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1 | /* -*-c-*- |
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2 | * |
3 | * Dynamically growing dense arrays |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of the mLib utilities library. |
11 | * |
12 | * mLib is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * mLib is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with mLib; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | #ifndef MLIB_DARRAY_H |
29 | #define MLIB_DARRAY_H |
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30 | |
31 | #ifdef __cplusplus |
32 | extern "C" { |
33 | #endif |
34 | |
35 | /*----- Header files ------------------------------------------------------*/ |
36 | |
37 | #include <stdio.h> |
38 | #include <stdlib.h> |
39 | #include <string.h> |
40 | |
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41 | #ifndef MLIB_ALLOC_H |
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42 | # include "alloc.h" |
43 | #endif |
44 | |
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45 | #ifndef MLIB_EXC_H |
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46 | # include "exc.h" |
47 | #endif |
48 | |
49 | /*----- Various important constants ---------------------------------------*/ |
50 | |
51 | /* --- @DAEXC_UFLOW@, @DAEXC_OFLOW@ --- * |
52 | * |
53 | * Underflow and overflow exceptions raised by @DA_SHIFT@, and by @DA_POP@ |
54 | * and @DA_SHIFT@. |
55 | */ |
56 | |
57 | #define DAEXC_UFLOW EXC_ALLOCN(EXC_MLIB, 0) |
58 | #define DAEXC_OFLOW EXC_ALLOCN(EXC_MLIB, 1) |
59 | |
60 | /*----- Data structures ---------------------------------------------------*/ |
61 | |
62 | /* --- Base structure for dynamic arrays --- * |
63 | * |
64 | * An actual array has a `vector' @v@ in addition to this data (which is |
65 | * tucked away in the @b@ member). The vector contains the actual storage |
66 | * for the array elements. |
67 | * |
68 | * The vector pointer @v@ potentially points somewhere in the middle of the |
69 | * allocated storage. The @off@ member explains how far into the storage the |
70 | * vector points. The allocated storage is sufficient for @sz + off@ items |
71 | * to be stored. Valid array indices are integers between 0 (inclusive) and |
72 | * @len@ (exclusive). Thus, from @v@ onwards, there is space for @sz@ |
73 | * elements, and of these, @sz - len@ are currently not considered to be |
74 | * within the array's bounds. |
75 | * |
76 | * The @push@ and @unshift@ counts record how many times these operations |
77 | * have been performed since the last extension of the array. They are used |
78 | * by the extension algorithm to decide how to position the data offset. |
79 | * |
80 | * Try to use the access macros rather than the structure members. |
81 | */ |
82 | |
83 | typedef struct da_base { |
84 | size_t sz; /* Size of allocated vector */ |
85 | size_t len; /* Length of useful portion */ |
86 | size_t off; /* Offset of @v@ into space */ |
87 | unsigned push, unshift; /* Pushes/unshifts since growth */ |
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88 | arena *a; /* Pointer to allocation arena */ |
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89 | } da_base; |
90 | |
91 | /* --- @DA_DECL@ --- * |
92 | * |
93 | * Arguments: @atype@ = type name for the array |
94 | * @type@ = item type for the array |
95 | * |
96 | * Use: Declares a structure for decribing a dynamic array. |
97 | */ |
98 | |
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99 | #define DA_DECL(type_v, type) \ |
100 | typedef struct type_v { da_base b; type *v; } type_v |
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101 | |
102 | /*----- Initialization, creation and destruction --------------------------*/ |
103 | |
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104 | #define DA_INIT { { 0, 0, 0, 0, 0, &arena_stdlib }, 0 } |
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105 | |
106 | /* --- @DA_CREATE@ --- * |
107 | * |
108 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
109 | * |
110 | * Use: Initializes an array block. |
111 | */ |
112 | |
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113 | #define DA_CREATE(aa) do { \ |
114 | (aa)->b.sz = (aa)->b.len = 0; \ |
115 | (aa)->b.off = 0; \ |
116 | (aa)->b.push = (aa)->b.unshift = 0; \ |
117 | (aa)->b.a = &arena_stdlib; \ |
118 | (aa)->v = 0; \ |
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119 | } while (0) |
120 | |
121 | /* --- @DA_DESTROY@ --- * |
122 | * |
123 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
124 | * |
125 | * Use: Destroys an array. The array is left valid but empty. |
126 | */ |
127 | |
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128 | #define DA_DESTROY(aa) do { \ |
129 | if ((aa)->v) \ |
130 | x_free((aa)->b.a, (aa)->v - (aa)->b.off); \ |
131 | DA_CREATE(aa); \ |
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132 | } while (0) |
133 | |
134 | /*----- Storage reservation -----------------------------------------------*/ |
135 | |
136 | /* --- @DA_ENSURE@ --- * |
137 | * |
138 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
139 | * @n@ = required number of spare items in the array |
140 | * |
141 | * Use: Ensures that there are at least @n@ spare slots at the end of |
142 | * the array. |
143 | */ |
144 | |
145 | #define DA_ENSURE(a, n) do { \ |
146 | size_t _n = (n); \ |
147 | if (_n > (a)->b.sz - (a)->b.len) \ |
148 | (a)->v = da_ensure(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
149 | else \ |
150 | (a)->b.push += _n; \ |
151 | } while (0) |
152 | |
153 | /* --- @DA_SHUNT@ --- * |
154 | * |
155 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
156 | * @n@ = required number of spare items in the array |
157 | * |
158 | * Use: Ensures that there are at least @n@ spare slots at the start |
159 | * of the array. |
160 | */ |
161 | |
162 | #define DA_SHUNT(a, n) do { \ |
163 | size_t _n = (n); \ |
164 | if (_n > (a)->b.off) \ |
165 | (a)->v = da_shunt(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
166 | else \ |
167 | (a)->b.unshift += _n; \ |
168 | } while (0) |
169 | |
170 | /* --- @DA_TIDY@ --- * |
171 | * |
172 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
173 | * |
174 | * Use: Reduces the amount of storage required by an array to its |
175 | * minimum possible. |
176 | */ |
177 | |
178 | #define DA_TIDY(a) ((a)->v = da_tidy(&(a)->b, (a)->v, sizeof((a)->v[0]))) |
179 | |
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180 | /* --- @DA_RESET@ --- * |
181 | * |
182 | * Arguments: @a@ = pointer to array block |
183 | * |
184 | * Use: Removes all the items from the named array. This might not |
185 | * be a good idea. No storage is freed. |
186 | */ |
187 | |
188 | #define DA_RESET(a) ((a)->b.len = 0) |
189 | |
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190 | /*----- Access operations -------------------------------------------------*/ |
191 | |
192 | /* --- @DA@ --- * |
193 | * |
194 | * Arguments: @a@ = pointer to array block |
195 | * |
196 | * Use: Expands to a reference to the array proper. Given an array |
197 | * @a@, item @i@ may be located using the expression @DA(a)[i]@. |
198 | */ |
199 | |
200 | #define DA(a) ((a)->v + 0) |
201 | |
202 | /* --- @DA_LEN@ --- * |
203 | * |
204 | * Arguments: @a@ = pointer to array block |
205 | * |
206 | * Use: Expands to the number of elements in the array. Elements are |
207 | * assigned integer indices in the half-open interval |
208 | * [0, @DA_LEN(a)@). Don't change the length directly; use |
209 | * @DA_EXTEND@ instead. |
210 | */ |
211 | |
212 | #define DA_LEN(a) ((a)->b.len + 0) |
213 | |
214 | /* --- @DA_SPARE@ --- * |
215 | * |
216 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
217 | * |
218 | * Use: Evaluates to the number of spare array elements above the |
219 | * end of the array. |
220 | */ |
221 | |
222 | #define DA_SPARE(a) ((a)->b.sz - (a)->b.len) |
223 | |
224 | /* --- @DA_INCLUDE@ --- * |
225 | * |
226 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
227 | * @i@ = index into array |
228 | * |
229 | * Use: Extends the array (if necessary) so that it includes the |
230 | * index @i@. |
231 | */ |
232 | |
233 | #define DA_INCLUDE(a, i) do { \ |
234 | size_t _i = (i); \ |
235 | size_t _len = DA_LEN(a); \ |
236 | if (_i >= _len) { \ |
237 | size_t _nn = _i - _len + 1; \ |
238 | DA_ENSURE(a, _nn); \ |
239 | DA_UNSAFE_EXTEND(a, _nn); \ |
240 | } \ |
241 | } while (0) |
242 | |
243 | /* --- @DA_OFFSET@ --- * |
244 | * |
245 | * Arguments: @a@ = pointer to array block |
246 | * |
247 | * Use: Evaluates to the number of spare elements before the |
248 | * beginning of the array. Don't modify the offset directly; |
249 | * use @DA_SLIDE@ instead. |
250 | */ |
251 | |
252 | #define DA_OFFSET(a) ((a)->b.off + 0) |
253 | |
254 | /* --- @DA_EXTEND@ --- * |
255 | * |
256 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
257 | * @n@ = number of slots to add (multiply evaluated) |
258 | * |
259 | * Use: Extends the end of the array by @n@ elements. The exception |
260 | * @DAEXC_OFLOW@ is thrown if there is not enough space for the |
261 | * new elements (i.e., @n > DA_SPARE(a)@) -- call @DA_ENSURE@ to |
262 | * prevent this from happening. The integer @n@ may be |
263 | * negative; @DAEXC_UFLOW@ is called if @n < DA_LEN(a)@. |
264 | */ |
265 | |
266 | #define DA_EXTEND(a, n) do { \ |
267 | if ((n) > 0 && (n) > DA_SPARE(a)) \ |
268 | THROW(DAEXC_OFLOW); \ |
269 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
270 | THROW(DAEXC_UFLOW); \ |
271 | DA_UNSAFE_EXTEND(a, n); \ |
272 | } while (0) |
273 | |
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274 | /* --- @DA_UNSAFE_EXTEND@ --- * |
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275 | * |
276 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
277 | * @n@ = number of slots to add (multiply evaluated) |
278 | * |
279 | * Use: As for @DA_EXTEND@, only it doesn't check for errors. |
280 | */ |
281 | |
282 | #define DA_UNSAFE_EXTEND(a, n) do { \ |
283 | (a)->b.len += (n); \ |
284 | } while (0) |
285 | |
286 | /* --- @DA_SLIDE@ --- * |
287 | * |
288 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
289 | * @n@ = number of positions to slide the array (multiply |
290 | * evaluated) |
291 | * |
292 | * |
293 | * Use: Slides the array elements by @n@ positions. A positive @n@ |
294 | * slides upwards, introducing new elements at the bottom; a |
295 | * negative @n@ slides downwards, removing low-numbered |
296 | * elements. Formally, what was at index @i - n@ before the |
297 | * slide is moved to index @i@. It is an error to slide by more |
298 | * than @DA_OFFSET(a)@ or less than @-DA_LEN(a)@. The exception |
299 | * @DAEXC_OFLOW@ is raised in the former case, and @DAEXC_UFLOW@ |
300 | * in the latter. |
301 | */ |
302 | |
303 | #define DA_SLIDE(a, n) do { \ |
304 | if ((n) > 0 && (n) > DA_OFFSET(a)) \ |
305 | THROW(DAEXC_OFLOW); \ |
306 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
307 | THROW(DAEXC_UFLOW); \ |
308 | DA_UNSAFE_SLIDE((a), (n)); \ |
309 | } while (0) |
310 | |
311 | /* --- @DA_UNSAFE_SLIDE@ --- * |
312 | * |
313 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
314 | * @n@ = number of positions to slide the array (multiply |
315 | * evaluated) |
316 | * |
317 | * Use: As for @DA_SLIDE@, only it doesn't check for errors. |
318 | */ |
319 | |
320 | #define DA_UNSAFE_SLIDE(a, n) do { \ |
321 | (a)->v -= (n); \ |
322 | (a)->b.len += (n); \ |
323 | (a)->b.sz += (n); \ |
324 | (a)->b.off -= (n); \ |
325 | } while (0) |
326 | |
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327 | /* --- @DA_SHRINK@ --- * |
328 | * |
329 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
330 | * @n@ = number of slots to remove (multiply evaluated) |
331 | * |
332 | * Use: As for @DA_EXTEND@, with the sense of the argument reversed. |
333 | */ |
334 | |
335 | #define DA_SHRINK(a, n) do { \ |
336 | if ((n) > 0 && (n) > DA_LEN(a)) \ |
337 | THROW(DAEXC_UFLOW); \ |
338 | else if ((n) < 0 && -(n) > DA_SPARE(a)) \ |
339 | THROW(DAEXC_OFLOW); \ |
340 | DA_UNSAFE_SHRINK(a, n); \ |
341 | } while (0) |
342 | |
343 | /* --- @DA_UNSAFE_SHRINK@ --- * |
344 | * |
345 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
346 | * @n@ = number of slots to add (multiply evaluated) |
347 | * |
348 | * Use: As for @DA_SHRINK@, only it doesn't check for errors. |
349 | */ |
350 | |
351 | #define DA_UNSAFE_SHRINK(a, n) do { \ |
352 | (a)->b.len -= (n); \ |
353 | } while (0) |
354 | |
355 | /* --- @DA_UNSLIDE@ --- * |
356 | * |
357 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
358 | * @n@ = number of positions to slide the array (multiply |
359 | * evaluated) |
360 | * |
361 | * |
362 | * Use: As for @DA_SLIDE@, only in the other direction. |
363 | */ |
364 | |
365 | #define DA_UNSLIDE(a, n) do { \ |
366 | if ((n) > 0 && (n) > DA_LEN(a)) \ |
367 | THROW(DAEXC_UFLOW); \ |
368 | else if ((n) < 0 && -(n) > DA_OFFSET(a)) \ |
369 | THROW(DAEXC_OFLOW); \ |
370 | DA_UNSAFE_UNSLIDE((a), (n)); \ |
371 | } while (0) |
372 | |
373 | /* --- @DA_UNSAFE_UNSLIDE@ --- * |
374 | * |
375 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
376 | * @n@ = number of positions to slide the array (multiply |
377 | * evaluated) |
378 | * |
379 | * Use: As for @DA_UNSLIDE@, only it doesn't check for errors. |
380 | */ |
381 | |
382 | #define DA_UNSAFE_UNSLIDE(a, n) do { \ |
383 | (a)->v += (n); \ |
384 | (a)->b.len -= (n); \ |
385 | (a)->b.sz -= (n); \ |
386 | (a)->b.off += (n); \ |
387 | } while (0) |
388 | |
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389 | /*----- Stack-like operations ---------------------------------------------*/ |
390 | |
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391 | /* --- @DA_FIRST@ --- * |
392 | * |
393 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
394 | * |
395 | * Use: Evaluates to the initial element in array @a@. It is unsafe |
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396 | * to do this if the array is empty. The array is not changed. |
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397 | */ |
398 | |
399 | #define DA_FIRST(a) (DA(a)[0]) |
400 | |
401 | /* --- @DA_LAST@ --- * |
402 | * |
403 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
404 | * |
405 | * Use: Evaluates to the final element in array @a@. It is unsafe |
406 | * to do this if the array is empty. The array is not changed. |
407 | */ |
408 | |
409 | #define DA_LAST(a) (DA(a)[(a)->b.len - 1]) |
410 | |
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411 | /* --- @DA_PUSH@ --- * |
412 | * |
413 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
414 | * @x@ = item to append to the end |
415 | * |
416 | * Use: Appends @x@ as the final element in the array @a@. |
417 | */ |
418 | |
419 | #define DA_PUSH(a, x) do { \ |
420 | DA_ENSURE(a, 1); \ |
421 | DA(a)[(a)->b.len++] = x; \ |
422 | } while (0) |
423 | |
424 | /* --- @DA_POP@ --- * |
425 | * |
426 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
427 | * |
428 | * Use: Evaluates to the final element in array @a@. The element is |
429 | * removed. An exception @DAEXC_UFLOW@ is raised if there is |
430 | * no item available to pop. |
431 | */ |
432 | |
433 | #define DA_POP(a) \ |
434 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
435 | DA(a)[--(a)->b.len]) |
436 | |
437 | /* --- @DA_UNSHIFT@ --- * |
438 | * |
439 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
440 | * @x@ = the new element to insert |
441 | * |
442 | * Use: Inserts a new element at the beginning of an array. This |
443 | * might take a while. |
444 | */ |
445 | |
446 | #define DA_UNSHIFT(a, x) do { \ |
447 | DA_SHUNT(a, 1); \ |
448 | DA_UNSAFE_SLIDE(a, 1); \ |
449 | DA(a)[0] = x; \ |
450 | } while (0) |
451 | |
452 | /* --- @DA_SHIFT@ --- * |
453 | * |
454 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
455 | * |
456 | * Use: Evaluates to the initial element in array @a@. The element |
457 | * is removed, and all other elements are shifted down one |
458 | * place. The exception @DAEXC_UFLOW@ is raised if there is no |
459 | * element to return. |
460 | */ |
461 | |
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462 | #define DA_SHIFT(a) \ |
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463 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
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464 | (a)->b.len--, \ |
465 | (a)->b.sz--, \ |
466 | (a)->b.off++, \ |
467 | *(a)->v++) |
468 | |
469 | /*----- Functions provided ------------------------------------------------*/ |
470 | |
471 | /* --- @da_ensure@ --- * |
472 | * |
473 | * Arguments: @da_base *b@ = pointer to array base structure |
474 | * @void *v@ = pointer to array vector |
475 | * @size_t sz@ = size of individual array elements |
476 | * @size_t n@ = number of items required at the end |
477 | * |
478 | * Returns: Pointer to newly allocated or adjusted array vector. |
479 | * |
480 | * Use: Extends a dynamic array to accommodate a number of new items |
481 | * at its end. This function is a helper for the @DA_ENSURE@ |
482 | * macro, which should be used by preference. |
483 | */ |
484 | |
485 | extern void *da_ensure(da_base */*b*/, void */*v*/, |
486 | size_t /*sz*/, size_t /*n*/); |
487 | |
488 | /* --- @da_shunt@ --- * |
489 | * |
490 | * Arguments: @da_base *b@ = pointer to array base structure |
491 | * @void *v@ = pointer to array vector |
492 | * @size_t sz@ = size of the array elements |
493 | * @size_t n@ = number of items required at the start |
494 | * |
495 | * Returns: Pointer to appropriately bodged vector. |
496 | * |
497 | * Use: Extends an array to accommodate items inserted at its front. |
498 | * This function is a helper for the @DA_SHUNT@ macro, which |
499 | * should be used by preference. |
500 | */ |
501 | |
502 | extern void *da_shunt(da_base */*b*/, void */*v*/, |
503 | size_t /*sz*/, size_t /*n*/); |
504 | |
505 | /* --- @da_tidy@ --- * |
506 | * |
507 | * Arguments: @da_base *b@ = pointer to array base structure |
508 | * @void *v@ = pointer to vector |
509 | * @size_t sz@ = size of the array elements |
510 | * |
511 | * Returns: Newly allocated vector. |
512 | * |
513 | * Use: Minimizes the space occupied by an array. This function is a |
514 | * helper for the @DA_TIDY@ macro, which should be used by |
515 | * preference. |
516 | */ |
517 | |
518 | extern void *da_tidy(da_base */*b*/, void */*v*/, size_t /*sz*/); |
519 | |
520 | /*----- That's all, folks -------------------------------------------------*/ |
521 | |
522 | #ifdef __cplusplus |
523 | } |
524 | #endif |
525 | |
526 | #endif |