Adding upstream version 1.7.2.upstream/1.7.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 381 insertions, 0 deletions

diff --git a/include/apr_skiplist.h b/include/apr_skiplist.h
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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.
+ */
+
+#ifndef APR_SKIPLIST_H
+#define APR_SKIPLIST_H
+/**
+ * @file apr_skiplist.h
+ * @brief APR skip list implementation
+ */
+
+#include "apr.h"
+#include "apr_portable.h"
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/**
+ * @defgroup apr_skiplist Skip list implementation
+ * Refer to http://en.wikipedia.org/wiki/Skip_list for information
+ * about the purpose of and ideas behind skip lists.
+ * @ingroup APR
+ * @{
+ */
+
+/**
+ * apr_skiplist_compare is the function type that must be implemented 
+ * per object type that is used in a skip list for comparisons to maintain
+ * order
+ * */
+typedef int (*apr_skiplist_compare) (void *, void *);
+
+/**
+ * apr_skiplist_freefunc is the function type that must be implemented
+ * to handle elements as they are removed from a skip list.
+ */
+typedef void (*apr_skiplist_freefunc) (void *);
+
+/** Opaque structure used to represent the skip list */
+struct apr_skiplist;
+/** Opaque structure used to represent the skip list */
+typedef struct apr_skiplist apr_skiplist;
+
+/** 
+ * Opaque structure used to represent abstract nodes in the skip list
+ * (an abstraction above the raw elements which are collected in the
+ * skip list).
+ */
+struct apr_skiplistnode;
+/** Opaque structure */
+typedef struct apr_skiplistnode apr_skiplistnode;
+
+/**
+ * Allocate memory using the same mechanism as the skip list.
+ * @param sl The skip list
+ * @param size The amount to allocate
+ * @remark If a pool was provided to apr_skiplist_init(), memory will
+ * be allocated from the pool or from a free list maintained with
+ * the skip list.  Otherwise, memory will be allocated using the
+ * C standard library heap functions.
+ */
+APR_DECLARE(void *) apr_skiplist_alloc(apr_skiplist *sl, size_t size);
+
+/**
+ * Free memory using the same mechanism as the skip list.
+ * @param sl The skip list
+ * @param mem The object to free
+ * @remark If a pool was provided to apr_skiplist_init(), memory will
+ * be added to a free list maintained with the skip list and be available
+ * to operations on the skip list or to other calls to apr_skiplist_alloc().
+ * Otherwise, memory will be freed using the  C standard library heap
+ * functions.
+ */
+APR_DECLARE(void) apr_skiplist_free(apr_skiplist *sl, void *mem);
+
+/**
+ * Allocate a new skip list
+ * @param sl The pointer in which to return the newly created skip list
+ * @param p The pool from which to allocate the skip list (optional).
+ * @remark Unlike most APR functions, a pool is optional.  If no pool
+ * is provided, the C standard library heap functions will be used instead.
+ */
+APR_DECLARE(apr_status_t) apr_skiplist_init(apr_skiplist **sl, apr_pool_t *p);
+
+/**
+ * Set the comparison functions to be used for searching the skip list.
+ * @param sl The skip list
+ * @param XXX1 FIXME
+ * @param XXX2 FIXME
+ *
+ * @remark If existing comparison functions are being replaced, the index
+ * will be replaced during this call.  That is a potentially expensive
+ * operation.
+ */
+APR_DECLARE(void) apr_skiplist_set_compare(apr_skiplist *sl, apr_skiplist_compare XXX1,
+                             apr_skiplist_compare XXX2);
+
+/**
+ * Set the indexing functions to the specified comparison functions and
+ * rebuild the index.
+ * @param sl The skip list
+ * @param XXX1 FIXME
+ * @param XXX2 FIXME
+ *
+ * @remark If an index already exists, it will not be replaced and the
+ * comparison functions will not be changed.
+ */
+APR_DECLARE(void) apr_skiplist_add_index(apr_skiplist *sl, apr_skiplist_compare XXX1,
+                        apr_skiplist_compare XXX2);
+
+/**
+ * Return the list maintained by the skip list abstraction.
+ * @param sl The skip list
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_getlist(apr_skiplist *sl);
+
+/**
+ * Return the next matching element in the skip list using the specified
+ * comparison function.
+ * @param sl The skip list
+ * @param data The value to search for
+ * @param iter A pointer to the returned skip list node representing the element
+ * found
+ * @param func The comparison function to use
+ */
+APR_DECLARE(void *) apr_skiplist_find_compare(apr_skiplist *sl,
+                               void *data,
+                               apr_skiplistnode **iter,
+                               apr_skiplist_compare func);
+
+/**
+ * Return the next matching element in the skip list using the current comparison
+ * function.
+ * @param sl The skip list
+ * @param data The value to search for
+ * @param iter A pointer to the returned skip list node representing the element
+ * found
+ */
+APR_DECLARE(void *) apr_skiplist_find(apr_skiplist *sl, void *data, apr_skiplistnode **iter);
+
+/**
+ * Return the last matching element in the skip list using the specified
+ * comparison function.
+ * @param sl The skip list
+ * @param data The value to search for
+ * @param iter A pointer to the returned skip list node representing the element
+ * found
+ * @param comp The comparison function to use
+ */
+APR_DECLARE(void *) apr_skiplist_last_compare(apr_skiplist *sl, void *data,
+                                              apr_skiplistnode **iter,
+                                              apr_skiplist_compare comp);
+
+/**
+ * Return the last matching element in the skip list using the current comparison
+ * function.
+ * @param sl The skip list
+ * @param data The value to search for
+ * @param iter A pointer to the returned skip list node representing the element
+ * found
+ */
+APR_DECLARE(void *) apr_skiplist_last(apr_skiplist *sl, void *data,
+                                      apr_skiplistnode **iter);
+
+/**
+ * Return the next element in the skip list.
+ * @param sl The skip list
+ * @param iter On entry, a pointer to the skip list node to start with; on return,
+ * a pointer to the skip list node representing the element returned
+ * @remark If iter points to a NULL value on entry, NULL will be returned.
+ */
+APR_DECLARE(void *) apr_skiplist_next(apr_skiplist *sl, apr_skiplistnode **iter);
+
+/**
+ * Return the previous element in the skip list.
+ * @param sl The skip list
+ * @param iter On entry, a pointer to the skip list node to start with; on return,
+ * a pointer to the skip list node representing the element returned
+ * @remark If iter points to a NULL value on entry, NULL will be returned.
+ */
+APR_DECLARE(void *) apr_skiplist_previous(apr_skiplist *sl, apr_skiplistnode **iter);
+
+/**
+ * Return the element of the skip list node
+ * @param iter The skip list node
+ */
+APR_DECLARE(void *) apr_skiplist_element(apr_skiplistnode *iter);
+
+/**
+ * Insert an element into the skip list using the specified comparison function
+ * if it does not already exist.
+ * @param sl The skip list
+ * @param data The element to insert
+ * @param comp The comparison function to use for placement into the skip list
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_insert_compare(apr_skiplist *sl,
+                                          void *data, apr_skiplist_compare comp);
+
+/**
+ * Insert an element into the skip list using the existing comparison function
+ * if it does not already exist.
+ * @param sl The skip list
+ * @param data The element to insert
+ * @remark If no comparison function has been set for the skip list, the element
+ * will not be inserted and NULL will be returned.
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_insert(apr_skiplist* sl, void *data);
+
+/**
+ * Add an element into the skip list using the specified comparison function
+ * allowing for duplicates.
+ * @param sl The skip list
+ * @param data The element to add
+ * @param comp The comparison function to use for placement into the skip list
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_add_compare(apr_skiplist *sl,
+                                          void *data, apr_skiplist_compare comp);
+
+/**
+ * Add an element into the skip list using the existing comparison function
+ * allowing for duplicates.
+ * @param sl The skip list
+ * @param data The element to insert
+ * @remark If no comparison function has been set for the skip list, the element
+ * will not be inserted and NULL will be returned.
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_add(apr_skiplist* sl, void *data);
+
+/**
+ * Add an element into the skip list using the specified comparison function
+ * removing the existing duplicates.
+ * @param sl The skip list
+ * @param data The element to insert
+ * @param comp The comparison function to use for placement into the skip list
+ * @param myfree A function to be called for each removed duplicate
+ * @remark If no comparison function has been set for the skip list, the element
+ * will not be inserted, none will be replaced, and NULL will be returned.
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_replace_compare(apr_skiplist *sl,
+                                    void *data, apr_skiplist_freefunc myfree,
+                                    apr_skiplist_compare comp);
+
+/**
+ * Add an element into the skip list using the existing comparison function
+ * removing the existing duplicates.
+ * @param sl The skip list
+ * @param data The element to insert
+ * @param myfree A function to be called for each removed duplicate
+ * @remark If no comparison function has been set for the skip list, the element
+ * will not be inserted, none will be replaced, and NULL will be returned.
+ */
+APR_DECLARE(apr_skiplistnode *) apr_skiplist_replace(apr_skiplist *sl,
+                                    void *data, apr_skiplist_freefunc myfree);
+
+/**
+ * Remove a node from the skip list.
+ * @param sl The skip list
+ * @param iter The skip list node to remove
+ * @param myfree A function to be called for the removed element
+ */
+APR_DECLARE(int) apr_skiplist_remove_node(apr_skiplist *sl,
+                                          apr_skiplistnode *iter,
+                                          apr_skiplist_freefunc myfree);
+
+/**
+ * Remove an element from the skip list using the specified comparison function for
+ * locating the element. In the case of duplicates, the 1st entry will be removed.
+ * @param sl The skip list
+ * @param data The element to remove
+ * @param myfree A function to be called for each removed element
+ * @param comp The comparison function to use for placement into the skip list
+ * @remark If the element is not found, 0 will be returned.  Otherwise, the heightXXX
+ * will be returned.
+ */
+APR_DECLARE(int) apr_skiplist_remove_compare(apr_skiplist *sl, void *data,
+                               apr_skiplist_freefunc myfree, apr_skiplist_compare comp);
+
+/**
+ * Remove an element from the skip list using the existing comparison function for
+ * locating the element. In the case of duplicates, the 1st entry will be removed.
+ * @param sl The skip list
+ * @param data The element to remove
+ * @param myfree A function to be called for each removed element
+ * @remark If the element is not found, 0 will be returned.  Otherwise, the heightXXX
+ * will be returned.
+ * @remark If no comparison function has been set for the skip list, the element
+ * will not be removed and 0 will be returned.
+ */
+APR_DECLARE(int) apr_skiplist_remove(apr_skiplist *sl, void *data, apr_skiplist_freefunc myfree);
+
+/**
+ * Remove all elements from the skip list.
+ * @param sl The skip list
+ * @param myfree A function to be called for each removed element
+ */
+APR_DECLARE(void) apr_skiplist_remove_all(apr_skiplist *sl, apr_skiplist_freefunc myfree);
+
+/**
+ * Remove each element from the skip list.
+ * @param sl The skip list
+ * @param myfree A function to be called for each removed element
+ */
+APR_DECLARE(void) apr_skiplist_destroy(apr_skiplist *sl, apr_skiplist_freefunc myfree);
+
+/**
+ * Return the first element in the skip list, removing the element from the skip list.
+ * @param sl The skip list
+ * @param myfree A function to be called for the removed element
+ * @remark NULL will be returned if there are no elements
+ */
+APR_DECLARE(void *) apr_skiplist_pop(apr_skiplist *sl, apr_skiplist_freefunc myfree);
+
+/**
+ * Return the first element in the skip list, leaving the element in the skip list.
+ * @param sl The skip list
+ * @remark NULL will be returned if there are no elements
+ */
+APR_DECLARE(void *) apr_skiplist_peek(apr_skiplist *sl);
+
+/**
+ * Return the size of the list (number of elements), in O(1).
+ * @param sl The skip list
+ */
+APR_DECLARE(size_t) apr_skiplist_size(const apr_skiplist *sl);
+
+/**
+ * Return the height of the list (number of skip paths), in O(1).
+ * @param sl The skip list
+ */
+APR_DECLARE(int) apr_skiplist_height(const apr_skiplist *sl);
+
+/**
+ * Return the predefined maximum height of the skip list.
+ * @param sl The skip list
+ */
+APR_DECLARE(int) apr_skiplist_preheight(const apr_skiplist *sl);
+
+/**
+ * Set a predefined maximum height for the skip list.
+ * @param sl The skip list
+ * @param to The preheight to set, or a nul/negative value to disable.
+ * @remark When a preheight is used, the height of each inserted element is
+ * computed randomly up to this preheight instead of the current skip list's
+ * height plus one used by the default implementation. Using a preheight can
+ * probably ensure more fairness with long living elements (since with an
+ * adaptative height, former elements may have been created with a low height,
+ * hence a longest path to reach them while the skip list grows). On the other
+ * hand, the default behaviour (preheight <= 0) with a growing and decreasing
+ * maximum height is more adaptative/suitable for short living values.
+ * @note Should be called before any insertion/add.
+ */
+APR_DECLARE(void) apr_skiplist_set_preheight(apr_skiplist *sl, int to);
+
+/**
+ * Merge two skip lists.  XXX SEMANTICS
+ * @param sl1 One of two skip lists to be merged
+ * @param sl2 The other of two skip lists to be merged
+ */
+APR_DECLARE(apr_skiplist *) apr_skiplist_merge(apr_skiplist *sl1, apr_skiplist *sl2);
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ! APR_SKIPLIST_H */