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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: darray.h,v 1.7 2004/04/08 01:36:11 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 | |
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30 | #ifndef MLIB_DARRAY_H |
31 | #define MLIB_DARRAY_H |
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32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include <stdio.h> |
40 | #include <stdlib.h> |
41 | #include <string.h> |
42 | |
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43 | #ifndef MLIB_ALLOC_H |
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44 | # include "alloc.h" |
45 | #endif |
46 | |
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47 | #ifndef MLIB_EXC_H |
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48 | # include "exc.h" |
49 | #endif |
50 | |
51 | /*----- Various important constants ---------------------------------------*/ |
52 | |
53 | /* --- @DAEXC_UFLOW@, @DAEXC_OFLOW@ --- * |
54 | * |
55 | * Underflow and overflow exceptions raised by @DA_SHIFT@, and by @DA_POP@ |
56 | * and @DA_SHIFT@. |
57 | */ |
58 | |
59 | #define DAEXC_UFLOW EXC_ALLOCN(EXC_MLIB, 0) |
60 | #define DAEXC_OFLOW EXC_ALLOCN(EXC_MLIB, 1) |
61 | |
62 | /*----- Data structures ---------------------------------------------------*/ |
63 | |
64 | /* --- Base structure for dynamic arrays --- * |
65 | * |
66 | * An actual array has a `vector' @v@ in addition to this data (which is |
67 | * tucked away in the @b@ member). The vector contains the actual storage |
68 | * for the array elements. |
69 | * |
70 | * The vector pointer @v@ potentially points somewhere in the middle of the |
71 | * allocated storage. The @off@ member explains how far into the storage the |
72 | * vector points. The allocated storage is sufficient for @sz + off@ items |
73 | * to be stored. Valid array indices are integers between 0 (inclusive) and |
74 | * @len@ (exclusive). Thus, from @v@ onwards, there is space for @sz@ |
75 | * elements, and of these, @sz - len@ are currently not considered to be |
76 | * within the array's bounds. |
77 | * |
78 | * The @push@ and @unshift@ counts record how many times these operations |
79 | * have been performed since the last extension of the array. They are used |
80 | * by the extension algorithm to decide how to position the data offset. |
81 | * |
82 | * Try to use the access macros rather than the structure members. |
83 | */ |
84 | |
85 | typedef struct da_base { |
86 | size_t sz; /* Size of allocated vector */ |
87 | size_t len; /* Length of useful portion */ |
88 | size_t off; /* Offset of @v@ into space */ |
89 | unsigned push, unshift; /* Pushes/unshifts since growth */ |
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90 | arena *a; /* Pointer to allocation arena */ |
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91 | } da_base; |
92 | |
93 | /* --- @DA_DECL@ --- * |
94 | * |
95 | * Arguments: @atype@ = type name for the array |
96 | * @type@ = item type for the array |
97 | * |
98 | * Use: Declares a structure for decribing a dynamic array. |
99 | */ |
100 | |
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101 | #define DA_DECL(type_v, type) \ |
102 | typedef struct type_v { da_base b; type *v; } type_v |
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103 | |
104 | /*----- Initialization, creation and destruction --------------------------*/ |
105 | |
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106 | #define DA_INIT { { 0, 0, 0, 0, 0, &arena_stdlib }, 0 } |
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107 | |
108 | /* --- @DA_CREATE@ --- * |
109 | * |
110 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
111 | * |
112 | * Use: Initializes an array block. |
113 | */ |
114 | |
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115 | #define DA_CREATE(aa) do { \ |
116 | (aa)->b.sz = (aa)->b.len = 0; \ |
117 | (aa)->b.off = 0; \ |
118 | (aa)->b.push = (aa)->b.unshift = 0; \ |
119 | (aa)->b.a = &arena_stdlib; \ |
120 | (aa)->v = 0; \ |
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121 | } while (0) |
122 | |
123 | /* --- @DA_DESTROY@ --- * |
124 | * |
125 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
126 | * |
127 | * Use: Destroys an array. The array is left valid but empty. |
128 | */ |
129 | |
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130 | #define DA_DESTROY(aa) do { \ |
131 | if ((aa)->v) \ |
132 | x_free((aa)->b.a, (aa)->v - (aa)->b.off); \ |
133 | DA_CREATE(aa); \ |
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134 | } while (0) |
135 | |
136 | /*----- Storage reservation -----------------------------------------------*/ |
137 | |
138 | /* --- @DA_ENSURE@ --- * |
139 | * |
140 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
141 | * @n@ = required number of spare items in the array |
142 | * |
143 | * Use: Ensures that there are at least @n@ spare slots at the end of |
144 | * the array. |
145 | */ |
146 | |
147 | #define DA_ENSURE(a, n) do { \ |
148 | size_t _n = (n); \ |
149 | if (_n > (a)->b.sz - (a)->b.len) \ |
150 | (a)->v = da_ensure(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
151 | else \ |
152 | (a)->b.push += _n; \ |
153 | } while (0) |
154 | |
155 | /* --- @DA_SHUNT@ --- * |
156 | * |
157 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
158 | * @n@ = required number of spare items in the array |
159 | * |
160 | * Use: Ensures that there are at least @n@ spare slots at the start |
161 | * of the array. |
162 | */ |
163 | |
164 | #define DA_SHUNT(a, n) do { \ |
165 | size_t _n = (n); \ |
166 | if (_n > (a)->b.off) \ |
167 | (a)->v = da_shunt(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
168 | else \ |
169 | (a)->b.unshift += _n; \ |
170 | } while (0) |
171 | |
172 | /* --- @DA_TIDY@ --- * |
173 | * |
174 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
175 | * |
176 | * Use: Reduces the amount of storage required by an array to its |
177 | * minimum possible. |
178 | */ |
179 | |
180 | #define DA_TIDY(a) ((a)->v = da_tidy(&(a)->b, (a)->v, sizeof((a)->v[0]))) |
181 | |
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182 | /* --- @DA_RESET@ --- * |
183 | * |
184 | * Arguments: @a@ = pointer to array block |
185 | * |
186 | * Use: Removes all the items from the named array. This might not |
187 | * be a good idea. No storage is freed. |
188 | */ |
189 | |
190 | #define DA_RESET(a) ((a)->b.len = 0) |
191 | |
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192 | /*----- Access operations -------------------------------------------------*/ |
193 | |
194 | /* --- @DA@ --- * |
195 | * |
196 | * Arguments: @a@ = pointer to array block |
197 | * |
198 | * Use: Expands to a reference to the array proper. Given an array |
199 | * @a@, item @i@ may be located using the expression @DA(a)[i]@. |
200 | */ |
201 | |
202 | #define DA(a) ((a)->v + 0) |
203 | |
204 | /* --- @DA_LEN@ --- * |
205 | * |
206 | * Arguments: @a@ = pointer to array block |
207 | * |
208 | * Use: Expands to the number of elements in the array. Elements are |
209 | * assigned integer indices in the half-open interval |
210 | * [0, @DA_LEN(a)@). Don't change the length directly; use |
211 | * @DA_EXTEND@ instead. |
212 | */ |
213 | |
214 | #define DA_LEN(a) ((a)->b.len + 0) |
215 | |
216 | /* --- @DA_SPARE@ --- * |
217 | * |
218 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
219 | * |
220 | * Use: Evaluates to the number of spare array elements above the |
221 | * end of the array. |
222 | */ |
223 | |
224 | #define DA_SPARE(a) ((a)->b.sz - (a)->b.len) |
225 | |
226 | /* --- @DA_INCLUDE@ --- * |
227 | * |
228 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
229 | * @i@ = index into array |
230 | * |
231 | * Use: Extends the array (if necessary) so that it includes the |
232 | * index @i@. |
233 | */ |
234 | |
235 | #define DA_INCLUDE(a, i) do { \ |
236 | size_t _i = (i); \ |
237 | size_t _len = DA_LEN(a); \ |
238 | if (_i >= _len) { \ |
239 | size_t _nn = _i - _len + 1; \ |
240 | DA_ENSURE(a, _nn); \ |
241 | DA_UNSAFE_EXTEND(a, _nn); \ |
242 | } \ |
243 | } while (0) |
244 | |
245 | /* --- @DA_OFFSET@ --- * |
246 | * |
247 | * Arguments: @a@ = pointer to array block |
248 | * |
249 | * Use: Evaluates to the number of spare elements before the |
250 | * beginning of the array. Don't modify the offset directly; |
251 | * use @DA_SLIDE@ instead. |
252 | */ |
253 | |
254 | #define DA_OFFSET(a) ((a)->b.off + 0) |
255 | |
256 | /* --- @DA_EXTEND@ --- * |
257 | * |
258 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
259 | * @n@ = number of slots to add (multiply evaluated) |
260 | * |
261 | * Use: Extends the end of the array by @n@ elements. The exception |
262 | * @DAEXC_OFLOW@ is thrown if there is not enough space for the |
263 | * new elements (i.e., @n > DA_SPARE(a)@) -- call @DA_ENSURE@ to |
264 | * prevent this from happening. The integer @n@ may be |
265 | * negative; @DAEXC_UFLOW@ is called if @n < DA_LEN(a)@. |
266 | */ |
267 | |
268 | #define DA_EXTEND(a, n) do { \ |
269 | if ((n) > 0 && (n) > DA_SPARE(a)) \ |
270 | THROW(DAEXC_OFLOW); \ |
271 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
272 | THROW(DAEXC_UFLOW); \ |
273 | DA_UNSAFE_EXTEND(a, n); \ |
274 | } while (0) |
275 | |
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276 | /* --- @DA_UNSAFE_EXTEND@ --- * |
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277 | * |
278 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
279 | * @n@ = number of slots to add (multiply evaluated) |
280 | * |
281 | * Use: As for @DA_EXTEND@, only it doesn't check for errors. |
282 | */ |
283 | |
284 | #define DA_UNSAFE_EXTEND(a, n) do { \ |
285 | (a)->b.len += (n); \ |
286 | } while (0) |
287 | |
288 | /* --- @DA_SLIDE@ --- * |
289 | * |
290 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
291 | * @n@ = number of positions to slide the array (multiply |
292 | * evaluated) |
293 | * |
294 | * |
295 | * Use: Slides the array elements by @n@ positions. A positive @n@ |
296 | * slides upwards, introducing new elements at the bottom; a |
297 | * negative @n@ slides downwards, removing low-numbered |
298 | * elements. Formally, what was at index @i - n@ before the |
299 | * slide is moved to index @i@. It is an error to slide by more |
300 | * than @DA_OFFSET(a)@ or less than @-DA_LEN(a)@. The exception |
301 | * @DAEXC_OFLOW@ is raised in the former case, and @DAEXC_UFLOW@ |
302 | * in the latter. |
303 | */ |
304 | |
305 | #define DA_SLIDE(a, n) do { \ |
306 | if ((n) > 0 && (n) > DA_OFFSET(a)) \ |
307 | THROW(DAEXC_OFLOW); \ |
308 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
309 | THROW(DAEXC_UFLOW); \ |
310 | DA_UNSAFE_SLIDE((a), (n)); \ |
311 | } while (0) |
312 | |
313 | /* --- @DA_UNSAFE_SLIDE@ --- * |
314 | * |
315 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
316 | * @n@ = number of positions to slide the array (multiply |
317 | * evaluated) |
318 | * |
319 | * Use: As for @DA_SLIDE@, only it doesn't check for errors. |
320 | */ |
321 | |
322 | #define DA_UNSAFE_SLIDE(a, n) do { \ |
323 | (a)->v -= (n); \ |
324 | (a)->b.len += (n); \ |
325 | (a)->b.sz += (n); \ |
326 | (a)->b.off -= (n); \ |
327 | } while (0) |
328 | |
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329 | /* --- @DA_SHRINK@ --- * |
330 | * |
331 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
332 | * @n@ = number of slots to remove (multiply evaluated) |
333 | * |
334 | * Use: As for @DA_EXTEND@, with the sense of the argument reversed. |
335 | */ |
336 | |
337 | #define DA_SHRINK(a, n) do { \ |
338 | if ((n) > 0 && (n) > DA_LEN(a)) \ |
339 | THROW(DAEXC_UFLOW); \ |
340 | else if ((n) < 0 && -(n) > DA_SPARE(a)) \ |
341 | THROW(DAEXC_OFLOW); \ |
342 | DA_UNSAFE_SHRINK(a, n); \ |
343 | } while (0) |
344 | |
345 | /* --- @DA_UNSAFE_SHRINK@ --- * |
346 | * |
347 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
348 | * @n@ = number of slots to add (multiply evaluated) |
349 | * |
350 | * Use: As for @DA_SHRINK@, only it doesn't check for errors. |
351 | */ |
352 | |
353 | #define DA_UNSAFE_SHRINK(a, n) do { \ |
354 | (a)->b.len -= (n); \ |
355 | } while (0) |
356 | |
357 | /* --- @DA_UNSLIDE@ --- * |
358 | * |
359 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
360 | * @n@ = number of positions to slide the array (multiply |
361 | * evaluated) |
362 | * |
363 | * |
364 | * Use: As for @DA_SLIDE@, only in the other direction. |
365 | */ |
366 | |
367 | #define DA_UNSLIDE(a, n) do { \ |
368 | if ((n) > 0 && (n) > DA_LEN(a)) \ |
369 | THROW(DAEXC_UFLOW); \ |
370 | else if ((n) < 0 && -(n) > DA_OFFSET(a)) \ |
371 | THROW(DAEXC_OFLOW); \ |
372 | DA_UNSAFE_UNSLIDE((a), (n)); \ |
373 | } while (0) |
374 | |
375 | /* --- @DA_UNSAFE_UNSLIDE@ --- * |
376 | * |
377 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
378 | * @n@ = number of positions to slide the array (multiply |
379 | * evaluated) |
380 | * |
381 | * Use: As for @DA_UNSLIDE@, only it doesn't check for errors. |
382 | */ |
383 | |
384 | #define DA_UNSAFE_UNSLIDE(a, n) do { \ |
385 | (a)->v += (n); \ |
386 | (a)->b.len -= (n); \ |
387 | (a)->b.sz -= (n); \ |
388 | (a)->b.off += (n); \ |
389 | } while (0) |
390 | |
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391 | /*----- Stack-like operations ---------------------------------------------*/ |
392 | |
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393 | /* --- @DA_FIRST@ --- * |
394 | * |
395 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
396 | * |
397 | * Use: Evaluates to the initial element in array @a@. It is unsafe |
398 | * to do this if the array is empty. The array is not changed. |
399 | */ |
400 | |
401 | #define DA_FIRST(a) (DA(a)[0]) |
402 | |
403 | /* --- @DA_LAST@ --- * |
404 | * |
405 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
406 | * |
407 | * Use: Evaluates to the final element in array @a@. It is unsafe |
408 | * to do this if the array is empty. The array is not changed. |
409 | */ |
410 | |
411 | #define DA_LAST(a) (DA(a)[(a)->b.len - 1]) |
412 | |
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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) \ |
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465 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
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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 |