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Kurt Zeilenga 2003-11-26 22:32:36 +00:00
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778
libraries/liblutil/avl.c Normal file
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/* avl.c - routines to implement an avl tree */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 1998-2003 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
/* Portions Copyright (c) 1993 Regents of the University of Michigan.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and that due credit is given
* to the University of Michigan at Ann Arbor. The name of the University
* may not be used to endorse or promote products derived from this
* software without specific prior written permission. This software
* is provided ``as is'' without express or implied warranty.
*/
/* ACKNOWLEDGEMENTS:
* This work was originally developed by the University of Michigan
* (as part of U-MICH LDAP). Additional significant contributors
* include:
* Hallvard B. Furuseth
* Kurt D. Zeilenga
*/
#include "portable.h"
#include <stdio.h>
#include <ac/stdlib.h>
#ifdef CSRIMALLOC
#define ber_memalloc malloc
#define ber_memrealloc realloc
#define ber_memfree free
#else
#include "lber.h"
#endif
#define AVL_INTERNAL
#include "avl.h"
#define ROTATERIGHT(x) { \
Avlnode *tmp;\
if ( *(x) == NULL || (*(x))->avl_left == NULL ) {\
(void) fputs("RR error\n", stderr); exit( EXIT_FAILURE ); \
}\
tmp = (*(x))->avl_left;\
(*(x))->avl_left = tmp->avl_right;\
tmp->avl_right = *(x);\
*(x) = tmp;\
}
#define ROTATELEFT(x) { \
Avlnode *tmp;\
if ( *(x) == NULL || (*(x))->avl_right == NULL ) {\
(void) fputs("RL error\n", stderr); exit( EXIT_FAILURE ); \
}\
tmp = (*(x))->avl_right;\
(*(x))->avl_right = tmp->avl_left;\
tmp->avl_left = *(x);\
*(x) = tmp;\
}
/*
* ravl_insert - called from avl_insert() to do a recursive insert into
* and balance of an avl tree.
*/
static int
ravl_insert(
Avlnode **iroot,
void* data,
int *taller,
AVL_CMP fcmp, /* comparison function */
AVL_DUP fdup, /* function to call for duplicates */
int depth
)
{
int rc, cmp, tallersub;
Avlnode *l, *r;
if ( *iroot == 0 ) {
if ( (*iroot = (Avlnode *) ber_memalloc( sizeof( Avlnode ) ))
== NULL ) {
return( -1 );
}
(*iroot)->avl_left = 0;
(*iroot)->avl_right = 0;
(*iroot)->avl_bf = 0;
(*iroot)->avl_data = data;
*taller = 1;
return( 0 );
}
cmp = (*fcmp)( data, (*iroot)->avl_data );
/* equal - duplicate name */
if ( cmp == 0 ) {
*taller = 0;
return( (*fdup)( (*iroot)->avl_data, data ) );
}
/* go right */
else if ( cmp > 0 ) {
rc = ravl_insert( &((*iroot)->avl_right), data, &tallersub,
fcmp, fdup, depth );
if ( tallersub )
switch ( (*iroot)->avl_bf ) {
case LH : /* left high - balance is restored */
(*iroot)->avl_bf = EH;
*taller = 0;
break;
case EH : /* equal height - now right heavy */
(*iroot)->avl_bf = RH;
*taller = 1;
break;
case RH : /* right heavy to start - right balance */
r = (*iroot)->avl_right;
switch ( r->avl_bf ) {
case LH : /* double rotation left */
l = r->avl_left;
switch ( l->avl_bf ) {
case LH : (*iroot)->avl_bf = EH;
r->avl_bf = RH;
break;
case EH : (*iroot)->avl_bf = EH;
r->avl_bf = EH;
break;
case RH : (*iroot)->avl_bf = LH;
r->avl_bf = EH;
break;
}
l->avl_bf = EH;
ROTATERIGHT( (&r) )
(*iroot)->avl_right = r;
ROTATELEFT( iroot )
*taller = 0;
break;
case EH : /* This should never happen */
break;
case RH : /* single rotation left */
(*iroot)->avl_bf = EH;
r->avl_bf = EH;
ROTATELEFT( iroot )
*taller = 0;
break;
}
break;
}
else
*taller = 0;
}
/* go left */
else {
rc = ravl_insert( &((*iroot)->avl_left), data, &tallersub,
fcmp, fdup, depth );
if ( tallersub )
switch ( (*iroot)->avl_bf ) {
case LH : /* left high to start - left balance */
l = (*iroot)->avl_left;
switch ( l->avl_bf ) {
case LH : /* single rotation right */
(*iroot)->avl_bf = EH;
l->avl_bf = EH;
ROTATERIGHT( iroot )
*taller = 0;
break;
case EH : /* this should never happen */
break;
case RH : /* double rotation right */
r = l->avl_right;
switch ( r->avl_bf ) {
case LH : (*iroot)->avl_bf = RH;
l->avl_bf = EH;
break;
case EH : (*iroot)->avl_bf = EH;
l->avl_bf = EH;
break;
case RH : (*iroot)->avl_bf = EH;
l->avl_bf = LH;
break;
}
r->avl_bf = EH;
ROTATELEFT( (&l) )
(*iroot)->avl_left = l;
ROTATERIGHT( iroot )
*taller = 0;
break;
}
break;
case EH : /* equal height - now left heavy */
(*iroot)->avl_bf = LH;
*taller = 1;
break;
case RH : /* right high - balance is restored */
(*iroot)->avl_bf = EH;
*taller = 0;
break;
}
else
*taller = 0;
}
return( rc );
}
/*
* avl_insert -- insert a node containing data data into the avl tree
* with root root. fcmp is a function to call to compare the data portion
* of two nodes. it should take two arguments and return <, >, or == 0,
* depending on whether its first argument is <, >, or == its second
* argument (like strcmp, e.g.). fdup is a function to call when a duplicate
* node is inserted. it should return 0, or -1 and its return value
* will be the return value from avl_insert in the case of a duplicate node.
* the function will be called with the original node's data as its first
* argument and with the incoming duplicate node's data as its second
* argument. this could be used, for example, to keep a count with each
* node.
*
* NOTE: this routine may malloc memory
*/
int
avl_insert( Avlnode **root, void* data, AVL_CMP fcmp, AVL_DUP fdup )
{
int taller;
return( ravl_insert( root, data, &taller, fcmp, fdup, 0 ) );
}
/*
* right_balance() - called from delete when root's right subtree has
* been shortened because of a deletion.
*/
static int
right_balance( Avlnode **root )
{
int shorter = -1;
Avlnode *r, *l;
switch( (*root)->avl_bf ) {
case RH: /* was right high - equal now */
(*root)->avl_bf = EH;
shorter = 1;
break;
case EH: /* was equal - left high now */
(*root)->avl_bf = LH;
shorter = 0;
break;
case LH: /* was right high - balance */
l = (*root)->avl_left;
switch ( l->avl_bf ) {
case RH : /* double rotation left */
r = l->avl_right;
switch ( r->avl_bf ) {
case RH :
(*root)->avl_bf = EH;
l->avl_bf = LH;
break;
case EH :
(*root)->avl_bf = EH;
l->avl_bf = EH;
break;
case LH :
(*root)->avl_bf = RH;
l->avl_bf = EH;
break;
}
r->avl_bf = EH;
ROTATELEFT( (&l) )
(*root)->avl_left = l;
ROTATERIGHT( root )
shorter = 1;
break;
case EH : /* right rotation */
(*root)->avl_bf = LH;
l->avl_bf = RH;
ROTATERIGHT( root );
shorter = 0;
break;
case LH : /* single rotation right */
(*root)->avl_bf = EH;
l->avl_bf = EH;
ROTATERIGHT( root )
shorter = 1;
break;
}
break;
}
return( shorter );
}
/*
* left_balance() - called from delete when root's left subtree has
* been shortened because of a deletion.
*/
static int
left_balance( Avlnode **root )
{
int shorter = -1;
Avlnode *r, *l;
switch( (*root)->avl_bf ) {
case LH: /* was left high - equal now */
(*root)->avl_bf = EH;
shorter = 1;
break;
case EH: /* was equal - right high now */
(*root)->avl_bf = RH;
shorter = 0;
break;
case RH: /* was right high - balance */
r = (*root)->avl_right;
switch ( r->avl_bf ) {
case LH : /* double rotation left */
l = r->avl_left;
switch ( l->avl_bf ) {
case LH :
(*root)->avl_bf = EH;
r->avl_bf = RH;
break;
case EH :
(*root)->avl_bf = EH;
r->avl_bf = EH;
break;
case RH :
(*root)->avl_bf = LH;
r->avl_bf = EH;
break;
}
l->avl_bf = EH;
ROTATERIGHT( (&r) )
(*root)->avl_right = r;
ROTATELEFT( root )
shorter = 1;
break;
case EH : /* single rotation left */
(*root)->avl_bf = RH;
r->avl_bf = LH;
ROTATELEFT( root );
shorter = 0;
break;
case RH : /* single rotation left */
(*root)->avl_bf = EH;
r->avl_bf = EH;
ROTATELEFT( root )
shorter = 1;
break;
}
break;
}
return( shorter );
}
/*
* ravl_delete() - called from avl_delete to do recursive deletion of a
* node from an avl tree. It finds the node recursively, deletes it,
* and returns shorter if the tree is shorter after the deletion and
* rebalancing.
*/
static void*
ravl_delete( Avlnode **root, void* data, AVL_CMP fcmp, int *shorter )
{
int shortersubtree = 0;
int cmp;
void* savedata;
Avlnode *minnode, *savenode;
if ( *root == NULLAVL )
return( 0 );
cmp = (*fcmp)( data, (*root)->avl_data );
/* found it! */
if ( cmp == 0 ) {
savenode = *root;
savedata = savenode->avl_data;
/* simple cases: no left child */
if ( (*root)->avl_left == 0 ) {
*root = (*root)->avl_right;
*shorter = 1;
ber_memfree( (char *) savenode );
return( savedata );
/* no right child */
} else if ( (*root)->avl_right == 0 ) {
*root = (*root)->avl_left;
*shorter = 1;
ber_memfree( (char *) savenode );
return( savedata );
}
/*
* avl_getmin will return to us the smallest node greater
* than the one we are trying to delete. deleting this node
* from the right subtree is guaranteed to end in one of the
* simple cases above.
*/
minnode = (*root)->avl_right;
while ( minnode->avl_left != NULLAVL )
minnode = minnode->avl_left;
/* swap the data */
(*root)->avl_data = minnode->avl_data;
minnode->avl_data = savedata;
savedata = ravl_delete( &(*root)->avl_right, data, fcmp,
&shortersubtree );
if ( shortersubtree )
*shorter = right_balance( root );
else
*shorter = 0;
/* go left */
} else if ( cmp < 0 ) {
if ( (savedata = ravl_delete( &(*root)->avl_left, data, fcmp,
&shortersubtree )) == 0 ) {
*shorter = 0;
return( 0 );
}
/* left subtree shorter? */
if ( shortersubtree )
*shorter = left_balance( root );
else
*shorter = 0;
/* go right */
} else {
if ( (savedata = ravl_delete( &(*root)->avl_right, data, fcmp,
&shortersubtree )) == 0 ) {
*shorter = 0;
return( 0 );
}
if ( shortersubtree )
*shorter = right_balance( root );
else
*shorter = 0;
}
return( savedata );
}
/*
* avl_delete() - deletes the node containing data (according to fcmp) from
* the avl tree rooted at root.
*/
void*
avl_delete( Avlnode **root, void* data, AVL_CMP fcmp )
{
int shorter;
return( ravl_delete( root, data, fcmp, &shorter ) );
}
static int
avl_inapply( Avlnode *root, AVL_APPLY fn, void* arg, int stopflag )
{
if ( root == 0 )
return( AVL_NOMORE );
if ( root->avl_left != 0 )
if ( avl_inapply( root->avl_left, fn, arg, stopflag )
== stopflag )
return( stopflag );
if ( (*fn)( root->avl_data, arg ) == stopflag )
return( stopflag );
if ( root->avl_right == 0 )
return( AVL_NOMORE );
else
return( avl_inapply( root->avl_right, fn, arg, stopflag ) );
}
static int
avl_postapply( Avlnode *root, AVL_APPLY fn, void* arg, int stopflag )
{
if ( root == 0 )
return( AVL_NOMORE );
if ( root->avl_left != 0 )
if ( avl_postapply( root->avl_left, fn, arg, stopflag )
== stopflag )
return( stopflag );
if ( root->avl_right != 0 )
if ( avl_postapply( root->avl_right, fn, arg, stopflag )
== stopflag )
return( stopflag );
return( (*fn)( root->avl_data, arg ) );
}
static int
avl_preapply( Avlnode *root, AVL_APPLY fn, void* arg, int stopflag )
{
if ( root == 0 )
return( AVL_NOMORE );
if ( (*fn)( root->avl_data, arg ) == stopflag )
return( stopflag );
if ( root->avl_left != 0 )
if ( avl_preapply( root->avl_left, fn, arg, stopflag )
== stopflag )
return( stopflag );
if ( root->avl_right == 0 )
return( AVL_NOMORE );
else
return( avl_preapply( root->avl_right, fn, arg, stopflag ) );
}
/*
* avl_apply -- avl tree root is traversed, function fn is called with
* arguments arg and the data portion of each node. if fn returns stopflag,
* the traversal is cut short, otherwise it continues. Do not use -6 as
* a stopflag, as this is what is used to indicate the traversal ran out
* of nodes.
*/
int
avl_apply( Avlnode *root, AVL_APPLY fn, void* arg, int stopflag, int type )
{
switch ( type ) {
case AVL_INORDER:
return( avl_inapply( root, fn, arg, stopflag ) );
case AVL_PREORDER:
return( avl_preapply( root, fn, arg, stopflag ) );
case AVL_POSTORDER:
return( avl_postapply( root, fn, arg, stopflag ) );
default:
fprintf( stderr, "Invalid traversal type %d\n", type );
return( -1 );
}
/* NOTREACHED */
}
/*
* avl_prefixapply - traverse avl tree root, applying function fprefix
* to any nodes that match. fcmp is called with data as its first arg
* and the current node's data as its second arg. it should return
* 0 if they match, < 0 if data is less, and > 0 if data is greater.
* the idea is to efficiently find all nodes that are prefixes of
* some key... Like avl_apply, this routine also takes a stopflag
* and will return prematurely if fmatch returns this value. Otherwise,
* AVL_NOMORE is returned.
*/
int
avl_prefixapply(
Avlnode *root,
void* data,
AVL_CMP fmatch,
void* marg,
AVL_CMP fcmp,
void* carg,
int stopflag
)
{
int cmp;
if ( root == 0 )
return( AVL_NOMORE );
cmp = (*fcmp)( data, root->avl_data /* , carg */);
if ( cmp == 0 ) {
if ( (*fmatch)( root->avl_data, marg ) == stopflag )
return( stopflag );
if ( root->avl_left != 0 )
if ( avl_prefixapply( root->avl_left, data, fmatch,
marg, fcmp, carg, stopflag ) == stopflag )
return( stopflag );
if ( root->avl_right != 0 )
return( avl_prefixapply( root->avl_right, data, fmatch,
marg, fcmp, carg, stopflag ) );
else
return( AVL_NOMORE );
} else if ( cmp < 0 ) {
if ( root->avl_left != 0 )
return( avl_prefixapply( root->avl_left, data, fmatch,
marg, fcmp, carg, stopflag ) );
} else {
if ( root->avl_right != 0 )
return( avl_prefixapply( root->avl_right, data, fmatch,
marg, fcmp, carg, stopflag ) );
}
return( AVL_NOMORE );
}
/*
* avl_free -- traverse avltree root, freeing the memory it is using.
* the dfree() is called to free the data portion of each node. The
* number of items actually freed is returned.
*/
int
avl_free( Avlnode *root, AVL_FREE dfree )
{
int nleft, nright;
if ( root == 0 )
return( 0 );
nleft = nright = 0;
if ( root->avl_left != 0 )
nleft = avl_free( root->avl_left, dfree );
if ( root->avl_right != 0 )
nright = avl_free( root->avl_right, dfree );
if ( dfree )
(*dfree)( root->avl_data );
ber_memfree( root );
return( nleft + nright + 1 );
}
/*
* avl_find -- search avltree root for a node with data data. the function
* cmp is used to compare things. it is called with data as its first arg
* and the current node data as its second. it should return 0 if they match,
* < 0 if arg1 is less than arg2 and > 0 if arg1 is greater than arg2.
*/
void*
avl_find( Avlnode *root, const void* data, AVL_CMP fcmp )
{
int cmp;
while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
if ( cmp < 0 )
root = root->avl_left;
else
root = root->avl_right;
}
return( root ? root->avl_data : 0 );
}
/*
* avl_find_lin -- search avltree root linearly for a node with data data.
* the function cmp is used to compare things. it is called with data as its
* first arg and the current node data as its second. it should return 0 if
* they match, non-zero otherwise.
*/
void*
avl_find_lin( Avlnode *root, const void* data, AVL_CMP fcmp )
{
void* res;
if ( root == 0 )
return( NULL );
if ( (*fcmp)( data, root->avl_data ) == 0 )
return( root->avl_data );
if ( root->avl_left != 0 )
if ( (res = avl_find_lin( root->avl_left, data, fcmp ))
!= NULL )
return( res );
if ( root->avl_right == 0 )
return( NULL );
else
return( avl_find_lin( root->avl_right, data, fcmp ) );
}
/* NON-REENTRANT INTERFACE */
static void* *avl_list;
static int avl_maxlist;
static int avl_nextlist;
#define AVL_GRABSIZE 100
/* ARGSUSED */
static int
avl_buildlist( void* data, void* arg )
{
static int slots;
if ( avl_list == (void* *) 0 ) {
avl_list = (void* *) ber_memalloc(AVL_GRABSIZE * sizeof(void*));
slots = AVL_GRABSIZE;
avl_maxlist = 0;
} else if ( avl_maxlist == slots ) {
slots += AVL_GRABSIZE;
avl_list = (void* *) ber_memrealloc( (char *) avl_list,
(unsigned) slots * sizeof(void*));
}
avl_list[ avl_maxlist++ ] = data;
return( 0 );
}
/*
* avl_getfirst() and avl_getnext() are provided as alternate tree
* traversal methods, to be used when a single function cannot be
* provided to be called with every node in the tree. avl_getfirst()
* traverses the tree and builds a linear list of all the nodes,
* returning the first node. avl_getnext() returns the next thing
* on the list built by avl_getfirst(). This means that avl_getfirst()
* can take a while, and that the tree should not be messed with while
* being traversed in this way, and that multiple traversals (even of
* different trees) cannot be active at once.
*/
void*
avl_getfirst( Avlnode *root )
{
if ( avl_list ) {
ber_memfree( (char *) avl_list);
avl_list = (void* *) 0;
}
avl_maxlist = 0;
avl_nextlist = 0;
if ( root == 0 )
return( 0 );
(void) avl_apply( root, avl_buildlist, (void*) 0, -1, AVL_INORDER );
return( avl_list[ avl_nextlist++ ] );
}
void*
avl_getnext( void )
{
if ( avl_list == 0 )
return( 0 );
if ( avl_nextlist == avl_maxlist ) {
ber_memfree( (void*) avl_list);
avl_list = (void* *) 0;
return( 0 );
}
return( avl_list[ avl_nextlist++ ] );
}
/* end non-reentrant code */
int
avl_dup_error( void* left, void* right )
{
return( -1 );
}
int
avl_dup_ok( void* left, void* right )
{
return( 0 );
}

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/* testavl.c - Test Tim Howes AVL code */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 1998-2003 The OpenLDAP Foundation.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
/* Portions Copyright (c) 1993 Regents of the University of Michigan.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and that due credit is given
* to the University of Michigan at Ann Arbor. The name of the University
* may not be used to endorse or promote products derived from this
* software without specific prior written permission. This software
* is provided ``as is'' without express or implied warranty.
*/
/* ACKNOWLEDGEMENTS:
* This work was originally developed by the University of Michigan
* (as part of U-MICH LDAP).
*/
#include "portable.h"
#include <stdio.h>
#include <ac/stdlib.h>
#include <ac/string.h>
#define AVL_INTERNAL
#define AVL_NONREENTRANT
#include "avl.h"
static void ravl_print LDAP_P(( Avlnode *root, int depth ));
static void myprint LDAP_P(( Avlnode *root ));
static int avl_strcmp LDAP_P(( const void *s, const void *t ));
int
main( int argc, char **argv )
{
Avlnode *tree = NULL;
char command[ 10 ];
char name[ 80 ];
char *p;
printf( "> " );
while ( fgets( command, sizeof( command ), stdin ) != NULL ) {
switch( *command ) {
case 'n': /* new tree */
( void ) avl_free( tree, free );
tree = NULL;
break;
case 'p': /* print */
( void ) myprint( tree );
break;
case 't': /* traverse with first, next */
#ifdef AVL_NONREENTRANT
printf( "***\n" );
for ( p = (char * ) avl_getfirst( tree );
p != NULL;
p = (char *) avl_getnext())
printf( "%s\n", p );
printf( "***\n" );
#else
printf( "*** reentrant interface not implemented ***" );
#endif
break;
case 'f': /* find */
printf( "data? " );
if ( fgets( name, sizeof( name ), stdin ) == NULL )
exit( EXIT_SUCCESS );
name[ strlen( name ) - 1 ] = '\0';
if ( (p = (char *) avl_find( tree, name, avl_strcmp ))
== NULL )
printf( "Not found.\n\n" );
else
printf( "%s\n\n", p );
break;
case 'i': /* insert */
printf( "data? " );
if ( fgets( name, sizeof( name ), stdin ) == NULL )
exit( EXIT_SUCCESS );
name[ strlen( name ) - 1 ] = '\0';
if ( avl_insert( &tree, strdup( name ), avl_strcmp,
avl_dup_error ) != 0 )
printf( "\nNot inserted!\n" );
break;
case 'd': /* delete */
printf( "data? " );
if ( fgets( name, sizeof( name ), stdin ) == NULL )
exit( EXIT_SUCCESS );
name[ strlen( name ) - 1 ] = '\0';
if ( avl_delete( &tree, name, avl_strcmp ) == NULL )
printf( "\nNot found!\n" );
break;
case 'q': /* quit */
exit( EXIT_SUCCESS );
break;
case '\n':
break;
default:
printf("Commands: insert, delete, print, new, quit\n");
}
printf( "> " );
}
return( 0 );
}
static void ravl_print( Avlnode *root, int depth )
{
int i;
if ( root == 0 )
return;
ravl_print( root->avl_right, depth+1 );
for ( i = 0; i < depth; i++ )
printf( " " );
printf( "%s %d\n", (char *) root->avl_data, root->avl_bf );
ravl_print( root->avl_left, depth+1 );
}
static void myprint( Avlnode *root )
{
printf( "********\n" );
if ( root == 0 )
printf( "\tNULL\n" );
else
ravl_print( root, 0 );
printf( "********\n" );
}
static int avl_strcmp( const void *s, const void *t )
{
return strcmp( s, t );
}