Victor Chang | 7322950 | 2020-09-17 13:39:19 +0100 | [diff] [blame] | 1 | // © 2016 and later: Unicode, Inc. and others. |
| 2 | // License & terms of use: http://www.unicode.org/copyright.html |
| 3 | /* |
| 4 | ****************************************************************************** |
| 5 | * Copyright (C) 1997-2015, International Business Machines |
| 6 | * Corporation and others. All Rights Reserved. |
| 7 | ****************************************************************************** |
| 8 | * Date Name Description |
| 9 | * 03/22/00 aliu Adapted from original C++ ICU Hashtable. |
| 10 | * 07/06/01 aliu Modified to support int32_t keys on |
| 11 | * platforms with sizeof(void*) < 32. |
| 12 | ****************************************************************************** |
| 13 | */ |
| 14 | |
| 15 | #ifndef UHASH_H |
| 16 | #define UHASH_H |
| 17 | |
| 18 | #include "unicode/utypes.h" |
| 19 | #include "cmemory.h" |
| 20 | #include "uelement.h" |
| 21 | #include "unicode/localpointer.h" |
| 22 | |
| 23 | /** |
| 24 | * UHashtable stores key-value pairs and does moderately fast lookup |
| 25 | * based on keys. It provides a good tradeoff between access time and |
| 26 | * storage space. As elements are added to it, it grows to accomodate |
| 27 | * them. By default, the table never shrinks, even if all elements |
| 28 | * are removed from it. |
| 29 | * |
| 30 | * Keys and values are stored as void* pointers. These void* pointers |
| 31 | * may be actual pointers to strings, objects, or any other structure |
| 32 | * in memory, or they may simply be integral values cast to void*. |
| 33 | * UHashtable doesn't care and manipulates them via user-supplied |
| 34 | * functions. These functions hash keys, compare keys, delete keys, |
| 35 | * and delete values. Some function pointers are optional (may be |
| 36 | * NULL); others must be supplied. Several prebuilt functions exist |
| 37 | * to handle common key types. |
| 38 | * |
| 39 | * UHashtable ownership of keys and values is flexible, and controlled |
| 40 | * by whether or not the key deleter and value deleter functions are |
| 41 | * set. If a void* key is actually a pointer to a deletable object, |
| 42 | * then UHashtable can be made to delete that object by setting the |
| 43 | * key deleter function pointer to a non-NULL value. If this is done, |
| 44 | * then keys passed to uhash_put() are owned by the hashtable and will |
| 45 | * be deleted by it at some point, either as keys are replaced, or |
| 46 | * when uhash_close() is finally called. The same is true of values |
| 47 | * and the value deleter function pointer. Keys passed to methods |
| 48 | * other than uhash_put() are never owned by the hashtable. |
| 49 | * |
| 50 | * NULL values are not allowed. uhash_get() returns NULL to indicate |
| 51 | * a key that is not in the table, and having a NULL value in the |
| 52 | * table would generate an ambiguous result. If a key and a NULL |
| 53 | * value is passed to uhash_put(), this has the effect of doing a |
| 54 | * uhash_remove() on that key. This keeps uhash_get(), uhash_count(), |
| 55 | * and uhash_nextElement() consistent with one another. |
| 56 | * |
| 57 | * To see everything in a hashtable, use uhash_nextElement() to |
| 58 | * iterate through its contents. Each call to this function returns a |
| 59 | * UHashElement pointer. A hash element contains a key, value, and |
| 60 | * hashcode. During iteration an element may be deleted by calling |
| 61 | * uhash_removeElement(); iteration may safely continue thereafter. |
| 62 | * The uhash_remove() function may also be safely called in |
| 63 | * mid-iteration. If uhash_put() is called during iteration, |
| 64 | * the iteration is still guaranteed to terminate reasonably, but |
| 65 | * there is no guarantee that every element will be returned or that |
| 66 | * some won't be returned more than once. |
| 67 | * |
| 68 | * Under no circumstances should the UHashElement returned by |
| 69 | * uhash_nextElement be modified directly. |
| 70 | * |
| 71 | * By default, the hashtable grows when necessary, but never shrinks, |
| 72 | * even if all items are removed. For most applications this is |
| 73 | * optimal. However, in a highly dynamic usage where memory is at a |
| 74 | * premium, the table can be set to both grow and shrink by calling |
| 75 | * uhash_setResizePolicy() with the policy U_GROW_AND_SHRINK. In a |
| 76 | * situation where memory is critical and the client wants a table |
| 77 | * that does not grow at all, the constant U_FIXED can be used. |
| 78 | */ |
| 79 | |
| 80 | /******************************************************************** |
| 81 | * Data Structures |
| 82 | ********************************************************************/ |
| 83 | |
| 84 | U_CDECL_BEGIN |
| 85 | |
| 86 | /** |
| 87 | * A key or value within a UHashtable. |
| 88 | * The hashing and comparison functions take a pointer to a |
| 89 | * UHashTok, but the deleter receives the void* pointer within it. |
| 90 | */ |
| 91 | typedef UElement UHashTok; |
| 92 | |
| 93 | /** |
| 94 | * This is a single hash element. |
| 95 | */ |
| 96 | struct UHashElement { |
| 97 | /* Reorder these elements to pack nicely if necessary */ |
| 98 | int32_t hashcode; |
| 99 | UHashTok value; |
| 100 | UHashTok key; |
| 101 | }; |
| 102 | typedef struct UHashElement UHashElement; |
| 103 | |
| 104 | /** |
| 105 | * A hashing function. |
| 106 | * @param key A key stored in a hashtable |
| 107 | * @return A NON-NEGATIVE hash code for parm. |
| 108 | */ |
| 109 | typedef int32_t U_CALLCONV UHashFunction(const UHashTok key); |
| 110 | |
| 111 | /** |
| 112 | * A key equality (boolean) comparison function. |
| 113 | */ |
| 114 | typedef UElementsAreEqual UKeyComparator; |
| 115 | |
| 116 | /** |
| 117 | * A value equality (boolean) comparison function. |
| 118 | */ |
| 119 | typedef UElementsAreEqual UValueComparator; |
| 120 | |
| 121 | /* see cmemory.h for UObjectDeleter and uprv_deleteUObject() */ |
| 122 | |
| 123 | /** |
| 124 | * This specifies whether or not, and how, the hastable resizes itself. |
| 125 | * See uhash_setResizePolicy(). |
| 126 | */ |
| 127 | enum UHashResizePolicy { |
| 128 | U_GROW, /* Grow on demand, do not shrink */ |
| 129 | U_GROW_AND_SHRINK, /* Grow and shrink on demand */ |
| 130 | U_FIXED /* Never change size */ |
| 131 | }; |
| 132 | |
| 133 | /** |
| 134 | * The UHashtable struct. Clients should treat this as an opaque data |
| 135 | * type and manipulate it only through the uhash_... API. |
| 136 | */ |
| 137 | struct UHashtable { |
| 138 | |
| 139 | /* Main key-value pair storage array */ |
| 140 | |
| 141 | UHashElement *elements; |
| 142 | |
| 143 | /* Function pointers */ |
| 144 | |
| 145 | UHashFunction *keyHasher; /* Computes hash from key. |
| 146 | * Never null. */ |
| 147 | UKeyComparator *keyComparator; /* Compares keys for equality. |
| 148 | * Never null. */ |
| 149 | UValueComparator *valueComparator; /* Compares the values for equality */ |
| 150 | |
| 151 | UObjectDeleter *keyDeleter; /* Deletes keys when required. |
| 152 | * If NULL won't do anything */ |
| 153 | UObjectDeleter *valueDeleter; /* Deletes values when required. |
| 154 | * If NULL won't do anything */ |
| 155 | |
| 156 | /* Size parameters */ |
| 157 | |
| 158 | int32_t count; /* The number of key-value pairs in this table. |
| 159 | * 0 <= count <= length. In practice we |
| 160 | * never let count == length (see code). */ |
| 161 | int32_t length; /* The physical size of the arrays hashes, keys |
| 162 | * and values. Must be prime. */ |
| 163 | |
| 164 | /* Rehashing thresholds */ |
| 165 | |
| 166 | int32_t highWaterMark; /* If count > highWaterMark, rehash */ |
| 167 | int32_t lowWaterMark; /* If count < lowWaterMark, rehash */ |
| 168 | float highWaterRatio; /* 0..1; high water as a fraction of length */ |
| 169 | float lowWaterRatio; /* 0..1; low water as a fraction of length */ |
| 170 | |
| 171 | int8_t primeIndex; /* Index into our prime table for length. |
| 172 | * length == PRIMES[primeIndex] */ |
| 173 | UBool allocated; /* Was this UHashtable allocated? */ |
| 174 | }; |
| 175 | typedef struct UHashtable UHashtable; |
| 176 | |
| 177 | U_CDECL_END |
| 178 | |
| 179 | /******************************************************************** |
| 180 | * API |
| 181 | ********************************************************************/ |
| 182 | |
| 183 | /** |
| 184 | * Initialize a new UHashtable. |
| 185 | * @param keyHash A pointer to the key hashing function. Must not be |
| 186 | * NULL. |
| 187 | * @param keyComp A pointer to the function that compares keys. Must |
| 188 | * not be NULL. |
| 189 | * @param status A pointer to an UErrorCode to receive any errors. |
| 190 | * @return A pointer to a UHashtable, or 0 if an error occurred. |
| 191 | * @see uhash_openSize |
| 192 | */ |
| 193 | U_CAPI UHashtable* U_EXPORT2 |
| 194 | uhash_open(UHashFunction *keyHash, |
| 195 | UKeyComparator *keyComp, |
| 196 | UValueComparator *valueComp, |
| 197 | UErrorCode *status); |
| 198 | |
| 199 | /** |
| 200 | * Initialize a new UHashtable with a given initial size. |
| 201 | * @param keyHash A pointer to the key hashing function. Must not be |
| 202 | * NULL. |
| 203 | * @param keyComp A pointer to the function that compares keys. Must |
| 204 | * not be NULL. |
| 205 | * @param size The initial capacity of this hash table. |
| 206 | * @param status A pointer to an UErrorCode to receive any errors. |
| 207 | * @return A pointer to a UHashtable, or 0 if an error occurred. |
| 208 | * @see uhash_open |
| 209 | */ |
| 210 | U_CAPI UHashtable* U_EXPORT2 |
| 211 | uhash_openSize(UHashFunction *keyHash, |
| 212 | UKeyComparator *keyComp, |
| 213 | UValueComparator *valueComp, |
| 214 | int32_t size, |
| 215 | UErrorCode *status); |
| 216 | |
| 217 | /** |
| 218 | * Initialize an existing UHashtable. |
| 219 | * @param keyHash A pointer to the key hashing function. Must not be |
| 220 | * NULL. |
| 221 | * @param keyComp A pointer to the function that compares keys. Must |
| 222 | * not be NULL. |
| 223 | * @param status A pointer to an UErrorCode to receive any errors. |
| 224 | * @return A pointer to a UHashtable, or 0 if an error occurred. |
| 225 | * @see uhash_openSize |
| 226 | */ |
| 227 | U_CAPI UHashtable* U_EXPORT2 |
| 228 | uhash_init(UHashtable *hash, |
| 229 | UHashFunction *keyHash, |
| 230 | UKeyComparator *keyComp, |
| 231 | UValueComparator *valueComp, |
| 232 | UErrorCode *status); |
| 233 | |
| 234 | /** |
| 235 | * Initialize an existing UHashtable. |
| 236 | * @param keyHash A pointer to the key hashing function. Must not be |
| 237 | * NULL. |
| 238 | * @param keyComp A pointer to the function that compares keys. Must |
| 239 | * not be NULL. |
| 240 | * @param size The initial capacity of this hash table. |
| 241 | * @param status A pointer to an UErrorCode to receive any errors. |
| 242 | * @return A pointer to a UHashtable, or 0 if an error occurred. |
| 243 | * @see uhash_openSize |
| 244 | */ |
| 245 | U_CAPI UHashtable* U_EXPORT2 |
| 246 | uhash_initSize(UHashtable *hash, |
| 247 | UHashFunction *keyHash, |
| 248 | UKeyComparator *keyComp, |
| 249 | UValueComparator *valueComp, |
| 250 | int32_t size, |
| 251 | UErrorCode *status); |
| 252 | |
| 253 | /** |
| 254 | * Close a UHashtable, releasing the memory used. |
| 255 | * @param hash The UHashtable to close. If hash is NULL no operation is performed. |
| 256 | */ |
| 257 | U_CAPI void U_EXPORT2 |
| 258 | uhash_close(UHashtable *hash); |
| 259 | |
| 260 | |
| 261 | |
| 262 | /** |
| 263 | * Set the function used to hash keys. |
| 264 | * @param hash The UHashtable to set |
| 265 | * @param fn the function to be used hash keys; must not be NULL |
| 266 | * @return the previous key hasher; non-NULL |
| 267 | */ |
| 268 | U_CAPI UHashFunction *U_EXPORT2 |
| 269 | uhash_setKeyHasher(UHashtable *hash, UHashFunction *fn); |
| 270 | |
| 271 | /** |
| 272 | * Set the function used to compare keys. The default comparison is a |
| 273 | * void* pointer comparison. |
| 274 | * @param hash The UHashtable to set |
| 275 | * @param fn the function to be used compare keys; must not be NULL |
| 276 | * @return the previous key comparator; non-NULL |
| 277 | */ |
| 278 | U_CAPI UKeyComparator *U_EXPORT2 |
| 279 | uhash_setKeyComparator(UHashtable *hash, UKeyComparator *fn); |
| 280 | |
| 281 | /** |
| 282 | * Set the function used to compare values. The default comparison is a |
| 283 | * void* pointer comparison. |
| 284 | * @param hash The UHashtable to set |
| 285 | * @param fn the function to be used compare keys; must not be NULL |
| 286 | * @return the previous key comparator; non-NULL |
| 287 | */ |
| 288 | U_CAPI UValueComparator *U_EXPORT2 |
| 289 | uhash_setValueComparator(UHashtable *hash, UValueComparator *fn); |
| 290 | |
| 291 | /** |
| 292 | * Set the function used to delete keys. If this function pointer is |
| 293 | * NULL, this hashtable does not delete keys. If it is non-NULL, this |
| 294 | * hashtable does delete keys. This function should be set once |
| 295 | * before any elements are added to the hashtable and should not be |
| 296 | * changed thereafter. |
| 297 | * @param hash The UHashtable to set |
| 298 | * @param fn the function to be used delete keys, or NULL |
| 299 | * @return the previous key deleter; may be NULL |
| 300 | */ |
| 301 | U_CAPI UObjectDeleter *U_EXPORT2 |
| 302 | uhash_setKeyDeleter(UHashtable *hash, UObjectDeleter *fn); |
| 303 | |
| 304 | /** |
| 305 | * Set the function used to delete values. If this function pointer |
| 306 | * is NULL, this hashtable does not delete values. If it is non-NULL, |
| 307 | * this hashtable does delete values. This function should be set |
| 308 | * once before any elements are added to the hashtable and should not |
| 309 | * be changed thereafter. |
| 310 | * @param hash The UHashtable to set |
| 311 | * @param fn the function to be used delete values, or NULL |
| 312 | * @return the previous value deleter; may be NULL |
| 313 | */ |
| 314 | U_CAPI UObjectDeleter *U_EXPORT2 |
| 315 | uhash_setValueDeleter(UHashtable *hash, UObjectDeleter *fn); |
| 316 | |
| 317 | /** |
| 318 | * Specify whether or not, and how, the hastable resizes itself. |
| 319 | * By default, tables grow but do not shrink (policy U_GROW). |
| 320 | * See enum UHashResizePolicy. |
| 321 | * @param hash The UHashtable to set |
| 322 | * @param policy The way the hashtable resizes itself, {U_GROW, U_GROW_AND_SHRINK, U_FIXED} |
| 323 | */ |
| 324 | U_CAPI void U_EXPORT2 |
| 325 | uhash_setResizePolicy(UHashtable *hash, enum UHashResizePolicy policy); |
| 326 | |
| 327 | /** |
| 328 | * Get the number of key-value pairs stored in a UHashtable. |
| 329 | * @param hash The UHashtable to query. |
| 330 | * @return The number of key-value pairs stored in hash. |
| 331 | */ |
| 332 | U_CAPI int32_t U_EXPORT2 |
| 333 | uhash_count(const UHashtable *hash); |
| 334 | |
| 335 | /** |
| 336 | * Put a (key=pointer, value=pointer) item in a UHashtable. If the |
| 337 | * keyDeleter is non-NULL, then the hashtable owns 'key' after this |
| 338 | * call. If the valueDeleter is non-NULL, then the hashtable owns |
| 339 | * 'value' after this call. Storing a NULL value is the same as |
| 340 | * calling uhash_remove(). |
| 341 | * @param hash The target UHashtable. |
| 342 | * @param key The key to store. |
| 343 | * @param value The value to store, may be NULL (see above). |
| 344 | * @param status A pointer to an UErrorCode to receive any errors. |
| 345 | * @return The previous value, or NULL if none. |
| 346 | * @see uhash_get |
| 347 | */ |
| 348 | U_CAPI void* U_EXPORT2 |
| 349 | uhash_put(UHashtable *hash, |
| 350 | void *key, |
| 351 | void *value, |
| 352 | UErrorCode *status); |
| 353 | |
| 354 | /** |
| 355 | * Put a (key=integer, value=pointer) item in a UHashtable. |
| 356 | * keyDeleter must be NULL. If the valueDeleter is non-NULL, then the |
| 357 | * hashtable owns 'value' after this call. Storing a NULL value is |
| 358 | * the same as calling uhash_remove(). |
| 359 | * @param hash The target UHashtable. |
| 360 | * @param key The integer key to store. |
| 361 | * @param value The value to store, may be NULL (see above). |
| 362 | * @param status A pointer to an UErrorCode to receive any errors. |
| 363 | * @return The previous value, or NULL if none. |
| 364 | * @see uhash_get |
| 365 | */ |
| 366 | U_CAPI void* U_EXPORT2 |
| 367 | uhash_iput(UHashtable *hash, |
| 368 | int32_t key, |
| 369 | void* value, |
| 370 | UErrorCode *status); |
| 371 | |
| 372 | /** |
| 373 | * Put a (key=pointer, value=integer) item in a UHashtable. If the |
| 374 | * keyDeleter is non-NULL, then the hashtable owns 'key' after this |
| 375 | * call. valueDeleter must be NULL. Storing a 0 value is the same as |
| 376 | * calling uhash_remove(). |
| 377 | * @param hash The target UHashtable. |
| 378 | * @param key The key to store. |
| 379 | * @param value The integer value to store. |
| 380 | * @param status A pointer to an UErrorCode to receive any errors. |
| 381 | * @return The previous value, or 0 if none. |
| 382 | * @see uhash_get |
| 383 | */ |
| 384 | U_CAPI int32_t U_EXPORT2 |
| 385 | uhash_puti(UHashtable *hash, |
| 386 | void* key, |
| 387 | int32_t value, |
| 388 | UErrorCode *status); |
| 389 | |
| 390 | /** |
| 391 | * Put a (key=integer, value=integer) item in a UHashtable. If the |
| 392 | * keyDeleter is non-NULL, then the hashtable owns 'key' after this |
| 393 | * call. valueDeleter must be NULL. Storing a 0 value is the same as |
| 394 | * calling uhash_remove(). |
| 395 | * @param hash The target UHashtable. |
| 396 | * @param key The key to store. |
| 397 | * @param value The integer value to store. |
| 398 | * @param status A pointer to an UErrorCode to receive any errors. |
| 399 | * @return The previous value, or 0 if none. |
| 400 | * @see uhash_get |
| 401 | */ |
| 402 | U_CAPI int32_t U_EXPORT2 |
| 403 | uhash_iputi(UHashtable *hash, |
| 404 | int32_t key, |
| 405 | int32_t value, |
| 406 | UErrorCode *status); |
| 407 | |
| 408 | /** |
| 409 | * Retrieve a pointer value from a UHashtable using a pointer key, |
| 410 | * as previously stored by uhash_put(). |
| 411 | * @param hash The target UHashtable. |
| 412 | * @param key A pointer key stored in a hashtable |
| 413 | * @return The requested item, or NULL if not found. |
| 414 | */ |
| 415 | U_CAPI void* U_EXPORT2 |
| 416 | uhash_get(const UHashtable *hash, |
| 417 | const void *key); |
| 418 | |
| 419 | /** |
| 420 | * Retrieve a pointer value from a UHashtable using a integer key, |
| 421 | * as previously stored by uhash_iput(). |
| 422 | * @param hash The target UHashtable. |
| 423 | * @param key An integer key stored in a hashtable |
| 424 | * @return The requested item, or NULL if not found. |
| 425 | */ |
| 426 | U_CAPI void* U_EXPORT2 |
| 427 | uhash_iget(const UHashtable *hash, |
| 428 | int32_t key); |
| 429 | |
| 430 | /** |
| 431 | * Retrieve an integer value from a UHashtable using a pointer key, |
| 432 | * as previously stored by uhash_puti(). |
| 433 | * @param hash The target UHashtable. |
| 434 | * @param key A pointer key stored in a hashtable |
| 435 | * @return The requested item, or 0 if not found. |
| 436 | */ |
| 437 | U_CAPI int32_t U_EXPORT2 |
| 438 | uhash_geti(const UHashtable *hash, |
| 439 | const void* key); |
| 440 | /** |
| 441 | * Retrieve an integer value from a UHashtable using an integer key, |
| 442 | * as previously stored by uhash_iputi(). |
| 443 | * @param hash The target UHashtable. |
| 444 | * @param key An integer key stored in a hashtable |
| 445 | * @return The requested item, or 0 if not found. |
| 446 | */ |
| 447 | U_CAPI int32_t U_EXPORT2 |
| 448 | uhash_igeti(const UHashtable *hash, |
| 449 | int32_t key); |
| 450 | |
| 451 | /** |
| 452 | * Remove an item from a UHashtable stored by uhash_put(). |
| 453 | * @param hash The target UHashtable. |
| 454 | * @param key A key stored in a hashtable |
| 455 | * @return The item removed, or NULL if not found. |
| 456 | */ |
| 457 | U_CAPI void* U_EXPORT2 |
| 458 | uhash_remove(UHashtable *hash, |
| 459 | const void *key); |
| 460 | |
| 461 | /** |
| 462 | * Remove an item from a UHashtable stored by uhash_iput(). |
| 463 | * @param hash The target UHashtable. |
| 464 | * @param key An integer key stored in a hashtable |
| 465 | * @return The item removed, or NULL if not found. |
| 466 | */ |
| 467 | U_CAPI void* U_EXPORT2 |
| 468 | uhash_iremove(UHashtable *hash, |
| 469 | int32_t key); |
| 470 | |
| 471 | /** |
| 472 | * Remove an item from a UHashtable stored by uhash_puti(). |
| 473 | * @param hash The target UHashtable. |
| 474 | * @param key An key stored in a hashtable |
| 475 | * @return The item removed, or 0 if not found. |
| 476 | */ |
| 477 | U_CAPI int32_t U_EXPORT2 |
| 478 | uhash_removei(UHashtable *hash, |
| 479 | const void* key); |
| 480 | |
| 481 | /** |
| 482 | * Remove an item from a UHashtable stored by uhash_iputi(). |
| 483 | * @param hash The target UHashtable. |
| 484 | * @param key An integer key stored in a hashtable |
| 485 | * @return The item removed, or 0 if not found. |
| 486 | */ |
| 487 | U_CAPI int32_t U_EXPORT2 |
| 488 | uhash_iremovei(UHashtable *hash, |
| 489 | int32_t key); |
| 490 | |
| 491 | /** |
| 492 | * Remove all items from a UHashtable. |
| 493 | * @param hash The target UHashtable. |
| 494 | */ |
| 495 | U_CAPI void U_EXPORT2 |
| 496 | uhash_removeAll(UHashtable *hash); |
| 497 | |
| 498 | /** |
| 499 | * Locate an element of a UHashtable. The caller must not modify the |
| 500 | * returned object. The primary use of this function is to obtain the |
| 501 | * stored key when it may not be identical to the search key. For |
| 502 | * example, if the compare function is a case-insensitive string |
| 503 | * compare, then the hash key may be desired in order to obtain the |
| 504 | * canonical case corresponding to a search key. |
| 505 | * @param hash The target UHashtable. |
| 506 | * @param key A key stored in a hashtable |
| 507 | * @return a hash element, or NULL if the key is not found. |
| 508 | */ |
| 509 | U_CAPI const UHashElement* U_EXPORT2 |
| 510 | uhash_find(const UHashtable *hash, const void* key); |
| 511 | |
| 512 | /** |
| 513 | * \def UHASH_FIRST |
| 514 | * Constant for use with uhash_nextElement |
| 515 | * @see uhash_nextElement |
| 516 | */ |
| 517 | #define UHASH_FIRST (-1) |
| 518 | |
| 519 | /** |
| 520 | * Iterate through the elements of a UHashtable. The caller must not |
| 521 | * modify the returned object. However, uhash_removeElement() may be |
| 522 | * called during iteration to remove an element from the table. |
| 523 | * Iteration may safely be resumed afterwards. If uhash_put() is |
| 524 | * called during iteration the iteration will then be out of sync and |
| 525 | * should be restarted. |
| 526 | * @param hash The target UHashtable. |
| 527 | * @param pos This should be set to UHASH_FIRST initially, and left untouched |
| 528 | * thereafter. |
| 529 | * @return a hash element, or NULL if no further key-value pairs |
| 530 | * exist in the table. |
| 531 | */ |
| 532 | U_CAPI const UHashElement* U_EXPORT2 |
| 533 | uhash_nextElement(const UHashtable *hash, |
| 534 | int32_t *pos); |
| 535 | |
| 536 | /** |
| 537 | * Remove an element, returned by uhash_nextElement(), from the table. |
| 538 | * Iteration may be safely continued afterwards. |
| 539 | * @param hash The hashtable |
| 540 | * @param e The element, returned by uhash_nextElement(), to remove. |
| 541 | * Must not be NULL. Must not be an empty or deleted element (as long |
| 542 | * as this was returned by uhash_nextElement() it will not be empty or |
| 543 | * deleted). Note: Although this parameter is const, it will be |
| 544 | * modified. |
| 545 | * @return the value that was removed. |
| 546 | */ |
| 547 | U_CAPI void* U_EXPORT2 |
| 548 | uhash_removeElement(UHashtable *hash, const UHashElement* e); |
| 549 | |
| 550 | /******************************************************************** |
| 551 | * UHashTok convenience |
| 552 | ********************************************************************/ |
| 553 | |
| 554 | /** |
| 555 | * Return a UHashTok for an integer. |
| 556 | * @param i The given integer |
| 557 | * @return a UHashTok for an integer. |
| 558 | */ |
| 559 | /*U_CAPI UHashTok U_EXPORT2 |
| 560 | uhash_toki(int32_t i);*/ |
| 561 | |
| 562 | /** |
| 563 | * Return a UHashTok for a pointer. |
| 564 | * @param p The given pointer |
| 565 | * @return a UHashTok for a pointer. |
| 566 | */ |
| 567 | /*U_CAPI UHashTok U_EXPORT2 |
| 568 | uhash_tokp(void* p);*/ |
| 569 | |
| 570 | /******************************************************************** |
| 571 | * UChar* and char* Support Functions |
| 572 | ********************************************************************/ |
| 573 | |
| 574 | /** |
| 575 | * Generate a hash code for a null-terminated UChar* string. If the |
| 576 | * string is not null-terminated do not use this function. Use |
| 577 | * together with uhash_compareUChars. |
| 578 | * @param key The string (const UChar*) to hash. |
| 579 | * @return A hash code for the key. |
| 580 | */ |
| 581 | U_CAPI int32_t U_EXPORT2 |
| 582 | uhash_hashUChars(const UHashTok key); |
| 583 | |
| 584 | /** |
| 585 | * Generate a hash code for a null-terminated char* string. If the |
| 586 | * string is not null-terminated do not use this function. Use |
| 587 | * together with uhash_compareChars. |
| 588 | * @param key The string (const char*) to hash. |
| 589 | * @return A hash code for the key. |
| 590 | */ |
| 591 | U_CAPI int32_t U_EXPORT2 |
| 592 | uhash_hashChars(const UHashTok key); |
| 593 | |
| 594 | /** |
| 595 | * Generate a case-insensitive hash code for a null-terminated char* |
| 596 | * string. If the string is not null-terminated do not use this |
| 597 | * function. Use together with uhash_compareIChars. |
| 598 | * @param key The string (const char*) to hash. |
| 599 | * @return A hash code for the key. |
| 600 | */ |
| 601 | U_CAPI int32_t U_EXPORT2 |
| 602 | uhash_hashIChars(const UHashTok key); |
| 603 | |
| 604 | /** |
| 605 | * Comparator for null-terminated UChar* strings. Use together with |
| 606 | * uhash_hashUChars. |
| 607 | * @param key1 The string for comparison |
| 608 | * @param key2 The string for comparison |
| 609 | * @return true if key1 and key2 are equal, return false otherwise. |
| 610 | */ |
| 611 | U_CAPI UBool U_EXPORT2 |
| 612 | uhash_compareUChars(const UHashTok key1, const UHashTok key2); |
| 613 | |
| 614 | /** |
| 615 | * Comparator for null-terminated char* strings. Use together with |
| 616 | * uhash_hashChars. |
| 617 | * @param key1 The string for comparison |
| 618 | * @param key2 The string for comparison |
| 619 | * @return true if key1 and key2 are equal, return false otherwise. |
| 620 | */ |
| 621 | U_CAPI UBool U_EXPORT2 |
| 622 | uhash_compareChars(const UHashTok key1, const UHashTok key2); |
| 623 | |
| 624 | /** |
| 625 | * Case-insensitive comparator for null-terminated char* strings. Use |
| 626 | * together with uhash_hashIChars. |
| 627 | * @param key1 The string for comparison |
| 628 | * @param key2 The string for comparison |
| 629 | * @return true if key1 and key2 are equal, return false otherwise. |
| 630 | */ |
| 631 | U_CAPI UBool U_EXPORT2 |
| 632 | uhash_compareIChars(const UHashTok key1, const UHashTok key2); |
| 633 | |
| 634 | /******************************************************************** |
| 635 | * UnicodeString Support Functions |
| 636 | ********************************************************************/ |
| 637 | |
| 638 | /** |
| 639 | * Hash function for UnicodeString* keys. |
| 640 | * @param key The string (const char*) to hash. |
| 641 | * @return A hash code for the key. |
| 642 | */ |
| 643 | U_CAPI int32_t U_EXPORT2 |
| 644 | uhash_hashUnicodeString(const UElement key); |
| 645 | |
| 646 | /** |
| 647 | * Hash function for UnicodeString* keys (case insensitive). |
| 648 | * Make sure to use together with uhash_compareCaselessUnicodeString. |
| 649 | * @param key The string (const char*) to hash. |
| 650 | * @return A hash code for the key. |
| 651 | */ |
| 652 | U_CAPI int32_t U_EXPORT2 |
| 653 | uhash_hashCaselessUnicodeString(const UElement key); |
| 654 | |
| 655 | /******************************************************************** |
| 656 | * int32_t Support Functions |
| 657 | ********************************************************************/ |
| 658 | |
| 659 | /** |
| 660 | * Hash function for 32-bit integer keys. |
| 661 | * @param key The string (const char*) to hash. |
| 662 | * @return A hash code for the key. |
| 663 | */ |
| 664 | U_CAPI int32_t U_EXPORT2 |
| 665 | uhash_hashLong(const UHashTok key); |
| 666 | |
| 667 | /** |
| 668 | * Comparator function for 32-bit integer keys. |
| 669 | * @param key1 The integer for comparison |
| 670 | * @param Key2 The integer for comparison |
| 671 | * @return true if key1 and key2 are equal, return false otherwise |
| 672 | */ |
| 673 | U_CAPI UBool U_EXPORT2 |
| 674 | uhash_compareLong(const UHashTok key1, const UHashTok key2); |
| 675 | |
| 676 | /******************************************************************** |
| 677 | * Other Support Functions |
| 678 | ********************************************************************/ |
| 679 | |
| 680 | /** |
| 681 | * Deleter for Hashtable objects. |
| 682 | * @param obj The object to be deleted |
| 683 | */ |
| 684 | U_CAPI void U_EXPORT2 |
| 685 | uhash_deleteHashtable(void *obj); |
| 686 | |
| 687 | /* Use uprv_free() itself as a deleter for any key or value allocated using uprv_malloc. */ |
| 688 | |
| 689 | /** |
| 690 | * Checks if the given hash tables are equal or not. |
| 691 | * @param hash1 |
| 692 | * @param hash2 |
| 693 | * @return true if the hashtables are equal and false if not. |
| 694 | */ |
| 695 | U_CAPI UBool U_EXPORT2 |
| 696 | uhash_equals(const UHashtable* hash1, const UHashtable* hash2); |
| 697 | |
| 698 | |
| 699 | #if U_SHOW_CPLUSPLUS_API |
| 700 | |
| 701 | U_NAMESPACE_BEGIN |
| 702 | |
| 703 | /** |
| 704 | * \class LocalUHashtablePointer |
| 705 | * "Smart pointer" class, closes a UHashtable via uhash_close(). |
| 706 | * For most methods see the LocalPointerBase base class. |
| 707 | * |
| 708 | * @see LocalPointerBase |
| 709 | * @see LocalPointer |
| 710 | * @stable ICU 4.4 |
| 711 | */ |
| 712 | U_DEFINE_LOCAL_OPEN_POINTER(LocalUHashtablePointer, UHashtable, uhash_close); |
| 713 | |
| 714 | U_NAMESPACE_END |
| 715 | |
| 716 | #endif |
| 717 | |
| 718 | #endif |