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-rw-r--r--source3/ubiqx/ubi_AVLtree.c143
-rw-r--r--source3/ubiqx/ubi_AVLtree.h118
-rw-r--r--source3/ubiqx/ubi_BinTree.c222
-rw-r--r--source3/ubiqx/ubi_BinTree.h269
-rw-r--r--source3/ubiqx/ubi_SplayTree.c108
-rw-r--r--source3/ubiqx/ubi_SplayTree.h73
6 files changed, 584 insertions, 349 deletions
diff --git a/source3/ubiqx/ubi_AVLtree.c b/source3/ubiqx/ubi_AVLtree.c
index a864b160b5..2cd8d1cbed 100644
--- a/source3/ubiqx/ubi_AVLtree.c
+++ b/source3/ubiqx/ubi_AVLtree.c
@@ -9,11 +9,9 @@
* This module provides an implementation of AVL height balanced binary
* trees. (Adelson-Velskii, Landis 1962)
*
- * This header file contains the basic AVL structure and pointer typedefs
- * as well as the prototypes needed to access the functions in the AVL
- * module ubi_AVLtree. The .c file implements the low-level height balancing
- * routines that manage the AVL tree, plus all of the basic primops for
- * adding, searching for, and deleting nodes.
+ * This file implements the core of the height-balanced (AVL) tree management
+ * routines. The header file, ubi_AVLtree.h, contains function prototypes
+ * for all "exported" functions.
*
* -------------------------------------------------------------------------- **
*
@@ -34,22 +32,89 @@
* -------------------------------------------------------------------------- **
*
* Log: ubi_AVLtree.c,v
- * Revision 3.1 1997/12/18 06:26:51 crh
- * Fixed some comment bugs.
+ * Revision 2.5 1997/12/23 04:00:42 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 3.0 1997/12/08 05:38:55 crh
- * This is a new major revision level. The handling of the pointers in the
- * ubi_trNode structure was redesigned. The result is that there are fewer
- * macros floating about, and fewer cases in which values have to be
- * incremented or decremented. See ubi_BinTree for more information.
+ * Revision 2.4 1997/07/26 04:36:20 crh
+ * Andrew Leppard, aka "Grazgur", discovered that I still had my brains tied
+ * on backwards with respect to node deletion. I did some more digging and
+ * discovered that I was not changing the balance values correctly in the
+ * single rotation functions. Double rotation was working correctly because
+ * the formula for changing the balance values is the same for insertion or
+ * deletion. Not so for single rotation.
*
- * Revision 2; 1995/03/05 - 1997/12/07:
- * An overhaul to the node delete process. I had gotten it wrong in a
- * couple of places, thought I'd fixed it, and then found that I'd missed
- * something more. Thanks to Andrew Leppard for the bug report!
+ * I have tested the fix by loading the tree with over 44 thousand names,
+ * deleting 2,629 of them (all those in which the second character is 'u')
+ * and then walking the tree recursively to verify that the balance factor of
+ * each node is correct. Passed.
*
- * Revision 1; 93/10/15 - 95/03/05:
- * Added the ubi_tr defines. See ubi_BinTree.h for more info.
+ * Thanks Andrew!
+ *
+ * Also:
+ * + Changed ubi_TRUE and ubi_FALSE to ubi_trTRUE and ubi_trFALSE.
+ * + Rewrote the ubi_tr<func> macros because they weren't doing what I'd
+ * hoped they would do (see the bottom of the header file). They work now.
+ *
+ * Revision 2.3 1997/06/03 04:41:35 crh
+ * Changed TRUE and FALSE to ubi_TRUE and ubi_FALSE to avoid causing
+ * problems.
+ *
+ * Revision 2.2 1995/10/03 22:16:01 CRH
+ * Ubisized!
+ *
+ * Revision 2.1 95/03/09 23:45:59 CRH
+ * Added the ModuleID static string and function. These modules are now
+ * self-identifying.
+ *
+ * Revision 2.0 95/03/05 14:10:51 CRH
+ * This revision of ubi_AVLtree coincides with revision 2.0 of ubi_BinTree,
+ * and so includes all of the changes to that module. In addition, a bug in
+ * the node deletion process has been fixed.
+ *
+ * After rewriting the Locate() function in ubi_BinTree, I decided that it was
+ * time to overhaul this module. In the process, I discovered a bug related
+ * to node deletion. To fix the bug, I wrote function Debalance(). A quick
+ * glance will show that it is very similar to the Rebalance() function. In
+ * previous versions of this module, I tried to include the functionality of
+ * Debalance() within Rebalance(), with poor results.
+ *
+ * Revision 1.0 93/10/15 22:58:56 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 - May, 1990 - Written by Christopher R. Hertel (CRH).
*
@@ -64,8 +129,8 @@
*/
static char ModuleID[] = "ubi_AVLtree\n\
-\tRevision: 3.1\n\
-\tDate: 1997/12/18 06:26:51 GMT\n\
+\tRevision: 2.5\n\
+\tDate: 1997/12/23 04:00:42\n\
\tAuthor: crh\n";
/* ========================================================================== **
@@ -101,7 +166,7 @@ static ubi_avlNodePtr L1( ubi_avlNodePtr p )
tmp->Link[ubi_trPARENT] = p->Link[ubi_trPARENT];
tmp->gender = p->gender;
if(tmp->Link[ubi_trPARENT])
- (tmp->Link[ubi_trPARENT])->Link[(tmp->gender)] = tmp;
+ (tmp->Link[ubi_trPARENT])->Link[(int)(tmp->gender)] = tmp;
p->Link[ubi_trPARENT] = tmp;
p->gender = ubi_trLEFT;
if( p->Link[ubi_trRIGHT] )
@@ -109,7 +174,7 @@ static ubi_avlNodePtr L1( ubi_avlNodePtr p )
p->Link[ubi_trRIGHT]->Link[ubi_trPARENT] = p;
(p->Link[ubi_trRIGHT])->gender = ubi_trRIGHT;
}
- p->balance -= tmp->balance;
+ p->balance -= ubi_trNormalize( tmp->balance );
(tmp->balance)--;
return( tmp );
} /* L1 */
@@ -133,7 +198,7 @@ static ubi_avlNodePtr R1( ubi_avlNodePtr p )
tmp->Link[ubi_trPARENT] = p->Link[ubi_trPARENT];
tmp->gender = p->gender;
if(tmp->Link[ubi_trPARENT])
- (tmp->Link[ubi_trPARENT])->Link[(tmp->gender)] = tmp;
+ (tmp->Link[ubi_trPARENT])->Link[(int)(tmp->gender)] = tmp;
p->Link[ubi_trPARENT] = tmp;
p->gender = ubi_trRIGHT;
if(p->Link[ubi_trLEFT])
@@ -141,7 +206,7 @@ static ubi_avlNodePtr R1( ubi_avlNodePtr p )
p->Link[ubi_trLEFT]->Link[ubi_trPARENT] = p;
p->Link[ubi_trLEFT]->gender = ubi_trLEFT;
}
- p->balance -= tmp->balance;
+ p->balance -= ubi_trNormalize( tmp->balance );
(tmp->balance)++;
return( tmp );
} /* R1 */
@@ -183,7 +248,7 @@ static ubi_avlNodePtr L2( ubi_avlNodePtr tree )
tmp->Link[ubi_trLEFT]->gender = ubi_trLEFT;
}
if(newroot->Link[ubi_trPARENT])
- newroot->Link[ubi_trPARENT]->Link[newroot->gender] = newroot;
+ newroot->Link[ubi_trPARENT]->Link[(int)(newroot->gender)] = newroot;
switch( newroot->balance )
{
@@ -235,7 +300,7 @@ static ubi_avlNodePtr R2( ubi_avlNodePtr tree )
tmp->Link[ubi_trRIGHT]->gender = ubi_trRIGHT;
}
if(newroot->Link[ubi_trPARENT])
- newroot->Link[ubi_trPARENT]->Link[newroot->gender] = newroot;
+ newroot->Link[ubi_trPARENT]->Link[(int)(newroot->gender)] = newroot;
switch( newroot->balance )
{
@@ -251,7 +316,7 @@ static ubi_avlNodePtr R2( ubi_avlNodePtr tree )
} /* R2 */
-static ubi_avlNodePtr Adjust( ubi_avlNodePtr p, signed char LorR )
+static ubi_avlNodePtr Adjust( ubi_avlNodePtr p, char LorR )
/* ------------------------------------------------------------------------ **
* Adjust the balance value at node *p. If necessary, rotate the subtree
* rooted at p.
@@ -270,12 +335,12 @@ static ubi_avlNodePtr Adjust( ubi_avlNodePtr p, signed char LorR )
*/
{
if( p->balance != LorR )
- p->balance += LorR;
+ p->balance += ubi_trNormalize(LorR);
else
{
- signed char tallerbal; /* Balance of root of the taller subtree of p. */
+ char tallerbal; /* Balance value of the root of the taller subtree of p. */
- tallerbal = p->Link[LorR]->balance;
+ tallerbal = p->Link[(int)LorR]->balance;
if( ( ubi_trEQUAL == tallerbal ) || ( p->balance == tallerbal ) )
p = ( (ubi_trLEFT==LorR) ? R1(p) : L1(p) ); /* single rotation */
else
@@ -286,7 +351,7 @@ static ubi_avlNodePtr Adjust( ubi_avlNodePtr p, signed char LorR )
static ubi_avlNodePtr Rebalance( ubi_avlNodePtr Root,
ubi_avlNodePtr subtree,
- signed char LorR )
+ char LorR )
/* ------------------------------------------------------------------------ **
* Rebalance the tree following an insertion.
*
@@ -324,7 +389,7 @@ static ubi_avlNodePtr Rebalance( ubi_avlNodePtr Root,
static ubi_avlNodePtr Debalance( ubi_avlNodePtr Root,
ubi_avlNodePtr subtree,
- signed char LorR )
+ char LorR )
/* ------------------------------------------------------------------------ **
* Rebalance the tree following a deletion.
*
@@ -431,19 +496,19 @@ static void SwapNodes( ubi_btRootPtr RootPtr,
ubi_avlNodePtr dummy_p = &dummy;
if( Node1->Link[ubi_trPARENT] )
- Parent = &((Node1->Link[ubi_trPARENT])->Link[Node1->gender]);
+ Parent = &((Node1->Link[ubi_trPARENT])->Link[(int)(Node1->gender)]);
else
Parent = (ubi_avlNodePtr *)&(RootPtr->root);
ReplaceNode( Parent, Node1, dummy_p );
if( Node2->Link[ubi_trPARENT] )
- Parent = &((Node2->Link[ubi_trPARENT])->Link[Node2->gender]);
+ Parent = &((Node2->Link[ubi_trPARENT])->Link[(int)(Node2->gender)]);
else
Parent = (ubi_avlNodePtr *)&(RootPtr->root);
ReplaceNode( Parent, Node2, Node1 );
if( dummy_p->Link[ubi_trPARENT] )
- Parent = &((dummy_p->Link[ubi_trPARENT])->Link[dummy_p->gender]);
+ Parent = &((dummy_p->Link[ubi_trPARENT])->Link[(int)(dummy_p->gender)]);
else
Parent = (ubi_avlNodePtr *)&(RootPtr->root);
ReplaceNode( Parent, dummy_p, Node2 );
@@ -575,7 +640,7 @@ ubi_avlNodePtr ubi_avlRemove( ubi_btRootPtr RootPtr,
*/
if( DeadNode->Link[ubi_trPARENT] )
parentp = (ubi_btNodePtr *)
- &((DeadNode->Link[ubi_trPARENT])->Link[(DeadNode->gender)]);
+ &((DeadNode->Link[ubi_trPARENT])->Link[(int)(DeadNode->gender)]);
else
parentp = &( RootPtr->root );
@@ -586,9 +651,9 @@ ubi_avlNodePtr ubi_avlRemove( ubi_btRootPtr RootPtr,
(*parentp) = NULL;
else
{
- p = (ubi_btNodePtr)(DeadNode->Link[(DeadNode->balance)]);
- p->Link[ubi_trPARENT] = (ubi_btNodePtr)DeadNode->Link[ubi_trPARENT];
- p->gender = DeadNode->gender;
+ p = (ubi_btNodePtr)(DeadNode->Link[(int)(DeadNode->balance)]);
+ p->Link[ubi_trPARENT] = (ubi_btNodePtr)DeadNode->Link[ubi_trPARENT];
+ p->gender = DeadNode->gender;
(*parentp) = p;
}
RootPtr->root = (ubi_btNodePtr)Debalance( (ubi_avlNodePtr)RootPtr->root,
diff --git a/source3/ubiqx/ubi_AVLtree.h b/source3/ubiqx/ubi_AVLtree.h
index c7cac0ed1e..ebae7f3c13 100644
--- a/source3/ubiqx/ubi_AVLtree.h
+++ b/source3/ubiqx/ubi_AVLtree.h
@@ -35,22 +35,89 @@
*
* -------------------------------------------------------------------------- **
* Log: ubi_AVLtree.h,v
- * Revision 3.1 1997/12/18 06:27:01 crh
- * Fixed some comment bugs.
+ * Revision 2.5 1997/12/23 04:00:15 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 3.0 1997/12/08 05:39:01 crh
- * This is a new major revision level. The handling of the pointers in the
- * ubi_trNode structure was redesigned. The result is that there are fewer
- * macros floating about, and fewer cases in which values have to be
- * incremented or decremented. See ubi_BinTree for more information.
+ * Revision 2.4 1997/07/26 04:36:23 crh
+ * Andrew Leppard, aka "Grazgur", discovered that I still had my brains tied
+ * on backwards with respect to node deletion. I did some more digging and
+ * discovered that I was not changing the balance values correctly in the
+ * single rotation functions. Double rotation was working correctly because
+ * the formula for changing the balance values is the same for insertion or
+ * deletion. Not so for single rotation.
*
- * Revision 2; 1995/03/05 - 1997/12/07:
- * An overhaul to the node delete process. I had gotten it wrong in a
- * couple of places, thought I'd fixed it, and then found that I'd missed
- * something more. Thanks to Andrew Leppard for the bug report!
+ * I have tested the fix by loading the tree with over 44 thousand names,
+ * deleting 2,629 of them (all those in which the second character is 'u')
+ * and then walking the tree recursively to verify that the balance factor of
+ * each node is correct. Passed.
+ *
+ * Thanks Andrew!
+ *
+ * Also:
+ * + Changed ubi_TRUE and ubi_FALSE to ubi_trTRUE and ubi_trFALSE.
+ * + Rewrote the ubi_tr<func> macros because they weren't doing what I'd
+ * hoped they would do (see the bottom of the header file). They work now.
+ *
+ * Revision 2.3 1997/06/03 05:22:07 crh
+ * Changed TRUE and FALSE to ubi_TRUE and ubi_FALSE to avoid causing
+ * problems.
+ *
+ * Revision 2.2 1995/10/03 22:15:47 CRH
+ * Ubisized!
+ *
+ * Revision 2.1 95/03/09 23:46:44 CRH
+ * Added the ModuleID static string and function. These modules are now
+ * self-identifying.
*
- * Revision 1; 93/10/15 - 95/03/05:
- * Added the ubi_tr defines. See ubi_BinTree.h for more info.
+ * Revision 2.0 95/03/05 14:11:22 CRH
+ * This revision of ubi_AVLtree coincides with revision 2.0 of ubi_BinTree,
+ * and so includes all of the changes to that module. In addition, a bug in
+ * the node deletion process has been fixed.
+ *
+ * After rewriting the Locate() function in ubi_BinTree, I decided that it was
+ * time to overhaul this module. In the process, I discovered a bug related
+ * to node deletion. To fix the bug, I wrote function Debalance(). A quick
+ * glance will show that it is very similar to the Rebalance() function. In
+ * previous versions of this module, I tried to include the functionality of
+ * Debalance() within Rebalance(), with poor results.
+ *
+ * Revision 1.0 93/10/15 22:58:48 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 - May, 1990 - Written by Christopher R. Hertel (CRH).
*
@@ -66,7 +133,6 @@
* header so that you can use the structure as a building block.
*
* The fields are as follows:
- * leftlink - A space filler. This field will be accessed as Link[-1].
* Link - An array of pointers. These pointers are manipulated by the
* BT and AVL routines, and indicate the left and right child
* nodes, plus the parent node. By keeping track of the parent
@@ -81,21 +147,25 @@
* indicates which subtree of the current node is longer, or if
* the subtrees are, in fact, balanced with respect to each
* other.
- *
+ * ------------------------------------------------------------------------- **
*/
-typedef struct ubi_avlNodeStruct
- {
- struct ubi_avlNodeStruct *leftlink;
- struct ubi_avlNodeStruct *Link[2];
- signed char gender;
- signed char balance;
- } ubi_avlNode;
+typedef struct ubi_avlNodeStruct {
+ struct ubi_avlNodeStruct
+ *Link[3]; /* Normal Binary Tree Node type. */
+ char gender; /* The node is either the RIGHT or LEFT child of its */
+ /* parent, or is the root node. */
+ char balance; /* In an AVL tree, each node is the root of a subtree */
+ /* that may be balanced, or be one node longer to the */
+ /* right or left. This field keeps track of the */
+ /* balance value of each node. */
+ } ubi_avlNode;
-typedef ubi_avlNode *ubi_avlNodePtr; /* a Pointer to an AVL node. */
+typedef ubi_avlNode *ubi_avlNodePtr; /* a Pointer to an AVL node */
/* -------------------------------------------------------------------------- **
- * Function prototypes...
+ * Function prototypes.
+ * -------------------------------------------------------------------------- **
*/
ubi_avlNodePtr ubi_avlInitNode( ubi_avlNodePtr NodePtr );
diff --git a/source3/ubiqx/ubi_BinTree.c b/source3/ubiqx/ubi_BinTree.c
index 15bdeb1d85..501f3eeca7 100644
--- a/source3/ubiqx/ubi_BinTree.c
+++ b/source3/ubiqx/ubi_BinTree.c
@@ -6,7 +6,7 @@
* Email: crh@ubiqx.mn.org
* -------------------------------------------------------------------------- **
*
- * This module implements simple binary trees.
+ * This module implements a simple binary tree.
*
* -------------------------------------------------------------------------- **
*
@@ -27,72 +27,69 @@
* -------------------------------------------------------------------------- **
*
* Log: ubi_BinTree.c,v
- * Revision 3.0 1997/12/08 06:49:11 crh
- * This is a new major revision level for all ubiqx binary tree modules.
- * In previous releases, the ubi_trNode structure looked like this:
+ * 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'.
*
- * typedef struct ubi_btNodeStruct
- * {
- * struct ubi_btNodeStruct *Link[3];
- * signed char gender;
- * } ubi_btNode;
+ * 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().
*
- * As a result, the pointers were indexed as
+ * 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.
*
- * Link[0] == Left Child
- * Link[1] == Parent
- * Link[2] == Right Child
+ * 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:
*
- * With this release, the node structure changes to:
+ * 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.
*
- * typedef struct ubi_btNodeStruct
- * {
- * struct ubi_btNodeStruct *leftlink
- * struct ubi_btNodeStruct *Link[2];
- * signed char gender;
- * } ubi_btNode;
+ * 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.
*
- * The leftlink field is used as a place holder, and the pointers are now
- * index as
- *
- * Link[-1] == Left Child (aka. leftlink)
- * Link[ 0] == Parent
- * Link[ 1] == Right Child
- *
- * which is much nicer. Doing things this way removes the need to shift
- * values between the two numbering schemes, thus removing one macro,
- * simplifying another, and getting rid of a whole bunch of increment &
- * decrement operations.
- *
- * Revision 2; 1995/02/27 - 1997/12/07 included:
- * - The addition of the ModuleID static string and ubi_ModuleID() function.
- * - The addition of the public functions FirstOf() and LastOf(). These
- * functions are used with trees that allow duplicate keys.
- * - The addition of the ubi_btLeafNode() function.
- * - A rewrite of the Locate() function.
- * - A change to the parameter list in function ubi_btInitTree().
- * - Bugfixes.
- *
- * Revision 1; 93/10/15 - 95/02/27:
- * Revision 1 introduced a set of #define's that provide a single API to all
- * of the existing tree modules. Each of these modules has a different name
- * prefix, as follows:
+ * 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
*
- * Only those portions of the base module (ubi_BinTree) that are superceeded
- * in the descendant module have new names. For example, the AVL node
- * structure in ubi_AVLtree.h is named "ubi_avlNode", but the root structure
- * is still "ubi_btRoot". Using SplayTree, the locate function is called
- * "ubi_sptLocate", but the next and previous functions remained "ubi_btNext"
- * and "ubi_btPrev".
+ * 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 is confusing.
+ * 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 added a set of defined names that get redefined in any of the
+ * 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
@@ -104,8 +101,7 @@
* 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, or if you plan to use two or more specific tree types
- * in the same piece of code. CRH
+ * red/black trees. CRH
*
* V0.0 - June, 1991 - Written by Christopher R. Hertel (CRH).
*
@@ -120,8 +116,8 @@
*/
static char ModuleID[] = "ubi_BinTree\n\
-\tRevision: 3.0\n\
-\tDate: 1997/12/08 06:49:11\n\
+\tRevision: 2.5\n\
+\tDate: 1997/12/23 03:56:29\n\
\tAuthor: crh\n";
/* ========================================================================== **
@@ -134,7 +130,7 @@ static ubi_btNodePtr qFind( ubi_btCompFunc cmp,
/* ------------------------------------------------------------------------ **
* This function performs a non-recursive search of a tree for a node
* matching a specific key. It is called "qFind()" because it is
- * (probably a little bit) faster that TreeFind (below).
+ * faster that TreeFind (below).
*
* Input:
* cmp - a pointer to the tree's comparison function.
@@ -153,9 +149,9 @@ static ubi_btNodePtr qFind( ubi_btCompFunc cmp,
* ------------------------------------------------------------------------ **
*/
{
- signed char tmp;
+ int tmp;
- while( p && (( tmp = ubi_trNormalize((*cmp)(FindMe, p)) ) != ubi_trEQUAL) )
+ while( p && (( tmp = ubi_trAbNormal((*cmp)(FindMe, p)) ) != ubi_trEQUAL) )
p = p->Link[tmp];
return( p );
@@ -164,7 +160,7 @@ static ubi_btNodePtr qFind( ubi_btCompFunc cmp,
static ubi_btNodePtr TreeFind( ubi_btItemPtr findme,
ubi_btNodePtr p,
ubi_btNodePtr *parentp,
- signed char *gender,
+ char *gender,
ubi_btCompFunc CmpFunc )
/* ------------------------------------------------------------------------ **
* TreeFind() searches a tree for a given value (findme). It will return a
@@ -195,16 +191,15 @@ static ubi_btNodePtr TreeFind( ubi_btItemPtr findme,
{
register ubi_btNodePtr tmp_p = p;
ubi_btNodePtr tmp_pp = NULL;
- signed char tmp_gender = ubi_trEQUAL;
- signed char tmp_cmp;
+ int tmp_gender = ubi_trEQUAL;
+ int tmp_cmp;
while( tmp_p
- && (ubi_trEQUAL != (tmp_cmp = ubi_trNormalize((*CmpFunc)(findme, tmp_p))))
- )
+ && (ubi_trEQUAL != (tmp_cmp = ubi_trAbNormal((*CmpFunc)(findme, tmp_p)))) )
{
- tmp_pp = tmp_p; /* Keep track of previous node. */
- tmp_gender = tmp_cmp; /* Keep track of sex of child. */
- tmp_p = tmp_p->Link[tmp_cmp]; /* Go to child. */
+ tmp_pp = tmp_p; /* Keep track of previous node. */
+ tmp_gender = 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;
@@ -214,7 +209,7 @@ static ubi_btNodePtr TreeFind( ubi_btItemPtr findme,
static void ReplaceNode( ubi_btNodePtr *parent,
ubi_btNodePtr oldnode,
ubi_btNodePtr newnode )
- /* ------------------------------------------------------------------------ **
+ /* ------------------------------------------------------------------ *
* Remove node oldnode from the tree, replacing it with node newnode.
*
* Input:
@@ -227,8 +222,12 @@ static void ReplaceNode( ubi_btNodePtr *parent,
* 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;
@@ -236,17 +235,12 @@ static void ReplaceNode( ubi_btNodePtr *parent,
for( i = 0; i < btNodeSize; i++ ) /* Copy node internals to new node. */
((unsigned char *)newnode)[i] = ((unsigned char *)oldnode)[i];
-
- /* Old node's parent points to new child. */
- (*parent) = newnode;
-
+ (*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_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,
@@ -274,21 +268,21 @@ static void SwapNodes( ubi_btRootPtr RootPtr,
/* Replace Node 1 with the dummy, thus removing Node1 from the tree. */
if( Node1->Link[ubi_trPARENT] )
- Parent = &((Node1->Link[ubi_trPARENT])->Link[Node1->gender]);
+ 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( Node2->Link[ubi_trPARENT] )
- Parent = &((Node2->Link[ubi_trPARENT])->Link[Node2->gender]);
+ 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( dummy_p->Link[ubi_trPARENT] )
- Parent = &((dummy_p->Link[ubi_trPARENT])->Link[dummy_p->gender]);
+ Parent = &((dummy_p->Link[ubi_trPARENT])->Link[(int)(dummy_p->gender)]);
else
Parent = &(RootPtr->root);
ReplaceNode( Parent, dummy_p, Node2 );
@@ -299,7 +293,7 @@ static void SwapNodes( ubi_btRootPtr RootPtr,
*/
static ubi_btNodePtr SubSlide( register ubi_btNodePtr P,
- register signed char whichway )
+ register int whichway )
/* ------------------------------------------------------------------------ **
* Slide down the side of a subtree.
*
@@ -327,7 +321,7 @@ static ubi_btNodePtr SubSlide( register ubi_btNodePtr P,
} /* SubSlide */
static ubi_btNodePtr Neighbor( register ubi_btNodePtr P,
- register signed char whichway )
+ register int whichway )
/* ------------------------------------------------------------------------ **
* Given starting point p, return the (key order) next or preceeding node
* in the tree.
@@ -346,7 +340,7 @@ static ubi_btNodePtr Neighbor( register ubi_btNodePtr P,
if( P )
{
if( P->Link[ whichway ] )
- return( SubSlide( P->Link[ whichway ], ubi_trRevWay(whichway) ) );
+ return( SubSlide( P->Link[ whichway ], (char)ubi_trRevWay(whichway) ) );
else
while( P->Link[ ubi_trPARENT ] )
{
@@ -362,7 +356,7 @@ static ubi_btNodePtr Neighbor( register ubi_btNodePtr P,
static ubi_btNodePtr Border( ubi_btRootPtr RootPtr,
ubi_btItemPtr FindMe,
ubi_btNodePtr p,
- signed char whichway )
+ 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.
@@ -401,7 +395,7 @@ static ubi_btNodePtr Border( ubi_btRootPtr RootPtr,
* subtree that contains all of the matching nodes.
*/
q = p->Link[ubi_trPARENT];
- while( q && (ubi_trEQUAL == ubi_trNormalize( (*(RootPtr->cmp))(FindMe, q) )) )
+ while( q && (ubi_trEQUAL == ubi_trAbNormal( (*(RootPtr->cmp))(FindMe, q) )) )
{
p = q;
q = p->Link[ubi_trPARENT];
@@ -411,7 +405,8 @@ static ubi_btNodePtr Border( ubi_btRootPtr RootPtr,
q = p->Link[whichway];
while( q )
{
- if( q = qFind( RootPtr->cmp, FindMe, q ) )
+ q = qFind( RootPtr->cmp, FindMe, q );
+ if( q )
{
p = q;
q = p->Link[whichway];
@@ -431,15 +426,15 @@ long ubi_btSgn( register long x )
*
* Input: x - a signed long integer value.
*
- * Output: -1, 0, or 1 representing the "sign" of x as follows:
+ * 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: {ubi_trLEFT, ubi_trPARENT, ubi_trEQUAL}. It is
- * incorporated into the ubi_trNormalize() conversion macro.
+ * 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!
*
* ------------------------------------------------------------------------ **
*/
@@ -553,7 +548,7 @@ ubi_trBool ubi_btInsert( ubi_btRootPtr RootPtr,
{
ubi_btNodePtr OtherP,
parent = NULL;
- signed char tmp;
+ char tmp;
if( !(OldNode) ) /* If they didn't give us a pointer, supply our own. */
OldNode = &OtherP;
@@ -570,7 +565,7 @@ ubi_trBool ubi_btInsert( ubi_btRootPtr RootPtr,
RootPtr->root = NewNode;
else
{
- parent->Link[tmp] = NewNode;
+ parent->Link[(int)tmp] = NewNode;
NewNode->Link[ubi_trPARENT] = parent;
NewNode->gender = tmp;
}
@@ -593,11 +588,11 @@ ubi_trBool ubi_btInsert( ubi_btRootPtr RootPtr,
parent = q;
if( tmp == ubi_trEQUAL )
tmp = ubi_trRIGHT;
- q = q->Link[tmp];
+ q = q->Link[(int)tmp];
if ( q )
- tmp = ubi_trNormalize( (*(RootPtr->cmp))(ItemPtr, q) );
+ tmp = ubi_trAbNormal( (*(RootPtr->cmp))(ItemPtr, q) );
}
- parent->Link[tmp] = NewNode;
+ parent->Link[(int)tmp] = NewNode;
NewNode->Link[ubi_trPARENT] = parent;
NewNode->gender = tmp;
(RootPtr->count)++;
@@ -613,7 +608,8 @@ ubi_trBool ubi_btInsert( ubi_btRootPtr RootPtr,
if (!(parent))
ReplaceNode( &(RootPtr->root), *OldNode, NewNode );
else
- ReplaceNode( &(parent->Link[(*OldNode)->gender]), *OldNode, NewNode );
+ ReplaceNode( &(parent->Link[(int)((*OldNode)->gender)]),
+ *OldNode, NewNode );
return( ubi_trTRUE );
}
@@ -639,7 +635,7 @@ ubi_btNodePtr ubi_btRemove( ubi_btRootPtr RootPtr,
{
ubi_btNodePtr p,
*parentp;
- signed char tmp;
+ 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
@@ -653,18 +649,18 @@ ubi_btNodePtr ubi_btRemove( ubi_btRootPtr RootPtr,
* a pointer to the parent pointer, whatever it is.
*/
if (DeadNode->Link[ubi_trPARENT])
- parentp = &((DeadNode->Link[ubi_trPARENT])->Link[DeadNode->gender]);
+ parentp = &((DeadNode->Link[ubi_trPARENT])->Link[(int)(DeadNode->gender)]);
else
parentp = &( RootPtr->root );
/* Now link the parent to the only grand-child and patch up the gender. */
- tmp = ((DeadNode->Link[ubi_trLEFT]) ? ubi_trLEFT : ubi_trRIGHT);
+ tmp = ((DeadNode->Link[ubi_trLEFT])?ubi_trLEFT:ubi_trRIGHT);
p = (DeadNode->Link[tmp]);
if( p )
{
p->Link[ubi_trPARENT] = DeadNode->Link[ubi_trPARENT];
- p->gender = DeadNode->gender;
+ p->gender = DeadNode->gender;
}
(*parentp) = p;
@@ -727,7 +723,7 @@ ubi_btNodePtr ubi_btLocate( ubi_btRootPtr RootPtr,
{
register ubi_btNodePtr p;
ubi_btNodePtr parent;
- signed char whichkid;
+ char whichkid;
/* Start by searching for a matching node. */
p = TreeFind( FindMe,
@@ -746,9 +742,10 @@ ubi_btNodePtr ubi_btLocate( ubi_btRootPtr RootPtr,
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 );
}
- p = Border( RootPtr, FindMe, p, ubi_trLEFT );
- return( p );
}
/* Else, no match. */
@@ -761,7 +758,7 @@ ubi_btNodePtr ubi_btLocate( ubi_btRootPtr RootPtr,
* Remaining possibilities are LT and GT (including LE & GE).
*/
if( (ubi_trLT == CompOp) || (ubi_trLE == CompOp) )
- return( (ubi_trLEFT == whichkid) ? Neighbor( parent, whichkid ) : parent );
+ return( (ubi_trLEFT == whichkid) ? Neighbor( parent, whichkid ) : parent );
else
return( (ubi_trRIGHT == whichkid) ? Neighbor( parent, whichkid ) : parent );
} /* ubi_btLocate */
@@ -866,7 +863,7 @@ ubi_btNodePtr ubi_btFirstOf( ubi_btRootPtr RootPtr,
*/
{
/* If our starting point is invalid, return NULL. */
- if( !p || ubi_trNormalize( (*(RootPtr->cmp))( MatchMe, p ) != ubi_trEQUAL ) )
+ if( !p || ubi_trAbNormal( (*(RootPtr->cmp))( MatchMe, p ) != ubi_trEQUAL ) )
return( NULL );
return( Border( RootPtr, MatchMe, p, ubi_trLEFT ) );
} /* ubi_btFirstOf */
@@ -891,7 +888,7 @@ ubi_btNodePtr ubi_btLastOf( ubi_btRootPtr RootPtr,
*/
{
/* If our starting point is invalid, return NULL. */
- if( !p || ubi_trNormalize( (*(RootPtr->cmp))( MatchMe, p ) != ubi_trEQUAL ) )
+ if( !p || ubi_trAbNormal( (*(RootPtr->cmp))( MatchMe, p ) != ubi_trEQUAL ) )
return( NULL );
return( Border( RootPtr, MatchMe, p, ubi_trRIGHT ) );
} /* ubi_btLastOf */
@@ -990,8 +987,6 @@ ubi_btNodePtr ubi_btLeafNode( ubi_btNodePtr leader )
* 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.
- * + If using a splay tree, splaying the tree will tend to randomize
- * things a bit too. See ubi_SplayTree for more info.
*
* ------------------------------------------------------------------------ **
*/
@@ -1001,10 +996,8 @@ ubi_btNodePtr ubi_btLeafNode( ubi_btNodePtr leader )
while( NULL != leader )
{
- /* The next line is a weak attempt at randomizing. */
- whichway = ((int)leader & 0x0010) ? whichway : ubi_trRevWay(whichway);
follower = leader;
- leader = leader->Link[ whichway ];
+ leader = follower->Link[ whichway ];
if( NULL == leader )
{
whichway = ubi_trRevWay( whichway );
@@ -1043,4 +1036,5 @@ int ubi_btModuleID( int size, char *list[] )
return( 0 );
} /* ubi_btModuleID */
+
/* ========================================================================== */
diff --git a/source3/ubiqx/ubi_BinTree.h b/source3/ubiqx/ubi_BinTree.h
index d5032b58a2..4b918a4609 100644
--- a/source3/ubiqx/ubi_BinTree.h
+++ b/source3/ubiqx/ubi_BinTree.h
@@ -8,7 +8,7 @@
* Email: crh@ubiqx.mn.org
* -------------------------------------------------------------------------- **
*
- * This module implements simple binary trees.
+ * This module implements a simple binary tree.
*
* -------------------------------------------------------------------------- **
*
@@ -29,72 +29,69 @@
* -------------------------------------------------------------------------- **
*
* Log: ubi_BinTree.h,v
- * Revision 3.0 1997/12/08 06:49:15 crh
- * This is a new major revision level for all ubiqx binary tree modules.
- * In previous releases, the ubi_trNode structure looked like this:
- *
- * typedef struct ubi_btNodeStruct
- * {
- * struct ubi_btNodeStruct *Link[3];
- * signed char gender;
- * } ubi_btNode;
- *
- * As a result, the pointers were indexed as
- *
- * Link[0] == Left Child
- * Link[1] == Parent
- * Link[2] == Right Child
- *
- * With this release, the node structure changes to:
- *
- * typedef struct ubi_btNodeStruct
- * {
- * struct ubi_btNodeStruct *leftlink
- * struct ubi_btNodeStruct *Link[2];
- * signed char gender;
- * } ubi_btNode;
- *
- * The leftlink field is used as a place holder, and the pointers are now
- * index as
- *
- * Link[-1] == Left Child (aka. leftlink)
- * Link[ 0] == Parent
- * Link[ 1] == Right Child
- *
- * which is much nicer. Doing things this way removes the need to shift
- * values between the two numbering schemes, thus removing one macro,
- * simplifying another, and getting rid of a whole bunch of increment &
- * decrement operations.
- *
- * Revision 2; 1995/02/27 - 1997/12/07 included:
- * - The addition of the ModuleID static string and ubi_ModuleID() function.
- * - The addition of the public functions FirstOf() and LastOf(). These
- * functions are used with trees that allow duplicate keys.
- * - The addition of the ubi_btLeafNode() function.
- * - A rewrite of the Locate() function.
- * - A change to the parameter list in function ubi_btInitTree().
- * - Bugfixes.
- *
- * Revision 1; 93/10/15 - 95/02/27:
- * Revision 1 introduced a set of #define's that provide a single API to all
- * of the existing tree modules. Each of these modules has a different name
- * prefix, as follows:
+ * Revision 2.5 1997/12/23 03:59:21 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 04:11:14 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
*
- * Only those portions of the base module (ubi_BinTree) that are superceeded
- * in the descendant module have new names. For example, the AVL node
- * structure in ubi_AVLtree.h is named "ubi_avlNode", but the root structure
- * is still "ubi_btRoot". Using SplayTree, the locate function is called
- * "ubi_sptLocate", but the next and previous functions remained "ubi_btNext"
- * and "ubi_btPrev".
+ * 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 is confusing.
+ * 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 added a set of defined names that get redefined in any of the
+ * 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
@@ -106,8 +103,7 @@
* 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, or if you plan to use two or more specific tree types
- * in the same piece of code. CRH
+ * red/black trees. CRH
*
* V0.0 - June, 1991 - Written by Christopher R. Hertel (CRH).
*
@@ -115,7 +111,7 @@
*/
/* -------------------------------------------------------------------------- **
- * Constants...
+ * Macros and constants.
*
* General purpose:
* ubi_trTRUE - Boolean TRUE.
@@ -125,16 +121,16 @@
* 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 allows duplicates, the overwrite
- * flag is ignored.
+ * 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; pointer to the left child,
- * pointer to the right child, and a pointer back to the parent node.)
- * ubi_trLEFT - Left child pointer.
- * ubi_trPARENT - Parent pointer.
- * ubi_trRIGHT - Right child pointer.
- * ubi_trEQUAL - Synonym for PARENT.
+ * 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.)
+ * ubi_trLEFT - Left child pointer.
+ * ubi_trPARENT - Parent pointer.
+ * ubi_trRIGHT - Right child pointer.
+ * ubi_trEQUAL - 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
@@ -147,6 +143,7 @@
* 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
@@ -156,13 +153,12 @@
#define ubi_trDUPKEY 0x02 /* Turn on allow duplicate keys */
/* Pointer array index constants... */
-#define ubi_trLEFT -1
-#define ubi_trPARENT 0
-#define ubi_trRIGHT 1
-#define ubi_trEQUAL ubi_trPARENT
+#define ubi_trLEFT 0x00
+#define ubi_trPARENT 0x01
+#define ubi_trRIGHT 0x02
+#define ubi_trEQUAL ubi_trPARENT
-typedef enum
- {
+typedef enum {
ubi_trLT = 1,
ubi_trLE,
ubi_trEQ,
@@ -171,57 +167,59 @@ typedef enum
} ubi_trCompOps;
/* -------------------------------------------------------------------------- **
- * Macros...
- * ubi_trNormalize() - "Normalize" a value with respect to ubi_trLEFT,
- * ubi_trRIGHT, and ubi_trPARENT. This macro calls
- * ubi_btSgn() to convert the input to -1, 0, or 1.
- * The resultant value is returned as a signed char.
- *
- * ubi_trRevWay() - converts ubi_trLEFT to ubi_trRIGHT and vice versa.
- * ubi_trPARENT (ubi_trEQUAL) is left as is.
- *
- * ubi_trDups_OK() - returns TRUE if the tree allows duplicates.
- *
- * ubi_trOvwt_OK() - returns TRUE if the overwrite flag is on. Note
- * that overwrites will not occur in a tree that
- * allows duplicates.
+ * 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 ubi_trNormalize(W) ((char)( (W) - ubi_trEQUAL ))
+#define ubi_trAbNormal(W) ((char)( ((char)ubi_btSgn( W )) + ubi_trEQUAL ))
+#define ubi_trRevWay(W) ((char)( ubi_trEQUAL - ((W) - ubi_trEQUAL) ))
-#define ubi_trNormalize(W) ((signed char)ubi_btSgn(W))
-#define ubi_trRevWay(W) (-(W))
-
+/* -------------------------------------------------------------------------- **
+ * These macros allow us to quickly read the values of the OVERWRITE and
+ * DUPlicate KEY bits of the tree root flags field.
+ * -------------------------------------------------------------------------- **
+ */
#define ubi_trDups_OK(A) \
- ((ubi_trDUPKEY & ((A)->flags)) ? (ubi_trTRUE) : (ubi_trFALSE))
+ ((ubi_trDUPKEY & ((A)->flags))?(ubi_trTRUE):(ubi_trFALSE))
#define ubi_trOvwt_OK(A) \
- ((ubi_trOVERWRITE & ((A)->flags))? (ubi_trTRUE) : (ubi_trFALSE))
-
+ ((ubi_trOVERWRITE & ((A)->flags))?(ubi_trTRUE):(ubi_trFALSE))
/* -------------------------------------------------------------------------- **
* Typedefs...
*
- * ubi_trBool - Your typcial true or false...
+ * ubi_trBool - Your typcial true or false...
*
- * ubi_btItemPtr - The Item Pointer is a generic pointer. It is used to
- * indicate a key for which to search within the tree.
- * The ubi_trFind(), ubi_trLocate(), and ubi_trInsert()
- * functions all perform searches.
+ * 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; /* Our own name for "boolean". */
+typedef unsigned char ubi_trBool;
-typedef void *ubi_btItemPtr; /* A pointer to (key) data within a node. */
+typedef void *ubi_btItemPtr; /* A pointer to data within a node. */
-/* -------------------------------------------------------------------------- **
- * Typedefs continued...
- *
+/* ------------------------------------------------------------------------- **
* 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:
- * leftlink - pointer to the left child of the node. This field will
- * be accessed as Link[-1].
* 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
@@ -232,22 +230,18 @@ typedef void *ubi_btItemPtr; /* A pointer to (key) data within a node. */
* 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 *leftlink; /* Will be accessed as Link[-1]. */
- struct ubi_btNodeStruct *Link[2]; /* Parent & Right links. */
- signed char gender; /* Indicates Left/Right of 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. */
-/* -------------------------------------------------------------------------- **
- * Typedefs continued...
- *
- * The next three typedefs define standard function types used by the binary
- * tree management routines. In particular:
+/* ------------------------------------------------------------------------- **
+ * 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
@@ -267,6 +261,7 @@ typedef ubi_btNode *ubi_btNodePtr; /* Pointer to an ubi_btNode structure. */
* 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 );
@@ -276,10 +271,8 @@ typedef void (*ubi_btActionRtn)( ubi_btNodePtr, void * );
typedef void (*ubi_btKillNodeRtn)( ubi_btNodePtr );
/* -------------------------------------------------------------------------- **
- * Typedefs continued...
- *
- * Tree Root Structure: This structure gives us a convenient handle for
- * accessing whole AVL trees. The fields are:
+ * 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
@@ -293,15 +286,13 @@ typedef void (*ubi_btKillNodeRtn)( ubi_btNodePtr );
* (bit 0x02) allowed to contain nodes with duplicate keys.
*
* NOTE: ubi_trInsert() tests ubi_trDUPKEY before ubi_trOVERWRITE.
- * If duplicate keys are allowed, then no entry will be
- * overwritten.
*
- * All of these values are set when you initialize the root structure by
- * calling ubi_trInitTree().
+ * All of these values are set when you initialize the root structure by
+ * calling ubi_trInitTree().
+ * -------------------------------------------------------------------------- **
*/
-typedef struct
- {
+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 */
@@ -321,15 +312,15 @@ long ubi_btSgn( long x );
*
* Input: x - a signed long integer value.
*
- * Output: -1, 0, or 1 representing the "sign" of x as follows:
+ * Output: the "sign" of x, represented as follows:
* -1 == negative
* 0 == zero (no sign)
* 1 == positive
*
- * Notes: This utility is provided in order to facilitate the conversion
- * of C comparison function return values into BinTree direction
- * values: {ubi_trLEFT, ubi_trPARENT, ubi_trEQUAL}. It is
- * incorporated into the Normalize() conversion macro.
+ * 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!
*
* ------------------------------------------------------------------------ **
*/
@@ -344,9 +335,9 @@ ubi_btNodePtr ubi_btInitNode( ubi_btNodePtr NodePtr );
* ------------------------------------------------------------------------ **
*/
-ubi_btRootPtr ubi_btInitTree( ubi_btRootPtr RootPtr,
- ubi_btCompFunc CompFunc,
- unsigned char Flags );
+ubi_btRootPtr ubi_btInitTree( ubi_btRootPtr RootPtr,
+ ubi_btCompFunc CompFunc,
+ unsigned char Flags );
/* ------------------------------------------------------------------------ **
* Initialize the fields of a Tree Root header structure.
*
@@ -648,8 +639,6 @@ ubi_btNodePtr ubi_btLeafNode( ubi_btNodePtr leader );
* 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.
- * + If using a splay tree, splaying the tree will tend to randomize
- * things a bit too. See ubi_SplayTree for more info.
*
* ------------------------------------------------------------------------ **
*/
diff --git a/source3/ubiqx/ubi_SplayTree.c b/source3/ubiqx/ubi_SplayTree.c
index fb4cc9f7c8..799996b6cc 100644
--- a/source3/ubiqx/ubi_SplayTree.c
+++ b/source3/ubiqx/ubi_SplayTree.c
@@ -35,16 +35,78 @@
* -------------------------------------------------------------------------- **
*
* Log: ubi_SplayTree.c,v
- * Revision 3.0 1997/12/08 05:32:28 crh
- * This is a new major revision level because of a redesign of the handling
- * of the pointers in the ubi_trNode structure. See ubi_BinTree for more
- * info.
+ * Revision 2.6 1997/12/23 04:01:12 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; 1995/02/27 - 1997/12/07:
- * Major changes: added the function ubi_sptSplay().
+ * Revision 2.5 1997/07/26 04:15:42 crh
+ * + Cleaned up a few minor syntax annoyances that gcc discovered for me.
+ * + Changed ubi_TRUE and ubi_FALSE to ubi_trTRUE and ubi_trFALSE.
*
- * Revision 1; 93/10/15 - 95/02/27:
- * Added the ubi_tr defines. See ubi_BinTree.h for more info.
+ * Revision 2.4 1997/06/03 04:42:21 crh
+ * Changed TRUE and FALSE to ubi_TRUE and ubi_FALSE to avoid causing
+ * problems.
+ *
+ * Revision 2.3 1995/10/03 22:19:07 CRH
+ * Ubisized!
+ * Also, added the function ubi_sptSplay().
+ *
+ * Revision 2.1 95/03/09 23:54:42 CRH
+ * Added the ModuleID static string and function. These modules are now
+ * self-identifying.
+ *
+ * Revision 2.0 95/02/27 22:34:46 CRH
+ * This module was updated to match the interface changes made to the
+ * ubi_BinTree module. In particular, the interface to the Locate() function
+ * has changed. See ubi_BinTree for more information on changes and new
+ * functions.
+ *
+ * The revision number was also upped to match ubi_BinTree.
+ *
+ * Revision 1.1 93/10/18 20:35:16 CRH
+ * I removed the hard-coded logical device names from the include file
+ * specifications. CRH
+ *
+ * Revision 1.0 93/10/15 23:00:15 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
+ *
+ * Revision 0.1 93/04/25 22:03:32 CRH
+ * Simply changed the <exec/types.h> #include reference the .c file to
+ * use <stdlib.h> instead. The latter is portable, the former is not.
*
* Revision 0.0 93/04/21 23:05:52 CRH
* Initial version, written by Christopher R. Hertel.
@@ -61,8 +123,8 @@
*/
static char ModuleID[] = "ubi_SplayTree\n\
-\tRevision: 3.0\n\
-\tDate: 1997/12/08 05:32:28\n\
+\tRevision: 2.6\n\
+\tDate: 1997/12/23 04:01:12\n\
\tAuthor: crh\n";
@@ -87,18 +149,18 @@ static void Rotate( ubi_btNodePtr p )
{
ubi_btNodePtr parentp;
ubi_btNodePtr tmp;
- signed char way;
- signed char revway;
+ char way;
+ char revway;
parentp = p->Link[ubi_trPARENT]; /* Find parent. */
if( parentp ) /* If no parent, then we're already the root. */
{
- way = p->gender;
- revway = ubi_trRevWay(way);
- tmp = p->Link[revway];
+ way = p->gender;
+ revway = ubi_trRevWay(way);
+ tmp = p->Link[(int)revway];
- parentp->Link[way] = tmp;
+ parentp->Link[(int)way] = tmp;
if( tmp )
{
tmp->Link[ubi_trPARENT] = parentp;
@@ -109,11 +171,11 @@ static void Rotate( ubi_btNodePtr p )
p->Link[ubi_trPARENT] = tmp;
p->gender = parentp->gender;
if( tmp )
- tmp->Link[p->gender] = p;
+ tmp->Link[(int)(p->gender)] = p;
parentp->Link[ubi_trPARENT] = p;
parentp->gender = revway;
- p->Link[revway] = parentp;
+ p->Link[(int)revway] = parentp;
}
} /* Rotate */
@@ -141,7 +203,7 @@ static ubi_btNodePtr Splay( ubi_btNodePtr SplayWithMe )
Rotate( SplayWithMe );
}
Rotate( SplayWithMe ); /* Zig */
- }
+ } /* while */
return( SplayWithMe );
} /* Splay */
@@ -238,9 +300,9 @@ ubi_btNodePtr ubi_sptRemove( ubi_btRootPtr RootPtr, ubi_btNodePtr DeadNode )
ubi_btNodePtr q = DeadNode->Link[ubi_trRIGHT];
p->Link[ubi_trPARENT] = NULL; /* Left subtree node becomes root.*/
- p->gender = ubi_trPARENT;
- p = ubi_btLast( p ); /* Find rightmost left tree node..*/
- p->Link[ubi_trRIGHT] = q; /* ...attach right tree. */
+ p->gender = ubi_trPARENT;
+ p = ubi_btLast( p ); /* Find rightmost left node... */
+ p->Link[ubi_trRIGHT] = q; /* ...attach right tree. */
if( q )
q->Link[ubi_trPARENT] = p;
RootPtr->root = Splay( p ); /* Resplay at p. */
@@ -368,7 +430,7 @@ void ubi_sptSplay( ubi_btRootPtr RootPtr,
* Splaying the tree will not damage it (assuming that I've done
* *my* job), but there is overhead involved. I don't recommend
* that you use this function unless you understand the underlying
- * Splay Tree.
+ * Splay Tree principles involved.
* ------------------------------------------------------------------------ **
*/
{
diff --git a/source3/ubiqx/ubi_SplayTree.h b/source3/ubiqx/ubi_SplayTree.h
index 089fdc9d68..d45c32fce8 100644
--- a/source3/ubiqx/ubi_SplayTree.h
+++ b/source3/ubiqx/ubi_SplayTree.h
@@ -37,16 +37,71 @@
* -------------------------------------------------------------------------- **
*
* Log: ubi_SplayTree.h,v
- * Revision 3.0 1997/12/08 05:32:35 crh
- * This is a new major revision level because of a redesign of the handling
- * of the pointers in the ubi_trNode structure. See ubi_BinTree for more
- * info.
+ * Revision 2.6 1997/12/23 04:02:20 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; 1995/02/27 - 1997/12/07:
- * Major changes: added the function ubi_sptSplay().
+ * Revision 2.5 1997/07/26 04:15:46 crh
+ * + Cleaned up a few minor syntax annoyances that gcc discovered for me.
+ * + Changed ubi_TRUE and ubi_FALSE to ubi_trTRUE and ubi_trFALSE.
*
- * Revision 1; 93/10/15 - 95/02/27:
- * Added the ubi_tr defines. See ubi_BinTree.h for more info.
+ * Revision 2.4 1997/06/03 05:22:56 crh
+ * Changed TRUE and FALSE to ubi_TRUE and ubi_FALSE to avoid causing
+ * problems.
+ *
+ * Revision 2.3 1995/10/03 22:19:37 CRH
+ * Ubisized!
+ * Also, added the function ubi_sptSplay().
+ *
+ * Revision 2.1 95/03/09 23:55:04 CRH
+ * Added the ModuleID static string and function. These modules are now
+ * self-identifying.
+ *
+ * Revision 2.0 95/02/27 22:34:55 CRH
+ * This module was updated to match the interface changes made to the
+ * ubi_BinTree module. In particular, the interface to the Locate() function
+ * has changed. See ubi_BinTree for more information on changes and new
+ * functions.
+ *
+ * The revision number was also upped to match ubi_BinTree.
+ *
+ *
+ * Revision 1.0 93/10/15 22:59:36 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
*
* Revision 0.0 93/04/21 23:07:13 CRH
* Initial version, written by Christopher R. Hertel.
@@ -217,7 +272,7 @@ void ubi_sptSplay( ubi_btRootPtr RootPtr,
* Splaying the tree will not damage it (assuming that I've done
* *my* job), but there is overhead involved. I don't recommend
* that you use this function unless you understand the underlying
- * Splay Tree.
+ * Splay Tree principles involved.
* ------------------------------------------------------------------------ **
*/