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diff --git a/include/apr_tables.h b/include/apr_tables.h new file mode 100644 index 0000000..7ce2ada --- /dev/null +++ b/include/apr_tables.h @@ -0,0 +1,507 @@ +/* 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 */ |