src/cx/iterator.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 740
378578666c83
child 829
7d4e31d295af
permissions
-rw-r--r--

increase version number to 3.1

remove per-file version information
from Doxygen output

universe@494 1 /*
universe@494 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@494 3 *
universe@494 4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
universe@494 5 *
universe@494 6 * Redistribution and use in source and binary forms, with or without
universe@494 7 * modification, are permitted provided that the following conditions are met:
universe@494 8 *
universe@494 9 * 1. Redistributions of source code must retain the above copyright
universe@494 10 * notice, this list of conditions and the following disclaimer.
universe@494 11 *
universe@494 12 * 2. Redistributions in binary form must reproduce the above copyright
universe@494 13 * notice, this list of conditions and the following disclaimer in the
universe@494 14 * documentation and/or other materials provided with the distribution.
universe@494 15 *
universe@494 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@494 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@494 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@494 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@494 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@494 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@494 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@494 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@494 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@494 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@494 26 * POSSIBILITY OF SUCH DAMAGE.
universe@494 27 */
universe@494 28 /**
universe@494 29 * \file iterator.h
universe@494 30 * \brief Interface for iterator implementations.
universe@494 31 * \author Mike Becker
universe@494 32 * \author Olaf Wintermann
universe@494 33 * \copyright 2-Clause BSD License
universe@494 34 */
universe@494 35
universe@494 36 #ifndef UCX_ITERATOR_H
universe@494 37 #define UCX_ITERATOR_H
universe@494 38
universe@494 39 #include "common.h"
universe@494 40
universe@494 41 /**
universe@630 42 * The base of mutating and non-mutating iterators.
universe@494 43 */
universe@630 44 struct cx_iterator_base_s {
universe@494 45 /**
universe@494 46 * True iff the iterator points to valid data.
universe@494 47 */
universe@551 48 __attribute__ ((__nonnull__))
universe@630 49 bool (*valid)(void const *);
universe@494 50
universe@494 51 /**
universe@494 52 * Returns a pointer to the current element.
universe@704 53 *
universe@704 54 * When valid returns false, the behavior of this function is undefined.
universe@494 55 */
universe@551 56 __attribute__ ((__nonnull__))
universe@630 57 void *(*current)(void const *);
universe@494 58
universe@494 59 /**
universe@641 60 * Original implementation in case the function needs to be wrapped.
universe@641 61 */
universe@641 62 __attribute__ ((__nonnull__))
universe@641 63 void *(*current_impl)(void const *);
universe@641 64
universe@641 65 /**
universe@494 66 * Advances the iterator.
universe@704 67 *
universe@704 68 * When valid returns false, the behavior of this function is undefined.
universe@494 69 */
universe@551 70 __attribute__ ((__nonnull__))
universe@630 71 void (*next)(void *);
universe@630 72
universe@630 73 /**
universe@630 74 * Flag current element for removal, if possible.
universe@704 75 *
universe@704 76 * When valid returns false, the behavior of this function is undefined.
universe@630 77 */
universe@630 78 __attribute__ ((__nonnull__))
universe@630 79 bool (*flag_removal)(void *);
universe@630 80
universe@630 81 /**
universe@695 82 * Indicates whether this iterator may remove elements.
universe@630 83 */
universe@630 84 bool mutating;
universe@630 85
universe@630 86 /**
universe@630 87 * Internal flag for removing the current element when advancing.
universe@630 88 */
universe@630 89 bool remove;
universe@630 90 };
universe@630 91
universe@630 92 /**
universe@630 93 * Internal iterator struct - use CxMutIterator.
universe@630 94 */
universe@630 95 struct cx_mut_iterator_s {
universe@630 96
universe@630 97 /**
universe@630 98 * The base properties of this iterator.
universe@630 99 */
universe@630 100 struct cx_iterator_base_s base;
universe@495 101
universe@495 102 /**
universe@495 103 * Handle for the current element, if required.
universe@495 104 */
universe@495 105 void *elem_handle;
universe@495 106
universe@495 107 /**
universe@495 108 * Handle for the source collection, if any.
universe@495 109 */
universe@495 110 void *src_handle;
universe@495 111
universe@495 112 /**
universe@551 113 * Field for storing a key-value pair.
universe@551 114 * May be used by iterators that iterate over k/v-collections.
universe@551 115 */
universe@551 116 struct {
universe@551 117 /**
universe@551 118 * A pointer to the key.
universe@551 119 */
universe@630 120 void const *key;
universe@551 121 /**
universe@551 122 * A pointer to the value.
universe@551 123 */
universe@551 124 void *value;
universe@551 125 } kv_data;
universe@551 126
universe@551 127 /**
universe@551 128 * Field for storing a slot number.
universe@551 129 * May be used by iterators that iterate over multi-bucket collections.
universe@551 130 */
universe@551 131 size_t slot;
universe@551 132
universe@551 133 /**
universe@495 134 * If the iterator is position-aware, contains the index of the element in the underlying collection.
universe@495 135 * Otherwise, this field is usually uninitialized.
universe@495 136 */
universe@495 137 size_t index;
universe@630 138 };
universe@630 139
universe@630 140 /**
universe@630 141 * Mutating iterator value type.
universe@630 142 *
universe@630 143 * An iterator points to a certain element in an (possibly unbounded) chain of elements.
universe@630 144 * Iterators that are based on collections (which have a defined "first" element), are supposed
universe@630 145 * to be "position-aware", which means that they keep track of the current index within the collection.
universe@630 146 *
universe@630 147 * @note Objects that are pointed to by an iterator are mutable through that iterator. However, if the
universe@630 148 * iterator is based on a collection and the underlying collection is mutated by other means than this iterator
universe@630 149 * (e.g. elements added or removed), the iterator becomes invalid (regardless of what cxIteratorValid() returns)
universe@630 150 * and MUST be re-obtained from the collection.
universe@630 151 *
universe@630 152 * @see CxIterator
universe@630 153 */
universe@630 154 typedef struct cx_mut_iterator_s CxMutIterator;
universe@630 155
universe@630 156 /**
universe@630 157 * Internal iterator struct - use CxIterator.
universe@630 158 */
universe@630 159 struct cx_iterator_s {
universe@495 160
universe@495 161 /**
universe@630 162 * The base properties of this iterator.
universe@495 163 */
universe@630 164 struct cx_iterator_base_s base;
universe@630 165
universe@630 166 /**
universe@630 167 * Handle for the current element, if required.
universe@630 168 */
universe@630 169 void *elem_handle;
universe@630 170
universe@630 171 /**
universe@630 172 * Handle for the source collection, if any.
universe@630 173 */
universe@630 174 void const *src_handle;
universe@630 175
universe@630 176 /**
universe@630 177 * Field for storing a key-value pair.
universe@630 178 * May be used by iterators that iterate over k/v-collections.
universe@630 179 */
universe@630 180 struct {
universe@630 181 /**
universe@630 182 * A pointer to the key.
universe@630 183 */
universe@630 184 void const *key;
universe@630 185 /**
universe@630 186 * A pointer to the value.
universe@630 187 */
universe@630 188 void *value;
universe@630 189 } kv_data;
universe@630 190
universe@630 191 /**
universe@630 192 * Field for storing a slot number.
universe@630 193 * May be used by iterators that iterate over multi-bucket collections.
universe@630 194 */
universe@630 195 size_t slot;
universe@630 196
universe@630 197 /**
universe@630 198 * If the iterator is position-aware, contains the index of the element in the underlying collection.
universe@630 199 * Otherwise, this field is usually uninitialized.
universe@630 200 */
universe@630 201 size_t index;
universe@494 202 };
universe@494 203
universe@494 204 /**
universe@500 205 * Iterator value type.
olaf@740 206 * An iterator points to a certain element in a (possibly unbounded) chain of elements.
universe@500 207 * Iterators that are based on collections (which have a defined "first" element), are supposed
universe@500 208 * to be "position-aware", which means that they keep track of the current index within the collection.
universe@500 209 *
universe@630 210 * @note Objects that are pointed to by an iterator are always mutable through that iterator. However,
universe@630 211 * this iterator cannot mutate the collection itself (add or remove elements) and any mutation of the
olaf@740 212 * collection by other means makes this iterator invalid (regardless of what cxIteratorValid() returns).
universe@630 213 *
universe@630 214 * @see CxMutIterator
universe@500 215 */
universe@500 216 typedef struct cx_iterator_s CxIterator;
universe@500 217
universe@500 218 /**
universe@494 219 * Checks if the iterator points to valid data.
universe@494 220 *
universe@494 221 * This is especially false for past-the-end iterators.
universe@494 222 *
universe@630 223 * @param iter the iterator
universe@494 224 * @return true iff the iterator points to valid data
universe@494 225 */
universe@630 226 #define cxIteratorValid(iter) (iter).base.valid(&(iter))
universe@494 227
universe@494 228 /**
universe@494 229 * Returns a pointer to the current element.
universe@494 230 *
universe@494 231 * The behavior is undefined if this iterator is invalid.
universe@494 232 *
universe@630 233 * @param iter the iterator
universe@494 234 * @return a pointer to the current element
universe@494 235 */
universe@630 236 #define cxIteratorCurrent(iter) (iter).base.current(&iter)
universe@494 237
universe@494 238 /**
universe@494 239 * Advances the iterator to the next element.
universe@494 240 *
universe@630 241 * @param iter the iterator
universe@494 242 */
universe@630 243 #define cxIteratorNext(iter) (iter).base.next(&iter)
universe@630 244
universe@630 245 /**
universe@630 246 * Flags the current element for removal.
universe@630 247 *
universe@630 248 * @param iter the iterator
universe@630 249 * @return false if this iterator cannot remove the element
universe@630 250 */
universe@630 251 #define cxIteratorFlagRemoval(iter) (iter).base.flag_removal(&iter)
universe@494 252
universe@496 253 /**
universe@496 254 * Loops over an iterator.
universe@496 255 * @param type the type of the elements
universe@496 256 * @param elem the name of the iteration variable
universe@496 257 * @param iter the iterator
universe@496 258 */
universe@496 259 #define cx_foreach(type, elem, iter) \
universe@630 260 for (type elem; cxIteratorValid(iter) && (elem = (type)cxIteratorCurrent(iter)) != NULL ; cxIteratorNext(iter))
universe@496 261
universe@628 262 #endif // UCX_ITERATOR_H

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