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fis-gtm/sr_port/lv_tree.c

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/****************************************************************
* *
* Copyright 2011, 2012 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "gtm_string.h"
#include <stddef.h> /* for OFFSETOF macro used in the IS_OFFSET_AND_SIZE_MATCH macro */
#include "collseq.h"
#include "subscript.h"
#include "lv_tree.h"
#include "gtm_stdio.h"
#include "min_max.h"
#include "lv_val.h"
#include "numcmp.h"
#include "arit.h"
#include "promodemo.h" /* for "promote" & "demote" prototype */
#include "gtmio.h"
#include "have_crit.h"
#define LV_TREE_INIT_ALLOC 4
#define LV_TREENODE_INIT_ALLOC 16
#define LV_TREESUBSCR_INIT_ALLOC 16
/* the below assumes TREE_LEFT_HEAVY is 0, TREE_RIGHT_HEAVY is 1 and TREE_BALANCED is 2 */
LITDEF int tree_balance_invert[] = {TREE_RIGHT_HEAVY, TREE_LEFT_HEAVY, TREE_BALANCED};
LITREF mval literal_null;
LITREF int4 ten_pwr[NUM_DEC_DG_1L+1];
STATICFNDCL void lvAvlTreeNodeFltConv(lvTreeNodeNum *fltNode);
STATICFNDCL lvTreeNode *lvAvlTreeSingleRotation(lvTreeNode *rebalanceNode, lvTreeNode *anchorNode, int4 balanceFactor);
STATICFNDCL lvTreeNode *lvAvlTreeDoubleRotation(lvTreeNode *rebalanceNode, lvTreeNode *anchorNode, int4 balanceFactor);
STATICFNDCL boolean_t lvAvlTreeLookupKeyCheck(treeKeySubscr *key);
STATICFNDCL int lvAvlTreeNodeHeight(lvTreeNode *node);
STATICFNDCL boolean_t lvAvlTreeNodeIsWellFormed(lvTree *lvt, lvTreeNode *node);
STATICFNDEF void lvAvlTreeNodeFltConv(lvTreeNodeNum *fltNode)
{
int int_m1, int_exp;
const int4 *pwr;
DEBUG_ONLY(int key_mvtype;)
DEBUG_ONLY(key_mvtype = fltNode->key_mvtype;)
assert(MV_INT & key_mvtype);
assert(!fltNode->key_flags.key_bits.key_iconv);
int_m1 = fltNode->key_m0;
if (int_m1)
{
/* The following logic is very similar to that in promodemo.c (promote function).
* That operates on mvals whereas this does not hence the duplication inspite of similar logic.
*/
if (0 < int_m1)
fltNode->key_flags.key_bits.key_sgn = 0;
else
{
fltNode->key_flags.key_bits.key_sgn = 1;
int_m1 = -int_m1;
}
int_exp = 0;
pwr = &ten_pwr[0];
while (int_m1 >= *pwr)
{
int_exp++;
pwr++;
assert(pwr < ARRAYTOP(ten_pwr));
}
fltNode->key_m1 = int_m1 * ten_pwr[NUM_DEC_DG_1L - int_exp] ;
int_exp += EXP_INT_UNDERF;
fltNode->key_flags.key_bits.key_e = int_exp;
} else
fltNode->key_flags.key_bits.key_e = 0; /* integer 0 will have exponent 0 even after float promotion */
fltNode->key_flags.key_bits.key_iconv = TRUE;
return;
}
/* All the below comparison macros & functions return
* = 0 if equal;
* < 0 if key of aSUBSCR < key of bNODE;
* > 0 if key of aSUBSCR > key of bNODE
* The 3 LV_AVL_TREE_*KEY_CMP macros below have very similar (yet not completely identical) code.
* They are kept separate because this is frequently used code and we want to avoid if checks as much as possible.
* Having separate macros for each keytype lets us reduce the # of if checks we need inside the macro.
*/
#define LV_AVL_TREE_INTKEY_CMP(aSUBSCR, aSUBSCR_M1, bNODE, retVAL) \
{ \
int a_m1, b_mvtype, a_sgn, b_sgn, exp_diff, m1_diff, m0_diff, b_m0; \
lvTreeNodeNum *bNodeFlt; \
treeKeySubscr fltSubscr, *tmpASubscr; \
\
/* aSUBSCR is a number */ \
assert(TREE_KEY_SUBSCR_IS_CANONICAL((aSUBSCR)->mvtype)); \
assert(MVTYPE_IS_INT((aSUBSCR)->mvtype)); \
b_mvtype = (bNODE)->key_mvtype; \
assert(!TREE_KEY_SUBSCR_IS_CANONICAL(b_mvtype) \
|| (MVTYPE_IS_NUMERIC(b_mvtype) && !MVTYPE_IS_NUM_APPROX(b_mvtype))); \
assert(MVTYPE_IS_NUMERIC((aSUBSCR)->mvtype) && !MVTYPE_IS_NUM_APPROX((aSUBSCR)->mvtype)); \
assert((aSUBSCR_M1) == (aSUBSCR)->m[1]); \
if (MV_INT & b_mvtype) \
{ \
bNodeFlt = (lvTreeNodeNum *)(bNODE); \
(retVAL) = (aSUBSCR_M1) - bNodeFlt->key_m0; \
} else if (TREE_KEY_SUBSCR_IS_CANONICAL(b_mvtype)) \
{ /* Both aSUBSCR and bNODE are numbers */ \
b_mvtype &= MV_INT; \
/* aSUBSCR is MV_INT but bNODE is not. Promote aSubscr to float representation before comparing \
* it with bNODE. Cannot touch input mval since non-lv code expects MV_INT value to be stored in \
* integer format only (and not float format). So use a temporary mval for comparison. \
*/ \
fltSubscr.m[1] = (aSUBSCR_M1); \
tmpASubscr = &fltSubscr; \
promote(tmpASubscr); /* Note this modifies tmpASubscr->m[1] so no longer can use aSUBSCR_M1 below */ \
assert(tmpASubscr->e || !tmpASubscr->m[1]); \
bNodeFlt = (lvTreeNodeNum *)(bNODE); \
if (b_mvtype && !bNodeFlt->key_flags.key_bits.key_iconv) \
{ \
lvAvlTreeNodeFltConv(bNodeFlt); \
assert(bNodeFlt->key_flags.key_bits.key_iconv); \
} \
a_sgn = (0 == tmpASubscr->sgn) ? 1 : -1; /* 1 if positive, -1 if negative */ \
b_sgn = (0 == bNodeFlt->key_flags.key_bits.key_sgn) ? 1 : -1; \
/* Check sign. If different we are done right there */ \
if (a_sgn != b_sgn) \
(retVAL) = a_sgn; \
else \
{ /* Signs equal; compare exponents for magnitude and adjust sense depending on sign. */ \
exp_diff = tmpASubscr->e - bNodeFlt->key_flags.key_bits.key_e; \
if (exp_diff) \
(retVAL) = (exp_diff * a_sgn); \
else \
{ /* Signs and exponents equal; compare magnitudes. */ \
/* First, compare high-order 9 digits of magnitude. */ \
a_m1 = tmpASubscr->m[1]; \
m1_diff = a_m1 - bNodeFlt->key_m1; \
if (m1_diff) \
(retVAL) = (m1_diff * a_sgn); \
else \
{ /* High-order 9 digits equal; if not zero, compare low-order 9 digits. */ \
if (0 == a_m1) /* zero special case */ \
(retVAL) = 0; \
else \
{ \
b_m0 = (b_mvtype ? 0 : bNodeFlt->key_m0); \
m0_diff = tmpASubscr->m[0] - b_m0; \
if (m0_diff) \
(retVAL) = (m0_diff * a_sgn); \
else \
{ /* Signs, exponents, high-order & low-order magnitudes equal */ \
(retVAL) = 0; \
} \
} \
} \
} \
} \
} else \
(retVAL) = -1; /* aSubscr is a number, but bNODE is a string */ \
}
#define LV_AVL_TREE_NUMKEY_CMP(aSUBSCR, bNODE, retVAL) \
{ \
int b_mvtype, a_sgn, b_sgn, exp_diff, m1_diff, m0_diff, a_m1, b_m0; \
lvTreeNodeNum *bNodeFlt; \
\
/* aSUBSCR is a number */ \
assert(TREE_KEY_SUBSCR_IS_CANONICAL((aSUBSCR)->mvtype)); \
assert(!MVTYPE_IS_INT((aSUBSCR)->mvtype)); \
b_mvtype = (bNODE)->key_mvtype; \
assert(!TREE_KEY_SUBSCR_IS_CANONICAL(b_mvtype) \
|| (MVTYPE_IS_NUMERIC(b_mvtype) && !MVTYPE_IS_NUM_APPROX(b_mvtype))); \
assert(MVTYPE_IS_NUMERIC((aSUBSCR)->mvtype) && !MVTYPE_IS_NUM_APPROX((aSUBSCR)->mvtype)); \
if (TREE_KEY_SUBSCR_IS_CANONICAL(b_mvtype)) \
{ /* Both aSUBSCR and bNODE are numbers */ \
b_mvtype &= MV_INT; \
bNodeFlt = (lvTreeNodeNum *)(bNODE); \
if (b_mvtype && !bNodeFlt->key_flags.key_bits.key_iconv) \
{ \
lvAvlTreeNodeFltConv(bNodeFlt); \
assert(bNodeFlt->key_flags.key_bits.key_iconv); \
} \
a_sgn = (0 == (aSUBSCR)->sgn) ? 1 : -1; /* 1 if positive, -1 if negative */ \
b_sgn = (0 == bNodeFlt->key_flags.key_bits.key_sgn) ? 1 : -1; \
/* Check sign. If different we are done right there */ \
if (a_sgn != b_sgn) \
(retVAL) = a_sgn; \
else \
{ /* Signs equal; compare exponents for magnitude and adjust sense depending on sign. */ \
exp_diff = (aSUBSCR)->e - bNodeFlt->key_flags.key_bits.key_e; \
if (exp_diff) \
(retVAL) = (exp_diff * a_sgn); \
else \
{ /* Signs and exponents equal; compare magnitudes. */ \
/* First, compare high-order 9 digits of magnitude. */ \
a_m1 = (aSUBSCR)->m[1]; \
m1_diff = a_m1 - bNodeFlt->key_m1; \
if (m1_diff) \
(retVAL) = (m1_diff * a_sgn); \
else \
{ /* High-order 9 digits equal; if not zero, compare low-order 9 digits. */ \
if (0 == a_m1) /* zero special case */ \
(retVAL) = 0; \
else \
{ \
b_m0 = (b_mvtype ? 0 : bNodeFlt->key_m0); \
m0_diff = (aSUBSCR)->m[0] - b_m0; \
if (m0_diff) \
(retVAL) = (m0_diff * a_sgn); \
else \
{ /* Signs, exponents, high-order & low-order magnitudes equal */ \
(retVAL) = 0; \
} \
} \
} \
} \
} \
} else \
(retVAL) = -1; /* aSUBSCR is a number, but bNODE is a string */ \
}
#define LV_AVL_TREE_STRKEY_CMP(aSUBSCR, aSUBSCR_ADDR, aSUBSCR_LEN, bNODE, retVAL) \
{ \
/* aSUBSCR is a string */ \
assert(!TREE_KEY_SUBSCR_IS_CANONICAL((aSUBSCR)->mvtype)); \
assert(MVTYPE_IS_STRING((aSUBSCR)->mvtype)); \
if (TREE_KEY_SUBSCR_IS_CANONICAL((bNODE)->key_mvtype)) \
(retVAL) = 1; /* aSUBSCR is a string, but bNODE is a number */ \
else /* aSUBSCR and bNODE are both strings */ \
MEMVCMP(aSUBSCR_ADDR, aSUBSCR_LEN, (bNODE)->key_addr, (bNODE)->key_len, (retVAL)); \
}
#ifdef DEBUG
/* This function is currently DEBUG-only because no one is supposed to be calling it.
* Callers are usually performance sensitive and should therefore use the LV_AVL_TREE_NUMKEY_CMP
* or LV_AVL_TREE_STRKEY_CMP macros that this function in turn invokes.
*/
int lvAvlTreeKeySubscrCmp(treeKeySubscr *aSubscr, lvTreeNode *bNode)
{
int retVal, a_mvtype;
a_mvtype = aSubscr->mvtype;
if (TREE_KEY_SUBSCR_IS_CANONICAL(a_mvtype))
{
if (MVTYPE_IS_INT(a_mvtype))
{
LV_AVL_TREE_INTKEY_CMP(aSubscr, aSubscr->m[1], bNode, retVal);
} else
LV_AVL_TREE_NUMKEY_CMP(aSubscr, bNode, retVal);
} else
LV_AVL_TREE_STRKEY_CMP(aSubscr, aSubscr->str.addr, aSubscr->str.len, bNode, retVal);
return retVal;
}
/* This function is currently coded not as efficiently as it needs to be because it is only invoked by dbg code.
* Hence the definition inside a #ifdef DEBUG. If this change and pro code needs it, the below code needs to be revisited.
*/
int lvAvlTreeNodeSubscrCmp(lvTreeNode *aNode, lvTreeNode *bNode)
{
int a_mvtype, b_mvtype, retVal;
int a_sgn, b_sgn, exp_diff, m1_diff, m0_diff, a_m1, b_m1, a_m0, b_m0;
lvTreeNodeNum *aNodeFlt, *bNodeFlt;
a_mvtype = aNode->key_mvtype;
b_mvtype = bNode->key_mvtype;
if (TREE_KEY_SUBSCR_IS_CANONICAL(a_mvtype))
{ /* aSubscr is a number */
assert(!MVTYPE_IS_STRING(a_mvtype));
if (TREE_KEY_SUBSCR_IS_CANONICAL(b_mvtype))
{ /* Both aNode and bNode are numbers */
assert(!MVTYPE_IS_STRING(b_mvtype));
aNodeFlt = (lvTreeNodeNum *)aNode;
bNodeFlt = (lvTreeNodeNum *)bNode;
a_mvtype = a_mvtype & MV_INT;
if (a_mvtype & b_mvtype)
{ /* Both aNode & bNode are integers */
a_m1 = aNodeFlt->key_m0;
b_m1 = bNodeFlt->key_m0;
return (a_m1 - b_m1);
}
if (a_mvtype)
{
if (!aNodeFlt->key_flags.key_bits.key_iconv)
lvAvlTreeNodeFltConv(aNodeFlt);
assert(aNodeFlt->key_flags.key_bits.key_iconv);
} else if (b_mvtype = (MV_INT & b_mvtype))
{
if (!bNodeFlt->key_flags.key_bits.key_iconv)
lvAvlTreeNodeFltConv(bNodeFlt);
assert(bNodeFlt->key_flags.key_bits.key_iconv);
}
a_sgn = (0 == aNodeFlt->key_flags.key_bits.key_sgn) ? 1 : -1; /* 1 if positive, -1 if negative */
b_sgn = (0 == bNodeFlt->key_flags.key_bits.key_sgn) ? 1 : -1;
/* Check sign. If different we are done right there */
if (a_sgn != b_sgn)
return a_sgn;
/* Signs equal; compare exponents for magnitude and adjust sense depending on sign. */
exp_diff = aNodeFlt->key_flags.key_bits.key_e - bNodeFlt->key_flags.key_bits.key_e;
if (exp_diff)
return (exp_diff * a_sgn);
/* Signs and exponents equal; compare magnitudes. */
/* First, compare high-order 9 digits of magnitude. */
a_m1 = aNodeFlt->key_m1;
m1_diff = a_m1 - bNodeFlt->key_m1;
if (m1_diff)
return (m1_diff * a_sgn);
/* High-order 9 digits equal; if not zero, compare low-order 9 digits. */
if (0 == a_m1) /* zero special case */
return 0;
/* If key_iconv is TRUE, key_m0 is not lower-order 9 digits but instead is MV_INT representation */
a_m0 = (a_mvtype && aNodeFlt->key_flags.key_bits.key_iconv) ? 0 : aNodeFlt->key_m0;
b_m0 = (b_mvtype && bNodeFlt->key_flags.key_bits.key_iconv) ? 0 : bNodeFlt->key_m0;
m0_diff = a_m0 - b_m0;
if (m0_diff)
return (m0_diff * a_sgn);
/* Signs, exponents, high-order magnitudes, and low-order magnitudes equal. */
return 0;
}
/* aNode is a number, but bNode is a string */
return(-1);
}
/* aNode is a string */
assert(MVTYPE_IS_STRING(a_mvtype));
if (TREE_KEY_SUBSCR_IS_CANONICAL(b_mvtype))
{
assert(!MVTYPE_IS_STRING(b_mvtype));
return(1); /* aNode is a string, but bNode is a number */
}
/* aNode and bNode are both strings */
assert(MVTYPE_IS_STRING(b_mvtype));
MEMVCMP(aNode->key_addr, aNode->key_len, bNode->key_addr, bNode->key_len, retVal);
return retVal;
}
#endif
/* Return first in-order traversal node (also smallest collating key) in avl tree. Returns NULL if NO key in tree */
lvTreeNode *lvAvlTreeFirst(lvTree *lvt)
{
lvTreeNode *avl_first, *next;
next = lvt->avl_root;
if (NULL == next)
return NULL;
do
{
avl_first = next;
next = next->avl_left;
} while (NULL != next);
return avl_first;
}
/* Return last (highest collating) key in avl tree. Returns NULL if NO key in tree */
lvTreeNode *lvAvlTreeLast(lvTree *lvt)
{
lvTreeNode *avl_last, *next;
next = lvt->avl_root;
if (NULL == next)
return NULL;
do
{
avl_last = next;
next = next->avl_right;
} while (NULL != next);
return avl_last;
}
/* Returns the in-order predecessor of the input "node".
* Assumes input is in the avl tree and operates within the avl tree only.
*/
lvTreeNode *lvAvlTreePrev(lvTreeNode *node)
{
lvTreeNode *prev, *tmp, *parent;
assert(NULL != node);
prev = node->avl_left;
if (NULL != prev)
{ /* in-order predecessor is BELOW "node" */
tmp = prev->avl_right;
while (NULL != tmp)
{
prev = tmp;
tmp = prev->avl_right;
}
} else
{ /* in-order predecessor is an ancestor of "node" or could be "" (because "node" is the BIGGEST key in tree) */
parent = node->avl_parent;
tmp = node;
while (NULL != parent)
{
if (parent->avl_right == tmp)
{
prev = parent;
break;
}
assert(parent->avl_left == tmp);
tmp = parent;
parent = tmp->avl_parent;
}
}
return prev;
}
/* Return "node" in AVL tree IMMEDIATELY BEFORE input "key" */
lvTreeNode *lvAvlTreeKeyPrev(lvTree *lvt, treeKeySubscr *key)
{
lvTreeNode *node, *tmp, *prev, *parent;
node = lvAvlTreeLookup(lvt, key, &parent);
if (NULL != node) /* most common case */
{
prev = lvAvlTreePrev(node);
assert((NULL == prev) || (0 < lvAvlTreeKeySubscrCmp(key, prev)));
} else
{
assert(NULL != parent); /* lvAvlTreeLookup should have initialized this */
if (TREE_DESCEND_LEFT == parent->descent_dir)
{
assert(NULL == parent->avl_left);
assert(0 > lvAvlTreeKeySubscrCmp(key, parent));
prev = lvAvlTreePrev(parent);
assert((NULL == prev) || (0 < lvAvlTreeKeySubscrCmp(key, prev)));
} else
{
assert(NULL == parent->avl_right);
assert(0 < lvAvlTreeKeySubscrCmp(key, parent));
DEBUG_ONLY(tmp = lvAvlTreeNext(parent);)
assert((NULL == tmp) || (0 > lvAvlTreeKeySubscrCmp(key, tmp)));
prev = parent;
}
}
return prev;
}
/* Returns the in-order successor of the input "node".
* Assumes input is in the avl tree and operates within the avl tree.
*/
lvTreeNode *lvAvlTreeNext(lvTreeNode *node)
{
lvTreeNode *next, *tmp, *parent;
DEBUG_ONLY(lvTree *lvt;)
assert(NULL != node);
next = node->avl_right;
if (NULL != next)
{ /* in-order successor is BELOW "node" */
tmp = next->avl_left;
while (NULL != tmp)
{
next = tmp;
tmp = next->avl_left;
}
} else
{ /* in-order successor is an ancestor of "node" or could be "" (because "node" is the BIGGEST key in tree) */
parent = node->avl_parent;
tmp = node;
while (NULL != parent)
{
if (parent->avl_left == tmp)
{
next = parent;
break;
}
assert(parent->avl_right == tmp);
tmp = parent;
parent = tmp->avl_parent;
}
}
assert((NULL == next) || (node == lvAvlTreePrev(next)));
return next;
}
/* Return "node" in AVL tree IMMEDIATELY AFTER input "key" */
lvTreeNode *lvAvlTreeKeyNext(lvTree *lvt, treeKeySubscr *key)
{
lvTreeNode *node, *tmp, *next, *parent;
node = lvAvlTreeLookup(lvt, key, &parent);
if (NULL != node) /* most common case */
{
next = lvAvlTreeNext(node);
assert((NULL == next) || (0 > lvAvlTreeKeySubscrCmp(key, next)));
} else
{
assert(NULL != parent); /* lvAvlTreeLookup should have initialized this */
if (TREE_DESCEND_RIGHT == parent->descent_dir)
{
assert(NULL == parent->avl_right);
assert(0 < lvAvlTreeKeySubscrCmp(key, parent));
next = lvAvlTreeNext(parent);
assert((NULL == next) || (0 > lvAvlTreeKeySubscrCmp(key, next)));
} else
{
assert(NULL == parent->avl_left);
assert(0 > lvAvlTreeKeySubscrCmp(key, parent));
DEBUG_ONLY(tmp = lvAvlTreePrev(parent);)
assert((NULL == tmp) || (0 < lvAvlTreeKeySubscrCmp(key, tmp)));
next = parent;
}
}
return next;
}
/* Return first post-order traversal node in avl tree. Returns NULL if NO key in tree */
lvTreeNode *lvAvlTreeFirstPostOrder(lvTree *lvt)
{
lvTreeNode *first, *tmp;
first = lvt->avl_root;
if (NULL == first)
return NULL;
/* Look for first post-order traversal node under left subtree if any. If not look under right sub-tree.
* If neither is present, then this node is it.
*/
do
{
if ((NULL != (tmp = first->avl_left)) || (NULL != (tmp = first->avl_right)))
first = tmp; /* need to go further down the tree to find post-order successor */
else
break; /* found leaf-level post-order successor */
} while (TRUE);
return first;
}
/* Returns the post-order successor of the input "node". Assumes input is in the avl tree and operates within the avl tree. */
lvTreeNode *lvAvlTreeNextPostOrder(lvTreeNode *node)
{
lvTreeNode *next, *tmp, *parent;
assert(NULL != node);
parent = node->avl_parent;
if (NULL == parent) /* Reached root node of the AVL tree in the post order traversal */
return NULL; /* Done with post-order traversal */
if (node == parent->avl_right) /* done with "node" and its subtree so post-order successor is "parent" */
return parent;
assert(node == parent->avl_left);
/* Post-order successor will be in the right subtree of "parent" */
next = parent->avl_right;
if (NULL == next)
return parent; /* No right subtree so "parent" it is */
/* Find post-order successor under the right subtree. Use logic similar to "lvAvlTreeFirstPostOrder" */
do
{
if ((NULL != (tmp = next->avl_left)) || (NULL != (tmp = next->avl_right)))
next = tmp; /* need to go further down the tree to find post-order successor */
else
break; /* found leaf-level post-order successor */
} while (TRUE);
return next;
}
/* Returns the collated successor of the input "key" taking into account the currently effective null collation scheme */
lvTreeNode *lvAvlTreeKeyCollatedNext(lvTree *lvt, treeKeySubscr *key)
{
lvTreeNode *node;
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
if (TREF(local_collseq_stdnull))
{
if (MV_IS_STRING(key) && (0 == key->str.len))
{ /* want the subscript AFTER the null subscript. That is the FIRST node in the tree
* unless the first one happens to also be the null subscript. In that case, we need
* to hop over that and get the next node in the tree.
*/
node = lvAvlTreeFirst(lvt);
} else
{ /* want the subscript AFTER a numeric or string subscript. It could end up resulting
* in the null subscript in case "key" is the highest numeric subscript in the tree.
* In that case, hop over the null subscript as that comes first in the collation order
* even though it comes in between numbers and strings in the tree node storage order.
*/
node = lvAvlTreeKeyNext(lvt, key);
}
/* If "node" holds the NULL subscript, then hop over to the next one. */
if ((NULL != node) && MVTYPE_IS_STRING(node->key_mvtype) && (0 == node->key_len))
node = lvAvlTreeNext(node); /* Need to hop over the null subscript */
} else
node = lvAvlTreeKeyNext(lvt, key);
return node;
}
/* Returns the collated successor of the input "node" taking into account the currently effective null collation scheme */
lvTreeNode *lvAvlTreeNodeCollatedNext(lvTreeNode *node)
{
boolean_t get_next;
lvTree *lvt;
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
if (TREF(local_collseq_stdnull))
{ /* If standard null collation, then null subscript needs special handling.
*
* If current subscript is a null subscript, the next subscript in collation order could
* very well be the first numeric (canonical) subscript in the avl tree (if one exists).
* If not the next subscript would be the first non-null string subscript in the tree.
*
* If current subscript is NOT a null subscript, it is possible we encounter the null
* subscript as the next subscript in collation order. In that case, we need to hop over
* it as that collates before the current numeric subscript.
*/
if ((NULL != node) && MVTYPE_IS_STRING(node->key_mvtype) && (0 == node->key_len))
{
lvt = LV_GET_PARENT_TREE(node);
node = lvAvlTreeFirst(lvt);
assert(NULL != node);
} else
node = lvAvlTreeNext(node);
get_next = ((NULL != node) && MVTYPE_IS_STRING(node->key_mvtype) && (0 == node->key_len));
} else
get_next = TRUE;
if (get_next)
node = lvAvlTreeNext(node);
return node;
}
/* Function to clone an avl tree (used by the LV_TREE_CLONE macro). Uses recursion to descend the tree. */
lvTreeNode *lvAvlTreeCloneSubTree(lvTreeNode *node, lvTree *lvt, lvTreeNode *avl_parent)
{
lvTreeNodeVal *dupVal;
lvTreeNode *cloneNode, *left, *right;
lvTreeNode *leftSubTree, *rightSubTree;
lvTree *lvt_child;
lv_val *base_lv;
assert(NULL != node);
cloneNode = lvtreenode_getslot(LVT_GET_SYMVAL(lvt));
/* The following is optimized to do the initialization of just the needed structure members. For that it assumes a
* particular "lvTreeNode" structure layout. The assumed layout is asserted so any changes to the layout will
* automatically show an issue here and cause the below initialization to be accordingly reworked.
*/
assert(0 == OFFSETOF(lvTreeNode, v));
assert(OFFSETOF(lvTreeNode, v) + SIZEOF(cloneNode->v) == OFFSETOF(lvTreeNode, sbs_child));
assert(OFFSETOF(lvTreeNode, sbs_child) + SIZEOF(cloneNode->sbs_child) == OFFSETOF(lvTreeNode, tree_parent));
assert(OFFSETOF(lvTreeNode, tree_parent) + SIZEOF(cloneNode->tree_parent) == OFFSETOF(lvTreeNode, key_mvtype));
assert(OFFSETOF(lvTreeNode, key_mvtype) + SIZEOF(cloneNode->key_mvtype) == OFFSETOF(lvTreeNode, balance));
assert(OFFSETOF(lvTreeNode, balance) + SIZEOF(cloneNode->balance) == OFFSETOF(lvTreeNode, descent_dir));
assert(OFFSETOF(lvTreeNode, descent_dir) + SIZEOF(cloneNode->descent_dir) == OFFSETOF(lvTreeNode, key_len));
assert(OFFSETOF(lvTreeNode, key_len) + SIZEOF(cloneNode->key_len) == OFFSETOF(lvTreeNode, key_addr));
assert(OFFSETOF(lvTreeNode, key_mvtype) + 8 == OFFSETOF(lvTreeNode, key_addr));
GTM64_ONLY(assert(OFFSETOF(lvTreeNode, key_addr) + SIZEOF(cloneNode->key_addr) == OFFSETOF(lvTreeNode, avl_left));)
NON_GTM64_ONLY(
assert(OFFSETOF(lvTreeNode, key_addr) + SIZEOF(cloneNode->key_addr) == OFFSETOF(lvTreeNode, filler_8byte));
assert(OFFSETOF(lvTreeNode, filler_8byte) + SIZEOF(cloneNode->filler_8byte) == OFFSETOF(lvTreeNode, avl_left));
)
assert(OFFSETOF(lvTreeNode, avl_left) + SIZEOF(cloneNode->avl_left) == OFFSETOF(lvTreeNode, avl_right));
assert(OFFSETOF(lvTreeNode, avl_right) + SIZEOF(cloneNode->avl_right) == OFFSETOF(lvTreeNode, avl_parent));
assert(OFFSETOF(lvTreeNode, avl_parent) + SIZEOF(cloneNode->avl_parent) == SIZEOF(lvTreeNode));
cloneNode->v = node->v;
/* "cloneNode->sbs_child" initialized later */
cloneNode->tree_parent = lvt;
/* cloneNode->key_mvtype/balance/descent_dir/key_len all initialized in one shot */
memcpy(&cloneNode->key_mvtype, &node->key_mvtype, 8); /* Asserts above keep the 8 byte length secure */
cloneNode->key_addr = node->key_addr;
NON_GTM64_ONLY(
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNode, filler_8byte, lvTreeNodeNum, key_m1));
((lvTreeNodeNum *)cloneNode)->key_m1 = ((lvTreeNodeNum *)node)->key_m1;
)
cloneNode->avl_parent = avl_parent;
lvt_child = node->sbs_child;
base_lv = lvt->base_lv;
if (NULL != lvt_child)
{
LV_TREE_CLONE(lvt_child, cloneNode, base_lv); /* initializes "cloneNode->sbs_child" */
} else
cloneNode->sbs_child = NULL;
left = node->avl_left;
leftSubTree = (NULL != left) ? lvAvlTreeCloneSubTree(left, lvt, cloneNode) : NULL;
cloneNode->avl_left = leftSubTree;
right = node->avl_right;
rightSubTree = (NULL != right) ? lvAvlTreeCloneSubTree(right, lvt, cloneNode) : NULL;
cloneNode->avl_right = rightSubTree;
return cloneNode;
}
#ifdef DEBUG
/* Function to check integrity of lv key subscript. Currently tests the MV_CANONICAL bit is in sync with the key type */
STATICFNDEF boolean_t lvAvlTreeLookupKeyCheck(treeKeySubscr *key)
{
mval dummy_mval;
boolean_t is_canonical;
/* Ensure "key->mvtype" comes in with the MV_CANONICAL bit set if applicable */
dummy_mval = *key;
is_canonical = MV_IS_CANONICAL(&dummy_mval);
if (is_canonical)
TREE_KEY_SUBSCR_SET_MV_CANONICAL_BIT(&dummy_mval);
else
TREE_KEY_SUBSCR_RESET_MV_CANONICAL_BIT(&dummy_mval);
assert(TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype) == TREE_KEY_SUBSCR_IS_CANONICAL(dummy_mval.mvtype));
assert(TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype) || MV_IS_STRING(key));
assert(!TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype) || MV_IS_NUMERIC(key));
return TRUE;
}
boolean_t lvTreeIsWellFormed(lvTree *lvt)
{
lvTreeNode *avl_root, *tmpNode, *minNode, *maxNode, *sbs_parent, *avl_node, *node;
treeSrchStatus *lastLookup;
lvTree *tmplvt;
int nm_node_cnt, sbs_depth;
lv_val *base_lv;
if (NULL != lvt)
{
/* Check lvt->ident */
assert(MV_LV_TREE == lvt->ident);
/* Check lvt->sbs_parent */
sbs_parent = LVT_PARENT(lvt);
assert(NULL != sbs_parent);
assert(sbs_parent->sbs_child == lvt);
/* Check lvt->sbs_depth */
sbs_depth = 1;
while (!LV_IS_BASE_VAR(sbs_parent))
{
tmplvt = LV_GET_PARENT_TREE(sbs_parent);
sbs_parent = tmplvt->sbs_parent;
sbs_depth++;
}
assert(sbs_depth == lvt->sbs_depth);
/* Check lvt->base_lv */
assert((lv_val *)sbs_parent == lvt->base_lv);
/* Note: lvt->avl_height is checked in lvAvlTreeNodeIsWellFormed */
/* Check lvt->avl_root */
if (NULL != (avl_root = lvt->avl_root))
{
/* Check lvt->lastLookup clue fields */
lastLookup = &lvt->lastLookup;
if (NULL != (tmpNode = lastLookup->lastNodeLookedUp))
{
minNode = lastLookup->lastNodeMin;
if (NULL != minNode)
assert(0 > lvAvlTreeNodeSubscrCmp(minNode, tmpNode));
maxNode = lastLookup->lastNodeMax;
if (NULL != maxNode)
assert(0 < lvAvlTreeNodeSubscrCmp(maxNode, tmpNode));
}
lvAvlTreeNodeIsWellFormed(lvt, avl_root);
}
}
return TRUE;
}
STATICFNDEF boolean_t lvAvlTreeNodeIsWellFormed(lvTree *lvt, lvTreeNode *node)
{
int leftSubTreeHeight, rightSubTreeHeight;
boolean_t leftWellFormed, rightWellFormed;
lvTreeNode *left, *right;
lvTree *sbs_child;
if (NULL == node)
return TRUE;
assert(node->tree_parent == lvt);
left = node->avl_left;
assert((NULL == left) || (left->avl_parent == node));
right = node->avl_right;
assert((NULL == right) || (right->avl_parent == node));
leftWellFormed = ((NULL == left) || (0 > lvAvlTreeNodeSubscrCmp(left, node)));
assert(leftWellFormed);
rightWellFormed = ((NULL == right) || (0 < lvAvlTreeNodeSubscrCmp(right, node)));
assert(rightWellFormed);
leftSubTreeHeight = lvAvlTreeNodeHeight(left);
rightSubTreeHeight = lvAvlTreeNodeHeight(right);
if (rightSubTreeHeight > leftSubTreeHeight)
assert(node->balance == TREE_RIGHT_HEAVY);
else if (rightSubTreeHeight == leftSubTreeHeight)
assert(node->balance == TREE_BALANCED);
else
assert(node->balance == TREE_LEFT_HEAVY);
if (node == node->tree_parent->avl_root)
assert(node->tree_parent->avl_height == MAX(leftSubTreeHeight, rightSubTreeHeight) + 1);
assert(lvAvlTreeNodeIsWellFormed(lvt, left));
assert(lvAvlTreeNodeIsWellFormed(lvt, right));
sbs_child = node->sbs_child;
if (NULL != sbs_child)
assert(lvTreeIsWellFormed(sbs_child));
return TRUE;
}
STATICFNDEF int lvAvlTreeNodeHeight(lvTreeNode *node)
{
int leftSubTreeHeight, rightSubTreeHeight;
if (NULL != node)
{
leftSubTreeHeight = lvAvlTreeNodeHeight(node->avl_left);
rightSubTreeHeight = lvAvlTreeNodeHeight(node->avl_right);
return (MAX(leftSubTreeHeight, rightSubTreeHeight) + 1);
}
return 0;
}
void assert_tree_member_offsets(void)
{
STATICDEF boolean_t first_tree_create = TRUE;
if (first_tree_create)
{
/* This is the FIRST "lvTree" that this process is creating. Do a few per-process one-time assertions first. */
assert(0 == TREE_LEFT_HEAVY); /* tree_balance_invert array definition depends on this */
assert(1 == TREE_RIGHT_HEAVY); /* tree_balance_invert array definition depends on this */
assert(2 == TREE_BALANCED); /* tree_balance_invert array definition depends on this */
assert(TREE_DESCEND_LEFT == TREE_LEFT_HEAVY); /* they are interchangeably used for performance reasons */
assert(TREE_DESCEND_RIGHT == TREE_RIGHT_HEAVY); /* they are interchangeably used for performance reasons */
/* A lot of the lv functions are passed in an (lv_val *) which could be a (lvTreeNode *) as well.
* For example, in op_kill.c, if "kill a" is done, an "lv_val *" (corresponding to the base local variable "a")
* is passed whereas if "kill a(1,2)" is done, a "lvTreeNode *" (corresponding to the subscripted node "a(1,2)")
* is passed. From the input pointer, we need to determine in op_kill.c if it is a "lv_val *" or "lvTreeNode *".
* Assuming "curr_lv" is the input pointer of type "lv_val *", to find out if it is a pointer to an lv_val or
* lvTreeNode, one checks the ident of the parent. If it is MV_SYM, it means the pointer is to an lv_val (base
* variable) and if not it is a lvTreeNode pointer. The code will look like the below.
*
* if (MV_SYM == curr_lv->ptrs.val_ent.parent.sym->ident)
* { // curr_lv is a base var pointing to an "lv_val" structure
* ...
* } else
* { // curr_lv points to a lvTreeNode structure whose parent.sym field points to a "lvTree" structure
* assert(MV_LV_TREE == curr_lv->ptrs.val_ent.parent.sym->ident);
* ...
* }
*
* Note : The MV_SYM == check above has now been folded into a IS_LV_VAL_PTR macro in lv_val.h
*
* In order for the above check to work, one needs to ensure that that an lv_val.ptrs.val_ent.parent.sym
* is at the same offset and size as a lvTreeNode.tree_parent and that a symval.ident is at the same offset and
* size as a lvTree.ident.
*
* Similarly, in op_fndata.c we could be passed in a base lv_val * or a subscripted lv_val (i.e. lvTreeNode *)
* and want to find out if this lv_val has any children. To do this we would normally need to check
* if the input is an lv_val or a lvTreeNode pointer and access curr_lv->ptrs.val_ent.children or
* curr_lv->sbs_child respectively. To avoid this additional if checks, we ensure that both are at the
* same offset and have the same size.
*
* We therefore ensure that all fields below in the same line should be at same structure offset
* AND have same size as each other. Note: all of this might not be necessary in current code but
* might be useful in the future. Since it is easily possible for us to ensure this, we do so right now.
*
* lvTreeNode.tree_parent == lv_val.ptrs.val_ent.parent.sym
* lvTreeNode.sbs_child == lv_val.ptrs.val_ent.children
* lvTree.ident == symval.ident == lv_val.v.mvtype
* lvTree.sbs_depth == symval.sbs_depth
* lvTreeNode.v == lv_val.v
*/
/* lvTreeNode.tree_parent == lv_val.ptrs.val_ent.parent.sym */
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNode, tree_parent, lv_val, ptrs.val_ent.parent.sym));
/* lvTreeNode.sbs_child == lv_val.ptrs.val_ent.children */
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNode, sbs_child, lv_val, ptrs.val_ent.children));
/* lvTree.ident == symval.ident == lv_val.v.mvtype */
assert(IS_OFFSET_AND_SIZE_MATCH(lvTree, ident, symval, ident));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTree, ident, lv_val, v.mvtype));
/* In order to get OFFSETOF & SIZEOF to work on v.mvtype, the mval field "mvtype" was changed from
* being a 16-bit "unsigned int" type bitfield to a "unsigned short". While this should not affect the
* size of the "mvtype" fields, we fear it might affect the size of the immediately following fields
* "sgn" (1-bit), "e" (7-bit) and "fnpc_index" (8-bit). While all of them together occupy 16-bits, they
* have an "unsigned int" as the type specifier. In order to ensure the compiler does not allocate 4-bytes
* (because of the int specification) to those 3 bitfields (and actually use only 2-bytes of those) and
* create a 2-byte filler space, we assert that the offset of the immediately following non-bitfield (which
* is "m[2]" in Unix & "str" in VMS) in the mval is 4-bytes. If the compiler had allocated 4-bytes, then this
* offset would have been 8-bytes instead and the assert will fail alerting us of the unnecessary mval size bloat.
*/
UNIX_ONLY(assert(4 == OFFSETOF(mval, m[0]));)
VMS_ONLY(assert(4 == OFFSETOF(mval, str));)
/* lvTree.sbs_depth == symval.sbs_depth */
assert(IS_OFFSET_AND_SIZE_MATCH(lvTree, sbs_depth, symval, sbs_depth));
/* lvTreeNode.v == lv_val.v */
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNode, v, lv_val, v));
/* Assert that lvTreeNodeNum and lvTreeNodeStr structures have ALMOST the same layout.
* This makes them interchangeably usable with care on the non-intersecting fields.
*/
assert(SIZEOF(lvTreeNodeNum) == SIZEOF(lvTreeNodeStr));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, v, lvTreeNodeStr, v));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, sbs_child, lvTreeNodeStr, sbs_child));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, tree_parent, lvTreeNodeStr, tree_parent));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, key_mvtype, lvTreeNodeStr, key_mvtype));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, balance, lvTreeNodeStr, balance));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, descent_dir, lvTreeNodeStr, descent_dir));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, avl_left, lvTreeNodeStr, avl_left));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, avl_right, lvTreeNodeStr, avl_right));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeNum, avl_parent, lvTreeNodeStr, avl_parent));
/* Assert that lvTreeNodeStr and lvTreeNode structures have EXACTLY the same layout.
* This makes them interchangeably usable.
*/
assert(SIZEOF(lvTreeNodeStr) == SIZEOF(lvTreeNode));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, v, lvTreeNode, v));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, sbs_child, lvTreeNode, sbs_child));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, tree_parent, lvTreeNode, tree_parent));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, key_mvtype, lvTreeNode, key_mvtype));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, balance, lvTreeNode, balance));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, descent_dir, lvTreeNode, descent_dir));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, key_len, lvTreeNode, key_len));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, key_addr, lvTreeNode, key_addr));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, avl_left, lvTreeNode, avl_left));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, avl_right, lvTreeNode, avl_right));
assert(IS_OFFSET_AND_SIZE_MATCH(lvTreeNodeStr, avl_parent, lvTreeNode, avl_parent));
first_tree_create = FALSE;
}
}
#endif
/* In order to lookup a key in the AVL tree, there are THREE functions. One for each different keytype (integer, number, string).
* lvAvlTreeLookupInt (look up an integer subscript)
* lvAvlTreeLookupNum (look up a non-integer numeric subscript)
* lvAvlTreeLookupStr (look up a string subscript)
* The functions share a lot of code but have slightly different codepaths. Since these functions are frequently invoked,
* we want to keep their cost to a minimum and having separate functions for each keytype lets us minimize the # of if checks
* in them which is why we do it this way even if it means a lot of duplication.
*
* The lookup first attempts to use the clue (if possible) and avoid a full tree traversal.
* If not easily possible, we do the full tree traversal. As part of that, we update the clue (to help with future lookups).
* As this is an AVL tree, the full tree traversal will take O(log(n)) (i.e. logarithmic) time.
*/
lvTreeNode *lvAvlTreeLookupInt(lvTree *lvt, treeKeySubscr *key, lvTreeNode **lookupParent)
{
int cmp;
int4 key_m1;
lvTreeNode *node, *nextNode, *lastNodeMin, *lastNodeMax, *minNode, *maxNode, **nodePtr;
lvTreeNode *parent, *tmpNode;
treeSrchStatus *lastLookup;
assert(lvAvlTreeLookupKeyCheck(key));
assert(TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype));
assert(MVTYPE_IS_INT(key->mvtype));
assert(NULL != lookupParent);
TREE_DEBUG_ONLY(assert(lvTreeIsWellFormed(lvt));)
key_m1 = key->m[1];
/* First see if node can be looked up easily from the lastLookup clue (without a tree traversal) */
lastLookup = &lvt->lastLookup;
if (NULL != (tmpNode = lastLookup->lastNodeLookedUp))
{
assert(NULL != lvt->avl_root); /* there better be an AVL tree if we have a non-zero clue */
LV_AVL_TREE_INTKEY_CMP(key, key_m1, tmpNode, cmp);
if (0 == cmp)
{ /* Input key matches last used clue. Return right away with a match. */
node = tmpNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 < cmp)
{ /* Input key is GREATER than last used clue. Check RIGHT subtree of clue node to see if input key
* could possibly be found there.
*/
if (NULL == tmpNode->avl_right)
{ /* No subtree to the right of the "clue" node.
* If input key is LESSER than the maximum key that can be found under the "clue" node,
* then we know for sure input key can not be found anywhere else in the tree.
* If input key is GREATER than the maximum key then it definitely is not under "clue"
* but could be somewhere else in the tree. We choose to do a fresh traversal from the top.
* If input key is EQUAL to the maximum key then return right away with a match.
*/
maxNode = lastLookup->lastNodeMax;
if (NULL != maxNode)
{
assert(0 < lvAvlTreeNodeSubscrCmp(maxNode, tmpNode));
LV_AVL_TREE_INTKEY_CMP(key, key_m1, maxNode, cmp);
if (0 == cmp)
{ /* input key is EQUAL to the maximum possible key under "clue" node */
node = maxNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 > cmp)
{ /* input key is LESSER than the maximum possible key under "clue" node */
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_RIGHT;
*lookupParent = parent;
return NULL;
}
} else
{ /* Note: maxNode == NULL implies, max key is +INFINITY so treat this case the same way
* as if input key value is LESSER than the maximum possible key under the "clue" node.
*/
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_RIGHT;
*lookupParent = parent;
return NULL;
}
}
} else if (NULL == tmpNode->avl_left)
{ /* Input key is LESSER than last used clue AND no subtree to the left of the "clue" node.
* If input key is GREATER than the minimum key that can be found under the "clue" node,
* then we know for sure input key can not be found anywhere else in the tree.
* If input key is LESSER than the minimum key then it definitely is not under "clue"
* but could be somewhere else in the tree. We choose to do a fresh traversal from the top.
* If input key is EQUAL to the minimum key then return right away with a match.
*/
minNode = lastLookup->lastNodeMin;
if (NULL != minNode)
{
assert(0 > lvAvlTreeNodeSubscrCmp(minNode, tmpNode));
LV_AVL_TREE_INTKEY_CMP(key, key_m1, minNode, cmp);
if (0 == cmp)
{ /* input key is EQUAL to the minimum possible key under "clue" node */
node = minNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 < cmp)
{ /* input key is GREATER than the minimum possible key under "clue" node */
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_LEFT;
*lookupParent = parent;
return NULL;
}
} else
{ /* Note: minNode == NULL implies, min key is -INFINITY so treat this case the same way
* as if input key value is GREATER than the minimum possible key under the "clue" node.
*/
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_LEFT;
*lookupParent = parent;
return NULL;
}
}
}
/* Now that we know "clue" did not help, do a fresh traversal looking for the input key. Maintain clue at the same time */
parent = lvt->avl_root;
if (NULL == parent)
{
*lookupParent = NULL;
return NULL;
}
node = parent;
lastNodeMin = (lvTreeNode *)NULL; /* the minimum possible key under "clue" is initially -INFINITY */
lastNodeMax = (lvTreeNode *)NULL; /* the maximum possible key under "clue" is initially +INFINITY */
if (NULL != node)
{
while (TRUE)
{
LV_AVL_TREE_INTKEY_CMP(key, key_m1, node, cmp);
if (0 == cmp)
{
lvt->lastLookup.lastNodeLookedUp = node;
break;
} else if (cmp < 0)
{
node->descent_dir = TREE_DESCEND_LEFT;
/* if we descend left, we know for sure all-subtree-keys are < node key so update the max key */
nodePtr = &lastNodeMax;
nextNode = node->avl_left;
} else /* (cmp > 0) */
{
node->descent_dir = TREE_DESCEND_RIGHT;
/* if we descend right, we know for sure all-subtree-keys are > node-key so update the min key */
nodePtr = &lastNodeMin;
nextNode = node->avl_right;
}
parent = node;
node = nextNode;
if (NULL == node)
{
lvt->lastLookup.lastNodeLookedUp = parent;
break;
}
*nodePtr = parent; /* the actual max-key or min-key update happens here */
}
} else
lvt->lastLookup.lastNodeLookedUp = NULL;
*lookupParent = parent;
lvt->lastLookup.lastNodeMin = lastNodeMin; /* now that clue has been set, also set max-key and min-key */
lvt->lastLookup.lastNodeMax = lastNodeMax;
return node;
}
/* All comments for "lvAvlTreeLookupInt" function apply here as well */
lvTreeNode *lvAvlTreeLookupNum(lvTree *lvt, treeKeySubscr *key, lvTreeNode **lookupParent)
{
int cmp;
lvTreeNode *node, *nextNode, *lastNodeMin, *lastNodeMax, *minNode, *maxNode, **nodePtr;
lvTreeNode *parent, *tmpNode;
treeSrchStatus *lastLookup;
assert(lvAvlTreeLookupKeyCheck(key));
assert(TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype));
assert(!MVTYPE_IS_INT(key->mvtype));
assert(NULL != lookupParent);
TREE_DEBUG_ONLY(assert(lvTreeIsWellFormed(lvt));)
/* First see if node can be looked up easily from the lastLookup clue (without a tree traversal) */
lastLookup = &lvt->lastLookup;
if (NULL != (tmpNode = lastLookup->lastNodeLookedUp))
{
assert(NULL != lvt->avl_root); /* there better be an AVL tree if we have a non-zero clue */
LV_AVL_TREE_NUMKEY_CMP(key, tmpNode, cmp);
if (0 == cmp)
{ /* Input key matches last used clue. Return right away with a match. */
node = tmpNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 < cmp)
{ /* Input key is GREATER than last used clue. Check RIGHT subtree of clue node to see if input key
* could possibly be found there.
*/
if (NULL == tmpNode->avl_right)
{ /* No subtree to the right of the "clue" node.
* If input key is LESSER than the maximum key that can be found under the "clue" node,
* then we know for sure input key can not be found anywhere else in the tree.
* If input key is GREATER than the maximum key then it definitely is not under "clue"
* but could be somewhere else in the tree. We choose to do a fresh traversal from the top.
* If input key is EQUAL to the maximum key then return right away with a match.
*/
maxNode = lastLookup->lastNodeMax;
if (NULL != maxNode)
{
assert(0 < lvAvlTreeNodeSubscrCmp(maxNode, tmpNode));
LV_AVL_TREE_NUMKEY_CMP(key, maxNode, cmp);
if (0 == cmp)
{ /* input key is EQUAL to the maximum possible key under "clue" node */
node = maxNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 > cmp)
{ /* input key is LESSER than the maximum possible key under "clue" node */
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_RIGHT;
*lookupParent = parent;
return NULL;
}
} else
{ /* Note: maxNode == NULL implies, max key is +INFINITY so treat this case the same way
* as if input key value is LESSER than the maximum possible key under the "clue" node.
*/
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_RIGHT;
*lookupParent = parent;
return NULL;
}
}
} else if (NULL == tmpNode->avl_left)
{ /* Input key is LESSER than last used clue AND no subtree to the left of the "clue" node.
* If input key is GREATER than the minimum key that can be found under the "clue" node,
* then we know for sure input key can not be found anywhere else in the tree.
* If input key is LESSER than the minimum key then it definitely is not under "clue"
* but could be somewhere else in the tree. We choose to do a fresh traversal from the top.
* If input key is EQUAL to the minimum key then return right away with a match.
*/
minNode = lastLookup->lastNodeMin;
if (NULL != minNode)
{
assert(0 > lvAvlTreeNodeSubscrCmp(minNode, tmpNode));
LV_AVL_TREE_NUMKEY_CMP(key, minNode, cmp);
if (0 == cmp)
{ /* input key is EQUAL to the minimum possible key under "clue" node */
node = minNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 < cmp)
{ /* input key is GREATER than the minimum possible key under "clue" node */
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_LEFT;
*lookupParent = parent;
return NULL;
}
} else
{ /* Note: minNode == NULL implies, min key is -INFINITY so treat this case the same way
* as if input key value is GREATER than the minimum possible key under the "clue" node.
*/
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_LEFT;
*lookupParent = parent;
return NULL;
}
}
}
/* Now that we know "clue" did not help, do a fresh traversal looking for the input key. Maintain clue at the same time */
parent = lvt->avl_root;
if (NULL == parent)
{
*lookupParent = NULL;
return NULL;
}
node = parent;
lastNodeMin = (lvTreeNode *)NULL; /* the minimum possible key under "clue" is initially -INFINITY */
lastNodeMax = (lvTreeNode *)NULL; /* the maximum possible key under "clue" is initially +INFINITY */
if (NULL != node)
{
while (TRUE)
{
LV_AVL_TREE_NUMKEY_CMP(key, node, cmp);
if (0 == cmp)
{
lvt->lastLookup.lastNodeLookedUp = node;
break;
} else if (cmp < 0)
{
node->descent_dir = TREE_DESCEND_LEFT;
/* if we descend left, we know for sure all-subtree-keys are < node key so update the max key */
nodePtr = &lastNodeMax;
nextNode = node->avl_left;
} else /* (cmp > 0) */
{
node->descent_dir = TREE_DESCEND_RIGHT;
/* if we descend right, we know for sure all-subtree-keys are > node-key so update the min key */
nodePtr = &lastNodeMin;
nextNode = node->avl_right;
}
parent = node;
node = nextNode;
if (NULL == node)
{
lvt->lastLookup.lastNodeLookedUp = parent;
break;
}
*nodePtr = parent; /* the actual max-key or min-key update happens here */
}
} else
lvt->lastLookup.lastNodeLookedUp = NULL;
*lookupParent = parent;
lvt->lastLookup.lastNodeMin = lastNodeMin; /* now that clue has been set, also set max-key and min-key */
lvt->lastLookup.lastNodeMax = lastNodeMax;
return node;
}
/* All comments for "lvAvlTreeLookupInt" function apply here as well */
lvTreeNode *lvAvlTreeLookupStr(lvTree *lvt, treeKeySubscr *key, lvTreeNode **lookupParent)
{
int cmp, key_len;
char *key_addr;
lvTreeNode *node, *nextNode, *lastNodeMin, *lastNodeMax, *minNode, *maxNode, **nodePtr;
lvTreeNode *parent, *tmpNode;
treeSrchStatus *lastLookup;
assert(lvAvlTreeLookupKeyCheck(key));
assert(!TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype));
assert(MVTYPE_IS_STRING(key->mvtype));
assert(NULL != lookupParent);
TREE_DEBUG_ONLY(assert(lvTreeIsWellFormed(lvt));)
key_addr = key->str.addr;
key_len = key->str.len;
/* First see if node can be looked up easily from the lastLookup clue (without a tree traversal) */
lastLookup = &lvt->lastLookup;
if (NULL != (tmpNode = lastLookup->lastNodeLookedUp))
{
assert(NULL != lvt->avl_root); /* there better be an AVL tree if we have a non-zero clue */
LV_AVL_TREE_STRKEY_CMP(key, key_addr, key_len, tmpNode, cmp);
if (0 == cmp)
{ /* Input key matches last used clue. Return right away with a match. */
node = tmpNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 < cmp)
{ /* Input key is GREATER than last used clue. Check RIGHT subtree of clue node to see if input key
* could possibly be found there.
*/
if (NULL == tmpNode->avl_right)
{ /* No subtree to the right of the "clue" node.
* If input key is LESSER than the maximum key that can be found under the "clue" node,
* then we know for sure input key can not be found anywhere else in the tree.
* If input key is GREATER than the maximum key then it definitely is not under "clue"
* but could be somewhere else in the tree. We choose to do a fresh traversal from the top.
* If input key is EQUAL to the maximum key then return right away with a match.
*/
maxNode = lastLookup->lastNodeMax;
if (NULL != maxNode)
{
assert(0 < lvAvlTreeNodeSubscrCmp(maxNode, tmpNode));
LV_AVL_TREE_STRKEY_CMP(key, key_addr, key_len, maxNode, cmp);
if (0 == cmp)
{ /* input key is EQUAL to the maximum possible key under "clue" node */
node = maxNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 > cmp)
{ /* input key is LESSER than the maximum possible key under "clue" node */
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_RIGHT;
*lookupParent = parent;
return NULL;
}
} else
{ /* Note: maxNode == NULL implies, max key is +INFINITY so treat this case the same way
* as if input key value is LESSER than the maximum possible key under the "clue" node.
*/
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_RIGHT;
*lookupParent = parent;
return NULL;
}
}
} else if (NULL == tmpNode->avl_left)
{ /* Input key is LESSER than last used clue AND no subtree to the left of the "clue" node.
* If input key is GREATER than the minimum key that can be found under the "clue" node,
* then we know for sure input key can not be found anywhere else in the tree.
* If input key is LESSER than the minimum key then it definitely is not under "clue"
* but could be somewhere else in the tree. We choose to do a fresh traversal from the top.
* If input key is EQUAL to the minimum key then return right away with a match.
*/
minNode = lastLookup->lastNodeMin;
if (NULL != minNode)
{
assert(0 > lvAvlTreeNodeSubscrCmp(minNode, tmpNode));
LV_AVL_TREE_STRKEY_CMP(key, key_addr, key_len, minNode, cmp);
if (0 == cmp)
{ /* input key is EQUAL to the minimum possible key under "clue" node */
node = minNode;
/* "parent" or "parent->descent_dir" need not be set since node is non-NULL */
return node;
} else if (0 < cmp)
{ /* input key is GREATER than the minimum possible key under "clue" node */
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_LEFT;
*lookupParent = parent;
return NULL;
}
} else
{ /* Note: minNode == NULL implies, min key is -INFINITY so treat this case the same way
* as if input key value is GREATER than the minimum possible key under the "clue" node.
*/
parent = tmpNode;
parent->descent_dir = TREE_DESCEND_LEFT;
*lookupParent = parent;
return NULL;
}
}
}
/* Now that we know "clue" did not help, do a fresh traversal looking for the input key. Maintain clue at the same time */
parent = lvt->avl_root;
if (NULL == parent)
{
*lookupParent = NULL;
return NULL;
}
node = parent;
lastNodeMin = (lvTreeNode *)NULL; /* the minimum possible key under "clue" is initially -INFINITY */
lastNodeMax = (lvTreeNode *)NULL; /* the maximum possible key under "clue" is initially +INFINITY */
if (NULL != node)
{
while (TRUE)
{
LV_AVL_TREE_STRKEY_CMP(key, key_addr, key_len, node, cmp);
if (0 == cmp)
{
lvt->lastLookup.lastNodeLookedUp = node;
break;
} else if (cmp < 0)
{
node->descent_dir = TREE_DESCEND_LEFT;
/* if we descend left, we know for sure all-subtree-keys are < node key so update the max key */
nodePtr = &lastNodeMax;
nextNode = node->avl_left;
} else /* (cmp > 0) */
{
node->descent_dir = TREE_DESCEND_RIGHT;
/* if we descend right, we know for sure all-subtree-keys are > node-key so update the min key */
nodePtr = &lastNodeMin;
nextNode = node->avl_right;
}
parent = node;
node = nextNode;
if (NULL == node)
{
lvt->lastLookup.lastNodeLookedUp = parent;
break;
}
*nodePtr = parent; /* the actual max-key or min-key update happens here */
}
} else
lvt->lastLookup.lastNodeLookedUp = NULL;
*lookupParent = parent;
lvt->lastLookup.lastNodeMin = lastNodeMin; /* now that clue has been set, also set max-key and min-key */
lvt->lastLookup.lastNodeMax = lastNodeMax;
return node;
}
/* Function to lookup an input key in the AVL tree. This function works for any input key type.
* Returns if a given key is found or not. "lookupParent" will be updated ONLY IF "node" is NOT found in tree.
* Note: It is preferable for performance-sensitive callers to call the lvAvlTreeLookupInt/lvAvlTreeLookupNum/lvAvlTreeLookupStr
* functions directly (assuming the caller already knows the key type) instead of going through here thereby avoiding an if check.
*/
lvTreeNode *lvAvlTreeLookup(lvTree *lvt, treeKeySubscr *key, lvTreeNode **lookupParent)
{
int key_mvtype;
assert(lvAvlTreeLookupKeyCheck(key));
key_mvtype = key->mvtype;
if (TREE_KEY_SUBSCR_IS_CANONICAL(key_mvtype))
{
if (MVTYPE_IS_INT(key_mvtype))
return lvAvlTreeLookupInt(lvt, key, lookupParent);
else
return lvAvlTreeLookupNum(lvt, key, lookupParent);
} else
return lvAvlTreeLookupStr(lvt, key, lookupParent);
}
/* The below two functions (lvAvlTreeSingleRotation & lvAvlTreeDoubleRotation) do height balancing of AVL tree by tree rotation.
* They are used by the "lvAvlTreeNodeInsert" and "lvAvlTreeNodeDelete" functions.
* A node insertion or deletion can cause the AVL tree height balance to be disturbed by taking it to one of 4 states.
* a) Left Left
* b) Right Right
* c) Left Right
* d) Right Left
* Cases (a) and (b) can be taken into a "Balanced" state by just ONE rotation (implemented by lvAvlTreeSingleRotation).
* Cases (c) and (d) need TWO rotations to take them to a "Balanced" state as shown below (implemented by lvAvlTreeDoubleRotation).
*
* In the below illustration (courtesy of http://en.wikipedia.org/wiki/AVL_tree) key points to note are
* -> 3,4,5 are nodes with those key values.
* -> A,B,C,D are arbitrary subtrees (not necessarily nodes).
* -> The double-width link (\\ or //) in each tree is where the rotation happens
* (the child in that link becomes the parent) to take it to the next state.
*
* Left Right case Left Left case Balanced case
* ---------------- ----------------- --------------
*
* ------- ------- -------------
* | 5 | | 5 | | 4 |
* ------- ------- -------------
* / \ // \ / \
* / \ // \ / \
* ------- ------- ------- ------- ------- -------
* | 3 | | D | | 4 | | D | | 3 | | 5 |
* ------- ------- ------- ------- ------- -------
* / \\ ----> / \ ----> / \ / \
* / \\ / \ / \ / \
* ------- ------- ------- ------- ------- ------- ------- -------
* | A | | 4 | | 3 | | C | | A | | B | | C | | D |
* ------- ------- ------- ------- ------- ------- ------- -------
* / \ / \
* / \ / \
* ------- ------- ------- -------
* | B | | C | | A | | B |
* ------- ------- ------- -------
*
* Right Left case Right Right case Balanced case
* ---------------- ----------------- --------------
*
* ------- ------- -------------
* | 3 | | 3 | | 4 |
* ------- ------- -------------
* / \ / \\ / \
* / \ / \\ / \
* ------- ------- ------- ------- ------- -------
* | A | | 5 | | A | | 4 | | 3 | | 5 |
* ------- ------- ------- ------- ------- -------
* // \ ----> / \ ----> / \ / \
* // \ / \ / \ / \
* ------- ------- ------- ------- ------- ------- ------- -------
* | 4 | | D | | B | | 5 | | A | | B | | C | | D |
* ------- ------- ------- ------- ------- ------- ------- -------
* / \ / \
* / \ / \
* ------- ------- ------- -------
* | B | | C | | C | | D |
* ------- ------- ------- -------
*
*/
STATICFNDEF lvTreeNode *lvAvlTreeSingleRotation(lvTreeNode *rebalanceNode, lvTreeNode *anchorNode, int4 balanceFactor)
{
lvTreeNode *newRoot, *node;
TREE_DEBUG1("DOING SINGLE ROTATION\n");
assert((TREE_LEFT_HEAVY == balanceFactor) || (TREE_RIGHT_HEAVY == balanceFactor));
if (TREE_LEFT_HEAVY == balanceFactor)
{ /* Left-Left path rotate. In above illustration, 5 is rebalanceNode, 4 is anchorNode */
assert(rebalanceNode->avl_left == anchorNode);
node = anchorNode->avl_right;
rebalanceNode->avl_left = node;
anchorNode->avl_right = rebalanceNode;
} else
{ /* Right-Right path rotate. In above illustration, 3 is rebalanceNode, 4 is anchorNode */
assert(rebalanceNode->avl_right == anchorNode);
node = anchorNode->avl_left;
rebalanceNode->avl_right = node;
anchorNode->avl_left = rebalanceNode;
}
if (node)
node->avl_parent = rebalanceNode;
rebalanceNode->avl_parent = anchorNode;
if (TREE_IS_NOT_BALANCED(anchorNode->balance))
{
rebalanceNode->balance = TREE_BALANCED;
anchorNode->balance = TREE_BALANCED;
} else
anchorNode->balance = TREE_INVERT_BALANCE_FACTOR(balanceFactor);
newRoot = anchorNode;
return newRoot;
}
/* Comments before "lvAvlTreeSingleRotation" function definition describe what this function does */
STATICFNDEF lvTreeNode *lvAvlTreeDoubleRotation(lvTreeNode *rebalanceNode, lvTreeNode *anchorNode, int4 balanceFactor)
{
lvTreeNode *newRoot, *node, *rebalanceChild, *anchorChild;
int balance;
TREE_DEBUG1("DOING DOUBLE ROTATION\n");
assert((TREE_LEFT_HEAVY == balanceFactor) || (TREE_RIGHT_HEAVY == balanceFactor));
if (TREE_LEFT_HEAVY == balanceFactor)
{ /* Left-Right path rotate. In above illustration, 5 is rebalanceNode, 3 is anchorNode */
assert(rebalanceNode->avl_left == anchorNode);
newRoot = anchorNode->avl_right;
rebalanceChild = newRoot->avl_right;
rebalanceNode->avl_left = rebalanceChild;
anchorChild = newRoot->avl_left;
anchorNode->avl_right = anchorChild;
newRoot->avl_left = anchorNode;
newRoot->avl_right = rebalanceNode;
} else
{ /* Right-Left path rotate. In above illustration, 3 is rebalanceNode, 5 is anchorNode */
assert(rebalanceNode->avl_right == anchorNode);
newRoot = anchorNode->avl_left;
rebalanceChild = newRoot->avl_left;
rebalanceNode->avl_right = rebalanceChild;
anchorChild = newRoot->avl_right;
anchorNode->avl_left = anchorChild;
newRoot->avl_left = rebalanceNode;
newRoot->avl_right = anchorNode;
}
if (NULL != rebalanceChild)
rebalanceChild->avl_parent = rebalanceNode;
if (NULL != anchorChild)
anchorChild->avl_parent = anchorNode;
anchorNode->avl_parent = newRoot;
rebalanceNode->avl_parent = newRoot;
balance = newRoot->balance;
if (balance == balanceFactor)
{
rebalanceNode->balance = TREE_INVERT_BALANCE_FACTOR(balanceFactor);
anchorNode->balance = TREE_BALANCED;
} else if (TREE_IS_BALANCED(balance))
{
rebalanceNode->balance = TREE_BALANCED;
anchorNode->balance = TREE_BALANCED;
} else
{ /* balance & balanceFactor are opposites */
rebalanceNode->balance = TREE_BALANCED;
anchorNode->balance = balanceFactor;
}
newRoot->balance = TREE_BALANCED;
return(newRoot);
}
/* Function to INSERT a node into the AVL tree.
*
* At a high level, insertion proceeds by doing a key lookup first and inserting the key wherever the lookup ends.
* After inserting a node, it is necessary to check each of the node's ancestors for consistency with the rules of AVL.
* For each node checked, if the height difference between the left and right subtrees is atmost 1 then no rotations are necessary.
* If not, then the subtree rooted at this node is unbalanced. It is possible more than one node in the ancestor path is
* unbalanced due to the insertion but at most ONE tree rotation is needed (at the last unbalanced node down the tree path)
* to restore the entire tree to the rules of AVL.
*
* Key points to note for AVL tree insertion are (courtesy of http://neil.brown.name/blog/20041124101820)
*
* When we step down from a node to the longest subtree, that node's tree will not get any larger. If the subtree
* we descend into grows, a rotation will be needed, but this will result in this tree being the same height as it
* was before. The only difference at this level is that it will be balanced whereas it wasn't before. This means
* that when we step down a longer path, we can forget about all the nodes above the one we step down from. They
* cannot be affected as neither of their subtrees will grow. This observation tells us where the rotation has to happen.
*
* We only need to rotate if as part of the lookup/insert, we step down to a longer subtree, and then all
* subsequent nodes are balanced, without longer or shorter subtrees. The actual rotation that happens
* (if needed) will depend on what happens immediately after stepping down to a longer subtree. If the
* next step is in the same direction as the step into the larger subtree, then a SINGLE rotation will be
* needed. If the next step is in the other direction, then a DOUBLE rotation will be needed.
*
* The important data that we need is that part of the path from the last unbalanced node to the insertion
* point. All nodes in this list other than the first will be balanced, including the newly inserted
* node. All of these nodes will either take part in a rotation, or will need to have their balance value
* changed (though the new node won't need it's balance changed, it could take part in a rotation though).
*
* This path may not actually start with an unbalanced node. If every node in the path from the root is
* balanced, then that whole path needs to be recorded, and every node will have it's balance changed.
*
* Time for insert = O(log n) for lookup + O(1) for at most one single or double rotation = O(log n)
*/
lvTreeNode *lvAvlTreeNodeInsert(lvTree *lvt, treeKeySubscr *key, lvTreeNode *parent)
{
lvTreeNode *node, *t_root, *tmp_parent, *anchorNode, *tmpNode, **nodePtr;
lvTreeNode *rebalanceNode, *rebalanceNodeParent;
lvTreeNodeNum *fltNode;
int balanceFactor, curBalance, cmp, key_mvtype;
treeSrchStatus *lastLookup;
DEBUG_ONLY(lvTreeNode *dbg_node);
assert(MV_DEFINED(key));
/* At time of node insertion into tree, ensure that if we have MV_CANONICAL bit set, then MV_STR bit is not set.
* This makes it clear that the node key is a number and does not have the string representation constructed.
*/
assert(!TREE_KEY_SUBSCR_IS_CANONICAL(key->mvtype) || MV_IS_NUMERIC(key) && !MV_IS_STRING(key));
assert(NULL == lvAvlTreeLookup(lvt, key, &tmp_parent));
/* create a node in the avl tree and initialize it */
node = lvtreenode_getslot(LVT_GET_SYMVAL(lvt));
assert(NULL != node);
/* node->v must be initialized by caller */
node->sbs_child = NULL;
node->tree_parent = lvt;
node->avl_left = node->avl_right = NULL;
node->avl_parent = parent;
key_mvtype = key->mvtype;
if (TREE_KEY_SUBSCR_IS_CANONICAL(key_mvtype))
{ /* Initialize lvTreeNodeNum structure */
fltNode = (lvTreeNodeNum *)node;
fltNode->key_mvtype = (key_mvtype & MV_EXT_NUM_MASK);
if (MV_INT & key_mvtype)
{
fltNode->key_m0 = key->m[1];
fltNode->key_flags.key_bits.key_iconv = FALSE;
} else
{
fltNode->key_flags.key_bytes.key_sgne = ((mval_b *)key)->sgne;
fltNode->key_m0 = key->m[0];
fltNode->key_m1 = key->m[1];
}
} else
{ /* Initialize lvTreeNode structure */
node->key_mvtype = MV_STR; /* do not use input mvtype as it might have MV_NM or MV_NUM_APPROX bits set */
node->key_len = key->str.len;
node->key_addr = key->str.addr;
}
node->balance = TREE_BALANCED;
/* node->descent_dir is initialized later when this node is part of a lvAvlTreeLookup operation.
* this field is not used by anyone until then so ok not to initialize it here.
* Update lastLookup clue to reflect the newly inserted node. Note that this clue will continue
* to be valid inspite of any single or double rotations that happen as part of the insert below.
*/
lastLookup = &lvt->lastLookup;
lastLookup->lastNodeLookedUp = node; /* first part of lastLookup clue update */
/* Do height-balancing tree rotations as needed to maintain avl property */
if (NULL != parent)
{
if (TREE_DESCEND_LEFT == parent->descent_dir)
{
parent->avl_left = node;
nodePtr = &lastLookup->lastNodeMax;
} else
{
parent->avl_right = node;
nodePtr = &lastLookup->lastNodeMin;
}
*nodePtr = parent; /* second (and last) part of lastLookup clue update */
t_root = lvt->avl_root;
/* Do balance factor adjustment & rotation as needed */
tmpNode = parent;
while (t_root != tmpNode)
{
balanceFactor = tmpNode->balance;
if (TREE_IS_NOT_BALANCED(balanceFactor))
break;
tmpNode->balance = tmpNode->descent_dir;
tmpNode = tmpNode->avl_parent;
}
rebalanceNode = tmpNode;
if (TREE_DESCEND_LEFT == rebalanceNode->descent_dir)
{
anchorNode = rebalanceNode->avl_left;
balanceFactor = TREE_LEFT_HEAVY;
} else
{
anchorNode = rebalanceNode->avl_right;
balanceFactor = TREE_RIGHT_HEAVY;
}
curBalance = rebalanceNode->balance;
if (TREE_IS_BALANCED(curBalance)) /* tree has grown taller */
{
rebalanceNode->balance = balanceFactor;
TREE_DEBUG3("Tree height increased from %d to %d\n", lvt->avl_height, (lvt->avl_height + 1));
lvt->avl_height++;
assert(1 < lvt->avl_height);
} else if (curBalance == TREE_INVERT_BALANCE_FACTOR(balanceFactor))
{ /* the tree has gotten more balanced */
rebalanceNode->balance = TREE_BALANCED;
} else
{ /* The tree has gotten out of balance so need a rotation */
rebalanceNodeParent = rebalanceNode->avl_parent;
assert(anchorNode->balance == anchorNode->descent_dir);
assert(balanceFactor == rebalanceNode->descent_dir);
if (anchorNode->balance == balanceFactor)
tmpNode = lvAvlTreeSingleRotation(rebalanceNode, anchorNode, balanceFactor);
else
tmpNode = lvAvlTreeDoubleRotation(rebalanceNode, anchorNode, balanceFactor);
tmpNode->avl_parent = rebalanceNodeParent;
if (NULL != rebalanceNodeParent)
{ /* root of tree has NOT changed */
assert(rebalanceNodeParent->descent_dir
== ((rebalanceNodeParent->avl_left == rebalanceNode)
? TREE_DESCEND_LEFT : TREE_DESCEND_RIGHT));
if (TREE_DESCEND_LEFT == rebalanceNodeParent->descent_dir)
rebalanceNodeParent->avl_left = tmpNode;
else
rebalanceNodeParent->avl_right = tmpNode;
} else
lvt->avl_root = tmpNode; /* new root although tree height is still the same */
}
} else
{ /* we just inserted the real root of the tree */
assert(NULL == lvt->avl_root);
lvt->avl_root = node;
assert(NULL == node->avl_right);
assert(NULL == node->avl_left);
assert(TREE_BALANCED == node->balance);
TREE_DEBUG3("Tree height increased from %d to %d\n", lvt->avl_height, (lvt->avl_height + 1));
assert(0 == lvt->avl_height);
lvt->avl_height = 1;
lastLookup->lastNodeMin = NULL; /* ensure lastLookup clue is uptodate */
lastLookup->lastNodeMax = NULL; /* ensure lastLookup clue is uptodate */
}
TREE_DEBUG_ONLY(assert(lvTreeIsWellFormed(lvt));)
return node;
}
/* Function to DELETE a node from the AVL tree.
*
* At a high level, deletion proceeds by doing a key lookup first and deleting the node wherever the lookup ends.
* After deleting a node, it is necessary to check each of the node's ancestors for consistency with the rules of AVL.
* For each node checked, if the height difference between the left and right subtrees is atmost 1 then no rotations are necessary.
* If not, then the subtree rooted at this node is unbalanced. It is possible more than one node in the ancestor path is
* unbalanced due to the deletion. Unlike insertion, MANY (as many as the height of the tree) tree rotations are needed
* to restore the entire tree to the rules of AVL.
*
* Key points to note for AVL tree deletion are (courtesy of http://neil.brown.name/blog/20041124141849)
*
* It is easy to remove a node when it only has one child, as that child can replace the deleted node as the child of
* the grandparent. If the target node has two children, the easiest approach is to swap the node with a node that does
* have at most one child. This can work providing we can find such a node that is adjacent to the target node in the sort-order.
* A few moments consideration will confirm that if a node has two children, then there must be a node both immediately above
* and below it in the sort order, and that both of these must be further down the tree than the target node, and that neither
* of these can have two children (as if they did, then one of the children would lie between that node and the target, which
* contradicts the selection of that node). In this implementation we choose the immediately-above node (in-order successor) only.
*
* While insert only needed one rotation, delete may need rotation at every level.
* If the shrinkage of a subtree (i.e. height reduction due to a tree rotation) causes the node's tree to shrink, the change
* must propagate up. If it does not, then all higher nodes in the tree will not be affected.
*
* Time for delete = O(log n) for lookup + at most O(log n) rotations = O(log n)
*/
void lvAvlTreeNodeDelete(lvTree *lvt, lvTreeNode *node)
{
boolean_t treeBalanced;
int4 balanceFactor, curNodeBalance;
lvTreeNode *balanceThisNode, *nextBalanceThisNode, *anchorNode, *newRoot;
lvTreeNode *next, *nextLeft, *nextRight, *nextParent, *left;
lvTreeNode *nodeLeft, *nodeRight, *nodeParent;
lvTreeNode *rebalanceNode, *rebalanceNodeParent;
assert(IS_LVAVLTREENODE(((lv_val *)node))); /* ensure input "node" is of type "lvTreeNode *" or "lvTreeNodeNum *"
* and not "lv_val *" */
assert(lvt == node->tree_parent);
nodeLeft = node->avl_left;
nodeRight = node->avl_right;
nodeParent = node->avl_parent;
if (NULL == nodeRight)
{ /* No right subtree. Move the left subtree (if it exists) over to the current node. */
balanceThisNode = nodeParent;
if (NULL != balanceThisNode)
{
assert(balanceThisNode->descent_dir
== ((balanceThisNode->avl_left == node) ? TREE_DESCEND_LEFT : TREE_DESCEND_RIGHT));
if (TREE_DESCEND_LEFT == balanceThisNode->descent_dir)
balanceThisNode->avl_left = nodeLeft;
else
balanceThisNode->avl_right = nodeLeft;
} else
{ /* No parent and the fact that this is an AVL tree implies only two possibilities
* a) deleting only node of tree.
* b) deleting root of a height=2 tree that has only one child-node on its left and no other nodes.
* In either case, the tree height will reduce by 1 due to the deletion.
* Set tree root here. Tree height will be reduced later in the rebalancing for loop.
*/
lvt->avl_root = nodeLeft;
}
if (NULL != nodeLeft)
nodeLeft->avl_parent = balanceThisNode;
} else
{ /* Replace node with in-order successor, and rearrange */
next = nodeRight;
while (TRUE)
{
left = next->avl_left;
if (NULL != left)
{
next->descent_dir = TREE_DESCEND_LEFT;
next = left;
} else
break;
}
/* at this point, "next" is the in-order successor of "node" */
assert(NULL == next->avl_left);
nextRight = next->avl_right;
nextParent = next->avl_parent;
if (nextParent != node)
{
balanceThisNode = nextParent;
assert(nextParent->descent_dir
== ((nextParent->avl_left == next) ? TREE_DESCEND_LEFT : TREE_DESCEND_RIGHT));
if (TREE_DESCEND_LEFT == nextParent->descent_dir)
nextParent->avl_left = nextRight;
else
nextParent->avl_right = nextRight;
if (NULL != nextRight)
nextRight->avl_parent = nextParent;
next->avl_right = nodeRight;
nodeRight->avl_parent = next;
} else
{
assert(nextParent->avl_right == next);
balanceThisNode = next;
}
assert(NULL != balanceThisNode);
next->avl_left = nextLeft = nodeLeft;
if (NULL != nextLeft)
nextLeft->avl_parent = next;
next->avl_parent = nodeParent;
next->balance = node->balance;
next->descent_dir = TREE_DESCEND_RIGHT;
if (NULL != nodeParent)
{
assert(nodeParent->descent_dir
== ((nodeParent->avl_left == node) ? TREE_DESCEND_LEFT : TREE_DESCEND_RIGHT));
if (TREE_DESCEND_LEFT == nodeParent->descent_dir)
nodeParent->avl_left = next;
else
nodeParent->avl_right = next;
} else
lvt->avl_root = next; /* root of avl tree changing from "node" to "next" */
}
/* At this point "balanceThisNode" points to the first unbalanced node (from the bottom of the tree path)
* which might also need a rotation (single or double). The rotations need to bubble up the tree hence the for loop.
*/
for ( ; ; balanceThisNode = nextBalanceThisNode)
{ /* Balancing act */
if (NULL == balanceThisNode)
{ /* Went past root of tree as part of balance factor adjustments. Tree height has reduced. */
TREE_DEBUG3("Tree height reduced from %d to %d\n", lvt->avl_height, (lvt->avl_height - 1));
assert(lvt->avl_height > 0);
lvt->avl_height--;
break;
}
balanceFactor = balanceThisNode->descent_dir;
curNodeBalance = balanceThisNode->balance;
if (TREE_IS_BALANCED(curNodeBalance))
{ /* Found a balanced node in the tree path. Fix its balance to account for the decrease in subtree height.
* No more tree rotations needed so break out of the for loop.
*/
balanceThisNode->balance = TREE_INVERT_BALANCE_FACTOR(balanceFactor);
break;
}
nextBalanceThisNode = balanceThisNode->avl_parent;
assert((NULL == nextBalanceThisNode)
|| nextBalanceThisNode->descent_dir
== ((nextBalanceThisNode->avl_left == balanceThisNode) ? TREE_LEFT_HEAVY : TREE_RIGHT_HEAVY));
if (curNodeBalance == balanceFactor)
{ /* The longer subtree is the one which had its height reduce so this node now becomes balanced.
* So no rotation needed for this node, but the height of this node has now reduced so we still
* need to trace back up the tree to see if this causes any more height imbalances.
*/
balanceThisNode->balance = TREE_BALANCED;
continue;
}
/* balanceThisNode->balance == inverse of balanceFactor.
*
* The subtree at balanceThisNode is already heavy on one side and a node delete has caused
* the other side to reduce one more level increasing the height difference between the two
* subtrees to be 2 and therefore requires a rebalance (using tree rotation).
*/
rebalanceNode = balanceThisNode;
if (TREE_LEFT_HEAVY == balanceFactor)
{
balanceFactor = TREE_RIGHT_HEAVY;
anchorNode = rebalanceNode->avl_right;
} else
{
balanceFactor = TREE_LEFT_HEAVY;
anchorNode = rebalanceNode->avl_left;
}
treeBalanced = TREE_IS_BALANCED(anchorNode->balance);
if (treeBalanced || (anchorNode->balance == balanceFactor))
{
newRoot = lvAvlTreeSingleRotation(rebalanceNode, anchorNode, balanceFactor);
assert((treeBalanced && TREE_IS_NOT_BALANCED(rebalanceNode->balance)
&& TREE_IS_NOT_BALANCED(anchorNode->balance))
|| (TREE_IS_BALANCED(rebalanceNode->balance) && TREE_IS_BALANCED(anchorNode->balance)));
} else
newRoot = lvAvlTreeDoubleRotation(rebalanceNode, anchorNode, balanceFactor);
rebalanceNodeParent = nextBalanceThisNode;
newRoot->avl_parent = rebalanceNodeParent;
if (NULL != rebalanceNodeParent)
{ /* Point parent to new root of the rotated subtree */
assert(rebalanceNodeParent->descent_dir
== ((rebalanceNodeParent->avl_left == rebalanceNode) ? TREE_DESCEND_LEFT : TREE_DESCEND_RIGHT));
if (TREE_DESCEND_LEFT == rebalanceNodeParent->descent_dir)
rebalanceNodeParent->avl_left = newRoot;
else
rebalanceNodeParent->avl_right = newRoot;
} else
lvt->avl_root = newRoot;
if (treeBalanced)
{ /* If tree is balanced at "anchorNode" before the rotation, the post-rotated tree height does NOT change.
* This means no more need to propagate the rebalancing up the tree. Break out of the loop now.
*/
break;
}
}
lvt->lastLookup.lastNodeLookedUp = NULL; /* reset lastLookup clue since all bets are off after the delete */
}
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