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