| 1 | /* Copyright (C) 2010-2020 The RetroArch team |
| 2 | * |
| 3 | * --------------------------------------------------------------------------------------- |
| 4 | * The following license statement only applies to this file (generic_queue.c). |
| 5 | * --------------------------------------------------------------------------------------- |
| 6 | * |
| 7 | * Permission is hereby granted, free of charge, |
| 8 | * to any person obtaining a copy of this software and associated documentation files (the "Software"), |
| 9 | * to deal in the Software without restriction, including without limitation the rights to |
| 10 | * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| 11 | * and to permit persons to whom the Software is furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. |
| 14 | * |
| 15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, |
| 16 | * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| 18 | * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
| 19 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 20 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 21 | */ |
| 22 | |
| 23 | #include <boolean.h> |
| 24 | #include <stddef.h> |
| 25 | #include <stdlib.h> |
| 26 | |
| 27 | #include <queues/generic_queue.h> |
| 28 | |
| 29 | struct generic_queue_item_t |
| 30 | { |
| 31 | void *value; |
| 32 | struct generic_queue_item_t *previous; |
| 33 | struct generic_queue_item_t *next; |
| 34 | }; |
| 35 | |
| 36 | struct generic_queue |
| 37 | { |
| 38 | struct generic_queue_item_t *first_item; |
| 39 | struct generic_queue_item_t *last_item; |
| 40 | size_t length; |
| 41 | }; |
| 42 | |
| 43 | struct generic_queue_iterator |
| 44 | { |
| 45 | generic_queue_t *queue; |
| 46 | struct generic_queue_item_t *item; |
| 47 | bool forward; |
| 48 | }; |
| 49 | |
| 50 | generic_queue_t *generic_queue_new(void) |
| 51 | { |
| 52 | return (generic_queue_t *)calloc(1, sizeof(generic_queue_t)); |
| 53 | } |
| 54 | |
| 55 | void generic_queue_free(generic_queue_t *queue, void (*free_value)(void *value)) |
| 56 | { |
| 57 | struct generic_queue_item_t *next_item; |
| 58 | |
| 59 | if (!queue) |
| 60 | return; |
| 61 | |
| 62 | while (queue->first_item) |
| 63 | { |
| 64 | if (free_value) |
| 65 | free_value(queue->first_item->value); |
| 66 | |
| 67 | next_item = queue->first_item->next; |
| 68 | free(queue->first_item); |
| 69 | queue->first_item = next_item; |
| 70 | } |
| 71 | |
| 72 | free(queue); |
| 73 | } |
| 74 | |
| 75 | void generic_queue_push(generic_queue_t *queue, void *value) |
| 76 | { |
| 77 | struct generic_queue_item_t *new_item; |
| 78 | |
| 79 | new_item = (struct generic_queue_item_t *)calloc(1, sizeof(struct generic_queue_item_t)); |
| 80 | new_item->value = value; |
| 81 | new_item->previous = queue->last_item; |
| 82 | new_item->next = NULL; |
| 83 | |
| 84 | queue->last_item = new_item; |
| 85 | queue->length++; |
| 86 | |
| 87 | if (!queue->first_item) |
| 88 | queue->first_item = new_item; |
| 89 | else |
| 90 | new_item->previous->next = new_item; |
| 91 | } |
| 92 | |
| 93 | void *generic_queue_pop(generic_queue_t *queue) |
| 94 | { |
| 95 | void *value; |
| 96 | struct generic_queue_item_t *item; |
| 97 | |
| 98 | if (!queue || !queue->last_item) |
| 99 | return NULL; |
| 100 | |
| 101 | item = queue->last_item; |
| 102 | queue->last_item = queue->last_item->previous; |
| 103 | queue->length--; |
| 104 | |
| 105 | if (queue->length == 0) |
| 106 | queue->first_item = NULL; |
| 107 | |
| 108 | value = item->value; |
| 109 | free(item); |
| 110 | |
| 111 | return value; |
| 112 | } |
| 113 | |
| 114 | void *generic_queue_peek(generic_queue_t *queue) |
| 115 | { |
| 116 | if (!queue || !queue->last_item) |
| 117 | return NULL; |
| 118 | |
| 119 | return queue->last_item->value; |
| 120 | } |
| 121 | |
| 122 | void *generic_queue_peek_first(generic_queue_t *queue) |
| 123 | { |
| 124 | if (!queue || !queue->first_item) |
| 125 | return NULL; |
| 126 | |
| 127 | return queue->first_item->value; |
| 128 | } |
| 129 | |
| 130 | void generic_queue_shift(generic_queue_t *queue, void *value) |
| 131 | { |
| 132 | struct generic_queue_item_t *new_item; |
| 133 | |
| 134 | if (!queue) |
| 135 | return; |
| 136 | |
| 137 | new_item = (struct generic_queue_item_t *)calloc(1, sizeof(struct generic_queue_item_t)); |
| 138 | new_item->value = value; |
| 139 | new_item->previous = NULL; |
| 140 | new_item->next = queue->first_item; |
| 141 | |
| 142 | queue->first_item = new_item; |
| 143 | queue->length++; |
| 144 | |
| 145 | if (!queue->last_item) |
| 146 | queue->last_item = new_item; |
| 147 | else |
| 148 | new_item->next->previous = new_item; |
| 149 | } |
| 150 | |
| 151 | void *generic_queue_unshift(generic_queue_t *queue) |
| 152 | { |
| 153 | void *value; |
| 154 | struct generic_queue_item_t *item; |
| 155 | |
| 156 | if (!queue || !queue->first_item) |
| 157 | return NULL; |
| 158 | |
| 159 | item = queue->first_item; |
| 160 | queue->first_item = queue->first_item->next; |
| 161 | queue->length--; |
| 162 | |
| 163 | if (queue->length == 0) |
| 164 | queue->last_item = NULL; |
| 165 | |
| 166 | value = item->value; |
| 167 | free(item); |
| 168 | |
| 169 | return value; |
| 170 | } |
| 171 | |
| 172 | size_t generic_queue_length(generic_queue_t *queue) |
| 173 | { |
| 174 | if (queue) |
| 175 | return queue->length; |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | void *generic_queue_remove(generic_queue_t *queue, void *value) |
| 181 | { |
| 182 | struct generic_queue_item_t *item; |
| 183 | |
| 184 | if (!queue) |
| 185 | return NULL; |
| 186 | |
| 187 | for (item = queue->first_item; item; item = item->next) |
| 188 | { |
| 189 | if (item->value == value) |
| 190 | { |
| 191 | if (item->previous) |
| 192 | item->previous->next = item->next; |
| 193 | else |
| 194 | queue->first_item = item->next; |
| 195 | |
| 196 | if (item->next) |
| 197 | item->next->previous = item->previous; |
| 198 | else |
| 199 | queue->last_item = item->previous; |
| 200 | |
| 201 | free(item); |
| 202 | queue->length--; |
| 203 | |
| 204 | return value; |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | return NULL; |
| 209 | } |
| 210 | |
| 211 | generic_queue_iterator_t *generic_queue_iterator(generic_queue_t *queue, bool forward) |
| 212 | { |
| 213 | if (queue && queue->first_item) |
| 214 | { |
| 215 | generic_queue_iterator_t *iterator; |
| 216 | |
| 217 | iterator = (generic_queue_iterator_t *)malloc(sizeof(generic_queue_iterator_t)); |
| 218 | iterator->queue = queue; |
| 219 | iterator->item = forward ? queue->first_item : queue->last_item; |
| 220 | iterator->forward = forward; |
| 221 | |
| 222 | return iterator; |
| 223 | } |
| 224 | |
| 225 | return NULL; |
| 226 | } |
| 227 | |
| 228 | generic_queue_iterator_t *generic_queue_iterator_next(generic_queue_iterator_t *iterator) |
| 229 | { |
| 230 | if (iterator) |
| 231 | { |
| 232 | struct generic_queue_item_t *item; |
| 233 | |
| 234 | item = iterator->forward ? iterator->item->next : iterator->item->previous; |
| 235 | if (item) |
| 236 | { |
| 237 | iterator->item = item; |
| 238 | return iterator; |
| 239 | } else |
| 240 | { |
| 241 | free(iterator); |
| 242 | return NULL; |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | return NULL; |
| 247 | } |
| 248 | |
| 249 | void *generic_queue_iterator_value(generic_queue_iterator_t *iterator) |
| 250 | { |
| 251 | if (iterator) |
| 252 | return iterator->item->value; |
| 253 | |
| 254 | return NULL; |
| 255 | } |
| 256 | |
| 257 | generic_queue_iterator_t *generic_queue_iterator_remove(generic_queue_iterator_t *iterator) |
| 258 | { |
| 259 | struct generic_queue_item_t *item; |
| 260 | |
| 261 | if (!iterator) |
| 262 | return NULL; |
| 263 | |
| 264 | item = iterator->forward ? iterator->queue->first_item : iterator->queue->last_item; |
| 265 | while (item) |
| 266 | { |
| 267 | if (iterator->item == item) |
| 268 | { |
| 269 | if (iterator->queue->first_item == item) |
| 270 | iterator->queue->first_item = item->next; |
| 271 | else |
| 272 | item->previous->next = item->next; |
| 273 | |
| 274 | if (iterator->queue->last_item == item) |
| 275 | iterator->queue->last_item = item->previous; |
| 276 | else |
| 277 | item->next->previous = item->previous; |
| 278 | |
| 279 | iterator->queue->length--; |
| 280 | |
| 281 | iterator->item = iterator->forward ? item->next : item->previous; |
| 282 | free(item); |
| 283 | if (iterator->item) |
| 284 | { |
| 285 | return iterator; |
| 286 | } else |
| 287 | { |
| 288 | free(iterator); |
| 289 | return NULL; |
| 290 | } |
| 291 | } |
| 292 | |
| 293 | item = iterator->forward ? item->next : item->previous; |
| 294 | } |
| 295 | |
| 296 | return iterator; |
| 297 | } |
| 298 | |
| 299 | void generic_queue_iterator_free(generic_queue_iterator_t *iterator) |
| 300 | { |
| 301 | if (iterator) |
| 302 | free(iterator); |
| 303 | } |