universe@549: /*
universe@549:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@549:  *
universe@549:  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
universe@549:  *
universe@549:  * Redistribution and use in source and binary forms, with or without
universe@549:  * modification, are permitted provided that the following conditions are met:
universe@549:  *
universe@549:  *   1. Redistributions of source code must retain the above copyright
universe@549:  *      notice, this list of conditions and the following disclaimer.
universe@549:  *
universe@549:  *   2. Redistributions in binary form must reproduce the above copyright
universe@549:  *      notice, this list of conditions and the following disclaimer in the
universe@549:  *      documentation and/or other materials provided with the distribution.
universe@549:  *
universe@549:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@549:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@549:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@549:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@549:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@549:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@549:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@549:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@549:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@549:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@549:  * POSSIBILITY OF SUCH DAMAGE.
universe@549:  */
universe@549: /**
universe@563:  * \file hash_map.h
universe@563:  * \brief Hash map implementation.
universe@549:  * \author Mike Becker
universe@549:  * \author Olaf Wintermann
universe@549:  * \copyright 2-Clause BSD License
universe@549:  */
universe@549: 
universe@549: #ifndef UCX_HASH_MAP_H
universe@549: #define UCX_HASH_MAP_H
universe@549: 
universe@549: #include "map.h"
universe@549: 
universe@549: #ifdef __cplusplus
universe@549: extern "C" {
universe@549: #endif
universe@549: 
universe@549: /** Internal structure for an element of a hash map. */
universe@658: struct cx_hash_map_element_s;
universe@549: 
universe@550: /**
universe@550:  * Internal structure for a hash map.
universe@550:  */
universe@550: struct cx_hash_map_s {
universe@550:     /**
universe@550:      * Base structure for maps.
universe@550:      */
universe@550:     struct cx_map_s base;
universe@550:     /**
universe@550:      * The buckets of this map, each containing a linked list of elements.
universe@550:      */
universe@550:     struct cx_hash_map_element_s **buckets;
universe@550:     /**
universe@550:      * The number of buckets.
universe@550:      */
universe@550:     size_t bucket_count;
universe@550: };
universe@550: 
universe@549: 
universe@549: /**
universe@550:  * Creates a new hash map with the specified number of buckets.
universe@550:  *
universe@550:  * If \p buckets is zero, an implementation defined default will be used.
universe@550:  *
universe@677:  * If \p item_size is CX_STORE_POINTERS, the created map will be created as if
universe@669:  * cxMapStorePointers() was called immediately after creation.
universe@669:  *
universe@559:  * @note Iterators provided by this hash map implementation provide the remove operation.
universe@738:  * The index value of an iterator is incremented when the iterator advanced without removal.
universe@559:  * In other words, when the iterator is finished, \c index==size .
universe@549:  *
universe@549:  * @param allocator the allocator to use
universe@658:  * @param itemsize the size of one element
universe@549:  * @param buckets the initial number of buckets in this hash map
universe@549:  * @return a pointer to the new hash map
universe@549:  */
universe@550: __attribute__((__nonnull__, __warn_unused_result__))
universe@549: CxMap *cxHashMapCreate(
universe@691:         CxAllocator const *allocator,
universe@658:         size_t itemsize,
universe@549:         size_t buckets
universe@549: );
universe@549: 
universe@549: /**
universe@696:  * Creates a new hash map with a default number of buckets.
universe@696:  *
universe@696:  * If \p item_size is CX_STORE_POINTERS, the created map will be created as if
universe@696:  * cxMapStorePointers() was called immediately after creation.
universe@696:  *
universe@696:  * @note Iterators provided by this hash map implementation provide the remove operation.
universe@738:  * The index value of an iterator is incremented when the iterator advanced without removal.
universe@696:  * In other words, when the iterator is finished, \c index==size .
universe@696:  *
universe@696:  * @param itemsize the size of one element
universe@696:  * @return a pointer to the new hash map
universe@696:  */
universe@696: #define cxHashMapCreateSimple(itemsize) \
universe@696:     cxHashMapCreate(cxDefaultAllocator, itemsize, 0)
universe@696: 
universe@696: /**
universe@549:  * Increases the number of buckets, if necessary.
universe@549:  *
universe@562:  * The load threshold is \c 0.75*buckets. If the element count exceeds the load
universe@562:  * threshold, the map will be rehashed. Otherwise, no action is performed and
universe@549:  * this function simply returns 0.
universe@549:  *
universe@549:  * The rehashing process ensures, that the number of buckets is at least
universe@562:  * 2.5 times the element count. So there is enough room for additional
universe@549:  * elements without the need of another soon rehashing.
universe@549:  *
universe@562:  * You can use this function after filling a map to increase access performance.
universe@549:  *
universe@549:  * @note If the specified map is not a hash map, the behavior is undefined.
universe@549:  *
universe@549:  * @param map the map to rehash
universe@549:  * @return zero on success, non-zero if a memory allocation error occurred
universe@549:  */
universe@549: __attribute__((__nonnull__))
universe@562: int cxMapRehash(CxMap *map);
universe@549: 
universe@549: 
universe@549: #ifdef __cplusplus
universe@549: } // extern "C"
universe@549: #endif
universe@549: 
universe@549: #endif // UCX_HASH_MAP_H