apr_tables.h revision 266735
1290001Sglebius/* Licensed to the Apache Software Foundation (ASF) under one or more 2290001Sglebius * contributor license agreements. See the NOTICE file distributed with 3290001Sglebius * this work for additional information regarding copyright ownership. 4290001Sglebius * The ASF licenses this file to You under the Apache License, Version 2.0 5290001Sglebius * (the "License"); you may not use this file except in compliance with 6290001Sglebius * the License. You may obtain a copy of the License at 7290001Sglebius * 8290001Sglebius * http://www.apache.org/licenses/LICENSE-2.0 9290001Sglebius * 10290001Sglebius * Unless required by applicable law or agreed to in writing, software 11290001Sglebius * distributed under the License is distributed on an "AS IS" BASIS, 12290001Sglebius * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13290001Sglebius * See the License for the specific language governing permissions and 14290001Sglebius * limitations under the License. 15290001Sglebius */ 16290001Sglebius 17290001Sglebius#ifndef APR_TABLES_H 18290001Sglebius#define APR_TABLES_H 19290001Sglebius 20290001Sglebius/** 21290001Sglebius * @file apr_tables.h 22290001Sglebius * @brief APR Table library 23290001Sglebius */ 24290001Sglebius 25290001Sglebius#include "apr.h" 26290001Sglebius#include "apr_pools.h" 27290001Sglebius 28290001Sglebius#if APR_HAVE_STDARG_H 29290001Sglebius#include <stdarg.h> /* for va_list */ 30290001Sglebius#endif 31290001Sglebius 32290001Sglebius#ifdef __cplusplus 33290001Sglebiusextern "C" { 34290001Sglebius#endif /* __cplusplus */ 35290001Sglebius 36290001Sglebius/** 37290001Sglebius * @defgroup apr_tables Table and Array Functions 38290001Sglebius * @ingroup APR 39290001Sglebius * Arrays are used to store data which is referenced sequentially or 40290001Sglebius * as a stack. Functions are provided to push and pop individual 41290001Sglebius * elements as well as to operate on the entire array. 42290001Sglebius * 43290001Sglebius * Tables are used to store data which can be referenced by key. 44290001Sglebius * Limited capabilities are provided for tables with multiple elements 45290001Sglebius * which share a key; while key lookup will return only a single 46290001Sglebius * element, iteration is available. Additionally, a table can be 47290001Sglebius * compressed to resolve duplicates. 48290001Sglebius * 49290001Sglebius * Both arrays and tables may store string or binary data; some features, 50290001Sglebius * such as concatenation or merging of elements, work only for string 51290001Sglebius * data. 52290001Sglebius * @{ 53290001Sglebius */ 54290001Sglebius 55290001Sglebius/** the table abstract data type */ 56290001Sglebiustypedef struct apr_table_t apr_table_t; 57290001Sglebius 58290001Sglebius/** @see apr_array_header_t */ 59290001Sglebiustypedef struct apr_array_header_t apr_array_header_t; 60290001Sglebius 61290001Sglebius/** An opaque array type */ 62290001Sglebiusstruct apr_array_header_t { 63290001Sglebius /** The pool the array is allocated out of */ 64290001Sglebius apr_pool_t *pool; 65290001Sglebius /** The amount of memory allocated for each element of the array */ 66290001Sglebius int elt_size; 67290001Sglebius /** The number of active elements in the array */ 68290001Sglebius int nelts; 69290001Sglebius /** The number of elements allocated in the array */ 70290001Sglebius int nalloc; 71290001Sglebius /** The elements in the array */ 72290001Sglebius char *elts; 73290001Sglebius}; 74290001Sglebius 75290001Sglebius/** 76290001Sglebius * The (opaque) structure for string-content tables. 77290001Sglebius */ 78290001Sglebiustypedef struct apr_table_entry_t apr_table_entry_t; 79290001Sglebius 80290001Sglebius/** The type for each entry in a string-content table */ 81290001Sglebiusstruct apr_table_entry_t { 82290001Sglebius /** The key for the current table entry */ 83290001Sglebius char *key; /* maybe NULL in future; 84290001Sglebius * check when iterating thru table_elts 85290001Sglebius */ 86290001Sglebius /** The value for the current table entry */ 87290001Sglebius char *val; 88290001Sglebius 89290001Sglebius /** A checksum for the key, for use by the apr_table internals */ 90290001Sglebius apr_uint32_t key_checksum; 91290001Sglebius}; 92290001Sglebius 93290001Sglebius/** 94290001Sglebius * Get the elements from a table. 95290001Sglebius * @param t The table 96290001Sglebius * @return An array containing the contents of the table 97290001Sglebius */ 98290001SglebiusAPR_DECLARE(const apr_array_header_t *) apr_table_elts(const apr_table_t *t); 99290001Sglebius 100290001Sglebius/** 101290001Sglebius * Determine if the table is empty (either NULL or having no elements). 102290001Sglebius * @param t The table to check 103290001Sglebius * @return True if empty, False otherwise 104290001Sglebius */ 105290001SglebiusAPR_DECLARE(int) apr_is_empty_table(const apr_table_t *t); 106290001Sglebius 107290001Sglebius/** 108290001Sglebius * Determine if the array is empty (either NULL or having no elements). 109290001Sglebius * @param a The array to check 110290001Sglebius * @return True if empty, False otherwise 111290001Sglebius */ 112290001SglebiusAPR_DECLARE(int) apr_is_empty_array(const apr_array_header_t *a); 113290001Sglebius 114290001Sglebius/** 115290001Sglebius * Create an array. 116290001Sglebius * @param p The pool to allocate the memory out of 117290001Sglebius * @param nelts the number of elements in the initial array 118290001Sglebius * @param elt_size The size of each element in the array. 119290001Sglebius * @return The new array 120290001Sglebius */ 121290001SglebiusAPR_DECLARE(apr_array_header_t *) apr_array_make(apr_pool_t *p, 122290001Sglebius int nelts, int elt_size); 123290001Sglebius 124290001Sglebius/** 125290001Sglebius * Add a new element to an array (as a first-in, last-out stack). 126290001Sglebius * @param arr The array to add an element to. 127290001Sglebius * @return Location for the new element in the array. 128290001Sglebius * @remark If there are no free spots in the array, then this function will 129290001Sglebius * allocate new space for the new element. 130290001Sglebius */ 131290001SglebiusAPR_DECLARE(void *) apr_array_push(apr_array_header_t *arr); 132290001Sglebius 133290001Sglebius/** A helper macro for accessing a member of an APR array. 134290001Sglebius * 135290001Sglebius * @param ary the array 136290001Sglebius * @param i the index into the array to return 137290001Sglebius * @param type the type of the objects stored in the array 138290001Sglebius * 139290001Sglebius * @return the item at index i 140290001Sglebius */ 141290001Sglebius#define APR_ARRAY_IDX(ary,i,type) (((type *)(ary)->elts)[i]) 142290001Sglebius 143290001Sglebius/** A helper macro for pushing elements into an APR array. 144290001Sglebius * 145290001Sglebius * @param ary the array 146290001Sglebius * @param type the type of the objects stored in the array 147290001Sglebius * 148290001Sglebius * @return the location where the new object should be placed 149290001Sglebius */ 150290001Sglebius#define APR_ARRAY_PUSH(ary,type) (*((type *)apr_array_push(ary))) 151290001Sglebius 152290001Sglebius/** 153290001Sglebius * Remove an element from an array (as a first-in, last-out stack). 154290001Sglebius * @param arr The array to remove an element from. 155290001Sglebius * @return Location of the element in the array. 156290001Sglebius * @remark If there are no elements in the array, NULL is returned. 157290001Sglebius */ 158290001SglebiusAPR_DECLARE(void *) apr_array_pop(apr_array_header_t *arr); 159290001Sglebius 160290001Sglebius/** 161290001Sglebius * Remove all elements from an array. 162290001Sglebius * @param arr The array to remove all elements from. 163290001Sglebius * @remark As the underlying storage is allocated from a pool, no 164290001Sglebius * memory is freed by this operation, but is available for reuse. 165290001Sglebius */ 166290001SglebiusAPR_DECLARE(void) apr_array_clear(apr_array_header_t *arr); 167290001Sglebius 168290001Sglebius/** 169290001Sglebius * Concatenate two arrays together. 170290001Sglebius * @param dst The destination array, and the one to go first in the combined 171290001Sglebius * array 172290001Sglebius * @param src The source array to add to the destination array 173290001Sglebius */ 174290001SglebiusAPR_DECLARE(void) apr_array_cat(apr_array_header_t *dst, 175290001Sglebius const apr_array_header_t *src); 176290001Sglebius 177290001Sglebius/** 178290001Sglebius * Copy the entire array. 179290001Sglebius * @param p The pool to allocate the copy of the array out of 180290001Sglebius * @param arr The array to copy 181290001Sglebius * @return An exact copy of the array passed in 182290001Sglebius * @remark The alternate apr_array_copy_hdr copies only the header, and arranges 183290001Sglebius * for the elements to be copied if (and only if) the code subsequently 184290001Sglebius * does a push or arraycat. 185290001Sglebius */ 186APR_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 */ 196APR_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*/ 206APR_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 */ 221APR_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 */ 232APR_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 */ 241APR_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 */ 252APR_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 */ 259APR_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 */ 268APR_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 */ 279APR_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 */ 291APR_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 */ 304APR_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 */ 312APR_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 */ 323APR_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 */ 335APR_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 */ 347APR_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 */ 360APR_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 */ 370APR_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 */ 384typedef 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 */ 406APR_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 */ 432APR_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 478APR_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 */ 491APR_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