3745e24b |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: darray.h,v 1.1 1999/10/22 22:37:26 mdw Exp $ |
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 $ |
33 | * Revision 1.1 1999/10/22 22:37:26 mdw |
34 | * New dynamic array implementation replaces `dynarray.h'. |
35 | * |
36 | */ |
37 | |
38 | #ifndef DARRAY_H |
39 | #define DARRAY_H |
40 | |
41 | #ifdef __cplusplus |
42 | extern "C" { |
43 | #endif |
44 | |
45 | /*----- Header files ------------------------------------------------------*/ |
46 | |
47 | #include <stdio.h> |
48 | #include <stdlib.h> |
49 | #include <string.h> |
50 | |
51 | #ifndef ALLOC_H |
52 | # include "alloc.h" |
53 | #endif |
54 | |
55 | #ifndef EXC_H |
56 | # include "exc.h" |
57 | #endif |
58 | |
59 | /*----- Various important constants ---------------------------------------*/ |
60 | |
61 | /* --- @DAEXC_UFLOW@, @DAEXC_OFLOW@ --- * |
62 | * |
63 | * Underflow and overflow exceptions raised by @DA_SHIFT@, and by @DA_POP@ |
64 | * and @DA_SHIFT@. |
65 | */ |
66 | |
67 | #define DAEXC_UFLOW EXC_ALLOCN(EXC_MLIB, 0) |
68 | #define DAEXC_OFLOW EXC_ALLOCN(EXC_MLIB, 1) |
69 | |
70 | /*----- Data structures ---------------------------------------------------*/ |
71 | |
72 | /* --- Base structure for dynamic arrays --- * |
73 | * |
74 | * An actual array has a `vector' @v@ in addition to this data (which is |
75 | * tucked away in the @b@ member). The vector contains the actual storage |
76 | * for the array elements. |
77 | * |
78 | * The vector pointer @v@ potentially points somewhere in the middle of the |
79 | * allocated storage. The @off@ member explains how far into the storage the |
80 | * vector points. The allocated storage is sufficient for @sz + off@ items |
81 | * to be stored. Valid array indices are integers between 0 (inclusive) and |
82 | * @len@ (exclusive). Thus, from @v@ onwards, there is space for @sz@ |
83 | * elements, and of these, @sz - len@ are currently not considered to be |
84 | * within the array's bounds. |
85 | * |
86 | * The @push@ and @unshift@ counts record how many times these operations |
87 | * have been performed since the last extension of the array. They are used |
88 | * by the extension algorithm to decide how to position the data offset. |
89 | * |
90 | * Try to use the access macros rather than the structure members. |
91 | */ |
92 | |
93 | typedef struct da_base { |
94 | size_t sz; /* Size of allocated vector */ |
95 | size_t len; /* Length of useful portion */ |
96 | size_t off; /* Offset of @v@ into space */ |
97 | unsigned push, unshift; /* Pushes/unshifts since growth */ |
98 | } da_base; |
99 | |
100 | /* --- @DA_DECL@ --- * |
101 | * |
102 | * Arguments: @atype@ = type name for the array |
103 | * @type@ = item type for the array |
104 | * |
105 | * Use: Declares a structure for decribing a dynamic array. |
106 | */ |
107 | |
108 | #define DA_DECL(atype, type) \ |
109 | typedef struct atype { da_base b; type *v; } atype |
110 | |
111 | /*----- Initialization, creation and destruction --------------------------*/ |
112 | |
113 | #define DA_INIT { { 0, 0, 0, 0, 0 }, 0 } /* Standard initializer */ |
114 | |
115 | /* --- @DA_CREATE@ --- * |
116 | * |
117 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
118 | * |
119 | * Use: Initializes an array block. |
120 | */ |
121 | |
122 | #define DA_CREATE(a) do { \ |
123 | (a)->b.sz = (a)->b.len = 0; \ |
124 | (a)->b.off = 0; \ |
125 | (a)->b.push = (a)->b.unshift = 0; \ |
126 | (a)->v = 0; \ |
127 | } while (0) |
128 | |
129 | /* --- @DA_DESTROY@ --- * |
130 | * |
131 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
132 | * |
133 | * Use: Destroys an array. The array is left valid but empty. |
134 | */ |
135 | |
136 | #define DA_DESTROY(a) do { \ |
137 | if ((a)->v) \ |
138 | free((a)->v - (a)->b.off); \ |
139 | DA_CREATE(a); \ |
140 | } while (0) |
141 | |
142 | /*----- Storage reservation -----------------------------------------------*/ |
143 | |
144 | /* --- @DA_ENSURE@ --- * |
145 | * |
146 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
147 | * @n@ = required number of spare items in the array |
148 | * |
149 | * Use: Ensures that there are at least @n@ spare slots at the end of |
150 | * the array. |
151 | */ |
152 | |
153 | #define DA_ENSURE(a, n) do { \ |
154 | size_t _n = (n); \ |
155 | if (_n > (a)->b.sz - (a)->b.len) \ |
156 | (a)->v = da_ensure(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
157 | else \ |
158 | (a)->b.push += _n; \ |
159 | } while (0) |
160 | |
161 | /* --- @DA_SHUNT@ --- * |
162 | * |
163 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
164 | * @n@ = required number of spare items in the array |
165 | * |
166 | * Use: Ensures that there are at least @n@ spare slots at the start |
167 | * of the array. |
168 | */ |
169 | |
170 | #define DA_SHUNT(a, n) do { \ |
171 | size_t _n = (n); \ |
172 | if (_n > (a)->b.off) \ |
173 | (a)->v = da_shunt(&(a)->b, (a)->v, sizeof((a)->v[0]), _n); \ |
174 | else \ |
175 | (a)->b.unshift += _n; \ |
176 | } while (0) |
177 | |
178 | /* --- @DA_TIDY@ --- * |
179 | * |
180 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
181 | * |
182 | * Use: Reduces the amount of storage required by an array to its |
183 | * minimum possible. |
184 | */ |
185 | |
186 | #define DA_TIDY(a) ((a)->v = da_tidy(&(a)->b, (a)->v, sizeof((a)->v[0]))) |
187 | |
188 | /*----- Access operations -------------------------------------------------*/ |
189 | |
190 | /* --- @DA@ --- * |
191 | * |
192 | * Arguments: @a@ = pointer to array block |
193 | * |
194 | * Use: Expands to a reference to the array proper. Given an array |
195 | * @a@, item @i@ may be located using the expression @DA(a)[i]@. |
196 | */ |
197 | |
198 | #define DA(a) ((a)->v + 0) |
199 | |
200 | /* --- @DA_LEN@ --- * |
201 | * |
202 | * Arguments: @a@ = pointer to array block |
203 | * |
204 | * Use: Expands to the number of elements in the array. Elements are |
205 | * assigned integer indices in the half-open interval |
206 | * [0, @DA_LEN(a)@). Don't change the length directly; use |
207 | * @DA_EXTEND@ instead. |
208 | */ |
209 | |
210 | #define DA_LEN(a) ((a)->b.len + 0) |
211 | |
212 | /* --- @DA_SPARE@ --- * |
213 | * |
214 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
215 | * |
216 | * Use: Evaluates to the number of spare array elements above the |
217 | * end of the array. |
218 | */ |
219 | |
220 | #define DA_SPARE(a) ((a)->b.sz - (a)->b.len) |
221 | |
222 | /* --- @DA_INCLUDE@ --- * |
223 | * |
224 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
225 | * @i@ = index into array |
226 | * |
227 | * Use: Extends the array (if necessary) so that it includes the |
228 | * index @i@. |
229 | */ |
230 | |
231 | #define DA_INCLUDE(a, i) do { \ |
232 | size_t _i = (i); \ |
233 | size_t _len = DA_LEN(a); \ |
234 | if (_i >= _len) { \ |
235 | size_t _nn = _i - _len + 1; \ |
236 | DA_ENSURE(a, _nn); \ |
237 | DA_UNSAFE_EXTEND(a, _nn); \ |
238 | } \ |
239 | } while (0) |
240 | |
241 | /* --- @DA_OFFSET@ --- * |
242 | * |
243 | * Arguments: @a@ = pointer to array block |
244 | * |
245 | * Use: Evaluates to the number of spare elements before the |
246 | * beginning of the array. Don't modify the offset directly; |
247 | * use @DA_SLIDE@ instead. |
248 | */ |
249 | |
250 | #define DA_OFFSET(a) ((a)->b.off + 0) |
251 | |
252 | /* --- @DA_EXTEND@ --- * |
253 | * |
254 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
255 | * @n@ = number of slots to add (multiply evaluated) |
256 | * |
257 | * Use: Extends the end of the array by @n@ elements. The exception |
258 | * @DAEXC_OFLOW@ is thrown if there is not enough space for the |
259 | * new elements (i.e., @n > DA_SPARE(a)@) -- call @DA_ENSURE@ to |
260 | * prevent this from happening. The integer @n@ may be |
261 | * negative; @DAEXC_UFLOW@ is called if @n < DA_LEN(a)@. |
262 | */ |
263 | |
264 | #define DA_EXTEND(a, n) do { \ |
265 | if ((n) > 0 && (n) > DA_SPARE(a)) \ |
266 | THROW(DAEXC_OFLOW); \ |
267 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
268 | THROW(DAEXC_UFLOW); \ |
269 | DA_UNSAFE_EXTEND(a, n); \ |
270 | } while (0) |
271 | |
272 | /* --- @DA_EXTEND@ --- * |
273 | * |
274 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
275 | * @n@ = number of slots to add (multiply evaluated) |
276 | * |
277 | * Use: As for @DA_EXTEND@, only it doesn't check for errors. |
278 | */ |
279 | |
280 | #define DA_UNSAFE_EXTEND(a, n) do { \ |
281 | (a)->b.len += (n); \ |
282 | } while (0) |
283 | |
284 | /* --- @DA_SLIDE@ --- * |
285 | * |
286 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
287 | * @n@ = number of positions to slide the array (multiply |
288 | * evaluated) |
289 | * |
290 | * |
291 | * Use: Slides the array elements by @n@ positions. A positive @n@ |
292 | * slides upwards, introducing new elements at the bottom; a |
293 | * negative @n@ slides downwards, removing low-numbered |
294 | * elements. Formally, what was at index @i - n@ before the |
295 | * slide is moved to index @i@. It is an error to slide by more |
296 | * than @DA_OFFSET(a)@ or less than @-DA_LEN(a)@. The exception |
297 | * @DAEXC_OFLOW@ is raised in the former case, and @DAEXC_UFLOW@ |
298 | * in the latter. |
299 | */ |
300 | |
301 | #define DA_SLIDE(a, n) do { \ |
302 | if ((n) > 0 && (n) > DA_OFFSET(a)) \ |
303 | THROW(DAEXC_OFLOW); \ |
304 | else if ((n) < 0 && -(n) > DA_LEN(a)) \ |
305 | THROW(DAEXC_UFLOW); \ |
306 | DA_UNSAFE_SLIDE((a), (n)); \ |
307 | } while (0) |
308 | |
309 | /* --- @DA_UNSAFE_SLIDE@ --- * |
310 | * |
311 | * Arguments: @a@ = pointer to array block (multiply evaluated) |
312 | * @n@ = number of positions to slide the array (multiply |
313 | * evaluated) |
314 | * |
315 | * Use: As for @DA_SLIDE@, only it doesn't check for errors. |
316 | */ |
317 | |
318 | #define DA_UNSAFE_SLIDE(a, n) do { \ |
319 | (a)->v -= (n); \ |
320 | (a)->b.len += (n); \ |
321 | (a)->b.sz += (n); \ |
322 | (a)->b.off -= (n); \ |
323 | } while (0) |
324 | |
325 | /*----- Stack-like operations ---------------------------------------------*/ |
326 | |
327 | /* --- @DA_PUSH@ --- * |
328 | * |
329 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
330 | * @x@ = item to append to the end |
331 | * |
332 | * Use: Appends @x@ as the final element in the array @a@. |
333 | */ |
334 | |
335 | #define DA_PUSH(a, x) do { \ |
336 | DA_ENSURE(a, 1); \ |
337 | DA(a)[(a)->b.len++] = x; \ |
338 | } while (0) |
339 | |
340 | /* --- @DA_POP@ --- * |
341 | * |
342 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
343 | * |
344 | * Use: Evaluates to the final element in array @a@. The element is |
345 | * removed. An exception @DAEXC_UFLOW@ is raised if there is |
346 | * no item available to pop. |
347 | */ |
348 | |
349 | #define DA_POP(a) \ |
350 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
351 | DA(a)[--(a)->b.len]) |
352 | |
353 | /* --- @DA_UNSHIFT@ --- * |
354 | * |
355 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
356 | * @x@ = the new element to insert |
357 | * |
358 | * Use: Inserts a new element at the beginning of an array. This |
359 | * might take a while. |
360 | */ |
361 | |
362 | #define DA_UNSHIFT(a, x) do { \ |
363 | DA_SHUNT(a, 1); \ |
364 | DA_UNSAFE_SLIDE(a, 1); \ |
365 | DA(a)[0] = x; \ |
366 | } while (0) |
367 | |
368 | /* --- @DA_SHIFT@ --- * |
369 | * |
370 | * Arguments: @a@ = pointer to an array block (multiply evaluated) |
371 | * |
372 | * Use: Evaluates to the initial element in array @a@. The element |
373 | * is removed, and all other elements are shifted down one |
374 | * place. The exception @DAEXC_UFLOW@ is raised if there is no |
375 | * element to return. |
376 | */ |
377 | |
378 | #define DA_SHIFT(a) \ |
379 | ((a)->b.len ? ((void)0) : THROW(DAEXC_UFLOW), \ |
380 | (a)->b.len--, \ |
381 | (a)->b.sz--, \ |
382 | (a)->b.off++, \ |
383 | *(a)->v++) |
384 | |
385 | /*----- Functions provided ------------------------------------------------*/ |
386 | |
387 | /* --- @da_ensure@ --- * |
388 | * |
389 | * Arguments: @da_base *b@ = pointer to array base structure |
390 | * @void *v@ = pointer to array vector |
391 | * @size_t sz@ = size of individual array elements |
392 | * @size_t n@ = number of items required at the end |
393 | * |
394 | * Returns: Pointer to newly allocated or adjusted array vector. |
395 | * |
396 | * Use: Extends a dynamic array to accommodate a number of new items |
397 | * at its end. This function is a helper for the @DA_ENSURE@ |
398 | * macro, which should be used by preference. |
399 | */ |
400 | |
401 | extern void *da_ensure(da_base */*b*/, void */*v*/, |
402 | size_t /*sz*/, size_t /*n*/); |
403 | |
404 | /* --- @da_shunt@ --- * |
405 | * |
406 | * Arguments: @da_base *b@ = pointer to array base structure |
407 | * @void *v@ = pointer to array vector |
408 | * @size_t sz@ = size of the array elements |
409 | * @size_t n@ = number of items required at the start |
410 | * |
411 | * Returns: Pointer to appropriately bodged vector. |
412 | * |
413 | * Use: Extends an array to accommodate items inserted at its front. |
414 | * This function is a helper for the @DA_SHUNT@ macro, which |
415 | * should be used by preference. |
416 | */ |
417 | |
418 | extern void *da_shunt(da_base */*b*/, void */*v*/, |
419 | size_t /*sz*/, size_t /*n*/); |
420 | |
421 | /* --- @da_tidy@ --- * |
422 | * |
423 | * Arguments: @da_base *b@ = pointer to array base structure |
424 | * @void *v@ = pointer to vector |
425 | * @size_t sz@ = size of the array elements |
426 | * |
427 | * Returns: Newly allocated vector. |
428 | * |
429 | * Use: Minimizes the space occupied by an array. This function is a |
430 | * helper for the @DA_TIDY@ macro, which should be used by |
431 | * preference. |
432 | */ |
433 | |
434 | extern void *da_tidy(da_base */*b*/, void */*v*/, size_t /*sz*/); |
435 | |
436 | /*----- That's all, folks -------------------------------------------------*/ |
437 | |
438 | #ifdef __cplusplus |
439 | } |
440 | #endif |
441 | |
442 | #endif |