651 lines
18 KiB
C
651 lines
18 KiB
C
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* Modified to use APR and APR pools.
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* TODO: Is malloc() better? Will long running skiplists grow too much?
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* Keep the skiplist_alloc() and skiplist_free() until we know
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* Yeah, if using pools it means some bogus cycles for checks
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* (and an useless function call for skiplist_free) which we
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* can removed if/when needed.
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*/
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#include "apr_skiplist.h"
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struct apr_skiplist {
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apr_skiplist_compare compare;
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apr_skiplist_compare comparek;
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int height;
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int preheight;
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int size;
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apr_skiplistnode *top;
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apr_skiplistnode *bottom;
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/* These two are needed for appending */
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apr_skiplistnode *topend;
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apr_skiplistnode *bottomend;
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apr_skiplist *index;
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apr_array_header_t *memlist;
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apr_pool_t *pool;
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};
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struct apr_skiplistnode {
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void *data;
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apr_skiplistnode *next;
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apr_skiplistnode *prev;
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apr_skiplistnode *down;
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apr_skiplistnode *up;
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apr_skiplistnode *previndex;
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apr_skiplistnode *nextindex;
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apr_skiplist *sl;
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};
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#ifndef MIN
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#define MIN(a,b) ((a<b)?(a):(b))
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#endif
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static int get_b_rand(void)
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{
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static int ph = 32; /* More bits than we will ever use */
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static apr_uint32_t randseq;
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if (ph > 31) { /* Num bits in return of rand() */
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ph = 0;
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randseq = (apr_uint32_t) rand();
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}
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ph++;
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return ((randseq & (1 << (ph - 1))) >> (ph - 1));
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}
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typedef struct {
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size_t size;
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apr_array_header_t *list;
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} memlist_t;
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typedef struct {
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void *ptr;
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char inuse;
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} chunk_t;
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APR_DECLARE(void *) apr_skiplist_alloc(apr_skiplist *sl, size_t size)
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{
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if (sl->pool) {
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void *ptr;
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int found_size = 0;
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int i;
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chunk_t *newchunk;
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memlist_t *memlist = (memlist_t *)sl->memlist->elts;
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for (i = 0; i < sl->memlist->nelts; i++) {
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if (memlist->size == size) {
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int j;
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chunk_t *chunk = (chunk_t *)memlist->list->elts;
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found_size = 1;
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for (j = 0; j < memlist->list->nelts; j++) {
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if (!chunk->inuse) {
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chunk->inuse = 1;
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return chunk->ptr;
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}
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chunk++;
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}
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break; /* no free of this size; punt */
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}
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memlist++;
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}
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/* no free chunks */
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ptr = apr_pcalloc(sl->pool, size);
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if (!ptr) {
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return ptr;
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}
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/*
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* is this a new sized chunk? If so, we need to create a new
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* array of them. Otherwise, re-use what we already have.
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*/
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if (!found_size) {
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memlist = apr_array_push(sl->memlist);
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memlist->size = size;
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memlist->list = apr_array_make(sl->pool, 20, sizeof(chunk_t));
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}
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newchunk = apr_array_push(memlist->list);
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newchunk->ptr = ptr;
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newchunk->inuse = 1;
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return ptr;
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}
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else {
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return calloc(1, size);
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}
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}
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APR_DECLARE(void) apr_skiplist_free(apr_skiplist *sl, void *mem)
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{
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if (!sl->pool) {
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free(mem);
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}
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else {
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int i;
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memlist_t *memlist = (memlist_t *)sl->memlist->elts;
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for (i = 0; i < sl->memlist->nelts; i++) {
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int j;
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chunk_t *chunk = (chunk_t *)memlist->list->elts;
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for (j = 0; j < memlist->list->nelts; j++) {
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if (chunk->ptr == mem) {
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chunk->inuse = 0;
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return;
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}
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chunk++;
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}
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memlist++;
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}
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}
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}
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static apr_status_t skiplisti_init(apr_skiplist **s, apr_pool_t *p)
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{
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apr_skiplist *sl;
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if (p) {
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sl = apr_pcalloc(p, sizeof(apr_skiplist));
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sl->memlist = apr_array_make(p, 20, sizeof(memlist_t));
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}
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else {
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sl = calloc(1, sizeof(apr_skiplist));
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}
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#if 0
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sl->compare = (apr_skiplist_compare) NULL;
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sl->comparek = (apr_skiplist_compare) NULL;
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sl->height = 0;
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sl->preheight = 0;
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sl->size = 0;
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sl->top = NULL;
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sl->bottom = NULL;
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sl->index = NULL;
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#endif
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sl->pool = p;
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*s = sl;
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return APR_SUCCESS;
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}
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static int indexing_comp(void *a, void *b)
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{
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void *ac = (void *) (((apr_skiplist *) a)->compare);
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void *bc = (void *) (((apr_skiplist *) b)->compare);
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return ((ac < bc) ? -1 : ((ac > bc) ? 1 : 0));
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}
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static int indexing_compk(void *ac, void *b)
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{
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void *bc = (void *) (((apr_skiplist *) b)->compare);
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return ((ac < bc) ? -1 : ((ac > bc) ? 1 : 0));
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}
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APR_DECLARE(apr_status_t) apr_skiplist_init(apr_skiplist **s, apr_pool_t *p)
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{
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apr_skiplist *sl;
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skiplisti_init(s, p);
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sl = *s;
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skiplisti_init(&(sl->index), p);
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apr_skiplist_set_compare(sl->index, indexing_comp, indexing_compk);
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return APR_SUCCESS;
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}
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APR_DECLARE(void) apr_skiplist_set_compare(apr_skiplist *sl,
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apr_skiplist_compare comp,
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apr_skiplist_compare compk)
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{
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if (sl->compare && sl->comparek) {
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apr_skiplist_add_index(sl, comp, compk);
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}
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else {
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sl->compare = comp;
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sl->comparek = compk;
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}
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}
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APR_DECLARE(void) apr_skiplist_add_index(apr_skiplist *sl,
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apr_skiplist_compare comp,
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apr_skiplist_compare compk)
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{
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apr_skiplistnode *m;
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apr_skiplist *ni;
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int icount = 0;
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apr_skiplist_find(sl->index, (void *)comp, &m);
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if (m) {
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return; /* Index already there! */
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}
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skiplisti_init(&ni, sl->pool);
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apr_skiplist_set_compare(ni, comp, compk);
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/* Build the new index... This can be expensive! */
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m = apr_skiplist_insert(sl->index, ni);
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while (m->prev) {
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m = m->prev;
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icount++;
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}
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for (m = apr_skiplist_getlist(sl); m; apr_skiplist_next(sl, &m)) {
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int j = icount - 1;
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apr_skiplistnode *nsln;
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nsln = apr_skiplist_insert(ni, m->data);
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/* skip from main index down list */
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while (j > 0) {
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m = m->nextindex;
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j--;
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}
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/* insert this node in the indexlist after m */
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nsln->nextindex = m->nextindex;
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if (m->nextindex) {
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m->nextindex->previndex = nsln;
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}
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nsln->previndex = m;
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m->nextindex = nsln;
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}
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}
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APR_DECLARE(apr_skiplistnode *) apr_skiplist_getlist(apr_skiplist *sl)
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{
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if (!sl->bottom) {
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return NULL;
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}
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return sl->bottom->next;
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}
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APR_DECLARE(void *) apr_skiplist_find(apr_skiplist *sl, void *data, apr_skiplistnode **iter)
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{
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void *ret;
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apr_skiplistnode *aiter;
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if (!sl->compare) {
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return 0;
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}
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if (iter) {
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ret = apr_skiplist_find_compare(sl, data, iter, sl->compare);
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}
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else {
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ret = apr_skiplist_find_compare(sl, data, &aiter, sl->compare);
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}
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return ret;
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}
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static int skiplisti_find_compare(apr_skiplist *sl, void *data,
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apr_skiplistnode **ret,
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apr_skiplist_compare comp)
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{
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apr_skiplistnode *m = NULL;
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int count = 0;
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m = sl->top;
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while (m) {
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int compared;
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compared = (m->next) ? comp(data, m->next->data) : -1;
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if (compared == 0) {
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m = m->next;
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while (m->down) {
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m = m->down;
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}
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*ret = m;
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return count;
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}
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if ((m->next == NULL) || (compared < 0)) {
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m = m->down;
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count++;
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}
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else {
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m = m->next;
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count++;
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}
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}
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*ret = NULL;
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return count;
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}
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APR_DECLARE(void *) apr_skiplist_find_compare(apr_skiplist *sli, void *data,
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apr_skiplistnode **iter,
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apr_skiplist_compare comp)
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{
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apr_skiplistnode *m = NULL;
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apr_skiplist *sl;
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if (comp == sli->compare || !sli->index) {
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sl = sli;
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}
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else {
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apr_skiplist_find(sli->index, (void *)comp, &m);
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sl = (apr_skiplist *) m->data;
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}
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skiplisti_find_compare(sl, data, iter, sl->comparek);
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return (iter && *iter) ? ((*iter)->data) : NULL;
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}
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APR_DECLARE(void *) apr_skiplist_next(apr_skiplist *sl, apr_skiplistnode **iter)
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{
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if (!*iter) {
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return NULL;
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}
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*iter = (*iter)->next;
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return (*iter) ? ((*iter)->data) : NULL;
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}
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APR_DECLARE(void *) apr_skiplist_previous(apr_skiplist *sl, apr_skiplistnode **iter)
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{
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if (!*iter) {
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return NULL;
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}
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*iter = (*iter)->prev;
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return (*iter) ? ((*iter)->data) : NULL;
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}
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APR_DECLARE(apr_skiplistnode *) apr_skiplist_insert(apr_skiplist *sl, void *data)
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{
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if (!sl->compare) {
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return 0;
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}
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return apr_skiplist_insert_compare(sl, data, sl->compare);
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}
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APR_DECLARE(apr_skiplistnode *) apr_skiplist_insert_compare(apr_skiplist *sl, void *data,
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apr_skiplist_compare comp)
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{
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apr_skiplistnode *m, *p, *tmp, *ret = NULL, **stack;
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int nh = 1, ch, stacki;
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if (!sl->top) {
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sl->height = 1;
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sl->topend = sl->bottomend = sl->top = sl->bottom =
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(apr_skiplistnode *)apr_skiplist_alloc(sl, sizeof(apr_skiplistnode));
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#if 0
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sl->top->next = (apr_skiplistnode *)NULL;
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sl->top->data = (apr_skiplistnode *)NULL;
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sl->top->prev = (apr_skiplistnode *)NULL;
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sl->top->up = (apr_skiplistnode *)NULL;
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sl->top->down = (apr_skiplistnode *)NULL;
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sl->top->nextindex = (apr_skiplistnode *)NULL;
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sl->top->previndex = (apr_skiplistnode *)NULL;
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#endif
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sl->top->sl = sl;
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}
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if (sl->preheight) {
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while (nh < sl->preheight && get_b_rand()) {
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nh++;
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}
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}
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else {
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while (nh <= sl->height && get_b_rand()) {
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nh++;
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}
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}
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/* Now we have the new height at which we wish to insert our new node */
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/*
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* Let us make sure that our tree is a least that tall (grow if
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* necessary)
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*/
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for (; sl->height < nh; sl->height++) {
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sl->top->up =
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(apr_skiplistnode *)apr_skiplist_alloc(sl, sizeof(apr_skiplistnode));
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sl->top->up->down = sl->top;
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sl->top = sl->topend = sl->top->up;
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#if 0
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sl->top->prev = sl->top->next = sl->top->nextindex =
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sl->top->previndex = sl->top->up = NULL;
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sl->top->data = NULL;
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#endif
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sl->top->sl = sl;
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}
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ch = sl->height;
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/* Find the node (or node after which we would insert) */
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/* Keep a stack to pop back through for insertion */
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/* malloc() is OK since we free the temp stack */
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m = sl->top;
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stack = (apr_skiplistnode **)malloc(sizeof(apr_skiplistnode *) * (nh));
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stacki = 0;
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while (m) {
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int compared = -1;
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if (m->next) {
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compared = comp(data, m->next->data);
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}
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if (compared == 0) {
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free(stack); /* OK. was malloc'ed */
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return 0;
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}
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if ((m->next == NULL) || (compared < 0)) {
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if (ch <= nh) {
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/* push on stack */
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stack[stacki++] = m;
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}
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m = m->down;
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ch--;
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}
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else {
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m = m->next;
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}
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}
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/* Pop the stack and insert nodes */
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p = NULL;
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for (; stacki > 0; stacki--) {
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m = stack[stacki - 1];
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tmp = (apr_skiplistnode *)apr_skiplist_alloc(sl, sizeof(apr_skiplistnode));
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tmp->next = m->next;
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if (m->next) {
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m->next->prev = tmp;
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}
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tmp->prev = m;
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tmp->up = NULL;
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tmp->nextindex = tmp->previndex = NULL;
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tmp->down = p;
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if (p) {
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p->up = tmp;
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}
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tmp->data = data;
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tmp->sl = sl;
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m->next = tmp;
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/* This sets ret to the bottom-most node we are inserting */
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if (!p) {
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ret = tmp;
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sl->size++; /* this seems to go here got each element to be counted */
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}
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p = tmp;
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}
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free(stack); /* OK. was malloc'ed */
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if (sl->index != NULL) {
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/*
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* this is a external insertion, we must insert into each index as
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* well
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*/
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apr_skiplistnode *ni, *li;
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li = ret;
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for (p = apr_skiplist_getlist(sl->index); p; apr_skiplist_next(sl->index, &p)) {
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ni = apr_skiplist_insert((apr_skiplist *) p->data, ret->data);
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li->nextindex = ni;
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ni->previndex = li;
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li = ni;
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}
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}
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else {
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/* sl->size++; */
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}
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sl->size++;
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return ret;
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}
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APR_DECLARE(int) apr_skiplist_remove(apr_skiplist *sl, void *data, apr_skiplist_freefunc myfree)
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{
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if (!sl->compare) {
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return 0;
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}
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return apr_skiplist_remove_compare(sl, data, myfree, sl->comparek);
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}
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#if 0
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void skiplist_print_struct(apr_skiplist * sl, char *prefix)
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{
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apr_skiplistnode *p, *q;
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fprintf(stderr, "Skiplist Structure (height: %d)\n", sl->height);
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p = sl->bottom;
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while (p) {
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q = p;
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fprintf(stderr, prefix);
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while (q) {
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fprintf(stderr, "%p ", q->data);
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q = q->up;
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}
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fprintf(stderr, "\n");
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p = p->next;
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}
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}
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#endif
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static int skiplisti_remove(apr_skiplist *sl, apr_skiplistnode *m, apr_skiplist_freefunc myfree)
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{
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apr_skiplistnode *p;
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if (!m) {
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return 0;
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}
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if (m->nextindex) {
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skiplisti_remove(m->nextindex->sl, m->nextindex, NULL);
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}
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while (m->up) {
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m = m->up;
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}
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while (m) {
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p = m;
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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);
|
|
}
|
|
apr_skiplist_free(sl, p);
|
|
}
|
|
sl->size--;
|
|
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 */
|
|
}
|
|
apr_skiplist_free(sl, p);
|
|
sl->height--;
|
|
}
|
|
if (!sl->top) {
|
|
sl->bottom = NULL;
|
|
}
|
|
return sl->height; /* return 1; ?? */
|
|
}
|
|
|
|
APR_DECLARE(int) apr_skiplist_remove_compare(apr_skiplist *sli,
|
|
void *data,
|
|
apr_skiplist_freefunc myfree, apr_skiplist_compare comp)
|
|
{
|
|
apr_skiplistnode *m;
|
|
apr_skiplist *sl;
|
|
if (comp == sli->comparek || !sli->index) {
|
|
sl = sli;
|
|
}
|
|
else {
|
|
apr_skiplist_find(sli->index, (void *)comp, &m);
|
|
sl = (apr_skiplist *) m->data;
|
|
}
|
|
skiplisti_find_compare(sl, data, &m, comp);
|
|
if (!m) {
|
|
return 0;
|
|
}
|
|
while (m->previndex) {
|
|
m = m->previndex;
|
|
}
|
|
return skiplisti_remove(sl, m, myfree);
|
|
}
|
|
|
|
APR_DECLARE(void) apr_skiplist_remove_all(apr_skiplist *sl, apr_skiplist_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
|
|
*/
|
|
apr_skiplistnode *m, *p, *u;
|
|
m = sl->bottom;
|
|
while (m) {
|
|
p = m->next;
|
|
if (p && myfree && p->data)
|
|
myfree(p->data);
|
|
while (m) {
|
|
u = m->up;
|
|
apr_skiplist_free(sl, p);
|
|
m = u;
|
|
}
|
|
m = p;
|
|
}
|
|
sl->top = sl->bottom = NULL;
|
|
sl->height = 0;
|
|
sl->size = 0;
|
|
}
|
|
|
|
APR_DECLARE(void *) apr_skiplist_pop(apr_skiplist *a, apr_skiplist_freefunc myfree)
|
|
{
|
|
apr_skiplistnode *sln;
|
|
void *data = NULL;
|
|
sln = apr_skiplist_getlist(a);
|
|
if (sln) {
|
|
data = sln->data;
|
|
skiplisti_remove(a, sln, myfree);
|
|
}
|
|
return data;
|
|
}
|
|
|
|
APR_DECLARE(void *) apr_skiplist_peek(apr_skiplist *a)
|
|
{
|
|
apr_skiplistnode *sln;
|
|
sln = apr_skiplist_getlist(a);
|
|
if (sln) {
|
|
return sln->data;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void skiplisti_destroy(void *vsl)
|
|
{
|
|
apr_skiplist_destroy((apr_skiplist *) vsl, NULL);
|
|
apr_skiplist_free((apr_skiplist *) vsl, vsl);
|
|
}
|
|
|
|
APR_DECLARE(void) apr_skiplist_destroy(apr_skiplist *sl, apr_skiplist_freefunc myfree)
|
|
{
|
|
while (apr_skiplist_pop(sl->index, skiplisti_destroy) != NULL)
|
|
;
|
|
apr_skiplist_remove_all(sl, myfree);
|
|
}
|
|
|
|
APR_DECLARE(apr_skiplist *) apr_skiplist_merge(apr_skiplist *sl1, apr_skiplist *sl2)
|
|
{
|
|
/* Check integrity! */
|
|
apr_skiplist temp;
|
|
struct apr_skiplistnode *b2;
|
|
if (sl1->bottomend == NULL || sl1->bottomend->prev == NULL) {
|
|
apr_skiplist_remove_all(sl1, NULL);
|
|
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) {
|
|
apr_skiplist_remove_all(sl2, NULL);
|
|
return sl1;
|
|
}
|
|
/* This is what makes it brute force... Just insert :/ */
|
|
b2 = apr_skiplist_getlist(sl2);
|
|
while (b2) {
|
|
apr_skiplist_insert(sl1, b2->data);
|
|
apr_skiplist_next(sl2, &b2);
|
|
}
|
|
apr_skiplist_remove_all(sl2, NULL);
|
|
return sl1;
|
|
}
|