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-rw-r--r--contrib/apr/tables/apr_skiplist.c650
1 files changed, 650 insertions, 0 deletions
diff --git a/contrib/apr/tables/apr_skiplist.c b/contrib/apr/tables/apr_skiplist.c
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+/* 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;
+}
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