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-/* ========================================================================== **
- * ubi_BinTree.c
- *
- * Copyright (C) 1991-1998 by Christopher R. Hertel
- *
- * Email: crh@ubiqx.mn.org
- * -------------------------------------------------------------------------- **
- *
- * This module implements a simple binary tree.
- *
- * -------------------------------------------------------------------------- **
- *
- * 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.
- *
- * -------------------------------------------------------------------------- **
- *
- * Log: ubi_BinTree.c,v
- * Revision 4.12 2004/06/06 04:51:56 crh
- * Fixed a small typo in ubi_BinTree.c (leftover testing cruft).
- * Did a small amount of formatting touchup to ubi_BinTree.h.
- *
- * Revision 4.11 2004/06/06 03:14:09 crh
- * Rewrote the ubi_btLeafNode() function. It now takes several paths in an
- * effort to find a deeper leaf node. There is a small amount of extra
- * overhead, but it is limited.
- *
- * Revision 4.10 2000/06/06 20:38:40 crh
- * In the ReplaceNode() function, the old node header was being copied
- * to the new node header using a byte-by-byte copy. This was causing
- * the 'insure' software testing program to report a memory leak. The
- * fix was to do a simple assignement: *newnode = *oldnode;
- * This quieted the (errant) memory leak reports and is probably a bit
- * faster than the bytewise copy.
- *
- * Revision 4.9 2000/01/08 23:24:30 crh
- * Clarified a variety of if( pointer ) lines, replacing them with
- * if( NULL != pointer ). This is more correct, and I have heard
- * of at least one (obscure?) system out there that uses a non-zero
- * value for NULL.
- * Also, speed improvement in Neighbor(). It was comparing pointers
- * when it could have compared two gender values. The pointer
- * comparison was somewhat indirect (does pointer equal the pointer
- * of the parent of the node pointed to by pointer). Urq.
- *
- * Revision 4.8 1999/09/22 03:40:30 crh
- * Modified ubi_btTraverse() and ubi_btKillTree(). They now return an
- * unsigned long indicating the number of nodes processed. The change
- * is subtle. An empty tree formerly returned False, and now returns
- * zero.
- *
- * Revision 4.7 1998/10/21 06:14:42 crh
- * Fixed bugs in FirstOf() and LastOf() reported by Massimo Campostrini.
- * See function comments.
- *
- * Revision 4.6 1998/07/25 17:02:10 crh
- * Added the ubi_trNewTree() macro.
- *
- * Revision 4.5 1998/06/04 21:29:27 crh
- * Upper-cased defined constants (eg UBI_BINTREE_H) in some header files.
- * This is more "standard", and is what people expect. Weird, eh?
- *
- * Revision 4.4 1998/06/03 17:42:46 crh
- * Further fiddling with sys_include.h. It's now in ubi_BinTree.h which is
- * included by all of the binary tree files.
- *
- * Reminder: Some of the ubi_tr* macros in ubi_BinTree.h are redefined in
- * ubi_AVLtree.h and ubi_SplayTree.h. This allows easy swapping
- * of tree types by simply changing a header. Unfortunately, the
- * macro redefinitions in ubi_AVLtree.h and ubi_SplayTree.h will
- * conflict if used together. You must either choose a single tree
- * type, or use the underlying function calls directly. Compare
- * the two header files for more information.
- *
- * Revision 4.3 1998/06/02 01:28:43 crh
- * Changed ubi_null.h to sys_include.h to make it more generic.
- *
- * Revision 4.2 1998/05/20 04:32:36 crh
- * The C file now includes ubi_null.h. See ubi_null.h for more info.
- * Also, the balance and gender fields of the node were declared as
- * signed char. As I understand it, at least one SunOS or Solaris
- * compiler doesn't like "signed char". The declarations were
- * wrong anyway, so I changed them to simple "char".
- *
- * Revision 4.1 1998/03/31 06:11:57 crh
- * Thomas Aglassinger sent E'mail pointing out errors in the
- * dereferencing of function pointers, and a missing typecast.
- * Thanks, Thomas!
- *
- * Revision 4.0 1998/03/10 03:19:22 crh
- * Added the AVL field 'balance' to the ubi_btNode structure. This means
- * that all BinTree modules now use the same basic node structure, which
- * greatly simplifies the AVL module.
- * Decided that this was a big enough change to justify a new major revision
- * number. 3.0 was an error, so we're at 4.0.
- *
- * Revision 2.6 1998/01/24 06:27:46 crh
- * Added ubi_trCount() macro.
- *
- * Revision 2.5 1997/12/23 03:56:29 crh
- * In this version, all constants & macros defined in the header file have
- * the ubi_tr prefix. Also cleaned up anything that gcc complained about
- * when run with '-pedantic -fsyntax-only -Wall'.
- *
- * Revision 2.4 1997/07/26 04:11:10 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 05:16:17 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 22:00:07 CRH
- * Ubisized!
- *
- * Revision 2.1 95/03/09 23:37:10 CRH
- * Added the ModuleID static string and function. These modules are now
- * self-identifying.
- *
- * Revision 2.0 95/02/27 22:00:17 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 22:44:59 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_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).
- *
- * ========================================================================== **
- */
-
-#include "ubi_BinTree.h" /* Header for this module. */
-
-
-/* ========================================================================== **
- * Static data.
- */
-
-static char ModuleID[] = "ubi_BinTree\n\
-\tRevision: 4.12\n\
-\tDate: 2004/06/06 04:51:56\n\
-\tAuthor: crh\n";
-
-/* ========================================================================== **
- * Internal (private) functions.
- */
-
-static ubi_btNodePtr qFind( ubi_btCompFunc cmp,
- ubi_btItemPtr FindMe,
- register ubi_btNodePtr p )
- /* ------------------------------------------------------------------------ **
- * This function performs a non-recursive search of a tree for a node
- * matching a specific key. It is called "qFind()" because it is
- * faster that TreeFind (below).
- *
- * Input:
- * cmp - a pointer to the tree's comparison function.
- * FindMe - a pointer to the key value for which to search.
- * p - a pointer to the starting point of the search. <p>
- * is considered to be the root of a subtree, and only
- * the subtree will be searched.
- *
- * 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.
- * ------------------------------------------------------------------------ **
- */
- {
- int tmp;
-
- while( (NULL != p)
- && ((tmp = ubi_trAbNormal( (*cmp)(FindMe, p) )) != ubi_trEQUAL) )
- p = p->Link[tmp];
-
- return( p );
- } /* qFind */
-
-static ubi_btNodePtr TreeFind( ubi_btItemPtr findme,
- ubi_btNodePtr p,
- ubi_btNodePtr *parentp,
- char *gender,
- ubi_btCompFunc CmpFunc )
- /* ------------------------------------------------------------------------ **
- * TreeFind() searches a tree for a given value (findme). It will return a
- * pointer to the target node, if found, or NULL if the target node was not
- * found.
- *
- * TreeFind() also returns, via parameters, a pointer to the parent of the
- * target node, and a LEFT or RIGHT value indicating which child of the
- * parent is the target node. *If the target is not found*, then these
- * values indicate the place at which the target *should be found*. This
- * is useful when inserting a new node into a tree or searching for nodes
- * "near" the target node.
- *
- * The parameters are:
- *
- * findme - is a pointer to the key information to be searched for.
- * p - points to the root of the tree to be searched.
- * parentp - will return a pointer to a pointer to the !parent! of the
- * target node, which can be especially usefull if the target
- * was not found.
- * gender - returns LEFT or RIGHT to indicate which child of *parentp
- * was last searched.
- * CmpFunc - points to the comparison function.
- *
- * This function is called by ubi_btLocate() and ubi_btInsert().
- * ------------------------------------------------------------------------ **
- */
- {
- register ubi_btNodePtr tmp_p = p;
- ubi_btNodePtr tmp_pp = NULL;
- char tmp_gender = ubi_trEQUAL;
- int tmp_cmp;
-
- while( (NULL != tmp_p)
- && (ubi_trEQUAL != (tmp_cmp = ubi_trAbNormal((*CmpFunc)(findme, tmp_p)))) )
- {
- tmp_pp = tmp_p; /* Keep track of previous node. */
- tmp_gender = (char)tmp_cmp; /* Keep track of sex of child. */
- tmp_p = tmp_p->Link[tmp_cmp]; /* Go to child. */
- }
- *parentp = tmp_pp; /* Return results. */
- *gender = tmp_gender;
- return( tmp_p );
- } /* TreeFind */
-
-static void ReplaceNode( ubi_btNodePtr *parent,
- ubi_btNodePtr oldnode,
- ubi_btNodePtr newnode )
- /* ------------------------------------------------------------------------ **
- * Remove node oldnode from the tree, replacing it with node newnode.
- *
- * Input:
- * parent - A pointer to he parent pointer of the node to be
- * replaced. <parent> may point to the Link[] field of
- * a parent node, or it may indicate the root pointer at
- * the top of the tree.
- * oldnode - A pointer to the node that is to be replaced.
- * newnode - A pointer to the node that is to be installed in the
- * place of <*oldnode>.
- *
- * Notes: Don't forget to free oldnode.
- * Also, this function used to have a really nasty typo
- * bug. "oldnode" and "newnode" were swapped in the line
- * that now reads:
- * ((unsigned char *)newnode)[i] = ((unsigned char *)oldnode)[i];
- * Bleah!
- * ------------------------------------------------------------------------ **
- */
- {
- *newnode = *oldnode; /* Copy node internals to new node. */
-
- (*parent) = newnode; /* Old node's parent points to new child. */
- /* Now tell the children about their new step-parent. */
- if( oldnode->Link[ubi_trLEFT] )
- (oldnode->Link[ubi_trLEFT])->Link[ubi_trPARENT] = newnode;
- if( oldnode->Link[ubi_trRIGHT] )
- (oldnode->Link[ubi_trRIGHT])->Link[ubi_trPARENT] = newnode;
- } /* ReplaceNode */
-
-static void SwapNodes( ubi_btRootPtr RootPtr,
- ubi_btNodePtr Node1,
- ubi_btNodePtr Node2 )
- /* ------------------------------------------------------------------------ **
- * This function swaps two nodes in the tree. Node1 will take the place of
- * Node2, and Node2 will fill in the space left vacant by Node 1.
- *
- * Input:
- * RootPtr - pointer to the tree header structure for this tree.
- * Node1 - \
- * > These are the two nodes which are to be swapped.
- * Node2 - /
- *
- * Notes:
- * This function does a three step swap, using a dummy node as a place
- * holder. This function is used by ubi_btRemove().
- * ------------------------------------------------------------------------ **
- */
- {
- ubi_btNodePtr *Parent;
- ubi_btNode dummy;
- ubi_btNodePtr dummy_p = &dummy;
-
- /* Replace Node 1 with the dummy, thus removing Node1 from the tree. */
- if( NULL != Node1->Link[ubi_trPARENT] )
- Parent = &((Node1->Link[ubi_trPARENT])->Link[(int)(Node1->gender)]);
- else
- Parent = &(RootPtr->root);
- ReplaceNode( Parent, Node1, dummy_p );
-
- /* Swap Node 1 with Node 2, placing Node 1 back into the tree. */
- if( NULL != Node2->Link[ubi_trPARENT] )
- Parent = &((Node2->Link[ubi_trPARENT])->Link[(int)(Node2->gender)]);
- else
- Parent = &(RootPtr->root);
- ReplaceNode( Parent, Node2, Node1 );
-
- /* Swap Node 2 and the dummy, thus placing Node 2 back into the tree. */
- if( NULL != dummy_p->Link[ubi_trPARENT] )
- Parent = &((dummy_p->Link[ubi_trPARENT])->Link[(int)(dummy_p->gender)]);
- else
- Parent = &(RootPtr->root);
- ReplaceNode( Parent, dummy_p, Node2 );
- } /* SwapNodes */
-
-/* -------------------------------------------------------------------------- **
- * These routines allow you to walk through the tree, forwards or backwards.
- */
-
-static ubi_btNodePtr SubSlide( register ubi_btNodePtr P,
- register int whichway )
- /* ------------------------------------------------------------------------ **
- * Slide down the side of a subtree.
- *
- * Given a starting node, this function returns a pointer to the LEFT-, or
- * RIGHT-most descendent, *or* (if whichway is PARENT) to the tree root.
- *
- * Input: P - a pointer to a starting place.
- * whichway - the direction (LEFT, RIGHT, or PARENT) in which to
- * travel.
- * Output: A pointer to a node that is either the root, or has no
- * whichway-th child but is within the subtree of P. Note that
- * the return value may be the same as P. The return value *will
- * be* NULL if P is NULL.
- * ------------------------------------------------------------------------ **
- */
- {
-
- if( NULL != P )
- while( NULL != P->Link[ whichway ] )
- P = P->Link[ whichway ];
- return( P );
- } /* SubSlide */
-
-static ubi_btNodePtr Neighbor( register ubi_btNodePtr P,
- register int whichway )
- /* ------------------------------------------------------------------------ **
- * Given starting point p, return the (key order) next or preceeding node
- * in the tree.
- *
- * Input: P - Pointer to our starting place node.
- * whichway - the direction in which to travel to find the
- * neighbor, i.e., the RIGHT neighbor or the LEFT
- * neighbor.
- *
- * Output: A pointer to the neighboring node, or NULL if P was NULL.
- *
- * Notes: If whichway is PARENT, the results are unpredictable.
- * ------------------------------------------------------------------------ **
- */
- {
- if( P )
- {
- if( NULL != P->Link[ whichway ] )
- return( SubSlide( P->Link[ whichway ], (char)ubi_trRevWay(whichway) ) );
- else
- while( NULL != P->Link[ ubi_trPARENT ] )
- {
- if( whichway == P->gender )
- P = P->Link[ ubi_trPARENT ];
- else
- return( P->Link[ ubi_trPARENT ] );
- }
- }
- return( NULL );
- } /* Neighbor */
-
-static ubi_btNodePtr Border( ubi_btRootPtr RootPtr,
- ubi_btItemPtr FindMe,
- ubi_btNodePtr p,
- int whichway )
- /* ------------------------------------------------------------------------ **
- * Given starting point p, which has a key value equal to *FindMe, locate
- * the first (index order) node with the same key value.
- *
- * This function is useful in trees that have can have duplicate keys.
- * For example, consider the following tree:
- * Tree Traversal
- * 2 If <p> points to the root and <whichway> is RIGHT, 3
- * / \ then the return value will be a pointer to the / \
- * 2 2 RIGHT child of the root node. The tree on 2 5
- * / / \ the right shows the order of traversal. / / \
- * 1 2 3 1 4 6
- *
- * Input: RootPtr - Pointer to the tree root structure.
- * FindMe - Key value for comparisons.
- * p - Pointer to the starting-point node.
- * whichway - the direction in which to travel to find the
- * neighbor, i.e., the RIGHT neighbor or the LEFT
- * neighbor.
- *
- * Output: A pointer to the first (index, or "traversal", order) node with
- * a Key value that matches *FindMe.
- *
- * Notes: If whichway is PARENT, or if the tree does not allow duplicate
- * keys, this function will return <p>.
- * ------------------------------------------------------------------------ **
- */
- {
- register ubi_btNodePtr q;
-
- /* Exit if there's nothing that can be done. */
- if( !ubi_trDups_OK( RootPtr ) || (ubi_trPARENT == whichway) )
- return( p );
-
- /* First, if needed, move up the tree. We need to get to the root of the
- * subtree that contains all of the matching nodes.
- */
- q = p->Link[ubi_trPARENT];
- while( (NULL != q)
- && (ubi_trEQUAL == ubi_trAbNormal( (*(RootPtr->cmp))(FindMe, q) )) )
- {
- p = q;
- q = p->Link[ubi_trPARENT];
- }
-
- /* Next, move back down in the "whichway" direction. */
- q = p->Link[whichway];
- while( NULL != q )
- {
- q = qFind( RootPtr->cmp, FindMe, q );
- if( q )
- {
- p = q;
- q = p->Link[whichway];
- }
- }
- return( p );
- } /* Border */
-
-
-/* ========================================================================== **
- * Exported utilities.
- */
-
-long ubi_btSgn( register 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
- * ubi_trAbNormal() conversion macro!
- *
- * ------------------------------------------------------------------------ **
- */
- {
- return( (x)?((x>0)?(1):(-1)):(0) );
- } /* ubi_btSgn */
-
-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).
- * ------------------------------------------------------------------------ **
- */
- {
- NodePtr->Link[ ubi_trLEFT ] = NULL;
- NodePtr->Link[ ubi_trPARENT ] = NULL;
- NodePtr->Link[ ubi_trRIGHT ] = NULL;
- NodePtr->gender = ubi_trEQUAL;
- NodePtr->balance = ubi_trEQUAL;
- return( NodePtr );
- } /* ubi_btInitNode */
-
-ubi_btRootPtr ubi_btInitTree( ubi_btRootPtr RootPtr,
- ubi_btCompFunc CompFunc,
- 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.
- *
- * ------------------------------------------------------------------------ **
- */
- {
- if( RootPtr )
- {
- RootPtr->root = NULL;
- RootPtr->count = 0L;
- RootPtr->cmp = CompFunc;
- RootPtr->flags = (Flags & ubi_trDUPKEY) ? ubi_trDUPKEY : Flags;
- } /* There are only two supported flags, and they are
- * mutually exclusive. ubi_trDUPKEY takes precedence
- * over ubi_trOVERWRITE.
- */
- return( RootPtr );
- } /* ubi_btInitTree */
-
-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 OtherP,
- parent = NULL;
- char tmp;
-
- if( NULL == OldNode ) /* If they didn't give us a pointer, supply our own. */
- OldNode = &OtherP;
-
- (void)ubi_btInitNode( NewNode ); /* Init the new node's BinTree fields. */
-
- /* Find a place for the new node. */
- *OldNode = TreeFind(ItemPtr, (RootPtr->root), &parent, &tmp, (RootPtr->cmp));
-
- /* Now add the node to the tree... */
- if( NULL == (*OldNode) ) /* The easy one: we have a space for a new node! */
- {
- if( NULL == parent )
- RootPtr->root = NewNode;
- else
- {
- parent->Link[(int)tmp] = NewNode;
- NewNode->Link[ubi_trPARENT] = parent;
- NewNode->gender = tmp;
- }
- (RootPtr->count)++;
- return( ubi_trTRUE );
- }
-
- /* If we reach this point, we know that a duplicate node exists. This
- * section adds the node to the tree if duplicate keys are allowed.
- */
- if( ubi_trDups_OK(RootPtr) ) /* Key exists, add duplicate */
- {
- ubi_btNodePtr q;
-
- tmp = ubi_trRIGHT;
- q = (*OldNode);
- *OldNode = NULL;
- while( NULL != q )
- {
- parent = q;
- if( tmp == ubi_trEQUAL )
- tmp = ubi_trRIGHT;
- q = q->Link[(int)tmp];
- if ( q )
- tmp = ubi_trAbNormal( (*(RootPtr->cmp))(ItemPtr, q) );
- }
- parent->Link[(int)tmp] = NewNode;
- NewNode->Link[ubi_trPARENT] = parent;
- NewNode->gender = tmp;
- (RootPtr->count)++;
- return( ubi_trTRUE );
- }
-
- /* If we get to *this* point, we know that we are not allowed to have
- * duplicate nodes, but our node keys match, so... may we replace the
- * old one?
- */
- if( ubi_trOvwt_OK(RootPtr) ) /* Key exists, we replace */
- {
- if( NULL == parent )
- ReplaceNode( &(RootPtr->root), *OldNode, NewNode );
- else
- ReplaceNode( &(parent->Link[(int)((*OldNode)->gender)]),
- *OldNode, NewNode );
- return( ubi_trTRUE );
- }
-
- return( ubi_trFALSE ); /* Failure: could not replace an existing node. */
- } /* ubi_btInsert */
-
-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 p,
- *parentp;
- int tmp;
-
- /* if the node has both left and right subtrees, then we have to swap
- * it with another node. The other node we choose will be the Prev()ious
- * node, which is garunteed to have no RIGHT child.
- */
- if( (NULL != DeadNode->Link[ubi_trLEFT])
- && (NULL != DeadNode->Link[ubi_trRIGHT]) )
- SwapNodes( RootPtr, DeadNode, ubi_btPrev( DeadNode ) );
-
- /* The parent of the node to be deleted may be another node, or it may be
- * the root of the tree. Since we're not sure, it's best just to have
- * a pointer to the parent pointer, whatever it is.
- */
- if( NULL == DeadNode->Link[ubi_trPARENT] )
- parentp = &( RootPtr->root );
- else
- parentp = &((DeadNode->Link[ubi_trPARENT])->Link[(int)(DeadNode->gender)]);
-
- /* Now link the parent to the only grand-child and patch up the gender. */
- tmp = ((DeadNode->Link[ubi_trLEFT])?ubi_trLEFT:ubi_trRIGHT);
-
- p = (DeadNode->Link[tmp]);
- if( NULL != p )
- {
- p->Link[ubi_trPARENT] = DeadNode->Link[ubi_trPARENT];
- p->gender = DeadNode->gender;
- }
- (*parentp) = p;
-
- /* Finished, reduce the node count and return. */
- (RootPtr->count)--;
- return( DeadNode );
- } /* ubi_btRemove */
-
-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().
- * ------------------------------------------------------------------------ **
- */
- {
- register ubi_btNodePtr p;
- ubi_btNodePtr parent;
- char whichkid;
-
- /* Start by searching for a matching node. */
- p = TreeFind( FindMe,
- RootPtr->root,
- &parent,
- &whichkid,
- RootPtr->cmp );
-
- if( NULL != p ) /* If we have found a match, we can resolve as follows: */
- {
- switch( CompOp )
- {
- case ubi_trLT: /* It's just a jump to the left... */
- p = Border( RootPtr, FindMe, p, ubi_trLEFT );
- return( Neighbor( p, ubi_trLEFT ) );
- case ubi_trGT: /* ...and then a jump to the right. */
- p = Border( RootPtr, FindMe, p, ubi_trRIGHT );
- return( Neighbor( p, ubi_trRIGHT ) );
- default:
- p = Border( RootPtr, FindMe, p, ubi_trLEFT );
- return( p );
- }
- }
-
- /* Else, no match. */
- if( ubi_trEQ == CompOp ) /* If we were looking for an exact match... */
- return( NULL ); /* ...forget it. */
-
- /* We can still return a valid result for GT, GE, LE, and LT.
- * <parent> points to a node with a value that is either just before or
- * just after the target value.
- * Remaining possibilities are LT and GT (including LE & GE).
- */
- if( (ubi_trLT == CompOp) || (ubi_trLE == CompOp) )
- return( (ubi_trLEFT == whichkid) ? Neighbor( parent, whichkid ) : parent );
- else
- return( (ubi_trRIGHT == whichkid) ? Neighbor( parent, whichkid ) : parent );
- } /* ubi_btLocate */
-
-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().
- * ------------------------------------------------------------------------ **
- */
- {
- return( qFind( RootPtr->cmp, FindMe, RootPtr->root ) );
- } /* ubi_btFind */
-
-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.
- * ------------------------------------------------------------------------ **
- */
- {
- return( Neighbor( P, ubi_trRIGHT ) );
- } /* ubi_btNext */
-
-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.
- * ------------------------------------------------------------------------ **
- */
- {
- return( Neighbor( P, ubi_trLEFT ) );
- } /* ubi_btPrev */
-
-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.
- * ------------------------------------------------------------------------ **
- */
- {
- return( SubSlide( P, ubi_trLEFT ) );
- } /* ubi_btFirst */
-
-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.
- * ------------------------------------------------------------------------ **
- */
- {
- return( SubSlide( P, ubi_trRIGHT ) );
- } /* ubi_btLast */
-
-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.
- *
- * 4.7: Bug found & fixed by Massimo Campostrini,
- * Istituto Nazionale di Fisica Nucleare, Sezione di Pisa.
- *
- * ------------------------------------------------------------------------ **
- */
- {
- /* If our starting point is invalid, return NULL. */
- if( (NULL == p)
- || (ubi_trEQUAL != ubi_trAbNormal( (*(RootPtr->cmp))( MatchMe, p ) )) )
- return( NULL );
- return( Border( RootPtr, MatchMe, p, ubi_trLEFT ) );
- } /* ubi_btFirstOf */
-
-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.
- *
- * 4.7: Bug found & fixed by Massimo Campostrini,
- * Istituto Nazionale di Fisica Nucleare, Sezione di Pisa.
- *
- * ------------------------------------------------------------------------ **
- */
- {
- /* If our starting point is invalid, return NULL. */
- if( (NULL != p)
- || (ubi_trEQUAL != ubi_trAbNormal( (*(RootPtr->cmp))( MatchMe, p ) )) )
- return( NULL );
- return( Border( RootPtr, MatchMe, p, ubi_trRIGHT ) );
- } /* ubi_btLastOf */
-
-unsigned long 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 count of the number of nodes visited. This will be zero
- * if the tree is empty.
- *
- * ------------------------------------------------------------------------ **
- */
- {
- ubi_btNodePtr p = ubi_btFirst( RootPtr->root );
- unsigned long count = 0;
-
- while( NULL != p )
- {
- (*EachNode)( p, UserData );
- count++;
- p = ubi_btNext( p );
- }
- return( count );
- } /* ubi_btTraverse */
-
-unsigned long ubi_btKillTree( ubi_btRootPtr RootPtr,
- ubi_btKillNodeRtn FreeNode )
- /* ------------------------------------------------------------------------ **
- * Delete an entire tree (non-recursively) and reinitialize the ubi_btRoot
- * structure. Return a count of the number of nodes deleted.
- *
- * 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: The number of nodes removed from the tree.
- * A value of 0 will be returned if:
- * - The tree actually contains 0 entries.
- * - the value of <RootPtr> is NULL, in which case the tree is
- * assumed to be empty
- * - the value of <FreeNode> is NULL, in which case entries
- * cannot be removed, so 0 is returned. *Make sure that you
- * provide a valid value for <FreeNode>*.
- * In all other cases, you should get a positive value equal to
- * the value of RootPtr->count upon entry.
- *
- * ------------------------------------------------------------------------ **
- */
- {
- ubi_btNodePtr p, q;
- unsigned long count = 0;
-
- if( (NULL == RootPtr) || (NULL == FreeNode) )
- return( 0 );
-
- p = ubi_btFirst( RootPtr->root );
- while( NULL != p )
- {
- q = p;
- while( q->Link[ubi_trRIGHT] )
- q = SubSlide( q->Link[ubi_trRIGHT], ubi_trLEFT );
- p = q->Link[ubi_trPARENT];
- if( NULL != p )
- p->Link[ ((p->Link[ubi_trLEFT] == q)?ubi_trLEFT:ubi_trRIGHT) ] = NULL;
- (*FreeNode)((void *)q);
- count++;
- }
-
- /* overkill... */
- (void)ubi_btInitTree( RootPtr,
- RootPtr->cmp,
- RootPtr->flags );
- return( count );
- } /* ubi_btKillTree */
-
-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 but with an effort to dig deep.
- *
- * 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 in 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.
- * + In an unbalanced splay tree, if you simply traverse downward
- * until you hit a leaf node it is possible to accidentally
- * stumble onto a short path. The result will be a leaf node
- * that is actually very high in the tree--possibly a very
- * recently accessed node. Not good. This function can follow
- * multiple paths in an effort to find a leaf node deeper
- * in the tree. Following a single path, of course, is the
- * fastest way to find a leaf node. A complete traversal would
- * be sure to find the deepest leaf but would be very costly in
- * terms of time. This function uses a compromise that has
- * worked well in testing.
- *
- * ------------------------------------------------------------------------ **
- */
- {
- #define MAXPATHS 4 /* Set higher for more maximum paths, lower for fewer. */
- ubi_trNodePtr p[MAXPATHS];
- ubi_trNodePtr q[MAXPATHS];
- int whichway = ubi_trLEFT;
- int paths;
- int i, j;
-
- /* If the subtree is empty, return NULL.
- */
- if( NULL == leader )
- return( NULL );
-
- /* Initialize the p[] array with a pointer to the single node we've been
- * given as a starting point.
- */
- p[0] = leader;
- paths = 1;
- while( paths > 0 )
- {
- for( i = 0; i < paths; i++ )
- q[i] = p[i];
-
- for( i = j = 0; (i < paths) && (j < MAXPATHS); i++ )
- {
- if( NULL != q[i]->Link[whichway] )
- p[j++] = q[i]->Link[whichway];
- whichway = ubi_trRevWay( whichway );
- if( (j < MAXPATHS) && (NULL != q[i]->Link[whichway]) )
- p[j++] = q[i]->Link[whichway];
- }
- paths = j;
- }
-
- return( q[0] );
- } /* ubi_btLeafNode */
-
-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.
- * ------------------------------------------------------------------------ **
- */
- {
- if( size > 0 )
- {
- list[0] = ModuleID;
- if( size > 1 )
- list[1] = NULL;
- return( 1 );
- }
- return( 0 );
- } /* ubi_btModuleID */
-
-
-/* ========================================================================== */