1 /* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef APR_TABLES_H 18 #define APR_TABLES_H 19 20 /** 21 * @file apr_tables.h 22 * @brief APR Table library 23 */ 24 25 #include "apr.h" 26 #include "apr_pools.h" 27 28 #if APR_HAVE_STDARG_H 29 #include <stdarg.h> /* for va_list */ 30 #endif 31 32 #ifdef __cplusplus 33 extern "C" { 34 #endif /* __cplusplus */ 35 36 /** 37 * @defgroup apr_tables Table and Array Functions 38 * @ingroup APR 39 * Arrays are used to store data which is referenced sequentially or 40 * as a stack. Functions are provided to push and pop individual 41 * elements as well as to operate on the entire array. 42 * 43 * Tables are used to store data which can be referenced by key. 44 * Limited capabilities are provided for tables with multiple elements 45 * which share a key; while key lookup will return only a single 46 * element, iteration is available. Additionally, a table can be 47 * compressed to resolve duplicates. 48 * 49 * Both arrays and tables may store string or binary data; some features, 50 * such as concatenation or merging of elements, work only for string 51 * data. 52 * @{ 53 */ 54 55 /** the table abstract data type */ 56 typedef struct apr_table_t apr_table_t; 57 58 /** @see apr_array_header_t */ 59 typedef struct apr_array_header_t apr_array_header_t; 60 61 /** An opaque array type */ 62 struct apr_array_header_t { 63 /** The pool the array is allocated out of */ 64 apr_pool_t *pool; 65 /** The amount of memory allocated for each element of the array */ 66 int elt_size; 67 /** The number of active elements in the array */ 68 int nelts; 69 /** The number of elements allocated in the array */ 70 int nalloc; 71 /** The elements in the array */ 72 char *elts; 73 }; 74 75 /** 76 * The (opaque) structure for string-content tables. 77 */ 78 typedef struct apr_table_entry_t apr_table_entry_t; 79 80 /** The type for each entry in a string-content table */ 81 struct apr_table_entry_t { 82 /** The key for the current table entry */ 83 char *key; /* maybe NULL in future; 84 * check when iterating thru table_elts 85 */ 86 /** The value for the current table entry */ 87 char *val; 88 89 /** A checksum for the key, for use by the apr_table internals */ 90 apr_uint32_t key_checksum; 91 }; 92 93 /** 94 * Get the elements from a table. 95 * @param t The table 96 * @return An array containing the contents of the table 97 */ 98 APR_DECLARE(const apr_array_header_t *) apr_table_elts(const apr_table_t *t); 99 100 /** 101 * Determine if the table is empty (either NULL or having no elements). 102 * @param t The table to check 103 * @return True if empty, False otherwise 104 */ 105 APR_DECLARE(int) apr_is_empty_table(const apr_table_t *t); 106 107 /** 108 * Determine if the array is empty (either NULL or having no elements). 109 * @param a The array to check 110 * @return True if empty, False otherwise 111 */ 112 APR_DECLARE(int) apr_is_empty_array(const apr_array_header_t *a); 113 114 /** 115 * Create an array. 116 * @param p The pool to allocate the memory out of 117 * @param nelts the number of elements in the initial array 118 * @param elt_size The size of each element in the array. 119 * @return The new array 120 */ 121 APR_DECLARE(apr_array_header_t *) apr_array_make(apr_pool_t *p, 122 int nelts, int elt_size); 123 124 /** 125 * Add a new element to an array (as a first-in, last-out stack). 126 * @param arr The array to add an element to. 127 * @return Location for the new element in the array. 128 * @remark If there are no free spots in the array, then this function will 129 * allocate new space for the new element. 130 */ 131 APR_DECLARE(void *) apr_array_push(apr_array_header_t *arr); 132 133 /** A helper macro for accessing a member of an APR array. 134 * 135 * @param ary the array 136 * @param i the index into the array to return 137 * @param type the type of the objects stored in the array 138 * 139 * @return the item at index i 140 */ 141 #define APR_ARRAY_IDX(ary,i,type) (((type *)(ary)->elts)[i]) 142 143 /** A helper macro for pushing elements into an APR array. 144 * 145 * @param ary the array 146 * @param type the type of the objects stored in the array 147 * 148 * @return the location where the new object should be placed 149 */ 150 #define APR_ARRAY_PUSH(ary,type) (*((type *)apr_array_push(ary))) 151 152 /** 153 * Remove an element from an array (as a first-in, last-out stack). 154 * @param arr The array to remove an element from. 155 * @return Location of the element in the array. 156 * @remark If there are no elements in the array, NULL is returned. 157 */ 158 APR_DECLARE(void *) apr_array_pop(apr_array_header_t *arr); 159 160 /** 161 * Remove all elements from an array. 162 * @param arr The array to remove all elements from. 163 * @remark As the underlying storage is allocated from a pool, no 164 * memory is freed by this operation, but is available for reuse. 165 */ 166 APR_DECLARE(void) apr_array_clear(apr_array_header_t *arr); 167 168 /** 169 * Concatenate two arrays together. 170 * @param dst The destination array, and the one to go first in the combined 171 * array 172 * @param src The source array to add to the destination array 173 */ 174 APR_DECLARE(void) apr_array_cat(apr_array_header_t *dst, 175 const apr_array_header_t *src); 176 177 /** 178 * Copy the entire array. 179 * @param p The pool to allocate the copy of the array out of 180 * @param arr The array to copy 181 * @return An exact copy of the array passed in 182 * @remark The alternate apr_array_copy_hdr copies only the header, and arranges 183 * for the elements to be copied if (and only if) the code subsequently 184 * does a push or arraycat. 185 */ 186 APR_DECLARE(apr_array_header_t *) apr_array_copy(apr_pool_t *p, 187 const apr_array_header_t *arr); 188 /** 189 * Copy the headers of the array, and arrange for the elements to be copied if 190 * and only if the code subsequently does a push or arraycat. 191 * @param p The pool to allocate the copy of the array out of 192 * @param arr The array to copy 193 * @return An exact copy of the array passed in 194 * @remark The alternate apr_array_copy copies the *entire* array. 195 */ 196 APR_DECLARE(apr_array_header_t *) apr_array_copy_hdr(apr_pool_t *p, 197 const apr_array_header_t *arr); 198 199 /** 200 * Append one array to the end of another, creating a new array in the process. 201 * @param p The pool to allocate the new array out of 202 * @param first The array to put first in the new array. 203 * @param second The array to put second in the new array. 204 * @return A new array containing the data from the two arrays passed in. 205 */ 206 APR_DECLARE(apr_array_header_t *) apr_array_append(apr_pool_t *p, 207 const apr_array_header_t *first, 208 const apr_array_header_t *second); 209 210 /** 211 * Generate a new string from the apr_pool_t containing the concatenated 212 * sequence of substrings referenced as elements within the array. The string 213 * will be empty if all substrings are empty or null, or if there are no 214 * elements in the array. If sep is non-NUL, it will be inserted between 215 * elements as a separator. 216 * @param p The pool to allocate the string out of 217 * @param arr The array to generate the string from 218 * @param sep The separator to use 219 * @return A string containing all of the data in the array. 220 */ 221 APR_DECLARE(char *) apr_array_pstrcat(apr_pool_t *p, 222 const apr_array_header_t *arr, 223 const char sep); 224 225 /** 226 * Make a new table. 227 * @param p The pool to allocate the pool out of 228 * @param nelts The number of elements in the initial table. 229 * @return The new table. 230 * @warning This table can only store text data 231 */ 232 APR_DECLARE(apr_table_t *) apr_table_make(apr_pool_t *p, int nelts); 233 234 /** 235 * Create a new table and copy another table into it. 236 * @param p The pool to allocate the new table out of 237 * @param t The table to copy 238 * @return A copy of the table passed in 239 * @warning The table keys and respective values are not copied 240 */ 241 APR_DECLARE(apr_table_t *) apr_table_copy(apr_pool_t *p, 242 const apr_table_t *t); 243 244 /** 245 * Create a new table whose contents are deep copied from the given 246 * table. A deep copy operation copies all fields, and makes copies 247 * of dynamically allocated memory pointed to by the fields. 248 * @param p The pool to allocate the new table out of 249 * @param t The table to clone 250 * @return A deep copy of the table passed in 251 */ 252 APR_DECLARE(apr_table_t *) apr_table_clone(apr_pool_t *p, 253 const apr_table_t *t); 254 255 /** 256 * Delete all of the elements from a table. 257 * @param t The table to clear 258 */ 259 APR_DECLARE(void) apr_table_clear(apr_table_t *t); 260 261 /** 262 * Get the value associated with a given key from the table. After this call, 263 * the data is still in the table. 264 * @param t The table to search for the key 265 * @param key The key to search for (case does not matter) 266 * @return The value associated with the key, or NULL if the key does not exist. 267 */ 268 APR_DECLARE(const char *) apr_table_get(const apr_table_t *t, const char *key); 269 270 /** 271 * Get values associated with a given key from the table. If more than one 272 * value exists, return a comma separated list of values. After this call, the 273 * data is still in the table. 274 * @param p The pool to allocate the combined value from, if necessary 275 * @param t The table to search for the key 276 * @param key The key to search for (case does not matter) 277 * @return The value associated with the key, or NULL if the key does not exist. 278 */ 279 APR_DECLARE(const char *) apr_table_getm(apr_pool_t *p, const apr_table_t *t, 280 const char *key); 281 282 /** 283 * Add a key/value pair to a table. If another element already exists with the 284 * same key, this will overwrite the old data. 285 * @param t The table to add the data to. 286 * @param key The key to use (case does not matter) 287 * @param val The value to add 288 * @remark When adding data, this function makes a copy of both the key and the 289 * value. 290 */ 291 APR_DECLARE(void) apr_table_set(apr_table_t *t, const char *key, 292 const char *val); 293 294 /** 295 * Add a key/value pair to a table. If another element already exists with the 296 * same key, this will overwrite the old data. 297 * @param t The table to add the data to. 298 * @param key The key to use (case does not matter) 299 * @param val The value to add 300 * @warning When adding data, this function does not make a copy of the key or 301 * the value, so care should be taken to ensure that the values will 302 * not change after they have been added.. 303 */ 304 APR_DECLARE(void) apr_table_setn(apr_table_t *t, const char *key, 305 const char *val); 306 307 /** 308 * Remove data from the table. 309 * @param t The table to remove data from 310 * @param key The key of the data being removed (case does not matter) 311 */ 312 APR_DECLARE(void) apr_table_unset(apr_table_t *t, const char *key); 313 314 /** 315 * Add data to a table by merging the value with data that has already been 316 * stored. The merging is done by concatenating the two values, separated 317 * by the string ", ". 318 * @param t The table to search for the data 319 * @param key The key to merge data for (case does not matter) 320 * @param val The data to add 321 * @remark If the key is not found, then this function acts like apr_table_add 322 */ 323 APR_DECLARE(void) apr_table_merge(apr_table_t *t, const char *key, 324 const char *val); 325 326 /** 327 * Add data to a table by merging the value with data that has already been 328 * stored. The merging is done by concatenating the two values, separated 329 * by the string ", ". 330 * @param t The table to search for the data 331 * @param key The key to merge data for (case does not matter) 332 * @param val The data to add 333 * @remark If the key is not found, then this function acts like apr_table_addn 334 */ 335 APR_DECLARE(void) apr_table_mergen(apr_table_t *t, const char *key, 336 const char *val); 337 338 /** 339 * Add data to a table, regardless of whether there is another element with the 340 * same key. 341 * @param t The table to add to 342 * @param key The key to use 343 * @param val The value to add. 344 * @remark When adding data, this function makes a copy of both the key and the 345 * value. 346 */ 347 APR_DECLARE(void) apr_table_add(apr_table_t *t, const char *key, 348 const char *val); 349 350 /** 351 * Add data to a table, regardless of whether there is another element with the 352 * same key. 353 * @param t The table to add to 354 * @param key The key to use 355 * @param val The value to add. 356 * @remark When adding data, this function does not make a copy of the key or the 357 * value, so care should be taken to ensure that the values will not 358 * change after they have been added. 359 */ 360 APR_DECLARE(void) apr_table_addn(apr_table_t *t, const char *key, 361 const char *val); 362 363 /** 364 * Merge two tables into one new table. 365 * @param p The pool to use for the new table 366 * @param overlay The first table to put in the new table 367 * @param base The table to add at the end of the new table 368 * @return A new table containing all of the data from the two passed in 369 */ 370 APR_DECLARE(apr_table_t *) apr_table_overlay(apr_pool_t *p, 371 const apr_table_t *overlay, 372 const apr_table_t *base); 373 374 /** 375 * Declaration prototype for the iterator callback function of apr_table_do() 376 * and apr_table_vdo(). 377 * @param rec The data passed as the first argument to apr_table_[v]do() 378 * @param key The key from this iteration of the table 379 * @param value The value from this iteration of the table 380 * @remark Iteration continues while this callback function returns non-zero. 381 * To export the callback function for apr_table_[v]do() it must be declared 382 * in the _NONSTD convention. 383 */ 384 typedef int (apr_table_do_callback_fn_t)(void *rec, const char *key, 385 const char *value); 386 387 /** 388 * Iterate over a table running the provided function once for every 389 * element in the table. The varargs array must be a list of zero or 390 * more (char *) keys followed by a NULL pointer. If zero keys are 391 * given, the @param comp function will be invoked for every element 392 * in the table. Otherwise, the function is invoked only for those 393 * elements matching the keys specified. 394 * 395 * If an invocation of the @param comp function returns zero, 396 * iteration will continue using the next specified key, if any. 397 * 398 * @param comp The function to run 399 * @param rec The data to pass as the first argument to the function 400 * @param t The table to iterate over 401 * @param ... A varargs array of zero or more (char *) keys followed by NULL 402 * @return FALSE if one of the comp() iterations returned zero; TRUE if all 403 * iterations returned non-zero 404 * @see apr_table_do_callback_fn_t 405 */ 406 APR_DECLARE_NONSTD(int) apr_table_do(apr_table_do_callback_fn_t *comp, 407 void *rec, const apr_table_t *t, ...) 408 #if defined(__GNUC__) && __GNUC__ >= 4 409 __attribute__((sentinel)) 410 #endif 411 ; 412 413 /** 414 * Iterate over a table running the provided function once for every 415 * element in the table. The @param vp varargs parameter must be a 416 * list of zero or more (char *) keys followed by a NULL pointer. If 417 * zero keys are given, the @param comp function will be invoked for 418 * every element in the table. Otherwise, the function is invoked 419 * only for those elements matching the keys specified. 420 * 421 * If an invocation of the @param comp function returns zero, 422 * iteration will continue using the next specified key, if any. 423 * 424 * @param comp The function to run 425 * @param rec The data to pass as the first argument to the function 426 * @param t The table to iterate over 427 * @param vp List of zero or more (char *) keys followed by NULL 428 * @return FALSE if one of the comp() iterations returned zero; TRUE if all 429 * iterations returned non-zero 430 * @see apr_table_do_callback_fn_t 431 */ 432 APR_DECLARE(int) apr_table_vdo(apr_table_do_callback_fn_t *comp, 433 void *rec, const apr_table_t *t, va_list vp); 434 435 /** flag for overlap to use apr_table_setn */ 436 #define APR_OVERLAP_TABLES_SET (0) 437 /** flag for overlap to use apr_table_mergen */ 438 #define APR_OVERLAP_TABLES_MERGE (1) 439 /** 440 * For each element in table b, either use setn or mergen to add the data 441 * to table a. Which method is used is determined by the flags passed in. 442 * @param a The table to add the data to. 443 * @param b The table to iterate over, adding its data to table a 444 * @param flags How to add the table to table a. One of: 445 * APR_OVERLAP_TABLES_SET Use apr_table_setn 446 * APR_OVERLAP_TABLES_MERGE Use apr_table_mergen 447 * @remark When merging duplicates, the two values are concatenated, 448 * separated by the string ", ". 449 * @remark This function is highly optimized, and uses less memory and CPU cycles 450 * than a function that just loops through table b calling other functions. 451 */ 452 /** 453 * Conceptually, apr_table_overlap does this: 454 * 455 * <pre> 456 * apr_array_header_t *barr = apr_table_elts(b); 457 * apr_table_entry_t *belt = (apr_table_entry_t *)barr->elts; 458 * int i; 459 * 460 * for (i = 0; i < barr->nelts; ++i) { 461 * if (flags & APR_OVERLAP_TABLES_MERGE) { 462 * apr_table_mergen(a, belt[i].key, belt[i].val); 463 * } 464 * else { 465 * apr_table_setn(a, belt[i].key, belt[i].val); 466 * } 467 * } 468 * </pre> 469 * 470 * Except that it is more efficient (less space and cpu-time) especially 471 * when b has many elements. 472 * 473 * Notice the assumptions on the keys and values in b -- they must be 474 * in an ancestor of a's pool. In practice b and a are usually from 475 * the same pool. 476 */ 477 478 APR_DECLARE(void) apr_table_overlap(apr_table_t *a, const apr_table_t *b, 479 unsigned flags); 480 481 /** 482 * Eliminate redundant entries in a table by either overwriting 483 * or merging duplicates. 484 * 485 * @param t Table. 486 * @param flags APR_OVERLAP_TABLES_MERGE to merge, or 487 * APR_OVERLAP_TABLES_SET to overwrite 488 * @remark When merging duplicates, the two values are concatenated, 489 * separated by the string ", ". 490 */ 491 APR_DECLARE(void) apr_table_compress(apr_table_t *t, unsigned flags); 492 493 /** @} */ 494 495 #ifdef __cplusplus 496 } 497 #endif 498 499 #endif /* ! APR_TABLES_H */ 500