/* ==================================================================== * The Apache Software License, Version 1.1 * * Copyright (c) 2000-2002 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, * if any, must include the following acknowledgment: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowledgment may appear in the software itself, * if and wherever such third-party acknowledgments normally appear. * * 4. The names "Apache" and "Apache Software Foundation" must * not be used to endorse or promote products derived from this * software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache", * nor may "Apache" appear in their name, without prior written * permission of the Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * . * * Portions of this software are based upon public domain software * originally written at the National Center for Supercomputing Applications, * University of Illinois, Urbana-Champaign. */ #ifndef CACHE_HASH_H #define CACHE_HASH_H #ifdef __cplusplus extern "C" { #endif #include "mod_cache.h" /** * @file cache_hash.h * @brief Cache Hash Tables */ /** * @defgroup Cache_Hash Hash Tables * @ingroup CACHE * @{ */ /** * When passing a key to cache_hash_set or cache_hash_get, this value can be * passed to indicate a string-valued key, and have cache_hash compute the * length automatically. * * @remark cache_hash will use strlen(key) for the length. The null-terminator * is not included in the hash value (why throw a constant in?). * Since the hash table merely references the provided key (rather * than copying it), cache_hash_this() will return the null-term'd key. */ #define CACHE_HASH_KEY_STRING (-1) /** * Abstract type for hash tables. */ typedef struct cache_hash_t cache_hash_t; /** * Abstract type for scanning hash tables. */ typedef struct cache_hash_index_t cache_hash_index_t; /** * Create a hash table. * @param size * @return The hash table just created */ CACHE_DECLARE(cache_hash_t *) cache_hash_make(apr_size_t size); /** * Create a hash table. * @param *ht Pointer to the hash table to be freed. * @return void * @remark The caller should ensure that all objects have been removed * from the cache prior to calling cache_hash_free(). Objects * not removed from the cache prior to calling cache_hash_free() * will be unaccessable. */ CACHE_DECLARE(void) cache_hash_free(cache_hash_t *ht); /** * Associate a value with a key in a hash table. * @param ht The hash table * @param key Pointer to the key * @param klen Length of the key. Can be CACHE_HASH_KEY_STRING to use the string length. * @param val Value to associate with the key * @remark If the value is NULL the hash entry is deleted. * @return The value of the deleted cache entry (so the caller can clean it up). */ CACHE_DECLARE(void *) cache_hash_set(cache_hash_t *ht, const void *key, apr_ssize_t klen, const void *val); /** * Look up the value associated with a key in a hash table. * @param ht The hash table * @param key Pointer to the key * @param klen Length of the key. Can be CACHE_HASH_KEY_STRING to use the string length. * @return Returns NULL if the key is not present. */ CACHE_DECLARE(void *) cache_hash_get(cache_hash_t *ht, const void *key, apr_ssize_t klen); /** * Start iterating over the entries in a hash table. * @param ht The hash table * @example */ /** * 
 * 
 *     int sum_values(cache_hash_t *ht)
 *     {
 *         cache_hash_index_t *hi;
 * 	   void *val;
 * 	   int sum = 0;
 * 	   for (hi = cache_hash_first(ht); hi; hi = cache_hash_next(hi)) {
 * 	       cache_hash_this(hi, NULL, NULL, &val);
 * 	       sum += *(int *)val;
 * 	   }
 * 	   return sum;
 *     }
 * 
 * There is no restriction on adding or deleting hash entries during an
 * iteration (although the results may be unpredictable unless all you do
 * is delete the current entry) and multiple iterations can be in
 * progress at the same time.
 *
*/ CACHE_DECLARE(cache_hash_index_t *) cache_hash_first(cache_hash_t *ht); /** * Continue iterating over the entries in a hash table. * @param hi The iteration state * @return a pointer to the updated iteration state. NULL if there are no more * entries. */ CACHE_DECLARE(cache_hash_index_t *) cache_hash_next(cache_hash_index_t *hi); /** * Get the current entry's details from the iteration state. * @param hi The iteration state * @param key Return pointer for the pointer to the key. * @param klen Return pointer for the key length. * @param val Return pointer for the associated value. * @remark The return pointers should point to a variable that will be set to the * corresponding data, or they may be NULL if the data isn't interesting. */ CACHE_DECLARE(void) cache_hash_this(cache_hash_index_t *hi, const void **key, apr_ssize_t *klen, void **val); /** * Get the number of key/value pairs in the hash table. * @param ht The hash table * @return The number of key/value pairs in the hash table. */ CACHE_DECLARE(int) cache_hash_count(cache_hash_t *ht); /** @} */ #ifdef __cplusplus } #endif #endif /* !CACHE_HASH_H */