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/*
* The Spread Toolkit.
*
* The contents of this file are subject to the Spread Open-Source
* License, Version 1.0 (the ``License''); you may not use
* this file except in compliance with the License. You may obtain a
* copy of the License at:
*
* http://www.spread.org/license/
*
* or in the file ``license.txt'' found in this distribution.
*
* Software distributed under the License is distributed on an AS IS basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Creators of Spread are:
* Yair Amir, Michal Miskin-Amir, Jonathan Stanton.
*
* Copyright (C) 1993-2004 Spread Concepts LLC <spread@spreadconcepts.com>
*
* All Rights Reserved.
*
* Major Contributor(s):
* ---------------
* Cristina Nita-Rotaru crisn@cs.purdue.edu - group communication security.
* Theo Schlossnagle jesus@omniti.com - Perl, skiplists, autoconf.
* Dan Schoenblum dansch@cnds.jhu.edu - Java interface.
* John Schultz jschultz@cnds.jhu.edu - contribution to process group membership.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "skiplist_p.h"
#include "alarm.h"
#ifndef MIN
#define MIN(a,b) ((a<b)?(a):(b))
#endif
static int get_b_rand() {
static int ph=32; /* More bits than we will ever use */
static unsigned long randseq;
if(ph > 31) { /* Num bits in return of lrand48() */
ph=0;
randseq = get_rand();
}
ph++;
return ((randseq & (1 << (ph-1))) >> (ph-1));
}
void sli_init(Skiplist *sl) {
sl->compare = (SkiplistComparator)NULL;
sl->comparek = (SkiplistComparator)NULL;
sl->height=0;
sl->preheight=0;
sl->size=0;
sl->top = NULL;
sl->bottom = NULL;
sl->index = NULL;
}
static int indexing_comp(const void *a, const void *b)
{
void *ak = (void *) (((Skiplist *) a)->compare);
void *bk = (void *) (((Skiplist *) b)->compare);
assert(a);
assert(b);
if(ak<bk)
return -1;
if(ak>bk)
return 1;
return 0;
}
static int indexing_compk(const void *ak, const void *b)
{
void *bk = (void *) (((Skiplist *) b)->compare);
assert(b);
if(ak<bk)
return -1;
if(ak>bk)
return 1;
return 0;
}
void sl_init(Skiplist *sl) {
sli_init(sl);
sl->index = (Skiplist *)malloc(sizeof(Skiplist));
sli_init(sl->index);
sl_set_compare(sl->index, indexing_comp, indexing_compk);
}
void sl_set_compare(Skiplist *sl,
SkiplistComparator comp,
SkiplistComparator compk) {
if(sl->compare && sl->comparek) {
sl_add_index(sl, comp, compk);
} else {
sl->compare = comp;
sl->comparek = compk;
}
}
void sl_add_index(Skiplist *sl,
SkiplistComparator comp,
SkiplistComparator compk) {
struct skiplistnode *m;
Skiplist *ni;
int icount=0;
Alarm(SKIPLIST, "Adding index to %p\n", sl);
sl_find(sl->index, (void *)comp, &m);
if(m) return; /* Index already there! */
ni = (Skiplist *)malloc(sizeof(Skiplist));
sli_init(ni);
sl_set_compare(ni, comp, compk);
/* Build the new index... This can be expensive! */
m = sl_insert(sl->index, ni);
while(m->prev) m=m->prev, icount++;
for(m=sl_getlist(sl); m; sl_next(sl, &m)) {
int j=icount-1;
struct skiplistnode *nsln;
nsln = sl_insert(ni, m->data);
/* skip from main index down list */
while(j>0) m=m->nextindex, j--;
/* insert this node in the indexlist after m */
nsln->nextindex = m->nextindex;
if(m->nextindex) m->nextindex->previndex = nsln;
nsln->previndex = m;
m->nextindex = nsln;
}
}
struct skiplistnode *sl_getlist(Skiplist *sl) {
if(!sl->bottom) return NULL;
return sl->bottom->next;
}
void *sl_find(Skiplist *sl,
void *data,
struct skiplistnode **iter) {
void *ret;
if(!sl->compare) return 0;
ret = sl_find_compare(sl, data, iter, sl->compare);
return ret;
}
void *sl_find_compare(Skiplist *sli,
void *data,
struct skiplistnode **iter,
SkiplistComparator comp) {
struct skiplistnode *m = NULL;
Skiplist *sl;
if(comp==sli->compare || !sli->index) {
sl = sli;
} else {
sl_find(sli->index, (void *)comp, &m);
assert(m);
sl=m->data;
}
sli_find_compare(sl, data, iter, sl->comparek);
return (*iter)?((*iter)->data):(*iter);
}
int sli_find_compare(Skiplist *sl,
void *data,
struct skiplistnode **ret,
SkiplistComparator comp) {
struct skiplistnode *m = NULL;
int count=0;
m = sl->top;
while(m) {
int compared = 1;
if(m->next) compared=comp(data, m->next->data);
if(compared == 0) {
#ifdef SL_DEBUG
Alarm(SKIPLIST, "Looking -- found in %d steps\n", count);
#endif
m=m->next;
while(m->down) m=m->down;
*ret = m;
return count;
}
if((m->next == NULL) || (compared<0))
m = m->down, count++;
else
m = m->next, count++;
}
#ifdef SL_DEBUG
Alarm(SKIPLIST, "Looking -- not found in %d steps\n", count);
#endif
*ret = NULL;
return count;
}
void *sl_next(Skiplist *sl, struct skiplistnode **iter) {
if(!*iter) return NULL;
*iter = (*iter)->next;
return (*iter)?((*iter)->data):NULL;
}
void *sl_previous(Skiplist *sl, struct skiplistnode **iter) {
if(!*iter) return NULL;
*iter = (*iter)->prev;
return (*iter)?((*iter)->data):NULL;
}
struct skiplistnode *sl_insert(Skiplist *sl,
void *data) {
if(!sl->compare) return 0;
return sl_insert_compare(sl, data, sl->compare);
}
struct skiplistnode *sl_insert_compare(Skiplist *sl,
void *data,
SkiplistComparator comp) {
struct skiplistnode *m, *p, *tmp, *ret, **stack;
int nh=1, ch, stacki;
ret = NULL;
/*sl_print_struct(sl, "BI: ");*/
if(!sl->top) {
sl->height = 1;
sl->topend = sl->bottomend = sl->top = sl->bottom =
(struct skiplistnode *)malloc(sizeof(struct skiplistnode));
assert(sl->top);
sl->top->next = sl->top->data = sl->top->prev =
sl->top->up = sl->top->down =
sl->top->nextindex = sl->top->previndex = NULL;
sl->top->sl = sl;
}
if(sl->preheight) {
while(nh < sl->preheight && get_b_rand()) nh++;
} else {
while(nh <= sl->height && get_b_rand()) nh++;
}
/* Now we have the new height at which we wish to insert our new node */
/* Let us make sure that our tree is a least that tall (grow if necessary)*/
for(;sl->height<nh;sl->height++) {
sl->top->up =
(struct skiplistnode *)malloc(sizeof(struct skiplistnode));
assert(sl->top->up);
sl->top->up->down = sl->top;
sl->top = sl->topend = sl->top->up;
sl->top->prev = sl->top->next = sl->top->nextindex =
sl->top->previndex = sl->top->up = NULL;
sl->top->data = NULL;
sl->top->sl = sl;
}
ch = sl->height;
/* Find the node (or node after which we would insert) */
/* Keep a stack to pop back through for insertion */
m = sl->top;
stack = (struct skiplistnode **)malloc(sizeof(struct skiplistnode *)*(nh));
stacki=0;
while(m) {
int compared=-1;
if(m->next) compared=comp(data, m->next->data);
if(compared == 0) {
free(stack);
return 0;
}
if((m->next == NULL) || (compared<0)) {
/* FIXME: This if ch<=nh test looks unnecessary. ch==nh at beginning of while(m)
*/
if(ch<=nh) {
/* push on stack */
stack[stacki++] = m;
}
m = m->down;
ch--;
} else {
m = m->next;
}
}
/* Pop the stack and insert nodes */
p = tmp = NULL;
for(;stacki>0;stacki--) {
m = stack[stacki-1];
tmp = (struct skiplistnode *)malloc(sizeof(struct skiplistnode));
tmp->next = m->next;
if(m->next) m->next->prev=tmp;
tmp->prev = m;
tmp->up = NULL;
tmp->nextindex = tmp->previndex = NULL;
tmp->down = p;
if(p) p->up=tmp;
tmp->data = data;
tmp->sl = sl;
m->next = tmp;
/* This sets ret to the bottom-most node we are inserting */
if(!p)
{
ret=tmp;
sl->size++;
}
p = tmp;
}
free(stack);
if(tmp && (tmp->prev == sl->topend)) {
/* The last element on the top row is the new inserted one */
sl->topend = tmp;
}
if(ret && (ret->prev == sl->bottomend)) {
/* The last element on the bottom row is the new inserted one */
sl->bottomend = ret;
}
if(sl->index != NULL) {
/* this is a external insertion, we must insert into each index as well */
struct skiplistnode *p, *ni, *li;
li=ret;
for(p = sl_getlist(sl->index); p; sl_next(sl->index, &p)) {
ni = sl_insert((Skiplist *)p->data, ret->data);
assert(ni);
Alarm(SKIPLIST, "Adding %p to index %p\n", ret->data, p->data);
li->nextindex = ni;
ni->previndex = li;
li = ni;
}
}
/* JRS: move size increment above to where node is inserted
else {
sl->size++;
}
*/
/*sl_print_struct(sl, "AI: ");*/
return ret;
}
struct skiplistnode *sl_append(Skiplist *sl, void *data) {
return sl_insert(sl, data);
}
#if 0
struct skiplistnode *sl_append(Skiplist *sl, void *data) {
int nh=1, ch, compared;
struct skiplistnode *lastnode, *nodeago;
if(sl->bottomend != sl->bottom) {
compared=sl->compare(data, sl->bottomend->prev->data);
/* If it doesn't belong at the end, then fail */
if(compared<=0) return NULL;
}
if(sl->preheight) {
while(nh < sl->preheight && get_b_rand()) nh++;
} else {
while(nh <= sl->height && get_b_rand()) nh++;
}
/* Now we have the new hieght at which we wish to insert our new node */
/* Let us make sure that our tree is a least that tall (grow if necessary)*/
lastnode = sl->bottomend;
nodeago = NULL;
if(!lastnode) return sl_insert(sl, data);
for(;sl->height<nh;sl->height++) {
assert(sl->top);
sl->top->up =
(struct skiplistnode *)malloc(sizeof(struct skiplistnode));
sl->top->up->down = sl->top;
sl->top = sl->topend = sl->top->up;
sl->top->prev = sl->top->next = sl->top->nextindex =
sl->top->previndex = NULL;
sl->top->data = NULL;
sl->top->sl = sl;
}
ch = sl->height;
while(nh) {
struct skiplistnode *anode;
anode =
(struct skiplistnode *)malloc(sizeof(struct skiplistnode));
anode->next = lastnode;
anode->prev = lastnode->prev;
anode->up = NULL;
anode->down = nodeago;
/* If this the bottom, we are appending, so bottomend should change */
if(!nodeago) sl->bottomend = anode;
if(lastnode->prev) {
if(lastnode == sl->bottom)
sl->bottom = anode;
else if (lastnode == sl->top)
sl->top = anode;
}
nodeago = anode;
lastnode = lastnode->up;
nh--;
}
sl->size++;
return(nodeago);
}
#endif
Skiplist *sl_concat(Skiplist *sl1, Skiplist *sl2) {
/* Check integrity! */
Skiplist temp;
struct skiplistnode *b2;
if(sl1->bottomend == NULL || sl1->bottomend->prev == NULL) {
sl_remove_all(sl1, free);
temp = *sl1;
*sl1 = *sl2;
*sl2 = temp;
/* swap them so that sl2 can be freed normally upon return. */
return sl1;
}
if(sl2->bottom == NULL || sl2->bottom->next == NULL) {
sl_remove_all(sl2, free);
return sl1;
}
b2 = sl_getlist(sl2);
while(b2) {
sl_insert(sl1, b2->data);
sl_next(sl2, &b2);
}
sl_remove_all(sl2, NULL);
return sl1;
}
#if 0
Skiplist *sl_concat(Skiplist *sl1, Skiplist *sl2) {
/* Check integrity! */
int compared, eheight;
Skiplist temp;
struct skiplistnode *lbottom, *lbottomend, *b1, *e1, *b2, *e2;
if(sl1->bottomend == NULL || sl1->bottomend->prev == NULL) {
sl_remove_all(sl1, free);
temp = *sl1;
*sl1 = *sl2;
*sl2 = temp;
/* swap them so that sl2 can be freed normally upon return. */
return sl1;
}
if(sl2->bottom == NULL || sl2->bottom->next == NULL) {
sl_remove_all(sl2, free);
return sl1;
}
compared = sl1->compare(sl1->bottomend->prev->data, sl2->bottom->data);
/* If it doesn't belong at the end, then fail */
if(compared<=0) return NULL;
/* OK now append sl2 onto sl1 */
lbottom = lbottomend = NULL;
eheight = MIN(sl1->height, sl2->height);
b1 = sl1->bottom; e1 = sl1->bottomend;
b2 = sl2->bottom; e2 = sl2->bottomend;
while(eheight) {
e1->prev->next = b2;
b2->prev = e1->prev->next;
e2->prev->next = e1;
e1->prev = e2->prev;
e2->prev = NULL;
b2 = e2;
b1->down = lbottom;
e1->down = lbottomend;
if(lbottom) lbottom->up = b1;
if(lbottomend) lbottomend->up = e1;
lbottom = b1;
lbottomend = e1;
}
/* Take the top of the longer one (if it is sl2) and make it sl1's */
if(sl2->height > sl1->height) {
b1->up = b2->up;
e1->up = e2->up;
b1->up->down = b1;
e1->up->down = e1;
sl1->height = sl2->height;
sl1->top = sl2->top;
sl1->topend = sl2->topend;
}
/* move the top pointer to here if it isn't there already */
sl2->top = sl2->topend = b2;
sl2->top->up = NULL; /* If it isn't already */
sl1->size += sl2->size;
sl_remove_all(sl2, free);
return sl1;
}
#endif
int sl_remove(Skiplist *sl,
void *data, FreeFunc myfree) {
if(!sl->compare) return 0;
return sl_remove_compare(sl, data, myfree, sl->comparek);
}
void sl_print_struct(Skiplist *sl, char *prefix, char *(*printdata)(void *)) {
struct skiplistnode *p, *q;
Alarm(SKIPLIST, "Skiplist Structure (height: %d)\n", sl->height);
p = sl->bottom;
while(p) {
q = p;
Alarm(SKIPLIST, prefix);
while(q) {
Alarm(SKIPLIST, "%6s ", printdata(q->data));
q=q->up;
}
Alarm(SKIPLIST, "\n");
p=p->next;
}
}
int sli_remove(Skiplist *sl, struct skiplistnode *m, FreeFunc myfree) {
struct skiplistnode *p;
if(!m) return 0;
if(m->nextindex) sli_remove(m->nextindex->sl, m->nextindex, NULL);
else sl->size--;
/*sl_print_struct(sl, "BR:");*/
while(m->up) m=m->up;
while(m) {
p=m;
p->prev->next = p->next; /* take me out of the list */
if(p->next) p->next->prev = p->prev; /* take me out of the list */
m=m->down;
/* This only frees the actual data in the bottom one */
if(!m && myfree && p->data) myfree(p->data);
free(p);
}
while(sl->top && sl->top->next == NULL) {
/* While the row is empty and we are not on the bottom row */
p = sl->top;
sl->top = sl->top->down; /* Move top down one */
if(sl->top) sl->top->up = NULL; /* Make it think its the top */
free(p);
sl->height--;
}
if(!sl->top) sl->bottom = NULL;
assert(sl->height>=0);
/*sl_print_struct(sl, "AR: ");*/
return sl->height;
}
int sl_remove_compare(Skiplist *sli,
void *data,
FreeFunc myfree, SkiplistComparator comp) {
struct skiplistnode *m;
Skiplist *sl;
if(comp==sli->comparek || !sli->index) {
sl = sli;
} else {
sl_find(sli->index, (void *)comp, &m);
assert(m);
sl=m->data;
}
sli_find_compare(sl, data, &m, comp);
if (!m) return( 0 );
while(m->previndex) m=m->previndex;
return sli_remove(sl, m, myfree);
}
void sl_remove_all(Skiplist *sl, FreeFunc myfree) {
/* This must remove even the place holder nodes (bottom though top)
because we specify in the API that one can free the Skiplist after
making this call without memory leaks */
struct skiplistnode *m, *p, *u;
m=sl->bottom;
while(m) {
p = m->next;
if(myfree && p && p->data) myfree(p->data);
while(m) {
u = m->up;
free(m);
m=u;
}
m = p;
}
sl->top = sl->bottom = NULL;
sl->height = 0;
sl->size = 0;
}
void sli_destruct_free(Skiplist *sl, FreeFunc myfree) {
sl_remove_all(sl, NULL);
free(sl);
}
void sl_destruct(Skiplist *sl, FreeFunc myfree) {
if(sl->index) {
sl_remove_all(sl->index, (FreeFunc)sli_destruct_free);
free(sl->index);
}
sl_remove_all(sl, myfree);
}
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