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Diffstat (limited to 'source3/ubi_BinTree.c')
| -rw-r--r-- | source3/ubi_BinTree.c | 1042 |
1 files changed, 0 insertions, 1042 deletions
diff --git a/source3/ubi_BinTree.c b/source3/ubi_BinTree.c deleted file mode 100644 index e6db1a4816..0000000000 --- a/source3/ubi_BinTree.c +++ /dev/null @@ -1,1042 +0,0 @@ -/* ========================================================================== ** - * ubi_BinTree.c - * - * 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. - * - * -------------------------------------------------------------------------- ** - * - * $Log: ubi_BinTree.c,v $ - * Revision 1.1 1997/10/09 04:09:52 crh - * This is my library of lists and trees. My hope is to replace all of the - * hard coded linked lists that are currently used in Samba with calls to - * these modules. This should make the code simpler, smaller, and (I hope) - * faster. The tree code, in particular, should speed up processing where - * large lists are involved. - * - * Chris -)----- - * - * 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_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). - * - * ========================================================================== ** - */ - -#include "ubi_BinTree.h" /* Header for this module */ -#include <stdlib.h> /* Standard C definitions. */ - -/* ========================================================================== ** - * Static data. - */ - -static char ModuleID[] = "ubi_BinTree\n\ -\t$Revision: 1.1 $\n\ -\t$Date: 1997/10/09 04:09:52 $\n\ -\t$Author: 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. - * ------------------------------------------------------------------------ ** - */ - { - char tmp; - - while( p && (( tmp = AbNormal((*cmp)(FindMe, p)) ) != EQUAL) ) - 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_sex = EQUAL; - char tmp_cmp; - - while( tmp_p && (EQUAL != (tmp_cmp = AbNormal((*CmpFunc)(findme, tmp_p)))) ) - { - tmp_pp = tmp_p; /* Keep track of previous node. */ - tmp_sex = 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_sex; - 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! - * ------------------------------------------------------------------ * - */ - { - register int i; - register int btNodeSize = sizeof( ubi_btNode ); - - for( i = 0; i < btNodeSize; i++ ) /* Copy node internals to new node. */ - ((unsigned char *)newnode)[i] = ((unsigned char *)oldnode)[i]; - (*parent) = newnode; /* Old node's parent points to new child. */ - /* Now tell the children about their new step-parent. */ - if( oldnode->Link[LEFT ] ) (oldnode->Link[LEFT ])->Link[PARENT] = newnode; - if( oldnode->Link[RIGHT] ) (oldnode->Link[RIGHT])->Link[PARENT] = 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( Node1->Link[PARENT] ) - Parent = &((Node1->Link[PARENT])->Link[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( Node2->Link[PARENT] ) - Parent = &((Node2->Link[PARENT])->Link[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( dummy_p->Link[PARENT] ) - Parent = &((dummy_p->Link[PARENT])->Link[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 char 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. - * ------------------------------------------------------------------------ ** - */ - { - ubi_btNodePtr Q = NULL; - - while( P ) - { - Q = P; - P = P->Link[ whichway ]; - } - return( Q ); - } /* SubSlide */ - -static ubi_btNodePtr Neighbor( register ubi_btNodePtr P, - register char 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( P->Link[ whichway ] ) - return( SubSlide( P->Link[ whichway ], (char)RevWay(whichway) ) ); - else - while( P->Link[ PARENT ] ) - { - if( (P->Link[ PARENT ])->Link[ whichway ] == P ) - P = P->Link[ PARENT ]; - else - return( P->Link[ PARENT ] ); - } - } - return( NULL ); - } /* Neighbor */ - -static ubi_btNodePtr Border( ubi_btRootPtr RootPtr, - ubi_btItemPtr FindMe, - ubi_btNodePtr p, - char 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( !Dups_OK( RootPtr ) || (PARENT == 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[PARENT]; - while( q && (EQUAL == AbNormal( (*(RootPtr->cmp))(FindMe, q) )) ) - { - p = q; - q = p->Link[PARENT]; - } - - /* Next, move back down in the "whichway" direction. */ - q = p->Link[whichway]; - while( q ) - { - if( q = qFind( RootPtr->cmp, FindMe, 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 - * AbNormal() 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[ LEFT ] = NULL; - NodePtr->Link[ PARENT ] = NULL; - NodePtr->Link[ RIGHT ] = NULL; - NodePtr->gender = EQUAL; - return( NodePtr ); - } /* ubi_btInitNode */ - -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. - * - * ------------------------------------------------------------------------ ** - */ - { - 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( !(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 (!(*OldNode)) /* The easy one: we have a space for a new node! */ - { - if (!(parent)) - RootPtr->root = NewNode; - else - { - parent->Link[tmp] = NewNode; - NewNode->Link[PARENT] = 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( Dups_OK(RootPtr) ) /* Key exists, add duplicate */ - { - ubi_btNodePtr q; - - tmp = RIGHT; - q = (*OldNode); - *OldNode = NULL; - while( q ) - { - parent = q; - if( tmp == EQUAL ) tmp = RIGHT; - q = q->Link[tmp]; - if ( q ) - tmp = AbNormal( (*(RootPtr->cmp))(ItemPtr, q) ); - } - parent->Link[tmp] = NewNode; - NewNode->Link[PARENT] = 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( Ovwt_OK(RootPtr) ) /* Key exists, we replace */ - { - if (!(parent)) - ReplaceNode( &(RootPtr->root), *OldNode, NewNode ); - else - ReplaceNode( &(parent->Link[(*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; - char 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( (DeadNode->Link[LEFT]) && (DeadNode->Link[RIGHT]) ) - 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 (DeadNode->Link[PARENT]) - parentp = &((DeadNode->Link[PARENT])->Link[DeadNode->gender]); - else - parentp = &( RootPtr->root ); - - /* Now link the parent to the only grand-child and patch up the gender. */ - tmp = ((DeadNode->Link[LEFT])?LEFT:RIGHT); - - p = (DeadNode->Link[tmp]); - if( p ) - { - p->Link[PARENT] = DeadNode->Link[PARENT]; - 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( 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, LEFT ); - return( Neighbor( p, LEFT ) ); - case ubi_trGT: /* ...and then a jump to the right. */ - p = Border( RootPtr, FindMe, p, RIGHT ); - return( Neighbor( p, RIGHT ) ); - } - p = Border( RootPtr, FindMe, p, LEFT ); - 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( (LEFT == whichkid) ? Neighbor( parent, whichkid ) : parent ); - else - return( (RIGHT == 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, RIGHT ) ); - } /* 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, LEFT ) ); - } /* 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, LEFT ) ); - } /* 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, RIGHT ) ); - } /* 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. - * ------------------------------------------------------------------------ ** - */ - { - /* If our starting point is invalid, return NULL. */ - if( !p || AbNormal( (*(RootPtr->cmp))( MatchMe, p ) != EQUAL ) ) - return( NULL ); - return( Border( RootPtr, MatchMe, p, LEFT ) ); - } /* 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. - * ------------------------------------------------------------------------ ** - */ - { - /* If our starting point is invalid, return NULL. */ - if( !p || AbNormal( (*(RootPtr->cmp))( MatchMe, p ) != EQUAL ) ) - return( NULL ); - return( Border( RootPtr, MatchMe, p, RIGHT ) ); - } /* ubi_btLastOf */ - -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_btNodePtr p; - - if( !(p = ubi_btFirst( RootPtr->root )) ) return( ubi_trFALSE ); - - while( p ) - { - EachNode( p, UserData ); - p = ubi_btNext( p ); - } - return( ubi_trTRUE ); - } /* ubi_btTraverse */ - -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 p, q; - - if( !(RootPtr) || !(FreeNode) ) - return( ubi_trFALSE ); - - p = ubi_btFirst( RootPtr->root ); - while( p ) - { - q = p; - while( q->Link[RIGHT] ) - q = SubSlide( q->Link[RIGHT], LEFT ); - p = q->Link[PARENT]; - if( p ) - p->Link[ ((p->Link[LEFT] == q)?LEFT:RIGHT) ] = NULL; - FreeNode((void *)q); - } - - (void)ubi_btInitTree( RootPtr, - RootPtr->cmp, - RootPtr->flags ); - return( ubi_trTRUE ); - } /* 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. - * - * 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. - * - * ------------------------------------------------------------------------ ** - */ - { - ubi_btNodePtr follower = NULL; - int whichway = LEFT; - - while( NULL != leader ) - { - follower = leader; - leader = follower->Link[ whichway ]; - if( NULL == leader ) - { - whichway = RevWay( whichway ); - leader = follower->Link[ whichway ]; - } - } - - return( follower ); - } /* 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 */ - - -/* ========================================================================== */ |