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