRootPtr ubi_btRootPtr
+
+#define ubi_trCompFunc ubi_btCompFunc
+#define ubi_trActionRtn ubi_btActionRtn
+#define ubi_trKillNodeRtn ubi_btKillNodeRtn
+
+#define ubi_trSgn( x ) ubi_btSgn( x )
+
+#define ubi_trInitNode( Np ) ubi_btInitNode( (ubi_btNodePtr)(Np) )
+
+#define ubi_trInitTree( Rp, Cf, Fl ) \
+ ubi_btInitTree( (ubi_btRootPtr)(Rp), (ubi_btCompFunc)(Cf), (Fl) )
+
+#define ubi_trInsert( Rp, Nn, Ip, On ) \
+ ubi_btInsert( (ubi_btRootPtr)(Rp), (ubi_btNodePtr)(Nn), \
+ (ubi_btItemPtr)(Ip), (ubi_btNodePtr *)(On) )
+
+#define ubi_trRemove( Rp, Dn ) \
+ ubi_btRemove( (ubi_btRootPtr)(Rp), (ubi_btNodePtr)(Dn) )
+
+#define ubi_trLocate( Rp, Ip, Op ) \
+ ubi_btLocate( (ubi_btRootPtr)(Rp), \
+ (ubi_btItemPtr)(Ip), \
+ (ubi_trCompOps)(Op) )
+
+#define ubi_trFind( Rp, Ip ) \
+ ubi_btFind( (ubi_btRootPtr)(Rp), (ubi_btItemPtr)(Ip) )
+
+#define ubi_trNext( P ) ubi_btNext( (ubi_btNodePtr)(P) )
+
+#define ubi_trPrev( P ) ubi_btPrev( (ubi_btNodePtr)(P) )
+
+#define ubi_trFirst( P ) ubi_btFirst( (ubi_btNodePtr)(P) )
+
+#define ubi_trLast( P ) ubi_btLast( (ubi_btNodePtr)(P) )
+
+#define ubi_trFirstOf( Rp, Ip, P ) \
+ ubi_btFirstOf( (ubi_btRootPtr)(Rp), \
+ (ubi_btItemPtr)(Ip), \
+ (ubi_btNodePtr)(P) )
+
+#define ubi_trLastOf( Rp, Ip, P ) \
+ ubi_btLastOf( (ubi_btRootPtr)(Rp), \
+ (ubi_btItemPtr)(Ip), \
+ (ubi_btNodePtr)(P) )
+
+#define ubi_trTraverse( Rp, En, Ud ) \
+ ubi_btTraverse((ubi_btRootPtr)(Rp), (ubi_btActionRtn)(En), (void *)(Ud))
+
+#define ubi_trKillTree( Rp, Fn ) \
+ ubi_btKillTree( (ubi_btRootPtr)(Rp), (ubi_btKillNodeRtn)(Fn) )
+
+#define ubi_trLeafNode( Nd ) \
+ ubi_btLeafNode( (ubi_btNodePtr)(Nd) )
+
+#define ubi_trModuleID( s, l ) ubi_btModuleID( s, l )
+
+/* ========================================================================== */
+#endif /* ubi_BinTree_H */