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Editing: apr_tables.h
/* Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef APR_TABLES_H #define APR_TABLES_H /** * @file apr_tables.h * @brief APR Table library */ #include "apr.h" #include "apr_pools.h" #if APR_HAVE_STDARG_H #include <stdarg.h> /* for va_list */ #endif #ifdef __cplusplus extern "C" { #endif /* __cplusplus */ /** * @defgroup apr_tables Table and Array Functions * @ingroup APR * Arrays are used to store data which is referenced sequentially or * as a stack. Functions are provided to push and pop individual * elements as well as to operate on the entire array. * * Tables are used to store data which can be referenced by key. * Limited capabilities are provided for tables with multiple elements * which share a key; while key lookup will return only a single * element, iteration is available. Additionally, a table can be * compressed to resolve duplicates. * * Both arrays and tables may store string or binary data; some features, * such as concatenation or merging of elements, work only for string * data. * @{ */ /** the table abstract data type */ typedef struct apr_table_t apr_table_t; /** @see apr_array_header_t */ typedef struct apr_array_header_t apr_array_header_t; /** An opaque array type */ struct apr_array_header_t { /** The pool the array is allocated out of */ apr_pool_t *pool; /** The amount of memory allocated for each element of the array */ int elt_size; /** The number of active elements in the array */ int nelts; /** The number of elements allocated in the array */ int nalloc; /** The elements in the array */ char *elts; }; /** * The (opaque) structure for string-content tables. */ typedef struct apr_table_entry_t apr_table_entry_t; /** The type for each entry in a string-content table */ struct apr_table_entry_t { /** The key for the current table entry */ char *key; /* maybe NULL in future; * check when iterating thru table_elts */ /** The value for the current table entry */ char *val; /** A checksum for the key, for use by the apr_table internals */ apr_uint32_t key_checksum; }; /** * Get the elements from a table. * @param t The table * @return An array containing the contents of the table */ APR_DECLARE(const apr_array_header_t *) apr_table_elts(const apr_table_t *t); /** * Determine if the table is empty (either NULL or having no elements). * @param t The table to check * @return True if empty, False otherwise */ APR_DECLARE(int) apr_is_empty_table(const apr_table_t *t); /** * Determine if the array is empty (either NULL or having no elements). * @param a The array to check * @return True if empty, False otherwise */ APR_DECLARE(int) apr_is_empty_array(const apr_array_header_t *a); /** * Create an array. * @param p The pool to allocate the memory out of * @param nelts the number of elements in the initial array * @param elt_size The size of each element in the array. * @return The new array */ APR_DECLARE(apr_array_header_t *) apr_array_make(apr_pool_t *p, int nelts, int elt_size); /** * Add a new element to an array (as a first-in, last-out stack). * @param arr The array to add an element to. * @return Location for the new element in the array. * @remark If there are no free spots in the array, then this function will * allocate new space for the new element. */ APR_DECLARE(void *) apr_array_push(apr_array_header_t *arr); /** A helper macro for accessing a member of an APR array. * * @param ary the array * @param i the index into the array to return * @param type the type of the objects stored in the array * * @return the item at index i */ #define APR_ARRAY_IDX(ary,i,type) (((type *)(ary)->elts)[i]) /** A helper macro for pushing elements into an APR array. * * @param ary the array * @param type the type of the objects stored in the array * * @return the location where the new object should be placed */ #define APR_ARRAY_PUSH(ary,type) (*((type *)apr_array_push(ary))) /** * Remove an element from an array (as a first-in, last-out stack). * @param arr The array to remove an element from. * @return Location of the element in the array. * @remark If there are no elements in the array, NULL is returned. */ APR_DECLARE(void *) apr_array_pop(apr_array_header_t *arr); /** * Remove all elements from an array. * @param arr The array to remove all elements from. * @remark As the underlying storage is allocated from a pool, no * memory is freed by this operation, but is available for reuse. */ APR_DECLARE(void) apr_array_clear(apr_array_header_t *arr); /** * Concatenate two arrays together. * @param dst The destination array, and the one to go first in the combined * array * @param src The source array to add to the destination array */ APR_DECLARE(void) apr_array_cat(apr_array_header_t *dst, const apr_array_header_t *src); /** * Copy the entire array. * @param p The pool to allocate the copy of the array out of * @param arr The array to copy * @return An exact copy of the array passed in * @remark The alternate apr_array_copy_hdr() copies only the header, and arranges * for the elements to be copied if (and only if) the code subsequently * does a push or arraycat. */ APR_DECLARE(apr_array_header_t *) apr_array_copy(apr_pool_t *p, const apr_array_header_t *arr); /** * Copy the headers of the array, and arrange for the elements to be copied if * and only if the code subsequently does a push or arraycat. * @param p The pool to allocate the copy of the array out of * @param arr The array to copy * @return An exact copy of the array passed in * @remark The alternate apr_array_copy() copies the *entire* array. */ APR_DECLARE(apr_array_header_t *) apr_array_copy_hdr(apr_pool_t *p, const apr_array_header_t *arr); /** * Append one array to the end of another, creating a new array in the process. * @param p The pool to allocate the new array out of * @param first The array to put first in the new array. * @param second The array to put second in the new array. * @return A new array containing the data from the two arrays passed in. */ APR_DECLARE(apr_array_header_t *) apr_array_append(apr_pool_t *p, const apr_array_header_t *first, const apr_array_header_t *second); /** * Generate a new string from the apr_pool_t containing the concatenated * sequence of substrings referenced as elements within the array. The string * will be empty if all substrings are empty or null, or if there are no * elements in the array. If sep is non-NUL, it will be inserted between * elements as a separator. * @param p The pool to allocate the string out of * @param arr The array to generate the string from * @param sep The separator to use * @return A string containing all of the data in the array. */ APR_DECLARE(char *) apr_array_pstrcat(apr_pool_t *p, const apr_array_header_t *arr, const char sep); /** * Make a new table. * @param p The pool to allocate the pool out of * @param nelts The number of elements in the initial table. * @return The new table. * @warning This table can only store text data */ APR_DECLARE(apr_table_t *) apr_table_make(apr_pool_t *p, int nelts); /** * Create a new table and copy another table into it. * @param p The pool to allocate the new table out of * @param t The table to copy * @return A copy of the table passed in * @warning The table keys and respective values are not copied */ APR_DECLARE(apr_table_t *) apr_table_copy(apr_pool_t *p, const apr_table_t *t); /** * Create a new table whose contents are deep copied from the given * table. A deep copy operation copies all fields, and makes copies * of dynamically allocated memory pointed to by the fields. * @param p The pool to allocate the new table out of * @param t The table to clone * @return A deep copy of the table passed in */ APR_DECLARE(apr_table_t *) apr_table_clone(apr_pool_t *p, const apr_table_t *t); /** * Delete all of the elements from a table. * @param t The table to clear */ APR_DECLARE(void) apr_table_clear(apr_table_t *t); /** * Get the value associated with a given key from the table. After this call, * the data is still in the table. * @param t The table to search for the key * @param key The key to search for (case does not matter) * @return The value associated with the key, or NULL if the key does not exist. */ APR_DECLARE(const char *) apr_table_get(const apr_table_t *t, const char *key); /** * Get values associated with a given key from the table. If more than one * value exists, return a comma separated list of values. After this call, the * data is still in the table. * @param p The pool to allocate the combined value from, if necessary * @param t The table to search for the key * @param key The key to search for (case does not matter) * @return The value associated with the key, or NULL if the key does not exist. */ APR_DECLARE(const char *) apr_table_getm(apr_pool_t *p, const apr_table_t *t, const char *key); /** * Add a key/value pair to a table. If another element already exists with the * same key, this will overwrite the old data. * @param t The table to add the data to. * @param key The key to use (case does not matter) * @param val The value to add * @remark When adding data, this function makes a copy of both the key and the * value. */ APR_DECLARE(void) apr_table_set(apr_table_t *t, const char *key, const char *val); /** * Add a key/value pair to a table. If another element already exists with the * same key, this will overwrite the old data. * @param t The table to add the data to. * @param key The key to use (case does not matter) * @param val The value to add * @warning When adding data, this function does not make a copy of the key or * the value, so care should be taken to ensure that the values will * not change after they have been added.. */ APR_DECLARE(void) apr_table_setn(apr_table_t *t, const char *key, const char *val); /** * Remove data from the table. * @param t The table to remove data from * @param key The key of the data being removed (case does not matter) */ APR_DECLARE(void) apr_table_unset(apr_table_t *t, const char *key); /** * Add data to a table by merging the value with data that has already been * stored. The merging is done by concatenating the two values, separated * by the string ", ". * @param t The table to search for the data * @param key The key to merge data for (case does not matter) * @param val The data to add * @remark If the key is not found, then this function acts like apr_table_add() */ APR_DECLARE(void) apr_table_merge(apr_table_t *t, const char *key, const char *val); /** * Add data to a table by merging the value with data that has already been * stored. The merging is done by concatenating the two values, separated * by the string ", ". * @param t The table to search for the data * @param key The key to merge data for (case does not matter) * @param val The data to add * @remark If the key is not found, then this function acts like apr_table_addn() */ APR_DECLARE(void) apr_table_mergen(apr_table_t *t, const char *key, const char *val); /** * Add data to a table, regardless of whether there is another element with the * same key. * @param t The table to add to * @param key The key to use * @param val The value to add. * @remark When adding data, this function makes a copy of both the key and the * value. */ APR_DECLARE(void) apr_table_add(apr_table_t *t, const char *key, const char *val); /** * Add data to a table, regardless of whether there is another element with the * same key. * @param t The table to add to * @param key The key to use * @param val The value to add. * @remark When adding data, this function does not make a copy of the key or the * value, so care should be taken to ensure that the values will not * change after they have been added. */ APR_DECLARE(void) apr_table_addn(apr_table_t *t, const char *key, const char *val); /** * Merge two tables into one new table. * @param p The pool to use for the new table * @param overlay The first table to put in the new table * @param base The table to add at the end of the new table * @return A new table containing all of the data from the two passed in */ APR_DECLARE(apr_table_t *) apr_table_overlay(apr_pool_t *p, const apr_table_t *overlay, const apr_table_t *base); /** * Declaration prototype for the iterator callback function of apr_table_do() * and apr_table_vdo(). * @param rec The data passed as the first argument to apr_table_[v]do() * @param key The key from this iteration of the table * @param value The value from this iteration of the table * @remark Iteration continues while this callback function returns non-zero. * To export the callback function for apr_table_[v]do() it must be declared * in the _NONSTD convention. * @see apr_table_do @see apr_table_vdo */ typedef int (apr_table_do_callback_fn_t)(void *rec, const char *key, const char *value); /** * Iterate over a table running the provided function once for every * element in the table. The varargs array must be a list of zero or * more (char *) keys followed by a NULL pointer. If zero keys are * given, the @p comp function will be invoked for every element * in the table. Otherwise, the function is invoked only for those * elements matching the keys specified. * * If an invocation of the @p comp function returns zero, * iteration will continue using the next specified key, if any. * * @param comp The function to run * @param rec The data to pass as the first argument to the function * @param t The table to iterate over * @param ... A varargs array of zero or more (char *) keys followed by NULL * @return FALSE if one of the comp() iterations returned zero; TRUE if all * iterations returned non-zero * @see apr_table_do_callback_fn_t @see apr_table_vdo */ APR_DECLARE_NONSTD(int) apr_table_do(apr_table_do_callback_fn_t *comp, void *rec, const apr_table_t *t, ...) #if defined(__GNUC__) && __GNUC__ >= 4 __attribute__((sentinel)) #endif ; /** * Iterate over a table running the provided function once for every * element in the table. The @p vp varargs parameter must be a * list of zero or more (char *) keys followed by a NULL pointer. If * zero keys are given, the @p comp function will be invoked for * every element in the table. Otherwise, the function is invoked * only for those elements matching the keys specified. * * If an invocation of the @p comp function returns zero, * iteration will continue using the next specified key, if any. * * @param comp The function to run * @param rec The data to pass as the first argument to the function * @param t The table to iterate over * @param vp List of zero or more (char *) keys followed by NULL * @return FALSE if one of the comp() iterations returned zero; TRUE if all * iterations returned non-zero * @see apr_table_do_callback_fn_t @see apr_table_do */ APR_DECLARE(int) apr_table_vdo(apr_table_do_callback_fn_t *comp, void *rec, const apr_table_t *t, va_list vp); /** flag for overlap to use apr_table_setn */ #define APR_OVERLAP_TABLES_SET (0) /** flag for overlap to use apr_table_mergen */ #define APR_OVERLAP_TABLES_MERGE (1) /** flag for overlap to use apr_table_addn */ #define APR_OVERLAP_TABLES_ADD (2) /** * For each element in table b, either use setn or mergen to add the data * to table a. Which method is used is determined by the flags passed in. * @param a The table to add the data to. * @param b The table to iterate over, adding its data to table a * @param flags How to add the table to table a. One of: * APR_OVERLAP_TABLES_SET Use apr_table_setn * APR_OVERLAP_TABLES_MERGE Use apr_table_mergen * APR_OVERLAP_TABLES_ADD Use apr_table_addn * @remark When merging duplicates, the two values are concatenated, * separated by the string ", ". * @remark This function is highly optimized, and uses less memory and CPU cycles * than a function that just loops through table b calling other functions. */ /** * Conceptually, apr_table_overlap does this: * * <pre> * apr_array_header_t *barr = apr_table_elts(b); * apr_table_entry_t *belt = (apr_table_entry_t *)barr->elts; * int i; * * for (i = 0; i < barr->nelts; ++i) { * if (flags & APR_OVERLAP_TABLES_MERGE) { * apr_table_mergen(a, belt[i].key, belt[i].val); * } * else if (flags & APR_OVERLAP_TABLES_ADD) { * apr_table_addn(a, belt[i].key, belt[i].val); * } * else { * apr_table_setn(a, belt[i].key, belt[i].val); * } * } * </pre> * * Except that it is more efficient (less space and cpu-time) especially * when b has many elements. * * Notice the assumptions on the keys and values in b -- they must be * in an ancestor of a's pool. In practice b and a are usually from * the same pool. */ APR_DECLARE(void) apr_table_overlap(apr_table_t *a, const apr_table_t *b, unsigned flags); /** * Eliminate redundant entries in a table by either overwriting * or merging duplicates. * * @param t Table. * @param flags APR_OVERLAP_TABLES_MERGE to merge, or * APR_OVERLAP_TABLES_SET to overwrite, or * APR_OVERLAP_TABLES_ADD to add * @remark When merging duplicates, the two values are concatenated, * separated by the string ", ". */ APR_DECLARE(void) apr_table_compress(apr_table_t *t, unsigned flags); /** @} */ #ifdef __cplusplus } #endif #endif /* ! APR_TABLES_H */
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