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Add threaded AVL functions
This commit is contained in:
Howard Chu
parent
b6e38a12bf
commit
cbb86907a2
@ -29,13 +29,13 @@ XLIBS = $(LIBRARY) $(LDAP_LIBLBER_LA)
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SRCS = base64.c csn.c entropy.c sasl.c signal.c hash.c passfile.c \
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md5.c passwd.c sha1.c getpass.c lockf.c utils.c uuid.c sockpair.c \
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avl.c ldif.c fetch.c \
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avl.c tavl.c ldif.c fetch.c \
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testavl.c \
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@LIBSRCS@ $(@PLAT@_SRCS)
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OBJS = base64.o csn.o entropy.o sasl.o signal.o hash.o passfile.o \
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md5.o passwd.o sha1.o getpass.o lockf.o utils.o uuid.o sockpair.o \
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avl.o ldif.o fetch.o \
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avl.o tavl.o ldif.o fetch.o \
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@LIBOBJS@ $(@PLAT@_OBJS)
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testavl: $(XLIBS) testavl.o
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431
libraries/liblutil/tavl.c
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431
libraries/liblutil/tavl.c
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@ -0,0 +1,431 @@
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/* avl.c - routines to implement an avl tree */
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/* $OpenLDAP$ */
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/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
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*
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* Copyright 2005 The OpenLDAP Foundation.
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* Portions Copyright (c) 2005 by Howard Chu, Symas Corp.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted only as authorized by the OpenLDAP
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* Public License.
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*
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* A copy of this license is available in the file LICENSE in the
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* top-level directory of the distribution or, alternatively, at
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* <http://www.OpenLDAP.org/license.html>.
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*/
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/* ACKNOWLEDGEMENTS:
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* This work was initially developed by Howard Chu for inclusion
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* in OpenLDAP software.
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*/
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#include "portable.h"
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#include <stdio.h>
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#include <ac/stdlib.h>
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#ifdef CSRIMALLOC
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#define ber_memalloc malloc
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#define ber_memrealloc realloc
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#define ber_memfree free
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#else
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#include "lber.h"
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#endif
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#define AVL_INTERNAL
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#include "avl.h"
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static const int avl_bfs[] = {LH, RH};
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/*
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* Threaded AVL trees - for fast in-order traversal of nodes.
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*/
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/*
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* tavl_insert -- insert a node containing data data into the avl tree
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* with root root. fcmp is a function to call to compare the data portion
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* of two nodes. it should take two arguments and return <, >, or == 0,
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* depending on whether its first argument is <, >, or == its second
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* argument (like strcmp, e.g.). fdup is a function to call when a duplicate
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* node is inserted. it should return 0, or -1 and its return value
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* will be the return value from avl_insert in the case of a duplicate node.
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* the function will be called with the original node's data as its first
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* argument and with the incoming duplicate node's data as its second
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* argument. this could be used, for example, to keep a count with each
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* node.
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*
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* NOTE: this routine may malloc memory
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*/
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int
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tavl_insert( Avlnode ** root, void *data, AVL_CMP fcmp, AVL_DUP fdup )
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{
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Avlnode *t, *p, *s, *q, *r;
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int a, cmp, ncmp;
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if ( *root == NULL ) {
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if (( r = (Avlnode *) ber_memalloc( sizeof( Avlnode ))) == NULL ) {
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return( -1 );
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}
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r->avl_link[0] = r->avl_link[1] = NULL;
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r->avl_data = data;
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r->avl_bf = EH;
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r->avl_bits[0] = r->avl_bits[1] = AVL_THREAD;
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*root = r;
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return( 0 );
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}
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t = NULL;
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s = p = *root;
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/* find insertion point */
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while (1) {
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cmp = fcmp( data, p->avl_data );
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if ( cmp == 0 )
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return (*fdup)( p->avl_data, data );
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cmp = (cmp > 0);
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q = avl_child( p, cmp );
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if (q == NULL) {
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/* insert */
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if (( q = (Avlnode *) ber_memalloc( sizeof( Avlnode ))) == NULL ) {
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return( -1 );
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}
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q->avl_link[cmp] = p->avl_link[cmp];
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q->avl_link[!cmp] = p;
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q->avl_data = data;
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q->avl_bf = EH;
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q->avl_bits[0] = q->avl_bits[1] = AVL_THREAD;
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p->avl_link[cmp] = q;
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p->avl_bits[cmp] = AVL_CHILD;
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break;
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} else if ( q->avl_bf ) {
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t = p;
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s = q;
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}
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p = q;
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}
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/* adjust balance factors */
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cmp = fcmp( data, s->avl_data ) > 0;
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r = p = s->avl_link[cmp];
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a = avl_bfs[cmp];
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while ( p != q ) {
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cmp = fcmp( data, p->avl_data ) > 0;
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p->avl_bf = avl_bfs[cmp];
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p = p->avl_link[cmp];
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}
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/* checks and balances */
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if ( s->avl_bf == EH ) {
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s->avl_bf = a;
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return 0;
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} else if ( s->avl_bf == -a ) {
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s->avl_bf = EH;
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return 0;
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} else if ( s->avl_bf == a ) {
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cmp = (a > 0);
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ncmp = !cmp;
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if ( r->avl_bf == a ) {
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/* single rotation */
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p = r;
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if ( r->avl_bits[ncmp] == AVL_THREAD ) {
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r->avl_bits[ncmp] = AVL_CHILD;
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s->avl_bits[cmp] = AVL_THREAD;
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} else {
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s->avl_link[cmp] = r->avl_link[ncmp];
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r->avl_link[ncmp] = s;
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}
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s->avl_bf = 0;
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r->avl_bf = 0;
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} else if ( r->avl_bf == -a ) {
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/* double rotation */
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p = r->avl_link[ncmp];
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if ( p->avl_bits[cmp] == AVL_THREAD ) {
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p->avl_bits[cmp] = AVL_CHILD;
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r->avl_bits[ncmp] = AVL_THREAD;
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} else {
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r->avl_link[ncmp] = p->avl_link[cmp];
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p->avl_link[cmp] = r;
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}
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if ( p->avl_bits[ncmp] == AVL_THREAD ) {
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p->avl_bits[ncmp] = AVL_CHILD;
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s->avl_link[cmp] = p;
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s->avl_bits[cmp] = AVL_THREAD;
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} else {
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s->avl_link[cmp] = p->avl_link[ncmp];
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p->avl_link[ncmp] = s;
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}
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if ( p->avl_bf == a ) {
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s->avl_bf = -a;
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r->avl_bf = 0;
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} else if ( p->avl_bf == -a ) {
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s->avl_bf = 0;
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r->avl_bf = a;
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} else {
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s->avl_bf = 0;
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r->avl_bf = 0;
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}
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p->avl_bf = 0;
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}
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/* Update parent */
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if ( t == NULL )
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*root = p;
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else if ( s == t->avl_right )
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t->avl_right = p;
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else
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t->avl_left = p;
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}
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return 0;
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}
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void*
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tavl_delete( Avlnode **root, void* data, AVL_CMP fcmp )
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{
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Avlnode *p, *q, *r, *top;
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int side, side_bf, shorter, cmp;
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/* parent stack */
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Avlnode *pptr[sizeof(void *)*8];
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unsigned char pdir[sizeof(void *)*8];
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int depth = 0;
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if ( *root == NULL )
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return NULL;
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p = *root;
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while (1) {
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cmp = fcmp( data, p->avl_data );
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if ( !cmp )
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break;
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cmp = ( cmp > 0 );
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pdir[depth] = cmp;
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pptr[depth++] = p;
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p = avl_child( p, cmp );
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if ( p == NULL )
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return NULL;
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}
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/* If this node has two children, swap so we are deleting a node with
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* at most one child.
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*/
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if ( p->avl_bits[0] == AVL_CHILD && p->avl_bits[1] == AVL_CHILD &&
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p->avl_link[0] && p->avl_link[1] ) {
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void *temp;
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/* find the immediate predecessor <q> */
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q = p->avl_link[0];
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pdir[depth] = 0;
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pptr[depth++] = p;
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while (q->avl_bits[1] == AVL_CHILD && q->avl_link[1]) {
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pdir[depth] = 1;
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pptr[depth++] = q;
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q = q->avl_link[1];
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}
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/* swap */
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temp = p->avl_data;
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p->avl_data = q->avl_data;
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q->avl_data = temp;
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p = q;
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}
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/* now <p> has at most one child, get it */
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if ( p->avl_link[0] && p->avl_bits[0] == AVL_CHILD ) {
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q = p->avl_link[0];
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} else if ( p->avl_link[1] && p->avl_bits[1] == AVL_CHILD ) {
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q = p->avl_link[1];
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} else {
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q = NULL;
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}
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data = p->avl_data;
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ber_memfree( p );
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if ( !depth ) {
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*root = q;
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return data;
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}
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/* set the child into p's parent */
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depth--;
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side = pdir[depth];
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p = pptr[depth];
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p->avl_link[side] = q;
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side_bf = avl_bfs[side];
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top = NULL;
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/* Update child thread */
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if ( q ) {
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while ( q->avl_bits[!side] == AVL_CHILD )
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q = q->avl_link[!side];
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q->avl_link[!side] = p;
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}
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shorter = 1;
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while ( shorter ) {
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/* case 1: height unchanged */
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if ( p->avl_bf == EH ) {
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/* Tree is now heavier on opposite side */
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p->avl_bf = avl_bfs[!side];
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shorter = 0;
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} else if ( p->avl_bf == side_bf ) {
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/* case 2: taller subtree shortened, height reduced */
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p->avl_bf = EH;
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} else {
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/* case 3: shorter subtree shortened */
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if ( depth )
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top = pptr[depth-1]; /* p->parent; */
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else
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top = NULL;
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/* set <q> to the taller of the two subtrees of <p> */
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q = p->avl_link[!side];
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if ( q->avl_bf == EH ) {
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/* case 3a: height unchanged, single rotate */
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if ( q->avl_bits[side] == AVL_THREAD ) {
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q->avl_bits[side] = AVL_CHILD;
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p->avl_bits[!side] = AVL_THREAD;
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} else {
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p->avl_link[!side] = q->avl_link[side];
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q->avl_link[side] = p;
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}
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shorter = 0;
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q->avl_bf = side_bf;
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p->avl_bf = (- side_bf);
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} else if ( q->avl_bf == p->avl_bf ) {
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/* case 3b: height reduced, single rotate */
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if ( q->avl_bits[side] == AVL_THREAD ) {
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q->avl_bits[side] = AVL_CHILD;
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p->avl_bits[!side] = AVL_THREAD;
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} else {
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p->avl_link[!side] = q->avl_link[side];
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q->avl_link[side] = p;
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}
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shorter = 1;
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q->avl_bf = EH;
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p->avl_bf = EH;
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} else {
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/* case 3c: height reduced, balance factors opposite */
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r = q->avl_link[side];
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if ( r->avl_bits[!side] == AVL_THREAD ) {
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r->avl_bits[!side] = AVL_CHILD;
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q->avl_bits[side] = AVL_THREAD;
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} else {
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q->avl_link[side] = r->avl_link[!side];
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r->avl_link[!side] = q;
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}
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if ( r->avl_bits[side] == AVL_THREAD ) {
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r->avl_bits[side] = AVL_CHILD;
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p->avl_bits[!side] = AVL_THREAD;
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p->avl_link[!side] = r;
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} else {
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p->avl_link[!side] = r->avl_link[side];
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r->avl_link[side] = p;
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}
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if ( r->avl_bf == side_bf ) {
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q->avl_bf = (- side_bf);
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p->avl_bf = EH;
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} else if ( r->avl_bf == (- side_bf)) {
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q->avl_bf = EH;
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p->avl_bf = side_bf;
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} else {
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q->avl_bf = EH;
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p->avl_bf = EH;
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}
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r->avl_bf = EH;
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q = r;
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}
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/* a rotation has caused <q> (or <r> in case 3c) to become
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* the root. let <p>'s former parent know this.
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*/
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if ( top == NULL ) {
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*root = q;
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} else if (top->avl_link[0] == p) {
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top->avl_link[0] = q;
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} else {
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top->avl_link[1] = q;
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}
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/* end case 3 */
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p = q;
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}
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if ( !depth )
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break;
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depth--;
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p = pptr[depth];
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side = pdir[depth];
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side_bf = avl_bfs[side];
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} /* end while(shorter) */
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return data;
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}
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/*
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* tavl_free -- traverse avltree root, freeing the memory it is using.
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* the dfree() is called to free the data portion of each node. The
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* number of items actually freed is returned.
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*/
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int
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tavl_free( Avlnode *root, AVL_FREE dfree )
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{
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int nleft, nright;
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if ( root == 0 )
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return( 0 );
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nleft = tavl_free( avl_lchild( root ), dfree );
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nright = tavl_free( avl_rchild( root ), dfree );
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if ( dfree )
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(*dfree)( root->avl_data );
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ber_memfree( root );
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return( nleft + nright + 1 );
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}
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/*
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* tavl_find -- search avltree root for a node with data data. the function
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* cmp is used to compare things. it is called with data as its first arg
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* and the current node data as its second. it should return 0 if they match,
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* < 0 if arg1 is less than arg2 and > 0 if arg1 is greater than arg2.
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*/
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Avlnode *
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tavl_find2( Avlnode *root, const void *data, AVL_CMP fcmp )
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{
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int cmp;
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while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
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if ( cmp < 0 )
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root = avl_lchild( root );
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else
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root = avl_rchild( root );
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}
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return root;
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}
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void*
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tavl_find( Avlnode *root, const void* data, AVL_CMP fcmp )
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{
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int cmp;
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while ( root != 0 && (cmp = (*fcmp)( data, root->avl_data )) != 0 ) {
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if ( cmp < 0 )
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root = avl_lchild( root );
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else
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root = avl_rchild( root );
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}
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return( root ? root->avl_data : 0 );
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}
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