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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: darray.h,v 1.5 2000/06/17 10:37:39 mdw Exp $ |
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4 | * |
5 | * Dynamically growing dense arrays |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: darray.h,v $ |
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33 | * Revision 1.5 2000/06/17 10:37:39 mdw |
34 | * Add support for arena management. |
35 | * |
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36 | * Revision 1.4 1999/12/10 23:42:04 mdw |
37 | * Change header file guard names. |
38 | * |
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39 | * Revision 1.3 1999/11/05 14:32:43 mdw |
40 | * Minor change in argument naming. |
41 | * |
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42 | * Revision 1.2 1999/10/29 22:59:22 mdw |
43 | * New array adjustment macros for unsigned arguments. |
44 | * |
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45 | * Revision 1.1 1999/10/22 22:37:26 mdw |
46 | * New dynamic array implementation replaces `dynarray.h'. |
47 | * |
48 | */ |
49 | |
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50 | #ifndef MLIB_DARRAY_H |
51 | #define MLIB_DARRAY_H |
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52 | |
53 | #ifdef __cplusplus |
54 | extern "C" { |
55 | #endif |
56 | |
57 | /*----- Header files ------------------------------------------------------*/ |
58 | |
59 | #include <stdio.h> |
60 | #include <stdlib.h> |
61 | #include <string.h> |
62 | |
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63 | #ifndef MLIB_ALLOC_H |
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64 | # include "alloc.h" |
65 | #endif |
66 | |
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67 | #ifndef MLIB_EXC_H |
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68 | # include "exc.h" |
69 | #endif |
70 | |
71 | /*----- Various important constants ---------------------------------------*/ |
72 | |
73 | /* --- @DAEXC_UFLOW@, @DAEXC_OFLOW@ --- * |
74 | * |
75 | * Underflow and overflow exceptions raised by @DA_SHIFT@, and by @DA_POP@ |
76 | * and @DA_SHIFT@. |
77 | */ |
78 | |
79 | #define DAEXC_UFLOW EXC_ALLOCN(EXC_MLIB, 0) |
80 | #define DAEXC_OFLOW EXC_ALLOCN(EXC_MLIB, 1) |
81 | |
82 | /*----- Data structures ---------------------------------------------------*/ |
83 | |
84 | /* --- Base structure for dynamic arrays --- * |
85 | * |
86 | * An actual array has a `vector' @v@ in addition to this data (which is |
87 | * tucked away in the @b@ member). The vector contains the actual storage |
88 | * for the array elements. |
89 | * |
90 | * The vector pointer @v@ potentially points somewhere in the middle of the |
91 | * allocated storage. The @off@ member explains how far into the storage the |
92 | * vector points. The allocated storage is sufficient for @sz + off@ items |
93 | * to be stored. Valid array indices are integers between 0 (inclusive) and |
94 | * @len@ (exclusive). Thus, from @v@ onwards, there is space for @sz@ |
95 | * elements, and of these, @sz - len@ are currently not considered to be |
96 | * within the array's bounds. |
97 | * |
98 | * The @push@ and @unshift@ counts record how many times these operations |
99 | * have been performed since the last extension of the array. They are used |
100 | * by the extension algorithm to decide how to position the data offset. |
101 | * |
102 | * Try to use the access macros rather than the structure members. |
103 | */ |
104 | |
105 | typedef struct da_base { |
106 | size_t sz; /* Size of allocated vector */ |
107 | size_t len; /* Length of useful portion */ |
108 | size_t off; /* Offset of @v@ into space */ |
109 | unsigned push, unshift; /* Pushes/unshifts since growth */ |
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110 | arena *a; /* Pointer to allocation arena */ |
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111 | } da_base; |
112 | |
113 | /* --- @DA_DECL@ --- * |
114 | * |
115 | * Arguments: @atype@ = type name for the array |
116 | * @type@ = item type for the array |
117 | * |
118 | * Use: Declares a structure for decribing a dynamic array. |
119 | */ |
120 | |
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121 | #define DA_DECL(type_v, type) \ |
122 | typedef struct type_v { da_base b; type *v; } type_v |
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123 | |
124 | /*----- Initialization, creation and destruction --------------------------*/ |
125 | |
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126 | #define DA_INIT { { 0, 0, 0, 0, 0, &arena_stdlib }, 0 } |
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127 | |
128 | /* --- @DA_CREATE@ --- * |
129 | * |
130 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
131 | * |
132 | * Use: Initializes an array block. |
133 | */ |
134 | |
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135 | #define DA_CREATE(aa) do { \ |
136 | (aa)->b.sz = (aa)->b.len = 0; \ |
137 | (aa)->b.off = 0; \ |
138 | (aa)->b.push = (aa)->b.unshift = 0; \ |
139 | (aa)->b.a = &arena_stdlib; \ |
140 | (aa)->v = 0; \ |
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141 | } while (0) |
142 | |
143 | /* --- @DA_DESTROY@ --- * |
144 | * |
145 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
146 | * |
147 | * Use: Destroys an array. The array is left valid but empty. |
148 | */ |
149 | |
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150 | #define DA_DESTROY(aa) do { \ |
151 | if ((aa)->v) \ |
152 | x_free((aa)->b.a, (aa)->v - (aa)->b.off); \ |
153 | DA_CREATE(aa); \ |
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154 | } while (0) |
155 | |
156 | /*----- Storage reservation -----------------------------------------------*/ |
157 | |
158 | /* --- @DA_ENSURE@ --- * |
159 | * |
160 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
161 | * @n@ = required number of spare items in the array |
162 | * |
163 | * Use: Ensures that there are at least @n@ spare slots at the end of |
164 | * the array. |
165 | */ |
166 | |
167 | #define DA_ENSURE(a, n) do { \ |
168 | size_t _n = (n); \ |
169 | if (_n > (a)->b.sz - (a)->b.len) \ |
170 | (a)->v = da_ensure(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
171 | else \ |
172 | (a)->b.push += _n; \ |
173 | } while (0) |
174 | |
175 | /* --- @DA_SHUNT@ --- * |
176 | * |
177 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
178 | * @n@ = required number of spare items in the array |
179 | * |
180 | * Use: Ensures that there are at least @n@ spare slots at the start |
181 | * of the array. |
182 | */ |
183 | |
184 | #define DA_SHUNT(a, n) do { \ |
185 | size_t _n = (n); \ |
186 | if (_n > (a)->b.off) \ |
187 | (a)->v = da_shunt(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
188 | else \ |
189 | (a)->b.unshift += _n; \ |
190 | } while (0) |
191 | |
192 | /* --- @DA_TIDY@ --- * |
193 | * |
194 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
195 | * |
196 | * Use: Reduces the amount of storage required by an array to its |
197 | * minimum possible. |
198 | */ |
199 | |
200 | #define DA_TIDY(a) ((a)->v = da_tidy(&(a)->b, (a)->v, sizeof((a)->v[0]))) |
201 | |
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202 | /* --- @DA_RESET@ --- * |
203 | * |
204 | * Arguments: @a@ = pointer to array block |
205 | * |
206 | * Use: Removes all the items from the named array. This might not |
207 | * be a good idea. No storage is freed. |
208 | */ |
209 | |
210 | #define DA_RESET(a) ((a)->b.len = 0) |
211 | |
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212 | /*----- Access operations -------------------------------------------------*/ |
213 | |
214 | /* --- @DA@ --- * |
215 | * |
216 | * Arguments: @a@ = pointer to array block |
217 | * |
218 | * Use: Expands to a reference to the array proper. Given an array |
219 | * @a@, item @i@ may be located using the expression @DA(a)[i]@. |
220 | */ |
221 | |
222 | #define DA(a) ((a)->v + 0) |
223 | |
224 | /* --- @DA_LEN@ --- * |
225 | * |
226 | * Arguments: @a@ = pointer to array block |
227 | * |
228 | * Use: Expands to the number of elements in the array. Elements are |
229 | * assigned integer indices in the half-open interval |
230 | * [0, @DA_LEN(a)@). Don't change the length directly; use |
231 | * @DA_EXTEND@ instead. |
232 | */ |
233 | |
234 | #define DA_LEN(a) ((a)->b.len + 0) |
235 | |
236 | /* --- @DA_SPARE@ --- * |
237 | * |
238 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
239 | * |
240 | * Use: Evaluates to the number of spare array elements above the |
241 | * end of the array. |
242 | */ |
243 | |
244 | #define DA_SPARE(a) ((a)->b.sz - (a)->b.len) |
245 | |
246 | /* --- @DA_INCLUDE@ --- * |
247 | * |
248 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
249 | * @i@ = index into array |
250 | * |
251 | * Use: Extends the array (if necessary) so that it includes the |
252 | * index @i@. |
253 | */ |
254 | |
255 | #define DA_INCLUDE(a, i) do { \ |
256 | size_t _i = (i); \ |
257 | size_t _len = DA_LEN(a); \ |
258 | if (_i >= _len) { \ |
259 | size_t _nn = _i - _len + 1; \ |
260 | DA_ENSURE(a, _nn); \ |
261 | DA_UNSAFE_EXTEND(a, _nn); \ |
262 | } \ |
263 | } while (0) |
264 | |
265 | /* --- @DA_OFFSET@ --- * |
266 | * |
267 | * Arguments: @a@ = pointer to array block |
268 | * |
269 | * Use: Evaluates to the number of spare elements before the |
270 | * beginning of the array. Don't modify the offset directly; |
271 | * use @DA_SLIDE@ instead. |
272 | */ |
273 | |
274 | #define DA_OFFSET(a) ((a)->b.off + 0) |
275 | |
276 | /* --- @DA_EXTEND@ --- * |
277 | * |
278 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
279 | * @n@ = number of slots to add (multiply evaluated) |
280 | * |
281 | * Use: Extends the end of the array by @n@ elements. The exception |
282 | * @DAEXC_OFLOW@ is thrown if there is not enough space for the |
283 | * new elements (i.e., @n > DA_SPARE(a)@) -- call @DA_ENSURE@ to |
284 | * prevent this from happening. The integer @n@ may be |
285 | * negative; @DAEXC_UFLOW@ is called if @n < DA_LEN(a)@. |
286 | */ |
287 | |
288 | #define DA_EXTEND(a, n) do { \ |
289 | if ((n) > 0 && (n) > DA_SPARE(a)) \ |
290 | THROW(DAEXC_OFLOW); \ |
291 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
292 | THROW(DAEXC_UFLOW); \ |
293 | DA_UNSAFE_EXTEND(a, n); \ |
294 | } while (0) |
295 | |
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296 | /* --- @DA_UNSAFE_EXTEND@ --- * |
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297 | * |
298 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
299 | * @n@ = number of slots to add (multiply evaluated) |
300 | * |
301 | * Use: As for @DA_EXTEND@, only it doesn't check for errors. |
302 | */ |
303 | |
304 | #define DA_UNSAFE_EXTEND(a, n) do { \ |
305 | (a)->b.len += (n); \ |
306 | } while (0) |
307 | |
308 | /* --- @DA_SLIDE@ --- * |
309 | * |
310 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
311 | * @n@ = number of positions to slide the array (multiply |
312 | * evaluated) |
313 | * |
314 | * |
315 | * Use: Slides the array elements by @n@ positions. A positive @n@ |
316 | * slides upwards, introducing new elements at the bottom; a |
317 | * negative @n@ slides downwards, removing low-numbered |
318 | * elements. Formally, what was at index @i - n@ before the |
319 | * slide is moved to index @i@. It is an error to slide by more |
320 | * than @DA_OFFSET(a)@ or less than @-DA_LEN(a)@. The exception |
321 | * @DAEXC_OFLOW@ is raised in the former case, and @DAEXC_UFLOW@ |
322 | * in the latter. |
323 | */ |
324 | |
325 | #define DA_SLIDE(a, n) do { \ |
326 | if ((n) > 0 && (n) > DA_OFFSET(a)) \ |
327 | THROW(DAEXC_OFLOW); \ |
328 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
329 | THROW(DAEXC_UFLOW); \ |
330 | DA_UNSAFE_SLIDE((a), (n)); \ |
331 | } while (0) |
332 | |
333 | /* --- @DA_UNSAFE_SLIDE@ --- * |
334 | * |
335 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
336 | * @n@ = number of positions to slide the array (multiply |
337 | * evaluated) |
338 | * |
339 | * Use: As for @DA_SLIDE@, only it doesn't check for errors. |
340 | */ |
341 | |
342 | #define DA_UNSAFE_SLIDE(a, n) do { \ |
343 | (a)->v -= (n); \ |
344 | (a)->b.len += (n); \ |
345 | (a)->b.sz += (n); \ |
346 | (a)->b.off -= (n); \ |
347 | } while (0) |
348 | |
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349 | /* --- @DA_SHRINK@ --- * |
350 | * |
351 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
352 | * @n@ = number of slots to remove (multiply evaluated) |
353 | * |
354 | * Use: As for @DA_EXTEND@, with the sense of the argument reversed. |
355 | */ |
356 | |
357 | #define DA_SHRINK(a, n) do { \ |
358 | if ((n) > 0 && (n) > DA_LEN(a)) \ |
359 | THROW(DAEXC_UFLOW); \ |
360 | else if ((n) < 0 && -(n) > DA_SPARE(a)) \ |
361 | THROW(DAEXC_OFLOW); \ |
362 | DA_UNSAFE_SHRINK(a, n); \ |
363 | } while (0) |
364 | |
365 | /* --- @DA_UNSAFE_SHRINK@ --- * |
366 | * |
367 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
368 | * @n@ = number of slots to add (multiply evaluated) |
369 | * |
370 | * Use: As for @DA_SHRINK@, only it doesn't check for errors. |
371 | */ |
372 | |
373 | #define DA_UNSAFE_SHRINK(a, n) do { \ |
374 | (a)->b.len -= (n); \ |
375 | } while (0) |
376 | |
377 | /* --- @DA_UNSLIDE@ --- * |
378 | * |
379 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
380 | * @n@ = number of positions to slide the array (multiply |
381 | * evaluated) |
382 | * |
383 | * |
384 | * Use: As for @DA_SLIDE@, only in the other direction. |
385 | */ |
386 | |
387 | #define DA_UNSLIDE(a, n) do { \ |
388 | if ((n) > 0 && (n) > DA_LEN(a)) \ |
389 | THROW(DAEXC_UFLOW); \ |
390 | else if ((n) < 0 && -(n) > DA_OFFSET(a)) \ |
391 | THROW(DAEXC_OFLOW); \ |
392 | DA_UNSAFE_UNSLIDE((a), (n)); \ |
393 | } while (0) |
394 | |
395 | /* --- @DA_UNSAFE_UNSLIDE@ --- * |
396 | * |
397 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
398 | * @n@ = number of positions to slide the array (multiply |
399 | * evaluated) |
400 | * |
401 | * Use: As for @DA_UNSLIDE@, only it doesn't check for errors. |
402 | */ |
403 | |
404 | #define DA_UNSAFE_UNSLIDE(a, n) do { \ |
405 | (a)->v += (n); \ |
406 | (a)->b.len -= (n); \ |
407 | (a)->b.sz -= (n); \ |
408 | (a)->b.off += (n); \ |
409 | } while (0) |
410 | |
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411 | /*----- Stack-like operations ---------------------------------------------*/ |
412 | |
413 | /* --- @DA_PUSH@ --- * |
414 | * |
415 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
416 | * @x@ = item to append to the end |
417 | * |
418 | * Use: Appends @x@ as the final element in the array @a@. |
419 | */ |
420 | |
421 | #define DA_PUSH(a, x) do { \ |
422 | DA_ENSURE(a, 1); \ |
423 | DA(a)[(a)->b.len++] = x; \ |
424 | } while (0) |
425 | |
426 | /* --- @DA_POP@ --- * |
427 | * |
428 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
429 | * |
430 | * Use: Evaluates to the final element in array @a@. The element is |
431 | * removed. An exception @DAEXC_UFLOW@ is raised if there is |
432 | * no item available to pop. |
433 | */ |
434 | |
435 | #define DA_POP(a) \ |
436 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
437 | DA(a)[--(a)->b.len]) |
438 | |
439 | /* --- @DA_UNSHIFT@ --- * |
440 | * |
441 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
442 | * @x@ = the new element to insert |
443 | * |
444 | * Use: Inserts a new element at the beginning of an array. This |
445 | * might take a while. |
446 | */ |
447 | |
448 | #define DA_UNSHIFT(a, x) do { \ |
449 | DA_SHUNT(a, 1); \ |
450 | DA_UNSAFE_SLIDE(a, 1); \ |
451 | DA(a)[0] = x; \ |
452 | } while (0) |
453 | |
454 | /* --- @DA_SHIFT@ --- * |
455 | * |
456 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
457 | * |
458 | * Use: Evaluates to the initial element in array @a@. The element |
459 | * is removed, and all other elements are shifted down one |
460 | * place. The exception @DAEXC_UFLOW@ is raised if there is no |
461 | * element to return. |
462 | */ |
463 | |
464 | #define DA_SHIFT(a) \ |
465 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
466 | (a)->b.len--, \ |
467 | (a)->b.sz--, \ |
468 | (a)->b.off++, \ |
469 | *(a)->v++) |
470 | |
471 | /*----- Functions provided ------------------------------------------------*/ |
472 | |
473 | /* --- @da_ensure@ --- * |
474 | * |
475 | * Arguments: @da_base *b@ = pointer to array base structure |
476 | * @void *v@ = pointer to array vector |
477 | * @size_t sz@ = size of individual array elements |
478 | * @size_t n@ = number of items required at the end |
479 | * |
480 | * Returns: Pointer to newly allocated or adjusted array vector. |
481 | * |
482 | * Use: Extends a dynamic array to accommodate a number of new items |
483 | * at its end. This function is a helper for the @DA_ENSURE@ |
484 | * macro, which should be used by preference. |
485 | */ |
486 | |
487 | extern void *da_ensure(da_base */*b*/, void */*v*/, |
488 | size_t /*sz*/, size_t /*n*/); |
489 | |
490 | /* --- @da_shunt@ --- * |
491 | * |
492 | * Arguments: @da_base *b@ = pointer to array base structure |
493 | * @void *v@ = pointer to array vector |
494 | * @size_t sz@ = size of the array elements |
495 | * @size_t n@ = number of items required at the start |
496 | * |
497 | * Returns: Pointer to appropriately bodged vector. |
498 | * |
499 | * Use: Extends an array to accommodate items inserted at its front. |
500 | * This function is a helper for the @DA_SHUNT@ macro, which |
501 | * should be used by preference. |
502 | */ |
503 | |
504 | extern void *da_shunt(da_base */*b*/, void */*v*/, |
505 | size_t /*sz*/, size_t /*n*/); |
506 | |
507 | /* --- @da_tidy@ --- * |
508 | * |
509 | * Arguments: @da_base *b@ = pointer to array base structure |
510 | * @void *v@ = pointer to vector |
511 | * @size_t sz@ = size of the array elements |
512 | * |
513 | * Returns: Newly allocated vector. |
514 | * |
515 | * Use: Minimizes the space occupied by an array. This function is a |
516 | * helper for the @DA_TIDY@ macro, which should be used by |
517 | * preference. |
518 | */ |
519 | |
520 | extern void *da_tidy(da_base */*b*/, void */*v*/, size_t /*sz*/); |
521 | |
522 | /*----- That's all, folks -------------------------------------------------*/ |
523 | |
524 | #ifdef __cplusplus |
525 | } |
526 | #endif |
527 | |
528 | #endif |