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The deletion assertion failure reported in RT #112 has been fixed; a pointer

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should have been set to NULL when the top of a level was being rotated but
instead it was set to the node which pointed down to the level of the deleted
node.

rotate_left and rotate_right no longer take a parent parameter, since they
don't need it with the existence of parent pointers.

dns_rbt_deletefromlevel now takes a pointer to the pointer of the root of
the level as a parameter so that it doesn't have to rediscover the root that
its caller (dns_rbt_deletenode) already discovered.

dns_rbt_deletefromlevel did some (minor) pointless work with the sibling of the
deleted node before the color fixup loop was entered; it does so no more.

forward function declarations changed to ISC style.
This commit is contained in:
David Lawrence 2000-05-19 04:42:08 +00:00
parent ea96c33a39
commit 092b4e5359
1 changed files with 52 additions and 99 deletions
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149
lib/dns/rbt.c
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@ -15,14 +15,14 @@
* SOFTWARE. * SOFTWARE.
*/ */
/* $Id: rbt.c,v 1.79 2000/05/08 19:23:13 tale Exp $ */ /* $Id: rbt.c,v 1.80 2000/05/19 04:42:08 tale Exp $ */
/* Principal Authors: DCL */ /* Principal Authors: DCL */
#include <config.h> #include <config.h>
#include <isc/mem.h> #include <isc/mem.h>
#include <isc/string.h> /* Required for HP/UX (and others?) */ #include <isc/string.h>
#include <isc/util.h> #include <isc/util.h>
#include <dns/rbt.h> #include <dns/rbt.h>
@ -159,29 +159,31 @@ static void dns_rbt_printnodename(dns_rbtnode_t *node);
/* /*
* Forward declarations. * Forward declarations.
*/ */
static isc_result_t create_node(isc_mem_t *mctx, static isc_result_t
dns_name_t *name, dns_rbtnode_t **nodep); create_node(isc_mem_t *mctx, dns_name_t *name, dns_rbtnode_t **nodep);
static isc_result_t
join_nodes(dns_rbt_t *rbt, dns_rbtnode_t *node);
static isc_result_t join_nodes(dns_rbt_t *rbt, dns_rbtnode_t *node); static inline isc_result_t
get_ancestor_mem(dns_rbtnodechain_t *chain);
static inline void
put_ancestor_mem(dns_rbtnodechain_t *chain);
static inline isc_result_t get_ancestor_mem(dns_rbtnodechain_t *chain); static inline void
static inline void put_ancestor_mem(dns_rbtnodechain_t *chain); rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp);
static inline void
rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp);
/* static void
* XXXDCL could ditch parent and root arguments to rotate_*, since dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
* now with parent pointers they could figure out the needed pointers dns_rbtnode_t **rootp, dns_rbtnodechain_t *chain);
* themselves. this would slightly simplify dns_rbt_{addon,deletefrom}level.
*/ static void
static inline void rotate_left(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete,
dns_rbtnode_t **rootp);
static inline void rotate_right(dns_rbtnode_t *node, dns_rbtnode_t *parent,
dns_rbtnode_t **rootp); dns_rbtnode_t **rootp);
static void dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, static void
int order, dns_rbtnode_t **rootp, dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
dns_rbtnodechain_t *chain);
static void dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete);
static void dns_rbt_deletetree(dns_rbt_t *rbt, dns_rbtnode_t *node);
/* /*
* Initialize a red/black tree of trees. * Initialize a red/black tree of trees.
@ -1193,7 +1195,8 @@ dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse)
* have one to start, or because it was recursively removed). * have one to start, or because it was recursively removed).
* So now the node needs to be removed from this level. * So now the node needs to be removed from this level.
*/ */
dns_rbt_deletefromlevel(rbt, node); dns_rbt_deletefromlevel(rbt, node,
parent == NULL ? &rbt->root : &DOWN(parent));
if (rbt->data_deleter != NULL) if (rbt->data_deleter != NULL)
rbt->data_deleter(DATA(node), rbt->deleter_arg); rbt->data_deleter(DATA(node), rbt->deleter_arg);
@ -1375,17 +1378,11 @@ join_nodes(dns_rbt_t *rbt, dns_rbtnode_t *node) {
} }
static inline void static inline void
rotate_left(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp) rotate_left(dns_rbtnode_t *node, dns_rbtnode_t **rootp) {
{
dns_rbtnode_t *child; dns_rbtnode_t *child;
REQUIRE(node != NULL); REQUIRE(node != NULL);
REQUIRE(rootp != NULL); REQUIRE(rootp != NULL);
REQUIRE(IS_ROOT(node) ||
RIGHT(parent) == node || LEFT(parent) == node);
INSIST((! IS_ROOT(node) && PARENT(node) == parent) ||
( IS_ROOT(node) && parent == NULL));
child = RIGHT(node); child = RIGHT(node);
INSIST(child != NULL); INSIST(child != NULL);
@ -1404,27 +1401,21 @@ rotate_left(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp)
IS_ROOT(node) = ISC_FALSE; IS_ROOT(node) = ISC_FALSE;
} else { } else {
if (LEFT(parent) == node) if (LEFT(PARENT(node)) == node)
LEFT(parent) = child; LEFT(PARENT(node)) = child;
else else
RIGHT(parent) = child; RIGHT(PARENT(node)) = child;
} }
PARENT(node) = child; PARENT(node) = child;
} }
static inline void static inline void
rotate_right(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp) rotate_right(dns_rbtnode_t *node, dns_rbtnode_t **rootp) {
{
dns_rbtnode_t *child; dns_rbtnode_t *child;
REQUIRE(node != NULL); REQUIRE(node != NULL);
REQUIRE(rootp != NULL); REQUIRE(rootp != NULL);
REQUIRE(IS_ROOT(node) ||
RIGHT(parent) == node || LEFT(parent) == node);
INSIST((! IS_ROOT(node) && PARENT(node) == parent) ||
( IS_ROOT(node) && parent == NULL));
child = LEFT(node); child = LEFT(node);
INSIST(child != NULL); INSIST(child != NULL);
@ -1443,10 +1434,10 @@ rotate_right(dns_rbtnode_t *node, dns_rbtnode_t *parent, dns_rbtnode_t **rootp)
IS_ROOT(node) = ISC_FALSE; IS_ROOT(node) = ISC_FALSE;
} else { } else {
if (LEFT(parent) == node) if (LEFT(PARENT(node)) == node)
LEFT(parent) = child; LEFT(PARENT(node)) = child;
else else
RIGHT(parent) = child; RIGHT(PARENT(node)) = child;
} }
PARENT(node) = child; PARENT(node) = child;
@ -1521,8 +1512,7 @@ dns_rbt_addonlevel(dns_rbtnode_t *node,
depth -= 2; depth -= 2;
} else { } else {
if (node == RIGHT(parent)) { if (node == RIGHT(parent)) {
rotate_left(parent, grandparent, rotate_left(parent, &root);
&root);
tmp = node; tmp = node;
node = parent; node = parent;
parent = tmp; parent = tmp;
@ -1531,9 +1521,7 @@ dns_rbt_addonlevel(dns_rbtnode_t *node,
MAKE_BLACK(parent); MAKE_BLACK(parent);
MAKE_RED(grandparent); MAKE_RED(grandparent);
INSIST(depth > 1); INSIST(depth > 1);
rotate_right(grandparent, rotate_right(grandparent, &root);
chain->ancestors[depth - 2],
&root);
} }
} else { } else {
child = LEFT(grandparent); child = LEFT(grandparent);
@ -1545,8 +1533,7 @@ dns_rbt_addonlevel(dns_rbtnode_t *node,
depth -= 2; depth -= 2;
} else { } else {
if (node == LEFT(parent)) { if (node == LEFT(parent)) {
rotate_right(parent, grandparent, rotate_right(parent, &root);
&root);
tmp = node; tmp = node;
node = parent; node = parent;
parent = tmp; parent = tmp;
@ -1555,9 +1542,7 @@ dns_rbt_addonlevel(dns_rbtnode_t *node,
MAKE_BLACK(parent); MAKE_BLACK(parent);
MAKE_RED(grandparent); MAKE_RED(grandparent);
INSIST(depth > 1); INSIST(depth > 1);
rotate_left(grandparent, rotate_left(grandparent, &root);
chain->ancestors[depth - 2],
&root);
} }
} }
} }
@ -1574,21 +1559,15 @@ dns_rbt_addonlevel(dns_rbtnode_t *node,
* true red/black tree on a single level. * true red/black tree on a single level.
*/ */
static void static void
dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete) { dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete,
dns_rbtnode_t *child, *sibling, *parent, *grandparent; dns_rbtnode_t **rootp)
dns_rbtnode_t *successor, *root, **rootp; {
dns_rbtnode_t *child, *sibling, *parent;
dns_rbtnode_t *successor;
REQUIRE(VALID_RBT(rbt)); REQUIRE(VALID_RBT(rbt));
REQUIRE(delete != NULL); REQUIRE(delete != NULL);
for (root = delete; ! IS_ROOT(root); root = PARENT(root))
; /* Nothing. */
if (PARENT(root) != NULL)
rootp = &DOWN(PARENT(root));
else
rootp = &rbt->root;
/* /*
* Verify that the parent history is (apparently) correct. * Verify that the parent history is (apparently) correct.
*/ */
@ -1708,17 +1687,13 @@ dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete) {
* Remove the node by removing the links from its parent. * Remove the node by removing the links from its parent.
*/ */
if (! IS_ROOT(delete)) { if (! IS_ROOT(delete)) {
if (LEFT(PARENT(delete)) == delete) { if (LEFT(PARENT(delete)) == delete)
LEFT(PARENT(delete)) = child; LEFT(PARENT(delete)) = child;
sibling = RIGHT(PARENT(delete)); else
} else {
RIGHT(PARENT(delete)) = child; RIGHT(PARENT(delete)) = child;
sibling = LEFT(PARENT(delete));
}
if (child != NULL) if (child != NULL)
PARENT(child) = PARENT(delete); PARENT(child) = PARENT(delete);
if (sibling != NULL)
PARENT(sibling) = PARENT(delete);
} else { } else {
/* /*
@ -1739,23 +1714,13 @@ dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete) {
while (child != *rootp && IS_BLACK(child)) { while (child != *rootp && IS_BLACK(child)) {
INSIST(child == NULL || ! IS_ROOT(child)); INSIST(child == NULL || ! IS_ROOT(child));
grandparent = parent->parent;
if (LEFT(parent) == child) { if (LEFT(parent) == child) {
sibling = RIGHT(parent); sibling = RIGHT(parent);
if (IS_RED(sibling)) { if (IS_RED(sibling)) {
MAKE_BLACK(sibling); MAKE_BLACK(sibling);
MAKE_RED(parent); MAKE_RED(parent);
rotate_left(parent, grandparent, rotate_left(parent, rootp);
rootp);
/*
* Parent was reparented by the
* rotation, so the new grandparent
* needs to be noted. Grandpa is dead,
* long live grandpa.
*/
grandparent = sibling;
sibling = RIGHT(parent); sibling = RIGHT(parent);
} }
@ -1769,16 +1734,14 @@ dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete) {
if (IS_BLACK(RIGHT(sibling))) { if (IS_BLACK(RIGHT(sibling))) {
MAKE_BLACK(LEFT(sibling)); MAKE_BLACK(LEFT(sibling));
MAKE_RED(sibling); MAKE_RED(sibling);
rotate_right(sibling, parent, rotate_right(sibling, rootp);
rootp);
sibling = RIGHT(parent); sibling = RIGHT(parent);
} }
COLOR(sibling) = COLOR(parent); COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent); MAKE_BLACK(parent);
MAKE_BLACK(RIGHT(sibling)); MAKE_BLACK(RIGHT(sibling));
rotate_left(parent, grandparent, rotate_left(parent, rootp);
rootp);
child = *rootp; child = *rootp;
} }
@ -1793,15 +1756,7 @@ dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete) {
if (IS_RED(sibling)) { if (IS_RED(sibling)) {
MAKE_BLACK(sibling); MAKE_BLACK(sibling);
MAKE_RED(parent); MAKE_RED(parent);
rotate_right(parent, grandparent, rotate_right(parent, rootp);
rootp);
/*
* Parent was reparented by the
* rotation, so the new grandparent
* needs to be noted. Grandma is dead,
* long live grandma.
*/
grandparent = sibling;
sibling = LEFT(parent); sibling = LEFT(parent);
} }
@ -1814,21 +1769,19 @@ dns_rbt_deletefromlevel(dns_rbt_t *rbt, dns_rbtnode_t *delete) {
if (IS_BLACK(LEFT(sibling))) { if (IS_BLACK(LEFT(sibling))) {
MAKE_BLACK(RIGHT(sibling)); MAKE_BLACK(RIGHT(sibling));
MAKE_RED(sibling); MAKE_RED(sibling);
rotate_left(sibling, parent, rotate_left(sibling, rootp);
rootp);
sibling = LEFT(parent); sibling = LEFT(parent);
} }
COLOR(sibling) = COLOR(parent); COLOR(sibling) = COLOR(parent);
MAKE_BLACK(parent); MAKE_BLACK(parent);
MAKE_BLACK(LEFT(sibling)); MAKE_BLACK(LEFT(sibling));
rotate_right(parent, grandparent, rotate_right(parent, rootp);
rootp);
child = *rootp; child = *rootp;
} }
} }
parent = child->parent; parent = PARENT(child);
} }
if (IS_RED(child)) if (IS_RED(child))