Mercurial > hg > xemacs-beta
annotate src/dynarr.c @ 4938:299dce99bdad
(for main branch) when freeing check against DEADBEEF_CONSTANT since that's what we use elsewhere
| author | Ben Wing <ben@xemacs.org> |
|---|---|
| date | Tue, 19 Jan 2010 11:25:37 -0600 |
| parents | 91b3d00e717f |
| children | 19a72041c5ed |
| rev | line source |
|---|---|
| 1318 | 1 /* Support for dynamic arrays. |
| 428 | 2 Copyright (C) 1993 Sun Microsystems, Inc. |
|
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3 Copyright (C) 2002, 2003, 2004, 2005 Ben Wing. |
| 428 | 4 |
| 5 This file is part of XEmacs. | |
| 6 | |
| 7 XEmacs is free software; you can redistribute it and/or modify it | |
| 8 under the terms of the GNU General Public License as published by the | |
| 9 Free Software Foundation; either version 2, or (at your option) any | |
| 10 later version. | |
| 11 | |
| 12 XEmacs is distributed in the hope that it will be useful, but WITHOUT | |
| 13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 15 for more details. | |
| 16 | |
| 17 You should have received a copy of the GNU General Public License | |
| 18 along with XEmacs; see the file COPYING. If not, write to | |
| 19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 20 Boston, MA 02111-1307, USA. */ | |
| 21 | |
| 22 /* Synched up with: Not in FSF. */ | |
| 23 | |
| 24 /* Written by Ben Wing, December 1993. */ | |
| 25 | |
| 26 /* | |
| 27 | |
| 28 A "dynamic array" is a contiguous array of fixed-size elements where there | |
| 29 is no upper limit (except available memory) on the number of elements in the | |
| 30 array. Because the elements are maintained contiguously, space is used | |
| 31 efficiently (no per-element pointers necessary) and random access to a | |
| 32 particular element is in constant time. At any one point, the block of memory | |
| 33 that holds the array has an upper limit; if this limit is exceeded, the | |
| 34 memory is realloc()ed into a new array that is twice as big. Assuming that | |
| 35 the time to grow the array is on the order of the new size of the array | |
| 36 block, this scheme has a provably constant amortized time (i.e. average | |
| 37 time over all additions). | |
| 38 | |
| 39 When you add elements or retrieve elements, pointers are used. Note that | |
| 40 the element itself (of whatever size it is), and not the pointer to it, | |
| 41 is stored in the array; thus you do not have to allocate any heap memory | |
| 42 on your own. Also, returned pointers are only guaranteed to be valid | |
| 43 until the next operation that changes the length of the array. | |
| 44 | |
| 45 This is a container object. Declare a dynamic array of a specific type | |
| 46 as follows: | |
| 47 | |
| 2367 | 48 typedef struct |
| 49 { | |
| 50 Dynarr_declare (mytype); | |
| 51 } mytype_dynarr; | |
| 428 | 52 |
| 53 Use the following functions/macros: | |
| 54 | |
| 55 void *Dynarr_new(type) | |
| 56 [MACRO] Create a new dynamic-array object, with each element of the | |
| 57 specified type. The return value is cast to (type##_dynarr). | |
| 58 This requires following the convention that types are declared in | |
| 59 such a way that this type concatenation works. In particular, TYPE | |
| 60 must be a symbol, not an arbitrary C type. | |
| 61 | |
| 62 Dynarr_add(d, el) | |
| 63 [MACRO] Add an element to the end of a dynamic array. EL is a pointer | |
| 64 to the element; the element itself is stored in the array, however. | |
| 65 No function call is performed unless the array needs to be resized. | |
| 66 | |
| 67 Dynarr_add_many(d, base, len) | |
| 68 [MACRO] Add LEN elements to the end of the dynamic array. The elements | |
| 771 | 69 should be contiguous in memory, starting at BASE. If BASE if NULL, |
| 70 just make space for the elements; don't actually add them. | |
| 428 | 71 |
| 72 Dynarr_insert_many_at_start(d, base, len) | |
| 73 [MACRO] Append LEN elements to the beginning of the dynamic array. | |
| 74 The elements should be contiguous in memory, starting at BASE. | |
| 771 | 75 If BASE if NULL, just make space for the elements; don't actually |
| 76 add them. | |
| 428 | 77 |
| 78 Dynarr_insert_many(d, base, len, start) | |
| 79 Insert LEN elements to the dynamic array starting at position | |
| 80 START. The elements should be contiguous in memory, starting at BASE. | |
| 771 | 81 If BASE if NULL, just make space for the elements; don't actually |
| 82 add them. | |
| 83 | |
| 84 Dynarr_delete(d, i) | |
| 85 [MACRO] Delete an element from the dynamic array at position I. | |
| 86 | |
| 87 Dynarr_delete_many(d, start, len) | |
| 88 Delete LEN elements from the dynamic array starting at position | |
| 89 START. | |
| 90 | |
| 91 Dynarr_delete_by_pointer(d, p) | |
| 92 [MACRO] Delete an element from the dynamic array at pointer P, | |
| 93 which must point within the block of memory that stores the data. | |
| 94 P should be obtained using Dynarr_atp(). | |
| 428 | 95 |
| 96 int Dynarr_length(d) | |
| 97 [MACRO] Return the number of elements currently in a dynamic array. | |
| 98 | |
| 99 int Dynarr_largest(d) | |
| 100 [MACRO] Return the maximum value that Dynarr_length(d) would | |
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101 ever have returned. This is used esp. in the redisplay code, |
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102 which reuses dynarrs for performance reasons. |
| 428 | 103 |
| 104 type Dynarr_at(d, i) | |
| 105 [MACRO] Return the element at the specified index (no bounds checking | |
| 106 done on the index). The element itself is returned, not a pointer | |
| 107 to it. | |
| 108 | |
| 109 type *Dynarr_atp(d, i) | |
| 110 [MACRO] Return a pointer to the element at the specified index (no | |
| 111 bounds checking done on the index). The pointer may not be valid | |
| 112 after an element is added to or removed from the array. | |
| 113 | |
| 114 Dynarr_reset(d) | |
| 115 [MACRO] Reset the length of a dynamic array to 0. | |
| 116 | |
| 117 Dynarr_free(d) | |
| 118 Destroy a dynamic array and the memory allocated to it. | |
| 119 | |
| 120 Use the following global variable: | |
| 121 | |
| 122 Dynarr_min_size | |
| 440 | 123 Minimum allowable size for a dynamic array when it is resized. |
| 428 | 124 |
| 125 */ | |
| 126 | |
| 127 #include <config.h> | |
| 128 #include "lisp.h" | |
| 129 | |
| 440 | 130 static int Dynarr_min_size = 8; |
| 428 | 131 |
| 132 static void | |
| 3210 | 133 Dynarr_realloc (Dynarr *dy, int new_size) |
| 428 | 134 { |
| 135 if (DUMPEDP (dy->base)) | |
| 136 { | |
| 3293 | 137 void *new_base = malloc (new_size * dy->elsize); |
| 3210 | 138 memcpy (new_base, dy->base, |
| 139 (dy->max < new_size ? dy->max : new_size) * dy->elsize); | |
| 428 | 140 dy->base = new_base; |
| 141 } | |
| 142 else | |
| 3210 | 143 dy->base = xrealloc (dy->base, new_size * dy->elsize); |
| 428 | 144 } |
| 145 | |
| 146 void * | |
| 147 Dynarr_newf (int elsize) | |
| 148 { | |
| 149 Dynarr *d = xnew_and_zero (Dynarr); | |
| 150 d->elsize = elsize; | |
| 151 | |
| 152 return d; | |
| 153 } | |
| 154 | |
| 3092 | 155 #ifdef NEW_GC |
| 156 DEFINE_LRECORD_IMPLEMENTATION ("dynarr", dynarr, | |
| 157 1, /*dumpable-flag*/ | |
| 158 0, 0, 0, 0, 0, | |
| 159 0, | |
| 160 Dynarr); | |
| 161 | |
| 162 static void | |
| 3210 | 163 Dynarr_lisp_realloc (Dynarr *dy, int new_size) |
| 3092 | 164 { |
| 165 void *new_base = alloc_lrecord_array (dy->elsize, new_size, dy->lisp_imp); | |
| 166 if (dy->base) | |
| 167 memcpy (new_base, dy->base, | |
| 3210 | 168 (dy->max < new_size ? dy->max : new_size) * dy->elsize); |
| 3092 | 169 dy->base = new_base; |
| 170 } | |
| 171 | |
| 172 void * | |
| 173 Dynarr_lisp_newf (int elsize, | |
| 174 const struct lrecord_implementation *dynarr_imp, | |
| 175 const struct lrecord_implementation *imp) | |
| 176 { | |
| 177 Dynarr *d = (Dynarr *) alloc_lrecord (sizeof (Dynarr), dynarr_imp); | |
| 178 d->elsize = elsize; | |
| 179 d->lisp_imp = imp; | |
| 180 | |
| 181 return d; | |
| 182 } | |
| 183 #endif /* not NEW_GC */ | |
| 184 | |
| 428 | 185 void |
| 2367 | 186 Dynarr_resize (void *d, Elemcount size) |
| 428 | 187 { |
| 188 int newsize; | |
| 189 double multiplier; | |
| 1318 | 190 Dynarr *dy = (Dynarr *) Dynarr_verify (d); |
| 428 | 191 |
| 192 if (dy->max <= 8) | |
| 193 multiplier = 2; | |
| 194 else | |
| 195 multiplier = 1.5; | |
| 196 | |
| 197 for (newsize = dy->max; newsize < size;) | |
| 198 newsize = max (Dynarr_min_size, (int) (multiplier * newsize)); | |
| 199 | |
| 200 /* Don't do anything if the array is already big enough. */ | |
| 201 if (newsize > dy->max) | |
| 202 { | |
| 3092 | 203 #ifdef NEW_GC |
| 204 if (dy->lisp_imp) | |
| 205 Dynarr_lisp_realloc (dy, newsize); | |
| 206 else | |
| 3210 | 207 Dynarr_realloc (dy, newsize); |
| 3092 | 208 #else /* not NEW_GC */ |
| 3210 | 209 Dynarr_realloc (dy, newsize); |
| 3092 | 210 #endif /* not NEW_GC */ |
| 428 | 211 dy->max = newsize; |
| 212 } | |
| 213 } | |
| 214 | |
| 215 /* Add a number of contiguous elements to the array starting at START. */ | |
| 216 void | |
| 442 | 217 Dynarr_insert_many (void *d, const void *el, int len, int start) |
| 428 | 218 { |
| 793 | 219 Dynarr *dy = (Dynarr *) Dynarr_verify (d); |
| 220 | |
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221 if (dy->len + len > dy->max) |
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222 Dynarr_resize (dy, dy->len + len); |
| 1318 | 223 #if 0 |
| 224 /* WTF? We should be catching these problems. */ | |
| 428 | 225 /* Silently adjust start to be valid. */ |
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226 if (start > dy->len) |
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227 start = dy->len; |
| 428 | 228 else if (start < 0) |
| 229 start = 0; | |
| 1318 | 230 #else |
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231 /* #### This could conceivably be wrong, if code wants to access stuff |
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232 between len and largest. */ |
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233 type_checking_assert (start >= 0 && start <= dy->len); |
| 1318 | 234 #endif |
| 428 | 235 |
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236 if (start != dy->len) |
| 428 | 237 { |
| 238 memmove ((char *) dy->base + (start + len)*dy->elsize, | |
| 239 (char *) dy->base + start*dy->elsize, | |
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240 (dy->len - start)*dy->elsize); |
| 428 | 241 } |
| 771 | 242 if (el) |
| 243 memcpy ((char *) dy->base + start*dy->elsize, el, len*dy->elsize); | |
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244 dy->len += len; |
| 428 | 245 |
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246 if (dy->len > dy->largest) |
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247 dy->largest = dy->len; |
| 428 | 248 } |
| 249 | |
| 250 void | |
| 251 Dynarr_delete_many (void *d, int start, int len) | |
| 252 { | |
| 1318 | 253 Dynarr *dy = (Dynarr *) Dynarr_verify (d); |
| 428 | 254 |
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255 type_checking_assert (start >= 0 && len >= 0 && start + len <= dy->len); |
| 428 | 256 memmove ((char *) dy->base + start*dy->elsize, |
| 257 (char *) dy->base + (start + len)*dy->elsize, | |
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258 (dy->len - start - len)*dy->elsize); |
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259 dy->len -= len; |
| 428 | 260 } |
| 261 | |
| 262 void | |
| 263 Dynarr_free (void *d) | |
| 264 { | |
| 265 Dynarr *dy = (Dynarr *) d; | |
| 266 | |
| 3092 | 267 #ifdef NEW_GC |
| 268 if (dy->base && !DUMPEDP (dy->base)) | |
| 269 { | |
| 4117 | 270 if (!dy->lisp_imp) |
| 3092 | 271 xfree (dy->base, void *); |
| 272 } | |
| 273 if(!DUMPEDP (dy)) | |
| 274 { | |
| 4117 | 275 if (!dy->lisp_imp) |
| 3092 | 276 xfree (dy, Dynarr *); |
| 277 } | |
| 278 #else /* not NEW_GC */ | |
| 428 | 279 if (dy->base && !DUMPEDP (dy->base)) |
| 1726 | 280 xfree (dy->base, void *); |
| 428 | 281 if(!DUMPEDP (dy)) |
| 1726 | 282 xfree (dy, Dynarr *); |
| 3092 | 283 #endif /* not NEW_GC */ |
| 428 | 284 } |
| 285 | |
| 286 #ifdef MEMORY_USAGE_STATS | |
| 287 | |
| 288 /* Return memory usage for Dynarr D. The returned value is the total | |
| 289 amount of bytes actually being used for the Dynarr, including all | |
| 290 overhead. The extra amount of space in the Dynarr that is | |
| 291 allocated beyond what was requested is returned in DYNARR_OVERHEAD | |
| 292 in STATS. The extra amount of space that malloc() allocates beyond | |
| 293 what was requested of it is returned in MALLOC_OVERHEAD in STATS. | |
| 294 See the comment above the definition of this structure. */ | |
| 295 | |
| 665 | 296 Bytecount |
| 428 | 297 Dynarr_memory_usage (void *d, struct overhead_stats *stats) |
| 298 { | |
| 665 | 299 Bytecount total = 0; |
| 428 | 300 Dynarr *dy = (Dynarr *) d; |
| 301 | |
| 302 /* We have to be a bit tricky here because not all of the | |
| 303 memory that malloc() will claim as "requested" was actually | |
| 304 requested. */ | |
| 305 | |
| 306 if (dy->base) | |
| 307 { | |
| 665 | 308 Bytecount malloc_used = malloced_storage_size (dy->base, |
| 1318 | 309 dy->elsize * dy->max, 0); |
| 428 | 310 /* #### This may or may not be correct. Some Dynarrs would |
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311 prefer that we use dy->len instead of dy->largest here. */ |
| 1318 | 312 Bytecount was_requested = dy->elsize * dy->largest; |
| 313 Bytecount dynarr_overhead = dy->elsize * (dy->max - dy->largest); | |
| 428 | 314 |
| 315 total += malloc_used; | |
| 316 stats->was_requested += was_requested; | |
| 317 stats->dynarr_overhead += dynarr_overhead; | |
| 318 /* And the remainder must be malloc overhead. */ | |
| 319 stats->malloc_overhead += | |
| 320 malloc_used - was_requested - dynarr_overhead; | |
| 321 } | |
| 322 | |
| 323 total += malloced_storage_size (d, sizeof (*dy), stats); | |
| 324 | |
| 325 return total; | |
| 326 } | |
| 327 | |
| 328 #endif /* MEMORY_USAGE_STATS */ | |
| 2367 | 329 |
| 330 /* Version of malloc() that will be extremely efficient when allocation | |
| 331 nearly always occurs in LIFO (stack) order. | |
| 332 | |
| 333 #### Perhaps shouldn't be in this file, but where else? */ | |
| 334 | |
| 335 typedef struct | |
| 336 { | |
| 337 Dynarr_declare (char_dynarr *); | |
| 338 } char_dynarr_dynarr; | |
| 339 | |
| 340 char_dynarr_dynarr *stack_like_free_list; | |
| 341 char_dynarr_dynarr *stack_like_in_use_list; | |
| 342 | |
| 343 void * | |
| 344 stack_like_malloc (Bytecount size) | |
| 345 { | |
| 346 char_dynarr *this_one; | |
| 347 if (!stack_like_free_list) | |
| 348 { | |
| 349 stack_like_free_list = Dynarr_new2 (char_dynarr_dynarr, | |
| 350 char_dynarr *); | |
| 351 stack_like_in_use_list = Dynarr_new2 (char_dynarr_dynarr, | |
| 352 char_dynarr *); | |
| 353 } | |
| 354 | |
| 355 if (Dynarr_length (stack_like_free_list) > 0) | |
| 356 this_one = Dynarr_pop (stack_like_free_list); | |
| 357 else | |
| 358 this_one = Dynarr_new (char); | |
| 359 Dynarr_add (stack_like_in_use_list, this_one); | |
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parents:
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diff
changeset
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360 Dynarr_reset (this_one); |
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parents:
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diff
changeset
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361 Dynarr_add_many (this_one, 0, size); |
| 2367 | 362 return Dynarr_atp (this_one, 0); |
| 363 } | |
| 364 | |
| 365 void | |
| 366 stack_like_free (void *val) | |
| 367 { | |
| 368 int len = Dynarr_length (stack_like_in_use_list); | |
| 369 assert (len > 0); | |
| 370 /* The vast majority of times, we will be called in a last-in first-out | |
| 371 order, and the item at the end of the list will be the one we're | |
| 372 looking for, so just check for this first and avoid any function | |
| 373 calls. */ | |
| 374 if (Dynarr_atp (Dynarr_at (stack_like_in_use_list, len - 1), 0) == val) | |
| 375 { | |
| 376 char_dynarr *this_one = Dynarr_pop (stack_like_in_use_list); | |
| 377 Dynarr_add (stack_like_free_list, this_one); | |
| 378 } | |
| 379 else | |
| 380 { | |
| 381 /* Find the item and delete it. */ | |
| 382 int i; | |
| 383 assert (len >= 2); | |
| 384 for (i = len - 2; i >= 0; i--) | |
| 385 if (Dynarr_atp (Dynarr_at (stack_like_in_use_list, i), 0) == | |
| 386 val) | |
| 387 { | |
| 388 char_dynarr *this_one = Dynarr_at (stack_like_in_use_list, i); | |
| 389 Dynarr_add (stack_like_free_list, this_one); | |
| 390 Dynarr_delete (stack_like_in_use_list, i); | |
| 391 return; | |
| 392 } | |
| 393 | |
| 2500 | 394 ABORT (); |
| 2367 | 395 } |
| 396 } |