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