| 1 | /* General queue data structure for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 2012-2018 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #ifndef QUEUE_H |
| 21 | #define QUEUE_H |
| 22 | |
| 23 | /* These macros implement functions and structs for a general queue. |
| 24 | Macro 'DEFINE_QUEUE_P(TYPEDEF)' is to define the new queue type for |
| 25 | TYPEDEF', and macro 'DECLARE_QUEUE_P' is to declare external queue |
| 26 | APIs. The character P indicates TYPEDEF is a pointer (P). The |
| 27 | counterpart on object (O) and integer (I) are not implemented. |
| 28 | |
| 29 | An example of their use would be, |
| 30 | |
| 31 | typedef struct foo |
| 32 | {} *foo_p; |
| 33 | |
| 34 | DEFINE_QUEUE_P (foo_p); |
| 35 | // A pointer to a queue of foo pointers. FOO_XFREE is a destructor |
| 36 | // function for foo instances in queue. |
| 37 | QUEUE(foo_p) *foo_queue = QUEUE_alloc (foo_p, foo_xfree); |
| 38 | |
| 39 | foo_p foo_var_p; |
| 40 | // Enqueue and Dequeue |
| 41 | QUEUE_enque (foo_p, foo_queue, foo_var_p); |
| 42 | foo_var_p = QUEUE_deque (foo_p, foo_queue); |
| 43 | |
| 44 | static int visit_foo (QUEUE (foo_p) *q, QUEUE_ITER (foo_p) *iter, |
| 45 | foo_p f, void *data) |
| 46 | { |
| 47 | return 1; |
| 48 | } |
| 49 | // Iterate over queue. |
| 50 | QUEUE_iterate (foo_p, foo_queue, visit_foo, ¶m); |
| 51 | |
| 52 | QUEUE_free (foo_p, foo_queue); // Free queue. */ |
| 53 | |
| 54 | /* Typical enqueue operation. Put V into queue Q. */ |
| 55 | #define QUEUE_enque(TYPE, Q, V) queue_ ## TYPE ## _enque ((Q), (V)) |
| 56 | |
| 57 | /* Typical dequeue operation. Return head element of queue Q and |
| 58 | remove it. Q must not be empty. */ |
| 59 | #define QUEUE_deque(TYPE, Q) queue_ ## TYPE ## _deque (Q) |
| 60 | |
| 61 | /* Return the head element, but don't remove it from the queue. |
| 62 | Q must not be empty. */ |
| 63 | #define QUEUE_peek(TYPE, Q) queue_ ## TYPE ## _peek (Q) |
| 64 | |
| 65 | /* Return true if queue Q is empty. */ |
| 66 | #define QUEUE_is_empty(TYPE, Q) queue_ ## TYPE ## _is_empty (Q) |
| 67 | |
| 68 | /* Allocate memory for queue. FREE_FUNC is a function to release the |
| 69 | data put in each queue element. */ |
| 70 | #define QUEUE_alloc(TYPE, FREE_FUNC) queue_ ## TYPE ## _alloc (FREE_FUNC) |
| 71 | |
| 72 | /* Length of queue Q. */ |
| 73 | #define QUEUE_length(TYPE, Q) queue_ ## TYPE ## _length (Q) |
| 74 | |
| 75 | /* Free queue Q. Q's free_func is called once for each element. */ |
| 76 | #define QUEUE_free(TYPE, Q) queue_ ## TYPE ## _free (Q) |
| 77 | |
| 78 | /* Iterate over elements in the queue Q and call function OPERATE on |
| 79 | each element. It is allowed to remove element by OPERATE. OPERATE |
| 80 | returns false to terminate the iteration and true to continue the |
| 81 | iteration. Return false if iteration is terminated by function |
| 82 | OPERATE, otherwise return true. */ |
| 83 | #define QUEUE_iterate(TYPE, Q, OPERATE, PARAM) \ |
| 84 | queue_ ## TYPE ## _iterate ((Q), (OPERATE), (PARAM)) |
| 85 | |
| 86 | /* Remove the element per the state of iterator ITER from queue Q. |
| 87 | Leave the caller to release the data in the queue element. */ |
| 88 | #define QUEUE_remove_elem(TYPE, Q, ITER) \ |
| 89 | queue_ ## TYPE ## _remove_elem ((Q), (ITER)) |
| 90 | |
| 91 | /* Define a new queue implementation. */ |
| 92 | |
| 93 | #define QUEUE(TYPE) struct queue_ ## TYPE |
| 94 | #define QUEUE_ELEM(TYPE) struct queue_elem_ ## TYPE |
| 95 | #define QUEUE_ITER(TYPE) struct queue_iter_ ## TYPE |
| 96 | #define QUEUE_ITER_FUNC(TYPE) queue_ ## TYPE ## _operate_func |
| 97 | |
| 98 | #define DEFINE_QUEUE_P(TYPE) \ |
| 99 | QUEUE_ELEM (TYPE) \ |
| 100 | { \ |
| 101 | QUEUE_ELEM (TYPE) *next; \ |
| 102 | \ |
| 103 | TYPE data; \ |
| 104 | }; \ |
| 105 | \ |
| 106 | /* Queue iterator. */ \ |
| 107 | QUEUE_ITER (TYPE) \ |
| 108 | { \ |
| 109 | /* The current element during traverse. */ \ |
| 110 | QUEUE_ELEM (TYPE) *p; \ |
| 111 | /* The previous element of P. */ \ |
| 112 | QUEUE_ELEM (TYPE) *prev; \ |
| 113 | }; \ |
| 114 | \ |
| 115 | QUEUE(TYPE) \ |
| 116 | { \ |
| 117 | /* The head and tail of the queue. */ \ |
| 118 | QUEUE_ELEM (TYPE) *head; \ |
| 119 | QUEUE_ELEM (TYPE) *tail; \ |
| 120 | /* Function to release the data put in each \ |
| 121 | queue element. */ \ |
| 122 | void (*free_func) (TYPE); \ |
| 123 | }; \ |
| 124 | \ |
| 125 | void \ |
| 126 | queue_ ## TYPE ## _enque (QUEUE (TYPE) *q, TYPE v) \ |
| 127 | { \ |
| 128 | QUEUE_ELEM (TYPE) *p = XNEW (QUEUE_ELEM (TYPE)); \ |
| 129 | \ |
| 130 | gdb_assert (q != NULL); \ |
| 131 | p->data = v; \ |
| 132 | p->next = NULL; \ |
| 133 | if (q->tail == NULL) \ |
| 134 | { \ |
| 135 | q->tail = p; \ |
| 136 | q->head = p; \ |
| 137 | } \ |
| 138 | else \ |
| 139 | { \ |
| 140 | q->tail->next = p; \ |
| 141 | q->tail = p; \ |
| 142 | } \ |
| 143 | } \ |
| 144 | \ |
| 145 | TYPE \ |
| 146 | queue_ ## TYPE ## _deque (QUEUE (TYPE) *q) \ |
| 147 | { \ |
| 148 | QUEUE_ELEM (TYPE) *p; \ |
| 149 | TYPE v; \ |
| 150 | \ |
| 151 | gdb_assert (q != NULL); \ |
| 152 | p = q->head; \ |
| 153 | gdb_assert (p != NULL); \ |
| 154 | \ |
| 155 | if (q->head == q->tail) \ |
| 156 | { \ |
| 157 | q->head = NULL; \ |
| 158 | q->tail = NULL; \ |
| 159 | } \ |
| 160 | else \ |
| 161 | q->head = q->head->next; \ |
| 162 | \ |
| 163 | v = p->data; \ |
| 164 | \ |
| 165 | xfree (p); \ |
| 166 | return v; \ |
| 167 | } \ |
| 168 | \ |
| 169 | TYPE \ |
| 170 | queue_ ## TYPE ## _peek (QUEUE (TYPE) *q) \ |
| 171 | { \ |
| 172 | gdb_assert (q != NULL); \ |
| 173 | gdb_assert (q->head != NULL); \ |
| 174 | return q->head->data; \ |
| 175 | } \ |
| 176 | \ |
| 177 | int \ |
| 178 | queue_ ## TYPE ## _is_empty (QUEUE (TYPE) *q) \ |
| 179 | { \ |
| 180 | gdb_assert (q != NULL); \ |
| 181 | return q->head == NULL; \ |
| 182 | } \ |
| 183 | \ |
| 184 | void \ |
| 185 | queue_ ## TYPE ## _remove_elem (QUEUE (TYPE) *q, \ |
| 186 | QUEUE_ITER (TYPE) *iter) \ |
| 187 | { \ |
| 188 | gdb_assert (q != NULL); \ |
| 189 | gdb_assert (iter != NULL && iter->p != NULL); \ |
| 190 | \ |
| 191 | if (iter->p == q->head || iter->p == q->tail) \ |
| 192 | { \ |
| 193 | if (iter->p == q->head) \ |
| 194 | q->head = iter->p->next; \ |
| 195 | if (iter->p == q->tail) \ |
| 196 | q->tail = iter->prev; \ |
| 197 | } \ |
| 198 | else \ |
| 199 | iter->prev->next = iter->p->next; \ |
| 200 | \ |
| 201 | xfree (iter->p); \ |
| 202 | /* Indicate that ITER->p has been deleted from QUEUE q. */ \ |
| 203 | iter->p = NULL; \ |
| 204 | } \ |
| 205 | \ |
| 206 | int \ |
| 207 | queue_ ## TYPE ## _iterate (QUEUE (TYPE) *q, \ |
| 208 | QUEUE_ITER_FUNC (TYPE) operate, \ |
| 209 | void *data) \ |
| 210 | { \ |
| 211 | QUEUE_ELEM (TYPE) *next = NULL; \ |
| 212 | QUEUE_ITER (TYPE) iter = { NULL, NULL }; \ |
| 213 | \ |
| 214 | gdb_assert (q != NULL); \ |
| 215 | \ |
| 216 | for (iter.p = q->head; iter.p != NULL; iter.p = next) \ |
| 217 | { \ |
| 218 | next = iter.p->next; \ |
| 219 | if (!operate (q, &iter, iter.p->data, data)) \ |
| 220 | return 0; \ |
| 221 | /* ITER.P was not deleted by function OPERATE. */ \ |
| 222 | if (iter.p != NULL) \ |
| 223 | iter.prev = iter.p; \ |
| 224 | } \ |
| 225 | return 1; \ |
| 226 | } \ |
| 227 | \ |
| 228 | QUEUE (TYPE) * \ |
| 229 | queue_ ## TYPE ## _alloc (void (*free_func) (TYPE)) \ |
| 230 | { \ |
| 231 | QUEUE (TYPE) *q = XNEW (QUEUE (TYPE)); \ |
| 232 | \ |
| 233 | q->head = NULL; \ |
| 234 | q->tail = NULL; \ |
| 235 | q->free_func = free_func; \ |
| 236 | return q; \ |
| 237 | } \ |
| 238 | \ |
| 239 | int \ |
| 240 | queue_ ## TYPE ## _length (QUEUE (TYPE) *q) \ |
| 241 | { \ |
| 242 | QUEUE_ELEM (TYPE) *p; \ |
| 243 | int len = 0; \ |
| 244 | \ |
| 245 | gdb_assert (q != NULL); \ |
| 246 | \ |
| 247 | for (p = q->head; p != NULL; p = p->next) \ |
| 248 | len++; \ |
| 249 | \ |
| 250 | return len; \ |
| 251 | } \ |
| 252 | \ |
| 253 | void \ |
| 254 | queue_ ## TYPE ## _free (QUEUE (TYPE) *q) \ |
| 255 | { \ |
| 256 | QUEUE_ELEM (TYPE) *p, *next; \ |
| 257 | \ |
| 258 | gdb_assert (q != NULL); \ |
| 259 | \ |
| 260 | for (p = q->head; p != NULL; p = next) \ |
| 261 | { \ |
| 262 | next = p->next; \ |
| 263 | if (q->free_func) \ |
| 264 | q->free_func (p->data); \ |
| 265 | xfree (p); \ |
| 266 | } \ |
| 267 | xfree (q); \ |
| 268 | } \ |
| 269 | |
| 270 | /* External declarations for queue functions. */ |
| 271 | #define DECLARE_QUEUE_P(TYPE) \ |
| 272 | QUEUE (TYPE); \ |
| 273 | QUEUE_ELEM (TYPE); \ |
| 274 | QUEUE_ITER (TYPE); \ |
| 275 | extern void \ |
| 276 | queue_ ## TYPE ## _enque (QUEUE (TYPE) *q, TYPE v); \ |
| 277 | extern TYPE \ |
| 278 | queue_ ## TYPE ## _deque (QUEUE (TYPE) *q); \ |
| 279 | extern int queue_ ## TYPE ## _is_empty (QUEUE (TYPE) *q); \ |
| 280 | extern QUEUE (TYPE) * \ |
| 281 | queue_ ## TYPE ## _alloc (void (*free_func) (TYPE)); \ |
| 282 | extern int queue_ ## TYPE ## _length (QUEUE (TYPE) *q); \ |
| 283 | extern TYPE \ |
| 284 | queue_ ## TYPE ## _peek (QUEUE (TYPE) *q); \ |
| 285 | extern void queue_ ## TYPE ## _free (QUEUE (TYPE) *q); \ |
| 286 | typedef int QUEUE_ITER_FUNC(TYPE) (QUEUE (TYPE) *, \ |
| 287 | QUEUE_ITER (TYPE) *, \ |
| 288 | TYPE, \ |
| 289 | void *); \ |
| 290 | extern int \ |
| 291 | queue_ ## TYPE ## _iterate (QUEUE (TYPE) *q, \ |
| 292 | QUEUE_ITER_FUNC (TYPE) operate, \ |
| 293 | void *); \ |
| 294 | extern void \ |
| 295 | queue_ ## TYPE ## _remove_elem (QUEUE (TYPE) *q, \ |
| 296 | QUEUE_ITER (TYPE) *iter); \ |
| 297 | |
| 298 | #endif /* QUEUE_H */ |