src/cx/hash_map.h

Mon, 18 Dec 2023 14:14:47 +0100

author
Mike Becker <universe@uap-core.de>
date
Mon, 18 Dec 2023 14:14:47 +0100
changeset 759
475335643af4
parent 738
54b1d577551b
permissions
-rw-r--r--

increase version number to 3.1

remove per-file version information
from Doxygen output

universe@549 1 /*
universe@549 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@549 3 *
universe@549 4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
universe@549 5 *
universe@549 6 * Redistribution and use in source and binary forms, with or without
universe@549 7 * modification, are permitted provided that the following conditions are met:
universe@549 8 *
universe@549 9 * 1. Redistributions of source code must retain the above copyright
universe@549 10 * notice, this list of conditions and the following disclaimer.
universe@549 11 *
universe@549 12 * 2. Redistributions in binary form must reproduce the above copyright
universe@549 13 * notice, this list of conditions and the following disclaimer in the
universe@549 14 * documentation and/or other materials provided with the distribution.
universe@549 15 *
universe@549 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@549 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@549 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@549 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@549 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@549 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@549 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@549 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@549 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@549 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@549 26 * POSSIBILITY OF SUCH DAMAGE.
universe@549 27 */
universe@549 28 /**
universe@563 29 * \file hash_map.h
universe@563 30 * \brief Hash map implementation.
universe@549 31 * \author Mike Becker
universe@549 32 * \author Olaf Wintermann
universe@549 33 * \copyright 2-Clause BSD License
universe@549 34 */
universe@549 35
universe@549 36 #ifndef UCX_HASH_MAP_H
universe@549 37 #define UCX_HASH_MAP_H
universe@549 38
universe@549 39 #include "map.h"
universe@549 40
universe@549 41 #ifdef __cplusplus
universe@549 42 extern "C" {
universe@549 43 #endif
universe@549 44
universe@549 45 /** Internal structure for an element of a hash map. */
universe@658 46 struct cx_hash_map_element_s;
universe@549 47
universe@550 48 /**
universe@550 49 * Internal structure for a hash map.
universe@550 50 */
universe@550 51 struct cx_hash_map_s {
universe@550 52 /**
universe@550 53 * Base structure for maps.
universe@550 54 */
universe@550 55 struct cx_map_s base;
universe@550 56 /**
universe@550 57 * The buckets of this map, each containing a linked list of elements.
universe@550 58 */
universe@550 59 struct cx_hash_map_element_s **buckets;
universe@550 60 /**
universe@550 61 * The number of buckets.
universe@550 62 */
universe@550 63 size_t bucket_count;
universe@550 64 };
universe@550 65
universe@549 66
universe@549 67 /**
universe@550 68 * Creates a new hash map with the specified number of buckets.
universe@550 69 *
universe@550 70 * If \p buckets is zero, an implementation defined default will be used.
universe@550 71 *
universe@677 72 * If \p item_size is CX_STORE_POINTERS, the created map will be created as if
universe@669 73 * cxMapStorePointers() was called immediately after creation.
universe@669 74 *
universe@559 75 * @note Iterators provided by this hash map implementation provide the remove operation.
universe@738 76 * The index value of an iterator is incremented when the iterator advanced without removal.
universe@559 77 * In other words, when the iterator is finished, \c index==size .
universe@549 78 *
universe@549 79 * @param allocator the allocator to use
universe@658 80 * @param itemsize the size of one element
universe@549 81 * @param buckets the initial number of buckets in this hash map
universe@549 82 * @return a pointer to the new hash map
universe@549 83 */
universe@550 84 __attribute__((__nonnull__, __warn_unused_result__))
universe@549 85 CxMap *cxHashMapCreate(
universe@691 86 CxAllocator const *allocator,
universe@658 87 size_t itemsize,
universe@549 88 size_t buckets
universe@549 89 );
universe@549 90
universe@549 91 /**
universe@696 92 * Creates a new hash map with a default number of buckets.
universe@696 93 *
universe@696 94 * If \p item_size is CX_STORE_POINTERS, the created map will be created as if
universe@696 95 * cxMapStorePointers() was called immediately after creation.
universe@696 96 *
universe@696 97 * @note Iterators provided by this hash map implementation provide the remove operation.
universe@738 98 * The index value of an iterator is incremented when the iterator advanced without removal.
universe@696 99 * In other words, when the iterator is finished, \c index==size .
universe@696 100 *
universe@696 101 * @param itemsize the size of one element
universe@696 102 * @return a pointer to the new hash map
universe@696 103 */
universe@696 104 #define cxHashMapCreateSimple(itemsize) \
universe@696 105 cxHashMapCreate(cxDefaultAllocator, itemsize, 0)
universe@696 106
universe@696 107 /**
universe@549 108 * Increases the number of buckets, if necessary.
universe@549 109 *
universe@562 110 * The load threshold is \c 0.75*buckets. If the element count exceeds the load
universe@562 111 * threshold, the map will be rehashed. Otherwise, no action is performed and
universe@549 112 * this function simply returns 0.
universe@549 113 *
universe@549 114 * The rehashing process ensures, that the number of buckets is at least
universe@562 115 * 2.5 times the element count. So there is enough room for additional
universe@549 116 * elements without the need of another soon rehashing.
universe@549 117 *
universe@562 118 * You can use this function after filling a map to increase access performance.
universe@549 119 *
universe@549 120 * @note If the specified map is not a hash map, the behavior is undefined.
universe@549 121 *
universe@549 122 * @param map the map to rehash
universe@549 123 * @return zero on success, non-zero if a memory allocation error occurred
universe@549 124 */
universe@549 125 __attribute__((__nonnull__))
universe@562 126 int cxMapRehash(CxMap *map);
universe@549 127
universe@549 128
universe@549 129 #ifdef __cplusplus
universe@549 130 } // extern "C"
universe@549 131 #endif
universe@549 132
universe@549 133 #endif // UCX_HASH_MAP_H

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