src/cx/hash_map.h

Fri, 07 Jul 2023 18:22:13 +0200

author
Mike Becker <universe@uap-core.de>
date
Fri, 07 Jul 2023 18:22:13 +0200
changeset 738
54b1d577551b
parent 696
1ba4ec2e7a89
child 759
475335643af4
permissions
-rw-r--r--

fix typos in hash_map.h

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 * \version 3.0
universe@549 34 * \copyright 2-Clause BSD License
universe@549 35 */
universe@549 36
universe@549 37 #ifndef UCX_HASH_MAP_H
universe@549 38 #define UCX_HASH_MAP_H
universe@549 39
universe@549 40 #include "map.h"
universe@549 41
universe@549 42 #ifdef __cplusplus
universe@549 43 extern "C" {
universe@549 44 #endif
universe@549 45
universe@549 46 /** Internal structure for an element of a hash map. */
universe@658 47 struct cx_hash_map_element_s;
universe@549 48
universe@550 49 /**
universe@550 50 * Internal structure for a hash map.
universe@550 51 */
universe@550 52 struct cx_hash_map_s {
universe@550 53 /**
universe@550 54 * Base structure for maps.
universe@550 55 */
universe@550 56 struct cx_map_s base;
universe@550 57 /**
universe@550 58 * The buckets of this map, each containing a linked list of elements.
universe@550 59 */
universe@550 60 struct cx_hash_map_element_s **buckets;
universe@550 61 /**
universe@550 62 * The number of buckets.
universe@550 63 */
universe@550 64 size_t bucket_count;
universe@550 65 };
universe@550 66
universe@549 67
universe@549 68 /**
universe@550 69 * Creates a new hash map with the specified number of buckets.
universe@550 70 *
universe@550 71 * If \p buckets is zero, an implementation defined default will be used.
universe@550 72 *
universe@677 73 * If \p item_size is CX_STORE_POINTERS, the created map will be created as if
universe@669 74 * cxMapStorePointers() was called immediately after creation.
universe@669 75 *
universe@559 76 * @note Iterators provided by this hash map implementation provide the remove operation.
universe@738 77 * The index value of an iterator is incremented when the iterator advanced without removal.
universe@559 78 * In other words, when the iterator is finished, \c index==size .
universe@549 79 *
universe@549 80 * @param allocator the allocator to use
universe@658 81 * @param itemsize the size of one element
universe@549 82 * @param buckets the initial number of buckets in this hash map
universe@549 83 * @return a pointer to the new hash map
universe@549 84 */
universe@550 85 __attribute__((__nonnull__, __warn_unused_result__))
universe@549 86 CxMap *cxHashMapCreate(
universe@691 87 CxAllocator const *allocator,
universe@658 88 size_t itemsize,
universe@549 89 size_t buckets
universe@549 90 );
universe@549 91
universe@549 92 /**
universe@696 93 * Creates a new hash map with a default number of buckets.
universe@696 94 *
universe@696 95 * If \p item_size is CX_STORE_POINTERS, the created map will be created as if
universe@696 96 * cxMapStorePointers() was called immediately after creation.
universe@696 97 *
universe@696 98 * @note Iterators provided by this hash map implementation provide the remove operation.
universe@738 99 * The index value of an iterator is incremented when the iterator advanced without removal.
universe@696 100 * In other words, when the iterator is finished, \c index==size .
universe@696 101 *
universe@696 102 * @param itemsize the size of one element
universe@696 103 * @return a pointer to the new hash map
universe@696 104 */
universe@696 105 #define cxHashMapCreateSimple(itemsize) \
universe@696 106 cxHashMapCreate(cxDefaultAllocator, itemsize, 0)
universe@696 107
universe@696 108 /**
universe@549 109 * Increases the number of buckets, if necessary.
universe@549 110 *
universe@562 111 * The load threshold is \c 0.75*buckets. If the element count exceeds the load
universe@562 112 * threshold, the map will be rehashed. Otherwise, no action is performed and
universe@549 113 * this function simply returns 0.
universe@549 114 *
universe@549 115 * The rehashing process ensures, that the number of buckets is at least
universe@562 116 * 2.5 times the element count. So there is enough room for additional
universe@549 117 * elements without the need of another soon rehashing.
universe@549 118 *
universe@562 119 * You can use this function after filling a map to increase access performance.
universe@549 120 *
universe@549 121 * @note If the specified map is not a hash map, the behavior is undefined.
universe@549 122 *
universe@549 123 * @param map the map to rehash
universe@549 124 * @return zero on success, non-zero if a memory allocation error occurred
universe@549 125 */
universe@549 126 __attribute__((__nonnull__))
universe@562 127 int cxMapRehash(CxMap *map);
universe@549 128
universe@549 129
universe@549 130 #ifdef __cplusplus
universe@549 131 } // extern "C"
universe@549 132 #endif
universe@549 133
universe@549 134 #endif // UCX_HASH_MAP_H

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