]> granicus.if.org Git - apache/commitdiff
skiplist: Add skiplist capability to httpd
authorGraham Leggett <minfrin@apache.org>
Sat, 14 Sep 2013 14:26:55 +0000 (14:26 +0000)
committerGraham Leggett <minfrin@apache.org>
Sat, 14 Sep 2013 14:26:55 +0000 (14:26 +0000)
2.4.x patch: http://people.apache.org/~jim/patches/httpd-2.4-skiplist.patch

Submitted by: jim
Reviewed by: druggeri, minfrin

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1523254 13f79535-47bb-0310-9956-ffa450edef68

CHANGES
LICENSE
STATUS
include/ap_skiplist.h [new file with mode: 0644]
server/Makefile.in
server/skiplist.c [new file with mode: 0644]

diff --git a/CHANGES b/CHANGES
index 7976908b314c5be141d9b9c20e4bb1b47dd6545b..31d11b29f3a88ce77884df91cb5b7b9cc9f33ea1 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,8 @@
 
 Changes with Apache 2.4.7
 
+  * skiplist: Add skiplist capability to httpd [Jim Jagielski]
+
   * Sync 2.4 and trunk
        - Avoid some memory allocation and work when TRACE1 is not activated
        - fix typo in include guard
diff --git a/LICENSE b/LICENSE
index c7aa5ffdc3caa36714e44b05c01baf6f656e511d..1c38a6350400b3c3d5be17d1caa39bd72bf509f8 100644 (file)
--- a/LICENSE
+++ b/LICENSE
@@ -544,4 +544,24 @@ CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+for the server/skiplist.c component:
+
+/* ======================================================================
+ * Copyright (c) 2000,2006 Theo Schlossnagle
+ * All rights reserved.
+ * The following code was written by Theo Schlossnagle for use in the
+ * Backhand project at The Center for Networking and Distributed Systems
+ * at The Johns Hopkins University.
+ *
+ * This is a skiplist implementation to be used for abstract structures
+ * and is release under the LGPL license version 2.1 or later.  A copy
+ * of this license can be found file LGPL.
+ *
+ * Alternatively, this file may be licensed under the new BSD license.
+ * A copy of this license can be found file BSD.
+ *
+ * ======================================================================
+ */
+
+
 ====================================================================
diff --git a/STATUS b/STATUS
index 2b969c0aeb15a7b37d5759ed8cbfc5646a62fb9c..0cb3742717c77abbf7d122b287b89f6d8390f755 100644 (file)
--- a/STATUS
+++ b/STATUS
@@ -164,12 +164,6 @@ PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
     2.4.x patch: trunk patch works
     +1: trawick, covener, humbedooh
 
-  * skiplist: Add skiplist capability to httpd
-    trunk "patch": http://svn.apache.org/repos/asf/httpd/httpd/trunk/include/ap_skiplist.h
-                   http://svn.apache.org/repos/asf/httpd/httpd/trunk/server/skiplist.c
-    2.4.x patch: http://people.apache.org/~jim/patches/httpd-2.4-skiplist.patch
-    +1: jim, druggeri, minfrin
-
 
 PATCHES PROPOSED TO BACKPORT FROM TRUNK:
   [ New proposals should be added at the end of the list ]
diff --git a/include/ap_skiplist.h b/include/ap_skiplist.h
new file mode 100644 (file)
index 0000000..18d1bda
--- /dev/null
@@ -0,0 +1,82 @@
+/* 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.
+ */
+
+#ifndef _AP_SKIPLIST_P_H
+#define _AP_SKIPLIST_P_H
+
+#include "apr.h"
+#include "apr_portable.h"
+#include "ap_config.h"
+#include "httpd.h"
+
+/* This is the function type that must be implemented per object type
+   that is used in a skiplist for comparisons to maintain order */
+typedef int (*ap_skiplist_compare) (void *, void *);
+typedef void (*ap_skiplist_freefunc) (void *);
+
+struct ap_skiplist;
+struct ap_skiplistnode;
+
+typedef struct ap_skiplistnode ap_skiplistnode;
+typedef struct ap_skiplist ap_skiplist;
+
+AP_DECLARE(void *) ap_skiplist_alloc(ap_skiplist *sl, size_t size);
+
+AP_DECLARE(void) ap_skiplist_free(ap_skiplist *sl, void *mem);
+
+AP_DECLARE(apr_status_t) ap_skiplist_init(ap_skiplist **sl, apr_pool_t *p);
+
+AP_DECLARE(void) ap_skiplist_set_compare(ap_skiplist *sl, ap_skiplist_compare,
+                             ap_skiplist_compare);
+
+AP_DECLARE(void) ap_skiplist_add_index(ap_skiplist *sl, ap_skiplist_compare,
+                        ap_skiplist_compare);
+
+AP_DECLARE(ap_skiplistnode *) ap_skiplist_getlist(ap_skiplist *sl);
+
+AP_DECLARE(void *) ap_skiplist_find_compare(ap_skiplist *sl,
+                               void *data,
+                               ap_skiplistnode **iter,
+                               ap_skiplist_compare func);
+
+AP_DECLARE(void *) ap_skiplist_find(ap_skiplist *sl, void *data, ap_skiplistnode **iter);
+
+AP_DECLARE(void *) ap_skiplist_next(ap_skiplist *sl, ap_skiplistnode **iter);
+
+AP_DECLARE(void *) ap_skiplist_previous(ap_skiplist *sl, ap_skiplistnode **iter);
+
+
+AP_DECLARE(ap_skiplistnode *) ap_skiplist_insert_compare(ap_skiplist *sl,
+                                          void *data, ap_skiplist_compare comp);
+
+AP_DECLARE(ap_skiplistnode *) ap_skiplist_insert(ap_skiplist* sl, void *data);
+
+AP_DECLARE(int) ap_skiplist_remove_compare(ap_skiplist *sl, void *data,
+                               ap_skiplist_freefunc myfree, ap_skiplist_compare comp);
+
+AP_DECLARE(int) ap_skiplist_remove(ap_skiplist *sl, void *data, ap_skiplist_freefunc myfree);
+
+AP_DECLARE(void) ap_skiplist_remove_all(ap_skiplist *sl, ap_skiplist_freefunc myfree);
+
+AP_DECLARE(void) ap_skiplist_destroy(ap_skiplist *sl, ap_skiplist_freefunc myfree);
+
+AP_DECLARE(void *) ap_skiplist_pop(ap_skiplist *a, ap_skiplist_freefunc myfree);
+
+AP_DECLARE(void *) ap_skiplist_peek(ap_skiplist *a);
+
+AP_DECLARE(ap_skiplist *) ap_skiplist_merge(ap_skiplist *sl1, ap_skiplist *sl2);
+
+#endif
index 190107594aa0792bfb641df51f946ac9414411ba..e1e052eb199a088c1b2b4115cdad91752663b4a4 100644 (file)
@@ -14,7 +14,8 @@ LTLIBRARY_SOURCES = \
        util_filter.c util_pcre.c util_regex.c exports.c \
        scoreboard.c error_bucket.c protocol.c core.c request.c provider.c \
        eoc_bucket.c eor_bucket.c core_filters.c \
-       util_expr_parse.c util_expr_scan.c util_expr_eval.c
+       util_expr_parse.c util_expr_scan.c util_expr_eval.c \
+        skiplist.c
 LTLIBRARY_DEPENDENCIES = test_char.h
 
 TARGETS = delete-exports $(LTLIBRARY_NAME) $(CORE_IMPLIB_FILE) export_vars.h httpd.exp
diff --git a/server/skiplist.c b/server/skiplist.c
new file mode 100644 (file)
index 0000000..a02085f
--- /dev/null
@@ -0,0 +1,659 @@
+/* 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 "ap_skiplist.h"
+
+struct ap_skiplist {
+    ap_skiplist_compare compare;
+    ap_skiplist_compare comparek;
+    int height;
+    int preheight;
+    int size;
+    ap_skiplistnode *top;
+    ap_skiplistnode *bottom;
+    /* These two are needed for appending */
+    ap_skiplistnode *topend;
+    ap_skiplistnode *bottomend;
+    ap_skiplist *index;
+    apr_array_header_t *memlist;
+    apr_pool_t *pool;
+};
+
+struct ap_skiplistnode {
+    void *data;
+    ap_skiplistnode *next;
+    ap_skiplistnode *prev;
+    ap_skiplistnode *down;
+    ap_skiplistnode *up;
+    ap_skiplistnode *previndex;
+    ap_skiplistnode *nextindex;
+    ap_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;
+
+AP_DECLARE(void *) ap_skiplist_alloc(ap_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 ap_calloc(1, size);
+    }
+}
+
+AP_DECLARE(void) ap_skiplist_free(ap_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(ap_skiplist **s, apr_pool_t *p)
+{
+    ap_skiplist *sl;
+    if (p) {
+        sl = apr_pcalloc(p, sizeof(ap_skiplist));
+        sl->memlist = apr_array_make(p, 20, sizeof(memlist_t));
+    }
+    else {
+        sl = ap_calloc(1, sizeof(ap_skiplist));
+    }
+#if 0
+    sl->compare = (ap_skiplist_compare) NULL;
+    sl->comparek = (ap_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 *) (((ap_skiplist *) a)->compare);
+    void *bc = (void *) (((ap_skiplist *) b)->compare);
+    AP_DEBUG_ASSERT(a);
+    AP_DEBUG_ASSERT(b);
+    return ((ac < bc) ? -1 : ((ac > bc) ? 1 : 0));
+}
+
+static int indexing_compk(void *ac, void *b)
+{
+    void *bc = (void *) (((ap_skiplist *) b)->compare);
+    AP_DEBUG_ASSERT(b);
+    return ((ac < bc) ? -1 : ((ac > bc) ? 1 : 0));
+}
+
+AP_DECLARE(apr_status_t) ap_skiplist_init(ap_skiplist **s, apr_pool_t *p)
+{
+    ap_skiplist *sl;
+    skiplisti_init(s, p);
+    sl = *s;
+    skiplisti_init(&(sl->index), p);
+    ap_skiplist_set_compare(sl->index, indexing_comp, indexing_compk);
+    return APR_SUCCESS;
+}
+
+AP_DECLARE(void) ap_skiplist_set_compare(ap_skiplist *sl,
+                          ap_skiplist_compare comp,
+                          ap_skiplist_compare compk)
+{
+    if (sl->compare && sl->comparek) {
+        ap_skiplist_add_index(sl, comp, compk);
+    }
+    else {
+        sl->compare = comp;
+        sl->comparek = compk;
+    }
+}
+
+AP_DECLARE(void) ap_skiplist_add_index(ap_skiplist *sl,
+                        ap_skiplist_compare comp,
+                        ap_skiplist_compare compk)
+{
+    ap_skiplistnode *m;
+    ap_skiplist *ni;
+    int icount = 0;
+    ap_skiplist_find(sl->index, (void *)comp, &m);
+    if (m) {
+        return;                 /* Index already there! */
+    }
+    skiplisti_init(&ni, sl->pool);
+    ap_skiplist_set_compare(ni, comp, compk);
+    /* Build the new index... This can be expensive! */
+    m = ap_skiplist_insert(sl->index, ni);
+    while (m->prev) {
+        m = m->prev;
+        icount++;
+    }
+    for (m = ap_skiplist_getlist(sl); m; ap_skiplist_next(sl, &m)) {
+        int j = icount - 1;
+        ap_skiplistnode *nsln;
+        nsln = ap_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;
+    }
+}
+
+AP_DECLARE(ap_skiplistnode *) ap_skiplist_getlist(ap_skiplist *sl)
+{
+    if (!sl->bottom) {
+        return NULL;
+    }
+    return sl->bottom->next;
+}
+
+AP_DECLARE(void *) ap_skiplist_find(ap_skiplist *sl, void *data, ap_skiplistnode **iter)
+{
+    void *ret;
+    ap_skiplistnode *aiter;
+    if (!sl->compare) {
+        return 0;
+    }
+    if (iter) {
+        ret = ap_skiplist_find_compare(sl, data, iter, sl->compare);
+    }
+    else {
+        ret = ap_skiplist_find_compare(sl, data, &aiter, sl->compare);
+    }
+    return ret;
+}
+
+static int skiplisti_find_compare(ap_skiplist *sl, void *data,
+                           ap_skiplistnode **ret,
+                           ap_skiplist_compare comp)
+{
+    ap_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;
+}
+
+AP_DECLARE(void *) ap_skiplist_find_compare(ap_skiplist *sli, void *data,
+                               ap_skiplistnode **iter,
+                               ap_skiplist_compare comp)
+{
+    ap_skiplistnode *m = NULL;
+    ap_skiplist *sl;
+    if (comp == sli->compare || !sli->index) {
+        sl = sli;
+    }
+    else {
+        ap_skiplist_find(sli->index, (void *)comp, &m);
+        AP_DEBUG_ASSERT(m);
+        sl = (ap_skiplist *) m->data;
+    }
+    skiplisti_find_compare(sl, data, iter, sl->comparek);
+    return (iter && *iter) ? ((*iter)->data) : NULL;
+}
+
+
+AP_DECLARE(void *) ap_skiplist_next(ap_skiplist *sl, ap_skiplistnode **iter)
+{
+    if (!*iter) {
+        return NULL;
+    }
+    *iter = (*iter)->next;
+    return (*iter) ? ((*iter)->data) : NULL;
+}
+
+AP_DECLARE(void *) ap_skiplist_previous(ap_skiplist *sl, ap_skiplistnode **iter)
+{
+    if (!*iter) {
+        return NULL;
+    }
+    *iter = (*iter)->prev;
+    return (*iter) ? ((*iter)->data) : NULL;
+}
+
+AP_DECLARE(ap_skiplistnode *) ap_skiplist_insert(ap_skiplist *sl, void *data)
+{
+    if (!sl->compare) {
+        return 0;
+    }
+    return ap_skiplist_insert_compare(sl, data, sl->compare);
+}
+
+AP_DECLARE(ap_skiplistnode *) ap_skiplist_insert_compare(ap_skiplist *sl, void *data,
+                                      ap_skiplist_compare comp)
+{
+    ap_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 =
+            (ap_skiplistnode *)ap_skiplist_alloc(sl, sizeof(ap_skiplistnode));
+        AP_DEBUG_ASSERT(sl->top);
+#if 0
+        sl->top->next = (ap_skiplistnode *)NULL;
+        sl->top->data = (ap_skiplistnode *)NULL;
+        sl->top->prev = (ap_skiplistnode *)NULL;
+        sl->top->up = (ap_skiplistnode *)NULL;
+        sl->top->down = (ap_skiplistnode *)NULL;
+        sl->top->nextindex = (ap_skiplistnode *)NULL;
+        sl->top->previndex = (ap_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 =
+            (ap_skiplistnode *)ap_skiplist_alloc(sl, sizeof(ap_skiplistnode));
+        AP_DEBUG_ASSERT(sl->top->up);
+        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 = (ap_skiplistnode **)ap_malloc(sizeof(ap_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 ap_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 = (ap_skiplistnode *)ap_skiplist_alloc(sl, sizeof(ap_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
+         */
+        ap_skiplistnode *ni, *li;
+        li = ret;
+        for (p = ap_skiplist_getlist(sl->index); p; ap_skiplist_next(sl->index, &p)) {
+            ni = ap_skiplist_insert((ap_skiplist *) p->data, ret->data);
+            AP_DEBUG_ASSERT(ni);
+            li->nextindex = ni;
+            ni->previndex = li;
+            li = ni;
+        }
+    }
+    else {
+        /* sl->size++; */
+    }
+    sl->size++;
+    return ret;
+}
+
+AP_DECLARE(int) ap_skiplist_remove(ap_skiplist *sl, void *data, ap_skiplist_freefunc myfree)
+{
+    if (!sl->compare) {
+        return 0;
+    }
+    return ap_skiplist_remove_compare(sl, data, myfree, sl->comparek);
+}
+
+#if 0
+void skiplist_print_struct(ap_skiplist * sl, char *prefix)
+{
+    ap_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(ap_skiplist *sl, ap_skiplistnode *m, ap_skiplist_freefunc myfree)
+{
+    ap_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);
+        }
+        ap_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 */
+        }
+        ap_skiplist_free(sl, p);
+        sl->height--;
+    }
+    if (!sl->top) {
+        sl->bottom = NULL;
+    }
+    AP_DEBUG_ASSERT(sl->height >= 0);
+    return sl->height;  /* return 1; ?? */
+}
+
+AP_DECLARE(int) ap_skiplist_remove_compare(ap_skiplist *sli,
+                            void *data,
+                            ap_skiplist_freefunc myfree, ap_skiplist_compare comp)
+{
+    ap_skiplistnode *m;
+    ap_skiplist *sl;
+    if (comp == sli->comparek || !sli->index) {
+        sl = sli;
+    }
+    else {
+        ap_skiplist_find(sli->index, (void *)comp, &m);
+        AP_DEBUG_ASSERT(m);
+        sl = (ap_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);
+}
+
+AP_DECLARE(void) ap_skiplist_remove_all(ap_skiplist *sl, ap_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
+     */
+    ap_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;
+            ap_skiplist_free(sl, p);
+            m = u;
+        }
+        m = p;
+    }
+    sl->top = sl->bottom = NULL;
+    sl->height = 0;
+    sl->size = 0;
+}
+
+AP_DECLARE(void *) ap_skiplist_pop(ap_skiplist *a, ap_skiplist_freefunc myfree)
+{
+    ap_skiplistnode *sln;
+    void *data = NULL;
+    sln = ap_skiplist_getlist(a);
+    if (sln) {
+        data = sln->data;
+        skiplisti_remove(a, sln, myfree);
+    }
+    return data;
+}
+
+AP_DECLARE(void *) ap_skiplist_peek(ap_skiplist *a)
+{
+    ap_skiplistnode *sln;
+    sln = ap_skiplist_getlist(a);
+    if (sln) {
+        return sln->data;
+    }
+    return NULL;
+}
+
+static void skiplisti_destroy(void *vsl)
+{
+    ap_skiplist_destroy((ap_skiplist *) vsl, NULL);
+    ap_skiplist_free((ap_skiplist *) vsl, vsl);
+}
+
+AP_DECLARE(void) ap_skiplist_destroy(ap_skiplist *sl, ap_skiplist_freefunc myfree)
+{
+    while (ap_skiplist_pop(sl->index, skiplisti_destroy) != NULL)
+        ;
+    ap_skiplist_remove_all(sl, myfree);
+}
+
+AP_DECLARE(ap_skiplist *) ap_skiplist_merge(ap_skiplist *sl1, ap_skiplist *sl2)
+{
+    /* Check integrity! */
+    ap_skiplist temp;
+    struct ap_skiplistnode *b2;
+    if (sl1->bottomend == NULL || sl1->bottomend->prev == NULL) {
+        ap_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) {
+        ap_skiplist_remove_all(sl2, NULL);
+        return sl1;
+    }
+    /* This is what makes it brute force... Just insert :/ */
+    b2 = ap_skiplist_getlist(sl2);
+    while (b2) {
+        ap_skiplist_insert(sl1, b2->data);
+        ap_skiplist_next(sl2, &b2);
+    }
+    ap_skiplist_remove_all(sl2, NULL);
+    return sl1;
+}