Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 1 | /* |
| 2 | * dict.c: dictionary of reusable strings, just used to avoid allocation |
| 3 | * and freeing operations. |
| 4 | * |
| 5 | * Copyright (C) 2003 Daniel Veillard. |
| 6 | * |
| 7 | * Permission to use, copy, modify, and distribute this software for any |
| 8 | * purpose with or without fee is hereby granted, provided that the above |
| 9 | * copyright notice and this permission notice appear in all copies. |
| 10 | * |
| 11 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED |
| 12 | * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF |
| 13 | * MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND |
| 14 | * CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER. |
| 15 | * |
| 16 | * Author: daniel@veillard.com |
| 17 | */ |
| 18 | |
| 19 | #define IN_LIBXML |
| 20 | #include "libxml.h" |
| 21 | |
| 22 | #include <string.h> |
| 23 | #include <libxml/tree.h> |
| 24 | #include <libxml/dict.h> |
| 25 | #include <libxml/xmlmemory.h> |
| 26 | #include <libxml/xmlerror.h> |
| 27 | #include <libxml/globals.h> |
| 28 | |
| 29 | #define MAX_HASH_LEN 4 |
| 30 | #define MIN_DICT_SIZE 128 |
| 31 | #define MAX_DICT_HASH 8 * 2048 |
| 32 | |
| 33 | /* #define ALLOW_REMOVAL */ |
| 34 | /* #define DEBUG_GROW */ |
| 35 | |
| 36 | /* |
| 37 | * An entry in the dictionnary |
| 38 | */ |
| 39 | typedef struct _xmlDictEntry xmlDictEntry; |
| 40 | typedef xmlDictEntry *xmlDictEntryPtr; |
| 41 | struct _xmlDictEntry { |
| 42 | struct _xmlDictEntry *next; |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 43 | const xmlChar *name; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 44 | int len; |
| 45 | int valid; |
| 46 | }; |
| 47 | |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 48 | typedef struct _xmlDictStrings xmlDictStrings; |
| 49 | typedef xmlDictStrings *xmlDictStringsPtr; |
| 50 | struct _xmlDictStrings { |
| 51 | xmlDictStringsPtr next; |
| 52 | xmlChar *free; |
| 53 | xmlChar *end; |
| 54 | int size; |
| 55 | int nbStrings; |
| 56 | xmlChar array[1]; |
| 57 | }; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 58 | /* |
| 59 | * The entire dictionnary |
| 60 | */ |
| 61 | struct _xmlDict { |
| 62 | struct _xmlDictEntry *dict; |
| 63 | int size; |
| 64 | int nbElems; |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 65 | xmlDictStringsPtr strings; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 66 | }; |
| 67 | |
| 68 | /* |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 69 | * xmlDictAddString: |
| 70 | * @dict: the dictionnary |
| 71 | * @name: the name of the userdata |
| 72 | * @len: the length of the name, if -1 it is recomputed |
| 73 | * |
| 74 | * Add the string to the array[s] |
| 75 | * |
| 76 | * Returns the pointer of the local string, or NULL in case of error. |
| 77 | */ |
| 78 | static const xmlChar * |
| 79 | xmlDictAddString(xmlDictPtr dict, const xmlChar *name, int namelen) { |
| 80 | xmlDictStringsPtr pool; |
| 81 | const xmlChar *ret; |
| 82 | int size = 0; /* + sizeof(_xmlDictStrings) == 1024 */ |
| 83 | |
| 84 | pool = dict->strings; |
| 85 | while (pool != NULL) { |
| 86 | if (pool->end - pool->free > namelen) |
| 87 | goto found_pool; |
| 88 | if (pool->size > size) size = pool->size; |
| 89 | pool = pool->next; |
| 90 | } |
| 91 | /* |
| 92 | * Not found, need to allocate |
| 93 | */ |
| 94 | if (pool == NULL) { |
| 95 | if (size == 0) size = 1000; |
| 96 | else size *= 4; /* exponential growth */ |
| 97 | if (size < 4 * namelen) |
| 98 | size = 4 * namelen; /* just in case ! */ |
| 99 | pool = (xmlDictStringsPtr) xmlMalloc(sizeof(xmlDictStrings) + size); |
| 100 | if (pool == NULL) |
| 101 | return(NULL); |
| 102 | pool->size = size; |
| 103 | pool->nbStrings = 0; |
| 104 | pool->free = &pool->array[0]; |
| 105 | pool->end = &pool->array[size]; |
| 106 | pool->next = dict->strings; |
| 107 | dict->strings = pool; |
| 108 | } |
| 109 | found_pool: |
| 110 | ret = pool->free; |
| 111 | memcpy(pool->free, name, namelen); |
| 112 | pool->free += namelen; |
| 113 | *(pool->free++) = 0; |
| 114 | return(ret); |
| 115 | } |
| 116 | |
| 117 | /* |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 118 | * xmlDictComputeKey: |
| 119 | * Calculate the hash key |
| 120 | */ |
| 121 | static unsigned long |
| 122 | xmlDictComputeKey(xmlDictPtr dict, const xmlChar *name, int namelen) { |
| 123 | unsigned long value = 0L; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 124 | |
| 125 | if (name == NULL) return(0); |
| 126 | value += 30 * (*name); |
| 127 | if (namelen > 10) { |
| 128 | value += name[namelen - 1]; |
| 129 | namelen = 10; |
| 130 | } |
| 131 | switch (namelen) { |
| 132 | case 10: value += name[9]; |
| 133 | case 9: value += name[8]; |
| 134 | case 8: value += name[7]; |
| 135 | case 7: value += name[6]; |
| 136 | case 6: value += name[5]; |
| 137 | case 5: value += name[4]; |
| 138 | case 4: value += name[3]; |
| 139 | case 3: value += name[2]; |
| 140 | case 2: value += name[1]; |
| 141 | case 1: value += name[0]; |
| 142 | default: break; |
| 143 | } |
| 144 | #if 0 |
| 145 | while ((len++ < namelen) && ((ch = *name++) != 0)) { |
| 146 | value += (unsigned long)ch; |
| 147 | } |
| 148 | #endif |
| 149 | #if 0 |
| 150 | while ((len++ < namelen) && ((ch = *name++) != 0)) { |
| 151 | value = value ^ ((value << 5) + (value >> 3) + (unsigned long)ch); |
| 152 | } |
| 153 | #endif |
| 154 | return (value % dict->size); |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * xmlDictCreate: |
| 159 | * |
| 160 | * Create a new dictionary |
| 161 | * |
| 162 | * Returns the newly created object, or NULL if an error occured. |
| 163 | */ |
| 164 | xmlDictPtr |
| 165 | xmlDictCreate(void) { |
| 166 | xmlDictPtr dict; |
| 167 | |
| 168 | dict = xmlMalloc(sizeof(xmlDict)); |
| 169 | if (dict) { |
| 170 | dict->size = MIN_DICT_SIZE; |
| 171 | dict->nbElems = 0; |
| 172 | dict->dict = xmlMalloc(MIN_DICT_SIZE * sizeof(xmlDictEntry)); |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 173 | dict->strings = NULL; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 174 | if (dict->dict) { |
| 175 | memset(dict->dict, 0, MIN_DICT_SIZE * sizeof(xmlDictEntry)); |
| 176 | return(dict); |
| 177 | } |
| 178 | xmlFree(dict); |
| 179 | } |
| 180 | return(NULL); |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * xmlDictGrow: |
| 185 | * @dict: the dictionnary |
| 186 | * @size: the new size of the dictionnary |
| 187 | * |
| 188 | * resize the dictionnary |
| 189 | * |
| 190 | * Returns 0 in case of success, -1 in case of failure |
| 191 | */ |
| 192 | static int |
| 193 | xmlDictGrow(xmlDictPtr dict, int size) { |
| 194 | unsigned long key; |
| 195 | int oldsize, i; |
| 196 | xmlDictEntryPtr iter, next; |
| 197 | struct _xmlDictEntry *olddict; |
| 198 | #ifdef DEBUG_GROW |
| 199 | unsigned long nbElem = 0; |
| 200 | #endif |
| 201 | |
| 202 | if (dict == NULL) |
| 203 | return(-1); |
| 204 | if (size < 8) |
| 205 | return(-1); |
| 206 | if (size > 8 * 2048) |
| 207 | return(-1); |
| 208 | |
| 209 | oldsize = dict->size; |
| 210 | olddict = dict->dict; |
| 211 | if (olddict == NULL) |
| 212 | return(-1); |
| 213 | |
| 214 | dict->dict = xmlMalloc(size * sizeof(xmlDictEntry)); |
| 215 | if (dict->dict == NULL) { |
| 216 | dict->dict = olddict; |
| 217 | return(-1); |
| 218 | } |
| 219 | memset(dict->dict, 0, size * sizeof(xmlDictEntry)); |
| 220 | dict->size = size; |
| 221 | |
| 222 | /* If the two loops are merged, there would be situations where |
| 223 | a new entry needs to allocated and data copied into it from |
| 224 | the main dict. So instead, we run through the array twice, first |
| 225 | copying all the elements in the main array (where we can't get |
| 226 | conflicts) and then the rest, so we only free (and don't allocate) |
| 227 | */ |
| 228 | for (i = 0; i < oldsize; i++) { |
| 229 | if (olddict[i].valid == 0) |
| 230 | continue; |
| 231 | key = xmlDictComputeKey(dict, olddict[i].name, olddict[i].len); |
| 232 | memcpy(&(dict->dict[key]), &(olddict[i]), sizeof(xmlDictEntry)); |
| 233 | dict->dict[key].next = NULL; |
| 234 | #ifdef DEBUG_GROW |
| 235 | nbElem++; |
| 236 | #endif |
| 237 | } |
| 238 | |
| 239 | for (i = 0; i < oldsize; i++) { |
| 240 | iter = olddict[i].next; |
| 241 | while (iter) { |
| 242 | next = iter->next; |
| 243 | |
| 244 | /* |
| 245 | * put back the entry in the new dict |
| 246 | */ |
| 247 | |
| 248 | key = xmlDictComputeKey(dict, iter->name, iter->len); |
| 249 | if (dict->dict[key].valid == 0) { |
| 250 | memcpy(&(dict->dict[key]), iter, sizeof(xmlDictEntry)); |
| 251 | dict->dict[key].next = NULL; |
| 252 | dict->dict[key].valid = 1; |
| 253 | xmlFree(iter); |
| 254 | } else { |
| 255 | iter->next = dict->dict[key].next; |
| 256 | dict->dict[key].next = iter; |
| 257 | } |
| 258 | |
| 259 | #ifdef DEBUG_GROW |
| 260 | nbElem++; |
| 261 | #endif |
| 262 | |
| 263 | iter = next; |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | xmlFree(olddict); |
| 268 | |
| 269 | #ifdef DEBUG_GROW |
| 270 | xmlGenericError(xmlGenericErrorContext, |
| 271 | "xmlDictGrow : from %d to %d, %d elems\n", oldsize, size, nbElem); |
| 272 | #endif |
| 273 | |
| 274 | return(0); |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * xmlDictFree: |
| 279 | * @dict: the dictionnary |
| 280 | * |
| 281 | * Free the hash @dict and its contents. The userdata is |
| 282 | * deallocated with @f if provided. |
| 283 | */ |
| 284 | void |
| 285 | xmlDictFree(xmlDictPtr dict) { |
| 286 | int i; |
| 287 | xmlDictEntryPtr iter; |
| 288 | xmlDictEntryPtr next; |
| 289 | int inside_dict = 0; |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 290 | xmlDictStringsPtr pool, nextp; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 291 | |
| 292 | if (dict == NULL) |
| 293 | return; |
| 294 | if (dict->dict) { |
Daniel Veillard | 6155d8a | 2003-08-19 15:01:28 +0000 | [diff] [blame] | 295 | for(i = 0; ((i < dict->size) && (dict->nbElems > 0)); i++) { |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 296 | iter = &(dict->dict[i]); |
| 297 | if (iter->valid == 0) |
| 298 | continue; |
| 299 | inside_dict = 1; |
| 300 | while (iter) { |
| 301 | next = iter->next; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 302 | if (!inside_dict) |
| 303 | xmlFree(iter); |
Daniel Veillard | 6155d8a | 2003-08-19 15:01:28 +0000 | [diff] [blame] | 304 | dict->nbElems--; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 305 | inside_dict = 0; |
| 306 | iter = next; |
| 307 | } |
| 308 | inside_dict = 0; |
| 309 | } |
| 310 | xmlFree(dict->dict); |
| 311 | } |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 312 | pool = dict->strings; |
| 313 | while (pool != NULL) { |
| 314 | nextp = pool->next; |
| 315 | xmlFree(pool); |
| 316 | pool = nextp; |
| 317 | } |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 318 | xmlFree(dict); |
| 319 | } |
| 320 | |
| 321 | /** |
| 322 | * xmlDictLookup: |
| 323 | * @dict: the dictionnary |
| 324 | * @name: the name of the userdata |
Daniel Veillard | 0fb1893 | 2003-09-07 09:14:37 +0000 | [diff] [blame] | 325 | * @len: the length of the name, if -1 it is recomputed |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 326 | * |
| 327 | * Add the @name to the hash @dict if not present. |
| 328 | * |
| 329 | * Returns the internal copy of the name or NULL in case of internal error |
| 330 | */ |
| 331 | const xmlChar * |
| 332 | xmlDictLookup(xmlDictPtr dict, const xmlChar *name, int len) { |
| 333 | unsigned long key, nbi = 0; |
| 334 | xmlDictEntryPtr entry; |
| 335 | xmlDictEntryPtr insert; |
| 336 | const xmlChar *ret; |
| 337 | |
Daniel Veillard | 0fb1893 | 2003-09-07 09:14:37 +0000 | [diff] [blame] | 338 | if ((dict == NULL) || (name == NULL)) |
| 339 | return(NULL); |
| 340 | |
| 341 | if (len < 0) |
| 342 | len = xmlStrlen(name); |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 343 | |
| 344 | /* |
| 345 | * Check for duplicate and insertion location. |
| 346 | */ |
| 347 | key = xmlDictComputeKey(dict, name, len); |
| 348 | if (dict->dict[key].valid == 0) { |
| 349 | insert = NULL; |
| 350 | } else { |
| 351 | for (insert = &(dict->dict[key]); insert->next != NULL; |
| 352 | insert = insert->next) { |
| 353 | if ((insert->len == len) && |
| 354 | (!xmlStrncmp(insert->name, name, len))) |
| 355 | return(insert->name); |
| 356 | nbi++; |
| 357 | } |
| 358 | if ((insert->len == len) && |
| 359 | (!xmlStrncmp(insert->name, name, len))) |
| 360 | return(insert->name); |
| 361 | } |
| 362 | |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 363 | ret = xmlDictAddString(dict, name, len); |
| 364 | if (ret == NULL) |
| 365 | return(NULL); |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 366 | if (insert == NULL) { |
| 367 | entry = &(dict->dict[key]); |
| 368 | } else { |
| 369 | entry = xmlMalloc(sizeof(xmlDictEntry)); |
| 370 | if (entry == NULL) |
| 371 | return(NULL); |
| 372 | } |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 373 | entry->name = ret; |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 374 | entry->len = len; |
| 375 | entry->next = NULL; |
| 376 | entry->valid = 1; |
| 377 | |
| 378 | |
| 379 | if (insert != NULL) |
| 380 | insert->next = entry; |
| 381 | |
| 382 | dict->nbElems++; |
| 383 | |
| 384 | if ((nbi > MAX_HASH_LEN) && |
| 385 | (dict->size <= ((MAX_DICT_HASH / 2) / MAX_HASH_LEN))) |
| 386 | xmlDictGrow(dict, MAX_HASH_LEN * 2 * dict->size); |
| 387 | /* Note that entry may have been freed at this point by xmlDictGrow */ |
| 388 | |
| 389 | return(ret); |
| 390 | } |
| 391 | |
| 392 | /** |
Daniel Veillard | 81514ba | 2003-09-16 23:17:26 +0000 | [diff] [blame] | 393 | * xmlDictOwns: |
| 394 | * @dict: the dictionnary |
| 395 | * @str: the string |
| 396 | * |
| 397 | * check if a string is owned by the disctionary |
| 398 | * |
| 399 | * Returns 1 if true, 0 if false and -1 in case of error |
| 400 | * -1 in case of error |
| 401 | */ |
| 402 | int |
| 403 | xmlDictOwns(xmlDictPtr dict, const xmlChar *str) { |
| 404 | xmlDictStringsPtr pool; |
| 405 | |
| 406 | if ((dict == NULL) || (str == NULL)) |
| 407 | return(-1); |
| 408 | pool = dict->strings; |
| 409 | while (pool != NULL) { |
| 410 | if ((str >= pool->array) && (str <= pool->free)) |
| 411 | return(1); |
| 412 | pool = pool->next; |
| 413 | } |
| 414 | return(0); |
| 415 | } |
| 416 | /** |
Daniel Veillard | 2fdbd32 | 2003-08-18 12:15:38 +0000 | [diff] [blame] | 417 | * xmlDictSize: |
| 418 | * @dict: the dictionnary |
| 419 | * |
| 420 | * Query the number of elements installed in the hash @dict. |
| 421 | * |
| 422 | * Returns the number of elements in the dictionnary or |
| 423 | * -1 in case of error |
| 424 | */ |
| 425 | int |
| 426 | xmlDictSize(xmlDictPtr dict) { |
| 427 | if (dict == NULL) |
| 428 | return(-1); |
| 429 | return(dict->nbElems); |
| 430 | } |
| 431 | |
| 432 | |