1 /* Type-safe arrays which grow dynamically.
2 Copyright (C) 2017-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 /* Pre-processor macros which act as parameters:
20
21 DYNARRAY_STRUCT
22 The struct tag of dynamic array to be defined.
23 DYNARRAY_ELEMENT
24 The type name of the element type. Elements are copied
25 as if by memcpy, and can change address as the dynamic
26 array grows.
27 DYNARRAY_PREFIX
28 The prefix of the functions which are defined.
29
30 The following parameters are optional:
31
32 DYNARRAY_ELEMENT_FREE
33 DYNARRAY_ELEMENT_FREE (E) is evaluated to deallocate the
34 contents of elements. E is of type DYNARRAY_ELEMENT *.
35 DYNARRAY_ELEMENT_INIT
36 DYNARRAY_ELEMENT_INIT (E) is evaluated to initialize a new
37 element. E is of type DYNARRAY_ELEMENT *.
38 If DYNARRAY_ELEMENT_FREE but not DYNARRAY_ELEMENT_INIT is
39 defined, new elements are automatically zero-initialized.
40 Otherwise, new elements have undefined contents.
41 DYNARRAY_INITIAL_SIZE
42 The size of the statically allocated array (default:
43 at least 2, more elements if they fit into 128 bytes).
44 Must be a preprocessor constant. If DYNARRAY_INITIAL_SIZE is 0,
45 there is no statically allocated array at, and all non-empty
46 arrays are heap-allocated.
47 DYNARRAY_FINAL_TYPE
48 The name of the type which holds the final array. If not
49 defined, is PREFIX##finalize not provided. DYNARRAY_FINAL_TYPE
50 must be a struct type, with members of type DYNARRAY_ELEMENT and
51 size_t at the start (in this order).
52
53 These macros are undefined after this header file has been
54 included.
55
56 The following types are provided (their members are private to the
57 dynarray implementation):
58
59 struct DYNARRAY_STRUCT
60
61 The following functions are provided:
62
63 void DYNARRAY_PREFIX##init (struct DYNARRAY_STRUCT *);
64 void DYNARRAY_PREFIX##free (struct DYNARRAY_STRUCT *);
65 bool DYNARRAY_PREFIX##has_failed (const struct DYNARRAY_STRUCT *);
66 void DYNARRAY_PREFIX##mark_failed (struct DYNARRAY_STRUCT *);
67 size_t DYNARRAY_PREFIX##size (const struct DYNARRAY_STRUCT *);
68 DYNARRAY_ELEMENT *DYNARRAY_PREFIX##begin (const struct DYNARRAY_STRUCT *);
69 DYNARRAY_ELEMENT *DYNARRAY_PREFIX##end (const struct DYNARRAY_STRUCT *);
70 DYNARRAY_ELEMENT *DYNARRAY_PREFIX##at (struct DYNARRAY_STRUCT *, size_t);
71 void DYNARRAY_PREFIX##add (struct DYNARRAY_STRUCT *, DYNARRAY_ELEMENT);
72 DYNARRAY_ELEMENT *DYNARRAY_PREFIX##emplace (struct DYNARRAY_STRUCT *);
73 bool DYNARRAY_PREFIX##resize (struct DYNARRAY_STRUCT *, size_t);
74 void DYNARRAY_PREFIX##remove_last (struct DYNARRAY_STRUCT *);
75 void DYNARRAY_PREFIX##clear (struct DYNARRAY_STRUCT *);
76
77 The following functions are provided are provided if the
78 prerequisites are met:
79
80 bool DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *,
81 DYNARRAY_FINAL_TYPE *);
82 (if DYNARRAY_FINAL_TYPE is defined)
83 DYNARRAY_ELEMENT *DYNARRAY_PREFIX##finalize (struct DYNARRAY_STRUCT *,
84 size_t *);
85 (if DYNARRAY_FINAL_TYPE is not defined)
86 */
87
88 #include <malloc/dynarray.h>
89
90 #include <errno.h>
91 #include <stdlib.h>
92 #include <string.h>
93
94 #ifndef DYNARRAY_STRUCT
95 # error "DYNARRAY_STRUCT must be defined"
96 #endif
97
98 #ifndef DYNARRAY_ELEMENT
99 # error "DYNARRAY_ELEMENT must be defined"
100 #endif
101
102 #ifndef DYNARRAY_PREFIX
103 # error "DYNARRAY_PREFIX must be defined"
104 #endif
105
106 #ifdef DYNARRAY_INITIAL_SIZE
107 # if DYNARRAY_INITIAL_SIZE < 0
108 # error "DYNARRAY_INITIAL_SIZE must be non-negative"
109 # endif
110 # if DYNARRAY_INITIAL_SIZE > 0
111 # define DYNARRAY_HAVE_SCRATCH 1
112 # else
113 # define DYNARRAY_HAVE_SCRATCH 0
114 # endif
115 #else
116 /* Provide a reasonable default which limits the size of
117 DYNARRAY_STRUCT. */
118 # define DYNARRAY_INITIAL_SIZE \
119 (sizeof (DYNARRAY_ELEMENT) > 64 ? 2 : 128 / sizeof (DYNARRAY_ELEMENT))
120 # define DYNARRAY_HAVE_SCRATCH 1
121 #endif
122
123 /* Public type definitions. */
124
125 /* All fields of this struct are private to the implementation. */
126 struct DYNARRAY_STRUCT
127 {
128 union
129 {
130 struct dynarray_header dynarray_abstract;
131 struct
132 {
133 /* These fields must match struct dynarray_header. */
134 size_t used;
135 size_t allocated;
136 DYNARRAY_ELEMENT *array;
137 } dynarray_header;
138 } u;
139
140 #if DYNARRAY_HAVE_SCRATCH
141 /* Initial inline allocation. */
142 DYNARRAY_ELEMENT scratch[DYNARRAY_INITIAL_SIZE];
143 #endif
144 };
145
146 /* Internal use only: Helper macros. */
147
148 /* Ensure macro-expansion of DYNARRAY_PREFIX. */
149 #define DYNARRAY_CONCAT0(prefix, name) prefix##name
150 #define DYNARRAY_CONCAT1(prefix, name) DYNARRAY_CONCAT0(prefix, name)
151 #define DYNARRAY_NAME(name) DYNARRAY_CONCAT1(DYNARRAY_PREFIX, name)
152
153 /* Use DYNARRAY_FREE instead of DYNARRAY_NAME (free),
154 so that Gnulib does not change 'free' to 'rpl_free'. */
155 #define DYNARRAY_FREE DYNARRAY_CONCAT1 (DYNARRAY_NAME (f), ree)
156
157 /* Address of the scratch buffer if any. */
158 #if DYNARRAY_HAVE_SCRATCH
159 # define DYNARRAY_SCRATCH(list) (list)->scratch
160 #else
161 # define DYNARRAY_SCRATCH(list) NULL
162 #endif
163
164 /* Internal use only: Helper functions. */
165
166 /* Internal function. Call DYNARRAY_ELEMENT_FREE with the array
167 elements. Name mangling needed due to the DYNARRAY_ELEMENT_FREE
168 macro expansion. */
169 static inline void
170 DYNARRAY_NAME (free__elements__) (DYNARRAY_ELEMENT *__dynarray_array,
171 size_t __dynarray_used)
172 {
173 #ifdef DYNARRAY_ELEMENT_FREE
174 for (size_t __dynarray_i = 0; __dynarray_i < __dynarray_used; ++__dynarray_i)
175 DYNARRAY_ELEMENT_FREE (&__dynarray_array[__dynarray_i]);
176 #endif /* DYNARRAY_ELEMENT_FREE */
177 }
178
179 /* Internal function. Free the non-scratch array allocation. */
180 static inline void
181 DYNARRAY_NAME (free__array__) (struct DYNARRAY_STRUCT *list)
182 {
183 #if DYNARRAY_HAVE_SCRATCH
184 if (list->u.dynarray_header.array != list->scratch)
185 free (list->u.dynarray_header.array);
186 #else
187 free (list->u.dynarray_header.array);
188 #endif
189 }
190
191 /* Public functions. */
192
193 /* Initialize a dynamic array object. This must be called before any
194 use of the object. */
195 __attribute_nonnull__ ((1))
196 static void
197 DYNARRAY_NAME (init) (struct DYNARRAY_STRUCT *list)
198 {
199 list->u.dynarray_header.used = 0;
200 list->u.dynarray_header.allocated = DYNARRAY_INITIAL_SIZE;
201 list->u.dynarray_header.array = DYNARRAY_SCRATCH (list);
202 }
203
204 /* Deallocate the dynamic array and its elements. */
205 __attribute_maybe_unused__ __attribute_nonnull__ ((1))
206 static void
207 DYNARRAY_FREE (struct DYNARRAY_STRUCT *list)
208 {
209 DYNARRAY_NAME (free__elements__)
210 (list->u.dynarray_header.array, list->u.dynarray_header.used);
211 DYNARRAY_NAME (free__array__) (list);
212 DYNARRAY_NAME (init) (list);
213 }
214
215 /* Return true if the dynamic array is in an error state. */
216 __attribute_nonnull__ ((1))
217 static inline bool
218 DYNARRAY_NAME (has_failed) (const struct DYNARRAY_STRUCT *list)
219 {
220 return list->u.dynarray_header.allocated == __dynarray_error_marker ();
221 }
222
223 /* Mark the dynamic array as failed. All elements are deallocated as
224 a side effect. */
225 __attribute_nonnull__ ((1))
226 static void
227 DYNARRAY_NAME (mark_failed) (struct DYNARRAY_STRUCT *list)
228 {
229 DYNARRAY_NAME (free__elements__)
230 (list->u.dynarray_header.array, list->u.dynarray_header.used);
231 DYNARRAY_NAME (free__array__) (list);
232 list->u.dynarray_header.array = DYNARRAY_SCRATCH (list);
233 list->u.dynarray_header.used = 0;
234 list->u.dynarray_header.allocated = __dynarray_error_marker ();
235 }
236
237 /* Return the number of elements which have been added to the dynamic
238 array. */
239 __attribute_nonnull__ ((1))
240 static inline size_t
241 DYNARRAY_NAME (size) (const struct DYNARRAY_STRUCT *list)
242 {
243 return list->u.dynarray_header.used;
244 }
245
246 /* Return a pointer to the array element at INDEX. Terminate the
247 process if INDEX is out of bounds. */
248 __attribute_nonnull__ ((1))
249 static inline DYNARRAY_ELEMENT *
250 DYNARRAY_NAME (at) (struct DYNARRAY_STRUCT *list, size_t index)
251 {
252 if (__glibc_unlikely (index >= DYNARRAY_NAME (size) (list)))
253 __libc_dynarray_at_failure (DYNARRAY_NAME (size) (list), index);
254 return list->u.dynarray_header.array + index;
255 }
256
257 /* Return a pointer to the first array element, if any. For a
258 zero-length array, the pointer can be NULL even though the dynamic
259 array has not entered the failure state. */
260 __attribute_nonnull__ ((1))
261 static inline DYNARRAY_ELEMENT *
262 DYNARRAY_NAME (begin) (struct DYNARRAY_STRUCT *list)
263 {
264 return list->u.dynarray_header.array;
265 }
266
267 /* Return a pointer one element past the last array element. For a
268 zero-length array, the pointer can be NULL even though the dynamic
269 array has not entered the failure state. */
270 __attribute_nonnull__ ((1))
271 static inline DYNARRAY_ELEMENT *
272 DYNARRAY_NAME (end) (struct DYNARRAY_STRUCT *list)
273 {
274 return list->u.dynarray_header.array + list->u.dynarray_header.used;
275 }
276
277 /* Internal function. Slow path for the add function below. */
278 static void
279 DYNARRAY_NAME (add__) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item)
280 {
281 if (__glibc_unlikely
282 (!__libc_dynarray_emplace_enlarge (&list->u.dynarray_abstract,
283 DYNARRAY_SCRATCH (list),
284 sizeof (DYNARRAY_ELEMENT))))
285 {
286 DYNARRAY_NAME (mark_failed) (list);
287 return;
288 }
289
290 /* Copy the new element and increase the array length. */
291 list->u.dynarray_header.array[list->u.dynarray_header.used++] = item;
292 }
293
294 /* Add ITEM at the end of the array, enlarging it by one element.
295 Mark *LIST as failed if the dynamic array allocation size cannot be
296 increased. */
297 __attribute_nonnull__ ((1))
298 static inline void
299 DYNARRAY_NAME (add) (struct DYNARRAY_STRUCT *list, DYNARRAY_ELEMENT item)
300 {
301 /* Do nothing in case of previous error. */
302 if (DYNARRAY_NAME (has_failed) (list))
303 return;
304
305 /* Enlarge the array if necessary. */
306 if (__glibc_unlikely (list->u.dynarray_header.used
307 == list->u.dynarray_header.allocated))
308 {
309 DYNARRAY_NAME (add__) (list, item);
310 return;
311 }
312
313 /* Copy the new element and increase the array length. */
314 list->u.dynarray_header.array[list->u.dynarray_header.used++] = item;
315 }
316
317 /* Internal function. Building block for the emplace functions below.
318 Assumes space for one more element in *LIST. */
319 static inline DYNARRAY_ELEMENT *
320 DYNARRAY_NAME (emplace__tail__) (struct DYNARRAY_STRUCT *list)
321 {
322 DYNARRAY_ELEMENT *result
323 = &list->u.dynarray_header.array[list->u.dynarray_header.used];
324 ++list->u.dynarray_header.used;
325 #if defined (DYNARRAY_ELEMENT_INIT)
326 DYNARRAY_ELEMENT_INIT (result);
327 #elif defined (DYNARRAY_ELEMENT_FREE)
328 memset (result, 0, sizeof (*result));
329 #endif
330 return result;
331 }
332
333 /* Internal function. Slow path for the emplace function below. */
334 static DYNARRAY_ELEMENT *
335 DYNARRAY_NAME (emplace__) (struct DYNARRAY_STRUCT *list)
336 {
337 if (__glibc_unlikely
338 (!__libc_dynarray_emplace_enlarge (&list->u.dynarray_abstract,
339 DYNARRAY_SCRATCH (list),
340 sizeof (DYNARRAY_ELEMENT))))
341 {
342 DYNARRAY_NAME (mark_failed) (list);
343 return NULL;
344 }
345 return DYNARRAY_NAME (emplace__tail__) (list);
346 }
347
348 /* Allocate a place for a new element in *LIST and return a pointer to
349 it. The pointer can be NULL if the dynamic array cannot be
350 enlarged due to a memory allocation failure. */
351 __attribute_maybe_unused__ __attribute_warn_unused_result__
352 __attribute_nonnull__ ((1))
353 static
354 /* Avoid inlining with the larger initialization code. */
355 #if !(defined (DYNARRAY_ELEMENT_INIT) || defined (DYNARRAY_ELEMENT_FREE))
356 inline
357 #endif
358 DYNARRAY_ELEMENT *
359 DYNARRAY_NAME (emplace) (struct DYNARRAY_STRUCT *list)
360 {
361 /* Do nothing in case of previous error. */
362 if (DYNARRAY_NAME (has_failed) (list))
363 return NULL;
364
365 /* Enlarge the array if necessary. */
366 if (__glibc_unlikely (list->u.dynarray_header.used
367 == list->u.dynarray_header.allocated))
368 return (DYNARRAY_NAME (emplace__) (list));
369 return DYNARRAY_NAME (emplace__tail__) (list);
370 }
371
372 /* Change the size of *LIST to SIZE. If SIZE is larger than the
373 existing size, new elements are added (which can be initialized).
374 Otherwise, the list is truncated, and elements are freed. Return
375 false on memory allocation failure (and mark *LIST as failed). */
376 __attribute_maybe_unused__ __attribute_nonnull__ ((1))
377 static bool
378 DYNARRAY_NAME (resize) (struct DYNARRAY_STRUCT *list, size_t size)
379 {
380 if (size > list->u.dynarray_header.used)
381 {
382 bool ok;
383 #if defined (DYNARRAY_ELEMENT_INIT)
384 /* The new elements have to be initialized. */
385 size_t old_size = list->u.dynarray_header.used;
386 ok = __libc_dynarray_resize (&list->u.dynarray_abstract,
387 size, DYNARRAY_SCRATCH (list),
388 sizeof (DYNARRAY_ELEMENT));
389 if (ok)
390 for (size_t i = old_size; i < size; ++i)
391 {
392 DYNARRAY_ELEMENT_INIT (&list->u.dynarray_header.array[i]);
393 }
394 #elif defined (DYNARRAY_ELEMENT_FREE)
395 /* Zero initialization is needed so that the elements can be
396 safely freed. */
397 ok = __libc_dynarray_resize_clear
398 (&list->u.dynarray_abstract, size,
399 DYNARRAY_SCRATCH (list), sizeof (DYNARRAY_ELEMENT));
400 #else
401 ok = __libc_dynarray_resize (&list->u.dynarray_abstract,
402 size, DYNARRAY_SCRATCH (list),
403 sizeof (DYNARRAY_ELEMENT));
404 #endif
405 if (__glibc_unlikely (!ok))
406 DYNARRAY_NAME (mark_failed) (list);
407 return ok;
408 }
409 else
410 {
411 /* The list has shrunk in size. Free the removed elements. */
412 DYNARRAY_NAME (free__elements__)
413 (list->u.dynarray_header.array + size,
414 list->u.dynarray_header.used - size);
415 list->u.dynarray_header.used = size;
416 return true;
417 }
418 }
419
420 /* Remove the last element of LIST if it is present. */
421 __attribute_maybe_unused__ __attribute_nonnull__ ((1))
422 static void
423 DYNARRAY_NAME (remove_last) (struct DYNARRAY_STRUCT *list)
424 {
425 /* used > 0 implies that the array is the non-failed state. */
426 if (list->u.dynarray_header.used > 0)
427 {
428 size_t new_length = list->u.dynarray_header.used - 1;
429 #ifdef DYNARRAY_ELEMENT_FREE
430 DYNARRAY_ELEMENT_FREE (&list->u.dynarray_header.array[new_length]);
431 #endif
432 list->u.dynarray_header.used = new_length;
433 }
434 }
435
436 /* Remove all elements from the list. The elements are freed, but the
437 list itself is not. */
438 __attribute_maybe_unused__ __attribute_nonnull__ ((1))
439 static void
440 DYNARRAY_NAME (clear) (struct DYNARRAY_STRUCT *list)
441 {
442 /* free__elements__ does nothing if the list is in the failed
443 state. */
444 DYNARRAY_NAME (free__elements__)
445 (list->u.dynarray_header.array, list->u.dynarray_header.used);
446 list->u.dynarray_header.used = 0;
447 }
448
449 #ifdef DYNARRAY_FINAL_TYPE
450 /* Transfer the dynamic array to a permanent location at *RESULT.
451 Returns true on success on false on allocation failure. In either
452 case, *LIST is re-initialized and can be reused. A NULL pointer is
453 stored in *RESULT if LIST refers to an empty list. On success, the
454 pointer in *RESULT is heap-allocated and must be deallocated using
455 free. */
456 __attribute_maybe_unused__ __attribute_warn_unused_result__
457 __attribute_nonnull__ ((1, 2))
458 static bool
459 DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list,
460 DYNARRAY_FINAL_TYPE *result)
461 {
462 struct dynarray_finalize_result res;
463 if (__libc_dynarray_finalize (&list->u.dynarray_abstract,
464 DYNARRAY_SCRATCH (list),
465 sizeof (DYNARRAY_ELEMENT), &res))
466 {
467 /* On success, the result owns all the data. */
468 DYNARRAY_NAME (init) (list);
469 *result = (DYNARRAY_FINAL_TYPE) { res.array, res.length };
470 return true;
471 }
472 else
473 {
474 /* On error, we need to free all data. */
475 DYNARRAY_FREE (list);
476 errno = ENOMEM;
477 return false;
478 }
479 }
480 #else /* !DYNARRAY_FINAL_TYPE */
481 /* Transfer the dynamic array to a heap-allocated array and return a
482 pointer to it. The pointer is NULL if memory allocation fails, or
483 if the array is empty, so this function should be used only for
484 arrays which are known not be empty (usually because they always
485 have a sentinel at the end). If LENGTHP is not NULL, the array
486 length is written to *LENGTHP. *LIST is re-initialized and can be
487 reused. */
488 __attribute_maybe_unused__ __attribute_warn_unused_result__
489 __attribute_nonnull__ ((1))
490 static DYNARRAY_ELEMENT *
491 DYNARRAY_NAME (finalize) (struct DYNARRAY_STRUCT *list, size_t *lengthp)
492 {
493 struct dynarray_finalize_result res;
494 if (__libc_dynarray_finalize (&list->u.dynarray_abstract,
495 DYNARRAY_SCRATCH (list),
496 sizeof (DYNARRAY_ELEMENT), &res))
497 {
498 /* On success, the result owns all the data. */
499 DYNARRAY_NAME (init) (list);
500 if (lengthp != NULL)
501 *lengthp = res.length;
502 return res.array;
503 }
504 else
505 {
506 /* On error, we need to free all data. */
507 DYNARRAY_FREE (list);
508 errno = ENOMEM;
509 return NULL;
510 }
511 }
512 #endif /* !DYNARRAY_FINAL_TYPE */
513
514 /* Undo macro definitions. */
515
516 #undef DYNARRAY_CONCAT0
517 #undef DYNARRAY_CONCAT1
518 #undef DYNARRAY_NAME
519 #undef DYNARRAY_SCRATCH
520 #undef DYNARRAY_HAVE_SCRATCH
521
522 #undef DYNARRAY_STRUCT
523 #undef DYNARRAY_ELEMENT
524 #undef DYNARRAY_PREFIX
525 #undef DYNARRAY_ELEMENT_FREE
526 #undef DYNARRAY_ELEMENT_INIT
527 #undef DYNARRAY_INITIAL_SIZE
528 #undef DYNARRAY_FINAL_TYPE